Note: Descriptions are shown in the official language in which they were submitted.
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Advanced Method and Apparatus to Process Bitumen
Containing Impurities
INTRODUCTION
This invention relates to the mining industry which deals with extracting
and processing bitumen from various sources, and by way of example such
extracting and processing is herein focused with the recovery of oil from oil
sands, which is also known as "tar sands," whose bitumen contains sand, clay
and moisture, and is mined in open-pit practice.
BACKGROUND
In open-pit mining, large, hydraulic/electric shovels do the digging and the
loading of trucks that deliver the mined oil sands to processing complexes.
These complexes use very large quantities of water to wash the sand from the
bitumen. After the separation of the sand from the bitumen, the water is too
dirty
to discharge into a body of water, such as a river, from where the water was
derived. Current practice is to store such dirty/oily water in ponds, which
are
called tailings ponds, that can be as big as the mines themselves, creating a
major negative environmental problem. Further, the processing complexes
utilize
large quantities of natural gas to heat the water to about 170 F to wash out
the
bitumen as a first step and is followed by a second step to heat the water
into
steam to about 900 F and compress the raw bitumen to some 1,500 PSI to
upgrade the oil in the bitumen by subtracting carbon to result in a lighter
hydrocarbon liquid.
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OBJECTIVE
The main object of the present invention is to produce valuable,
desulfurized light liquids directly from open-pit mining of crushed run-of-
mine
bitumen.
Another object of this invention is to do away with the use of water in the
processing of the oil sands which contain the bitumen.
Therefore another object of the present invention is to provide a superior
technology and apparatus that will lower the processing cost of oil sand
bitumen.
Yet another object of the instant invention is to eliminate the use of
tailings
ponds which contain clay and sand particles that take several years to settle,
and
when they do settle, produce bodies of water containing toxic chemicals such
as
naphthenic acid and polycyclic hydrocarbons.
Further another object of the present invention is to reduce the energy
consumption in the processing of bitumen from the oil sands.
Still another object of the instant invention is to produce a clean, hydrogen
rich synthetic gas as a by-product that can be converted to a clean transport
fuel
such as gasoline, or dimethyl ether which can replace dirty diesel to fuel the
large
trucks that transport the oil sands from where it is mined to the processing
complexes.
Further still another object of the present invention is to provide an
environmentally closed method and equipment to carry the method.
Further yet another object of the instant invention is to provide a
continuous method and equipment to carry the method.
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It is therefore another object of the present invention to co-produce electric
power as a by-product that is useful in the recovery and processing of the
bitumen.
It is yet another object of the instant invention to co-produce a fertilizer
as
a by-product which is useful in the acceleration of mined land reclamation.
It is still another object of the present invention to co-produce a fuel in
the
form of a char from the mined bitumen which is utilized as the energy source
in
the pyrolysis step which de-asphalts the bitumen.
Other objects of this invention will appear from the following detailed
description and appended claims. Reference is made to the accompanying
drawings forming a part of this specification wherein like reference
characters
designate corresponding parts in the various figures.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a general layout of the present invention.
Figure 2 illustrates a pyrolyzing reactor in perspective which can efficiently
process the bitumen from open-pit mining.
Figure 3 is a partial, longitudinal section of the pyrolyzing reactor,
including a cross-section view taken at A-A of Figure 3.
Figure 4 illustrates the end view of a battery of pyrolyzing reactors to
satisfy large production needs.
DETAILED DESCRIPTION OF THE DRAWINGS
Reference is made to Figure 1 wherein the following numerals represent
the main components: 10 marks the pyrolyzer; 11 marks the char gasifier; 12
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marks the char quencher; 13, the hot gas cleanup; 14, the separator of the
syngas from the light liquids; 15, the combined cycle electric power
generation;
16, the alternating reducing reactors comprising a portion of the fertilizer
plant;
17, the fertilizer (oxamide) reactor; 18, the dual beds of activated carbon
for
mercury removal; and 19 is the equipment to feed the raw materials to be
processed in pyrolyzer 10.
Pyrolyzer 10 is made up of charger 20, pyrolyzing chamber 21, radiant
zone 22, downcomer 23, and flow control valve 24, from which bifurcated pipe
25
forms a delivery pipe assembly, with pipe 26 connecting downcomer 23 thence to
char gasifier 11 by way of control valve 28, and pipe 27 connecting downcomer
23 to char quencher 12 by way of control valve 29.
Gasifier 11 comprises vessel 30, which is equipped with injection points at
different levels for a gas containing oxygen, such as air, to react with hot
char to
produce a fuel gas; gasifier 11 possesses at its bottom discharge cooler 31,
with
exit port 32. Below cooler 31, lockhopper 33 is provided, which is controlled
by
upper valve 34 and by lower valve 35. At about mid-point of gasifier 11, a
special
manifold marked by numeral 36 serves for the injection of flue gases
containing
CO2 for reducing the CO2 into 2CO. Quencher 12 comprises vessel 37, which is
equipped with multi-level manifolds, like manifold 38, that gradually cool the
char
below ignition point prior to being periodically discharged to the atmosphere
by
means of valve 39.
The equipment to feed the mined raw materials is marked by numeral 19,
and comprises skip 40, which elevates the raw bitumen that contains sand, clay
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and moisture from ground to conveyor 42 and skip 41, which elevates the char
(fuel) from ground to conveyor 43, which in turn conveyor 42 discharges to
feeder 44 and conveyor 43 discharges to feeder 45.
Gas cleanup 13 is made up of three vessels, marked by numerals 46, 47,
and 48. Vessel 46 cracks and simultaneously desulfurizes the volatile matter
from pyrolyzer 10; vessel 47 cleans the fuel gas made up of nitrogen (N2) and
carbon monoxide (CO) gas from gasifier 11; and vessel 48 serves to regenerate
the sorbent and produce elemental sulfur directly. All three vessels are
equipped
with feeders denoted by numeral 49. Vessel 48 interconnects with vessels 46
and 47 via the inverted Y-pipe that is marked by numeral 50, which is equipped
with diversion valves 51. Gas cleanup 13 is equipped with pneumatic
transporters 52 to convey the spent sorbent from vessels 46 and 47 to
regenerator 48.
Cyanogen make-up equipment 16 comprises reactor 53 "A" and reactor
53 "B" with gas temperature moderator denoted by numeral 54 being upstream
of "A" and "B," and chiller-liquefier which is denoted by numeral 55 being
downstream. A separator marked by numeral 56 is provided to segregate the
liquefied cyanogen from the unreacted gases which are directed (not shown) to
pyrolyzer 10.
Downstream of separator 56, oxamide maker 17 is located. It consists of
reactor 57, settling tank 58, filter press 59, drier 60, and stacker 61. Pump
62 is
provided to separator 56 to pump the liquefied cyanogen to evaporator 63, and
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pump 64 serves to circulate the liquid catalyst to the top of reactor 57; a
heater
denoted by numeral 65 serves to adjust the temperature of the liquid catalyst.
The mercury removal system marked by numeral 18, which consists of
activated carbon beds, comprises beds "a" and "b," with the practice being
when
bed "a" is in absorption of mercury, bed "b" is in regeneration mode, and when
bed "b" is in absorption, while bed "a" is in regeneration mode.
The electric power generation system in this invention, marked by numeral
15, is preferably fueled with a clean, lean gas (fuel gas) fed from cleanup
vessel
47 and comprises gas turbine numeral 66, heat recovery steam generator 67,
and steam turbine 68, forming a combined cycle configuration which is a most
efficient way of generating power.
Figure 2 illustrates in perspective the pyrolyzer denoted by numeral 10
and is made up of feeders 44 and 45, charger 20, pyrolyzation chamber denoted
by numeral 21, radiant zone 22, and control valve 24. The oil sands and the
char are fed by way of pipes 81 and 85, respectively, using a "Y" piping
configuration. The exit port for the H2 rich volatile matter is marked by
numeral
86.
Referring now to Figure 3, lance 71, in addition to its capability to inject
oxygen through its tip denoted by numeral 82, is equipped with injection
nozzles
on its side denoted by numeral 83. Lance 71, like mandrel 70 and ram 69, is
adapted to advance and retract independently, and because of the high
temperature surrounding lance 71, it is cooled preferably with water
circulating
through it in a closed loop.
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It is to be noted that in providing lance 71 wherein the char charged is
combusted under suppressed conditions (in a pressurized, controlled reducing
atmosphere), heat transfer within chamber 21 is markedly improved, thus
enhancing the rate at which the bitumen, containing sand, clay and water,
devolatilizes into volatile matter, while vigorously cracking tars to such an
extent
that carbon is deposited on the sand and clay while the water turns into water-
gas (H2+CO) within chamber 21. Further, the bitumen is heated peripherally by
means of injection nozzles disposed through shell 77 and refractory 75, one of
which being marked by numeral 80, with such nozzles being supplied with a gas
containing oxygen furnished by manifold 79, thus providing direct,
pressurized,
bi-directional, efficient heating that increases the release of the volatile
matter
from the bitumen to such an extent that virtually all the oils in the bitumen
are
recovered in vapor form while its tar is carbonized, producing carbonized sand
and clay.
In the instant application, wherein carbon in the char (as a core within
chamber 21) is combusted in a pressurized reducing atmosphere, the
combustion of bitumen which surrounds the core is virtually prevented. To
achieve this objective, numeral 21 is the pyrolyzing chamber, numeral 20 is
the
charger, numeral 81 is the feed hopper, numeral 69 is the ram, numeral 70 is
the
mandrel, numeral 71 is the injection lance, numeral 82 is the nozzle at the
tip of
lance 71, and numeral 83 is one of the several nozzles disposed at the side of
lance 71, numeral 72 is the char fuel, numeral 73 is the charged bitumen
containing sand, clay and water, and numeral 75 is the refractory/insulation
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which is configured as a monolithic structure that is reinforced with metallic
needles such as stainless steel needles, marked by numeral 84 (shown in
SECTION A-A), somewhat similar to imbedding steel wire in reinforced concrete;
this structure is cast in place against shell 77.
In the case of heating the material peripherally directly by combusting char
(not shown), oxygen is introduced through shell 77 by means of injectors, one
such injector being marked by numeral 80 supplied by manifold 79. When
combustion takes place peripherally and the material is bitumen, it is
possible to
also charge char around the perimeter of the bitumen annulus by providing an
additional mandrel that circumscribes ram 69 to form a ring of char around the
periphery of the bitumen. In so doing, the combustion effected by injectors,
such
as injector 80, consumes the ring of char, instead of combusting the bitumen.
In the case of heating the material peripherally indirectly, numeral 74
represents the manifold for distributing hot heating gas into a plurality of
small-
diameter flues installed in refractory/insulation 75, one such flue being
marked by
numeral 76 carrying hot gases that heat refractory 75, which in turn heats
indirectly the bitumen marked my numeral 78 shown in Section A-A. It is to be
noted that towards the exit end of pyrolyzing chamber 21, the bitumen has been
completely devolatilized, yielding a residual consisting of a char made up of
carbonized sand and clay devoid of any oil. Referring to Figure 4, it
illustrates a
group of pyrolyzers configured in battery form to provide a modular structure
in
order to enable it to efficiently scale-up productive capacity by replication.
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OPERATION
To describe the operation of this invention based on extensive test work
that had taken place and referenced hereinafter begins with using unprepared,
crushed run-of-mine bitumen preferably of three inches and under that is
directly
fed into a battery of pyrolyzers where the cracking of asphalt results in a
tar-free
bitumen in the form of volatile matter containing a hydrogen rich, non-
condensable raw syngas together with vaporized light liquids and incandescent
char. The syngas and vaporized light liquids are desulfurized and upgraded in
a
first hot gas cleanup, while a part of the hot char is gasified with air into
a fuel gas
and oil-free, tar-free tailings containing clean sand and clean clay; the
other part
of the char is used as fuel for heating the pyrolyzer. The fuel gas from the
gasifier is passed through a second hot gas cleanup, producing a clean,
desulfurized lean gas which is ideal to generate clean, efficient electric
power
with the emitted CO2 from power generation collected and converted to slow-
release fertilizer that can be mixed with top soil, which had been removed
prior to
mining the bitumen, to form a rich top soil. The oil-free, tar-free tailings,
consisting of clean sand and clean clay, are used in the reclamation of the
open-
pit mine and topped with the rich soil to enhance and accelerate plant growth
to
create forest land.
The test work performed in the Applicant's pilot in cooperation with Sun
refining proved that the method described herein, which uses CaO as sorbent,
produced light liquids from cracking residuum (heavy bitumen) from its
Philadelphia Refinery against CaO as sorbent. Such light liquids were referred
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to by Sun as "excellent feedstocks and can be separated by a simple
distillation
process into valuable intermediates"; see Exhibit 1, page 1 of 2.
Data that was produced by way of the tests (see Exhibit 1, page 2 of 2)
showed that the Ramsbottom Carbon (by weight percentage) of the residuum
was converted from 18.2% to 1.24% in test Run #3, to 0.59% in test Run #4, and
to 0.31% in test Run #5. Further, for the Pour Point temperature in F, the
residuum was 145 F, and in tests #3, #4, and #5, the temperature was reduced
to -20 F. Also, the INITIAL BOILING POINT of the residuum dropped from
802 F: in test # 3 to 108 F, in test # 4 to 154 F, and in test #5 to 135 F.
This
data show that the method herein described-which is based on the replication
of the test work performed, except at commercial scale-should produce
outstanding results in producing light liquids from bitumen. It is also
important to
disclose herein that the syngas (Rich Gas Sample -Test Run #3) produced in
Mole % as follows: H2 - 57.3%; CH4 - 36.6%; N2 - 3%; C2H4 - 1.8%; CO -
1.6%; and CO2 - only 0.7%.
With respect to residual bitumen after pyrolysis, tests were conducted in
1997 at Applicant's Process Development Unit (Exhibit 2) making metallurgical
coke from coal; the coke produced was tested for various properties including
residual volatile matter after pyrolysis. In testing the coke made from
Bethlehem
Steel's coal, the residual volatile matter was 0.58%, and with coke made from
U.S. Steel's three coals, the residual volatile matter was 0.55% from Blue Tag
Coal, 0.48% from Low-Vol coal, and 0.70% from White Tag coal; see Exhibit 3.
In the tests conducted, whether the feedstock was heavy oil (bitumen) or coal,
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these feedstocks were pyrolyzed in sealed tubes in which cracking of tars took
place as proposed herein; in the case of sulfur removal, the gas produced had
no
H2S, as reported in Exhibit 1, page 1 of 2. Production of elemental sulfur
during
regeneration was reported by Sun; see Exhibit 4, and the chemistry for such
results are published in The Making, Shaping and Treating of Steel, 11th
edition;
see Exhibit 5.
In conclusion, based on the test work done and the herein description, the
objectives listed towards the beginning of this disclosure are achievable. It
is
submitted herein that the instant method and apparatus provide major
improvements over the conventional practice of processing open-pit mining of
bitumen including oil sands. The details of construction mentioned above are
for
the purpose of description and not limitation, since other configurations are
possible without departing from the spirit of the invention. Further, other
materials besides bitumen from oil sands can be processed in the apparatus
herein described.
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