CA1079973A - Production of synthesis gas and recovery of particulate carbon - Google Patents

Abstract

PRODUCTION OF SYNTHESIS GAS AND
RECOVERY OF PARTICULATE CARBON
(D#74,231-FB) ABSTRACT OF THE INVENTION
This is a process for producing gaseous mixtures comprising H2 and CO which includes the recovery of particulate carbon from the effluent gas stream from a partial oxidation gas generator. Included in the process are the steps of scrubbing the effluent gas with water in a scrubbing zone to form a carbon-water dispersion, and mixing said dispersion in mixing and separating zones with a liquid organic extractant selected from the group consisting of a mixture of liquid organic by-products from oxo or oxyl process, a light liquid hydrocarbon fuel, and mixtures thereof. The aforesaid liquid organic extractant may be obtained subsequently in the process from a thin centrifuge stream of carbon-extractant dispersion, or from a light liquid fraction from a distillation zone, or preferably from both sources.
Make-up fresh extractant from an external source may also be introduced into the system. In the separating zone, a clarified water layer and a carbon-extractant dispersion is produced. Then follows the steps of: separating and recycling said clarified water to said scrubbing zone;
separating said carbon-extractant dispersion and introducing same into a centrifugal separation zone; separately withdrawing from said centrifugal separation zone a thick stream of carbon-extractant dispersion and a separate thin stream of carbon-extractant dispersion; degasifying and introduceing said thin centrifugal stream into said mixing and separating zone as a portion of said liquid extractant, introducing said thick stream of carbon-extractant dispersion in admixture with fresh heavy liquid hydrocarbon fuel e.g. heavy fuel oil into a fractional distillation zone; recycling a light liquid fraction from said distillation zone to said mixing zone as a portion of said liquid organic extractant, and introducing a pumpable bottoms slurry of carbon heavy liquid hydrocarbon fuel from said distillation zone into said synthesis gas generator as at least a portion of the fuel.

Description

10795~73 .

, BACKCROUND ~ THE INVENTION
Field of the Invention: This inventlon r~lates to a f . . .... _ continuous process for rccovering particulate czrbon from synthesls gas, and particularly from carbon-water dispersions.
Description of the Prior Art: Raw synthesls gas leaving a partial oxidation synthesis gas generator comprises principally CO and H2 together with minor amounts of ~nely divided carbon or partlculate carbon. Preferably, the particulate carbon may be removed from the effluent gaseous stream by contacting the gas with water in a quenching and scrubbing zone. The finely divided carbon soot partlcles are wetted by water ~o as to fcrm a mixture of particulate carbon and water. The particulate carbon pro(luced in synthesis gas manufacture is unique and problems associated with the separation o~ synthesis gas carbon are not the same as those encountered in the removal of carbon or solids made by other processes. For example5 the fine carbon particles from partial oxidation are unusual in that they will settle in water to only about 1.0 to 3.0 weight percent, whereas conventional carbon blacks may settle to concentrations of as much as 10 weight percent.
To produce synthesis gas economlcally, it is important to separate clear water from the carbon-water mixture for reuse. However, the fine particle size Or th~
carbon soot makes ordlnary filtration methods difficult and makes gravlty separation uneconomical because of excess ,.

settling times i.e. about 1-2 days. Further, liquid hydro~
c~rbon extraction procedures for recoverlnK particulate carbon s~t such as disclosed in coassigned U.S. Patent

2,99Z,906 to F. E. Guptill, Jr. require large volumes of extractant. This in turn requires larger sized auxilliary process equipment. Further, under some conditions trouble-some emulsions which are difficult to separate may form ; upon the addition of a gas to the oil-carbon dispersion.
By the process of our invention, particulate carbon is quickly and easily separated from quench and scrubbing water, so as to permit recycle of the clear water and recycle of the extractant.
The oxo process is the commercial application of a chemical reaction called oxonation or, more propcrly, hydroformylation. In this reaction, hydrogen and carbon monoxide are added across an olefinic bond to produce aldehydes containing one more carbon atom than the olefin.
The oxyl process is a method for directly producing alcohols by catalytically reducing carbon monoxide with hydrogen so as to link several partially reduced carbon atoms together. Essentially it is a modified Fischer-Tropsch Process which preferentially produces oxygenated compounds consisting mainly of alcohols.
SUMMARY
- ~n one important aspect, the sub~ect continuous j process relates to a method for producing gaseous mixtures comprising Hz and C0 and recovering particulate carbon therefrom by the steps Or:

(1) reacting by partial oxidation a hydrocarbon-aceous fuel with a free oxygen-containing gas in the re-action zone of a free-flow noncatalytic gas generator at a temperature in the range of about 1300 to 3500F. and a pressure in the range of about 1 to 300 atmospheres in the presence of a temperature moderator to produce an effluent gas stream comprising H2, CO, CO2, H20, entrained parti-culate carbon and at least one member of the group H2S, COS, CH4, A and N2;
(2) introducing said effluent gas stream into gas-cooling and gas-scrubbing zones in which the gas stream is cooled and contacted with water so as to effect the removal of said particulate carbon from said effluent gas stream and to produce a carbon-water dispersion;

(3) removing gaseous impurities from the gas stream leaving (2) producing a product gas stream comprising H2 and CO;

(4) contacting said carbon-water dispersion in a mixing zone with a liquid organic extractant from the group consisting of a light liquid fraction obtained from the distillation zone in (6), a thin centrifuge stream of carbon-extractant obtained from the centrifugal separating zone in

(5), and mixtures thereof; wherein the amount of said liquid organic extractani added to said carbon-water dispersion is sufficient to render all of the carbon particles in said carbon-water dispersion hydrophobic and to resolve said carbon-water dispersion, and removing a stream of clarified water and a separate stream of carbon-extractant dispersion containing about 0.5 to 5 weight percent carbon in a separating zone '- ' at a temperature in the range of about ambient to 700F.
and a sufficient pressure to maintain said liquid organic . extractant and said clarified water in liquid phase, ay in the range of about 1 to 200 atmospheres depending upon temperature;
(5) introducing said carbon-extractant dispersion s from (4) into a centrifugal separating zone at a temperature f in the range of about ambient to 700F. and a pressure in the range of about 1 to 200 atmospheres, separately with-i drawing from said centrifugal separating zone a thick centri-f~ fuge stream of carbon-extractant dispersion having a carbon content in the range of about 1 to 10 weight percent, and a thin centrifuge stream of carbon-extractant dispersion having a carbon content in the range of about 0.05 to 1.0 weight percent; degasifying said thin centrifuge stream if necessary;
withdrawing a partially clarified water stream from said r, separating zone, and recycling said water to said gas-scrubbing zone in (2) to scrub carbon from the effluent gas stream from the gas generator; introducing said thick centrifuge stream of carbon-extractant dispersion in admixture with fresh heavy liquid hydrocarbon fuel into a fractional distilla-¦- tion zone; and , (6) removing a light liquid fraction from said , distillation zone and introducing either said light liquid ,:. fraction or said thin centrifuge stream from (5), or both r' of said streams into said mixing zone in (4) as previously '. described as said light liquid extractant; and removing from said distillation zone a pumpable bottoms carbon slurry, and ,~ introducing same into said gas generator as at least a portion of said fuel.
,:. _5_ The synthesis gas may be produced at the proper pressure and ~2/CO mole ratlo for ~irect feeding int~ an oxo or oxyl process. Advantageously, a mixture of liquid organic by-products produced in said oxo or oxyl process may be easily disposed Or ln the synthesls gas generator as a portion of the fuel.
DESCRIPTION OF THE INVENTION
Synthesis gas preferably comprises H2 and CO
and may contain relatively small amounts of C02~ H20, CH4, H2S, N , COS, A, particulate carbon and fuel ash. It may be made by the partial oxidatlon of a hydrocarbonaceous fuel in a free-flow synthesis gas generator. For example, a liquid hydrocarbon fuel such as fuel oll is reacted wi,h a free-oxygen containing gas and steam at an autogenously maintained temperature within the range of about 1300 to 3500F and a pressure in the range of 1 to 300 atmospheres.
By scrubbing the effluent gas stream from the gas generator with water in a gas scrubblng zone, particulate carbon may be removed from the gas stream as a pumpable carbon-water dispersion containing about 0.5 to 3 weight percent carbon. This carbon-water dispersion is then - treated with a liquid organic extractant to separate the carbon from the water. The liquid organic extractant may be selected from the group consisting of a mixture of liquid organic by-products from oxo or oxyl process, a .

light liquid hydrocarbon fuel, and mixtures thereof. The aforesaid liquid organic extractant may be obtained sub-sequently in the process from a thin centrifuge stream of carbon-extractant dispersion, or from a light liquid frac-tion from a distillation zone, or preferably from both sources. Make-up fresh extractant from an external source may also be introduced into the system. The light liquid hydrocarbon fuel is described more fully later and may be selected from the group butanes, pentanes, hexanes, gaso-line, kerosene, naphtha, light gas oils, and mixtures thereof.
The amount of liquid organic extractant introduced is sufficient to render all of the carbon particles in the carbon-water dispersion hydrophobic and to reRolve the carbon-water dispersion. As further described below, the extractant may be added in one or two stages. The liquid extractant forms with the carbon from the carbon-water ; dispersion a pumpable carbon-extractant dispersion con-;- taining about 0.5 to 5 wt. % carbon. A clarified water layer separates out in a decanter and falls to the bottom.
The water layer is removed from the decanter and may be recycled to the scrubbing zone. The carbon-extractant dispersion which forms and floats on the water layer is removed and concentrated in a centrifugal separation zone.
The carbon-extractant liquid dispersion that is ; removed from the decanter is concentrated bv means of centrifugal separation in a commercial centrifuge. Advan-tageously, by removing a portion of the liquid extractant in - the overhead stream from the decanter by centrifugal separation, the size and heat duty of the extractant , stripper used downstream in the process may be reduced.
Simultaneously, a thin centrifuge stream of extractant containing a minor amount of carbon is produced. This , thin centrifuge stream is then recycled to the mixer or to the decanter, or both to resolve the carbon-water dispersion.
Industrial centrifuges such as described in Perry's Chemical Engineers' Handbook, by Perry, Chilton, and Xirkpatrick, Fourth Edition, McGraw Hill, Pages 19-86 to 19-100, employ centrifugal acceleration which is many times the gravitational acceleration. Centrifugal force causes sedimentation of solid particles through a layer of liquid or filtration of a liquid through a bed of porous solids. Centrifugal force, commonly expressed in ~, multiples of the standard force of gravity, varies with j~ the rotational speed and with the radial distance from ,;~ the center of rotation.
, ~ Disc centrifuges for example illustrated in Figure 19-139 of Perry's Chemical Engineers' Handbook develop 4,000 to 10,000 times the force of gravity. Disc ' centrifuges have bowl diameters in the range of about 7 to 32", a disc spacing in the range of about 0.015 to 0.50 inches, a number of discs in the range of about 30 to 130, and a disc half angle in the range of about 35 to 50. Disc centrifuges and other conventional centri-fuges are suitable for use in the subject process.

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-lV79973 ;

The heavy (thick) centrifuge stream in admixture withheavy liquid hydrocarbon fuel is introduced into a conven-tional fractional distillation zone. The ratio of heavy liquid hydrocarbon fuel to light liquid extractant in the thick centrifuge stream is in the range of about 0.02 to 40 lb. per lb. For example, a light liquid hydrocarbon fuel fraction having an atmospheric boiling point in the range of about 100 to 500F may be removed from said distillation zone, cooled, liquefied, and recycled to said mixing zone as at least a portion of the extractant.
The total amount of light liquid fraction from the distillation zone that is introduced into the decanter either in one or two-stage embodiments may be about 0.05 to 20 parts by weight of light liquid fraction per part by weight of thin centrifuge stream comprising carbon-extrac-tant dispersion. In two-stage decanter operation, prefer-, ably all of said thin centrifuge stream is introduced into the decanter in the second stage. However, a small portion i.e. up to 25 wt. % of the total amount of thin centrifuge stream may in addition be introduced into the mixing zone inthe first stage in addition with said light liquid fraction.
However the thin centrifuge stream may be introduced into the first stage only in another embodiment.

_g_ ~(~79973 Whe the liauid organic extractant comprises said light liquid hydrocarbon fuel then said pumpable liquid bottoms carbon slurry from said distillation zone comprises particulate carbon from said carbon-extractant dispersion and the unvaporized portion of said heavy liquid hydrocarbon fuel. This carbon slurry may be introduced into said synthesis gas generator as at least a portion of the feed.
Alternatively, when the liquid organic extract-ant compDises a mixture of liquid organic by-products from an oxo or oxyl process, then said pumpable liquid bottoms carbon slurry from said distillation zone ; comprises particulate carbon, the unvaporized portion of said heavy liquid hydrocarbon fuel, and the unvaporized portion of said liquid organic-by-products from the oxo or oxyl process. This carbon slurry may be introduced into said synthesis gas generator as at least a portion j of the feed.
Heavy liquid hydrocarbon fuels suitable for ùse in this process include for exa~ple, heavy distillates, residual fuel oil, bunker fule oil, No. 6 fuel oil, and mixtures thereof. The carbon contetn of said bottoms slurry in wt. % in the range of about 0.5 to 25.
Advantageously, a mixture of liquid organic by-products from an oxo or oxyl process in the amount of about 1 to 99 wt. % of the mixture so produced is mixed with said bottoms slurry. This mixture may be fed to the 1~379g73 synthesis gas generator as feed. Alternatively, t~le mixture may be burned as fuel ln a furnace. The clarified water from the separating zone is optionally purified and recycled to sa~d gas-scrubbing zone to scrub the effluent gas stream from the gas generator.
Gaseous impurities in the effluent gas stream from the synthesis gas generator may be removed in a manner to be more fully descrlbed to produce synthesis eas e.g.
mi tures of H2+C0 having a mole ratio H /C0 ln the range of about 0.9 to 2.0 moles of H per mole of C0. Syntnesis gas may be produced having a specific H2/C0 mole ratio for introduction into said oxo or oxyl process.
In one embodiment of the in~ention, the mixtures ~; of carbon monoxide and hydrogen produced in the synthesis .
gas generator are used as feed to the well known oxo or oxyl ~; catalytic process. Liquid organic by-products from the oxo or oxyl process may be then used as the previously described liquid organic extractant. Further, these liquid organic by-products may be introduced into said synthesis gas generator as a portion of the fuel. Synthesis gas produced by the sub~ect process with a H2/C0 mole ratio in the range of about 1-2 moles of the H2 per mole of C0 are introduced into the oxo process where carbon monoxide and hydrogen are added to an olefin in the presence of a cobalt catalyst at e.g. a temperature in the range of about 100 to 200C and a pressure in the range of about 65 to 300 atmospheres to produce an aldehyde containing one carbon atom more than the original olefin. Thus, a hydrogen atom and formyl group may be added across the double bond of an olefin as ~ho-~n in e-~uation; (1) and (2):

RCH = CH2 + CO + H2~~~ RCH2CH2CH (1) RCH = CH2 + CO + H2 ~ RCH(CHO)CH3 (2) Optionally, normal alcohols may be produced from the normal aldehydes by hydrogenation as shown in equation (3):
RcH2cH2cHo + H2 > RCH2CH2CH2OH (3) The oxo reaction is homogeneously catalyzed by carbonlys of group VIII metals, iron, cobalt, nickel, ruth-enium, rhodium, palladium, osmium, irridium, and platinum.
However, cobalt is the only metal whose carbonyl catalysts are of industrial importance e.g. Co2(CO)8, HCo(CO)4, and Co4(CO)12.
Reaction times vary in the range, of about 5 to 60 minutes. The synthesis gas feed to the oxo or oxyl process contains 1-2 moles of hydrogen per mole of carbon monoxide.
Various olefinic raw materials include ethylene to produce propionaldehyde, propylene to produce butyrald-~- ehyde, and pentylenes, heptylenes, nonylenes, and dodecylenes used to produce higher oxo alcohols. Dimers and trimers of isobutylenes may be used. Straight chain products are favored over branched-chain products. For example, normal but not isobutyraldehyde can be converted into butanol or 2-ethyl-l-hexanol. Lower temperatures and higher carbon monoxide pressure favor the straight-chain isomer.
Processing steps required to produce an oxo product economically include (l) hydroformylation, or oxo reaction in an oxo reactor at a temperature in the range of about 100 - 200C and a pressure in the range of about 65-500 atm; (2) removal of catalyst from the reaction mixture (decobalting); (3) cobalt catalyst recovery and processing s for reuse; (4) aldehyde product refining; and optionally, (5) hydrogeneration at a temperature in the range of about 50-250C, and a pressure in the range of about 50-3500 psi to produce alcohols; and (6) alcohol refining. Oxo products, ~' both aldehydes and alcohols are refined by conventional ;~ distillation equipment. Chemical treatment may be used to remove trace quantities of impurities.
~ The oxyl process as~defined herein is a method t for producing a mixture of oxygenated organic compounds by catalytically reducing carbon monoxide with hydrogen at a temperature in the range of about 175 to 450C and a ' pressure in the range of about 10 to 200 atmospheres. The H2/CO ratio may be in the range of about 0.9 to 2 moles of H2 per mole of CO. Space velocities may range from 100 -;,; 500 SCF of dry feed per cu. ft. of cat. per hr. and higher based on fresh feed. Both fused and precipitated iron catalysts may be used. The iron catalyst may contain copper, calcium oxide, diatomite, and may be impregnated with potassium hydroxide. Iron nitride catalysts may be used.
~i~ 20 The oxyl process for producing alcohols may be illustrated by Equation (4):
2n H2 + nCO--~ CnH2n + 1 + (n-l)H20 (4) ~, The alcohols may be subsequently converted to olefins and , paraffins.
Essentially the oxyl process is a modified Fischer-, Tropsch process which preferentially produces oxygenated ; compounds consisting mainly of alcohols. In addition to predominantly straight chain alcohols and few side chains, by-product esters, other oxygen-containing compounds, par-affins, and olefin hydrocarbons may he produced.

-13~

The olefins may be treated by the oxo process (hydroformy-lation followed by hydrogenation) to increase the yield of alcohols.
For example, a mixture of aliphatic oxygenated ; compounds containing approximately 30% alcohols in addition to acids, aldehydes, olefins, and esters may be produced by converting gaseous mixtures of H2 + CO over alkalized iron fillings at 150 atmospheres pressure and at a temperature of 400 - 450C.
Another oxyl process operates at a pressure in the range of about 10 to 50 atmospheres and at a temperature of about 175 - 230C. Fused iron catalysts of the conven-tional ammonia-synthesis type and high space velocities are used. Gas recycle to increase the catalyst life may be ~- employed: 7-20 volumes of recycle gas per volume of fresh p~ synthesis gas. Straight chain alcohols e.g. up to C12, may be produced by this process.
By-products as defined herein are normally liquid organic co-products formed in the hydroformylation or the oxyl process and consist of liquid organic materials from the group consisting of alcohols, aldehydes, esters, ketones, ethers, acids, olefins, saturated hydrocarbons, and mixtures thereof.
A particular advantage of the subject invention is that the stream synthesis gas may be produced in a syn-thesis gas generator at a proper pressure for use in the , . .

10~9973 OXQ ~r oxyl pr~c~ss. A costly gas compressor may thercby b~ cllm-i nated. Also, the mixture of liquid organlc by-products from the oxo or oxyl process, which may have previously presented a dlsposal problern may be now economically ~lxed with said carbon-heavy liquid hydro-carbon slurry bottoms from the distillation zone and burned in the gas generator as fuel to produce more synthesis gas. The speclfic composition of the mixture of liquid or-ganic by-products from the oxo or oxyl process will depend upon the reaction conditions, the type of reactants, and the procedure used to refine the product. The amount of each constituent in the mixture may be taken from the ranges shown in Table I. This includes whole samples, fractions, and the rar~inate after water extraction. If a group ls present, there may be more than one compound in that group present in the extractant. If for example the mlxture con-tains 65 wt. % of normal and isoalcohols and 5 wt. % of esters, than the total remaining constituents in the mixture cannot exceed 30 wt. %. The term "by-products" includes by deflnition the liquid organic waste products from the oxo or oxyl process which have the compositlon shown in Tables I
and II.

lV79973 TABLE I- INGREDIENTS IN LIQUID ORGANIC BY-PRODUCTS
or oxO or Oxyl Proc~ss _ Group Carbon Range Wt. ~
Alcohols C3 to C 2 to 75 Ester~ C6 to C28 5 to 70 Aldehydes C3 to C16 Nil to 25 Ketoncs C3 to C16 Nll to 25 Ethers C6 to C28 Nil to ~0 Acid~ C3 to C16 Nil to 10 Ole~ins C5 to C15 Nil to 30 Saturated Hydrocarbons C5 to C28 Nll to 50 Water Nil to 15 The ultimate analysla o~ the llquid organic by- -products Or the oxo or oxyl proce~s i8 shown ln Tabl~ II.
Tho elemsnts ~ay be taken ~ro~ the ~ang~8 sho~n 80 long as the total ~t. % i8 100.

TABLE II - ULTIMATE ANALYSIS OF LIQUID ORGANIC BY-PRODUCTS
o~ Oxo or Oxyl Process . - --- .
Wt. %
Ca~bon About 55 to 90 Hydrogen About 5 to 17 Oxygen About 3 to 40 Thc pre~err.~d ~axlmum concentratlon Or organic acid prescnt in the mlxture 1~ le8~ than 5 ~t. %, ~or ~xaople 1-2 wt. %. The organic e~ters are the reaction product~ o~
prlmary saturated alcohols and lo~ ~olecul~r ~elght saturated organlc aclds.
.''' , ' .

.

, ;

The compo~ltlon o~ a typical llquld organlc mixture, as produced ~or example by th~ process shown ln Hydrocarbon Proce~lng, Pag~ 211, November 1969, Cul~
Publlshlng Co., Houston, Te~a3 and co~prislng the liquld organlc by-products o~ an oxo proces~ i8 shown in Tablo III.

TABLE III - COMPOSITION OF TYPICAL MIXTURE
Comprlslng Liquid Organlc By-Produets From Oxo Proeoss Wt. %
Esters 56 ! Ethers 20 Aldehydes 5 Ketone~s 5 ' Aelds 5 and below Saturated hydroearbons 1 and belo~
Olerlns l and below Aleohol 5 Water 2 The esters ln the aroresaid mlxture h~e an j average Cl2 numbor and are rormod by the reaetion o~ C4 to s Cg aleohols and C3 to C8 acids. The ethers are highl~
s branehod hnd havo an average C12 number. The aleohol~
inelude nor~al and lsobutanol and i~opropyl aleohol. The ultimate analysis Or ~ald typleal mixture 1~ qho~n ln Table IV.
. .
TA9LE IV- ULTIMATE ~A~Y8IS Q~ TYrICAL MIXTURE
Comprlsing ~iqu~d Orghnie By-Produets From Oxo Proee~s . Wt. %
Chrbon 69.2 Hydrogen 12.0 o~g~,n. lB.8 ..

~ 1079973 Other properties of said typical mixture are shown i.n Table V.
~;~ TABLE V - Properties of Tyical Mixture Comprising Liquid Organic By-Products From Oxo Process Gravity API 29.2 ~ Density, 0.87 ,~ viscosity, Centistokes ~7 . 68F 4.1 . 122F 2.0 Distillation, ASTM
Vol. % F
~ IBP 290 ,~ 10 326 't' 20 344 , 30 360 , . 50 396 : 90 526 f The synthesis gas generator in my process preferably . consists of a compact, unp~ckedJ free-flow non-catalytic, refrac-, tory lined steel pressure vessel of the type described in coassigned United States Pat. No. 2,809,104 issued to D. M. Strasser et al.
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~ - 18 -,~

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The free-oxygen containing gas may be selected from the group consisting of air, oxygen-enriched air (22 mole percent 2 and higher), and preferably substan-tially pure oxygen (95 mole percent 2 and higher).
Preheating of the reactants is optional but generally desirable. For example, a hydrocarbon oil and steam may be preheated to a temperature in the range of about 100 to 700F. and the oxygen may be preheated to a temperature in the range of about 100 to 750F.
A wide variety of hydrocarbonaceous fuels are suitable as feed stocks for the partial oxidation process, either alone, in combination with each other, or suitably in combination with said carbon-heavy liquid hydrocarbon fuel slurry from the distillation zone. Preferably, from s about .01 to 99 parts by weight of fresh mixture of liquidorganic by-products from an oxo or oxyl process may be mixed with each part by weight of the bottoms product ~- from the fractional distillation zone, to be further de~cribed.
The hydrocarbonaceous fuels include heavy and light liquid hydrocarbon fuels. Included are petroleum distillates and residue, gas oil, residual fuel, reduced crude, fuel oil, whole crude, coal tar oil, shale oil, tar sand oil, and mixtures thereof.
Pumpable slurries of solid carbonaceous feed-stocks i.e., lignite, bituminous and anthracite coals in water or in said liquid hydrocarbon fuels are included - herewith as within the scope of the definition for hydro-carbonaceous fuels which may be fed to the gas generator.
Similarly, pumpable slurries of particulate carbon soot --:L9~
' . -~079973 in a carrier from the group consisting of liquid hydrocarbonfuel or residues thereof, liquid organic b~-products from an oxo or oxyl process or residues thereof, and mixtures thereof are also by definition hydrocarbonaceous fuels which may be fed to the gas generator.
Light liquid hydrocarbon fuel extractant as used herein have the following characteristics: atmospheric boiling point in the range of about lO0 to 500F., degrees API in the range of over 20 to about 100 and a carbon number in the range of about 5 to 16.
Heavy liquid hydrocarbon fuels as used herein have a gravity in degrees API in the range of about -20 to 20.
It is normal to produce from hydrocarbonaceous fuels by partial oxidation about 0.5 to 20 weight percent of free carbon soot (basis carbon in the hydrocarbonaceous fuel). The free carbon soot is produced in the reaction zone of the gas generator for example, by cracking hydro-carbonaceous fuels. Carbon soot will prevent damage to the refractory lining in the generator by constituents which are present as ash components in residual oils. With heavy crude or fuel oils it is preferable to leave about ~- 2 to 3 weight percent of the carbon in the feed as free carbon soot in the product gas. With lighter distillate oils, progressively lower carbon soot yields are taken.

The amount of soot in the product synthesls gas may be eontrolled primarlly by regulatlng the oxygen to carbon ratlo (O/C atom/atom) in the range of 0.7 to 1 5 atoms of oxygen per atom of carbon in the fuel an~ to some extent by regulatlng the weight ratio of ~ O to hydrocarbon fuel in the range of 0.15 to 3.0 pounds of H20 per pound of fuel. In the above relatlonship, the O/C
ratio ls to be based upon (1) the total of free-oxygen atoms in the oxidant stream plus comblned oxygen atoms in ]O the hydrocarbonaceous fuel feed molecules and (2~ the total of car~on atoms ln the hydrocarbonaceous fuel feed plu~
carbon atoms in recycled particulate carbon (soot). Slnce the oxo and oxyl by-products contaln combined oxygen atoms, the requirement of free-oxygen for gasification ls less t~an for ordinary hydrocar~ons. In fact, there is a synergistic effect leading to even lower oxygen consumption then would be expected according to dlrect proportionallty.
H20 is prlnclpally introduced into the reaction zone to help control the reaction temperature, to act as a dlspersant of the hydrocarbon fuel fed to the reactlon zone, and to serve as a reactant to increase the relative amount of hydrogen produced. Other temperature moderators include C02-rich gas,~ a cooled portion of product gas, cooled off-gas from an integrated ore-reductlon zone, nitrogen, and mixtures thereof.

: Many advantages are achieved ln the subJect process by the addition of oxygen containing hydrocarbon naterial, such as found in the liquid organic by~product OI' the oxo or oxyl process~ as a portion of the feed to the synthesis gas generator, For example, for a given level of soot production, the amount of free-oxygen supplied to the reaction zone of the synthesls gas generator, and the steam to fuel welght ratio may be decreased at a substantial cost savlngs.
;

1) The free carbon soot leaving the reaction zone entrained in the stream of product synthesis gas has some uni(lue properties. It is both hydrophilic and oleophllic.
It ls easily dispersed in water and has a high surface rlrea. For example, the speclflc nuri~nce nren of the ~ree carbon .

i, .

soot, as determined by nitrogen absorption, ranges from 100 to 1,200 square meters per gram. The Oil Absorption Number, which is a measurement of the amount of linseed oil required to wet a given weight of carbon soot, ranges from 1.5 to 5 cc's of oil per gram of carbon soot. For further information regarding the test method of determin-ing the Oil Absorption Number see ASTM Method D-281.
Free carbon soot, also referred to herein as particulate carbon, as produced within our process has a particle size in the range of about 0.01 to 0.5 microns and commonly has a particle diameter of about 77 millimic-rons. Free carbon soot comprises about 92 to 94 weight percent of carbon, 0.1 to 4 weight percent of sulfur, and 3 to 5 weight percent of ash. Being formed at high tem-peratures, it is substantially free from volatile matter.
In one embodiment of our invention, the hot gaseous effluent from the reaction zone of the synthesis gas generator may be quickly cooled below the reaction temperature to a temperature in the range of 180 to 700F
by direct quenching in water in a gas-liquid contacting or quenching zone. For example, the cooling water may be contained in a carbon-steel quench vessel or chamber located immediately downstream from the reaction zone of said gas generator. A large diameter dip leg starting at the bottom end of the reaction zone and discharging beneath the water level in the quench chamber serves as an inter-connecting passage between the reaction zone and the quench zone through which the hot product gases pass.

, This passage also serves substantially to equalize the ~ pressure in the two zones. A concentric draft tube, open ;~ on both ends, may surround said dip leg, and create an annulus through which mixture of quenched gas and water rises vigorously and splashes against the support plate . of the reactor floor. The water and gas then separate in the quench chamber in the space outside the draft tube.
The circulation of water through the draft tube system maintains the entire quench system at essentially the tem-perature of the water leaving the quench vessel, which is also the temperature of the saturated steam in the quench zone.
Recycle water from the carbon scrubbing zone, to be further described is normally introduced through a quench ring at the top of the dip-leg to cool the metal at that 'i point. Large quantities of steam are generated in the quench ;~ vessel, and the quench chamber may be likened to a high ~,i :~ output high pressure boiler.
The turbulent condition in the quench chamber, caused by the large volume of gases bubbling up through said annular space, helps the water to scrub a large part of the solids from the effluent gas so as to form a disper-sion of unconverted particulate carbon and quench water.
~- Further, steam required for any subsequent shift convers-ion step is picked up by the effluent synthesis gas during quenching. For a detailed description of the quench chamber, reference is made to coassigned United States Patent No.
2,896,927 issued to R. E. Nagle et al. Any residual solids in the cooled and scrubbed effluent synthesis gas leaving the , ~ - 24 -1079~73 quench chamber may be removed by means of a conventional venturi or jet scrubber, such as described in Perry's Chemical sngineers' Handbook, Fourth Edition, McGraw~
Co., 1963, pages 18-55 to 56.
Alternately, the hot effluent gas stream from the reaction zone of the synthesis gas generator may be cooled to a temperature in the range of about 240 to about 700 F. by indirect heat exchange in a waste heat boiler.
The entrained solid particles may be then scrubbed from the effluent synthesis gas by contacting and further cooling the effluent stream of synthesis gas with quench water in a gas-liquid contact apparatus, for example, a quench dip-leg assembly, a spray tower, venturi, or jet scrubber, bubble plate contactor, packed column, or in a combination of said equipment. For a detailed description of cooling synthesis gas by means of a waste heat boiler and a scrub-bing tower, reference is made to coassigned U.S. Patent No. 2,999,741 issued to R.M. Dille et al.
It is desirable to maintain the concentration of particulate carbon in the gas cooling and scrubbing water streams in the range of about 0.5 - 3 wt.% and preferably below about 1.5 wt. %. In this manner, the dispersion of carbon in water will be maintained sufficiently fluid for easy pumping through pipelines and for further processing.
The temperature in the scrubbing zone is in the range of about 180 to 700F., and preferably in the range about 250 - 550F. The pressure in the scrubbing zone is in the range of about 1-250 atmospheres, and preferably at , ~,~

least 25 atmospheres. Suitably the pressure in the , scrubbing zone is about the same as that in the gas generator, less ordinary pressure drop in the line.
It is important with respect ot the economics of the process that the particulate carbon be removed from the carbon-water dispersion and the resulting clear water to be recycled and reused for cooling and scrubbing additional particulate carbon from the synthesis gas. In one single stage embodiment of the , 10 subject process all of the previously described light liquid fraction from the distillation zone in admixture ~, with all of said thin centrifuge steam may be mixed with the carbon-water dispersion at one time. The carbon water dispersion is thereby resolved and the carbon is separated from the water.. In this embodiment the amount by weight of said mixture of light liquid fraction and thin centrifuge stream that is mixed with said carbon-water dispersion in a mixing zone is in the range of r about 10 to 200 times, and preferably in the range of about 20-100 times the weight of the parti~ulate carbon in the carbon-water dispersion. This amount is sufficient ~- to render all of aaid particulate carbon hydrophobic ', and to resolve the carbon-water dispersion. Clarified water separates from the particulate carbon and a carbon-extractant dispersion is produced. This is a pumpable dispersion of particulate carbon in extractant containing about o r~ 5 to 5 wt. % carbon, and preferably about 0.5 to 3 wt. ~ carbon.
The aforesaid carbon-water dispersion may be contacted with said liquid extractant by any means e.g.

' j.,, iO79973 mixing valve, static mixer, baffled mixer, pump, orifice, nozzle, propeller mixer, or turbine mixer. ~ligh pressure

6 will make possible the use of an extractant having a lower boiling point. High temperature facilitates phase separation.
The mixed stream is passed into a phase separating zone, for example a decanter or tank providing a relatively quiescent settling zone. In the separating zone, also known as a decanter, clarified water sinks to the bottom by gravity.
~ A dispersion of carbon in said light liquid extractant may f 10 float on top of the clarified water. The volume of the settling tank should be sufficient to provide a suitable residence time preferably of at least two minutes, and ' usually in the range of about 5 to 15 minutes.
The pressure in the settling zone or decanter should be sufficient to maintain both the extractant and the water in liquid phase, e.g. 1 to 200 atmospheres, depending r upon temperature. The temperature, in the decanter will be at or below that of the carbon-water dispersion leaving the scrubbing zone e.g. ambient - 700F., and preferably in the range of about 200-550F.
Clarified water is removed from the decanter, and s at least a portion in admixture with fresh water may be recycled to the scrubbing zone. Optionally, at least a por-tion of the dissolved water soluble constituents from the extractant may be removed from the clarified water by con-ventional means before the water is recycled to the scrubbing zone.
For example, the clarified water stream may be introduced into a gas-liquid separation zone where the pressure is suddenly dropped. A light gaseous fraction is , flashed off which is cooled below the dew point to separate uncondcnsed light gases, water, and water soluble liquid hydrocarbon compounds. Clarified water is removed from the separation zone and recycled to the scrubbing zone.
As previously mentioned, another embodiment of the invention involves two simultaneous additions of extractant in two stages. Thus in the first stage, the aforesaid carbon-water dispersion is resolved into a clarified water layer and a dry carbon powder which floats on the clarified water.
This may be accomplished by adding the liquid extrac~ant to the carbon-water dispersion in an amount just sufficient to render all of the carbon hydrophobic but insufficient to produce a carbon-extractant dispersion at this stage. As a result of this smaller amount extractant, the carbon separates rapidly and substantially completely from the water and floats to the surface of the clarified water layer as a dry -:
appearing unagglomerated soot.
The liquid extractant introduced into the mixing zone in the first stage comprises a portion of said light liquid fraction obtained subsequently in the distillation zone. However, the light liquid fraction may be mixed with 0 to 25 weiqht % of the thin centrifuge stream. Further, optionally supplemental liquid extractant make-up from an external source may be introduced into the mixing zone at this time.
The amount of liquid extractant to be added may be obtained experimentally by shake tests. Small increments of extractant are added to the carbon-water dispersion until the carbon separates rapidly and floats on the surface of the clarified water. Thus when the water phase is clear and the carbon is "dry" and fluffy, the amount of cxtractant is optimum. The amount of extractant added in the first stage is s 10'79973 about 1 to 3 times the Oil ~bsorption No. of the particulate carhon in the carbon-water dispersion. This may range between about l.S - 10 lbs. of extractant per lb. of carbon or more likely in the ran~e of about 1.5 to below 5.
In the second stage, the particulate carbon is floated off the surface of the clarified water layer by introducing a horizontal stream of liquid extractant co~-prising at least a portion of said thin centrifuge stream optionally in admixture with a portion of said li~ht liquid fraction from the distillation zone into said decanter at the interface between said clarified water layer and said particulate carbon. The sweeping action across the intcr-face will also disperse the carbon in the light liquid ~, fraction.
The principal advantage of the two-stage addition of the liquid extractant lies in the avoidance of the forma-tion of emulsions. In the first stage, the carbon-water dispersion is resolved and the carbon floats to the surface of the water witll the addition of a minimum of liquid ex-tractant. In the second stage the secondary extractant is added in much larger amounts with a minimum of mixing with ~- the water so that emulsion formation is avoided even if emulsifying agents are present.
The amount of liquid extractant that is introduced into the second stage is sufficient to form a carbon-extractant dispersion containinq about 0.5 - 5 wt.% carbon.
This amount may be about ten times the amount of extractallt that was used in the first stage. The clarified water is removed from the decanter in the manner described previously.
As previously mentioned, the carbon-extractant 1079~73 diSp~rsion re~oved ove.head from the decanter may he concerl-trated by centrifugal separation and divicled into a thick stream of carbon-extractant dispersion and a comparatively thin stream of carhon-extractant dispersion. The thick stream may have a carbon eontent in the range of ~bout 1 to 10 wt. ~ and suitably about 4 to 7 wt. %. The thin stream has a carbon content in the range of ahout 0.02 to 1.0 ~Jt.~, and suitahly about 0.1 to 0.5 wt. ~. The thiek stream of carbon-extraetant is then passed into the distillation column in admixture with fresh heavy liquid hydroearbon fuel as previously deseribed. This pumpable mixture may comprise about .02 to 40 and preferably 0.1 to 10 lbs. of fresh heavy liquid hydroearbon fuel per lb. of extraetant in the t~iek centrifuge stream.
Prior to recyele to the mixincJ and separating zone, the eomparatively thin eentrifuge stream of earbon-extraetant may be passed into a gas-liquid separator where any waste gas is removed.
The temperature and pressure in the deeanter and eentrifugal separation zone are preferably substantially the same.
~ pumpable dispersion of partieulate earbon in extraetant eontainincJ about 0.5 to 5 wt. ~ earbon, and preferably about 0.5 to 3 wt. % earbon is removed from the deeanter. ~bout .02 to 40 lbs. and preferably about .1 to 10 lbs. of a fresi- heavy liquid hydroearbon fuel may be mixed with eaeh lh. of extraetant in said earbon-extraetant dispersion.
The amount of fresh, heavy liquid hydroearbon fuel, as previously deseribed, is kept to a minimum. This amount should he suf~icient only to form a pumpable bottoms slurr~ ith the particulate carbon from said carbon-extractant dispersion in a subsequent fractional distilla-tion zone. The aforesaid pu~pa~le bottoms slurry may have a carhon content of about 0.5 to 25 wt. ~ and preferably 4 to 8 wt. ~.
Optionally, about 0 to 0.25 lbs. of make-up uid extractant may be introduced into the system ancl mixed with each lb. of carbon-extractant dispersion plus lo heavy liquid hydrocarbon fuel. The mixture of fluids is preferably preheated to a temperature in the range of about 2~0 to GOor. and introduced into a fractional distillation column. A light liquid extractant fraction having an atmos-pheJic boiling point in the range of about 100 to 700F., such as in the range of about 150 to 600F., is removed overhead from the distillation tower.
A suitable pressure in the distillation tower may be in the range of about 14.7 to 100 psig. Normally, con-ditions of temperature and pressure in said distillation column are such that substantially no fractionation of the fresh heavy liquid hydrocarbon fuel takes place. In such instance the overhead light fraction from the distillaticn - column substantially comprises either said light liquid hydrocarbon fuel or said mixture of liquid organic by-products from the oxo or oxyl process which then solely comprises said liquid organic extractant. I~owever, in other cmbodiments the distillation column may be operated so that the overhead fraction includes 0.1 to 25 weight ~ of light liquid hydrocarbon fuel and the remainder a mixture of ; 30 liquid organic by-products of oxo or oxyl process. The light ]iqui-l hy(lrocarbon fuel are liaui~l hydrocarbon fuels .

10799'73 having gravities of 20 ~PI and higher, for eY.ample butanes, pentanes, hexanes, benzol, toluol, natural gasolin~, gasoline, naphtha gas oil, their mixtures and the like.~lterna~l the light liquid fraction which is recycled to said mixing zone as said previously described liquid organic extractant may have the composition shown in Tables I and II.
The light liquid organic fraction is removed from the conventional fractional distillation column or stripping tower, cooled, liquefied, and recycled to said mixing zone, decanter, or both as said light liquid fraction extractant, as previously described.
The distillation or stripping tower is opcrated under suitable conditions for removing the carbon rom said thick centrifuge stream and producing said substantially carbon-free light liquid fraction extractant. There is also produced a pumpable residue slurry comprising said particu-late carbon and the unvaporized portions of said heavy liquid hydrocarbon fuel and said extractant. This residue slurry contains about 0.5 to 25 wt. % carbon and is removed from the bottom of the distillation column. It may be passed in ir.direct heat exchange with incoming feed, and then introduced into said partial oxidation synthesis gas generator as at least a portion of the feed. Fuel mixtur~s comprising about 1 to 99 wt %, and preferably about 5 to 50 wt. ~ of said mixture of liquid organic by-products from the oxo or oxyl process and the remainder said bottoms slurry from the distillation column are preferably intro-duced into the synthetic gas generator as feed. They may be introduced into the gas generator in liquid phase or vapor phase, and may be in admixture with ~2- Alternately, said fuel mixture may be hurned in a furnace, for example s ,~

1079~73 to pro(luce steam.
Although the process of the invention is particu-larly suitable for removing substantially all of the dispersed particulate carbon from a carbon-water dispersion produced by water scrubbing the effluent gaseous stream from the p~rtial oxidation process, it m~y be similarly used in many other hydrocarbon gasification processes.
DESCRIPTION OF TI~E DR~WIN~
AND EXAMPLES
A more complete understanding of the invention may be had by reference to the accompanying schematic drawing which shows in Figure I the previously described process in detail. Quantities have been assigned to the various streams on an hourly basis so that the following descrip-tion in Example I may also serve as an example o~ 'he sub~ect invention.
EXAMPLE I
In this embodiment of the continuous process, the decanter is operated in a single stage. Further, the ex-tractant used to resolve the carbon-water disp~rsion is a light liquid hydrocarbon fuel. Referring to Fig. I of the drawing, on an hourly basis about 14,400 lbs. of a particu-late carbon-water dispersion at a temperature of about 250F. and containing about 144 lbs. of particulate carbon from the gas scrubbing zone of a process for making synthesis gas by the partial oxidation of a hydrocarbonace-ous fuel to be further described are passed through line 1 into mixer valve 2 in which said carbon-water dispersion is mixed with about 10,727 lbs. of a light liquid hydrocarbon fuel cxtractant from line 3. The liquid extractant in line 3 comprise.s 2,880 lbs. of light hydrocarbon fuel fraction :

10799~73 from lin~s ~ and 5, which is ~)roduced subsequently in the process in fractional distillation column 6, to be furthe~
lescribed, in ad~ixture ~it~ 7,847 lbs. of a thin centri-fuge strea~ which is pumped by pump 7 from holcling tan~ 8 through lines 9 an~ 10. In the subject example the llght liquid hydrocarbon fuel is naphtha per ASTM D288. The thin centrifuge stream comprises a carbon dispersion of said light liquid hydrocarbon fuel extractant containing particulate carbon, to be further described.
The mixture of light liquid hydrocarbon fuel extractant and carbon-water is passed through line 14 into decanter 15. A relatively quiescent volume is provided in ¦ the settling zone at a pressure of about 25 atmospheres.
Substantially clear water, containing substantially no dissolved water soluble constituents from said light liquid hydrocarbon fuel fraction extractant, settles by gravity to the bottom of decanter 15 and is removed by way of line 16.
If necessary, the water in line 16 may be purified by conventional means and then recycled to the gas cooling and scrubbing zone. A portion may be discharged from the system and replaced with fresh water. 10,727 lbs. of said light liquid hydrocarbon fuel extractant in a dispersion of not less than 144 lbs. of particulate carbon together with any entrained water are xemoved near the top of decanter 15 by t . way of line 17 and are introduced into a disc-type centri-; fugal separator 18. The centrifuging speed corresponds to about 9500 revolutions per minute.
t About 7,847 lbs. of a thin centrifuge stream of said light liquid hydrocarbon fuel extractant containing particulate carbon is removed from centrifuge 1~ b~ way of line 19 and is introduc~d into holdillcJ tan~ 8. Waste ~as is discharged to a flare through lin~ 20. Optionally, light - 3~1 -1079~'7,3 liquid hydrocarbon fuel make-up from an external source mcly be fed into the system through line 21 valve 22 and line 23.
~bout 3024 lbs. of a thick centrifuge stream o~
i particulate carbon-extractant is removed from centrifuge 18 by way of line 24 containing about 144 lbs. of particu-late carbon. Thick centrifuge stream is mixed in line 25 with about 8,172 lbs. of a fresh heavy liquid hydrocarbon fuel feed from line 26. The heavy hydrocarbon fuel is a heavy fuel oil having the following characteristics:
API 1916, Gross Heating Value 17,814 BTU per lb., and Ultimate Analysis, Wt. ~ C 81.2, H, 11. 4, N 0. 5, S 3.3, f 0 3.5 and Ash 0.2. The mixture in line 25 is introduced into fractional distillation tower 6.
The operating conditions of distillation column 6 in this example are such that substantially none of the - heavy liquid hydrocarbon fuel in the mixture from line 25 l ~ is removed as a portion of the light hydrocarbon fraction F leaving the column by way of line 27. In other words ~ ' substantially all of said heavy liquid hydrocarbon fuel feed passes out of the bottom of column through line 28 as a pumpable carbon slurry containing 144 lbs. of particulate carbon. The pressure in the distillation column is about 15 psia.
The light liquid hydrocarbon fuel extractant in the thick centrifuge stream charged to distillation column 6 is vaporized, and 3,606 lbs. are passed overhead as a ~ , carbon-free stream through line 27. This stream is then cooled and condensed in heat exchanger 29. The stream is passed through line 30 into liquid-liquid separator 31.
-~ 30 Anv water is drawn off through line 32. The light liquid hydroctlrbon ~uel ext~actant i5 purped b~ means of pump 33 through line 34 and into line 35. About 2,880 lbs. of t~ie 10~9g~3 light llquld hy~rocarbon ~uel extractant 1~. passed thrjugh llnes 35, 4, 5, and 3 into mixing zone 2 as previously described as a portion of said single stage llquld extractant. The remalnder of the llquld stream lrom line 35 l.e. 726 lbs. ls recycled throueh llne 36 lnto rractionation column 6. The recycle ratio for dlstillation column 6 may range from 0.05 to 0.5 lbs. of reflux i~ llne 36 per lb. of extractant ln the column - feed in llne 25.
- 10 A sllp strcam ls removed from column 6 by way ~r llne 40 and passed through reboiler 41 where the temperature is raised to the deslred temperature for vaporizing the overhead ~ractlon and recycled t~ column 6 through line 42.
me b~ttoms carbon-oll slurry in line 28 compri-slng 8,172 lbs. ~r heavy liquld hydrocarbon ruel oil and 144 lbs. of partlculate carbon are pumped by means of pump 43 into the reaction zone of a synthesls gas generator (not shown~ as a portion of the ruel. Thus the bottoms slurry may be pumped through llne 44-46, valve 47, and 2~
llne 4e lnto a synthesis gas generator (not ~hown).
Advantageously, a portlon of the fresh mlxture r llquld organic by-products from an oxo or oxyl process ln line 53, to be rurther described, is passed through valve 54, line 55 and lnto line 45 where lt ls mlxed wlth sald carbon-oll slurry ~rom llne 44. Thls lmproved llquld fuel mixture ls then passed through lines 46 and 4~ lnto sald synthe~ls gas generator as at least a portlon Or the feed. Optlonally, a portlon of the mlxture of ~lulds ln line 45 may be lntroduced lnto a furnace (not shown) as ~ 1~)79973 ru~l, bv w~ of line 56, valve 57, and line 58.
Thus, in the subject process a~out 1,794 lbs.
of liquid organic by-products from an oxo-process for the production of n-butyraldehyde from line 53 are mixed in line 45 with 8,316 lbs. of carbon-heavy fuel oil slurry from line 44. This mixture is then introduced into the synthesis gas generator as said hydrocarbonaceous fuel ancl reacted with 10,183 lbs. of oxygen (99.5 mole % 2) and 4,395 lbs. of steam.
~- 10 About 497,000 standard cubic feet (dry basis) of synthesis gas is produced in a noncatalytic free-f low gas ~; generator at a temperature of about 2400F. and a pressure of about 37 atmospheres by the partial oxidation of said hydrocarbonaceous fuel feedstock. The composition of the ,~ synthesis gas in mole ~ follows: CO 41.00, H2 42.22, C2 4-39~ H2O 11.26, CH4 0.21, ~ O.ll, N2 0.12, H2S 0.66, and COS 0.03. ~fter purification, as previously described, the mixture of H2 and CO is compressed and introduced into said oxo process for the production of n-butyraldehyde.
~ 20 EX~PLE II
'~ In this embodiment of the invention the liquid organic extractant comprises a mixture of liquid organic by-products from an oxo or oxyl process. Further, the liquid organic extractant is introduced in one stage. The compo-sition of the liquid organic extractant is shown in Table III
and the Ultimate Analyses is shown in Table IV with sub-, stantiaily all of the water-soluble compounds removed. The synthesis gas produced has the following composition in mole ~ : CO 41.00, H2 42.22, CO2 4.39, H2O 11.26, CH4 0.21, A O.ll, ~2 0.12, H2S 0.66 and COS 0.03. After purification as previously descxibed to remove acid gases ancl particulate .

~ - 37 -1079~73 car}~on, the synthesis gas is compressed and introduced into an oxo process (not shown), for example, to produce n-butyraldehyde by the hydroformylation of propylene in the presence of cobalt catalyst at a temperature in the range of about 130-175C. and a pressure of about 200 atmospheres.
With reference to Fig. 2 of the drawing, on an hourly basis about 14,400 lbs. of a particulate carbon-water dispersion at a temperature of about 250F. and con-taining about 144 lbs. of particulate carbon from the previously described gas scrubbing zone of the process for making synthesis gas by the partial oxidation of a hydrocar-; bonaceous fuel as described in Example I are passed through line 1 into mixer valve 2 where it is mixed with 10,727 lbs.
of said liquid organic extractant from line 5. With valves 3 and 70 closed and 71 and 4 open said liquid organic extractant in line 5 comprises 7847 lbs. of thin centri-fuge stream from holding tank 72, line 73, pump 74, and lines 75-78 in admixture with 2,880 lbs. of the light overhead fraction from distillation column 21 comprising a mixture of liquid organic by-products from said oxo process which is supplied via lines 38, 39, and 78.
The mixture of extractant and carbon-water is passed through line 6 into a phase separating zone i.e.
decanter 7. ~ relatively quiescent volume is provided in the settling zone at a pressure of about 25 atmospheres.
Substantially clear water containing any dissolved water-soluble constituents of said liquid organic extractant settles by gravity to the bottom decanter 7 and is removed by way of line 8. Preferably, the water in line 7 may be purified by conventional means to remove any dissolved water-soluble constituents from the extractant, and then 1079~73 recycle(l to tlle synthesis gas cooling and scrubbing zone.
portion of this water may be discharged from the system and r~placed by fresh water. ~y this means 10,727 lbs. of extractant containing at least 144 pounds of soot may be removed from the decanter through line 9. This stream is charged into a conventional centrifuge 80. The centrifuging speed corresponds to about 9500 revolutions per minute.
About 7817 lbs. of said liquid organic extractant in the thin centrifuge stream are removed from centrifuge 80 by way of line 81 and are introduced into holding tank ; 72. Waste gas is discharged from the system through line 82 to flare. The dispersion of particulate carbon and extractant is removed through line 73 and pumped by pump 74 into mixer 2 as a portion of said liquid organic extractant, as previously described.
!
A thick centrifuge slurry stream comprising about 144 lbs. of particulate carbon and about 288Q lbs.
of said liquid organic extractant is removed from centrifuge 80 by way of line 85. This slurry stream may be mixed in line 86 with fresh mixture of liquid organic by-products of said oxo process as previously described, which is intro-duced into the system by way of lines 15, 87, valvé 88, and line 89. This mixture is then mixed in line 19 with 8172 lbs. of fresh liquid hydrocarbon fuel feedstock e.g.
heavy fuel oil as previously described, which is intro-duced into the system through line 20, and then passed into distillation zone 21.
- The operating conditions of distillation column 21 in this example are such that substantially none of the heavy liquid hydrocarbon fuel feed from line 20 that is charged to the column as a portion of the feed is removed i . as a portion of the overhead light fraction. Thus sub-stantia]ly all of said heavy liquid hydrocarbon fuel passes out ~f the bottom of column 21 as a pumpable carbon slurry through line 44 containing 144 lbs. of carbon and j substantially no unvaporized residue from said mixture of liquid organic by-products of the oxo process. The pressure in the distillation column is about one atmosphere.
About 3606 lbs. of liquid organic extractant in distillation column 21 are vaporized and passed overhead as a carbon-free vapor stream through line 22. This stream is then cooled and condensed in heat exchanger 23 and passed through line 24 into liquid-liquid separator 25.
~ ~ny water may be drawn off through line 34 and the liquid i orqanic extractant is pumped by means of pump 36 into line37. About 2880 lbs. of the liquid organic extractant is passed through lines 38, 39, 78, and 5 into mixing zone 2 ', as previously described. The remainder of the liquid stream from line 37 is recycled through line 40 into fractionation column 21. Recycle ratio for distillation column 21 may range for example from 0.05 to 0.5 parts by weight of reflux per part by weight of column feed.
A slip stream is removed from column 21 by way of line 41 and passed through reboiler 42 where the temperature is raised to the desired temperature for vaporizing the overhead fraction, and then recycled to column 21 through line 43.
~ About 8316 lbs. of the bottoms carbon-oil slurryj in linc 44 containing about 144 lbs. of carbon, may be pumped by means of pump 45 into the reaction zone of said synthesis gas generator as at least a portion of the feed.

107997~

Optionally, a portion of the mixture of fluids in line 47 may be introduced into a furnace (not shown) as fuel, l~y way of line 54, valve 55, and line 56.
EX~MPLE III
In this embodiment of the invention, decanter 7 is operated in two-stag2s to improve performance. Aside from this change, the rest of the process is substantially the same as that déscribed previously in Example II.
With reference to Fi~ure 2 of the drawing on an hourly basis, in the first stage of the two-stage decanter operation with valve 71 closed and valves 4, 70 and 3 open about 432 lbs. of the mixture of carbon-free liquid organic by-products from said oxo process obtained as a portion of the overhead fraction from distillation column 21, are introduced into mixer 2 by way of lines 38, 39, 78 and 5 along with 14,400 lbs. carbon water dispersion containing 144 lbs. of particulate carbon from line 1. This amount of liquid extractant is sufficient to render the particulate carbon hydrophobic and to release substantially dry powdered carbon. In the second stage of the continuous decanter operation, simultaneously about 10,295 lbs. of a carbon-extractant dispersion from line 60 are introduced into the decanter near the carbon water interface to float off the carbon particles and to form the carbon-liquid organic extractant dispersion which is withdrawn through line 9.
The liquid extractant in line 60 comprises 2880 lbs. of said mixture of liquid organic by-products from said oxo process obtained from distillation column 21 via lines 38, 90, valve 70, lines 91-92 and valve 3, and about 7847 lbs. of the thin centrifuge stream which contains carbon from line 10'79~73 73, pump 74, lines 75, 92 and valve 3. Optionally, either the thin centrifuge stream 75 or the light liquid fraction in line 38 from distillation column 2, with or without ad-mixture with the other stream may be introduced into the first stage, the second stage, or both as at least a portion of said liquid organic extractant.
Obviously, various modification of the invention as herein set forth may be made without departing from the spirit and scope thereof and therefore, only such limita-tions should be made as are indicated in the appended claims.

~;

,................................................................... .

Claims (15)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for producing gaseous mixtures comprising H2 and CO comprising:
(1) reacting by partial oxidation a hydro-carbonaceous fuel with a free oxygen-containing gas in the reaction zone of a free-flow noncatalytic synthesis gas generator at a temperature in the range of about 1300 to 3500°F. and a pressure in the range of about 1 to 300 atmospheres in the presence of a temperature moderator to produce an effluent gas stream comprising H2, CO, CO2, H2O, entrained particulate carbon, and at least one member of the group H2S, COS, CH4, N2, and A;
(2) introducing said effluent gas stream into gas-cooling and gas-scrubbing zones in which the gas stream is cooled and contacted with water, effecting the removal of said particulate carbon from said effluent gas stream and producing a carbon-water dispersion;
(3) removing gaseous impurities from the gas stream leaving (2) producing a product gas stream comprising H2 and CO;
(4) contacting said carbon-water dispersion in a mixing zone with liquid organic extractant from the group consisting of a light liquid fraction obtained from the distillation zone in (6), a thin centrifuge stream of carbon-extractant obtained from the centrifugal separating zone in (5), and mixtures thereof; wherein the amount of said liquid organic extractant added to said carbon-water dispersion is sufficient to render all of the carbon particles in said carbon-water dispersion hydrophobic and to resolve said carbon-water dispersion, and removing a stream of clarified water and a separate stream of carbon-extractant dispersion containing about 0.5 to 5 weight percent carbon in a separating zone at a tempera-ture in the range of about ambient to 700°F. and a sufficient pressure to maintain said liquid organic extractant and said clarified water in liquid phase, say in the range of about 1 to 200 atmospheres depending upon temperature;

(5) introducing said carbon-extractant dispersion from (4) into a centrifuging zone at a temperature in the range of about ambient to 700°F. and a pressure in the range of about 1 to 200 atmospheres, separately withdrawing from said centrifuging zone a thick centrifuge stream of carbon-extractant dispersion having a carbon content in the range of about 1 to 10 weight percent, and a thin centrifuge stream of carbon-extractant dispersion having a carbon content in the range of about 0.05 to 1.0 weight percent;
degasifying said thin centrifuge stream if necessary; with-drawing a partially clarified water stream from said separating zone, and recycling said water to said gas-scrubbing zone in (2) to scrub carbon from the effluent gas stream from the gas generator; introducing said thick stream of carbon-extractant dispersion in admixture with fresh heavy liquid hydrocarbon fuel into a fractional distillation zone; and (6) removing a light liquid fraction from said distillation zone and introducing either said light liquid fraction or said thin centrifuge stream from (5), or both of said streams into said mixing zone in (4) as previously described as said light liquid extractant; and removing from said distillation zone a pumpable bottoms carbon slurry and introducing same into said gas generator at at least a portion of said fuel.

2. The process of Claim 1 wherein all of said liquid organic extractant is introduced into the mixing zone in step (4) in a single stage and comprises a mixture of said light liquid fraction from the distillation zone and said thin centrifuge stream in the amount of about 0.05 to 20 parts by weight of said light liquid fraction from the distillation zone for each part by weight of said thin centrifuge stream.

3. The process of Claim 1 where in step (4), said liquid organic extractant in an amount of about 10 to 200 times the weight of the particulate carbon in the carbon-water dispersion is mixed with said carbon-water dispersion.

4. The process of Claim 1 wherein the contacting of said carbon-water dispersion in step (4) is effected in two stages including in the first stage the step of mixing said carbon-water dispersion in a mixing zone with a sufficient amount of liquid organic extractant so as to render all of said particulate carbon hydrophobic and to release dry powdered carbon from said carbon-water dispersion, with said carbon floating on the surface of a clarified layer of water in said separating zone; and in the second stage introducing a stream of liquid organic extractant into said separating zone adjacent the water surface to float off said carbon from the surface of the bottom layer of said clarified water while forming said carbon-extractant dispersion containing about 0.5 to 5 weight percent carbon.

5. The process of Claim 4 wherein the amount of said liquid organic extractant mixed with the carbon-water dispersion in the first stage on a weight basis is about 1 to 3 times the Oil Absorption Number of the particulate carbon as determined by ASTM D281-31.

6. The process of Claim 4 wherein the liquid organic extractant in the first stage comprises said light liquid fraction from the distillation zone in admixture with about 0 to 25 weight % of said thin centrifuge stream, and the liquid organic extractant in the second stage comprises at least a portion of said thin centrifuge stream, optionally in admixture with a portion of said light liquid fraction from said distillation zone.

7. The process of Claim 6 wherein the total amount of liquid organic extractant introduced comprises about 0.05 to 20 parts by weight of light liquid fraction from the dis-tillation zone per part by weight of said thin centrifuge stream.

8. The process of Claim 1 provided with the additional step of mixing a portion of a fresh mixture of liquid organic by-products from the oxo or oxyl process with the pumpable bottoms slurry leaving step (6), to produce a gas generator feedstock or a furnace fuel or both.

9. The process of Claim 1 provided with the additional steps of expanding and dropping the pressure of the clarified water from step (1), and in a gas-liquid separation zone flashing off a light gaseous fraction;
removing a clear substantially water stream from said gas-liquid separation zone and introducing said clear sub-stantially water stream to said gas-scrubbing zone to scrub the effluent gas stream from the gas generator; cooling said light gaseous fraction and separating therefrom uncondensed light gases, water, and partially water soluble liquid hydro-carbon compounds.

10. The process of Claim 1 provided with the step of mixing supplemental light liquid extractant make-up with the liquid organic extractant in step (4).

11. The process of Claim 1 wherein said liquid organic extractant is a light liquid hydrocarbon fuel with an atmospheric boiling point in the range of about 100 to 500°F., degrees API in the range of over 20 to 100, and a carbon number in the range of about 5 to 16.

12. The process of Claim 1 wherein said liquid organic extractant is a mixture of liquid organic by-products from an oxo or oxyl process.

13. The process of Claim 1 wherein said heavy liquid hydrocarbon fuel in step (5) has a gravity in degrees API in the range of ab out -20 to 20.

14. The process of Claim 1 wherein said hydro-carbonaceous fuel is selected from the group consisting of various petroleum distillates and residue, whole crude, fuel oil, reduced crude; coal tar oil; shale oil; tar sand oil and mixtures thereof; pumpable slurries of solid carbonaceous fuels, such as lignite, bituminous and anthracite coals, in water or liquid hydrocarbon fuels;
pumpable slurries of carbon soot in liquid hydrocarbon fuel or residues thereof and mixtures of organic by-products from an oxo or oxyl process or residues thereof; and mixtures thereof.

15. The process of Claim 1 provided with the additional steps of introducing the product gas from step (3) into an oxo or oxyl process for the catalytic produc-tion of aldehydes or alcohols and separating therefrom a mixture of liquid organic by-products; and wherein a portion of said liquid organic by-products is used in step (4) as said liquid organic extractant.