Note: Descriptions are shown in the official language in which they were submitted.
HEAVY OIL UPGRADE PROCESS
INCLUDING RECOVERY OF SPENT CATALYST
RELATED APPLICATIONS
This application claims priority to US Patent Application Serial No.
12/004,014 filed December 20, 2007; and US Patent Application Serial No.
12/004,015 also filed December 20, 2007. This application claims priority to
and
benefits from the foregoing.
BACKGROUND
[001] As light oil reserves are gradually being depleted and the costs of
development (e.g., lifting, mining, and extraction) of heavy oil resources
have
decreased, a need has arisen to develop novel upgrading technologies to
convert
heavy oils and bitumens into lighter products. With the advent of heavier
crude
feedstock, refiners are forced to use more catalysts than before to upgrade
the heavy
oil and remove contaminants / sulfur from these feedstocks. These catalytic
processes
generate huge quantities of spent catalyst. With the increasing demand and
market
price for metal values and environmental awareness thereof, catalysts can
serve as a
secondary source for metal recovery.
[002] In order to recycle / recover catalytic metals and provide a renewable
source for the metals, efforts have been made to extract metals from spent
catalysts
generated from heavy oil upgrade processes, whether in supported or bulk
catalyst
form. Before catalytic metals can be extracted / recovered from spent
catalysts,
residual heavy oil from hydroprocessing operations has first to be separated
from the
spent catalysts. Effluent streams from heavy oil upgrade system typically
contain
unconverted heavy oil materials, heavier hydrocracked liquid products, slurry
catalyst
ranging from 3 to 50 wt. %, small amounts of coke, asphaltenes, etc.
Conventional
filtration processes may not be suitable to separate / recover slurry catalyst
from high
molecular weight hydrocarbon materials in the effluent streams as the
unsupported
fine catalyst may cause plugging or fouling of filters.
[003] Membrane technology has long been used in removal of contaminants
in environmental clean-up, wastewater treatment and water purification,
particularly
with the use of microfiltration, ultrafiltration, nanofiltration and reverse
osmosis.
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vanadium (in ppm amounts) from low boiling hydrocarbon mixtures boiling such
as
kerosene.
[004] Heavy oil exposed to hydrocracking conditions is particularly difficult
to extract / remove / separate from slurry catalyst. Conventional solvent
extraction
and roasting methods in the prior art do not work particularly well with
slurry
catalyst, leaving heavy oil behind with the catalyst particle, thus creating
problems in
the downstream metal recovery process (recovering valuable metals from spent
catalyst). Some chemicals in the residual entrained oil in catalyst particles
cause
foaming issues during the metals recovery process and negatively impact any
attempts
at metals recovery using chemical extraction, pressure leaching, metal
digestion /
solubilization, crystallization, and or precipitation methodologies.
[005] The present invention relates to novel applications of membrane
technology in separating and / or extracting residual heavy oil from spent
catalyst
particles generated from heavy oil upgrade operations.
SUMMARY
[006] In one aspect, an integrated system for heavy oil upgrade is provided,
the system comprises a heavy oil upgrade unit, a catalyst deoiling unit for
separating
spent slurry catalyst for unconverted heavy oil, a metal recovery unit for
recovering
valuable metals from the deoiled spent slurry catalyst, and a catalyst
synthesis unit for
forming slurry catalyst from recovered metals.
[007] In another aspect, a system for separating heavy oil from catalyst
particles is provided. The system utilizes a filtration assembly having at
least a
membrane with a sufficient pore size for removing at least 90% of the heavy
oil from
the catalyst particles. In one embodiment, the filtration assembly comprises a
plurality of filtration units, selected from cross-flow filtration,
dialfiltration, dynamic
filtration, cross-flow sedimentation, co-current sedimentation separation,
countercurrent sedimentation separation, and settling tanks.
[008] In yet a third aspect, a method for separating fine catalyst from heavy
oil using dynamic filtration provided. The method comprises subjecting a
mixture of
fine catalyst in heavy oil to vibratory dynamic filtration with a shear force
of at least
about 20,000 sec-I.
[009] In a fourth aspect, a method for separating fine catalyst from heavy oil
using filtration sedimentation provided. The method employs a sedimentation
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separator having a module with a plurality of membranes in the form of
channels and
wherein the channels are inclined downward to facilitate the separation of the
heavy
oil from the catalyst.
[010] In fifth aspect, a system for separating heavy oil from catalyst
particles is provided with a drying zone comprising at least two drying
stages, with
the 2nd drying stage for the volatilization of the organic matters, e.g.,
solvent and
heavy oil, from the catalyst particles. In one embodiment, the first drying
zone is a
combined horizontal and vertical wiped-film dryer / evaporator (or combined
horizontal and vertical thin-film dryer / evaporator) and the second zone is a
rotary
kiln dryer.
[010a] In another aspect, a system for separating hydrocarbons including
solvents and heavy oil from catalyst particles, the system comprising:
a vessel for containing a stream comprising a mixture of catalyst particles
and
50 to 90 wt. % hydrocarbons;
a plasma system for heating the mixture of catalyst particles and hydrocarbons
to a sufficient temperature to volatilize and remove at least 90% of the
hydrocarbons
from the catalyst particles; and
means for collecting the volatized hydrocarbons.
[010b] In another aspect a process for separating hydrocarbons including
solvents and heavy oil from catalyst particulates, the process comprising:
providing a stream comprising a mixture of catalyst particulates and 50 to 90
wt. % hydrocarbons;
subjecting the mixture of catalyst particulates and hydrocarbons to a plasma
source, wherein the mixture of catalyst particulates and hydrocarbons is
heated to a
temperature between 400 to 900 C for a sufficient amount of time to volatize
the
hydrocarbons and produce effluent gases; and
removing the effluent gases containing hydrocarbons; and
collecting the catalyst particulates as a dry powder having less than 0.5 wt.
%
hydrocarbons.
[010c] In another aspect, a process for separating heavy oil from catalyst
particles, the process comprising:
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a) providing a feed stream comprising a mixture of 5 -40 wt. % catalyst
particles in heavy oil;
b) adding a sufficient amount of non-aqueous solvent to the mixture of
catalyst particles in heavy oil to reduce the heavy oil concentration at least
40%,
thereby causing the mixture to separate into two phases: a) a top phase
comprising a
portion of the heavy oil and non-aqueous solvent; and b) a bottom phase
comprising
the catalyst particles, a portion of the non-aqueous solvent, a heavy oil
concentration
less than an initial heavy oil concentration in the feed stream; and
c) recovering the bottom phase comprising catalyst particles in solvent and
with a reduced heavy oil concentration.
[010d] In another aspect, a process for removing hydrocarbons including
solvents and heavy oil from catalyst particles, the process comprising:
providing a stream comprising catalyst particles and 50 to 90 wt. %
hydrocarbons;
passing the stream comprising catalyst particles and hydrocarbons through a
drying zone comprising at least two drying apparatuses, a first drying
apparatus and a
second drying apparatus, wherein the second drying apparatus is operated at a
sufficiently high temperature for removing at least 90% of hydrocarbons from
the
catalyst particles; and
removing the catalyst particles from the drying zone as a dry powder.
[010e] In another aspect, a process for removing hydrocarbons including
solvents and heavy oil from catalyst particles, the process comprising:
providing a stream comprising catalyst particles and 50 to 90 wt. %
hydrocarbons;
passing the stream comprising catalyst particles and hydrocarbons through a
drying zone comprising at least two drying apparatuses, a first drying
apparatus and a
second drying apparatus, wherein the second drying apparatus is operated at a
sufficiently high temperature for removing at least 90% of hydrocarbons from
the
catalyst particles; and
removing the catalyst particles from the drying zone as a dry powder.
[011] In yet another aspect, a system for separating hydrocarbons from
catalyst particles is provided with the use of at least a surfactant to remove
/ cleanse
organic matters including solvent and heavy oil from the catalyst particles.
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BRIEF DESCRIPTION OF THE DRAWING FIGURES
[012] Figure 1 A is a cross-sectional view of a plate and frame filtration
unit.
[013] Figure IB is a partially developed view showing an embodiment of a
membrane filtration system with a pleated membrane structure.
[014] Figure IC is a schematic diagram of a membrane filtration system
with a tubular membrane filter.
[015] Figure 1 D is a perspective view of a membrane system having a
plurality of tubular / hollow membrane filters.
[016] Figure IE is a perspective view of a membrane system in a spiral
wound form.
[017] Figure 2 is a schematic diagram of a countercurrent sedimentation
separator with membrane channels arranged in parallel and two opposite
(countercurrent) inflow streams into a receiving chamber.
[018] Figure 3 is a schematic diagram of a cross-flow sedimentation
separator with membrane channels arranged in parallel, with an inflow stream
on one
side of the channels and an outlet (filtrate) stream at the opposite side of
the channels.
[019] Figure 4 is a block diagram of an embodiment of a deoiling operation.
[020] Figure 5 is a block diagram of another embodiment of a deoiling unit,
with a concentration zone.
[021] Figure 6 is a block diagram showing a third embodiment of a deoiling
unit, with a slurry concentration zone.
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[022] Figure 7 is a block diagram showing another embodiment of a deoiling
unit, employing a concentration zone as well as a slurry concentration zone.
[023] Figure 8 is a block diagram illustrating an embodiment of a membrane
filtration system with multiple cross-flow filtration units,
[024] Figure 9 is a block diagram illustrating an embodiment of a membrane
filtration system with a settling tank for solvent washing.
[025] Figure 10 is a block diagram illustrating an embodiment of a deoiling
system with a membrane filtration zone and a two-staged drying zone, including
a
Combi dryer and a rotary kiln dryer.
[026] Figure 11 is a block diagram showing a recirculation operation in an
embodiment employing dynamic filtration, e.g., a Vibratory Shear Enhanced
Processing (V*SEP) unit.
[027] Figure 12 is a graph of a membrane study in an embodiment
employing dynamic filtration, e.g., a V*SEP unit.
[028] Figure 13 is a graph of a pressure study in an embodiment employing
dynamic filtration, e.g,, a V*SEP unit.
[029] Figure 14 is a block diagram showing a batch operation employing
dynamic filtration, e.g., a V*SEP unit.
[030] Figure 15 is a graph of a diafiltration study in an embodiment
employing dynamic filtration, e.g., a V*SEP unit.
[031] Figure 16 is a graph of particle size distribution in an embodiment
employing dynamic filtration, e.g., a V*SEP unit.
DETAILED DESCRIPTION
[032] The following terms will be used throughout the specification and will
have the following meanings unless otherwise indicated.
[033] "Average flux" refers to a time weighted average flux measured over a
particular concentration range.
[034] "Batch concentration" refers to a dynamic filtration system, e.g., a
Vibratory Shear Enhanced Processing (V*SEP) machine configuration, where a
fixed
amount of feed slurry is progressively concentrated by removal of permeate
from the
system. The concentrate from the system is returned to a feed tank.
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[035] "Concentrate," also known as "retentate," refers to the portion of
slurry
that does not permeate through a filter medium, e.g., a membrane. Stated
otherwise, it
is the portion of slurry which does not filter through the membrane.
[036] "Concentration factor" refers to a ratio of feed flow rate to
concentrate
flow rate.
[037] "Cross-flow" filtration (or crossflow filtration or tangential flow
filtration (TFF)) refers to a filtration technique in which the feed stream
flows
(parallel or tangentially) along the surface of the membrane and the filtrate
flows
across the membrane. In cross-flow filtration, typically only the material
which is
smaller than the membrane pore size passes through (across) the membrane as
permeate or filtrate, and everything else is retained on the feed side of the
membrane
as retentate or concentrate. In one embodiment of cross-flow filtration, only
a
portion of the liquid in the solids-containing stream passing through the
filter
medium, i.e., the membrane. In contrast, in conventional filtration (dead-end
filtration or normal filtration), the entire liquid portion of the slurry,
rather than just a
fraction of the liquid, is forced through the membrane, with most or all of
the solids
retained by the membrane.
[038] "Diafiltration" (DF) refers to a cross-flow filtration process wherein a
buffer material, e.g., a solvent, is added into the feed stream and / or the
filtering
process while filtrate is removed continuously from the process. In one
embodiment
of diafiltration, the process is used for purifying retained large molecular
weight
species, increasing the recovery of low molecular weight species, buffer
exchange and
simply changing the properties of a given solution. Diafiltration can be in
the form
of batch diafiltration or continuous diafiltration. In batch DF, the retentate
is
concentrated to the original volume or up to a certain concentration of the
slurry
catalyst in the retentate. Once this concentration is reached, another volume
of feed
stream is added. In continuous DF, the volume of feed stream (solvent and
catalyst
slurry in heavy oil) is added to the filtration process at the same flow rate
at which the
filtrate and the concentrate are being removed. By this method, the volume of
the
fluid in the process can be kept constant while the smaller molecules, e.g.,
heavy oil
in solvent, which can permeate through the filter are washed away in the
filtrate.
[039] "Dynamic filtration" is an extension of cross-flow filtration, wherein
the filter medium is kept essentially free from plugging or fouling by
repelling
particulate matter from the filter element and by disrupting the formation of
cake
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layers adjacent to the filter medium. These results are accomplished by moving
the
material being filtered fast enough relative to the filtration medium to
produce high
shear rates as well as high lift forces on the particles, such as by use of
rotary,
oscillating, reciprocating, or vibratory means. The shear at the fluid-filter
medium
interface is nearly independent of any crossflow fluid velocity, unlike
tangential or
crossflow filtration techniques (which suffer from other problems such as
premature
filter plugging due to compound adsorption and large and nonuniform pressure
drops
associated with high tangential velocities along the filter length,
potentially causing
backflow through the filtration medium and reducing filtration).
[040] "Microfiltration" refers to a membrane filtration process in which
hydrostatic pressure forces a liquid against a membrane, employing microporous
membranes, i.e., membranes with pore size in the micron ranges.
Microfiltration can
be in the form of cross-flow filtration, diafiltration, or dynamic filtration.
In one
embodiment, the membrane size is less than 100 nm. In another embodiment, the
membrane size ranges from 0.01 to 10 microns (10 to 10,000 nanometers). In one
embodiment, membranes of sufficient sizes are used for particles greater than
or equal
to 0.1 vm or 500,000 daltons in size or weight, are retained.
[041] "Nanofiltration" refers to a membrane filtration process operates at a
low to moderately high pressure (typically > 4 bar, or in the range of 50 -
450 psig),
employing filters with very small pore sizes, i.e., nanofilters with membranes
having a
pore size in the order of nanometers (1 nanometer 10 angstroms or 0.001
microns).
[042] "Feed" may be used interchangeably with "feed slurry," refers to a
mixture comprising heavy oil and spent slurry catalyst, offered for
filtration. The feed
typically has suspended solids or molecules, which are to be segregated from a
clear
filtrate and reduced in size, making a concentrated solution of feed slurry.
[043] "Fouling" refers to accumulation of materials on a membrane surface
or structure, which results in a decrease in flux.
[044] "Flux" refers to a measurement of the volume of fluid that passes
through a membrane during a certain time interval for a set area of membrane
(i.e.,
gallons of permeate produced per ft2 of membrane per day (gfd) or liters per
m2 per
hour).
[045] "Instantaneous flux" refers to flux measured at a given moment in
time.
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[046] "Line-Out Study" refers to a procedure of measuring membrane flux
over time in order to determine eventual stability.
[047] "Optimum differential pressure" refers to a differential pressure value
above which the rate of change of flux with time, or the productivity of the
filtration
system, decreases.
[048] "Percent recovery" refers to a ratio of permeate flow rate to feed flow
rate.
[049] "Permeate," also known as "filtrate," refers to the portion of slurry
that
percolates through a membrane. The amount of solids and the particle size of
solids
contained in the filtrate are determined by the pore size of the
discriminating
membrane, among other factors.
[050] "Surfactant" or "surface acting agent" refers to any compound that
reduces surface tension when dissolved or suspended in water or water
solutions, or
which reduces interfacial tension between two liquids, or between a liquid and
a solid.
In a related aspect, there are at least three categories of surface active
agents:
detergents, wetting agents, and emulsifiers; all use the same basic chemical
mechanism and differ, for example, in the nature of the surfaces involved.
[051] "Detergent" refers to an emulsifying agent or surface active agent
made usually by action of alkali on fat or fatty acids, such as, but not
limited to, the
sodium or potassium salts of such acids, or sulfonates which are formed when
sulfonic acid is reacted with alkanes. In one embodiment, detergent may
include any
of numerous synthetic water-soluble or liquid organic preparations that are
chemically
different from soaps but are able to emulsify oils, hold dirt in suspension,
and act as
wetting agents,
[052] "Heavy oil" refers to heavy and ultra-heavy crudes, including but not
limited to resids, coals, bitumen, tar sands, etc. Heavy oil feedstock may be
liquid,
semi-solid, and for solid. Examples of heavy oil feedstock that might be
upgraded as
described herein include but are not limited to Canada Tar sands, vacuum resid
from
Brazilian Santos and Campos basins, Egyptian Gulf of Suez, Chad, Venezuelan
Zulia,
Malaysia, and Indonesia Sumatra. Other examples of heavy oil feedstock include
bottom of the barrel and residuum left over from refinery processes, including
"bottom of the barrel" and "residuum" (or "resid") -- atmospheric tower
bottoms,
which have a boiling point of at least 343 C. (650 F.), or vacuum tower
bottoms,
which have a boiling point of at least 524 C, (975 F.), or "resid pitch" and
"vacuum
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residue" ¨ which have a boiling point of 524 C, (975 F.) or greater.
Properties of
heavy oil feedstock may include, but are not limited to: TAN of at least 0:1,
at least
0.3, or at least 1; viscosity of at least 10 cSt; API gravity at most 20 in
one
embodiment, and at most 10 in another embodiment, and less than 5 in another
embodiment. A gram of heavy oil feedstock typically contains at least 0.0001
grams
of NiN/Fe; at least 0.005 grams of heteroatoms; at least 0.01 grams of
residue; at
least 0.04 grams C5 asphaltenes; at least 0.002 grams of MCR; per gram of
crude; at
least 0,00001 grams of alkali metal salts of one or more organic acids; and at
least
0.005 grams of sulfur. In one embodiment, the heavy oil feedstock has a sulfur
content of at least 5 wt. % and an API gravity of from -5 to +5. A heavy oil
feed
comprises Athabasca bitumen (Canada) typically has at least 50% by volume
vacuum
reside, A Boscan (Venezuela) heavy oil feed may contain at least 64 % by
volume
vacuum residue.
[053] As used herein, the term "spent catalyst" or "used catalyst" refers to a
catalyst that has been used in a hydroprocessing operation and whose activity
has
thereby been diminished, remain unchanged or has been enhanced. For example,
if a
reaction rate constant of a fresh catalyst at a specific temperature is
assumed to be
100%, the reaction rate constant for a spent catalyst temperature is 80% or
less in one
embodiment, and 50% or less in another embodiment. In one embodiment, the
metal
components of the spent catalyst comprise at least one of Group VB, VIB, and
VIII
metals, e.g., vanadium, molybdenum, tungsten, nickel, and cobalt. The most
commonly encountered metal is molybdenum. In one embodiment, the metals in a
spent catalyst are sulfides of Mo, Ni, and V.
[054] The terms "treatment," "treated," "upgrade, "upgrading" and
"upgraded", when used in conjunction with a heavy oil feedstock, describes a
heavy
oil feedstock that is or has been subjected to hydroprocessing, or a resulting
material
or crude product, having a reduction in the molecular weight of the heavy oil
feedstock, a reduction in the boiling point range of the feedstock, a
reduction in the
concentration of asphaltenes, a reduction in the concentration of hydrocarbon
free
radicals, and/or a reduction in the quantity of impurities, such as sulfur,
nitrogen,
oxygen, halides, and metals.
[055] In one embodiment, the invention relates to an integrated facility (or
system) comprising: 1) a heavy oil upgrade process (or zone), wherein a heavy
oil
feed is converted to lighter products; 2) a deoiling process or zone, wherein
residual
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heavy oil and heavier product oils are separated from the spent slurry
catalyst for
subsequent recovery; 3) a metal recovery zone, wherein metals are recovered
from the
spent catalyst; and 4) a catalyst synthesis zone, wherein catalysts are
synthesized from
metals from sources including metals recovered from the spent catalyst. Any of
the
zone can be operated in either batch mode, continuous mode, or combinations
thereof,
[056] In one embodiment of the invention with the recovery / separation of
spent catalyst from heavy oil, the heavy oil conversion rate can be up to
100%, In
one embodiment, an integrated system with a deoiling zone for recovery /
separation
of spent catalyst allows for up to 99.5% heavy oil conversion rate. In another
embodiment, the overall heavy oil conversion rate is up to 99%. As used
herein,
conversion rate refers to the conversion of heavy oil feedstock to less than
1000 F
(538 C) boiling point materials.
[057] Heavy Oil Upgrading. The upgrade or treatment of heavy oil feeds is
generally referred herein as "hydroprocessing." Hydroprocessing is meant any
process that is carried out in the presence of hydrogen, including, but not
limited to,
hydroconversion, hydrocracking, hydrogenation, hydrotreating,
hydrodesulfurization,
hydrodenitrogenation, hydrodemetallation, hydrodearomatization,
hydroisornerization, hydrodewaxing and hydrocracking including selective
hydrocracking. The products of hydroprocessing may show improved viscosities,
viscosity indices, saturates content, low temperature properties, volatilities
and
depolarization, etc.
[058] Heavy oil upgrade is utilized to convert heavy oils or bitumens into
commercially valuable lighter products, e.g., lower boiling hydrocarbons, in
one
embodiment include liquefied petroleum gas (LPG), gasoline, jet, diesel,
vacuum gas
oil (VGO), and fuel oils.
[059] In the heavy oil upgrade process, a heavy oil feed is treated or
upgraded by contact with a slurry catalyst feed in the presence of hydrogen
and
converted to lighter products, generating: a) an effluent stream containing a
mixture
of the upgraded products, the slurry catalyst, the hydrogen containing gas,
and
unconverted heavy oil feedstock, which effluent stream is subsequently passed
on to a
separation zone; and b) a stream defined herein as unconverted slurry bleed
oil stream
("USBO"), comprising spent finely divided unsupported catalyst, carbon fines,
and
metal fines in unconverted resid hydrocarbon oil and heavier hydrocracked
liquid
products (collectively, "heavy oil") as slurry catalyst. The solids content in
the
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USBO stream can be in the range of about 5-40 weight % in one embodiment. In a
second embodiment, 10-30 weight %, and in a third embodiment, about 15-25
weight
%. In one embodiment, the upgrade process comprises a plurality of
reactors or
contacting zones, with the reactors being the same or different in
configurations,
Examples of reactors that can be used herein include stacked bed reactors,
fixed bed
reactors, ebullating bed reactors, continuous stirred tank reactors, fluidized
bed
reactors, spray reactors, liquid / liquid contactors, slurry reactors, slurry
bubble
column reactors, liquid recirculation reactors, and combinations thereof.
[060] In one embodiment, at least one of the contacting zones further
comprises an in-line hydrotreater, capable of removing over 70% of the sulfur,
over
90% of nitrogen, and over 90% of the heteroatoms in the crude product being
processed. In one embodiment, the upgraded heavy oil feed from the contacting
zone is either fed directly into, or subjected to one or more intermediate
processes and
then fed directly into the separation zone, e.g., a flash drum or a high
pressure
separator, wherein gases and volatile liquids are separated from the non-
volatile
fraction, e.g., the unconverted slurry bleed oil stream ("USBO").
[061] In one embodiment, at least 90 wt % of heavy oil feed is converted to
lighter products in the upgrade system. In a second embodiment, at least 95%
of
heavy oil feed is converted to lighter products. In a third embodiment, the
conversion
rate is at least 98%. In a fourth embodiment, the conversion rate is at least
99.5%.
In a fifth embodiment, the conversion rate is at least 80%,
[062] In one embodiment, the heavy oil upgrade process employs a slurry
catalyst. The catalyst slurry can be concentrated prior to heavy oil
upgrading, for
example, to aid in the transport of catalyst (slurry) to the heavy oil
upgrading location.
Effluent streams from the reactor, perhaps following downstream processing,
such as,
for example, separation(s), can include one or more valuable light products as
well as
a stream containing spent slurry / unsupported catalyst in heavy oil
comprising
unconverted feed.
[063] Catalyst Synthesis: In one embodiment, the spent slurry catalyst to be
separated from heavy oil originates from a dispersed (bulk or unsupported)
Group
VIB metal sulfide catalyst promoted with at least one of: a Group VB metal
such as
V, Nb; a Group VIII metal such as Ni, Co; a Group VIIIB metal such as Fe; a
Group
IVI3 metal such as Ti; a Group IIB metal such as Zn, and combinations thereof.
Promoters are typically added to a catalyst formulation to improve selected
properties
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of the catalyst or to modify the catalyst activity and/or selectivity. In
another
embodiment, the slurry catalyst originates from a dispersed (bulk or
unsupported)
Group VIB metal sulfide catalyst promoted with a Group VIII metal for
hydrocarbon
oil hydroprocessing.
[064] In one embodiment, the slurry catalyst originates from a multi-metallic
catalyst comprising at least a Group VIB metal and optionally, at least a
Group VIII
metal (as a promoter), wherein the metals may be in elemental form or in the
form of
a compound of the metal. The metals for use in making the catalyst can be
metals
recovered from a downstream metal recovery unit, wherein metals such as
molybdenum, nickel, etc., are recovered from the deoiled spent slurry catalyst
for use
in the synthesis of fresh / new slurry catalyst.
[065] In one embodiment, the slurry catalyst originates from a catalyst
prepared from a mono-, di, or polynuclear molybdenum oxysulfide
dithiocarbamate
complex. In a second embodiment, the catalyst is prepared from a molybdenum
oxysulfide dithiocarbamate complex. In one embodiment, the slurry catalyst
originates from a catalyst prepared from catalyst precursor compositions
including
organometallic complexes or compounds, e.g,, oil soluble compounds or
complexes
of transition metals and organic acids. Examples of such compounds include
naphthenates, pentanedionates, octoates, and acetates of Group VIB and Group
VII
metals such as Mo, Co, W, etc, such as molybdenum naphthanate, vanadium
naphthanate, vanadium octoate, molybdenum hexacarbonyl, and vanadium
hexacarbonyl,
[066] In one embodiment, the catalyst slurry comprising catalyst particles (or
particles) having an average particle size of at least 1 micron in a
hydrocarbon oil
diluent. In another embodiment, the catalyst slurry comprises catalyst
particles
having an average particle size in the range of 1 ¨ 20 microns. In a third
embodiment, the catalyst particles have an average particle size in the range
of 2¨ 10
microns. In one embodiment, the slurry catalyst comprises a catalyst having an
average particle size ranging from colloidal (nanometer size) to about 1-2
microns.
In another embodiment, the slurry catalyst comprises a catalyst having
molecules
and/or extremely small particles that are colloidal in size (i.e., less than
100 run, less
than about 10 nm, less than about 5 nm, and less than about 1 run), forming
aggregates having an average size ranging from 1 to 10 microns in one
embodiment, 1
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to 20 microns in another embodiment, and less than 10 microns in yet a third
embodiment.
[067] Deoiling Zone. The system to extract / recover / separate heavy oil
from the slurry catalyst and / or concentrate a catalyst slurry is called a
deoiling zone
(or unit), In one embodiment of a deoiling zone, heavy oil is extracted or
separated
from catalyst particles, forming clean, dried solids, for subsequent recovery
in the
metal recovery zone. In one embodiment, the dcoiling zone comprises a number
of
separate sub-units including solvent wash (solvent extraction), filtration,
drying, and
solvent recovery sub-units.
[068] In one embodiment, the deoiling zone is used to concentrate a catalyst
slurry to a solids contents of, for example, about 60-70 weight %. Due, in
part, to the
concentrated catalyst slurry having a reduced volume as compared to the volume
of
the catalyst slurry prior to concentration, the concentrated catalyst slurry
can then be
more easily transported to a heavy oil upgrading site or reactor, where it can
be
reconstituted to a solids contents of, for example, about 5 weight %, prior to
heavy oil
upgrading.
[069] The term "spent catalyst slurry" refers to a catalyst slurry, whether a
spent catalyst slurry to be separated from heavy oil, or a fresh catalyst
slurry that
needs to be concentrated.
[070] The term "extract" may be used interchangeably with "separate" or
"recover" (or grammatical variations thereof), denoting the separation of
heavy oil
from catalyst particles (or particles).
[071] In one embodiment, the feed stream to the deoiling zone is a catalyst
bleed stream from a heavy oil upgrade or vacuum resid unit, e.g., unconverted
slurry
bleed oil ("USBO") stream, comprising spent finely divided unsupported
catalyst,
carbon fines, and metal fines in unconverted resid hydrocarbon oil and heavier
hydrocracked liquid products (collectively, "heavy oil"). In one embodiment,
the
USBO feed stream to the deoiling process has a spent catalyst concentration
(as
solids) ranging from 5-40 weight %. In another embodiment, the spent catalyst
solid
ranges from 10 to 20 wt. % of the total USBO feed stream. The clean dried
solids
leaving the deoiling process consists essentially of spent catalyst solids, in
one
embodiment having less than 1 wt. % oil, on a solvent free basis, with less
than 500
ppm of solvent.
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Date Recue/Date Received 2020-08-06
[072] In one embodiment, the feedstock stream is first combined with
solvent to form a combined slurry-solvent stream prior to being filtered via
membrane
filtration, In another embodiment, the feedstock stream and the solvent are
fed to the
filter as separate feed streams wherein they are combined in the filtration
process. In
one embodiment, fresh solvent is used for the solvent wash. In another
embodiment,
recycled solvent from another part of the process is used. In yet a third
embodiment,
a mixture of fresh solvent and recycled solvent is employed. In a fourth
embodiment,
fresh solvent and recycled solvent are employed as separate streams. The
feedstock
and solvent streams can be combined prior to the deoiling zone or in the
deoiling
zone.
[073] Via membrane filtration, spent catalyst is separated from the heavy oil,
i.e., "deoiled," in solvent as a separate stream. A second stream is produced
comprising the heavy oil and solvent. Solvent can be subsequently separated
from
the catalyst using processes including evaporation to dryness. Solvent can
also be
recovered from the stream comprising the heavy oil and solvent for subsequent
reuse,
with the recovered heavy oil being a product.
[074] In one embodiment, in addition to or in place of membrane filtration,
other separation techniques can be employed including inclined plate settlers,
conventional settling tanks, inclined settlers with vibratory separation
device, as long
as the vibration is not transmitted to the settler / sedimentation unit.
[075] Membrane Filtration: In one embodiment, a membrane filtration
assembly, e.g., microfiltration, is employed in the deoiling zone to separate
the heavy
oil from the catalyst. In the filtration assembly, a feed stream comprising
slurry
catalyst in heavy oil is transformed into two streams, a first stream
containing
primarily hydrocarbons, e.g., a mixture of heavy oil and solvent, and a second
stream
containing catalyst solids with reduced heavy oil concentration in solvent. As
used in
the context of the deoiling zone! membrane filtration, "heavy oil" will refer
to
unconverted resid hydrocarbon oil, heavier hydrocracked liquid products, and
mixtures thereof.
[076] The membranes employed can be of the "tortuous-pore" or "capillary-
pore" type, or a combination of multiple membrane layers, some tortuous-pore
membranes some capillary-pore membranes. As used herein, tortuous-pore refers
to
membranes having a structure resembles a sponge with a network of
interconnecting
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Date Recue/Date Received 2020-08-06
tortuous pores. Capillary-pore refers to membranes having approximately
straight-
through cylindrical capillaries.
[077] Any suitable filtration medium (membrane) can be utilized in the
filtration assembly. In one embodiment, the filtration medium is a porous
material
which permits heavy oil below a certain size to flow through as the filtrate
(or
permeate) while retaining the spent catalyst particles in the retentate. In
one
embodiment, the filter medium is of sufficient pore size for removing at least
50% of
the heavy oil from the spent catalyst, i.e., for at least 50% of the heavy oil
to pass
through the filter membrane. In another embodiment, the filter membrane is of
sufficient pore size for at least 60% of the heavy oil to pass through the
membrane. In
a third embodiment, the membrane is of sufficient pore size for at least 70%
of the
heavy oil to pass through the membrane, In a fourth embodiment, it is of
sufficient
size for at least 75% of the heavy oil to pass through the membrane.
[078] In one embodiment, the filtration medium is a filtration membrane
having an effective pore rating ("average pore size") of about 5 microns or
less is
used; for example, about 0.1-0.3 um, about 0.05-0.15 um, or about 0.1 gm. In a
third
embodiment, an effective pore rating of about 1 micron or less. In a fourth
embodiment, about 0.5 micron or less. In yet a fifth embodiment, the membrane
has
an effective pore rating of at least 0.01 micron. In a sixth embodiment, from
0.1 to 1
micron, In a seventh embodiment, an effective pore rating of at least 1
micron. In an
eight embodiment, an effective pore rating of less than 10 microns.
[079] Polymers, organic materials, inorganic ceramic materials, and metals
are suitable for use as construction materials for the membrane, as long as
they are
solvent stable, The term "solvent-stable" refers to a material that does not
undergo
significant chemical changes to substantially impair the desired properties of
the
material. Stability can be verified by various well-known techniques, which
include,
but are not limited to, soaking test, scanning electron microscopy (SEM), X-
ray
diffraction (XRD), differential scanning calorimetry (DSC) and
thermogravimetric
analysis (TGA).
[080] In one embodiment, the filtration membrane is made of
polytetrafluoroethylene (Teflon ), for example, polytetrafluoroethylene on
woven
fiberglass, which can withstand temperatures of 130 C (266 F). With the use of
polytetrafluoroethylene, the membrane is chemically inert, can handle
continuous pH
levels of 0-14.
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Date Recue/Date Received 2020-08-06
[081] In one embodiment, the filtration membrane comprises a polymeric
material selected from the group of poly(acrylic acids), poly(acrylates),
polyacetylenes, poly(vinyl acetates), polyacrylonitriles, polyamines,
polyamides,
polysulfonamides, polyethers, polyurethanes, polyimides, polyvinyl alcohols,
polyesters, cellulose, cellulose esters, cellulose ethers, chitosan, chitin,
elastomeric
polymers, halogenated polymers, fluoroelastomers, polyvinyl halides,
polyphosphazenes, polybenzimidazoles, poly(trimethylsilylpropyne),
polysiloxanes,
poly(dimethyl siloxanes), and copolymers blends thereof. These polymers can be
physically or chemically cross-linked to further improve their solvent
stability.
[082] In one embodiment, the membrane comprises an inorganic material
such as ceramics (silicumcarbide, zironiumoxide, titaniumoxide, etc,) having
the
ability to withstand high temperatures and harsh environments. In one
embodiment,
the membrane is constructed from a woven fabric coated with a nanomaterial,
e.g., an
inorganic metal oxide, allowing the membrane to be in the form of a flexible
ceramic
membrane foil with advantages of both ceramic and polymeric membranes. In
another embodiment, the filtration membrane is constructed from a metal such
as
stainless steel, titanium, bronze, aluminum or nickel-copper alloy. In yet
another
embodiment, the membrane is constructed from materials such as sintered
stainless
steel with an inorganic metal oxide coating, e.g., a titanium oxide coating.
[083] In one embodiment, the deoiling zone comprises a membrane that is
rapidly displaced in a horizontal direction. A retentate of the membrane
comprises
the fine catalyst and a permeate of the membrane comprises the heavy oil. In
particular, rapidly displacing the membrane in a horizontal direction can
comprise
rotating the membrane.
[084] In one embodiment, filtration membrane operating pressure is in the
range of about 30-100 psi (about 2-7 bar). Filtering can be conducted at a
temperature
of about 50-200 C and a pressure of about 80-200 psi, for example at a
temperature of
about 100 C and a pressure of about 90 psi. In one embodiment, the deoiling
zone
comprising multiple filtration units is operated at a pressure in the range of
about 20-
400 psi, for example, about 30-300 psi or about 50-200 psi. Pressure drops
across the
membrane in the filtration units, referred to as the transmembrane pressure,
are in the
range of about 0-100 psi, for example, about 0-50 psi or about 0-25 psi. In
one
embodiment, the temperature of the deoiling zone is in the range of about 100-
500 F,
for example, about 150-450 F or about 200-400 F.
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Date Recue/Date Received 2020-08-06
[085] Solvent Extraction: In the deoiling zone, an extracting medium is
employed for the extraction / separation of the heavy oil from the spent
catalyst. In
one embodiment, the extraction medium is a light specific gravity solvent or
solvent
mixtures, such as, for example, xylene, benzene, toluene, kerosene, refonnate
(light
aromatics), light naphtha, heavy naphtha, light cycle oil (LCO), medium cycle
oil
(MCO), propane, diesel boiling range material, which is used to "wash" the
feed
stream to the deoiling zone. In one embodiment, the solvent is a commercially
available solvent such as She1SoITM 100 series solvent.
[086] In one embodiment, the washing / mixing with solvent (i.e., solvent
extraction) is done prior to membrane filtration, e.g., in a separate tank
such as a
settling tank / mixing tank prior to the membrane filtration unit. In another
embodiment, the washing / mixing with solvent is in-situ in a membrane
filtration
unit. In one embodiment, a light specific gravity solvent and feed stream
comprising
spent slurry catalyst are supplied in separate stream to one or more
filtration units in a
counter-current fashion. In yet another embodiment, the washing / mixing with
solvent is in a concurrent fashion.
[087] In one embodiment, the solvent can be a recycled solvent (used
solvent) recovered from a process step within the deoiling zone. In another
embodiment a solvent mixture containing at least any two of all the
aforementioned
solvents is used.
[088] In one embodiment, the feedstock stream containing slurry catalyst,
i.e., catalyst particles in heavy oil, is mixed / washed with solvent in a
volume ratio of
ranging from 0.10/1 to 100/1 (based on the spent catalyst slurry volume). In a
second embodiment, the solvent is added in a volume ratio of 0.50/1 to 50/1.
In a
third embodiment, at a volume ratio of 1/1 to 25/1.
[089] In one embodiment, the feedstock stream containing slurry catalyst, is
mixed / washed with a sufficient amount of solvent to reduce the heavy oil
concentration in the feedstock stream by at least 40%. In a second embodiment,
a
sufficient amount of solvent is added to reduce the heavy oil concentration by
at least
50%. In a third embodiment, the heavy oil concentration is reduced by at least
60%.
[090] It is noted that catalyst particles settle significantly faster to the
bottom
(i.e., as in a two phase mixture) with the reduction of the heavy oil
concentration.
Thus in one embodiment, the washing / mixing with solvent is carried out with
the use
of plurality of settling tanks to allow for the settling of the catalyst
particles at the
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Date Recue/Date Received 2020-08-06
bottom, and successive removal of the lighter phase comprising solvent and
portions
of the heavy oil from the settling tanks until most of heavy oil is removed
from the
catalyst particles, leaving a stream consisting mostly of catalyst solids in
light specific
gravity solvent, In another embodiment, settling tanks are used in combination
with
filtration units, e.g., cross-flow filtration, cross-flow sedimentation, etc.
for some of
the heavy oil to be phase-separated from catalyst particles with the use of
the settling
tanks, then for the residual heavy oil to be separated with filtration
technology.
[091] In one embodiment after a sufficient amount of solvent is added to
reduce the heavy oil concentration of at least 50%, the stream comprising
solvent,
catalyst particles and heavy oil is put into a settling tank to allow
separation by
gravity. In one embodiment after successive separation steps with a plurality
of
settling tanks, at least 90% of the heavy oil is removed from the catalyst
particles.
[092] In one embodiment, the mixing of solvent and feedstock is for a
sufficient amount of time and at a temperature sufficient to prevent
substantial
asphaltenes precipitation prior to and during filtration. In one embodiment,
this
temperature ranges from about 50 to I50 C. In one embodiment, the mixing is in
the
range from 15 minutes to an hour. In another embodiment, for at least 20
minutes,
In another embodiment in a continuous process, the mixing of solvent and
feedstock
is less than 10 minutes. In yet another embodiment with the mixing of solvent
and
feedstock being in-situ in a filtering device, the mixing occurs in 5 minutes
or less..
[093] Besides combining / washing the feedstock containing slurry catalyst
in heavy oil with solvent prior to filtering, the retentate of the membrane
from the
filtering process can also be washed with a solvent. After washing in a
filtration unit,
a permeate (filtrate) stream comprising heavy oil and solvent, can be
recovered in
addition to a retentate stream, comprising unsupported fine catalyst and
solvent. The
unsupported fine catalyst can be subsequently separated from the retentate
stream of
the membrane.
[094] In one embodiment, the solvent of the combined retentate-solvent
stream is a different solvent than the solvent of the combined slurry-solvent
stream.
In another embodiment, the solvent for use in the combined retentate-solvent
can be
the same solvent as the solvent of the combined feedstock - solvent stream. In
yet
another embodiment, the solvent can include solvent from a different source
than the
solvent of the combined feedstock - solvent stream.
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Date Recue/Date Received 2020-08-06
[095] In one embodiment, the retentate stream from a first filtration unit can
be combined with solvent prior to a next filtration unit in series, through
which the
combined retentate-solvent stream is filtered, In one embodiment, a permeate
(filtrate) stream of a later-staged filtration unit (in a system with a
plurality of
filtration stages or units) can be recycled to be used as the solvent for use
with the
feed stream entering an earlier staged filtration unit, forming a combined
feedstock -
solvent stream,
[096] In one embodiment, the retentate stream is further diluted with a
solvent rich stream and passed to a succeeding filtration unit. In one
embodiment,
the solvent rich stream is a stream of unconverted oil along with a solvent
such as
toluene, which is passed through the membrane of a succeeding filtration unit.
As the
retentate streams move forward to succeeding filtration units, the retentate
streams
can be sequentially washed counter-currently with toluene rich streams passed
through the membranes of succeeding filtration units.
[097] In one embodiment, the retentate streams are sequentially washed in a
"counter-current" fashion, in that retentate streams pass from one filtration
unit to the
next (e.g., five to six total stages), while the solvent that is added to the
retentate
streams comes from one more downstream filtration units. For example, in an
embodiment, the solvent cascades from the last filtration unit to the first
filtration
unit, counter to the flow of the retentate streams passing through the
filtration units.
In this way, the liquid portion of the feed to the first filtration unit
comprises a
mixture of solvent and unconverted oil, while the liquid portion of the feed
to the last
filtration unit comprises substantially pure solvent, and the retentate stream
of the last
filtration unit comprises the catalyst particles in substantially pure
solvent.
[098] As illustrated in Figures lA ¨ 1 F, the filtration membranes employed
can be fabricated into various forms including a pressure leaf unit (either
horizontal or
vertical type), a plate and frame unit (Figure IA), pleated membrane (Figure
1B), a
tubular / hollow module (1C), a plurality of tubular / hollow modules (Figure
1D), a
spiral wound form (1E), or combinations thereof, e.g., a plurality of tubular
modules
with each being of spiral wound form (not shown).
[099] Figure IA is a cross-section view of a plate and frame (flat plate)
unit.
In one embodiment, the plate and frame (flat plate) unit can take sheet stock
filtration
membranes.
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Date Recue/Date Received 2020-08-06
[0100] In Figure 113, a pleated filtration membrane is interposed between two
permeable sheets and is wound on a core having a plurality of collection
ports. An
outer guard is provided to protect the filtration membrane. The system is
sealed by
end plates at opposite ends of the filer. Heavy oil is collected from the
collection
ports and comes out of the outlet. In one embodiment of the pleated membrane
of
Figure 1B, a sleeve is placed around the cartridge and the housing so as to
withdraw
the retentate stream from the bottom of the housing, the cross-flow stream
being
thereby forced into the pleats where it moves tangential to the membrane.
[0101] Figure 1C illustrates a substantially tubular membrane filter having an
outer housing, an inlet (feed), a retentate outlet and a permeate outlet
(filtrate).
Extending within the housing is at least a tubular filter which is parallel to
the axis of
the housing.
[0102] Figure ID is a second embodiment a tubular filter system with a
plurality of filter sleeves (hollow membrane tubes) running parallel to one
another and
to the axis of the housing.
[0103] Figure 1E illustrates a spiral wound membrane module with alternating
layers of membrane and separator screen being wound around a hollow central
core.
In operation, the feed stream is pumped into one end of the cartridge. The
filtrate
passes through the membrane and spirals to the core of module, where it is
collected
for removal.
[0104] In one embodiment, the filtration assembly in the deoiling comprises a
plurality of filtration units for effective removal of heavy oil from catalyst
particles.
In one embodiment, a filtration assembly with a plurality of filtration units
is capable
of removing most of the heavy oil from catalyst particles, for a filtrate
stream
comprising solvent and at least 90% of the incoming heavy oil (in the feed
stream of
heavy oil and slurry catalyst). In another embodiment, a filtration assembly
with a
plurality of filtration units is capable for removing at least 95% of the
heavy oil from
the catalyst particles. In a third embodiment, up to 99% of the heavy oil is
removed
from the catalyst particles.
[0105] In one embodiment, the filtration assembly comprises between two to
ten filtration units. In another embodiment, at least four to eight filtration
units. In a
third embodiment, the assembly comprises six filtration units. The filtration
units
employed in the deoiling zone can be in any of the form of diafiltration,
cross-flow
filtration, dynamic filtration, cross-flow sedimentation, co-current
sedimentation
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Date Recue/Date Received 2020-08-06
separation, countercurrent sedimentation separation, and combinations thereof,
which
processes are to be described in further detail below.
[0106] In one embodiment of the membrane filtration process, each filtration
unit may comprise a plurality of stages, e.g., at least two stages of cross-
flow
filtration, at least two stages of dialfiltration, or combinations of cross-
flow filtration,
cross-flow sedimentation, co-current sedimentation separation, countercurrent
sedimentation separation, and / or dialfiltration and / or dynamic filtration,
each being
a separate stage. The number of stages of filtration and the solvent to heavy
oil ratio
are set to achieve the required deoiling efficiency.
[0107] Diafiltration. In one embodiment, the membrane filtration is in the
form of diafiltration. In the prior art, diafiltration is typically used for
purifying
retained large molecular weight species, increasing the recovery of low
molecular
weight species, buffer exchange and simply changing the properties of a given
solution. With the fractionation process of diafiltration and with the use of
solvent,
heavy oil molecules are washed through the membrane as filtrate, leaving the
catalyst
solids (particles) in the retentate.
[0108] In one embodiment, diafiltration is in the form of a single stage. In
another embodiment, the diafiltration unit comprises a plurality of stages,
e.g,, at least
several stages in one embodiment, between about 2 and 5 stages in a second
embodiment, and at least 7 in a third embodiment. With the use of
diafiltration, the
fine solid in the slurry catalyst in a first solution (e.g., a heavy bleed oil
or
hydrocarbon solution) is transferred to in a second solution (retentate) along
with a
solvent such as, for example, toluene or light naphtha. Heavy bleed oil is
recovered in
the filtrate stream along with solvent,
[0109] Dynamic Filtration. In one embodiment, one or more filtration units
described above may be replaced by one or more dynamic filtration units.
[0110] Dynamic filtration has been typically employed in treating wastewater
containing particulate matters and waste oils. A dynamic filtration assembly
has the
ability to handle a wide range of materials, to achieve an appreciably high
concentration of retained solids, to be operated continuously over extended
periods
without the need for filter aids and / or backflushing, and to achieve
uniformly high
filter performance to minimize the overall system size. The dynamic filtration
assembly may be of any suitable configuration and will typically include a
housing
which contains a filter unit comprising one or more filtration media and a
means to
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Date Recue/Date Received 2020-08-06
effect relative movement between the filtration medium and the materials to be
filtered. The filtration media of the filter unit and the means to effect
relative
movement between the fluid being filtered and the filtration medium may have
any of
a variety of suitable configurations. A variety of suitable motive means can
be utilized
to carry out such relative motion, such as, for example, rotational,
oscillation,
reciprocating, or vibratory means.
[0111] Variable vibration amplitude and corresponding shear rate, oscillation
frequency, and shear intensity directly affect filtration rates. Shearing is
produced by
the torsion oscillation of the membrane. In one embodiment of a dynamic
filtration
unit, the membrane oscillates with an amplitude of about 1.9-3.2 cm peak to
peak
displacement at the edge of the membrane. Optimal filtration rates can be
achieved at
high shear rates, and, since the concentrate is not degraded by shear, maximum
shear
is preferred, within practical equipment limitations. In one embodiment, a
dynamic
filtration unit creates shear forces of at least about 20,000 sec-1. In a
second
embodiment, at least about 100,000 seel. In another embodiment, the
oscillation
frequency is about 50-60 Hz, for example, about 53 Hz, and produces a shear
intensity of, for example, about 150,000 sec-1. In yet another embodiment, a
shear
force between 20,000 and 100,000 sec-1.
[0112] In one embodiment, the dynamic filtration assembly operates with
relatively low cross-flow velocities, thus preventing a significant pressure
drop from
the inlet (high pressure) to the outlet (lower pressure) end of the device,
which can
lead to premature fouling of the membrane that creeps up the device until
permeate
rates drop to unacceptably low levels.
[0113] In one embodiment, operating pressure in a dynamic filtration
assembly is created by the feed pump. While higher pressures often produce
increased permeate flow rates, higher pressures also use more energy.
Therefore, the
operating pressure optimizes the balance between flow rates and energy
consumption.
[0114] The dynamic filtration assembly may be of any suitable device.
Suitable cylindrical dynamic filtration systems are described in U.S. Pat.
Nos.
3,797,662, 4,066,554, 4,093,552, 4,427,552, 4,900,440, and 4,956,102. Suitable
rotating disc dynamic filtration systems are described in U.S. Pat. Nos.
3,997,447 and
5,037,562, as well as in U.S. patent application Ser. No, 07/812,123. Suitable
oscillating, reciprocating, or vibratory dynamic filtration assemblies are
generally
described in U.S. Pat. Nos. 4,872,988, 4,952,317, and 5,014,564. Other dynamic
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Date Recue/Date Received 2020-08-06
filtration devices are discussed in Murkes, "Fundamentals of Crossflow
Filtration,"
Separation and Purification Methods, 19(1), 1-29 (1990). In addition, many
dynamic
filtration assemblies are commercially available. For example, suitable
dynamic
filtration assemblies include Pall BDF-LAB, ASEA Brown Bovery rotary CROT
filter, and New Logic V-SEP.
[0115] In one embodiment, the dynamic filtration unit employed is
exemplified by a Vibratory Shear Enhanced Processing (V*SEP) system from New
Logic. In a V*SEP system, a membrane module is used for separation, and
wherein
intense shear waves are imposed on the face of the membrane. V*SEP systems
have
been typically employed in treating wastewater containing particulate matters
and
waste oils. In one embodiment of the invention, V*SEP is used in the deoiling
process.
[0116] In one embodiment, the use of dynamic filtration allows for the same
separation efficiency to be achieved with fewer filtration stages. In
particular, while
typical cross-flow filters are usually limited to solids contents of 25-35
weight % to
avoid fouling of the membrane, dynamic filtration machines can accept higher
solids
contents (50-70 weight %) while maintaining performance, Accordingly, the use
of
dynamic filtration allows for greater oil removal per stage in diafiltration
mode, which
would reduce the required number of stages.
[0117] In a dynamic filtration unit, a slurry to be filtered remains nearly
stationary, moving in a leisurely, meandering flow. Shear cleaning action is
created
by rapidly (i.e., 50-60 Hz) horizontally displacing the membrane (i.e., in
directions in
the same plane as the face of the membrane). In an embodiment, the
displacement is
rotational or oscillatory. The shear waves produced by the displacement, or
vibration,
of the membrane cause solids and foulants to be lifted off the membrane
surface and
remixed with the slurry and expose the membrane pores for maximum throughput.
[0118] In an embodiment, dynamic filtration is used to aid in the transport of
catalyst (slurry) prior to heavy oil upgrading. In yet another embodiment,
dynamic
filtration is used to concentrate catalyst slurry to a solids contents of, for
example,
about 60-70 weight %. Due, in part, to the concentrated catalyst slurry having
a
reduced volume as compared to the volume of the catalyst slurry prior to
concentration via dynamic filtration, the concentrated catalyst slurry can
then be more
easily transported to a heavy oil upgrading site or reactor, where it would be
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Date Recue/Date Received 2020-08-06
reconstituted to a solids contents of, for example, about 5 weight %, prior to
heavy oil
upgrading.
[0119] Sedimentation Separation. In one embodiment, the membrane
filtration is in the form of a sedimentation separator, In sedimentation
separation, the
membrane is in the form of a plurality of channels arranged in parallel, and
wherein
the channels are inclined downward to facilitate sedimentation. In one
embodiment,
the channels are in the form of a pleated membrane, e.g., a V-shape, a U-
shape, etc.
In another embodiment, the channels are in the form of tubes having
elliptical, square,
rectangular, or circular cross-sectional area. The term "channel" may be used
interchangeably with "tube." In one embodiment, the sedimentation separator
further
comprises a receiving chamber (a sedimentation container) for receiving the
retentate.
[0120] In one embodiment, the filter system has tube diameters or channel
heights of 100 mm or less, a length of approx. 0.2 to 2.5 m and an angle of
inclination
at least 45 from a horizontal surface. In a second embodiment, the angle of
inclination ranges from 45 to 75 . In yet another embodiment, the tubes (or
channels) have a length in the range from 0,2 to 1.5 m. In a fourth
embodiment, the
filter system has an angle of inclination from a horizontal surface in the
range of 30 to
60 .
[0121] The tubes can be of any shape or form. In one embodiment, the
membrane filter is in the form of a plurality of channels having a rectangular
cross
section. In yet another embodiment, the membrane filter is in the form of a
plurality
of round tubes (circular cross-section area). In one embodiment, the tubes (or
channels) have uniform cross-section areas, In another embodiment, the cross-
sectional areas vary depending on the location of the tubes.
[0122] In one embodiment of a membrane sedimentation system, the
apparatus comprises a module comprising the tubes (or channels), a covering
plate
and a return vessel (located beneath the inclined channels) for the collection
of the
filtrate. In one embodiment, the apparatus further comprises inflow and
outflow
chamber plates to improve the flow distribution. The plates can be either flat
plates
or shaped. In one embodiment, the plates are arranged in close proximity and
perpendicular to the inflow and outflow channels.
[0123] The membrane sedimentation separator for use in the deoiling zone can
be in any of the form: counter-current sedimentation separator (as illustrated
in
Figure 2), cross-flow sedimentation separator (as illustrated in Figure 3),
and co-
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Date Recue/Date Received 2020-08-06
current sedimentation separator (not shown). As shown in Figure 2 of an
embodiment of counter-current sedimentation separation, the solvent stream and
feed
stream comprising slurry catalyst in heavy oil are provided to the receiving
chamber
as two separate opposite (counter-current) flows. Figure 3 illustrates an
embodiment
of a cross-flow sedimentation separator, with the inlet comprising solvent,
slurry
catalyst in heavy oil entering one side of channels and an outflow for the
filtrate
(comprising heavy oil and solvent) on the opposite side of the channel, A
pyramidal
receiving chamber is located beneath the channels for the collection of the
retentate
(comprising slurry catalyst and solvent).
[0124] In one embodiment, the membrane filtration system comprises a
plurality of different or the same sedimentation separators, e.g., two cross-
flow
sedimentation separators in series, a dynamic filtration system in series with
a
counter-current sedimentation separator, or a combination of cross flow
sedimentation, co-current sedimentation, conventional settling tank, inclined
settler
with a dynamic filtration system (a vibratory separation device), as long as
the
vibration from the dynamic filtration unit is not transmitted to the settler /
sedimentation unit.
[0125] In one embodiment, a feed stream to the membrane filtration unit
containing 60 ¨ 95 wt. % heavy oil and 5-40 wt. % spent catalyst (as solids,
in the
form of slurry catalyst) may exit the filtration unit as a retentate stream
containing 5-
40 wt, % catalyst (as solids), 0.01 to 1 wt, % heavy oil, and with the
remainder as
solvent. In a second embodiment, the retentate stream exiting membrane
filtration
may contain anywhere from 0.05 to .5 wt. % heavy oil, on a solvent-free basis.
In a
third embodiment, the amount of heavy oil remaining in the retentate ranges
from 0.1
to 0.3 wt, %.
[0126] In the deoiling zone, the slurry catalyst in heavy oil is solvent
washed
and separated in mixed stream is solvent washed in a deoiling zone and
transferred
from a heavy, USBO into a low boiling range solvent. The products from the
deoiling
zone include a stream with the catalyst and a higher percentage of solvent and
a
stream without catalyst and with a relatively high percentage of USBO. From
the
deoiling zone a stream consisting of solvent and carrier oil mixture is routed
to a
splitter column, which produces an overhead stream of solvent, which is
recirculated
to solvent tankage for use in the washing process, and a bottoms stream of
carrier oil,
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Date Recue/Date Received 2020-08-06
which is sent to product recovery, a hydroprocessing section, or to another
residue
disposition unit.
[0127] In one embodiment after membrane filtration (e.g., filtration using any
of cross-flow filtration, diafiltration, dynamic filtration, etc.), the
filtrate product
comprising solvent and heavy oil mixture is routed to a separator, e.g., a
splitter
column, for the separation and subsequent recovery of solvent and heavy oil,
Solvent
(and any residual heavy oil) can be subsequently separated from the catalyst
particles
in the retentate stream using various separation means including drying,
detergent
washing, ultrasonic cleaning, plasma cleaning, and the like. In one
embodiment, the
retentate stream comprising mostly slurry catalyst in solvent can be sent to a
drying
zone.
[0128] In one embodiment, the splitter column produces an overhead stream
of solvent which can be rerouted to a solvent tank for re-use in the solvent
washing
process, and a bottoms stream of carrier oil (unconverted heavy oil and
heavier
hydrocracked liquid products) which can be sent to product recovery, a
hydroprocessing unit, or a residue disposition unit.
[0129] Drying Zone: The retentate (bottoms) stream consisting of highly
concentrated spent catalyst in solvent in one embodiment is sent to a drying
zone for
final devolatilization. Deoiling followed by drying allows for production of a
sufficiently hydrocarbon-dry material to meet downstream metals recovery
requirements.
[0130] In one embodiment, the feed stream to the drying zone comprises
between 50 to 90 wt. % hydrocarbons, and the remainder being catalyst
particles.
Most of the hydrocarbons are in the form of solvent, and with residual heavy
oil
making up less than 5 wt. % of the total stream in one embodiment, less than 3
wt. %
in another embodiment, and less than 0.1 wt. % in yet another embodiment.
[0131] In one embodiment, the drying step can involve, for example,
evaporation at ambient conditions, warming in a dryer, or processing through a
robust
thin-film (or wiped-film) combination type dryer or evaporator. In another
embodiment, the drying step utilizes an apparatus that would convert the
catalyst to a
free-flowing granular state with a minimum time of exposure to heat and
vacuum,
e.g., a nitrogen charged furnace. In one embodiment, the drying apparatus is
selected
from an indirect fired kiln, an indirect fired rotary kiln, an indirect fired
dryer, an
indirect fired rotary dryer, an electrically heated kiln, an electrically
heated rotary
- 25 -
Date Recue/Date Received 2020-08-06
kiln, a microwave heated kiln, a microwave heated rotary kiln, a vacuum dryer,
a thin
film dryer, a flexicoker, a fluid bed dryer, a shaft kiln dryer or any such
drying device.
Retentate stream from the filtration unit can be fed to the drying apparatus
either co-
currently or counter-currently with the gas feed, which can be oxidative,
reducing, or
inert gas.
[0132] In one embodiment, the drying apparatus is a thin film dryer, a thin-
film evaporator, a wiped film dryer, or a wiped-film evaporator, which is
efficient in
rapidly exposing the surfaces of the catalyst particles to the heat transfer
medium. In
one embodiment, the drying apparatus is a vertical thin-film dryer, a vertical
thin-film
evaporator, a vertical wiped-film dryer, or a vertical wiped-film evaporator.
In
another embodiment, the apparatus is a horizontal thin film dryer, a
horizontal thin-
film evaporator, a horizontal wiped-film dryer, or a horizontal wiped-film
evaporator.
In a third embodiment, the apparatus is a Combi dryer (combining vertical and
horizontal designs) from LCI Corporation. The thin film or wiped-film dryer /
evaporator can be operated in batch or continuous modes with a wide range of
residence times depending on the configuration of the dryer,
[0133] In one embodiment, the drying apparatus is a rotary kiln dryer, which
can be either a rotating inclined cylinder or a rotating heat exchanger. In
one
embodiment, the rotary kiln is one of a direct fired rotary kiln, an indirect
fired rotary
dryer, an electrically heated rotary kiln, and a microwave heated rotary kiln.
Residence time in the rotary kiln dryer depends on the dimension of the kiln,
and
varies from 2 to 250 minutes.
[0134] In one embodiment, the drying treatment of spent catalyst is at
atmospheric pressure. In a second embodiment, at a pressure from 0 to 10 psig.
In
one embodiment, the drying is done under an inert condition, e.g,, nitrogen,
at a
nitrogen flow ranging from 0.2 to 5 scf/min. In one embodiment, the nitrogen
flow
ranges from 0.5 to 2 scf/min. Other general conditions, i.e., temperature and
residence time, can be varied accordingly for organic matters to be evaporated
from
the catalyst. In one embodiment, the residence time in the drying apparatus
ranges
from 5 minutes to 240 minutes. In a second embodiment, from 10 to 120 minutes.
In a third embodiment, at least 15 minutes. In a fourth embodiment, in the
range of
30 ¨ 60 minutes. With respect to the treatment temperature, it can be varied
according to the type of apparatus used, the applied pressure and the level of
heavy oil
and solvent remaining in the spent catalyst. In one embodiment with the use of
a
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Date Recue/Date Received 2020-08-06
vertical thin-film dryer, the temperature is generally in the range of 300 to
450 F (149
to 232 C). In a second embodiment with the use of a horizontal thin-film
dryer, the
temperature is in the range of 400¨ 700 F (204 to 371 C). In a third
embodiment
with the use of rotary kiln dryer, the temperature is in the range of 700 to
1200 F (371
to 649 C). In a fourth embodiment, the drying temperature is at a sufficiently
high
temperature to decompose at least 90% of the carboxylates, i.e., surface
active
hydrocarbon compounds that may be bound to the catalyst particles. In a fifth
embodiment, at least 95% of the carboxylates are removed with the use of the
dryer.
[0135] In one embodiment, the drying step involves at least a two-stage drying
process, with the 2I'd drying stage is for the removal of contaminants, e.g.,
carboxylates, residual oil in the pore space of the spent catalyst, etc,,
volatilizing the
organic compounds for removal. In one embodiment, the retentate stream from
the
deoiling zone containing highly concentrated spent catalyst in solvent is
first fed into
a rotary drum dryer (operating at a temperature of less than 200 C) before
going into a
rotary kiln dryer (operating at a temperature greater than 300 C), with a
rotation
ranging from 0.5 to 10 rpm and a retention time ranging from 5 to 200 minutes.
The
feed rate to the kiln is based on the diameter of the kiln. In one embodiment
with the
use of a 6" diameter kiln, the feed rate to the kiln ranges from 2 to 10 lbs.
of solid per
hour. In another embodiment with a 18" kiln, the feed rate ranges from 10 to
300 lbs.
of solid materials per hour.
[0136] In yet another embodiment, the retentate stream is first dried in a
Combi dryer with an operating temperature in the range of 200 to 450 F (93 to
232 C) in the vertical section, a temperature in the range of 400 - 900 F (204
to
482 C) in the first half of the horizontal section, and with a temperature in
the last half
of the horizontal section (or the cooling section) in the range of 50-100 F
(10 to
38 C). Temperature of the stream exiting the Combi drier in one embodiment
ranges
from 80 to 120 F (27 ¨ 49 C).
[0137] In one embodiment, the drying zone comprises a plurality of drying
apparatuses to maximize the removal of contaminants, e.g,, carboxylates,
residual oil
in the pore space of the spent catalyst, etc. In one embodiment, the retentate
stream
from the deoiling zone is first fed into a Combi dryer, wherein most of the
solvent is
removed, for EU 1 exit stream consisting essentially of catalyst (as a dry
powder) and
residual heavy oil (ranging from 0,1 to I wt.% in one embodiment, and less
than 0,5
wt.% in a second embodiment). The Combi dryer in one embodiment is maintained
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Date Recue/Date Received 2020-08-06
under a blanket of nitrogen, with nitrogen provided as a counter-current flow
in an
amount ranging from 0.2 to 5 scf/min. This dry powder in next sent to a 2"
drying
stage in a rotary kiln dryer, wherein residual organic materials, e.g., heavy
oil, is burnt
off, In the rotary kiln, nitrogen can be supplied as co-current or counter-
Current flow.
The residence time in the 2" stage ranges from 10 to 150 minutes in one
embodiment.
[0138] The volatized organic compounds after leaving the catalyst particles
can be collected in condensers, wherein the heavy oil and / or solvents can be
recovered.
[0139] Detergent Washing: In one embodiment, instead of or in addition to a
drying unit for the removal of solvent / residual heavy oil in the catalyst
(after
membrane filtration), a surfactant is used to remove solvent and / or heavy
oil bound
to the catalyst. The surfactant solution is added to the retentate stream out
of the
membrane filtration unit. In another embodiment, the surfactant solution is
added to
the stream containing catalyst particles and hydrocarbons, i.e., solvent plus
residual
heavy oil, out of the drying zone.
[0140] In a vessel, e.g., a mixing tank with mechanical agitation, the
surfactant attracts solvent / any residual heavy oil away from the spent solid
catalyst
with its hydrophilic head that is attracted to water molecules and hydrophobic
tail that
repels water and attaches itself to the solvent and heavy oil. The opposing
forces
loosen / remove the solvent and heavy oil from the solid catalyst. The mixing
of the
cleaning solution containing surfactants and the mixture of spent catalyst and
hydrocarbons is for a sufficient amount of time and under conditions
sufficient to
remove the hydrocarbons from the catalyst surface into the aqueous solution.
The
mixture of surfactant / solvent / heavy oil in water can be subsequently
separated from
the solid catalyst through separation means known in the art, including but
not limited
to decantation and the use of settling tanks.
[0141] In one embodiment, the mixing temperature is in the range of about
C. to 85 C. In a second embodiment, the mixing is at a temperature of less
than
85 C. In a third embodiment, at a temperature of up to 177 C. In one
embodiment,
30 the mixing (contacting) of the cleaning solution and the mixture of
spent catalyst and
hydrocarbons is for at least two minutes. In a second embodiment, for at least
5
minutes, In a third embodiment, for at least 10 minutes.
[0142] In one embodiment, the surfactant is first dissolved in water, e.g.,
deionized water, in a concentration between about 0.001% and saturation. In a
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Date Recue/Date Received 2020-08-06
second embodiment, the surfactant is added in a concentration between 0.01% to
about 10%. In a third embodiment, at a concentration between 0.5% to about 5%.
In
a fourth embodiment, at a concentration sufficient to dissolve and remove at
least 90
wt. % of the hydrocarbons, i.e., solvents and heavy oil, from the surface of
the
catalyst particles. In a fifth embodiment, the concentration of the surfactant
is
sufficient to dissolve and remove at least 95 wt. % of the hydrocarbons from
the
catalyst particles.
[0143] In one embodiment, the surfactant is selected from the group of
anionic, nonionic, zwitterionic, acidic, basic, arnphoteric, enzymatic, and
water-
soluble cationic detergents and mixtures thereof. In one embodiment, the
surfactant is
an anionic detergent.
[0144] In one embodiment, the detergent is an anionic surfactant selected
from water-soluble salts, particularly the alkali metal, ammonium and
alkanolarrunonium salts, of organic sulfuric reaction products having in their
molecular structure an alkyl group containing from about 8 to about 22 carbon
atoms
and a sulfonic acid or sulfuric acid ester group. (Included in the term
"alkyl" is the
alkyl portion of acyl groups.) Examples of this group of synthetic surfactants
include
sodium and potassium alkyl sulfates, especially those obtained by sulfating
the higher
alcohols (C8-C18 carbon atoms) produced by reducing the glycerides of tallow
or
coconut oil, sodium and potassium C8-C20 paraffin sulfonates, and sodium and
potassium alkyl benzene sulfonates, in which the alkyl group contains from
about 9 to
about 15 carbon atoms in straight chain or branched chain configuration.
[0145] In another embodiment, the anionic surfactant compound is selected
from the group of sodium alkyl glyceryl ether sulfonates, and sodium or
potassium
salts of alkyl phenol ethylene oxide ether sulfate containing about 1 to about
10 units
of ethylene oxide per molecule and wherein the alkyl groups contain about 8 to
about
12 atoms. In yet another embodiment, the anionic surfactant is selected from
sodium
linear Cio-C12 alkyl benzene sulfonate; triethanolamine C10-Ci2 alkyl benzene
sulfonate; sodium tallow alkyl sulfate; sodium coconut alkyl glyceryl ether
sulfonate;
and the sodium salt of a sulfated condensation product of tallow alcohol with
from
about 3 to about 10 moles of ethylene oxide; mixtures of sodium and potassium
alkyl
sulfates
- 29 -
Date Recue/Date Received 2020-08-06
[0146] In one embodiment, the surfactant is a nonionic surfactant, Examples
include the water-soluble ethoxylates of C10-C20 aliphatic alcohols and C6-C2
alkyl
phenols.
[0147] In one embodiment, the surfactant is a semipolar surfactant. Examples
include water-soluble amine oxides containing one alkyl moiety of from about
10 to
28 carbon atoms and 2 moieties selected from the group consisting from 1 to
about 3
carbon atoms; water-soluble phosphine oxides containing one alkyl moiety of
about
to 28 carbon atoms and 2 moieties selected from the group consisting of alkyl
groups and hydroxyalkyl groups containing from about 1 to 3 carbon atoms; and
10 water-soluble sulfoxides containing one alkyl moiety of from about 10 to
28 carbon
atoms and a moiety selected from the group consisting of alkyl and
hydroxyalkyl
moieties of from 1 to 3 carbon atoms.
[0148] In one embodiment, the surfactant is an amholytic surfactant.
Examples include derivatives of aliphatic or aliphatic derivatives of
heterocyclic
secondary and tertiary amines in which the aliphatic moiety can be straight
chain or
branched and wherein one of the aliphatic sub stituents contains from about 8
to 18
carbon atoms and at least one aliphatic substituent contains an anionic water-
solubilizing group.
[0149] In yet another embodiment, the surfactant is a zwitterionic surfactant.
Examples include derivatives of aliphatic quaternary ammonium, phosphonium and
sulfonium compounds in which the aliphatic moieties can be straight or
branched
chain, and wherein one of the aliphatic substituents contains from about 8 to
18
carbon atoms and one contains an anionic water-solubilizing group.
[0150] It is further envisaged to use common surfactants including but not
limited to vegetable derived surfactants; household detergents including
natural oils
such as orange oils, citrus oils, etc.; commercially available degreasers; and
common
laboratory surfactants and detergents, e.g., alkyl sulphates, alkyl ethoxylate
sulphates.
In one embodiment, the surfactant is sodium laureth sulfide (SDS), Brij
detergents
and niaproff anionic detergents. In another embodiment, the anionic detergent
is a
proprietary blend of sodium linear alkylaryl sulfonate, alcohol sulfate,
phosphates and
carbonates commercially available as known as ALCONOXTM. In yet another
embodiment, the surfactant is a commercially known detergent by the name of
LIQUINOX TM.
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Date Recue/Date Received 2020-08-06
[0151] It is further envisaged that surfactants do not have to be added as a
cleaning solution. In one embodiment, the surfactant solution is generated in-
situ
with the addition of precursor materials, e.g., alkali metal compounds such as
sodium
hydroxide, ammonium hydroxides, etc., such that at least a surfactant is
generated in-
situ for use in the detergent washing process.
[0152] Ultrasonic Cleaning: In one embodiment, instead of or in addition to
the use of detergent for the cleaning / removal of solvent and heavy oil from
the spent
catalyst, ultrasonic cleaning is employed. Ultrasonic cleaning herein involves
the use
of high-frequency sound waves (above the upper range of human hearing, or
about 18
kHz). In one embodiment, ultrasonic transducers are employed with a frequency
ranging from 20 to 80 kHz. In a third embodiment, the frequency employs ranges
from 15-400 kHz, The ultrasonic tank in one embodiment is maintained at a
temperature of at least 50 C in one embodiment, and at least 70 C in a second
embodiment, up to a temperature of at least 6 C below the boiling point of the
solvent
still remaining with the spent catalyst.
[0153] In one embodiment, ultrasonic / acoustic energy is applied to the
cleaning solution for less than 15 minutes. In one embodiment, from 0.25 to 10
minutes, In a third embodiment, for less than 60 minutes. In one embodiment
the
organic components such as solvent and heavy oil attached to the catalyst
particles are
fully dislodged from the surfaces with the implosion of the bubbles initiated
by the
ultrasonic energy. In a subsequent separation process, e.g., a cyclone, a
decanter or
settling tank, the deoiled fine catalyst particles can be separated and
collected from
the bottom. The aqueous phase containing solvent and heavy oil can be sent to
a
water treatment apparatus, wherein the fraction enrich with organic matters
can be
recovered and water can be recirculated as clean water to the detergent
washing
process. It is also possible to clean the waste water by ultrafiltration,
adsorption
column or other means before it is reused as wash water in the detergent
washing
process,
[0154] Plasma Cleaning: In one embodiment, instead of or in addition to
ultrasonic cleaning or using at least a surfactant for the cleaning / removal
of solvent
and heavy oil from the spent catalyst, plasma cleaning is employed. In some
embodiments, it is advantageous to use a plasma system as compared to a
convention
dryer is that a typical plasma jet is at much higher temperature than a
typical oil or gas
burner. Therefore the heat transfer, dependent on the temperatures of the
energy
- 31 -
Date Recue/Date Received 2020-08-06
source and the heated substance, can be higher in a plasma process, increasing
the
energy efficiency of the plasma process.
[0155] In one embodiment, the plasma cleaning process operates at a
temperature between 400 to 900 C (752 to 1652 F) in order to volatize the
residual
hydrocarbons, i.e., heavy oil residues and solvent, in the catalyst particles.
The
volatized organic compounds after leaving the catalyst particles can be
collected in
condensers, wherein the heavy oil and / or solvents can be recovered. The
plasma
reactor / vessel can be maintained under an inert blanket or reducing
atmosphere to
allow the recovery of the organic materials after volatilizing them in the
plasma
reactor as effluent gases, leaving behind the catalyst particles as dry powder
containing less than 0.5 wt. % hydrocarbons as solvent materials and / or
residual
heavy oil.
[0156] In one embodiment, the plasma cleaning system comprises a vessel
(e.g., a mixing tank or a reactor), a plasma system for heating the mixture of
catalyst
particles and hydrocarbons within the vessel, and means for collecting the
effluent
gases. In one embodiment, the plasma system comprises graphite electrodes and
electric arcs maintained between the graphite electrodes. In another
embodiment, the
plasma system comprises a plurality of plasma torches located within the
vessel
reactor. In one embodiment, a condenser system is employed to collect and
recover
the volatized hydrocarbons. In yet another embodiment, a splitter column is
employed to collect and separate solvents from residual heavy oils in the
volatized
hydrocarbons collected from the plasma system.
[0156] Reference will be made to the figures to further illustrate
embodiments of the invention.
[0157] In one embodiment of a deoiling zone as illustrated in Figure 4,
feedstock stream 1 to deoiling zone 200 enters slurry drum 100 where feedstock
1 is
stored and continuously mixed by slurry pump 150. Feedstock 1 leaves slurry
drum
100 via line 2 and passes to slurry pump 150, which pumps feedstock 1 up to
the
operating pressure of deoiling zone 200. A portion of the feedstock in line 2
is
recycled to slurry drum 100 through line 3 to agitate the feedstock and
prevent
agglomeration of the catalyst particles in slurry drum 100. A main portion of
the
feedstock in line 2 continues to deoiling zone 200, but just before entering
deoiling
zone 200, feedstock 1 is mixed with a light hydrocarbon solvent 4, for
example, a
- 32 -
Date Recue/Date Received 2020-08-06
toluene rich stream, to dilute the unconverted resid hydrocarbon oil and form
stream
5, which is fed to deoiling zone 200.
[0158] In one embodiment, the light hydrocarbon solvent 4 is toluene. In
deoiling zone 200, unconverted oil is removed from the catalyst particles of
stream 5,
leaving stream 6 consisting essentially of unconverted oil in the light
hydrocarbon
solvent, e.g., toluene. Stream 6 is sent to heat exchanger 250 to form heated
stream 7,
which enters separator 300 where flashed off overhead is toluene vapor stream
8 and
unconverted oil is removed as stream 9. In an embodiment, separator 300 is a
distillation column, in order to achieve a sharp separation between solvent
and
recovered oil. Stream 9 comprising unconverted oil can be recycled to the
heavy oil
upgrade process, e.g., a vacuum resid unit, for further processing or sent to
product
storage, Stream 14 from the deoiling zone 200 consists of catalyst particles,
carbon
fines, and metal fines less stream 6 consisting of unconverted oil in toluene.
Stream
14 proceeds to drying zone 500 where toluene vapor stream 16 is separated from
catalyst, carbon fines, and metal fines (i.e., hydrocarbon-free solids) in
stream 17.
The drying zone can be evaporation and solids devolatilization equipment known
to
those skilled in the art. In one embodiment (not shown), stream 17 is routed
to a
metal recovery system wherein the metals in the catalyst can be recovered and
subsequently used in a catalyst synthesis unit,
[0159] Toluene vapor streams 8 and 16 are combined into composite toluene
vapor stream 31, which enters condensing unit 350 where the toluene is
converted
from a vapor state to a liquid state and leaves the condensing unit as liquid
toluene
stream 11. Liquid toluene stream 11 enters solvent storage drum 400, from
which
toluene is recycled to the deoiling zone 200 via line 13. Make-up toluene
stream 12 is
added to solvent storage drum 400, since a small amount of toluene is lost
through
vaporization,
[0160] In yet another embodiment of a deoiling system as illustrated in Figure
5, stream 14 from the deoiling zone 200, consisting of catalyst particles,
carbon fines,
and metal fines less stream 6, can be sent to slurry concentration zone 550,
from
which a portion of stream 14 (stream 19) is fed to drying zone 500 and a
portion of
stream 14 is fed via line 18 to be mixed into toluene vapor stream 16 from
drying
zone 500.
[0161] In another embodiment as illustrated in Figure 6, before the feedstock
stream (containing spent catalyst in heavy oil) 1 is mixed with light
hydrocarbon
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Date Recue/Date Received 2020-08-06
solvent 4, line 2 can be fed to slurry concentration zone 600, from which
unconverted
oil 21 is removed. Stream 22 (i.e., feedstock 1 less unconverted oil 21) is
then be
mixed with light hydrocarbon solvent 4 and fed to deoiling zone 200.
[01621] Figure 7 illustrates the deoiling system as illustrated in Figure 2,
which further contains a slurry concentration zone 550 (as illustrated in
Figure 5) and
the slurry concentration zone 600 of Figure 6.
[01622] With reference to Figure 8, feedstock 51 is mixed with light
hydrocarbon solvent 54 to thin.' stream 55, which is fed to a first filtration
unit
consisting of membrane 215 separating top section 210A and bottom section
210B.
Typically, stream 55 enters the tube side of a multi-tube bundle of membrane
elements with the permeate stream 56 exiting the shell side of the membrane
housing.
In the description that follows, light hydrocarbon solvent 54 is a toluene
rich stream
(i.e., permeate from the second stage of filtration). Slurry pump 230
maintains a
constant velocity in the tubes, preventing settling or agglomeration of
catalyst
particles. A portion of unconverted oil along with toluene passes through
membrane
215 to bottom section 210B and out of the first filtration unit as stream 56
and can be
sent to a distillation process to recover toluene and unconverted oil as
separate
streams. Retentate stream 57 is diluted with a toluene rich stream 58 to form
stream
59, which is passed to a second filtration unit. The second filtration unit
consists of
membrane 225 separating top section 220A and bottom section 220B. Slurry pump
maintains a constant velocity in top portion 220A above membrane 225 and keeps
stream 59 in continuous motion, preventing settling or agglomeration of
catalyst
particles. A portion of unconverted oil along with toluene passes through
membrane
225 to bottom section 220B and out of the second filtration unit as stream 54,
which is
recycled to be mixed with feedstock 51 to form stream 55.
[01623] Figure 9 illustrates an embodiment of a deoiling zone with the use of
a settling tank system 70 for pre-mixing / washing of the catalyst slurry from
a heavy
oil upgrade system. Solvent feed to the settling tank can be recycled solvent
from
any of the drying zone 20 or the solvent recovery system 50. In one
embodiment, a
portion (or all) of the filtrate from the filtration unit is recycled back to
the settling
tank 70 as shown. In another embodiment, a portion (or all) of the retentate
is
recycled back to the settling tank 70 as shown. In yet another embodiment (not
shown), recycled solvent from the recycling zone can also be diverted to the
settling
tank for use in washing the feed stream comprising slurry catalyst in heavy
oil.
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Date Recue/Date Received 2020-08-06
[0165] Figure 10 illustrates an embodiment of a system with a two-staged
drying zone. The first drying zone can be any of a rotary dryer, a vertical
thin-film
dryer, a horizontal thin-film dryer, or a Combi dryer (combination of both
vertical and
horizontal). As shown, the filtrate from the membrane filtration unit
comprising
solvent and heavy oil is passed on to a solvent recovery unit. In this unit,
the solvent
is condensed into a liquid stream and passed on to a solvent tank. In one
embodiment, the solvent recovery unit comprises a distillation column to
achieve a
sharp separation between solvent and heavy oil. Heavy oil can be recycled to a
vacuum resid unit for further processing or sent to product storage. In the 1
drying
stage 20, a retentate stream 2 from the filtration unit is substantially
concentrated, e.g.,
for a stream containing less than 0,2 wt. % heavy oil, up to 90 wt. % solvent
and the
remainder solid catalyst to transform into substantially dry powder form, with
up to 1
wt, % heavy oil. Solvent vapor stream can be recovered (condensed) and
recycled
back to the membrane filtration unit or a settling tank (not shown) for mixing
with the
feed stream to the filtration unit.
[0166] In the 2" drying stage, e.g., a rotary kiln dryer, organic matters are
substantially evaporated for a stream consisting essentially of dry spent
catalyst
powder including metal and carbon fines.
[0167] Metal Recovery from Dry Powder Catalyst: In one embodiment, the
dry spent catalyst powder is sent to a metal recovery unit for recovery of
valuable
metals such as molybdenum, nickel, chromium, etc, for subsequent re-use in a
catalyst
synthesis unit. In one embodiment, the deoiled and dried spent catalyst
particles first
leached with an aqueous solution containing ammonia and air in an autoclave,
i.e., a
multi-chambered, agitated vessel at a sufficient temperature and pressure, in
which
ammonia and air are supplied to induce leaching reactions, wherein the group
VIB
(e.g., molybdenum) and group VIII metals (e.g., nickel) are leached into
solution
forming group VIB and group VIII soluble metal complexes.
[0168] The leached slurry is subsequently subject to liquid-solid separation
via physical methods known in the art, e.g., settling, centrifugation,
decantation, or
filtration, and the like, into a liquid stream containing the group VIB and
VIII metal
complexes ("PLS" or pressure leached solution) and a solid residue comprising
coke
and any group VB metal (vanadium) complex. Following liquid-solid separation,
the
pH of the PLS stream controlled to a level at which selective precipitation of
the
metal complexes occurs ("pre-selected pH"), allowing the precipitation of at
least
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90% of the Group VIB metal, at least 90% of the Group VIII metal, and at least
40%
of the Group VB metal initially present prior to the precipitation. In one
embodiment, the metal complexes undergo further treatment / pre-selective pH
conditioning to further recover the Group VIB and Group VIII metals as metal
sulfides, which can be subsequently used in a catalyst synthesis unit.
[0169] EXAMPLES. The following illustrative examples are intended to be
non-limiting.
[0170] Cross-flow Filtration Example. A feedstock of used resid
hydroprocessing slurry phase catalyst (1 to 10 pm) in unconverted heavy oil
product
was processed using eight stages of cross-flow filtration. The cross-flow
filtration
was conducted at 175 C and 75 psig. The feed slurry solids content was 12
weight%.
In each stage the feed oil was diluted with an amount of toluene equal to the
original
feed slurry. The resulting mixture was circulated through the cross-flow
filtration
module until sufficient oil and toluene permeated through the membrane to
create a
reconcentrated slurry of 25 weight% solids. A recirculating pump maintained a
sufficient velocity through the tubes of the filter housing (greater than 10
feet/second)
to avoid membrane fouling.
[0171] The design of the membrane was such that only the oil could permeate
through the walls of the tube into the shell side of the bundle while the fine
solid
catalyst was retained on the tube side. By repeating this process an
additional seven
times the catalyst was transferred into a substantially oil-free toluene
stream. The
resulting toluene slurry was evaporated in a combination vertical thin
film/horizontal
dryer to produce a dry solid. The hottest zone in the dryer was operated at a
temperature of 550 F. Analysis of the dry solid gave less than 0.5 weight%
toluene
extractable oil, which indicates over 99.9% oil removal. This material was
found to
sufficiently deoiled to allow recovery of the active metals using a water
based
leaching process. An analysis of the permeate oil stream showed no detectible
level
of molybdenum, which provides confirmation that the molybdenum based catalyst
was quantitatively recovered into the clean toluene slurry.
[0172] The single stage cross-flow filtration membrane module run eight
times in sequence simulated an eight stage cross-flow system. However, a very
large
amount (7.75 times the fresh slurry rate) of toluene was used since each stage
was
cross-flow and a very high deoiling extent was targeted. In an embodiment,
toluene is
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Date Recue/Date Received 2020-08-06
added only to the last stage and the toluene permeate cascades to the prior
stage,
requiring perhaps 5 or 6 stages (and a toluene rate of 2-3 times the fresh
slurry rate),
[0173] Dynamic Filtration Example. Catalyst in oil exchanged with toluene
was tested at 100 C (temperature correction base). Twenty gallons of a
catalyst/oil
slurry feed were tested. First, the solids were concentrated in oil and then
the solids
were washed or diafiltered in oil slurry using toluene as the wash solvent
(i.e., the oil
was exchanged with solvent). The pumpable catalyst/oil slurry contained 14
weight
% catalyst solids and other solids and 86 weight % oil. In an embodiment, the
oil is
removed and replaced by toluene until the oil concentration is less than about
2
weight %.
[0174] Specifically, toluene was used as a replacement solvent to displace the
oil and keep the total solids at a pumpable level. Any permeate containing oil
or
toluene can be sent to a distillation column for recovery. The final washed
catalyst
solids can be further treated using another technology. Only oil, toluene, and
soluble
solids would pass through the membrane, while catalyst solids would be
retained,
Accordingly, catalyst slurry in a liquid form with reduced amounts of oil is
produced,
which would be suitable for additional treatment steps. In an embodiment, at
least
about 95 weight % of the solids in the final washed concentrate (retentate) is
recovered. Heating equipment was used and a sealed nitrogen purged tank was
used
to process the feed liquid.
[0175] Testing was conducted by isolating as many of the variables as
possible to determine optimum variables. Variables included type of membrane,
temperature, pressure, concentration factor, and fouling. Variables were
tested as
follows.
[0176] The sample material was pre-screened using a 100-mesh screen to
remove large particles and then placed into a feed tank connected to a Series
L
V*SEP Machine from New Logic. The membranes were installed and feed was
introduced and pumped into the Series L V*SEP Machine.
[0177] Step 1, Membrane Study. The membrane study was used to evaluate
a variety of membranes on the sample material to determine the optimum
membrane
in terms of flux and/or permeate quality. The performance was measured in
"recirculation mode," meaning that the material was not concentrated but the
separated streams were returned to the feed tank and only the relative
performance of
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Date Recue/Date Received 2020-08-06
each membrane under the same conditions was measured. A exemplary
"recirculation
mode" is shown in Figure 11.
[0178] Step 2. Pressure Study. The pressure study was used to determine the
optimum pressure of the chosen membrane on the particular feed material. The
permeate rate was measured as incremental increases in pressure were made to
the
system. The pressure study determined whether it is possible to reach a point
at
which increased pressure does not yield significant increase in permeate flow
rate,
and at what pressure increasing pressure further does not yield significant
increase in
permeate flow rate.
[0179] Step 3, Long Term Line-Out Study The long term line-out study was
used to measure the flux versus time to determine if the permeate rate is
stable over a
period of a time. The long term line-out study was an extended test to verify
whether
the system will lose flux, as do tubular cross flow systems. The results of
the long
term line-out study can also be used to determine a cleaning frequency, if one
is
necessary.
[0180] Step 4. Washing Study The washing study was designed to measure
flux versus wash volume in order to evaluate an average flux over each
individual
washing. The washing study was completed in batch mode, as the membrane area
of
the Series L V*SEP Machine was only 0,5 ft2. Permeate was continually removed
from the system while the concentrated material was returned to the feed tank,
The
washes were added one at a time and when an equivalent amount of permeate
compared to the added wash water was removed then one wash was complete. For
the washing study, one continuous wash was completed in batch mode. As
permeate
was removed, additional toluene was added to the tank.
[0181] Step 5. Concentration Study The concentration study was designed to
concentrate the solids to a desired endpoint, if not obtained in the washing
study. The
concentration study was completed in batch mode, as the membrane area was only
0,5
ft2. Permeate was continually removed from the system while the concentrated
material was returned to the feed tank. The resulting data was used to
determine the
average flux over the concentration/recovery range, which, in turn, allows for
preliminary system sizing.
[0182] Test conditions included a temperature of about 90-100 C (temperature
corrected to 100 C), a pressure of about 100-120 psi for the membrane study
and 90
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Date Recue/Date Received 2020-08-06
psi for the washing study, a sample size of 20 gallons, and, as noted above, a
membrane area of 0,5 ft2.
[0183] Results - Membrane Selection. Two membranes having good
chemical resistance and that can tolerate high temperature, detailed in Table
1, were
selected for study.
Table 1, Membranes Tested
Membrane Type Pore Maximum Water
Size Temperature Flux*
Teflon on Halar Microfiltration 0.05 pm 200 C
500 gfd
Teflon on Woven Fiberglass Microfiltration 0.1 pm 200 C
750 gfd
*Average Batch Cell Test Results on New Membrane at 60 psi and 20 C
[0184] The relative performance of each of the selected membranes was
tested, The feed tank was prepared with the sample feed material and the
system was
configured in "recirculation mode". Each of the membranes shown above was
installed and a two to four hour "line-out study" was conducted. The membranes
were compared based on flux and permeate quality. Table 2 shows the relative
performance of each membrane.
Table 2. Results of Membrane Selection
Membrane Initial Flow* Ending Flow* Pressure
Teflon on Halar 42.6 ml/min 47.8 ml/min 100 psi
Teflon 7) on Woven Fiberglass 25.8 ml/min 11.7 ml/min 120 psi
*Temperature corrected to 100 C
[0185] Figure 12 is a graph illustrating the results of the membrane study.
The operating temperature was 100 C. Factors used to select a membrane may
include, for example, flow rate, permeate flux rate, filtrate quality,
chemical
compatibility of the membrane, mechanical strength of the membrane, and
temperature tolerance of the membrane. The 0.05 p.m Teflon membrane had
better
flux rates than the 0.1 m Teflon membrane. Analytical testing results on the
filtrate from each showed that the 0.05 p,m Teflon membrane had 181 ppm of
suspended solids in the filtrate, while the 0.1 p,m Teflon membrane had only
72 ppm
of total suspended solids. The feed slurry was 9.18 weight % solids and 90,82
weight
% oil. Accordingly, the 0.05 1.1111 Teflon membrane provided a better flow
rate but
worse permeate quality.
[0186] In addition to an excellent flow rate or permeate quality, the membrane
must be durable and able to stand up to the feed material. Many materials are
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Date Recue/Date Received 2020-08-06
available for membrane construction, which remains an available optimizing
technique. In addition to the membrane itself, all of the other wetted parts
should be
examined for compatibility, Both Halar (ethylene chlorotrifluoro-ethylene)
and
woven fiberglass material chemically inert and would be compatible with
toluene and
the oil carrier. In addition, both would be capable of tolerating the 100 C
process
temperature. The membranes are essentially equivalent in terms of chemical
compatibility and temperature tolerance criteria.
[0187] However, in terms of mechanical strength of the membranes, woven
fiberglass backing material is much stronger and would hold up better over the
long
term than Halar . Accordingly, the 0.1 um Teflon membrane on woven fiberglass
was chosen for further analysis.
[0188] Pressure Selection. The results of the pressure study are shown in
Figure 13. The operating temperature was 100 C. An optimum pressure was
determined by measuring the flux at various pressures. The greatest flux
occurred at
90 psi, giving an optimum pressure of 90 psi,
[0189] Initial Concentration. The system was started up first in
"recirculation
mode" and set to the optimum pressure and expected process temperature. The
system was run for a few hours to verify that the flux was stable and the
system has
reached equilibrium.
[0190] The permeate line was then diverted to a separate container so the
system was operating in "batch" mode. The permeate flow rate was measured at
timed intervals to determine flow rate produced by the system at various
levels of
concentration, As permeate was removed from the system, the solids
concentration
rose in the feed tank. Figure 14 illustrates a batch mode operation.
[0191] Initial concentration allows for reduction of the volume of the feed by
removing oil and concentrating the solids. As a result, it is possible to use
less
volume of wash solvent. No wash solvent has been added and only the initial
solids
are concentrated.
[0192] Table 3 shows the mass balance results of the initial concentration.
Table 3, Mass Balance Results
Initial Volume Ending Volume % Recovery Initial %
Solids Ending % Solids
20 gallons 11,7 gallons 41.49% 9.18% 15.69%
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Date Recue/Date Received 2020-08-06
[0193] The initial concentration was done at about 100 C and a pressure of
about 90 psi. While further concentration could have been performed, after the
initial
concentration the feed was very viscous and the flux rates were relatively low
due to
the viscosity. It was believed that the addition of toluene would cut the
viscosity and
greatly improve the flux rate. Concentrating was stopped at about 41%
recovery,
since a significant volume reduction had taken place, the percentage of solids
had
risen to a respectable level, and flow rates could be improved with toluene
addition,
[0194] Table 4 shows system performance during the initial concentration.
Table 4. Initial Concentration Results
Initial Flux Ending Flux Average Flux Pressure Temperature
34,5 gfd 28.2 gfd 29.6 gfd 90 psi 100 C
[0195] Diafiltration Process. Once the feed had been volume reduced by 41%
and about 11,7 gallons of feed remained, the system configuration was
preserved with
permeate being diverted to a separate container and the reject line being
returned to
the feed tank. Also, clean toluene was added to the feed tank in a topped off
fashion
to maintain the tank level and replenish the feed volume as filtrate was
removed.
[0196] Processing continued for several days, During the washing study, nine
small samples were taken of the permeate and concentrate at different times
throughout the washing study. After about 75 gallons of was solvent had been
added,
the washing process was stopped. Initially, the filtrate was very dark and
oily. As the
wash process continued, the filtrate became lighter in color until the color
was a very
light amber. Table 5 shows the mass balance results during the diafiltration.
Table 5. Diafiltration Mass Balance Results
Filtrate Wash - Permeate
Reject
ID Time Removed Volume Solids Solids
1 165 min 1.8 gal 0.1x 1 ppm 917%
2 301 min 3.1 ,gal 0.3x - 31)Prn 9.88%
3 906 min 10.3 gal 1.0x 153 ppm 4.62%
3a 1117 min 12.5 gal _ 1.3x _ .. 4 ppm .. 11.31%
4 2362 mln 38.3 gal 4.0x 1500 ppm 7.86%
5 2974 min 58.0 gal 5.7x _ 406 ppm 24.51%
6 3122 min 61.1 gal 5.9x 481 ppm _ 41.33%
7 3180 min 61.9 gal 6.0x 137 ppm 38.58%
8 3430 min 71.9 g_al 6.9x 21 ppm 25.01%
9 3983 min 80.3 gal 7.6x 32 ppm 42.41%
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[0197] Prior to testing, it was estimated that six wash volumes would be
enough to theoretically "clean" the solids and remove enough oil. During the
course
of testing, about 75 gallons of clean toluene were used. Diafiltration was
stopped
after the supply of toluene was exhausted and after more than six wash volumes
had
been completed. The ending volume was concentrated until the feed slurry was
reasonably thick. Concentration was stopped when the slurry was quite thick
and
there existed a risk of plugging.
[0198] Figure 15 is a graph of the diafiltration study. Process conditions
included a temperature of 100 C, a pressure of 90 psi, and the Teflon on
woven
fiberglass membrane with 0.1 p.m pore size. The average flux plot includes
data from
the initial concentration, not shown in the graph. The actual average flux
during
testing was 112 gfd.
[0199] During testing several observations were made: 1) non-woven
fiberglass drain cloth ("Manniglass") did not hold up mechanically; 2) nylon
"Tricot"
drain cloth did hold up well; 3) polypropylene drain cloth worked acceptably
but
swelled; 4) when the system sat idle, solids would settle in the piping and
plug the
system; 5) good pre-screening is needed to catch agglomerations; 6) no
significant
H2S was present in the sample (300 ppm was present initially but removed); 7)
flux
rates were low on oil, but improved greatly once toluene was added; 8) Viton
elastomers swelled badly and failed several times; 9) low cross-flow allowed
accumulation of solids in the filter head; and 10) a cake layer built up on
the
membrane surface.
[0200] As mentioned above, at first, the filtrate was dark colored, although
not
turbid. Toward the end of the diafiltration, the color changed to a light
amber color.
During testing, there were several instances where the filter head was
disassembled to
replace leaking Viton seals and failed drain cloth materials, Each time the
filter
head was opened, the permeate chamber was contaminated with the feed slurry.
Upon resumption of operation, the filtrate would exhibit some turbidity
initially, and
then would clear up as the contamination cleared. Large variations were
observed in
the percentage of solids in the filtrate. Without wishing to be bound by
theory, it is
believed that the large variations were observed in the percentage of solids
in the
filtrate can be explained by permeate chamber contamination.
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Date Recue/Date Received 2020-08-06
[0201] Table 6 shows the permeate quality after a membrane change.
Table 6. Diafiltration Time Results
ID Total Time Delta Time Permeate Solids
2313 min 0 min Membrane Change
4 2362 min 49 min 1500 ppm
2792 min 0 min Membrane Change
2974 min 182 min 40E3 ppm
6 3122 min 330 min 481 ppm
7 3180 min 388 min 137 ppm
8 3430 min 638 min 21 ppm
9 3983 min 1191 min 32 ppm
5 [0202) The membrane itself should be able to hold back a significant
percentage of solids. Solids in the permeate may not be a result of solids
passing
through membrane pores. Rather, contamination might have contributed to solids
in
the filtrate. In addition, swelled Viton o-rings might have been providing,
at best, a
marginal seal. Each time the membrane was changed a new set of o-rings was
installed. With no contamination of the permeate chamber and with good o-ring
seals, the solids in the filtrate might be in the range of about 10-20 ppm,
[0203] Another possible explanation for the solids in the filtrate is the
distribution of pore sizes in the membrane. In particular, while membranes
have
nominal pore size ratings, the actual pore sizes in any given membrane vary.
The
pore size distribution curve is shaped like a bell curve. The nominal pore
size rating
is normally the mean of all the sizes. Thus, a membrane with a nominal pore
size
rating of 0.1 p.m can have pores as large as 1.0 p.tm. Examining the particle
size
distribution of the catalyst solids, there could be some overlap, as shown in
Figure 16.
[0204] Teflon membranes rated at 0.05 p.m, or smaller, might even be too
large to completely remove all solids. While smaller membranes, with pore
sizes
down to 0.01 i.tm, made of other materials including polyvinylidene difluoride
(PVDF; Kynart), might have better solids removal capability, such membranes
might
have lower chemical and temperature tolerance and be less durable over time.
[0205] System with Integrated Cross-flow Filtration & Combi Drying Units:
A slurry feed stream (100 lbs/hr) from a heavy oil upgrading unit is provided.
The
stream contains 20 lbs. of spent catalyst in 80 lbs. of heavy oil with the
heavy oil
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Date Recue/Date Received 2020-08-06
being unconverted heavy oil / heavier hydrocracked products. About 300 lbs, of
solvent is also provided to the cross-flow filtration unit. The cross-flow
filtration unit
has a plurality of filter stages with operating conditions as shown in Table
7:
'Filter stage -Temperature (F) .. Pressure (psig)
1 200 30
2 200 50
3 200 70
4 200 90
200 110
5 [0206] The retentate stream (100 lbs) from the cross-flow filtration
unit
comprises 20 wt. % spent catalyst, 79,9 wt. % of a solvent such as toluene,
and 0.1 wt,
% heavy oil is sent to a drying zone connected in series, The filtrate stream
contains
approximately 220,1 lbs. solvent and 79,9 lbs. heavy oil is sent to a solvent
recovery
unit.
[0207] The drying apparatus used in the 1 St stage of the drying zone is an
LCI
Combi Dryer heated indirectly by either steam or hot oil, with an operation
temperature of 232 F in the vertical section, the first half of the horizontal
section
operating at approximately 800 F and the last half of the horizontal section
(or the
cooling section) is between 70 to 77 F, The Combi dryer is maintained at a
pressure
ranging from 0 to 10 psig, with a counter-current nitrogen flow maintained in
the
range of 0.5 to 1 scf/min. Dry powder catalyst exiting the Combi dryer at a
temperature ranging from 100 to 110 F and with a retention time in the
equipment of
10 to 120 minutes. TGA (thermogravimetic analysis) is used to measure the oil
content in the dry catalyst powder, showing a heavy oil concentration of less
than 0.5
wt, %.
[0208] System with Cross-flow Filtration & Two-Staged Drying Units: The
previous example is repeated with the addition of a rotary kiln dryer in
series with the
Combi dryer. The dry powder from the Combi unit is sent to a rotary kiln dryer
at a
rate ranging from 4 to 6 lbs. per hour. The kiln operates temperature of about
800 F,
having a kiln rotation from 1 to 5 rpm, and a retention time ranging from 30
to 60
minutes. Nitrogen flow is co-current in the rotary kiln. TGA analysis shows a
oil
concentration in the powder exiting the kiln of less than 0.1 wt%, and at an
amount of
less than 0.05 wt%. in one embodiment.
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Date Recue/Date Received 2020-08-06
[0209] For the purposes of this specification and appended claims, unless
otherwise indicated, all numbers expressing quantities, percentages or
proportions,
and other numerical values used in the specification and claims, are to be
understood
as being modified in all instances by the term "about." Accordingly, unless
indicated
to the contrary, the numerical parameters set forth in the following
specification and
attached claims are approximations that can vary depending upon the desired
properties sought to be obtained by the present invention. It is noted that,
as used in
this specification and the appended claims, the singular forms "a," "an," and
"the,"
include plural references unless expressly and unequivocally limited to one
referent.
As used herein, the term "include" and its grammatical variants are intended
to be
non-limiting, such that recitation of items in a list is not to the exclusion
of other like
items that can be substituted or added to the listed items.
[0210] This written description uses examples to disclose the invention,
including the best mode, and also to enable any person skilled in the art to
make and
use the invention. The patentable scope is defined by the claims, and can
include
other examples that occur to those skilled in the art. Such other examples are
intended to be within the scope of the claims if they have structural elements
that do
not differ from the literal language of the claims, or if they include
equivalent
structural elements with insubstantial differences from the literal languages
of the
claims.
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