US1091689A - Methob of producing sui - Google Patents

Description

H. E. MOORE a; R. B. WOLF.' METHD OP PBODUCG SULFUR DIOXD.

APLICATIDS FILED FES. l. 1910.

Patented 11181.31. 1914.

, ...QQ @Q UNITED STAES OFFICE.

HUGH K. HOIORE AND ROBERT B. WOLF, 0F BERLIN, NEW HAMPSHIRE.

METHOD OF PBODUCIN G SULFUR DIOXID.

Specication of Letters Patent.

appueatibn mea mima-y 1. 1910. serial m. 541,245.

Patented orar. 31, 1914..

To a?? zz-Imm it may conc-ern Be it known that we, HUGH K. Moons and Roem B. WQLF, both of Berln, in the county of Coos and Stute of Sew Hump shire, have invented certain new and useful Improvements in Methods of Producing Sulfur Dioxid, of which the following is a specification.

The present invention has for its object the commercial production of sulfur doxid in condensed or liquid form, so that it may be properly controlled, handled= transported or conducted.

In carrying out the process, we subject the sulfur bearing material to combustion, and then from the ses which result as a productof the com ustion, the sulfur dioxid. is separated and is converted into liquid state. We propose to utilize calcium chlorid and water asl the solvent or absorbing medium for separating the sulfur dioxid from the other gases resulting from the combustion of the raw material, for the reason that it can be refrigerated to relatively lou temperatures, viz. to approximately 440 F.

before the solution will solidify, whereas water solidilies quickly at approximately 32 F. Moreover the addition of calcium 'chlorid (09.01,) raises the boiling int of water without a preciabl raising t e boil' ing pointof sul r dioxi dissolved therein. Hence, when the solution of calcium chlorid,

water and sulfur dioxid is subjected to vaca um to lberatethe sulfur dioxid, less water vapor is given oil' than would otherwi be the case. One of the advantages due to the liberation in 'vacuo of the sulfur dioxid from the solution is that it reduces the temperature of the solvent to an extent ual to the latent heat of volatilization of sul dioxid, and conversely (muni no chemical ac tion takes place) the absorption of the sulfur doxid by the solvent rals-the temperature thereof to an extent equal to the latent heat of Iiquefaction. Hence the initial r efrigeraton of the solvent, which we employ as a step in our process, need be sullicient merely to extract the heat conveyed to the.

solvent by the passage therethrough of the unabsorbed gases, and what heat is conveyed to the solvent by conduction from the atmosphere outside the casing. We reduce the temperature of the gases entering the' absorbing apparatus by an exchanger, chilling them by the waste gases discharged from the absorbing apparatus, thus reclaiming,

as it were, a large partof the initial refrig-- and which are illustrated upon the accompanying The drawing, which illustrates one exu- .ivhich are hereinafter specifically described bodiment of apparatus, represents the me c hanical structure in a. smewhat conventional manner. r

The samereference chaiflacters indicate the same parts wherever they occur.

' On the drawing, 10 indicates a cylindrical rptary burner provided 'with tapering portions near one end and with cylindrical extenslgns 11 and 12. The burner has exterior llanges resting` upon su porting rolls 13 13 aiiixed upon parallel pulleys 15. The neck or extension 12 ex# tends into a box 1T and is surrounded by a stujling box 1S which furnishes a bearing and prevents the escape of 19 indicates a feed ipe bearing material, leading from 'a spiral confor the raw afts 14 rotated by veyer 20, inclosed in a cylindrical casing 21 a `re1 hopper 22. The conveyer 20 is driven y a pulley 23.

The delivery end of the burner ismounted in a stuliing box 24 and delivers the burned material to a casing 25, which is closed save for the inlet pipe 26, thro vh which either air or pure oxygen is snp hed; The selection of air 'or oxygen may determined b the nature of the substance which is b or ma he determined by the of the gals. w 'h it is sought to produce'. The suldioxid s, together. with other gases which may the products of combustion, are conducted from' the bo`x 1,7 to a cooler or coolers througra pipe 27.

The present invention provides two coolers 28 and29 forthegaseswhich pass from the burner and may be used alternately for the purpose of initially chilling or said gases and condensing those prodnds o combustion, including vapors of sulfurt and gases which have a vapurizmg point higher than sulfur dioxid gas. Each cooler consists of a casing 30, provided with two transverse'heads or partitions 32 which support and through which extend a plurality of pipes or u 33 through which the gases pass, the chambers beyond the partitions 32 areconduotedtoanahsorbingap tus being indicated respectively at 3l and 35., The upper chambers are divided by vertical partitions 36 into inlet and outlet chambers. The pipe 2 is connected. with the inlet chamlbleis by branches controlled bly valves 37. mctice, it is proposed to eep one of the yPalv 37 closed when the other is opened, and vice versa, thus admitting the gases to but one of the coolers at a time. The outlet chambers are provided with outlet pipes 3S, connected to a common delivery ipe 39, and being provided with valves 40. ll'he lower compartment of each cooler is surrounded by a jacket 31, and the interior of the compartment 33 is connected with the interior of thejaeket by a port 31. The space surrounding the tubes 33 is supplied with cold water or an other appropriate medium for coo the gases which man-om the burnerlwater from the orlil: nary service pipes wi out refne'veraton ing preferably used. Either cooler may be' used while the other is being cleaned. The coolingliquid is conducted to the coolers by pipes i1 and is conducted away from the` water jackets by return piges 42. c

To remove the sublime sulfur from the pipes of a oler, the valve 43 of the sup- Kg pipe 41 closed and steam or any other tang medium may be forced into the s ace surrounding the tubes 33 through sup` p y pi-i provided with valv 45. When the tu become sniciently heated by the htmga "he S p` m t e i Pm-g geiles into the chamber is disch rough an outlet 46 having a valve 47. The pipes 42 may be provided with steam traps 48.

Thegases ,passingfromoneortheother of the coolers into the pipe 39, are conducted. to an absorbing,r apparatuss containing an absorbing liquid or a solvent which will dissolve the sulfur dioxd as hereinafter explained. A pump or blower 49 may be provided in the pipe 39 between the coolers and the absorbing apparatus. The gases may, if 'desred,passd1rectlyfromthecoolersto the pum or blower ,49, or they may be conducted) a seco cooler, condenser or absorbing ap tus 50 controlled by a valve 51. The coo im as 50.32211 'i a 41r pure oxygen 1s in u to e burnerinstead-ofair,forinthatcaseitis to condense and se te the sulfur trioxid resul from combustion, as, hereinafter exp ained. A bypass 52, havin a valve 53, is provided in case it is d toconduct the gases directly to the blower@ without conducting them through the cooler 50. From the blower 49 the gases whichcomprisesacasingtando appliances to be described. Thepipe 55,counecting the blower and the casing'54, is

arranged to conduct the gases to a horizohtal plane as high as the top of the casing 5l before introducing the gansos into the casing, the object being to preventan overflow into the pump 49 of the liquid contained in the casmv 54.

56 indicates a body of liquid in the casing 54 for absorbing the sulfur dioxid. Any preferred absorbing medium may be employed for this purpose, although for rea sons hereinbeore given, we recommend and prefer an aqueous solution of calcium chlorid. Since the absorbing capacity of the absorbing medium is greater when the temture thereof is relatively low than when 1t is relatively high, we keep the temperature of the absorbln medium in the casing 5l as near as possi le to v3:2" F. or lower. The cooling of the absorbing medium mayA be eec'teddeihthe-rlvithinStg, without; Ithle'gcas mg an e wig ows a coo a paratus within the casing and separate cool: lng apparatus without the which may be regarded as equivalents. e interior copllsinsg ppatlilalu: consists of the council-.ted co T or ere'ig'verantarrangedin ayers su rted b tlngs or rforated titiond, Th?!v gilet 5.9 is dbentrolled liyua valve 60, the outlet being indicated at 61. The cooling eect of the coils 5T is obtained by forcing a refrigerant through them. The external cooling ap aratus for the absorbing medium 56 incud a coil located be-` tween a pump 63 and the pi 64 which conducts the cooling'liquid to e inlet near the top of the casing 54. i

One object oxproviding the coolers 28, 29 and 50 is to fa tate the absorption of the gases by the absorb medium 56 by reducingthetemperatureo thegasesasnearlyas possible to 32 F. or lower. For the sake of economy, the coil 62 may be arra ed out of doors in cold weather, to be cool solely by'the out-of-door temperature, but in warm weather it may be included in some commercial refrigerating apparatus.

The gases= other than sulfur dioxid, which pass with the diod into the bottom ofthecasngnsetothetc ofthecasing andpaoutinachilledorre tedcondition a pipe indicat at 65. To collect an sulfur dioxid gas which escapes through ipe 65 with the other gases, a supenmpedpcasing 66.may bel-provided to contain a separate body of abso v liquid. For this purpose, the end of the pipe 65 is sealed by the absorbing liquid. The unabsorbed gases, after passing through the absorbin duid in the easing 66, may be eonduct to any desired point by a ipe 67. The compartments in the casing 54, een the forated partitions 58, are connected by e overflow pipes 154, 155, so that the ion 'absorbing medium is conducted downward th h, and as a result the absorbent is strongt in sulfur dioxid in the bottom erator is automaticallyr indie Ill mi) Awillig of the compartment c and weakest in the top compartment a, thereby allowing more complete absorption through the casing. Otherwise the solution would be of the same strength in sulfur dioxid throughout, and a greater amount of sulfur dioxld would escape from the casing. The openings in the perforated partitions 5S must be small enouglho) prevent the absorbentfrom pasing one comparhnentto' the other. The minste or una gases are employed for the purpose of absorbing the heat of the gases entering the absorber, and are conducted to an exchanger illustrated conventionally at 106, and co`nsisting of a easing which receives the cold waste gases from' the pipe 67 and discharging them from the pipe 6T". The waste gases and the gases from -the blower travel past each other in their respective conduits (the casing 103 and the pipe 67) in opposite directions.

The absorbing uid 56, containing in solution the sulfurdioxidgas, passes from the casingth'ro api toadevicein which the sulfur dioxi gas is liberated in vacuo from the absorbing medium and which is termed a gas liberator. The pipe 68, before entering the gasliberator, passes to a horizontal substantiall 2S feet (more or les) a ve the top of t sothxttheliberatorwillnotbeood with the solution, As the level of the solution in the absorbing tank is lowered, the golumn of soluttlilxn in the (pipe 68 mrc m .tank increases, an consey P of the solution to the libcontrolled. .'Ihegaliileorsadtorlsindicatedat 69apd colisstso a elsing' con apuhorizontal relation, each plate terminating a short distance from one end ofthe casing. The absorbing liquid being deposited upon the upper plate 70 flows in the-form o a thin lm or layer (approximately to i of an inch in thi over the plates 70 successively until it reaches the return pipe T1, which conducts'it back which itis in forced l coil 62 an the easing '54. The liberation of the dioxid gas from the absorbing uid is efected by subjedzing the absorbing duid' and the gastosvaeuumwithinthecasingtt). By reasonoftheyacunmwitlnthecinga larga-portionofthesulfurdioxidg'asisremovedfrmitheahsorbingli 'd,si:ncethe liquidin the 69 is uced to thin iilmsasderibednr eatthesametmethe of the water in the absorbing'me dinnilsreduced. '111cgas,thusliberated,is eondimted by a pipe 72 to a. gas condenser by which it may be converted into a liquld eonditonbeforeitisdeliveredtoareceiv- -5ingorastoringhamber.Thegascon balr into sulfur denser 'comprises a closed casing T3, having the pipes T4, the vertical partitions T5, the staggered horizontal partitions T6, and the partitions 7T, 77, the latter dividing the space between the plates 5 and the ends of the casing into two compartments T8 and T 9. The gasintroduced through the pipe T2 into the casing 73 passes around the exterior of the pipes 74: and also pases back and forth around the ends of the partitions 76, and the liquefied sulfur dioxid is conducted by pipe 60 into a. vacuum chamber 81. An other. type of condenser desired may be use The liquid sulfur dioxid delivered into the chamber 81 flows through n. pipe 82 to a receiving or storage tank 83, from which it may be drawn through au outlet cock 84. A basin 85 may be arranged below the cock 84: and mav be provided with a filter 86 and with an outlet 87 adapted to deliver the liquid as into portable receivers or tanks such as at indicated at 88. The storage tank 83 and likewise the pipe 82 and the vacuum chamber 81 may be surrounded by the same cooling medium which is employed in the gas condenser 7 3 to convert the gas into a liquid mte. For this reason, the tank 83 and the pipe 82 and the chamber 81 are inclosed by outer casings indicated respectively at 89, 90 and 91. Any appropriate coo 0' medium and apparatus may be em loy forthis purpose, that shown by the wing consistmg of a gas compressor 92 and a condenser 83 connected in a circulatintrsstem includmg said Passing v the condenser, tligrneigera v gas is ally conducted a pipe 95 bac to the compresor 92, and e cycle of cooling medium is thus completed.

The vacuum, by which the dioxjd gas is liberated from the absorbing fluid, may be produced by a vacuum pump such as that connected to the vacuum chamber 81 by the pipe 96, and which is of the reciprocatory type and includes two vacuum cylinders 97, 9'( placed in series and containmg P 99,actuatedbyathirdpistonf up. in a cylinder -101. It may be stated t care hlolllld be taken to provide a liicilrlit verti engtho pipe 82 greater an c height to which a column of liquid gas istons 98, 98, aixed to a piston rod would be maintained by atmospheric pressurein a vacuum tub'e. If desired, a device 102 comprising` a casing containing :u1A absorbent' may be inserted in the pipe 96 to ,collect' whatever sulfur dioxid gas remains lmcondensed and would otherwise be ex hausted by the vacuum pump into the atmospher'e. In case it-is desired to effect the liberation of the sulfurdioxid gas from the absorbing duid by means of heat, the vacuum pump would not be necessary.

Although the method and apparatus, now completely described, are intended primarily with a. formation of some S duo to an uneven mixture of the oxygen; or

These and other motions not specified zo maytalceplaallattbesamehme.-

Thegases fromtheooolersmaybe further cooled ore going. to tbe blower, 49 by being through the cpoler 50,

the effect of which is to condense out the suifur trioxid and the sulfur dioxid then can be conducted to the various pieces of in the preliminary coolers 28 or 29 is suhst-untally that at which the water is drawn from the river or from any usual source of supply, and 1t is for this reason that tho action of said niedlum is described as cooling. This preliminarily reduces the temperature of the products of combustion at small expense. The temperature of the coolmgh medium in the secondary4 cooler 50 (w en oxygen only is used to proinote combustion in' the burner) is sultantally 14 F. more or less. The temperature of the solvent (calcium chlorid solution) when introduced to the absorbing tank 1s suhstantially 32 F. more or less, and consequently we term the reduction of the temperature of the solvent, ting it.. The temture of the retr t in the condenser when sulfur dioxi gas is condensed in vacuo) is ,-90 F. more orls.

We claim: 1. The herein dcrbed method of obtaind .sulfur dioxid, which o o owmgsteps, tow1:-pa1ng e roducts of combustion con sulfur oxidandothergusesthnoughasoventreted to a tem aparatushereinbefore described forrst frlgera perature 4 y ahsorbing, then liberating, then condensing 3? and capable o f absorbing sulfur andiinallysto thesntilelnliquid condi etxractilng an vedono aoon. 'l'hebuctso operationmay' 0X1 -esovenan .11; also be ferricpoxid or ferrous od, sulfur the dioxid gas moaouo, to

and auhydrid. If the oxygen is suici 'ently ggg-Itho gas from the blower 49maygo -ytothe condenser'i' :is4 without passing through e absorbing ap paratus and the liberator.

The purpose the absorbing and hberatapparatus" is to remove mtrogen and er gases which accompany: the

40 dioxid when air instead of pure oxygen is used for 'ving combustion. This'is an 1inportant p.ase of the invention for the fo1 lowing reasons: Where the products of combustion from the burner are paed ofthesulfurdioxidgasisabsorhedsothat the resulting solution contains substantially 2.5% of nncomhined sulfur dioxid. This is due to the fact that 'the products-oi comso bustion comprise quantities of nitro-' carbon 65 thatthotemperatureofthecoolingmedium through 45 milk of lime, b ut a relatively small quantity bstan, sulfur di lhsorbf i v--lv liqueflit. 2. e herein described method of sulfur dioxid, which consists in thi ollowmg steps, to witz-burning a.sulfur fog healing material, posing thel products of combustion therefrom through a body of solvait for the sulfur dioxid gas, distributing the solvent and the gasahsorbedthereb inthinlayersinams vacuum chamber, the sulfur dioxid gas n vacuo from said thin layers, andi the liberated-gas is vacuo to qu 1t.

3. The herein described method of obtaininolsulfur dioxidgaswhichoons'mtsinthe fo owing steps, to winse from the products of combustion o a sulfur bearwhile siidutionisre'lgerated' toa proxmately 32 F., and then extracting eacuosaidgasfromsaidreirigeratedsolution.

4. The herein described method of ohtainfing sulfur dioxid, which consists in the fol owin steps,towit:circulating` ahodyo refrigrated solvent, absorbing m said solvent inone portion ot its path sulfur dioxid from the products of combustion of a sulfurbearng material, andliberatmggoacuow ahsorbedgasfromsaidsolventmanother portion of its path.

5. 'Ibe herein described which consists in causing a solvent continuously 13o to circulate from an absorbing chamber to a vacuum chamber and vice vers. refrigerating said solvent, passing pro ucts of combustion of 'a sulfur beari l substance through the solvent in-t-he abso inv chamber forense the absorption of the sulfur dioxicl gr'mantainingsa vacuum in the l da vacuum-chamber an trac-ting from the solventinthe last mentioned chamber the previously absorbed sulfur dioxid gas.

6. The herein described method of obtaining sulfur dioxid gas, which consists in the following steps, to witz-burning a sulfur bearing substance, subjecting the products of combustion to' the action of a solvent capable of absorbing substantially only the sulfur dioxid gas, andQtherebr separating it from 'the other gases or p ucts of com` bustion, distributing the gas-laden solvent into thin lav-'ers and extracting by a vacuum the sulfur dioxid gas from said thin layers of the solvent.

'i'. The method of obtaining sulfur dioxid.

which consists in cooling the products of combustion from burning a sulfur bearing substance, and condensing and -rexnoving the sulfur vapor and those gases having a higher volatilizng point than sulfur dloxid gas, passing the remaining gas through a refrig erated solvent., extracting the sulfur dioxid gas from said solvent in vacuo, and refrigerating said abstracted gas while in vacuo to Iiquefy it.

S. The herein derihed method, which consists in distrib r a solvent containing sulfur dioxid gas into thin laye1s,-subject ing said layers to a vacuum to extract the said gas therefrom, and refrigeratinr said gas while in moua to condense it to iquid form.

9. The herein .described method of obtaining sulfur -dioxij;i`L which consists in burning a material, condensing out of the products of Y combustion those vapors and gases having a higher Vaporizing point than'sulfur dioxid, abstracting su1- fur dioxid from the remaining products of combustion by absorbing it in a refrigerated solvent, and abstracting said sulfur dioxid gas fromsaid refrigerated solvent 10. The herein described method of obtaining sulfur dioxid, which consists in burning a sulfur-b material, condens ing out of the 'products of combustion those vapors and gases having a higher: vaporizing int than sulfur dioxid, emulating a regerated bod of lignin solvent through an absorbing ber and a vacuum chamber successively, pasing the remaining products of combustion through the refrigerated solvent in the absorbing chamber to cause the absolrgetion of sulfur dioxid, liberating the abso nt sulfur dioxld in the vacuum chamber, and maintaining a vacuum-in said vacuuni ch In testimony whereof we have aixed our signatures, in presence of two witnm.

HUGH K. MOORE.

ROBERT B. WOLF. Witnesses:

Manaus B. MAY, Pm W. Pazzi-rr.

Washington, D. 0;"-

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