CA1210729A - Process for the removal of solids from an oil - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A process for removing suspended solids from an oil by adding to the oil an agglomerating agent comprising an oxyalkylated phenol formaldehyde resin glycol ester whereby said solids are clustered together into readily filterable agglomerates.

Description

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PROCESS FOR T~E REMOVAL OF SOLIDS FROM AN OIL
FIELD OF THE INVENTION
1 This invention is concerned generally with the 2 removal of suspended solids from an oil. More particular-

3 ly it relates to a process for producing a solids--reduce~

4 oil in which suspended solids in the oil are agglomerated by adding to the oil a solids-agglomerating agent comprising an 6 oxyalkylated glycol ester and separating the agglomerated 7 solids from the oil.

8 BACRG_OUND OF TEIE INVENTION
9 A number of processes in petroleum production and refining and the chemicals industry produce as by-products 11 liquid hydrocarbons containing insoluble solid particles 12 often times in the form of finely divided suspended solids.
13 Among the processes which produce liquid hydro-14 carbons containing appreciable amounts o~ finely dividea i5 suspended solids are steam cracking, catalytic cracking and 16 liquiric2tion of coal. Steam cracking produces a steam 17 crackin~ tar which contains insoluble particles of coke 18 generally at a level of 0.001 to 5 25.% with the remainder 19 being useful heavy liquid hydrocarbons. Catalytic cracking produces cat cracker bottoms which contains catalyst fines 21 generally at a level of 0.1 to 5 wt.% with the re~ainder being 22 useful heavy liquid hydrocarbons. Liquification of coal, 23 such as by the donor solvent technique as described in U.S.
2~ Patents 4,085,031; 4,253,937; 4,048,0 54 and 4,045,328, prodllces a solvent-coal slurry containing msoluble particles.
26 Other liquids from coal may be produced by, for example 27 pyrolysis of coal. These liquid hydrocarbon streams contain 28 insoluble particles which are desirably removed or reduced in 29 level to allow for their use as a fuel oil or as a feedstock for producing other products.
31 The liquid hydrocarbon str~ams which contain the 32 insoluble particle may be routed to a settling tank wherein 33 the solid particles (catalyst fines, coke, inorganic matter, ~L21~ ~9 1 etc.) are allowed to settle by gravity with the upper lay~r 2 of substantially particle-free liquid hydrocarbons being 3 decanted off for product use. Settling of the particles may 4 also occur in intermediate or shipping tanks. Unfortunately gravity settling is too slow for the reinery and chemical 6 processes now in use.
7 Other techniques include electrofiltration, fil 8 tration and centrifu~al separation. The latter two ap-9 proaches appear to have a low capacity or throughput and a high capital cost. Electrofiltration was handicapped by lack 11 of a regenerable filter media which appears to have been met 12 by the use of hard, smooth spherical glass beads as taught in 13 U.S. Patents 3,799,855 and 3,799,856. These techniques are 14 further limi~ed since typically oil-suspendible solids have average diameters in the range below about lO0 microns and are 16 commonly described in the art as difilcutly filterable solids 17 because, as a practical matter, s~tisfac~ory separation 18 thereof from the oil cannot be accomplished by mechanical 19 separation techniques, including filtra~ion, centrifugation and settling. A variety of treatments for oil containing 21 suspended solids have been proposed in the art but, in 22 general, each method suffers from some disadvantage. These 23 methods are detailed in the prior art discussion of U.S.
24 Patent ~,094,770 wherein the patentee has taught a process fo~ separating suspended unfilterable particulate solids 26 from an oil by agglomerating the solids by means of an 27 agglomerating agent comprising a mixture of acetone and 2-28 butanone.
29 In U.S. Patent 4,029,567 an agglomerating agent, especially ethanolamine is used to help separate the mineral 31 solid~ and undissolved coal particles from a solu~ion of coal 32 liquification products.
33 Gravity settling can also be enhanced by the pre-34 sence of a surface active agent as taught in U.S. 2,952,620 wherein solid particles of a silica-alumina cracking cata-36 lyst suspended in a heavy gas oil was sepaxated from the oil 37 by treating the suspension with an aqueous solution of a ~z~

1 nonionic surface-active agent e.g. a condensation product of 2 diisobutyl phenol and 9-l0 moles o~ ethylene oxide.
3 Gravity settling can be induced by use of a set-4 tling vessel in which the hydrocarbon oil containing the solids is subjected to a temperature gradient (see U.S.
6 4,048,063).
7 The use of gravity settling additives and tech-8 niques have enhanced the settling rate whereby gravity set-9 tling became a feasible method for removal of suspended solids requiring little additional capital investment, a 11 mechanically simple operation and readily modifie~ by change 12 of the additive.
13 It is the object of this invention to enhance the 14 gravity settling rate of suspended solids ~rom hydrocarbon oils by use of an improved agglomeration aid alone or in 16 combination with other additives.
17 SUMM~RY OF TEE INVENTION
18 It has now been discoverea that the residual hydro-19 carbon oils from petroleum processes, for example hydro-20 carbon oils boiling in the range of about 200C to 550C, can 21 be readily reduced in solids content to an oil having less 22 ~han 500 weight:parts per million (WPPM) of filt~rable solids 23 when admixe~ with from 25 to l000, preferably 50 to 250 ppm 24 of an ethoxylated-propoxylated C4-Cg alkyl phenol for-25 maldehyde resin glycol ester of 2000 to 8,000~lw ata tempera-26 ture of from 35 to 210C and allowed to gravity settle for 27 from 0.3 to l0 days.
28 In accordance with the object. of this invention 29 there is provided a process for reducing the ash content of 30 a hydrocarbon oil fraction comprising:
31 provi ing a hydrocarbon oil fraction having an ash 32 content greater than 0.05 weight percent and boiling in the 33 range of from about 200C to about 550C;
34 treating said cat cracker bottom ~raction with at 3s least l0 weight parts per million of an oxyalkylated phenol 36 formaldehyde resin glycol ester; and, 37 recovering a deashed hydrocarbon oil portion hav-1 ing a reduc~d ash content of filterable solids.
2 The agglomeration aid is of the class of oxyal-3 kylated phenol formaldehyde resin glycol esters of Mw ranging 4 from 500 to 50,000~ pre~erably 2,000 to 15,000, optimally S,000 to 8,000.
8 Preferred is said ester which is the reaction 7 product of a phenol formaldehyde resin and propylene oxide 8 which product is then reacted with ethylene oxide and finally 9 esterified as by reaction with maleic anhydride or succinic 0 anhydride which collectively is designated herein as a suc-1 cinate.

13 Within the steam crackin~ reaction or the cata-14 lytic cracking reactor, the liquid hydrocarbon feedstock is subjected to processing conditions of elevated temperature 16 and sometimes ele~ated pressure to accomplish the desired 17 cracking. The resultant effluent of the reactor is then 18 fractionated into the desired fractions of gases, light 19 liquid hydrocarbons and heavy liquid hydrocarbons, with the heaviest and highest boiling fraction being the steam cracker 21 tar or the cat cracker bottoms which contain the insoluble 22 particles. The coal liquification process involves con-23 tacting particulate coal with a hydrogen (e.g. a hydrogen 24 donor solvent~ under liquification conditions producing a hydrocarbon stream containing insoluble paxticles. The 26 hydrocarbon stream can be fractionated to produce gases, 27 light liquid hydrocarbons and heavy liquid hydrocarbons with 28 the heaviest fraction being the bottoms containing the par-29 ticles. Other liquids from coal may be produced by pyroly-sis o coal.
31 This invention broadly treats any liquid hydro-32 carbon stream containing insoluble solids or particles and 33 liquid hydxocarbons to remove or substantially reduce the 34 solids content of the hydrocarbon oil and is particularly applicable to oils containing finely divided suspended so-36 lids, optimally so when these solids can be bonded together 37 by the agglomeration aid bridging through a hydrogen honding 1 mechanism.
2 Finely divided oil-suspended solids, in general, 3 are effectively removed from the oil by the process of the 4 invention. Those common properties which engender oil sus-pendability of these particles, for example particle size, 6 density, charge and the like, are also believed to render them 7 susceptible to effective agglomeration and removal by the g present process. Representative solids include mineral ash-g forming impurities, coal coke, carbonaceous solids, catalyst and spent shale fines, natural and synthetic mineral oxides, 11 organic and inorganic salts mixtures thereof and the like in 12 particulate form and for the unfilterable solids sized in the average diameter range below about lO0 microns, especially 14 below about 60 microns.
Representative suspended-solids-containin~ oils 16 suitable for use herein include shale oil, coal liquefaction oils as from extraction, hydrogenation, thermal treatment 18 and combinations thereof, tar sand oils, petroleum refinery 19 decant oils such as fractionator bottom oils from a fluid 20 catalytic cracking process bottoms fractions of said oils, 21 mixtures thereof, and the like oils~
22 These hydrocarbon oils are most effectively treat-ed by the invention when a fraction boiling in the range of 2~ 200C to 550C with a total insoluble solids content greater 25 than about l,000 WPPM, e.g. from l,000 to 50,000 W~PM more 26 normally an insoluble solids content in the range of 2,000 to 27 lO,000 WPPM.
28 The ~ ratin~ Aid 29 A prime feature of the present process is the 30 discovery of a unique olid~-agglomerating agent. A solids-31 agglomerating agent, to be useful and effective in this 32 service, must promote essentially complete removal of solids 33 from an oil and at the same time must leave the oil virtually 34 in~act. In general, k~own solvents employed for recovering 35 solids ~rom an oil do not meet the latter requirPment. The 36 failure of these solvents is manifest in their inability to 37 effectively solubilize both paraffinic-type hydrocarbons and ~l2~7~

1 asphaltene-type hydrocarbons. In addition, an appreciable 2 portion of the oil is usually rejected ~a loss to the process 3 of desirable product precursors) in the form of tacky or 4 floc~ulent solids.
It has been discovered that a oxyalkylated alkyl 6 phenol formaldehyde glycol resin ester of Mw ranging ~rom 500 7 to 50,000, preferably 2,000 to 15,000, optimally from 5,000 8 to 8,000, when used in admixture with the solids containing 9 hydrocarbon oil in amounts ranging from 10 to 1,000, prefer-ably 25 to 250, ppm based on the weight of said oil marked-11 ly enhances the gravity settling of said solids so that in 2 from 0.3 to 10 days the solids content of said oil is reduced to less than about 500 WPPM. Preferred for use as an 14 agglomeration aid is an ethoxylated propoxylated C4-Cg alkyl phenol formalaehyde resin ester of a C4-C-Io dicarboxylic acid 6 anhydride, e.g. maleic or succinic anhydride. Such a mate-17 rial is commercially available as 454-~ (70~ active dissolved 18 in h*avy aromatic naphtha) sold by Aquaness Chemical Co.
19 Houston, Texas as a demulsifier for oil rield applications.
In the event that the solids-containing hydrocar-~1 bon con~ains ~rom 0.05 ~o 5 weight percent or greater of 22 water, it is useful to supplement the agglomeration aid with 23 from 0.5 to 5 parts by weight of a water sheding additive ~or 24 each part by weight of said agglomeration aid. Since the 2s water may provoke foaming silicone defoamants may be also 2~ added as well as other nonionic and anionic surfactants. All 27 Mw given herein are weight averagP molecular weights as 28 d~termined by gel permeation chromatography.
29 Ag~lomeration Conditions Agglomeration conditions for use in the process of 31 the invention will vary depending upon such process factors 32 as the type and solids content of the hydrocarbon oil, the 33 size distribution of the solids and the properties of the oil 34 beiny proc~ssed. in general, the most satisfactory process 35 temperatuxe. will range from 35C to 250C, preferably from 36 5~ to 225C and optimally from 75C to 210C. In general the 37 process residence time required to reach the desired ash 1 level of iess than 0.05 wt percent will range broadly from 0.3 2 to 10, more usually 2 to 5, days.
3 The agglomeration aid and, if desired, the supple-4 mental additives such as a water desheding aid are introduced into the hydrocarbon oil stream to be treated prior to or at 6 the point at which said stream is introduced into the top of 7 the settling tank. The product of the process is withdrawn 8 from a point intermediate (on the side) while the solids g settle by gravity to ths bottom of the tank. The flow rates 10 and unit sizings in the process system are adjusted to provide 11 the desired residence time in the settling tank~ The settled 12 solids in the settling tank are withdrawn generally as a 3 sludge ~or direct disposal or further treatment to recover additional hydrocarbon oil.
1~ The following examples are provided to illustrate 16 the embodiments of the invention and are not intended to limit 17 it in any way.

19 In each of the following examples, hydrocarbon oil 20 bottom fractions (obtained from four different refineries) 21 having suspended solids with the following general physical 22 characteristics were used:
23 Table I
24 Physical characteristics Viscosity cst at 99C 8-10 26 Ash content, wt% 0.01-0.02 27 Coking value (wt% 6.5 -7.2 28 Asphaltene (n-heptane in-29 solubles),% 0.5 1.5 Toluene insolubles ~0.35), % 0.1 -0.2 31 Number average mol. wt. 250 -300 32 Filterable solicls (WPPM) 1000 -50,000 1 The hydrocarbon oil bottom fraction obtained from 2 the refinery was charged into a kilogram glass reactor which 3 was electrically heated and equipped wi~h a mechanical agi-4 tator. The 200 ml charge of oil was pretreated by heating to ~0C prior to admixture with a blend containing the indicated 6 agglomeration aid at a blend treat rate of 500 ppm for the 7 oils from Refineries Nos.1-3 and at both lO0 and 200 ppm for 8 the oil from Refinery No.4. The treated charge was allowed g to agitate for 2 minutes and then settle for 72 hours while holding the temperature at 79C, thereafter 50 ml was drawn 1 off from the upper region of the reactor and subjected to 2 filtration to determine the filterable solids in weight parts per million (WPPM) according to the following technique.
14 The 50 ml sample is weighed as is the filter paper (0.8 microns pore size) used for the test. The sample is 16 preheated t~ 70-80C, then mixed with 150 to 200 ml of hot xylene (heated above 55C) and the admixture poured into the 18 vacuum filter. The container and filter paper are fully 19 rinsed with hot xylene and thereafter with heptane. The now fully rinsed paper is dried at 82C for 30 minutes and then 21 placed in a disecator for 30 minutes. The weight of the 22 solids found on the filter paper provides the means for 23 measuring the weight parts per million (WPPM) of filterable 24 solids of the original sample.
~5 The samples obtained from four different refi-28 neries and treated according to the proeess of this invention 27 are set forth in Table II with nonenhanced, i.e. untreated, 28 samples in WPPM shown for reference points.

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1 The data recorded in Table II clearly shows the 2 marked reduction in filterable solids content when the pro-3 cess of the invention is followed. The utility of the process 4 is evident in its marked effectiveness for oil bottom frac-tions from each of four different refineries.
~ This invention in its broader aspect is not limited 7 to the specific details shown and described, and departures 8 may be made from such details without departing from the g principies of the invention and without s~rificing its chief 10 advantages,

Claims (5)

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 bottoms fraction comprising:
providing a hydrocarbon oil bottoms fraction boil-ing 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 hav-ing 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 formaldehyde 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 2 wherein said aid is a succinate and present in said mixture in from 10 to 250 ppm.