Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02168392 1996-05-02
SETTLING AIDS FOR SOLIDS IN HYDROCARBONS
FIELD OF THE INVENTION
The present invention relates to methods for accelerating settling
of solids in hydrocarbon fluids. The methods of the present invention are
particularly efficacious at accelerating the settling of FCC catalyst fines in
an oil slurry.
BACKGROUND OF THE INVENTION
Unrefined hydrocarbons such as crude oil, resids and bottom streams
often contain finely divided solid matter which often must be removed prior
to further use or processing. These solids can include solids of a soil-like
nature, finely divided silicas, clays, silt and coke, and metal oxide and sul-
fide corrosion solids. These solids may include traces of metal particles
such as lead, nickel, chromium and the like, and salts thereof.
For instance, fluid catalytic cracker (FCC units use a fluidized bed
of zeolite type aluminosilicate clay particles to crack heavy petroleum
fractions into lighter fractions at elevated temperatures. The catalyst is
eventually deactivated by poisoning or coking. These spent fines must
be removed from the FC;C on a continual basis so that fresh catalyst can
be added.
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Some of this slurry oil containing the spent fines is then typically
settled in tankage, though hydrocyclones are sometimes used to accel-
erate the separation process. Both native and synthetic components of
the slurry oil have a dispersant effect which retards the settling of the
fines.
The present inventor has discovered that certain chemical agents,
when added to the slurry oil, have an anti-dispersant or coagulant effect
which accelerates the settling process. This produces a cleaner decant
oil (typically <0.05 wt % ash) in a shorter period of time and can then be
sold as carbon black feedstock or residual fuel oil.
DESCRIPTION OF THE RELATED ART
U.S. Pat. No. 4,539,099 describes a method to enhance the grav-
ity settling rate of suspended solids from hydrocarbon oil by the addition
of an oxyalkylated phenol formaldehyde resin glycol ester. U.S. Pat. No.
5,476,988 describes the use of quaternary ammonium compounds and
U.S. Pat. No. 5,481,059 describes the use of polyacrylic acid crosslinked
alkylphenol-formaldehyde alkoxylates for this application.
Various water washing methods have been described. U.S. Pat. No.
4,407,707 discloses a method of removing particulate solids from hydrocar-
bon oil by adding to the oil an alkoxylated sorbitan fatty ester (optionally
with an organo sulfonic acid or salt and/or a demulsifier), then washing the
solids out of the oil with 5-50% water. U.S, Pat. No. 2,952,620 describes a
process for removing solids from hydrocarbon oil by washing the oil with
water containing a nonionic surfactant. Any nonionic surfactant which
works with this water washing method is said to work. There is no hint
CA 02168392 1996-05-02
or suggestion of such surfactants, which would implicitly include those of
U.S. Pat. Nos. 4,407,707 and 4,589,099, having an effect in the absence of
water washing. U.S. Pat. No. 4,889,618 discloses a process for removing
solids from hydrocarbon oil by washing the oil with water containing
concentrated caustic.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to methods for accelerating the
settling of finely divided, oil-and-water-insoluble solids in hydrocarbon
fluids comprising adding to the hydrocarbon fluid an alkylphenol-formal-
dehyde resin alkoxylate. More particularly, the present invention relates
to methods for accelerating the settling of spent fluid catalytic cracker
(FCC) catalyst fines in an oil slurry comprising adding to the oil slurry an
alkylphenol-formaldehyde resin alkoxylate.
The alkylphenol-formaldehyde resin alkoxylates generally have
molecular weights in the range from about 500 to about 5,000 with a
range of about 1,000 to about 2,500 preferred. The alkyl group may be
linear or branched and have 1 to about 24 carbon atoms with a range of
about 4 to about 9 preferred. The alkoxy group has about 2 to about 4
carbon atoms with 2 preferred. The alkoxyiation comprises 20 to 80% by
weight of the molecule with about 50% preferred,
The alkylphenol-formaldehyde resin alkoxylates, which for pur-
poses of the present invention include mixtures of these compounds,
prove effective in a variety of hydrocarbon fluids. These hydrocarbon
fluids are generally unrefined hydrocarbons that are prone to containing
CA 02168392 1996-05-02
finely divided, oil-and-water-insoluble solids. For purposes of the present
invention, hydrocarbon fluids include but are not limited to crude oils and
fractions or residuals of crude ails boiling aver about 400°F.
Actual dosage ranges far the alkylphenol-formaldehyde resin alk-
oxylates depend upon the characteristics of the hydrocarbon to be treat-
ed. These characteristics can vary and include the type of hydrocarbon,
the type and amount of finely divided solids present, the ail and water
solubility of the finely divided solids, and the presence of other impurities
and surfactants in the hydrocarbon fluid. For the purposes of this inven-
tion, the term "effective amount" is the amount of alkylphenol-formalde-
hyde resin alkoxylates necessary to accomplish the purpose of the treat-
ment. The effective amount will range from about 1 part to about 1000
parts of alkylphenol-formaldehyde resin alkoxylates per million parts of
hydrocarbon with a range of from about 10 to about 100 parts per million
parts of hydrocarbon preferred
The alkylphenol-formaldehyde resin alkaxylate can be fed to the
hydrocarbon to be treated neat or in a suitable solvent that is compatible
with the alkoxylate and the hydrocarbon. Examples of such solvents in-
clude but are not limited to petroleum distillates, aromatic naphthas,
mineral oils, alkyl ethers, esters and alcahols.
The following examples are intended to show the efficacy of the
present invention as an accelerator for settling finely divided, ail-and-
water-insoluble solids ire hydrocarbons and should not be construed as
limiting the scope of the invention.
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EXAMPLES
Catalyst Settling Aid Test.
5 This test measures the fraction of FCC catalyst fines which settle
to the bottom of a slurry sample compared to the amount which remains
dispersed on top. This test simulates slurry settling in tankage between
ambient temperature and 200°F.
Experimental
Collect 100 mL of FCCU slurry in 6 oz. bottles. Place bottles in a
water bath and heat to process temperature. Remove each bottle from
the bath and add the appropriate treatment to the desired bottles. Place
the bottles in an insulated shaker and shake on high speed setting for 10
minutes. Return the bottles to the bath and allow to stand undisturbed for
the predetermined settling period. This predetermined settling time for a
blank is determined by analyzing several untreated bottles according to
this test procedure at various time intervals centered on the tank's resi-
dence time (e.g., 5 hours, 1 day, 3 days, 7 days).
Test methods vary in the point at which the sample is split between
the top and the bottom portions for analysis at the end of the settling pe-
riod. The size of the top portion is used to designate the method used
(e.g., the "95% method" means the top 95% of the sample was sepa-
rated).
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For most samples, the "50% method" described below is used.
For extremely fast settling samples, a short settling time and the "95%
method" described below is used. For very slow settling samples, a long
settling time and the 20% or 10% variation of the 50% method is used.
50% method (or 20'% or 10%)
Pipet off the top 50 mLs (or 20°!° or 10°~) with a
syringe being
careful not to disturb the sample or insert the needle below the 50
(or 80 or 90) ml line, and transfer to a clean bottle. This is the
"top" sample. The original bottle contains the "bottom" sample.
95% method
Pour off ~95 mLs (i.e., what wilt easily pour) into a clean bottle.
This is the "top" sample. The remaining ~5 mLs in the original
bottle is the "bottom" sample.
Place filter pads in small petri dishes, dry uncovered at 220°F
for
one hour, remove from overt and allow to coal in a desiccator.
Shake the oil sample vigorously and carefully pour it, up to 50 mL at
a time, into a graduated 100 mL centrifuge tube, then double the volume,
up to 100 mL, with xylene or toluene. Heat the centrifuge tube to 180°F
in
a water bath. Centrifuge for 15 minutes.
Weigh and record filter weight. Place filter in a paraboloid filtration
funnel and wet with xylene or toluene to ensure a good seat for vacuum fil-
tration. Turn on the vacuum pump and pour a small amount of hot oil from
the centrifuge tube into the filter funnel and allow it to filter. Rinse with
xy-
lene or toluene. Continue adding small amounts and rinsing until all the
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sample has been filtered. Then rinse centrifuge tube and funnel with more
xylene or toluene until they are clean. Remove filter bowl and wash, under
vacuum, the filter pad with xylene or toluene followed by petroleum ether
or heptane.
Dry filter pad in an oven at 220°F for one hour. Allow to cool in
a
desiccator and reweigh.
Place the filters in glass petri dishes and ash in a muffle furnace at
900°F. Weigh again to determine catalyst weights, being careful not to
disturb loose ash on filters.
The % settled is calculated by the following methods:
20% method : % settled = bottom - 4 x too (g)
bottom + top (g)
50% method : % settled = bottom - top (a)
bottom + top (g)
95°~ method : % settled = bottom - toal19 la)
bottom + top (g)
A settling period which yields about 40 to 50°~ settled should be
chosen. Repeat the optimal procedure, determined from the blanks, after
adding chemical treatments at the process dosage.
Table I lists the various compounds tested and their individual
chemical formulas.
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TABLEI
Chemical legend
Treatment Description
A NR5-E05 (ac)
B NR5-E0~ (bc)
C NR5-E05 (bc) + NR4-PO~-E04 (bc)
D BR8-E03 {ac)
E AR4-EOa {ac) + NRg-PO~-E04 (bc)
F' NR3-EOg (ac) + AR4-E04 (ac)
G NR$-E05 (bc) + AR4-E04 (ac)
N = nonylphenolic resin
B = butylphenolic resin
A = amylphenolic resin
Rx = x moles of phenol per resin, on average
EOx = x moles of ethylene oxide per phenol, on average
POx = x moles of propylene oxide per phenol, on average
(ac) = acid catalyzed resin
{bc) = base catalyzed resin
The results of this testing are presented in Tables II to VII.
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Southern Refinery
Settled 14 days at 170°F
50°~ method
75 ppm active treatment
TA_ B,L.E II,
Treatment °h Settled
A -1
B 15
C 4
D 7
E 54
F 50
G 47
Blank 21
20
As demonstrated ire Table Il, a combination of amylphenol-formal-
dehyde ethoxylate resin and nonylphenol-formaldehyde ethylene oxide/
propylene oxide resin proved most effective at settling oil-and-water-
insoluble solids.
TABLE III
Mideastern Refinery
Settled 6 days at 170F
50% method
75 ppm active treatment
% Settled
Treatment Fluid #1 Fluid #2
A -19* 72
B 65* 70
C 78
D 75
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TAHLE III ~cont'd)
Mideastern Refinery
Settled 6 days at 170°F
50% method
5 75 ppm active treatment
Settled
Treatment Fluid #1 Fluid #2
E 74
F 79
10 G 78
Blank 72 70
*These tests were repeated due to a suspected procedural error.
TABLE IV
Western Refinery
Settled 14 days at 70F
95% method
75 ppm active treatment
Settled
Treatment Fluid #1 Fluid #2 Fluid #3
A 93
B 98 93 85
C 93
D 92
E 91
F 94
G 92
Blank 92 88 75
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These test results demonstrated that resin alkoxylates with various
alkyl chains and combinations of resins with different alkyl chains are ef-
fective as settling aids. These results also demonstrated that combina-
tions of acid catalyzed resins and base catalyzed resins are effective in
the present invention.
Compound B was selected for further testing because, although it
did not work for the first two applications, other, unrelated treatments work-
ed well there, whereas, for the third application, no better treatment of any
type can be found. This complementarity with alternative treatments made
it the most valuable treatment even though it worked less often.
TABLE V
Different Southern Refinery
Settled 1 day at 170°F
50% and 95% methods
75 ppm active treatment
Treatment 50% Method 95% Method
B 48 55
Blank 46 49
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TABLE VI
Second Mideastern Refinery
Settled 1 day at 200°F
95% method
30 ppm active treatment
Settled
Treatment Fluid #1 Fluid #2
B 16 21
Blank 17 13
The results in Tables V to VII demonstrate the effectiveness of the
base catalyzed nonylphenol-formaldehyde resin ethoxylate at accelerat-
ing settling on a broad range of slurries and at lower (30 ppm) treatment
dosages. Compounds such as these are commercially available, for
example from BASF Corp. as Pluradyne DB-7935.
TABLE VII
Third Mideastern Refinery
Settled 1 day at 160pF
90% method, average of duplicates
75 ppm active treatment
Treatment % ettled
B g5
Blank 66
While this invention has been described with respect to particular
embodiments thereof, it is apparent that numerous other forms and modi-
fications of this invention will be obvious to those skilled in the art. The
appended claims and this invention generally should be construed to
cover all such obvious forms and modifications which are within the true
spirit and scope of the present invention.
