CA1254849A - Process for the removal of solids from an oil - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A process for removing suspended solids particularly difficultly filterable inorganic solids from an oil obtained as a refinery process bottom fraction from both steam and catalytic cracking units (e.g. catalytic cracker bottoms) or from coal conversion processes (e.g.
coal tar) by adding to the oil an agglomerating agent comprising an oxyalkylated phenol formaldehyde resin glycol ester whereby said solids are clustered together into readily filteraole agglomerates.

Description

FIELD OF THE INVENTION
1 This invention is concerned generally with the

2 removal of suspended solids from an oil. More parti-

3 cularly it relates to a process for producing a solids-

4 reduced hydrocarbon oil in which suspended solids in the oil are agglomerated by adding to the oil a solids 6 aggiomerating agent comprising an oxyalkylated glycol 7 ester and separating the agglomerated solids from the oil.
8 BACKGROUND OF THE INVE~NTION
9 A number of processes in petroleum production and refining, coal conversion and the chemicals industry 1I produce as by-products liquid hydrocarbons containing 12 insoluble solid particles oftentimes in the For~m of fineiy 13 divided suspended inorganic solidsO
14 Among the processes wnich produce liquid hydro-carbons containing appreciable amounts of finely divided 16 suspended solids are steam cracking, catalytic crackingg 17 coal gasification9 coke production, and liquification of 18 coal.~ Steam cracking produces a steam cracking tar which 19 contains insoluble particles of coke generally at a level of 0,001 to 5.25~ with the remainder being useful heavy 21 liquid hydrocarbons. Catalytic cracking produces cat 22 cracker bottoms which contain catalyst fines gen0rally at 23 a le~el~ of 0.1 to 5 wt.~ with the remainder being useful 24 heavy liquid hydrocarbons. Liquefication of coal, such as by ~the donor solvent technique as described in U.S.
26 Patents 4,085,031; 4,253,937; 4,048,054 and 4,045,328, 27 produces a solvent-coal slurry containing insoluble 28 particles. Other liquids from coal are praduced in its 29 conversion processes by, for example, in its gasification, coke preparation and other procPsses involving the 3;1 pyrolysis of coal~ These liquid hydrocarbon streams con-32 tain insoluble particles which are desirably removed or 33 reduced in level to allow for their use as a flJel oil or 34 as a feedstock for producing other products.

~ ~, ,, ~æ~949 1 These liquid hydrocarbon streams ofterltirne~ are 2 routed to a settling tank wherein the solid particles 3 (catalyst fines, coke, inorganic matter, are allowed to 4 gravity settle over an extended period of time wherPby an upper layer of substantially particle-free liquid hydro-6 carbons can be decanted off for product use. Settling of 7 the particles may also be provided for in intermediate or 8 shipping tanks. Unfortunately gravity settling is too 9 slow for the reFinery, coal conversion and chemical processes now in use.
ll Improved techniques which are in use include 12 electrofiltration9 filtration and centrifugal separation~
13 The latter two approaches appear to have a low capacity or 14 throughput and a high capital cost. Electrofiltration was handicapped by lack of a regenerable filter media ~hich is 16 stated to have been overcome by the use of hard, smooth 17 spherical glass beads as taught in U.S. Patents 3,799,85S
18 and 3,799,856. Unfortunately these techniques are further 19 limited since the typical oil-suspendible solids have average diameters of size below about 100 microns 21 (commonly described in the art as difficultly filterab~e 22 solids) which size makes satisfactory separation by 23 mechanical separation techniques, including filtration9 24 centrifugation and settling difficult to impossible.
Chemical treatments for oil containing suspended 26 solids have been proposed in the art but, in general, each 27 method suffers from some disadvantage as seen from the 28 prior art discussion of U.S. Patent 4,094,770 wherein the 29 patentee has taught a process for separating suspended unfilterable particulate solids from an oil by agglom-31 erating the solids by means of an agglomerating agent 32 comprising a mixture of acetone and 2-butanone.
33 In U.S. Patent 4,029,567 an agglomerating agent9 34 especially ethanolamine is used to help separate the mineral solids and undissolved coal particles From a 36 solution of coal liqllification products.

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1 Gravlty settling can also be enhancecl by th 2 presence of a surface-active agent as taught in U.S.
3 2~952~620 wherein ~olid particles of a silica--alumina 4 cracking catalyst suspended in a heavy gas oil was separated from the oil by treating the suspension with an 6 aqueous solution of a nonionic surface-active agent e.g. a 7 condensation product of diisobutyl phenol and 9-10 moles 3 of ethylene oxide.
9 Gravity settling can be induced by use of a settling vessel in which the hydrocarb~n oil containing 11 the solids is subjected to a temperature gradient (see 12 U~S~ 4~048~063)~
13 The dedusting of solids-containing hydrocarbon 14 oils such as these derived from oil shale is accomplished lS by the use of various surface active agents (see U.S, 16 4~4~7~7û7)o 17 The use of gravity settling additives and 18 techniques have enhanced the settling rate whereby gravity 19 settling became a feasible method for removal of suspended solids requiring little additional capital investment, a 21 mechanically simple operation and readily modified by 22 change~of the additive, 23 It is the object of this invention to enhance 24 the gravity settling rate of suspended solids from hydro-carbon oils by use of an improved agglomeration aid alone 26 or in combination with other additives.

28 It has been discovered that the residual hydro-29 carbon oils from petroleum and coal conversion processes9 for example hydrocarbon oils boiling in the range of about 31 200C to 550C, can be readily reduced in solids 32 preferably inorganic solids content to an oil having less 33 than 50û weight parts per million (WPPM) of filterable 34 solids when admixed with frorn 25 to 1000, preferably 50 to 250 ppm of a ethoxylated-propoxylated C4-Cg alkyl phenol , D .

1 formaldehyde resin glycol ester of 2,000 to 8,000 M~l at 2 a temperature of from 35 to 210C and allowecl to gravity 3 settle for from 0.3 to 10 days.
4 In accordance with the object of this inventiorl there is provided a proress for reducing the ash content 6 of a hydrocarbon oil fraction comprising:
7 providing a hydrocarbon oil fraction having an 8 ash content greater than 0.02 weight percent and boiling 9 in the range of from about 200~ to about 550C;
treating said cat cracker bottom fraction with ll at least 10 weight parts per million of an oxyalkylated 12 phenol formaldehyde resin glycol ester; and, 13 recovering a deashed hydrocarbon oil portion 14 having a reduced ash content of filterable solids~
lS The agglomeration aid is of the class of oxy-16 alkylated phenol formaldehyde resin glycol ester of Mw 17 ranging from 500 to 50,000, preferably 2,000 to 15tOOO~
18 optimally 5,000 to 8,000.
19 ~'referred is said ester which is the reaction praduct of a phenol formaldehyde resin and propylene oxide 21 which product is then reacted with ethylene oxide and 22 finally esterified as by reaction with maleic anhydride or 23 succinic anhydride which collectively is designated herein 24 ag a succinate.
~ DETAILED DESCRIPTION OF THE INVENTION
26 Within the steam cracking reaction or the 27 catalytic cracking reactor, the liquid hydrocarbon feed-28 stock is subjected to processing conditions of elevated 29 temperature and sometimes elevated pressure to accomplish the desired cracking. The resultant effluent of the 31 reactor is then fractionated into the desired fractions of 32~ gases~ ht liquid hydrocarbons and heavy liquid hydro-33 carbons, w.ith the heaviest and highest boiling fraction 34 being the steam cracker tar or the cat cracker bottoos which cont~lin the insoluble particles. The coal liquifi-36 cation process involves contacting particulate coal with a 37 hydrogen (e.g. a hydrogen donor solvent) under liquifica-, ~.

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l tion conditions producing a hydrocarbon stream containing 2 insoluble particles~ The hydrocarbon strearn can he frac-3 tionated to produce gases, liyht liquid hydrocarbons and 4 heavy liquid hydrocarbons with the heaviest fraction being the bottoms containing the particles. Other liquids from 6 coal are produced by coal conversion process utilizing the 7 pyrolysis oF coal~
8 The gasification of low BTU caal to supply fuel 9 gas for boilers7 kilns and process furnaces was widespread until low cost natural gas became available~ The natural 11 gas curtailments in the early 1970s along with the rapid 12 rise in natural gas prices have reawakened interest in 13 industrial coal gasification to provide Fuel gas For kiln 14 operations9 heat treating furnaces~ boilers and industrial heating. The gasiFication process yields- a hot raw 16 producer gas which upon quenching yields varying amounts 17 of coal tar. Since the coal tar has wide industrial 18 applications both for tar~based chemical and oharma-19 ceutical products and for fuels9 it is highly desirable to reduce the inorganic ash content of these tars. Similarly 21 in the production of coke9 the gas derived from the 22 carbonization of the coal into coke can contain signifi-23 cant amounts oF coal tar which is recovered and similarly 24 processed.
Thus, this invention broadly treats any liquid 26 hydrocarbon stream containiny insoluble solids or par-27 ticles particularly fine inorganic solid~ and liquid 28 hydrocarbons to remove or substantially reduce the solids 29 content of the hydrocarbon oil and is particularly 3û applicable to oils containing finely divided suspended 31 solids, optimally so when these solids can be bonded 32 together by the agglomeration aid bridging through a 33 hydrogen bonding mechanism.
34 Finely divided oil-suspended solids, in general9 are efFectively removed from the oil by the process of the 36 inventian. Those common properties which engender oil 37 suspendability of these particles, for example particle , ~ : .

1 size? density, charge and the like, are also beLieved to 2 render them susceptible to efFective agglomeration and 3 removal by the present process. Representative ~olids 4 include mineral ash-forming impurities, coal coke, carbonaceous solids, catalyst and spent shale fines1 6 natural and synthetic mineral oxides, organic and 7 inorganic salts mixtures thereof and the like in parti-8 culate form and For the unfilterable solids sized in the g average diameter range below about 100 microns, especially below about 60 microns.
11 Representative suspended-solids-containing oils 12 suitable for use herein include shale oil, coal liquefac-13 tion oils as from extraction3 hydrogenation? thermal 14 treatment and combinations thereoF, coal tars from coke manufacture, tar sand oils, petroleum refinery-decant oils 16 such as fractionator bottom oils from a fluid catalytic 17 cracking process bottoms fractions of said oils, resids~
18 mixtures thereof~ and the like oils.
19 These hydrocarbon oils are most effectively treated by the invention when a fraction boiling in the 21 range of 200C to 550~C with a total insoluble solids 22 content greater than about 1,000 WPPM, e.g. from 1,000 to 23 S0,000 WPPM more normally an insoluble solids content in 24 the range of 2,000 to 1û,000 WPPM.
The Agglomeration Aic!
26 A prime feature of the present process is the 27 discovery of a unique solids-agglomerating agent. A
28 solids-agglomerating agent9 to be useful and effective in 29 this service, must promote essentially complete removal of solids from an oil and at the same time must leave the oil 31 virtually intact. In general, known solvents employed for 32 recover.ing solids from an oil do not meet the latter 33 requirement~ The failure of these solvents is manifest in 34 their inability to effectively solubilize both 3S paraffinic-type hydrocarbons and asphaltene-type hydro-36 carbons. Of course it must be apparent that the most 37 difficultly filterable solids are the inorganic particles .~ ~
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~Z548D~9 1 for which the solvent approach is of no value. In 2 addition9 an appreciable portion of the oil is usually 3 rejected (a loss to the process of desirable product 4 precursors) in the form oF tacky or flocculent solids.
It has been discovered that a oxyalkylated alkyl 6 phenol formaldehyde glycol resin ester of ~w ranging 7 from 500 to 50,000, preferably 2,000 to 15,ûO0, optimally 8 from 5,000 to 8,000, when used in admixture with the g solids containing hydrocarbon oil in amounts ranging from 10 to 1,000, preferably 25 to 250, ppm based on the weight 11 of said oil markedly enhances the gravity settling of said 12 solids so that in from 0.3 to 10 days the solids content 13 oF said oil is reduced to less than about 500 WPPM.
14 Preferred for use as an agglomeration aid is an ethoxy-lated propoxylated C4-Cg alkyl phenol Formaldehyde resin 16 ester of a C4-C10 dicarboxylic acid anhydride, e.g. maleic 17 or succinic anyydride. Such a material is commercially 18 available as 454-D (70~ active dissolved in heavy aromatic 19 naphtha) sold by Aquaness Chemical Co. Houston, Texas as a demulsifier for oil field applications.
21 In the event that the solids-containing hydro-22 carbon contains from 0.05 to 50 weight percent or greater 23 of water, it is useful to supplement the agglomeration aid 24 with from 0.5 to 5 parts by weight of a water shedding additive for each part by weight of said agglomeration 26 aid. Since the water may provoke foaming silicone 27 defoamants may be also added as well as other nonionic and 28 anionic surfactants. All Mw given herein are weight 29 avsrage molecular weights as determined by gel permeation chromatography.
31 Agglomeration Conditions 32 Agglomeration conditions for use in the process 33 of the invention will vary depending upon such process 34 Factors as the type and solids content of the hydrocarbon 35 oil, the size distribution of the solids and the proper-36 ties of the oil being processed. in general, the most 37 satisfactory process temperature will range from 35C to t~ ~$~

l 250C, preferably from 50C to 225C ancl optimally frnm 2 75C to 210C. In general the process residence time 3 required to reach the desired ash level of less than 0.05 4 wt percent will range broadly from 0.3 to 1U, more usually 2 to 5, days.
6 The agglomeration aid and, if desired9 the 7 supplemental additives such as a water deshedding aid are 8 introduced into the hydrocarbon oil stream to be treated g prior to or at the point at which said stream is intro duced into the top of the settling tankO The product of ll the process is withdrawn from a point intermediate (on the 12 side) while the solids settle by gravity to the bottom of 13 the tank. The flow rates and unit sizings in the process 14 system are adjusted to provide the desired residence time in the settling tank. The settled solids in the sPttling 16 tank are withdrawn generally as a sludge for direct 17 disposal or Further treatment to recover additional 18 hydrocarbon oil.
l9 The following examples are provided to illustrate the embodiments of the invention and are not 21 intended to limit it in any way.

23 In each of these, hydrocarbon oil bottom 24 fractions (oobtained from four different refineries) having suspended solids with the followin~ general phyaical 26 characteristics were used:
27 Table I
28 Physical characteristics ~ ... . ..
29 Viscosity cst at 210F 8-10 Ash content, wto 0.01-0.02 31 Coking value (WtD) 6.5 -7.2 32 Asphaltene (n-heptane 33 insolubles),~ 0.5 -1.5 34 Toluene insolubles (0.35)~O 0.1 -0.2 Number averag0 mol. wt. 250 -300 36 Filterable solids (WPPM) 1000 -50,000 ~J~

1 The hydrocarbon oil bottom Fraction obtained 2 from the refinery was charged into a kilogram glass 3 reactor which was electrically heated and equipped with a 4 mechanical ayitator. The 200 ml charge of oil was pre~
treated by heating to 80C prior to admixture with a olend 6 containing the indicatecl agglomeration aid at a blend 7 treat rate of 500 ppm for the oils from ReFineries Nos.
8 1-3 and at both 'lO0 and 200 ppm for the oil from Refinery 9 No. 4. The treated charge was allowed to agitate for 2 minutes and then settle for 72 hours while holding the ll temperature at 79C9 thereafter 50 ml was drawn off from 12 the upper region of the reactor and subjected to filtra 13 tion to determine the filterable solids in weight parts 14 per million (WPPM) according to the following technique.
The 50 ml sample is weighed as is the Filter 16 paper (0.8 microns pore size) used for the testO The 17 sample is preheated to 70-30~C, then mixed with 150 to 200 18 ml of hot xylene (heated above 55C) and the admixture 19 poured into the vacuum filter. The container and filter Zû p~per are fully rinsed with hot xylene and thereafter with 21 heptane. The now fully rinsed paper is dried at 82C for 22 30 minutes and then placed in a desideator for 30 minutes.
23 The weight of the solids found on the filter paper 24 provides tha means for measuring the weight parts per million (WPPM) of filterable solids of the original 26 sample.
27 The samples obtained from four different 28 refineries and treated according to the process of this 29 invention are set forth in Table II with nonenhanced, i.e.
untreated, samples in WPPM shown for reference points.

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l _amples 36-49 2 In these Examples coal tar samples from three 3 different nines were processed according to this :invention ~ and evaluated by comparison with non-enhanced 7 i ~ e.
untreated, samples ln WPPM according to the following 6 procedure.
7 Each coal tar sample was charged into a kilogram 8 glass reactor which was electrically heated and equipped 9 with a mechanical agitatorO Each 200 ml charge of coal tar pretreated by heating to 8ûC prior to admixture with ll a blend containing the indicated ayglomeration aid at a 12 blend treat rates of 27 ppm and 135 ppm. Each treated 13 charge was allowecl to agitate for 2 minutes and then 14 settle for 72 hours while holding the temperature at 793C, thereafter 50 ml was drawn off from the upper region of 16 the reactor and subjected to filtration to determine the 17 ~ilterable solids in weight parts per million (WPPM) 18 according to the hot xylene-filtration technique discussed l9 and used in Examples 1-350 20~ The weight of the solids found on each filter 21 paper provided the means for measuring the weight parts 22 per million (WPPM) of filterable solids of the original 23 sample.
24 The coal tar samples obtained from three dif~erent coal mines had the ~ollowing typical analyses.
26 Table III
27 Coal Tar S ~

-29 flash Point ~C 1û2 111 93 30 Pour Point C 32 35 16 31 Viscosity at 50C
32 Kinemat.ic (cs) 86.83 48.94 430.7 33 Z Hydrogen 9.23 7.48 6.40 34 ~ Carbon 77.22 74.û9 69.83 35 ~ Nitrogen 0.43 1.15 1.16 36 ~ Moisture 9.31 1û.5 12.07 37 ~ Ash n . 02 û.û9 0.28 ' `~

l These 3 samples were treated according to the 2 process of this invention with Blend ~1 (Blencl Q ~odi.fied 3 by the presence oF 11.7 wt.~ of water shedding additives 4 [oxyalkylated reslns] and 0.5 wt.~) and the results are set forth in Table IV as Examples 37-39, 41-44 and 46-49 6 along with comparative results from non-enhanced, i.e.
7 untreated, samples as Examples 36, 40 and 45 in WPPM shown 8 for reference points.
9 rable IV
Treated Sample ll Yol ~ H20 Solids Content 12 Rate Add to Coal WPPM
13 Exam. Additive PPM Tar Sample A B C
14 36None - 014,608 37 Q1 100 02,313 16 3~ Q1 100 52,286 17 39 Q1 500 0a, 024 18 39 Q1 500 57,7B7 l9 40None 0 9,633 41 Q1 100 0 9,500 21 42 Q1 100 5 7,990 22 43 Q1 500 5,106 23 44 Q~ 500 5 4,026 24 45None o o 136,000 26 47 Q1 100 5 108,400 27 48~~1 500 108,000 28 49 Q1 500 5 122,560 29 The data reoorded in Table III clearly shows the marked reduction in filterable solids content when the 31 process of the invention is followed but with a hydro-32 carbon liquid of a Kinematic viscosity in centipoises (cs) 33 at 50C of no greater than 330, preferably less than 300, 34 and optimally less than 200. Since the coal tar samples 35 ~lready contairled from 9 to 12o water no advantage 36 resulted From adding 5O more water. It appears that the .

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1 agglomeration process i.s preferably carried on the liquid 2 hydrocarbon containing 2 to 30~ optimally 5 to 15~
3 weight percent water based on the weight of the liquid 4 hydrocarbonO
The invention in its broader aspect is not 6 limited to the specific details shown and described and 7 departures may be made from such details without departing 8 from the principles of the invention and without sacri-9 ficing its chief advantages.

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Claims (9)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for reducing the particulate solids content of a hydrocarbon oil fraction comprising:
providing a hydrocarbon oil fraction boiling in the range of from about 200°C to about 550°C;
treating said hydrocarbon oil fraction with an agglomeration aid wherein the resulting mixture contains from 10 to 1000 weight parts per million of said aid based on the total weight of said mixture, said agglomeration aid comprising oxyalkylated phenol formaldehyde resin glycol ester of ?w ranging from 500 to 50,000; and, recovering a hydrocarbon oil bottoms portion having a reduced content of filterable solids.

2. The process of claim 1 wherein said bottom fraction had at least 1000 weight parts per million (WPPM) of filterable solids and said recovered portion had less than 500 WPPM.

3. The process of claim 1 wherein said aid is an ethoxylated-propoxylated C4-C9 alkyl phenol formal-dehyde resin glycol ester of a ?w ranging from 2,000 to 15,000.

4. The process of claim 1 wherein said treating is at a temperature of from 35°C to 250°C and for residence times ranging from 0.3 to 10 days.

5. The process of claim 1 wherein said frac-tion is a refinery bottoms fraction.

6. The process of claim 1 wherein said frac-tion is coal tar having a Kinematic viscosity at 50°C of no more than 330 centistokes.

7. The process of claim 2 wherein said aid is a succinate and present in said mixture in from 10 to 250 ppm.

8. The process of claim 5 wherein said solids are predominantly catalytic cracker fines having a diameter of less than 100 microns.

9. The process of claim 6 wherein said solids are substantially all inorganic solids.