Process Of Production Cs2.pdf 4s5v1q

Jan. 19, 1954

2,666,690

|-|_ o. FOLKINS ErAL PRocEss FOR THE PRODUCTION 0F CARBON DxsuLFIDE

Filed DeCS.y 28, 1951

2 Sheets-Sheet 1

Jan. 19, 1954

H. o. FoLKlNs ETAL

2,666,690

PROCESS FoR THE PRODUCTION oF CARBON DISULFIDE ` Filed nec. 28, 1951

ì

2 sheets-sheet 2

_ wwî | tl

2,666,696

Patented Jan. 19, 1954

f UNITED » STATES PATENT] OFFICE . ' ' PnooEssFoR THE PRODUCTION oF

v

CARBON DISULFIDE

Hillis 0. Folkins and Elmer Miller, Crystal Lake, and Harvey Hennig, Cary, Ill., assignors to Food Machinery and Chemical Corporation, New York, N. Y., a- corporation of Delaware.

ApplicationvDecember 28, 195.1, Serial No. .263,72418 Claims. 1

(Cl. 23-206)

.

The present invention is directed to a process

for converting hydrocarbons to carbon disulfide yby reaction with sulfurv wherein a scavenging or agglomerating material is utilized to nulliiy the

deleterious eiîect of side reaction products. It is known to prepare carbon disulfide by reaction of sulfur with various hydrocarbons un der catalytic 'conditions 'at elevated ìtempera tures and pressures. It is reported that hydro carbons having one to three carbon atoms in the molecule 'are preferred for the reaction for economic reasons, although certain investigators show that unsaturated hydrocarbons and higher molecular weightr hydrocarbons may be satis factorily used in the process.

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reaction under conditions that are kinetically optimum for each hydrocarbon gas. For exam ple, in some instances the space velocities of the reactants through the reaction zone must be ad justed downward from optimum space velocities suitable for the particular reaction environment of hydrocarbon gas and operating conditions used, in order to obtain maximum yields per from the reactants. The alternates to lower space velocities are to increase temperature and hence corrosion diiiiculties or to operate' under high pressures. Generally, the use of higher space velocities lowers the extent of conversion. Too low a conversion level will interfere with

Because oi the 15 product separation and recovery. By operating

complexity-of the reaction when using higher molecular weight hydrocarbon charge gases wherein there are produced various side reaction products, it is generally preferable to use meth Iane or a gas comprising highV percentages of

methane for the reaction. Experiments have in .dicated that _hydrocarbons containing two to Iive carbon atoms in the molecule are prone to

yield deleterious side reaction products which contaminate the carbon disulfide product; cause severe catalyst decline and consequent vdrop in conversion, and contaminate the recycle sulfur, making its recovery for reuse more difiicult. -T-he ynatural gases containing 4 mole per cent ofrCs hydrocarbons and 1 mole per cent or more of C4 '

hydrocarbons have been designated as border line charge gases for the carbon disulfide reac tion since even these small amounts of- hydro

under conditions of lower space velocities, higher conversions to carbon disulfide may be main tained, but the process is more inefficient and productivity may be lower. Naturally, the use of excessive amounts of sulfur complicates the

product purification steps and sulfur recovery. The present process eliminates the above prob lems without sacrifice of any of thev advantages gained from the use of theabove mentioned techniques, and is based on the discovery that

by removing the deleterious side reaction prod ucts as they are formed by use of an agglomerat

ing materialpresent during the reaction, their eii‘ect upon the reaction is minimized and the sulfur content thereof is made recoverable. Re

moval of the side reaction products allows oper ation at. all times. under optimum reaction con ditions for maximum yield per without com

carbons of higher molecular weight than methane

plicating product recovery or sulfur recycle.` ÁThis

tamination and plugging of the reaction zone

type wherethedeleterious effects of the sulfur

have beenrfound to cause Vsevere catalyst con- .-. - is extremely advantageous in a reaction of this with tars and polymers.

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containing sidereaction productsfincrease with

increasing the eiïiciency of the reaction and the

time and the presence ,of even a small amount in the reaction zone is very detrimental.

ease -' of product recovery. These include new catalysts, use of an excess of _sulfur over the

invention to provide a process for producing

p lNumerousl techniques have been developed for

stoichiometric

requirements,

preheating

the

’ charge gas and' sulfur to reaction temperature

Accordingly, it is the primary object of this carbon disulñde by reaction of hydrocarbons with sulfur under conditions of maximum convert

sion, with a minimum of influence from side orabove, and techniques for separating the car-_ bon disulfide from the` excess sulfur and side 45 reaction products and with little or no diiiiculty in product recovery or sulfur recycle. reaction products. These improved techniques A secondary object of` this invention is to‘ pro have greatly increased the amount of carbon di vide a .process for the eiiicient> and economic sulfide which ¿can bev obtained from a given production of‘ carbon -disulfide from hydrocar amount Yof charge gas;UA However, in their prac tice it is not always i possible to conduct the 5 bons that are prone to form vdeleterious sulfur

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containing side reaction products wherein an

agglomerating material, which may be catalytic or not, acts to remove these deleterious side re

action products from with the reactants before there has been an opportunity for them to lower the reaction emciency.

Another object of this invention is to take

4 In coil 22 of heater t, the molten sulfur is heated to a sufficiently high temperature to vap orize it, as for example, 850° to 12%o F’. under given operating pressures. Preheated charge gas leaves coil S by line 24, controlled by valve 25, and es to line 225 Where it s and ñuidizes the

agglomerating or catalytic material before enter advantage of the unreacted sulfur content and ing reactor 3E). Sulfur vapors proceed from coil the combined sulfur content within the effluent 22 via line 32, controlled by valve 34, to the products, removed by the agglomerating material, charge gas before it enters line 28. Simultaneous to react 'with îaîprincipal byeproduct, hydrogen intro'duction‘e‘f y‘the reactants finto . with sulfide, .from `the reaction, thus 'reforming in "each other ¿and "into with the agglomer usable condition sulfur which would .otherwise ating material bei-ore their entrance into the re be lost. -í'actor is generally the preferred technique. How Still another object of this inventionis topro -even ins-ome cases, especially where higher hy vide a process for producing carbon `disulfide -idrocarbons are being used as the charge stock, it wherein an agglomerating material removes the maybe preferable to introduce the sulfur vapor tars, polymers, some of the excesssulfur, anilsul y'.to'f.thei’reac'tor separately. In this case, the sulfur fur-carbon complexes for exid‘ationito substan- ` «vapors 41Vfrom line 32 to line St, controlled by tial amounts of sulfur dioxide, Whiehîis'utilized" 20 ~valveì38,.into‘reactor 3&3 where they meet the hy to react with. the hydrogen sulñd'e'byeproductito 'drocarbonggas and "fluidized material. Both the form elemental sulfur for reinrthe ...reaction 4icuteheatecl rchar-.ge :gas and the vapor-ized sulfur Further objects and advantages of the inven may be subjected to superheating to reaction tem tion will become apparent as the description peratures or above prior to their entry into re. thereof proceeds. " actor 30. ‘The term “principal’products” fas =used'herein 'Reactor 3B >is provided‘mvith a bottom conical applies‘to the carbon disuli’ide and‘hydrogen ‘sul-' shaped section it!) yiri‘vvhich ‘the Ya'dmixture.sofipre fide which are `the normal Yproducts Aoí’ thevco'rr. heated sulfur vapors vand:chargefgas takes'place. plete reaction rof sulfur >and -charge gas. "The A vertical return .sta'ndpipe'ëiz lprovided with-.valve term “sidereaction.products”'wil1lbe used‘to refer 30 44 for ‘controlling the flow of iluidized :mixture to Vthe Aproducts ‘formed ’from Vthe~'incomplete sul therein is located vwithin Lthe ‘central‘portion of fur oxidation >of fthe carbon “and‘hydrogen-con reactor '30. Standpipe »i 2 extends `from îlower tent of the charge -gas. ’These "include carbon» conical section F493 yto upper enlarged conical sec

'hydrogen-sulfur complexes, 'sulfur-’carbon com plexes, tars, »and coke 'above referred to.

.

tion 46.

“Make-up” »agglomerating 'material is

' introduced’into'thesystem iromïhopper ‘fìâgcou

In the accompanyingïdrawingsjFigure"l shows 'one'type‘of‘reactor for producing carbon disulñde and a -system for loxidizing' theïhydrogen sulii'de to elemental sulfur. `lî'iefure'Zshovvs a'system'for separating carbon disul?lde‘fromhydrogen sulfide ‘ and other’sid e reaction products.

The present-process lis best described "byre’fer ence vtothe accompanying drawings. In Figure ~1 the charge gas is 'introduced'at vline v¿,fcontrolled

by valve fdfinto coil S of'heatertßavhereiit ispre heated >to reaction "temperature `or above. Ele mental suliur is introducedïrom‘sulfur hopper I0

into sulfur melter ÍZ’Where itis melted‘lby steam `in coil lll. »Heat is applied’t‘o coil ift-‘so that the

`moltensu'lfur is ‘kept at a‘temperature »between approximately 250° 'fand 300° F. and preferably about ’270° Obviously, those temperatures lare to be avoided at which~viscoussulfurforms. The 4molten sulfur is pumped from the melter Vi2 by

trolled‘by valve 5.5,into line T23 ‘which‘ïf'eeds *di rectly into'lower conical'secti'on ‘13D >oi’ reactorßll ' via line 52, controlled"by1valve`54~ ‘fUnderfeertain

conditions, itV mayïbe desirable to vutilize'tlfle latent heat content of the regenerated agglomerating material to aid in the lvaporization and 'super heating ofthe sulfur; "forthis purpose, the'fhvdro carbon chargegasheated orunhe'ate'd, es via lines 24 or 56 into line 28 Whereï'iluidiza'tion o'f the

agglomerating material-takes place. The iiuid~ ized mixture es 'from line 28 fv'ia fline "58 'and valve 60 to `jo'infthe»sulfur stream at a point in coil >22 ‘where :the 'temperature 'iis 'about Athe boil

ing point 'of sulfur. ‘The heated lmixture leaves . Acoil 22 and enters‘reactor 30 `via lines “32 fand F35.

' of the -agglorneratingfmaterial »with the reactants takes place in'reactor Si@ in the same manner as is employedin'the'moving bed, >pebio'le and v'llhermo‘for cracking processes, ‘Standpip’e means of sub-merged centrifugalpump VT5, lsuit- ‘ " 42 serves'to vcontrol the'llow of heavier-particles `able for‘handling molten'sulfun’through'lines f'l'ß -through the iiuidized mass. Conical section »'46 is `and 2U into coil 22 Aoi" heater 8. lSufficient pres designed 'so that the maximum‘hindered settling sure must 'be used >to force the Vmolten, sulfur takes place therein. 'through coil 22. ’For this Upurpose, pressures "up Accordingly, reaction vproducts and Athe ‘fine ‘to 100 pounds per square-inch-ma-y be used. The portion or smallerparticles of ,agglomeratingfma ypressures 4under 'which the >molten sulfuris moved terial rise to the-small upper >section 62S§for pas throughout the system will Idepend `upon `'the 'op sage into .cyclone separator 264.. `Cyclone .separa eration pressuremaintainedin the reactor, Tur tor 6.4 .serves to .separate .the line particles -of naces, and converters. That portion of the equipment Whichis > in 'con

agglomerating material ìrom the reactionprod

-‘tact -With sulfur-bearingvapors at elevatecl"‘tern-

ucts and return them into zthe denser-phase .of

vperatures >is `’cest constructed vof - a >materialwhich

the reaction. Reaction products leave the'top vof

-is 'resistant "to the corrosive -action lof sulfur. Various ¿stainless 'steel alloys, »such as those -ofl

>nde-hydrogen sulñdefseparation vsystem yto .be kde

reactor 3G vialine‘ûii to ) 4:to the carbon disul

high `chromium content, Vand 4cliromiuzneniclcel 70 scribed in Figure 5.2. The vreaction products may stainless steels stabilized ywith molybdenum, etc. contain considerable amounts 4ofi‘ñnesulfur par .have proved eiïective. Other -materials 'of con .struction include :aluminum coated steels, ire

.Iractory linings, -‘and .other .types of :stainless steels.

l

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ticles -and isome na’ggloinera‘ting material. This A-inay be removed .(in apparatus notshown) by

subjecting the product :stream Vto .c‘ountercurrent ß 'with cold :Waterfollowed by 'mechanical

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erator E3 may be an ordinary furnace type re# generator for oxidizing theI agglomerating mate

rialtoïiree it 'fromocclude'd tars, polymersrand sulfur-containing productsf The principalfprod ucts of this oxidation'willb'e sulfur dioxide, car bon dioxide, carbon monoxide, and water. yRe generator 68, as shownin Figure l, is a fluid type ' regenerator whereinvthe- oxidizing gas isY intro

a suitable area I I0. Within the tower the

duced at line 1d. Burning .of vthe agglomerating ' material takes place throughout the central por tion of regenerator 68, andthe regenerated ma terial is caught in the annular space defined >by inner cylinder ‘I6 and the outer wall of the. re-`A generator for return via! lines 'I8 and 28 `to the

reactor 30. The cycle of agglomeratingmaterial

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tions within converter 84 are from 500° to 750° F. The reaction may be caused to take place in one or more stages. For example, the first stage may be maintained at about 750° F. vand the second stage at about 500° F. If necessary, heat maybe applied to the reactor in order to initiate the re action. The conditions Within converter 84 are subject to some variation as long as the completeoxidation of the sulfur takes place. vEffluent gaseous products from the converter are itted at the bottom of sulfurv wash tower |04 by means of line I 05. Sulfur wash tower |04 is provided with a mistseparating section |08 and

separation of the sulfur and agglomerating mai terial, which is returned to regenerator 68. Heavier particles of agglomerating material leave the reactor 30 »by line 10, controlled by valve 12, to enter the bottom of regenerator 08. 'Regen

gases are subjected to countercurrent with a stream of molten sulfur conveyed from

sulfur melter I2 vialines I8, H2, and II4 through spray I I6. Molten sulfur accumulates inthe bottom of sulfur wash tower and any heat ab ' » sorbed from the hot gases or from the con

from- the reactor into the ’regenerator and back into the reactor is continuous and conditions are

densation'of the sulfur vapor is removed byj in direct heat exchange through cooling coil II8.

maintained for complete ~fluidization throughout

t Pump |20 serves to recycle molten sulfur to spray

the system.

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y

' Gaseous oxidation'products' from- regenerator

I I6 when sufiicient sulfur has accumulated in the bottom of tower I 04. When the process has

reached this point, the recycling of sulfur through 68 through line 80', controlled by valve’ 82, to line II 2 may be discontinued. Excess sulfur is catalytic converter 84 for the next step in the withdrawn through line |22 and ed to >`flash operation comprising the recovery of sulfur there ~ drum |24. Flash drum |24 eliminates the'occu from. On 'a molar'basis, for each mole of hy drocarbon gas reacting with four moles of sulfur, Í pational hazard in sulfur melter I2 due to ab sorbed hydrogen sulfide by flashing it off at at there are produced one mole of carbon disulfide mospheric pressure. f The sulfur within flash anl two moles of hydrogen sulfide. One mole of drum |24 is returned to sulfur melter I2 by line sulfur dioxide will be required to convert the two |25. i moles of hydrogen sulfide to‘free sulfur. Since Referring now to Figure 2, the carbon di from the carbon disulfide reaction there will be sulfide separation system, reaction products produced in the form of tars and polymers’ ad enter through line 280 into the lower portion of -mixed with unreactedlsulfur, an amount up to absorber 202. The absorber is fitted with about 0.5 mole of sulfur, in combined and uncom-l Raschig rings or other liquid-gas ing ele bined form, which will yield an equivalent num ments. Absorber 282 is preferably maintained ber of moles of sulfur dioxide in the regenerator, at a pressure of approximately 20 to 50 pounds there will ybe an excessof hydrogen sulfide to be per square inch gauge in orderyto absorb carbon oxidized by the sulfur dioxide. Consequently, a disulfide from the reaction product gases. >Lean portion of the hydrogen sulfide ranging from one oil is pumped into the top ofV the absorber from tenth to one-third is oxidized to form addi accumulator 204 through line 208 by means of tional sulfur dioxide Vforthe reaction.î For. this pump 2id. As absorber oil, heptane, or petro purpose, hydrogen sulfide from the separation leum naphtha having a boiling range of about system (described in Figure 2) is conducted 250° to 400° F. or other fraction boiling above through line 88, controlled: by valve. 88, toY fure the boiling point of carbon disulfide may be used. nace 90 wherein it is` oxidized ‘to sulfur' diox ide. The reaction taking place in furnace 90 is i

exothermic, and advantage is taken offthisto preheat the incoming hydrogen sulñde and air within the furnace itself. Furnace 90 may be packed with high temperature fire brick. Pre heating the entire furnace by burning natural gas therein may be necessary in; order to bring it

to operating temperature before the reactants -are introduced. By- lineï92 is Vprovided to con-. duct the balance of hydrogen sulfide .to the cata ` lytic converter 84.

The mixture of sulfur diox -60

ide and water formed in furnace 00 is conveyed by line 94 to waste heat boiler 85 wherein they are cooled before age to catalytic converter 84 by line 98, controlled by valve |08.

`

Other -solvents or absorbing mediums such as benzene and o-dichlorobenzene may be used. It is preferable to choose an absorber oil which

has a boiling point or boiling range not too far 'above the boiling point of carbon disulfide in order to enable the latter to be readily stripped therefrom. However, heavier absorption oils may be used and stripping carried out with the aid of a stripping medium suchv as- steam, methane,- or other inert gas. The unabsorbed gasleaves the top of the absorber through line 2|2 and es to furnace 98 and catalytic cone verter 84 of Figure l. This gas is composed of hydrogen sulfide with a small amount of hydro carbon gas and about 0.5 per cent'or less of car

bon disulfide. The rich oil is withdrawn from the bottom of absorber 202 by means of pump 2I4, ed through steam heater 256 where the from theregenerator 68 and furnace 90A with rich oil is preheated to a suitable temperature, as, the balance of hydrogen sulñde to form elemental for example, 208° to 350° F., and charged to the sulfur. This is accomplished by means of cata lytic converter -84 where in the reactant gases Ti) middle section of stripper 2i8. Stripper 2I8 is provided with Raschig rings 22d or other liquid downward through catalyst bed |02. The gasV elements. Carbon disulfide is catalystfor this purpose may be coarse Porof4

kThe final step in the sulfur recovery comprises complete reaction of the sulfur Ydioxide content

cel», a-highfiron activated bauxite which is-sup'. ported onv a stainless steel screen r'estingon ~al

strippedfrom the absorber oil and ed- from> the top of the stripper through linef222, water

cast; iron grate..y Normally vthe ,operating condie' '

cooler 'or condenser224, where the temperature

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7 is reduced ‘to 31019112- 'or less, to accumulator »22.6. f'gas »and/'or Ívapor which vremains "uncon

'densed sleeves, the. accumulator '225 through vline

carrying foutfthe invention, attention is now fdi rected to the reactants, ‘thefgeneral reaction con

ditions, :and .the techniques employed in both the

thermal andcatalytic aspects Yof lthe invention, in 223 yand is returned ’to ‘the .inlet of the fahsorber 232 'through line v221B. The stripper 2 i3 prefer -5 addition to pointing-‘out `speoiiic 'examples :of the ably 'operated at a pressure slightly above the

DI‘OCBSS.

:pressure in 4the yabsorber .262, as, for example, 25 -to 55 pounds per square inch gauge', .in order to

The chargegas of theipresent process will `com prise .anymixture- of hydrocarbons which vcon

,

avoid the necessity :of compressing the Y.gas re

tain :small amounts, that is, borderline amounts,

turned ythrough -line 228.

of constituents

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i

which fare _prone

to .form

.'I‘fhe vabsorber -oil is Withdrawn .from `the >plate deleterious side reaction products, to larger 230 in 4.the bottomrportion of stripper 2i 8 through amountsV of these. constituents. A typical hydro carbon comprises ya lnatural gas containing in line i232 vand lcharged Ato reboiler v234 and thence returned throughline 235 to the section of the excess of -¿one mo1e,;per cent of C4 and higher ' stripper below the plate 230. Plate 239 .is pro 15 molecular weight 4hydrocarbons or jmore than vided ‘with V.vapor uptakes 238. Lean »absorber four mole viper cent :of :C3 and higher molecular oil is withdrawn from the bottom of stripper 2:28 Weight hydrocarbons. AHeavier gases including through »line `cooled in Watercooler 242 to :a propane, -butana :and :even unsaturated .higher temperature «below 106° F., and returned `to ac molecular weight `hydrocarbons may be used. cumulator 2534. it will he apparent that »the rich ~> The agglomerati-ng material, as has been stated, oil from absorber »i2-ii?. can be used to ,partially may be >either'catalytic or Vnon-catalytic. If the cool the lean oil from stripper' il?, .by providing material is non-catalytic, the >reaction is con a suitableheat exchanger. Fresh absorber -liquid. ducted kunder substantially Ythermal conditions is I'added to :accumulator 294 -as required .through and the agglomerating material used ‘may'com line 2.44.

prise -sintered alumina, silica, fdiatomaceou-s earth,

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Liquid carbon .disulfide is »Withdrawn from ac of .the'carbon disulñde may be pumped >through ,

and pumice. >Suchxnaterials‘should have :a par» ticlesizesuñicientto through -a Í100 `to .200 mesh 'screen in order that -they vmay -be vproperly ?luidized. If `a moving >bed process is used, -the

line .252 -to the upper portion of stripper 2i8 as redux. The Ístabilizer :25d is operated at pres

pellets may measure from 1/8 inch to %;inch. `In conducting the thermal reaction, the zpurpose of

cumulator i226 through line 2th and charged lby means of pump 248 to stabilizer 25d. Aportion

.

sures of 20 pounds per square inch gauge or

the inert ` agglomerating‘material` is `«to "‘fscavenge”

above,1and,preferably inthe ranges of 5€) to -150 pounds. The temperature in the bottom of the stabilizer is that needed to eiiectivel-y boil the >carbon disulfide Iand >free it of >hydrogen .sulfide and hydrocarbon gas under the »conditions of operation. The stabilizer 25B is equipped with surfaces 254, such as Raschig rings, with apla'te 253 having vapor uptakes 25B and a re .boiler 25S. In the stabilizer 25d, any hydrogen

the tarry rand <.polymer--containing by-produc'ts,

sulfide or »hydrocarbon gas absorbed in the car

bon disulñde is boiled off and es overhead through line 2&2 through Water cooler 254. A small amount of carbon disulfide es over

head, is condensed in part in cooler 2â4,~and collected in accumulator 266. The condensate from accumulator kit@ is returned to the top oi

the stabilizer through line 268 by meanssof pump 210.

The uncondensed _gases and vapors are »

withdrawn from the accumulator 266 through line 212 and recycled to the inlet `oi .absorber >2il2 .through linelûíl. The bottoms from the sta bilizer 25.0 are withdrawn through a pressure con

trol valve 214 .and charged through line 216 with Ãthe necessaryheating or cooling, `to the middle

portion >of fractionating column l2.78 from which the carbon disulhde is .taken overhead through line 28B, condensed _in water cooler 282 »and col lected in accumulator k28A as ,iinished product. Any bottoms, such as absorption oil, which may have ed overhead with thefcarbon disulfide 'from stripper 228 are withdrawn from the bot tom o'f the fractionator 2‘i'8 through line 236. Fractionator 2li? is equipped with surn lfaces 238, such as Raschig rings, a separator

and 'vfor this purpose only a relatively small ' amount of inert material in relation' to'theamount

of :Charge reactants Ais znecessary. Generally, the amount .of fagglomera‘ting material will need vto be suñicient ïtozocclude 'all of .the tarry `products inherently :present in -the hydrocarbon ¿charge under the'operating conditions employed. Gen erally, this :amount 'will -vary -from about dive `.to

fifty weightfper cent lba‘sedfon :the Vtotal yWeight of charge reactants. `The thermal'freactiontmay be :conductedîat from about 842° Á.to l650° F., lAlthough hydrocarbons higher Yin molecular Weight than .fmethane will react thermally with -sulfur vapor :fat'compara

tively moderate temperatures, this technique requires long ïtim'esand, asia-consequence, dehydrogenation and :tar'iormation ‘reactions Vare increased relative to that 'of carbon disulhde formation. .Atîmore elevated temperatures vWhere the lfrate ‘of .carbon disulfide 'reaction "is rapid, these side'reactions'will è'be minimized `-and any

previously .dehydrogenate'd products -that may have 4`formed `.Willareaot ‘with sulfur to form ad ditional "amounts .of carbon disulñde. For ‘these

reasons, .the preferred thermal 'reaction'tempera turerangesîfromlQSZ" .F.lto '1500" 1F. with adequate residence time within .the reaction .zone for car bon 4disulfide formation. These >reaction or residence‘tim‘es -will vary .according to the tem

perature .employedand .according to the type of hydrocarbon charge gas used. ‘The preferred reaction times "are in .the order of 0.5 to '25 sec

onds `under .atmospheric pressure conditions. plate 2.3i) having vapor uptakes 2&2 and a re When higher pressures yare used, vthe reaction ‘boiler 2M. Fractionator 218 is preferably oper times `Will fbe v'relatively increased. ‘Since unsat ated at atmospheric pressure. The finished >car urated hydrocarbons react'more readily than sat bon disulfide is Withdrawn from the accumulator 70 urated hydrocarbons, with other factors being284 by means of pump 28E through line 298 to equal, .the reaction time for the former »will be

storage. .A portion of the carbon disulfide may he .recirculated through line .3M as .reflux >to y.the

lessened.

topof the fractionation-278.

lwill »serve .to both vpromote `the lreaction and,

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4„Semeral catalyticmaterialsare available which

-Having thus’described `the apparatus “useful in .175 when used according to the ïmethods outlined

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tion products. These materials include synthetic silica-alumina, silica gel, fuller’s earth, bauxite,

mass. The temperature of the regeneration may be controlled by recycling into the regeneration zone a portion of the regenerated agglomerating

activated alumina, and in general .thosetypes of clays Ywhich are effective in theiremoval of color bodies and gum-forming bodies from petroleum oils. These catalysts may be used alone- or in

of cooled recycled agglomerating material is de

here, will serve to remove deleterious side reac

material after this portion has been cooled toa suitable temperature in aV cooling zone extra neous of the regeneration zone. The quantity

pendent upon its temperature, and decreases with decrease in temperature of the cooled recycled material stream. Common practice is to with draw the cooling material stream from the dense conium on silica gel or activated carbon are es phase of the mass Within the regeneration zone, pecially eiîective catalysts. Oxides of titanium cool it to the desired cooling temperature and and thorium may likewise be used. In addition, recycle it -to the regeneration zone. the oxides and sulfides of iron, vanadium, chro It is apparent from the description thus ffar mium, molybdenum, and manganese may be used 15 that the method of operation of this invention as` >promoters in combinationv with silica gel, permits the >continuous eñîcient conversion of fuller’s earth, or activated alumina catalysts. higher molecular Weight hydrocarbons into car «When conducting these reactions catalytically, bon disulfide. By operating in accordance with lower temperatures maybe employed, the pre ferred range> being from 842°. F. to 1300°YF. For 20 the invention, these higher hydrocarbons are reacted almost quantitatively _to carbon disul both Athe catalytic and thermal reactions, it is fide with continued high catalyst activity preferred to use about the stoichiometric amount throughout the reaction. This isV inherent in the of sulfur needed to react'with `all of the carbon process since the reactants are'- continually be and hydrogen ofthe hydrocarbon to form car ing ed with fresh or regenerated agglom bon disulîide andk hydrogen sulfide. Theratio erating material under either thermal or cata of lsulfur to hydrocarbon charge gas may, »how lytic conditions andthe agglomerating material ever,»vary considerably and it is preferred to op is continuously removing the deleterious side re-. erate with an amount of sulfur between 10 per action products from with the reactants> cent in excess Aof stoichiometric requirements and 110 per cent below stoichiometric requirements. 3 0 during their combination to .form carbon disul ñde and from the atmosphere of thexreaction. Within this range, reactions leading to the forma The sensible heat carried by the regenerated ag tion of low boiling sulfur compounds such as mer glcinerating material, when recycled back into captans and alkylsulñdes are minimized and at the liquid sulfur stream, will aid in the Vapori the'same time the amountof recycle sulfur that zation of the sulfur 'and its subsequent super would have to be regenerated with the tarry heating. The present method also provides an products is limited to avreasonable amount. Al efficient means for the reclamation of the sulfur though the-reaction has been described through content of they tar or free sulfur ixed or in the use of the iluidized technique, other methods solution with the tar for recycling in the'proc' may be used tov circulate the »catalyst »or ag glomerating material through the system.- VThese 40 ess. Lastly, sensibleheat is provided >for the reaction itself under endothermic conditions of include movingbed methods such as those em combination with one oivmore; compounds of metals of groups IV, V, VI, VII, and VIII of the periodic table -»as promoters. The oxides of zir

operation.

_ ployedin pebble heaters and in Thermofor crack

ing processes.

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f

` kThe following examples are given to illustrate

Another procedure 'consists in

the invention:

mixing the agglomerating material to~~form ar

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_Example 1.-Substantially pure ethane- gas wasL

slurrywithfthe liquidsulfur to be charged to

reactedv with, a stoichiometric amount of sulfur

the reactor.- « An alternateprocedure comprises

vapors at 1112c F. in a »fixed bed reactor. Ini fluidizing the» agglomerating material with the tiaily only a small amount oftar formation was sulfur »vapors at apointafter vaporization and experienced. However. after a few hours, con~ „ before orßduring the super-heating of the‘sulfur. A »preferred feature of> the thermal technique 50 4.version to carbondisulfide had declined from its initial level- of .90 per cent to a value in the order> is to- separately »preheatthe sulfuryapors and of 20 per cent, and it was necessary to reactivate hydrocarbon charge gas up toreaction tempera tures and then combine these preheated streams immediatelyV prior to their entrance into `thefre action zone, This procedure overcomes thel de' hydrogenating effect of hot sulfur y»von the hy drocarbons with subsequent coke formation. Whether ` thermalÀ or catalytic; »the rreaction

the catalyst.

t of pentanes and >0.5 percent hexanes and heavier

hydrocarbons was ed at substantially at-_ mospheric pressure intoa reaction zone Jmain

conditionsand proportions of reactants may vary

somewhat~depending~onthe type `of charge gas employed. Based on reaction conditions of about 1112" F. and atmospheric pressures »the weight

ratio of agglomerating material to charge-gas

_,

Example AfA natural gas containing 91 per centmethane, v5 per cent ethane, 2 per cent pro pane,l 14 per cent of C4 hydrocarbons, 0.5 per cent

60

ktained at a temperature of 1112° F. and fitted.

with a static bed of silicagel catalyst. Employ ing a stoichiometric ratio of gas‘and sulfur at a total space velocity of 450 (gas and sulfur (S2)

may vary-from.- 1:1 -tof20:1 with theßpreferred

volume calculated at 0°

range -being 2:1»to 10:1 and thermedian about

¿niercurw , a conversion _of 58 per cent ofthe hy

5:1. ' yThis may be based on either a 10 per cent»

deficiencyor 10 percent excess of sulfur based on stoichiometricity.Y

IIYhe regeneration-of used agglomerating ma-_ vterial Íis' eifected by suspension» ofthe particles. »in an oxygen-containing gas and age,V of the suspension> through a „regeneration zone under conditions adapted to cause combustion of the

and 760 millimeters of

drocarbon gas to carbon disulfide was obtained. It was found Aunder these. Iconditions »that com peting side reactions occurred to such an extent Y that aboutA 2 per cent of the charged gas 're--y

acted with the sulfur to yield a viscous tarry polymeric material .and some coke, With the re- '

sult that a material decrease in over-all >eiiiciency and catalytic activity followed. Recovered Vsul

_fur .was around 40`per cent'of that charged.' An facethereof. during > .Withthe reaction 75: initial high conversion-'of around 76 per cent

occluded tars andpolymers .1 collected on the sur.- .

acca-,69o

l2

lîlî

of. stoichiometric requirements. for the reaction;`

was attained fora period of about one hour after

which conversion dropped gradually and after. about six hours’ operation, conversion leveled off

7. The method in accordance with claim, 1> in

at about 58 per cent. Example 3.-A natural gasv containing around 3.0 per cent of C4 hydrocarbons and heavier is ed through a ñuid reactor using the iluid technique in the presence of the. saine agglom erating material or catalyst as used in Example 2. The reactor. is maintained at 1112o F. under ‘il

substantially atmospheric pressure conditions. rIv‘he sulfur to gas ratio is controlled to approx

imately stoichiometric requirements. The Weight ratio of catalyst. to natural gas is maintained at about 6:1, and the. . time is about ten seconds. The over-all conversion of the hydro«

which the oxidation of occluded sulfur-contain ing by-products on said agglomeratirig material Vis conducted at temperatures in the order. of 800° F. to 1500L7 F. 8. The method in accordance'with claim 1. in which the reactants and agglomerating material aremaintained in a I'luldized state Within the re

action zoneat about 1112° F; under s'ubstantlally;

atmospheric pressure with the ratio or' agglom erating material to hydrocarbon being mains> tained at about 6:1 with a time of about 10 seconds. 9. ‘ille method inv accordance with claim l in Whiclithe sulrur dioxide and hydrogen sulfide. are reacted at temperatures Irom 500° F. to 150° F. in the presence or a catalyst capable oi' promot

carbon. gas over. a period of 12 hours will bev about. 90 per cent. of .which 88 per cent appears. ing the ioi'mation oi' elemental suliur; as carbon disulñde, and 2 per cent as tar. Ten 10. The method or continuously producing car per cent. of the natural gas remains. unreacted 20 bon disulfide by reaction or hydrocarbons and and 'substantially 10 per cent of the. sulfur is un sul'i’ur, said hydrocarbons containing substan reacted.

From the. above examples, it isseen by em ployingA the technique ofthe present _invention the. .deleterious eiîect of side reaction products .

eliminated andtheoverali reaction efficiency is

tial amounts 0I constituents tending to i‘orm dele-

terious tarry suliur-containing by-products comm pi'isillg, ing preheated nydl'ocarbonsv and preheated suli‘ur vapors with an agglomerating.

maintained. atv a high level. Although the inven

material in_a reaction zone under conditions ca

tion has been described by speciñc embodiments,

pable ol tlieiormation oi- carbon uísuliide and hy

these. are only illustrative and the only limita tions. to be placed. on the. invention are found in the. appended claims.

drogen sulfide;4 said agglomerating material being,

. What is claimed

1. The method of converting hydrocarbons to carbon disuliide by reaction Withzsuli'ur, said hy drocarbons.. `containing constituents tending to form tarry sulfur-containing. by-products, com prising ing preheated hydrocarbons and pre heated suli‘ur vaporsv into With an ag glomerating material in a reaction zone, said ag

capable 0Iv occludlngv said, Sulrurf-containing by products, sepa-rating carbon-_ disul1ide„ hydrogen sulfide, and said agglomerating material iroin. eacii other, subgecting saidagglomeratlng, ma. terial to an oxidizing atmosphere capable 01‘ pro-_ ducing sullur dioxide _ :rom said occluded by-4

products, reacting. said suli‘ur dioxide and said Sûpai‘ated hydrogen sliliide under conditions ca.

pable or forming elemental sulfur. il. 'The method in accordance with vclaim 10

glomerating. material being capable of occluding 40 in which the agglom'erating matei'ial’isv selected saidisulîurecontaining by-products and-said reac tion zone being maintained under conditions to promote. the formation of , carbon» disulfide and

hydrogen sulñde, separating said agglomerating material and. the` carbon disuliide and hydrogen sulfide so.` formed, subjecting' said agglomerating material to. an oxidizing atmosphere capable of oxidizing the sulfur contenter said» occluded by products to. sulfur dioxide, and reacting said sul fur dioxide so. produced With- the hydrogen sul fide under conditionsV to produce elemental sul~Íur for reusein the reaction. 2. ri‘he method in accordance withy cla-im 1 inl which the aggl'omerating` material is selected fromy the. group consisting of sintered alumina,Y

silica, diatomaceousr earth, silica» gel, activated alumina, vactivated clays,- and‘silica-alum-in’a coin' positionsi.

_

`

3. _The. method in. accordance with claim 1- inf whichl the hydrocarbon isselected from- t‘he group consisting of natural. gas, propane, butane, and their existing oleñnie homologues and mixtures thereof.

-

=

»

'

Which the. carbonv disulfide forming reaction is»v .

conducted ata temperature between about 842° Rand 1500° F., and the ratio of agglomeratingy material: to hydrocarbons. is in the range'of 2:1 `

-

Y'

_5. `'I‘he method in accordance with claim 1 in Which the hydrocarbons. andsulfur are preheated`

to reaction temperature._

silica,y diatoiiiaceousv eartn,_,sillca gel;î activated. alumina', activated clays, and silica-alumina coin positions.

_

v

f

l

Y

l

_

Y

_

iz. 'i ne-method,in_accordance with claim 10 in which the hydrocarbonisselectedrroin _the group consisting 0I' natural gas, propane, butane,` and their existing» olennic homologues. and mixtures thereof.

l

_

_

13.. ',L‘hemethod in accordancerwith claim 10 in which the carbon. disulfide vIorining reaction is.

conducted ata temperature betweenwabout 842° l?. and 1500u Fi, and the ratio of agglomerating, material 11o-hydrocarbons is in the. range of 2:1. to` 10:1..

p

ì

i4. 'l‘heìmethod in accordance with claim 10 in which the hydrocarbonsand suli'ur are pre heated _to reaction. temperature. _

15. 'I'he method in> accordance With` claim 10 in which the sulfur. is present in 4an amount be " tween av lo. per cent ld_.en'ciencyand a ll) per cent

excess of stolchiometric requirements for the re action

Y

`4. rThe method in> -accordance with' claim» 1 in

to„10:1.A

rrom tile group consisting o1 sintered alumina,_

_

__

_

_

_

lo. VThe method of converting hydrocarbons to carbon disulfide-by reaction with sulfur, said h_y drocarbons containing' constituents tending to formtarry suliur-containlng by-pi‘oducts,l y coin

pi‘ising ing preheated hydrocarbons and pre» heated sulfur vapors into Withan ag glolneratlng; materialin areaction zone, said ag gloinei'ating material being capable of occluding saidsuliurscontaining by.-products and saidreac

6. _The method in accordance With claim 1v in. tion zone being maintained. `under conditions to. Which the sulfur is present in an amount betweenA promote the iormation` of carbon disulfide and» a4 I0 per cent deficiency anda 10 per cent excess 75 hydrogen suliide,A separating said. agglomeratingY

2,666,696 13

14

I

material and the carbon disulñde and hydrogen sulfide so formed, subjecting said agglomerating

`References Cited in the ñle of this patent UNITED STATES PATENTS

material to regeneration in an oxidizing atmos

phere. 17. The method in accordance with claim 16 in 5

Number

Name

Date

2,187,393 which the oxidizing atmosphere is an'oxygen 2,330,934 containing gas. Y 2,389,810 18. The method in accordance kwith claim 16 2,480,639 in which said agglomerating material is a cat alyst capable of promoting the formation of car- l0 2,487,039 2,530,243

De Simo>______ _'_____ Jan. 16, 1940

2,556,177

Gamson _________ __ June 12, 1951

bon disulñde from said hydrocarbons and sulfur. HILLIS O. FOLKINS. ELMER MILLER.

HARVEY HENNIG.

'

Thacker __________ __ Oct. 5, 1943 Odell et al. ______ __ Nov. 27, 1945 Ferguson ______ __ Aug. 30, 1949 Belchetz ________ __ Nov. 8, 1949

Holder __________ __ Nov, 14, 1950