US2630375A

US2630375A - Method of catalytic desulfurization of gases

Info

Publication number: US2630375A
Application number: US215181A
Authority: US
Inventors: Ernest B Miller
Original assignee: JEFFERSON LAKE SULPHUR CO
Current assignee: JEFFERSON LAKE SULPHUR CO
Priority date: 1951-03-12
Filing date: 1951-03-12
Publication date: 1953-03-03
Anticipated expiration: 1970-03-03

Description

March 3, 1953 E. B. MILLER 2,630,375

METHOD OF CATALYTIC DESULFURIZATION OF GASES Filed MarOh l2, 1951 10 Sheets-Sheet 1 FIG.

1N VENTOR ERNEST B. MILLER @u fw ATTORNEYS March 3, 1953 E.. B. MILLER 2,630,375

METHOD 0F CATALYTIC DESULFURIZATION 0F GASES Filed March 12, 1951A 1o sheets-sheet 2 INVENTOR" n musn ATTORNY:

March 3, 1953 E. B. MILLER 2,630,375

METHOD OF' CATALYTIC DESULFURIZATION OF' GASES Filed March l2, 1951 10 Sheets-Sheet 5 FIG. a. i

, 7? l /00 73 w /71 //7\ /l7 V l /50 i ./,Zfl I /J/ E l Y F I G 'a 4 n y f J w la V I INVENTGR f-L* enuesrammn BY fw ATTORNEYS March 3, 1953 E. B. MILLER 2,630,375l

METHOD OF' CATALYTIC DESULFURIZATION OF GASES Filed March 12, 1951 10 Sheets-Sheet 4 NVENTOR 1 ERNEST B. MILLER BY M71@ ATTORNEYS March 3, 1953 E. B. MILLER 2,630,375

METHOD OF CATALYTIC DESULFURIZATION OF GASES Filed March l2. 1951 lO Sheets-Sheet 5 INVENTOR ERNEST B. MILLER BY VLM ATTORNEYS March 3, 1953 E. B. MILLER 2,530,375

METHOD OF CATALYTIC DESULFURIZATION OF GASES F11ed March 12, 1951 1o sheets-sheet e /7/// 77 a I /65 if 6'/ .l/ o )'70 INVENTOR' ERNEST B.MILLER Armlehnen?V March 3, 1953 E. Es.l MILLER l 2,630,375

METHOD OF CTALYTIC DESULFURIZATION OF GASES Filed March l2, 1951 lO Sheets-Sheet 7 ATTORNEYS March 3, 1953 E. B. MILLER 2,630,375

METHOD OF' CATALYTIC DESULFURLZATION OF GASES Filed March l2, 1951 10 Sheets-Sheet 8 INVENTOR ERNEST B. MILLER BY v/hq,

ATTORNEYS March 3, 1953 E. B. MILLER 2,630,375

METHOD 0F CATALYTIC DESULFURIZATION OF GASES Filed March l2, 1951 10 Sheets-Sheet 9 FIG. I4.

FIG. l5

1N VENTOR ERNEST B. MILLER I BY ATTORNEYS March 3, 1953 E. B. MILLER 2,630,375

METHOD OF' CATALYTIC DESULFURIZATION OF GASES Filed March 12, 1951- 10 Sheets-Sheet lO W n 0 N M e Q Q \J INVENTOR- ATTORNEYS Patented Mar. 3, 1953 METHOD oF CATALYTIC DE sULFURIzATIoN oF GASES Ernest `B. Millen Houston, Tex., assignor to Jefferson Lake Sulphur Company, New Orleans, La., a corporation of New Jersey Application March 12., 1951, Serial No. 215,181

This invention relates to the `recovery of sulphur from gases containing sulphur compounds and has more particular reference to a novel method of recovering elemental sulphur in liquid form from gases containing hydrogen sulphide.

The object of the present invention is to provide a novel method of recovering elemental sulphur from gas containing hydrogen sulphide by catalytically desulphurizing the gas to obtain liquid sulphur.

vAnother object of the invention is to provide a novel method of recovering elemental `sulphur from gases containing HZS in which a catalyst is used which is ableto effect a highly efficient conversion of HzS to H2O and sulphur'and in which the catalyst, after it has become spent, due to chemical reduction of the catalytic agent or the deposition of carbon `or other contaminants from the gas being treated, may be fully restored to its initial efficiency byreactivation with hot air. y

Another object of the invention is to provide a novel method of recovering elemental sulphur from gases containing HzS, as characterized above, wherein the gas to be treated is brought into contact with the catalyst in `at least two successive reaction zones, in which sulphur vapor is formed, prior to its passage to a scrubbing or condensing zone in which the sulphur vapor is condensed to form liquid sulphur,

Another object of the invention is to provide a novel method of recovering elemental 'sulphur' from gases containing HzS, as characterized above, wherein a portion of the liquid sulphur being recovered is returned to a sulphur burner, where it `is burned to supply the oxidant required to oxidize the HzS in the gas being processed.

A further object of the invention is to provide a novel method of recovering elemental sulphur from bases containing I-IzS, as characterized above, wherein the temperature rise in each reaction `zone is controlled by controlling the supply of oxidation gas to such zones.

Other objects and advantages of the invention will appear in the specification when considered in connection with the accompanying drawings, wherein:

Fig. 1 is a plan view, with parts omitted, showing one form of apparatus and the arrangement thereof for carrying out the method of the present invention;

Fig. 2 is a side elevational view of the apparatus shown in Fig. l, and showing the second converter and its appurtenances and the second scrubbing tower and its appurtenances;

Fig. 3 is a side elevational view of the nrstV converter and its appurtenances, shown in Fig. 1;

Fig. 4` is a side elevational View of the `rs't scrubbing tower and its appurtenances, shown in Fig. 1;

Fig. 5 is a plan view of a converter;

Fig. 6 is a side elevation, partly in section, of

the converter driving mechanism;

Fig. 'I is a vertical sectional view of the converter, taken on the line 'l--l of Fig.` 5,' but omitting the driving mechanism;

Fig. 8 is a horizontal sectional view of the con# verter, taken on the line 8- 8 o f Fig. *7, butdrawn to a smaller scale;

Fig. 9 is an enlarged vertical sectional view of" the seal shown in the right hand side of the upper manifold of Fig. 7;

Fig. 10 is a plan view 'of the seal shown in Fig. 9;

Fig. 11 is a vertical sectional'view taken on the 14, 'and Fig. 16 is a diagrammatic view showing the ilow of the gas to be desulphurized; the low of the oxidation gas; andthe now of the 'regenerating medium 'through the system.

In general, the invention comprises a method i of catalytic'desulphurization of gases containing hydrogen sulphideyand'the recovery `of elemental sulphur therefrom in liquid form.

For the purpose -of illustration, the rinventio will be described in-connection with the catalytic desulphurization of sour natural gas and the. recovering of elemental sulphur therefrom in liquid form.

Referring now to the drawings, there is shown,

in Figs. l to 4 inclusive, one embodiment ofap paratus and the varrangement thereof for carry ing out the method of this invention. The ap.- parat-us shown includes a iirst three-stage 4rotary catalytic `converter or reactor 5, two stages of which are used `as reaction chambers or zones, in which the sour gas is brought into intimate contact with the catalyst, and the other stage is used as an activation chamber or zone in which` the lcatalyst is regenerated.; .a rst pre-heater 6 for heating the sour gas prior to its passage through the `iirstreaction stage of the converter` a heat exchanger 1 for heating or cooling the sour gas between the first and second reaction stages of the converter 5; a first scrubbing tower 8 for separating the liquid sulphur from the treated gas; a second three-stage rotary catalytic converter 9, two stages of which are used as reaction chambers or zones in which the sour gas is brought into intimate contact with the catalyst and the other stage is used as an activation chamber or zone in which the catalyst is regenerated; a second pre-heater Ill for heating the sour gas after its passage through the first scrubbing tower and prior to its passage through the rst reaction stage of the second converter 9; a second heat exchanger II for heating or cooling the sour gas between the rst and second reaction stages of the second converter 9; a second scrubbing tower I2 for separating the liquid sulphur from the gaseous admixture after its passage through the second converter; a heater I3 for heating the regenerating medium. preferably air; a fan or blower I4 for supplying air under pressure to the heater I3: a sulphur burner I5, in which a miYture of liouid sulphur and air is burned to produce a gas of combustion having as bigh an SO2 content as nossiblepreferably lll-20%: and a waste heat boiler le which utilizes tbe heat of the gases of combustion in the sulphur burner to generate `steam for running auvlliarv machinery and otber purposes. 'The sulphur burner l 5 and the waste beat boiler IE :may be of anv suitable. usual tune. '.Tbe burner I5 is sbovfn as having a liouid snlnlour sunnlv pine I1 connected to sunnlv liouid `sulnbur from the scrubbing towers. and an air surplv pine IR connected to bot air blower I4 for sunnlving air under pressure to the burner.

The two Converters or reactors 5 and 9 are preferably .supported in an upright raised position bv .suitable framework, indicated generally at l l and 20. respectively.

The rntgrv nnnverters E and 9 are identical in crmetmmtinn and are .cene-rauw similar tn the man.. verter shown, in uw nnngnding avnliparinn, ,cmg Nn. '779 R24- 51er] flntnloer 14 104'7` for llfl'etlanfi nf and. vArmar-atm@ for l'ieeulnburi'zatien of Gases, now TT. S, Tetters Patent No, 9.561900 issued .Tulv 24. 1951. 'Tbe details m the converter are shown in Wigs, 5 to l5. inclusive. As there sbown. each nf tbe Converters comprises a pressure. vessel 2l. unner and lower manifolds 2" 9* m'l" mounted within tbe vessel? a corn'oartmpmivpd annular drum 9d rotatably mmmted within the pressure Veqgpl between 97nd in cnmi'vlllrlirlllnn with the manifolds* and .suitable driving mechanisrn for rotating the annular drum.

The pressure vessel 2l is hreterabl fnImPl lll WG Darts. an imber- Flervferl .slaell nr aan 25 and a, lower flanged .shell 2R suitably ioinerl togetber. as lav boltine' to form a eas-ti'rbt ioirit.

The annular drum 24 is xedlv attached as bv means of plates 21. 2R. to a central vertical shaft 29 suitably iournaled in bearings carried bv the upper and lower shell members 25. 2G.

The mechanism for rotating the annular drum is supported on a platform 30 mounted on the upper shell 25 and includes a shaft 3i connected to the upper end of the shaft 29 by a coupling 32 (see Fig. 6). The shaft 3I is driven by suitable reduction gearing mounted in a housing 33, the reduction gearing being belt-driven by a motor 34 (see Fig. 5).

The rotatable annular drum 24 comprises two spaced

concentric cylinders

35, 35, which form the side walls; two spaced annulai`

plates

31, 38,

each secured to the top of the cylinders 35, 36, respectively, form the top of the drum, the space between the

annular plates

31, 38 forming an annular opening 39 in the top of the drum; two

spaced concentric annular plates 40, 4I, each secured to the bottom of the cylinders 35, 36, respectively, form the bottom of the drum, the space between the annular plates 40, 4I forming an annular opening 42 in the bottom of the drum (see Fig. 7).

The rotatable annular drum is divided into a plurality of compartments 43 by radial partitions or dlaphragms 44 (see Fig. 8). In each of the radial compartments 43, near the bottom thereof, there is provided a plate 45 attached to the walls of the compartment, as by welding, to form a gas-tight joint (see Fig. 7). Each plate 45 forms a support for one or more tubular catalyst containers 46. In the particular embodiment shown, only one such container is shown mounted in each compartment.

The catalyst containers 46 are identical in construction and, as shown in Figs. 14 and 15,

each comprises two concentric tubular wire screens 41, 48 held in spaced relation by a plurality of longitudinal radial ns 49. with the annular space between the screens closed at the bottom. The mesh of the screen is such as to retain a granular catalyst material 50 in the annular space between tbe screens. Although the invention is not limited thereto. it is preferred to employ a. catalyst wherein granular silica gel or a substance having substantially the .same structure is the carrier for the active material. OX- ide of copper. nicl-fel, and manganese may be employed as the active material. However. iron oxide is preferred. In connection with the foregoing, `it may be pointed out that the annular beds of catalyst material are so tbin that they permit velocities of about from l0 to 25 feet per minute through the beds at 60-70 F. and atmospheric pressure.

Each ot the containers Mi is closed at its, top by means of concentric boobs 5I. 52 mounted on the concentric screens 41. 48 and a cover plate 53 detachablv connected to the inner hoop 52. as by screw bolts. and having a depending annular trough-shaped flange 54 viitting between the hoops 5|. 52, A depending annular iin 55 is secured to the flange 5!! and proiects downwardly between and below the hoops 5I, 52. and fits in slots 5S formed in the upper ends of tbe radial iins 48, all as shown in Fig. l5. The construction is such that. as tbe catalyst settles down. leaving a space between the top portion of the wire screens devoid of catalysts. the iin 55 will prevent gas from passing through the space devoid of catalyst. Each container 46 is detachably mounted on a nozzle 51 proiecting upwardly from an onening 58 formed in the plate 45. as clearly shown in Fig. '1. The nozzle 51 is secured in the opening 58. as by welding, to form a gas-tight joint.

The top and bottom manifolds 22, 23 are mounted on the top and bottom of the annular drum 24, in communication with the annular openings 39, 42 formed in the top and bottom ofthe drum. The manifolds are identical in construction and each is formed in the shape of an annular trough having an annular top (or bottom) 59 and annular side walls 5l), 6I (see Fig. 9).

A. plurality of compression springs 62, mounted on brackets 63 suitably secured to the inner walls of the vessel 2l, yieldably press the top and bottom manifolds against the top and bottom, respectively, of the annular drumA (see Fig. 7). The

top and bottom-manifolds are-held stationaryrele. ative-to kthe-rotationy ofv the drum bymeans` hereinafter to--be described, and, to prevent the-.ese cape of f gas between; the rotatingl drum and, the manifolds, sealing ring gaskets-f Stare placedat the-junction of the side-walls of` the manifolds and the drum. The sealing ring gaskets 64? are held in tight sealing engagementwiththe top andibottom ofthe-drum by meansof annular hoops 65 which encircle the gaskets and hold them againstthe sidelwallsof the manifold. The upper (or lower) ends ofthe hcops' aresecuredtothe top (or bottomi plate of` themanifold; as by welding. The ring gaskets are retained. between thehoops.l t5' and the side walls` E0, 6;! of the manifolds byvmeans: of a. plurality of circumferu entially spaced. threadedf bolts 66; which engage` the ring gaskets and the lower portions` of the hoops and side walls. Thel ring gaskets Mare yieldably` held in. engagement with the i top and bottom of thedrum 24 by means of a. plurality of4 compression springs ti: mounted on stud bolts 68 secured to the 'top (or bottom) of the` manifolds. and engaging4 annular plates or members- 69 mounted on the topior bottom) of the. ring gaskets, all as clearly shown in Fig. 9.

At three circumferentially spaced points in the top and bottom manifoldsgthere arelocatedseals which, by reason of the sliding contact ofthe radial partitions Ml against the under surface. of the bottoms of theseals, divide the` manifolds and drum into three. sectors, each sector gas-tight withrespectto. the adjacent; sectors.. The seals. are identical in construction and the details thereof; are best shown. in Figs; 9, l0 and 1li. Each seal includes a bottom or `sealing plate it mounted within the manifold between spacedy radial partition walls "Hl, 72. 1i) is yieldably urged against` the top` (or bottom) of the drum and rests on the

concentric plates

31, 38 which form the top of the drum (or plates 4U, 4l which form the bottom of the drum), as shown in Fig; 9. The side edges of the plate 1i! are bifurcated, as shown at 13, 14, for the recep tion of gasket strips 15, 16, which are yieldably pressed outwardly against the partition walls ll,

I2 of the`- seal by leaf springs Tl, '18,t as shown in.

Figs. 1G and l1.

The means for yieldably pressing the bot-- tom plate 'l0 of the seal between the top (or bottom) of the drum comprise a plurality of compression springs i9. mounted. on` projectionsY 80, formed on` the upper surface of the plate 10, The springs '19.u engage the top (or. bottom) of the seal and are held in position by bolts SI projecting through the top (or. bottom) of the seal andv coiled springs and threaded into the projections formed on the plate 10.

Each radial partition or diaphragm 4M has a.

portion of its top. and. bottom edges extending upwardly (or downwardly), between the edges of the openings in the top and bottom of the drum. A, gasket 82' is secured on these portions and exetends above (or below.)` their top (or bottom) edges and engages the under face of the bottom plate'lofthe sealA (seeFg, 11)

Plates 83 areA secured to the tops and bottoms of the partitions andare held spaced therefrom;

by a spacer strip 84, the plates and spacer strip being secured to the partitions by'bolts 85; gaskets 82 are. confined between the partitions and the plates 83, as by means of bolts 86, and are pressed upwardly (or downwardly').Y against the under surface of the bottom plates 1i) of the seals by means of leaf springs' Sli, all as shown in Fig. 11.

The bottom plate Iniiordery; to prevent: the gaskets :82.- from.:` beingJ unduly pressedupwardly:` (orf downwardly) when the1 gaskets: are not"` engaging thebottoms off the seals,v means'l areprovided for spanning the reaches` of themanifolds between the seals:v TheseA means` comprise spaced.'V pairs oftu curvedf`

plates

88, 89 which extend between andare secured tothe partition walls of the seal, as shown in Eig. 12. 83., were. in the same horizontal plane. asithe bottom surfaces of the bottom plates 105.01 the` seals, so` that. as the gaskets 82.move outoffengagement withthe; bottom plate of the seal, they immediately engage the plateslg `89..

A. plurality of rollers 9m areV mountedN within the topand bottom manifolds. These rollers are circumferentially spacedf within the manifolds and.` are; adapted to; engagepthe` annular.` plates- 31.,V 43;. whichform parts of. the. topand bottom. respectively, ofthe rotatable drum;` ThesearollersA are adapted. to prevent frictional surface engage:-

ment: between thesi'de walls of4 the. manifolds and4 the. top and bottomof; the. drum.. Thesarollersz, are;` identical. inV construction and f mounting and; each: comprises: a threaded stud bolt: Sl screwed. into the: outer side: Wall 60 oflxthei manifold; a. balli race;` 9-1J fixedly` mounted. on. thewbolt. and a. wheel 93: mounted. on theA ball` race; allas shown'r iniFig. 13a

Three hanged pipes or conduits `Sill, 95.,` 96 hav.` ing threaded ends, project through the cap of the vessel 2! and have4 their threaded ends secured to. the top. plate of. the top.. manifoldby means. of lock. nuts. 9.1. whichA form. gasftightt secured to` the bottom. plate. of the bottom mani foldby means of locknuts 9T Whichform gas.- tight joints.` Thesel pipes are,` welded to thebotf.- tomof the vessel. 2l.. and. holdl the bottom manifold stationary relative to the rotation` of the'.

drum.` yEhese pipes are circumferentiallyspaced with respect. to thebottom manifold and each. is secured to and communicates with the-manif: fold: at a; point located between the seals. The width ofthe seals withrespecttotheradial com-` partments.; 43 containing the catalyzing units is.

such.. that. at all times at least. one of the par. titions` or diaphragms 44; is engaging the bottom plate 'l0-1 of the seal in gas-tight engagement;

From the foregoing, it will readily: be-seenthat by theengagementrof the radial partitions: with thel seals, the manifolds and drum areV divided into three gas-tight` chambers orV sectors, called, for convenience, the first' reaction` stage, the second reaction stage; andi the activation stage.

The drum carryingi theV tubular catalyst con. tainersisrotated counter-clockwise; as' viewed in Fig. 5', and, as'it rotates; the tubular catalyst containers are successively moved through the threelstagesin the following order: the second reaction' stage,V the firstv reactionstage, and the activation stage.

The now of the gas to be treated, the flow of the oxidant gas, and the now of the regeneration medium are. showrrschematically in Eig. 16a

The sour4 gas toibo tneatecll delivered; underl The bottom surfaces of. the1 plates suitable pressure from a source of supply (not shown), to the lrst pre-heater 6, by means of a pipe line I I. The gas is heated in the pre-heater to an optimum pre-reaction temperature and then passes through a pipe line |92 to the first converter and enters the top manifold of the first reaction stage through pipe 94.

The oxidant gas, preferably SO2, for the first reaction stage of the converter 5, is delivered under suitable pressure, from the sulphur burner I5 through a supply pipe line |93 and a branch valved pipe line lill! connected to the pipe line |02. The mixture of sour gas and SO2 passes downwardly from the upper manifold through the opening in the top of the drum into the various compartments of the drum containing the tubular catalyst containers, as are at that time contained within the sector forming the first reaction stage. The gaseous mixture passes through the pervious layer of catalyst material into the hollow interiors of the tubular containers; thence, downwardly through the opening in the plate 45 into the bottom of the drum, and through the opening therein into the bottom manifold. When the mixture of sour gas and SO2' comes into intimate contact with the catalyst an exothermic reaction takes place in which elemental sulphur is liberated in vapor form, together with steam. in accordance with the following equation:

From the bottom manifold, the treated gaseous admixture passes through pipe 98 and pipe line |05 into the first heat exchanger l, where its temperature, which has risen in the reactor, is adjusted to an optimum pre-reaction temperature. From the rst heat exchanger the gaseous admixture passes through pipe lines |06 and 95 into the top manifold of the second reaction stage of the converter 5.

The oxidant gas, preferably SO2, for the second reaction stage of the converter 5. is delivered under suitable pressure through a branch valved pipe line |91 connecting the supply line |03 and. the pipe line |96. The gaseous admixture moves downwardly through the second reaction stage of the converter 5, in a manner similar to its downward movement through the rst reaction stage and during its passage further reaction takes place, liberating more elemental sulphur vapor and steam.

From the second reaction stage of the first converter 5, the treated gaseous admixture passes through pipe 99 and pipe line |98 into the bottom of the first scrubbing tower 8. The treated gas mixture including the sulphur vapor and steam formed by the reactions in the converter, rise inthe scrubbing tower against a downward flow of molten sulphur, which condenses the sulphur vapor into molten sulphur, which collects in the bottom of the tower.

From the top of the rst scrubbing tower 8, the partially desulphurized gas passes through pipe line |99 into the second pre-heater Ill, where its temperature is adjusted to an optimum prereaction temperature. From the second preheater, the gas passes through pipe line I l!) and pipe 94 of the second converter 9 into the top manifold of the rst reaction stage of the second converter 9.

1 The oxidant gas, preferably SO2, for the rst reaction stage of the converter 9 is delivered under suitable pressure through a branch valved pipe line |I|. connecting the supply line |03 and 8 the pipe line I I0. The gaseous admixture moves downwardly 'through the rst reaction stage of the second converter in a manner similar to its downward movement through the first reaction stage of the rst converter and during its passage further reaction takes place, liberating more elemental sulphur vapor and steam.

From the rst reaction stage of the second converter the treated gaseous admixture passes through pipe 98 and pipe line II2 into the second heat exchanger where its temperature, which has risen in the reactor, is adjusted to an optimum pre-reaction temperature. y

From the second heat exchanger I the treated gaseous admixture passages through pipe line II3 and pipe 95 of the second converter 9 into the top manifold of the second reaction stage of the second converter 9.

The oxidant gas, preferably SO2, for the second reaction stage of the second converter is delivered, under suitable pressure, through a branch valved pipe line ||4 connecting the supply pipe line |93 and the pipe line M3. The gaseous admixture moves downwardly through the second reaction stage of the second converter in a manner similar to its downward movement through the first reaction stage of the rst converter and during its passage further reaction takes place and the remaining elemental sulphur is liberated in vapor form.

From the second reaction stage of the second converter, the treated gaseous admixture passes through pipe 99 of the second converter 9 and pipe line I I5 into the bottom of the second scrubbing tower I2. The treated gaseous admixture, together with the steam and sulphur vapor formed by the reactions in the second converter, rises in the second scrubbing tower against a downward flow of molten sulphur, which condenses the sulphur vapor into molten sulphur which collects in the bottom of the scrubbing tower. From the top of the second scrubbing tower, the now sweet gas passes through a pipe line IIS to its point of use (not shown).

As schematically shown in Fig. 16, air for use as the regenerating medium is forced into the hot air heater I3 by means of the fan or blower I4. The air is heated to a temperature of about 1000 F. in the heater and, from the heater, passes through supply pipe line and branch pipe line IIS to the rst converter 5 and enters the bottom manifold of the activation stage through pipe |90. From the bottom manifold, the hot air passes through the opening in the bottom of the drum into the bottoms of the various compartments of the drum as are at that time contained within the reactor forming the reactivation stage; thence, upwardly through the openings in the plates 5, and up into the hollow interiors of the tubular catalyst containers, through the pervious layers of catalyst material into the compartments of the drum; thence, upwardly through the opening in the top of the drum into the top manifold. As the hot air passes through the catalyst material, any impurities in the form of tars or carbonaceous matter are burned 01T and the catalyst material is reactivated. From the top manifold of the activation stage, the hot air is exhausted to the atmosphere through pipe 96.

I-Iot air for use as the regenerating medium for the reactivation stage of the second converter passes from the air supply pipe IIl and branch pipe line |I9 to the second converter and enters the bottom manifold of the reactivation stage -paratus of -xed size.

:through-pipe 1100 fof fthe `second `converter. u".E'he

hot air :passes "upward through the reactivation stage of the second converter in a mannerfsimilar to its upward passage through the reactivation stage lof 4the grst fconverter sand, during its pasusage, :regenerates `the catalyst material therein.

While the -foregoing description of'thcmet'hod khas not been :concerned with `the utilization rof lance for the differential pressure, a reasonable increasein the over-all-operatingpressures will permit `handling larger gas `volumes in anap- The particular apparatus shown is` designed to. handle gases at #high preszsures; although it is contemplated that the :meth- -od hereindescribed can be `practiced by .utilizing pressures of from :about 5 lbs. to `10.lbs. per square inch.

The presentmethod is contrived to.recover a major portion of the `contained sulphur in the `sourgas in aimultifstage oxidation process without raising the reaction temperature .in any stage kaboveaboutSO" F. by adjustingfthe temperature of the ladmixture of thegas to be treated and the sulphur liberating gas, .illustratively SO2, to an Aoptimum.pre-.reaction temperaturein the range of fromabout 375 F. `to `about 600 F. prior to tions of the contained sulphur may be removed in the respective stages when employing pre- .reaction .temperatures upto about 800 while controlling the reaction 'temperatures in the stages so that they do not exceed about 1000" F. in any stage. It will'be understoody however, that atv higher reaction temperatures than above '830 F., the eili'ciency of the conversion will be reduced. Therefore, -it is highly `preferable Ato vpractice the method at relatively low reaction temperatures.

As a specific example, assume that the .raw gas to betreated contains 125 lbs. of `HzS per 4300 cubic feet .at a pressure of .10V lbs. gauge and at 100" F. Then, about 30% of the initial H2S ,content of the `gas can be converted .into sulphur `vapor in therlrst oxidationstage of the "rst group of reactors by pre-heating the Ygas to about 500 F. and mixing SO2 with the preheated gas at the rate of about 30,1bs. Yof `SO2 per minute prior to the entry of the gas into the reactor in which the rst oxidation stage occurs. The temperature in the reactor wllrise to from about 720 F. to about 750 F.

About of the initial HzS content of the `gas Ican be converted into sulphur `vaporin the second oxidation stage of the rst group of re- .actors by cooling the` gaseous admixturc delivered from the iirst oxidation stage to about 500 F., then mixing SO2 with the cooled gaseous mixture at the rate of about 30 lbs. ofSOz per minute prior to its entry into the reactor in which the second oxidation stage occurs. The temperature in the reactor will rise to from about-680 F. to about '710 `F.

About 30% of the initial total I-IzS content of the gas can be converted into sulphurvapor in the first oxidation stageof thesecondgroup of reactors by pre-heating thegas after-its pas usage `through the .rst scrubbing-tower :to about :500 iF. :and Lmixing .SO2 `with the pre-.heated gas .at the rate rofl-about 430 A.-lbs. of SO2 per .-minute .prior ito :its entry into :the reactor in `the 4secondigroup :of `reactors `in which -the *rst 5 oxidation :stage occurs. Thetemperature 'in the :reactoriwilllrise to from -iaboutf670 F. :to .about 700 F. The remaining 1.0% Aof the initial total A'I-IzS content of the gas :can Abe `converted into sulphur vapor Yin 'the second oxidation stage l:of

41() the Asecond group .of reactors :by cooling .the

gaseous fadmixture ldelivered from the rst oxidation-stage to about r50.0 F., .thenmixing .SO2 lwith fthe fcooled gaseous Aadmixture -at the rate of about `1.1 ,lbsnof `SO2 per minute prior to :its entry into fthe reactor of the second group fof .reactors in which .thesecond ,oxidationfstage occurs. The temperature .inl `the reactor will rise to from about 530 F. toabout ,560

Obviously, with a `raw ,gas vhaving sa imuch 420 lesseixHpgS content, it willbepossible .to remove @all of the H28 in V.the first group of reactors :zwithout raising lthe .temperature in .either :the

lrst vor :second .oxidation stages above a `permissble reaction temperature of l,from about .25 747 F. to about 830 F.

It is `always advisable,r however, ito do `fas-much :oxidation .as 'possible in `the first :.stage, consistent .with the above'fmentioned reaction item- ;peratures, so that :it has been found` advisable, fwhen .treating a :.gas :containing Yabout 315% .HzS, `to vsupply oxidant gases :to :the `various .stages so as to accomplish zabout 955% :conver- :sionn the rstlstagarabout .25% .inthe second stage, :about 412% .in the third fstage, and8% in `.the last stage. Since, Ainthevearler stages, .the catalytic conversion can not be "completed, :the reaction `inthese stages-.can be assisted .by `.thepresence of an .excess of ioxi'dantgas. Thus, ..to .accomplish `the .illustrative :reactions above, `it thas been found .convenient `to supply :about '7.5% fof thefltotal oxidanttgasin `therirst stage and 'the :remaining ^"25% `in the :second astage. Thexexcess notzused'upmreither of these .stages is .carried "with "the gas :to be treated, `andiis y `available as needed-lin the lastctwowstages.

In connection with the foregoing, aitimaysbe lpointed outfthat, "as the .boiling ,point of .sulphur -1is 1832 F a `pure sulphur vapor wouldcondense Ito liquid Aif cooled .below fthatltemperature. `;In

`the present method, fas :abovedescribed, there 50. is ino concentratedsulphur vat any point. In fact, -the maximum concentration isabout 2%, at which concentration the -sulphur vapor Will -remain in `vapor form atfthepressures anditemper-atures employed `in thefprocess.

While .it :is :not a necessary feature fof the invention, it may be pointedout that, -if the liberated sulphur content .of `the treated 3 gas `becomes too high between the rst andsecond oxidation stages of `either group of reactors, :all `,or part "of .itlma'y be removed. This `is Vreadily accomplished, fior example, by suitable adjust- .ment .of lthe .heat exchangers 7 `land .fl'|.

`The scrubbing i towers Vii .and `l2 may `be of any suitable `usual type. In the :particular embodiment illustrated, molten `sulphur is withrdrawn from thefbottomof the` scrubbing tower -8 through ipipe line `V20 bypump [2| ,and `deliveredtofa `sulphurcooler .|22 through apipe 7oline 123. From the sulphur 'cooler 122, the molten sulphur passes throughgpipe line |124 to thevtop `of the scrubbing tower 8. :The `molten `sulphur cascades downwardly through thescrubbing ,tower and iscbrought :into intimate lcontact with the counter-current r stream Aof .-gas, `:steam fr and elemental sulphur vapor rising through the scrubbing tower and condenses the sulphur vapor into vmolten sulphur which collects in the bottom of the tower. In like manner, molten sulphur is withdrawn from the bottom of the scrubbing tower |2 through a pipe line |25 by a pump |26 and delivered to a sulphur cooler |21 through a pipe line |28. From the sulphur cooler |21, the molten sulphur passes through a pipe line |29 to the top of the scrubbing tower |22 and cascades downwardly through the tower in counter-current to the upward flow of gas,

steamand sulphur vapor therein and condenses f the sulphur vapor, which collects in the bottom of the tower. A portion of the molten sulphur being recirculated through -the two scrubbing towers, is withdrawn through a, pipe line |30, which is connected to a cross pipe line |3| connecting the discharge pipe lines |24 and |28 from the sulphur coolers |22 and |21, and delivered in its molten state to a sulphur cooling and flaking machine (not shown). Pipe line l1, through which liquid sulphur is supplied to the sulphur burner I5, is shown as being connected to pipe line |30.

By mounting the annular drum and the manifolds of the converter within pressure vessels, the method may be carried out with highV pressure gases and, too, the equalization of pressure within the drums, manifolds and vessels, permits the drums and manifolds to be made of lighter weight material, which adds considerably to the efcient and economical operation of the converters. This equalization is accomplished by means of a small opening |32 formed in that portion of the pipe line 94 within the vessels 2|. It is also considered desirable to provide each of the six

pipes

94, 05, 96, 98, 99 and of each of the converters with expansion joints |33, located a short distance from their points of connection to the manifolds. This may be necessary, due to the unequal temperatures of the gases and media as they pass through the various sectors, thereby resulting in unequal. expansion of the parts of the drums and manifolds.

. While two three stage rotary converters have beenrshown, obviously, one converter may be used, if desired, in which case, the treated gas,

Y after passing through the first scrubbing tower y 8, would be sent to its further point of use by means of a valved by pass conduit |34 connected to valved conduit |09.

From the foregoing, it readily will be seen that there has been provided a novel method of recovering elemental sulphur in liquid form from gases containing HzS, which provides for carrying out the reaction process in at least two oxidation stages with control of the temperature rise in each stage, thereby permitting the reaction process to be effected at temperatures below about 800 F., with resulting increase in efficiency of the process, use of less expensive apparatus, and permitting the use of a catalyst carrier such as silica gel.

While the invention has been described in connection with the desulphurization of sour gas, obviously, it is also applicable to the desulphurization of other types of sulphur-containing gases and vapors which are subject to the action of a suitable catalyst.

Obviously, the invention is not restricted to the particular embodiment thereof herein shown and described. Moreover, it is not indispensable that all of the features of the invention be used l2 conjointly, since they may be employed advantageously in various combinations and subcombinations.

What is claimed is:

l. In the recovery of elemental sulphur in liquid form from gases containing H2S involving the contact of a catalyst with the gas containing HzS to form sulphur vapor and the subsequent treatment of the catalyst in an oxidizing atmosphere to regenerate the catalyst for further contact with the gases containing HzS and the subsequent condensation of the sulphur vapor to form liquid sulphur, the improvement which comprises rotating a series of separated thin beds of catalyst directly and in succession and substantially continuously relative to and through a series of reaction zones and a regenerating zone; continuously directing the flow of the gas to be treated in succession and in series through said reaction zones; subjecting the gas to be treated to heat exchange to bring its temperature to an optimum reaction temperature and mixing a predetermined amount of oxidant with it prior to its passage through each of the reaction zones to convert a portion of the H2S in each of said zones into sulphur vapor and steam; continuously withdrawing the treated gas from the last one of the reaction Vzones and directing its flow through a condensing zone and there condensing the sulphur vapor to form liquid sulphur; and continuously directing the ow of a hot oxidizing medium through the regenerating zone to reactivate the catalyst therein.

2. The method, as set forth in claim l, wherein the direction of the series flow of the treated gas is opposite to the direction of rotation of the catalyst beds, whereby the treated gas will alway-s make its last passage through freshly activated catalyst beds.

3. The method, as set forth in claim l, including rotating a second series of separated thin beds of catalyst directly and in succession and substantially continuously relative to and through a second series of reaction zones and a regenerating zone; continuously withdrawing the treated gas from said condensing zone and directing the flow of the withdrawn gas in succession Vand in series through said second succession of reaction zones; subjecting the withdrawn gas to heat exchange to bring its temperature to an optimum reaction temperature and mixing a predetermined amount of oxidant gas with it prior to its passage through each of said second series of reaction zones to convert a portion of the HzS in each of said second series of reaction zones into sulphur vapor and steam; continuously withdrawing the treated gas from the last one of the reaction zones of said second succession of reaction zones and directing its flow through a second condensing zone and there condensing the sulphur vapor to form liquid sulphur; and continuously directing the flow of a hot oxidizing medium through the regenerating zone of said second succession of zones to reactivate the catalyst therein.

4. The method, as set forth in claim l, including the step of burning a mixture of sulphur and air to make SO2 and supplying the SO2 for use as the oxidant.

5. In the recovery of elemental sulphur in liquid form from gases containing I-IzS involving the contact of a catalyst with the gas containing HzS to form sulphur Vapor, the subsequent treatment of the catalyst in an oxidizing atmosphere to regenerate the catalyst for furt-her contact with the gas containing I-IzS and thesubsequent condensation of the sulphur vapor to form liquid sulphur, the improvement which comprises rotating a series of beds of catalyst directly and in succession and substantially continuously relative to and through a series of reaction Zones and aV regenerating zone; continuously directing the flow of the gas to be treated in succession and in series through said reaction zones; subjecting the gas -to be treated to heat exchange to bring its temperature to an optimum reaction temperature and mixing With the gas to be treated an amount of SO2 suilicient to convert a portion of the HzS into sulphur vapor and steam, Without raising the temperature of reaction in any of the zones above about 800 F. prior to its passage through each of the reaction zones; continuously withdrawing the treated gas from the last one of said reaction zones and directing its ow through a condensing zone and there condensing the sulphur vapor to form liquid sulphur; and continuously directing the flow of a hot oxidizing medium through the regenerating zone to reactivate the catalyst therein.

6. The method, as set forth in claim 5, including rotating a second series of separated thin bed-s of catalyst directly and in succession and substantially continuously relative to and through a second series of reaction zones and a regenerating zone; continuously withdrawing the treated gas from said condensing zone and directing the flow of the withdrawn gas in succession and in series through said second succession of reaction zones; subjecting the gas to be treated to heat exchange to bring its temperature to an optimum reaction temperature and mixing with the gas to be treated an amount of SO2 suilcient to convert a portion of the HzS into sulphur vapor and steam without raising the temperature of reaction in any of the zones above 800 F. prior to its passage through each of the reaction zones; continuously withdrawing the treated gas from the last one of the reaction zones of said second succession of reaction zones and directing its flow through a second condensing zone and there condensing the sulphur vapor to form liquid sulphur; and continuously directing the flow of a hot oxidizing medium through the regenerating zone of said second succession of Zones to reactivate the catalyst therein.

7. The method, as set forth in claim 5, including the step of withdrawing a portion of the liquid sulphur from the condensing zone and burning it to supply the SO2.

tion zone and a regenerating zone; mixing a predetermined amount of the gas to be treated with a predetermined proportion of sulphur-liberating gas and continuously directing a flow of the mixed gases at an optimum pre-reaction temperature through said reaction zone to convert the HzS in said reaction zone into sulphur vapor and steam; continuously withdrawing the treated gas mixture from said reaction zone and directing its ow through a condensing zone and there condensing the sulphur vapor to form liquid sulphur; and continuously directing the flow of a hot oxidizing medium through the regenerating zone to reactivate the catalyst therein.

9. The method, as set for-th in claim 8, including the step of burning a mixture of sulphur and air to make SO2 and supplying the SO2 for use as the oxidant.

10. The method as set forth in claim 9, in which the sulphur is obtained by recycling a portion of the recovered liquid sulphur.

ERNEST B. MILLER.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,773,294 Benner Aug. 19, 1930 1,922,872 Thompson Aug. 15, 1933 2,298,641 Schulze et al s Oct. 13, 1942 2,384,926 Jones Sept. 18, 1945 2,388,259 Fleming et al. Nov. 6, 1945 2,497,095 Nevins et a1. Feb. 14, 1950 2,561,990 Miller July 24, 1951 FOREIGN PATENTS Number Country Date 120,554 Great Britain Sept. 25, 1918 (Complete not accepted; application date cited) 267,138 Great Britain Dec. 15, 1927

Claims

1. IN THE RECOVERY OF ELEMENTAL SULPHUR IN LIQUID FORM FROM GASES CONTAINING H2S INVOLVING THE CONTACT OF A CATALYST WITH THE GAS CONTAINING H2S TO FORM SULPHUR VAPOR AND THE SUBSEQUENT TREATMENT OF THE CATALYST IN AN OXIDIZING ATMOSPHERE TO REGENERATE THE CATALYST FOR FURTHER CONTACT WITH THE GASES CONTAINING H2S AND THE SUBSEQUENT CONDENSATION OF THE SULPHUR VAPOR TO FORM LIQUID SULPHUR, THE IMPROVEMENT WHICH COMPRISES ROTATING A SERIES OF SEPARATED THIN BEDS OF CATALYST DIRECTLY AND IN SUCCESSION AND SUBSTANTIALLY CONTINUOUSLY RELATIVE TO AND THROUGH A SERIES OF REACTION ZONES AND A REGENERATING ZONE; CONTINUOUSLY DIRECTING THE FLOW OF THE GAS TO BE TREATED IN SUCCESSION AND IN SERIES THROUGH SAID REACTION ZONES; SUBJECTING THE GAS TO BE TREATED TO HEAT EXCHANGE TO BRING ITS TEMPERATURE TO AN OPTIMUM REACTION TEMPERATURE AND MIXING A PREDETERMINED AMOUNT OF OXIDANT WITH IT PRIOR TO ITS PASSAGE THROUGH EACH OF THE REACTION ZONES TO CONVERT A PORTION OF THE H2S IN EACH OF SAID ZONES INTO SULPHUR VAPOR AND STEAM; CONTINUOUSLY WITHDRAWING THE TREATED GAS FROM THE LAST ONE OF THE REACTION ZONES AND DIRECTING ITS FLOW THROUGH A CONDENSING ZONE AND THERE CONDENSING THE SULPHUR VAPOR TO FORM LIQUID SULPHUR; AND CONTINUOUSLY DIRECTING THE FLOW OF A HOT OXIDIZING MEDIUM THROUGH THE REGENERATING ZONE TO REACTIVATE THE CATALYST THEREIN.