DE2658327A1 - CATALYTIC PROCESS FOR THE REMOVAL OF SULFUR DIOXIDE FROM GASES - Google Patents

Description

GTE! Laboratories Incorporated, Wilmington, Delaware, USA

Catalytic decay to remove sulfur dioxide from gases

Priority: December 24, 1975 - USA - Serial No. 642 622

The invention relates to the removal of sulfur dioxide from gases containing this, in particular the catalytic Reduction of sulfur dioxide with a reducing gas, preferably carbon monoxide, to elemental sulfur in gases containing sulfur dioxide, such as combustion or furnace gases, gases derived from the gasification of oil or coal, gases containing sulfur dioxide, Hlitten gases etc.

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Sulfur dioxide is a component of many exhaust gases, such as steel mill gases, combustion gases, exhaust gases from coal and oil-burning stoves and boilers. The pollution or pollution of the atmosphere with sulfur dioxide, whether in low concentrations of 0.05 to 0.3 percent by volume, as in combustion gases from power plants or in larger quantities of 5 to 10 % _t as in roasted ore gases, was a health hazard for many years Touching public problem due to its irritating effect on the respiratory system, its harmful influence on plant development and its corrosive attack on many metals, textiles and building materials. Millions of tons of sulfur dioxide are emitted into the atmosphere each year in the United States from the burning of fuel or heating oil and coal; a larger amount of such sulfur dioxide is produced during the generation of electrical power.

Since lowering the sulfur dioxide content of blast furnace gases is key to generating usable energy from the abundant fuels (coal and high sulfur oil) in an environmentally acceptable manner is there have been many methods for removing sulfur dioxide from such gases are proposed and are currently being investigated. In the United States it is currently estimated investigated about 50 methods for removing sulfur dioxide. While the procedure is technically feasible appear, the cost of sulfur dioxide removal is significant. To some of the more common procedures includes washing the furnace gas in trickle towers (scrubbing) and precipitating the sulfur dioxide with lime as calcium sulfite or after oxidation as calcium sulphate. The washing of the very large amounts of exhaust gas as well as the collection and disposal solid precipitation from the washing liquid is costly.

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An inherently less expensive method of removing sulfur dioxide relies on its catalytic reduction with carbon monoxide or another reducing agent. This method does not require washing a gas with a liquid or separating a pesticide from the liquid. This method has been tried with a wide variety of catalysts, but to the best of our knowledge, such methods present one or more of the three main difficulties. First, burners, as they are in operation to generate electrical energy, work with fuel mixtures with excess air or "fuel-poor mixtures". This is done to avoid the formation of explosive carbon dust and to get more energy from the fuel. As a result of using the fuel lean mixture, the furnace gas is rich in oxygen. This oxygen poisons many of the catalysts tested in the "past, destroying their catalytic activity and lowering the overall efficiency of the reduction process. Second, certain of the catalysts used catalyzed the reduction of water by carbon monoxide to form carbon dioxide and hydrogen, or they catalyzed the reaction of water and sulfur to hydrogen sulfide and oxygen. Viasserstoff reacts with sulfur to form hydrogen sulfide, at temperatures down to about 200 ⁰ C, and so in any case, the sulfur dioxide is converted to another toxic material. Thirdly catalyzed certain of the non-specific catalysts of the oxidation of Carbon monoxide from sulfur to form carbon oxysulfide, another highly toxic gas These difficulties arise from the non-specific nature of the catalytic material.

The invention is therefore primarily intended to provide a new method for removing sulfur dioxide therefrom

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Specify gas flows, in particular a method for the catalytic reduction of sulfur dioxide to elemental sulfur. It is intended to provide a process for the catalytic reduction of sulfur dioxide in gases containing it to elemental sulfur using special catalytic agents which are not subject to poisoning by oxygen or water and which suffer less from the deficiencies mentioned above. Finally, the invention seeks to provide a process for the catalytic reduction of sulfur dioxide by a reducing gas to elemental sulfur which is specific enough to work with lean fuel mixtures, the environmentally acceptable fourth being sulfur dioxide, hydrogen sulfide or carbon oxysulfide. In the course of a catalytic reaction, hydrogen sulfide or carbon oxysulfide and sulfur dioxide should form elemental sulfur using special catalytic materials that are not poisoned by oxygen. Finally, the invention is intended to offer new catalytic compositions which are suitable for use in the process according to the invention.

Further objects, advantages and features of the invention will emerge from the more detailed description below.

The solution according to the invention consists in the use of an agent or a composition of the formula XLa ₂ O ^ · yCo "0 in which χ and y can be varied independently of one another from 1 to 3 inclusive (including non-integers) as a catalyst in the catalytic reduction of Sulfur dioxide with a reducing gas, such as hydrogen or preferably carbon monoxide, in gas streams containing sulfur dioxide to form elemental sulfur. The values given above for χ and y are the ratio of the oxides to one another

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other, not to be understood as absolute values.

LaCoO-z, which has a perovskite structure, is a well known one Redox catalyst that has been used for the reduction of cis-2-butene in the presence of hydrogen (see Libby, SCIENCE, vol. 171, pp. 499-500, February 5, 1971; Pedersen and Libby, SCIENCE, vol. 176, pp. 1355-1356, June 23, 1972), as well as for the oxidation of carbon monoxide in the presence of oxygen to carbon dioxide (cf.Voorhoeve et al, SCIENCE, Vol. 177, pp. 353-354, July 28, 1972). In each of the publications mentioned, it was suggested that LaCoO, to test as a possible car catalytic converter. To the best of our knowledge, however, LaCoO has never been suggested as a use catalytic material for the reduction of sulfur dioxide to elemental sulfur, where a reducing Gas, such as carbon monoxide, is added to the gas stream containing sulfur dioxide. In fact, it has been reported that LaCoO., is poisoned by sulfur dioxide when LaCoO., used as a catalyst for the conversion of CO to COp see Yung-Fang Yu Yao "The Oxidation of Hydrocarbons and CO over Metal Oxides, IV. Perovskite-Type Oxides, "a publication presented at the 76th Annual Meeting of the American Ceramic Society, Paper No. 41 E 74, April 30, 1974, Chicago, Illinois. Next was after Previous knowledge never suggested the above catalytic materials as the catalytic material to remove sulfur dioxide in a reaction of the Claus type or to reduce the COS concentration to be used via the reaction with sulfur dioxide, as set out below.

Although LaCoO., Is a known catalytic material and corresponds to a composition of xLa ^ O, «yCopO, where χ = y, the other catalytic compositions (ie, where χ ± y) are so far to be regarded as new. Such

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can be used as iaCoCjL. — Ehase ΐτπ combination with one

© of the several phases of excess Ia ₂ ⁰ ^ ™ £ l / or of oxides iron cobalt and / or other unidentified Hiaterla.1 fen. It should be noted that the xolbalt oxide used in the manufacture of these materials is in fact a mixture of colbalt oxides, but this cobalt oxide of a grade suitable for the reaction has a koibalt analysis corresponding to 101 % Co "0"; In this section, colloidal oxide is regarded as COpO-r. Experiments with such preparations have shown that the catalytic activity compares favorably with IaCoO ^, inanlly prejudiced by the presence of excess J & JQ-x or carbon oxides. This was surprising and completely unexpected, since preparations in which χ = 0 (Go ₂ O-) and y = 0 (la ^ O. As for the Yorliegens the excess ii & .Jß ^ or Kobaltoxidphasen (the lower kataljtische Iktivität "have) an ^M ¥ erdÜTQnii] ing ^M of the catalytic activity wiarde expected is actually found for the JMischphasenpräparate comparable kataljtische activity in the idaT as surprising AmzMsehen. It is assumed that these I ^v Iischphasenpräparate as such are nem, it also follows that they have not previously been proposed as catalysts for the Eediaktion of sulfur dioxide aa elementary sehuufel, especially where a reducing gas, such as For example, carbon monoxide is set or is present in sufficient quantities in gas streams containing sulfur dioxide, nor can they have been used in the catalytic reaction of hydrogen sulfide or carbon oxysulfide with sulfur dioxide with the formation of elemental sulfur in the absence or in the presence of oxygen.

Sbenfaüs In the JSshaen the usable iatalytic materials

are the derivatives of the materials of the above formula, as they are obtained by (a) pre-reduction with carbon monoxide or hydrogen (see below), (b) contact with the starting or subsequent gas streams supplied (e.g. in a first or second etc. catalytic converter ) or (c) by pre-reduction by carbon monoxide or hydrogen and contact with the respective supplied streams. Proven derivatives include CoS ₇ . (such as Co. S. ,, CoS ₂ , Co-S, and Co ₀ Sg), La ₂ O ₃ S _x (such as La ₂ O ₂ S and La ₂ O ₂ S, La ₂ O ₂ SO. and La ₂ CoO ,, mainly CoS ₂ and La ₂ O ₂ S. These derivatives can be added as mixtures, such as a mixture of CoS ₂ and La ₂ O ₂ S (for example in a CoS ₂ : La ₂ O ₂ S-MoI ratio of about 2: 1) or as a preformed material of the formula XLa ₂ O-. yCOgO ,, as indicated above. So far it does not appear that the individual derivatives are useful catalytic materials. For example, CoS, used alone, sinters rapidly with the prevailing ones high temperatures and also leads to the formation of excess carbon oxysulphide. The 1 ^ ₂ O ₂ ³ X does not have the desired selectivity or performance. However, the catalytic material is preferably preformed, since a more uniform distribution of the lanthanum oxide and the cobalt oxides or their derivatives with one another is obtained, and this seems to enhance the desired catalytic activity and thereby prevent over moderate sintering and subsequent deactivation of the catalyst.

From the broadest point of view, the process of the invention is directed to the removal of sulfur dioxide from any gas stream containing it, using the catalyst defined above and adding a reducing gas, such as hydrogen or preferably carbon monoxide, or in sufficient amounts in sulfur dioxide containing Gas flow within the range of about + 15 % _t generally about + 10 56 that for the

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complete reduction of all sulfur dioxide present to elemental sulfur required stoichiometrically Amount is present. If the amount of reducing gas in the stream is sufficient, there is no need to add any more narrow gas v / earth. However, narrow of the reducing gas can be added or generated in situ as needed to provide the desired amount of reducing agents relative to oxidizing agents to deliver in the gas stream.

The first and currently most "considered" aspect of the invention is a process based on the removal of sulfur dioxide from combustion or furnace gases containing it, particularly those derived from coal, oil burning processes, or any other process containing sulfur dioxide Of particular interest is the particularly serious case of a furnace gas which originates from coal combustion and contains plug ash (to an extent not removed by separation) and generally a composition of about 0.32 % SO ₂ , 3.2 % O ₂ , 15 % CO ₂ , 7.6 % H ₂ O, 0.12 % nitric oxide, the remainder nitrogen, ie in which the 0 ₂ / S0 ₂ ratio is about 10: 1 and the water content is very high (which could lead to the formation of H ₂ S) to which about 7.2 % CO is added. Since the remaining fly ash and other components (including oxygen) of the gas stream do not "poison" the catalytic material of this process, it is effective for the desired removal of sulfur dioxide. The catalyst works even better with gas streams that originate from oil combustion, in which the 0 ₂ / S0 ₂ ratio is more favorable and the fly ash content is much lower.

According to a further aspect of the invention, the inventive Process considered applicable to other uses where the gas stream has a higher SOp content and a

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has a lower O ₅ , content, such as "in gas streams from ore rusting, to colile processing plants in which KoMLe is converted into gas and / or oil, or in scrubber systems in which absorbed sulphide is oxidized to SOj, by a concentrated gas stream containing SOp, etc. Typical gas concentrations considered here were about 3-20 % SO ₂ , 1-5 5a O ₂ , a few percent Hg ©, remainder U ₂ , Bas SO ₂ in such a gas stream As taught here, catalytically reduced to elemental sulfur with the addition of a reducing agent, and about even substantial amounts of HpS formed could be recycled through a scrubber, or the product stream can be sent to a second catalytic reactor after removal of the sulfur 221, which is loaded with xLa "© _x - yC ©" © · *, where unconverted SO "and remaining HpS are catalytically converted to elemental sulfur. Such ILS formation would not be forbidden, since d it would remove most of the high concentration of sulfur dioxide from the gas stream.

The reduction to elemental sulfur "takes place among other things according to the known reactions:

^S0 2

^S0 2 ⁺ ^ latai ¹¹ / ^2NO 2 ^{+ m} 2 ° (II)

Other forms of sulfur, as ζ "Β S ₁₂ - or S ₀ -can formed · The important considerations in such Brozessen refer to the reduction (and continuous reduction) of the sulfur dioxide, although oxygen, nitrogen oxides and other reducible components are present , on the possible reduction of iron sulfur dioxide to sulfur

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hydrogen in the presence of water, the possible reduction to carbon oxysulphide by direct reaction between carbon monoxide and the sulfur dioxide and the formation of hydrogen sulphide and carbon oxysulphide by reaction of the gaseous sulfur, as it is obtained in the main reduction stage, with other components present in the gas stream. In experiments previously carried out with gas streams having high SOp contents, or in which carbon monoxide was added to increase its concentration to no more than the stoichiometric amount required to reduce all of the oxygen and sulfur present this carbon monoxide was generated in situ, it was found that the reduction of oxygen is favored over the reduction of sulfur dioxide (in the presence of oxygen), but the reduction of sulfur dioxide is not excluded while oxygen is present; may, in the presence or absence of oxygen practically complete reduction of the sulfur dioxide to elemental sulfur at temperatures below 700 ⁰ C, generally between 450 and 65O ⁰ C take place; the presence of water at the elevated reaction temperatures does not result in the formation of unacceptable amounts of hydrogen sulfide; and carbon oxysulfide is not formed in substantial amounts in the reduction process (unless the feed gas contains carbon monoxide in concentrations above the stoichiometric amount required to reduce all of the oxygen and sulfur dioxide). In addition, the formation of carbon oxysulphide is further inhibited in the presence of water. Therefore, the method according to the invention provides, as it relates to gas flows with high SOp content, significant advantages over previously known methods, in a single stage (although a plurality of stages are contemplated), at a necessary temperature of less than 700 ⁰ C, the sulfur dioxide into elemental sulfur in the event of a

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gaseous reaction mixture to give the appropriate, (© the desired) stoichiometric balance between the reducing gas and the Selswefeldiffixid (Taint other reducing substances). An extreme excess of EOMLemmornoxid (ie more than 10 % above the stoemiometry required amount) should be avoided, as this leads to the inevitable formation of carbon oxysulphide.

Shore sulfur dioxide / reducing gas degassing gas stream is with the catalyst according to the invention; accommodated in the buckets first Eaaarweriter in contact, in the converting the sulfur dioxide in the elemental sulfur and the Eciljileii! H © m © xid wn EalEleiiuäi & dioxide oxidizes and / or hydrogen to water © is xydiert "The formed elemental gaseous Sctewefel TKixdl (iaiEEL · aits The gas flow is affected by the gas flow when the ase cools down the Wmmmäl u-trigsleistimg of Irbeitssystems further erinSkem m "," Werfalireiisparameter, building materials and kind mai AlimessTsimg the n5tig © m apportionment köraieB. rerfaliiremsteelmischen using solGEfeer clneniiseJiem turnd ■ ^ principles bestiearfc werdem as they are well known in düesem SeBiet.

Her Eataulysator is preferred with EohlenrniaiueiiXid. or water staff _% "carbon dioxide is preferred, at about 5% Ms" 700 ⁰ G, in the average 7QO ⁰ G »for about 15-45 mm ^ in general. about 3® BTT τη _g lei the desired flow rate <j £ iBwiiEdigfcei.tem ^ © m Stiekstaff wan. Carbon monoxide or hydrogen "foelnam <äelt, Bieser lievarztEgte ^ step of the Eatalysatar local vmäL place in the catalytic reactor or to the core) <inarcm-

we can and generally armcm (jMgebgeffiTfrnrt fulfilled, as was found, the Seliarefelemtfermitmgs-

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performance of the catalyst to the desired maximum before the point in time when it first started containing the sulfur dioxide Gas flow comes into contact. This ensures the highest possible sulfur dioxide removal performance, even during the first few hours of contact, whereas without such a pre-reduction stage a defined one Period of time is on the order of minutes or hours, depending on the material that the material is reaches its maximum removal performance for given operating conditions. So the pre-reduction stage is desirable, to ensure maximum removal of sulfur dioxide at all times.

Satisfactory conversion rates have been achieved at space velocities through the catalytic reactor (s) in the On the order of 2,000-36,000 gas volumes / catalyst volume / h achieved, albeit both higher and lower Space velocities depending on the composition of the gas stream come into consideration.

A particular advantage of the catalyst according to the invention and the process is that after a temperature cycle from the desired operating temperature to a lower temperature with a subsequent return to the desired one Operating temperature, the catalytic conversion practically reverts to the original conversion rate. Hence it will, if there is an emergency shutdown of the system or the catalytic reactor or the catalytic reactors or another lowering of the temperature of the catalytic reactor (s) takes place, not necessary, the catalytic one Replace material. Instead, when the catalytic reactors are ready, they can be switched back to the desired operating temperature can be brought, and the catalytic Material works practically as well as before

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to the"

Μβτ «¥ ir" T "5 TnüTiinpigage iiTsä IB «? Catalyst Uramin naeli known üecla- nüfcen can be pelletized, such as doreM production of an aqueous on, wtnihi äimwninriigj duareh pouring in the form of a thin had C5jH © irrm thickness} on buckets imeirteia. Ma "fce3? Ial _f laaclafOlgenfles" üicoeltaieii mild. Sinifceiai t »egg earSiolateinL TeMpeira— inareii. The sintered steel is then turned into pellets

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eriiaadioEigsgeiiäiBe Eatalysatoip Sranaa aaacSa. Ijeisoaiiteii Tech— mUcem aacb. buckets of slant to cool, me ζ · Β · ömtcIi üeprägnierem a suitable erageno material with its aqueous solution and subsequent treatment and firing of the embossed Materials.

On the other hand, the fimgenmaterial fowrc in a suitable manner according to l ^ eljsnnteii Ττ ^ τϊ ^ γ ^ τπ ü νψτΏ ^ ρ ü ipir iiimg Hifc ^^ tinn) ϊ ifcgw be loaded with dea catalyst. Suitable 'Erägerereialien are for example ^! irfconosid ", lüioroxid, magnesium oxide, i 1 τηπππτιτηüiraimm-ar-f jj | ₃

- ^ "Πτ ηπιηϋτπιϋτηΜί-awrfd mnd the like., In particular soleli3 with surfaces, lacto. The catalyst ^ ragnieriiing nat der Kataljsat © r / Trager menr aifctxve places per Tolaameneinlaeit, which the JRedmüfction ύζμι S ^: ii.weield

In the case of a detailed procedure, the primary materials are sieved with 0.59 Ms 0.25 µm (-3O / -4-SO Mesm) and with aqueous solutions of calcium and sodium nitrate © of the other salts, such as acetates, © xalates and carbonates, impregnated, after the firing a sirager target impregnated with about 5.5 S® Iac © © - * In a further example - 3aafifcem working method non-metalized iron oxide particles or xittrium ioscid stabilized zirconoside He hit cobalt tar rates for the production of aqueous Sns.

pensioneia. geaaiisciite BdLe Suspeaasioneia are zn pellets of

Extruded 3.18 mm diameter, and then dried at temperatures between about 900 ⁰ C and 1100 ⁰ C, preferably about 900 to about 1000 ⁰ C, fired to fired pellets having a composition of 5 weight percent Henn LaCoO yield. Auxiliaries such as binders, for example camphor, lubricants or lubricants and wetting agents, etc., can be added to the suspension to improve the extrusion or the pellet molding process.

High surface area lanthanum cobalt oxide was produced using the freeze drying technique. In this procedure a stoichiometric mixture of solutions of soluble salts of lanthanum and cobalt is frozen for removal of the water evaporates and forms lanthanum and cobalt oxides decomposed in a vacuum. This mixture can then be fired in air to form the desired material will. Similar techniques have been used to produce lanthanum-cobalt oxides in zirconia as supports.

Since the pressure drop through a pellet-type fixed catalyst bed can be high and therefore the running costs of a Increased catalytic reactor, honeycomb structures, such as cordierite honeycomb, can be used as a support for the catalytic Material according to the invention is used because the pressure drops through it are usually lower than at Pe11et structures.

The only figure is a schematic flow sheet for the Desulfurization of exhaust gases from a coal-burning power plant according to the invention.

The figure shows a main power plant 10 in which High sulfur fuel is burned in the presence of air. A high temperature ash separator 12, e.g. an electrostatic precipitator, and more if necessary

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Filter means 14 are used to remove as much of the particulate matter from the exhaust gas stream as possible (preferably everything). If the combustion gases contain more hydrogen than is considered desirable, may a sacrificial catalyst can be used in the catalytic reactor 16 to remove such hydrogen to the subsequent To prevent (or at least limit) the formation of hydrogen sulphide. A carbon monoxide generator 18, such as a gasifier for coal or oil, of the order of magnitude about 10> o the capacity of the main power plant 10 is used to supply the carbon monoxide required to reduce the sulfur dioxide and oxygen used. The generator 10 is connected via a line 20 to the combustion gas stream 22, which consists of the catalytic Reactor 16 exits or, if the reactor 16 is superfluous, with the combustion gas stream that emerges from the Filter device 14 exits. The catalytic reactor containing the catalytic material of the present invention can be constructed in one or more stages, if cooling is required in intermediate stages or where a second stage is required to ensure the overall performance of the desulfurization process to improve. As shown enters the combustion gas stream 24, the sulfur dioxide, oxygen and carbon monoxide contains, into the interstage cooler 26 and flows in countercurrent to the gas flow from the catalytic reactor 28 of the first stage exits. After the gas flow has passed the cooler 26, the catalytic reactor 28 and then again the Has passed cooler 26, the sulfur formed in the reactor 28 (as at 30) is removed from the flow system, before the gas stream enters the second stage catalytic reactor 32. Since the carbon monoxide is exothermic with at least Some of the oxygen present, if any, reacts, it is advantageous to use this heat in a To gain heat extracting unit 34. The one from the

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accruing gas stream 36 in the
The sulfur that is collected is combined with the sulfur that was "removed at 30, and is used as a valuable body product" of this Yerfa ltT ems. Once the gas flow has passed through the separator 40 and the compressor 42, it is discharged through the shaft 44. The WeTbemleitrcag 46 allows _s the gas flow directly over the Schaeht aljzialassem, τβ "for example for the Eatalysatoranstaiflsch a motor breaker Doag for the Äealctorsystem .

The gas emerging from the catalytic reactor of the first stage contains non-limited sulfur dioxide, hydrogen sulphide and carbon dioxide ₉ which are formed in the heat of the first sentence, and elemental sulfur, which is removed from the dam. It was found that the Iircligan des Gas flows containing hydrogen sulphide and sulfur dioxide (according to the JSmtfermem "from sulfur), in the Ifcata- lytic reactor of the second stage, the ajieh with xliaJD ,, yGo ^ Oj. {in which χ and y are as defined above) "is charged, air fetalytiscliem oxidation of the hydrogen sulfide and the catalytic reduction, of the sulfur dioxide and elemental sulfur with simultaneous semkemination of the hydrogen sulfide and sulfur dioxide, as it is primarily present in the test flow are, Biese Emtfemiang leads two named EfeLteriaÜem succeeds in the famous Clams- ^ reaction;

4i.1j.j1

The mach a defimited ¥ receipt of hydrogen sulfide SM requires sulfur dioxide of 2: 1. Well-known GlaTas catalysts are bauxite, various iO.iaimimate and iron oxide

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of air or oxygen in a flue gas heater to increase the concentration of sulfur dioxide in the gas stream. This additional step is not necessary since the material (ie XLa ₂ O ^ · yCOpCO according to the invention with which the catalytic reactor is charged is not poisoned by oxygen. Sulfur dioxide ratio, if desired, can be added directly. This is considered to be a significant advantage of this embodiment of the invention, since it offers greater flexibility in the treatment of gas streams to be processed. If the concentration of hydrogen sulfide is insufficient, additional hydrogen sulfide can be added or a portion of the sulfur dioxide in the gas stream can be reduced with other reducing agents to give the appropriate molar equilibrium. In addition, it is assumed that carbon oxysulfide initially present in the gas stream supplied is at least partially eliminated by the following equation:

, 2 COS + SO ₂ 2 CO ₂ + 3/2 S ₂ (IV)

However, limited amounts of COS can later be formed, especially when carbon monoxide is present in the supplied gas stream. This embodiment of the invention is also carried out at elevated temperatures, generally in the range of about 45O ⁰ C to about 700 ⁰ C or above; It was found, however, that these reactions are carried out at temperatures ranging between about 175 and can ground 4-5O ⁰ C v / v / o significant conversions were made in elemental sulfur. The actual lower temperature limit is determined at least in part for given conditions (eg composition of the feed or product streams) by the vapor pressure of the sulfur formed in each of the catalytic stages. she can

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can be determined by routine experimentation once the other conditions have been established, and can under certain circumstances Conditions are below 175 C.

Depending on the nature and composition of the initial feed gas stream and the conversion (s) desired it may be advantageous or desirable to rearrange the sequence of the reactions taking place. if for example the initial feed gas stream contains both hydrogen sulfide and sulfur dioxide, such as that may be the case with the gases emerging from a coal gasifier, it may be desirable to first use the To oxidize hydrogen sulfide to sulfur, whereupon first the sulfur dioxide is reduced to sulfur and then the Sulfur is removed. Alternatively, a hydrogen sulfide / sulfur dioxide-containing gas stream can be used in a single catalytic reactor with lowering of the concentrations of hydrogen sulfide and sulfur dioxide, as described here, to be edited. Further process variants which are within the scope of the invention will become apparent to the person skilled in the art based on the present disclosure.

The following examples are provided to those skilled in the art for a better understanding and given for the practice of the invention. They are not intended to limit the scope of the invention, but only to illustrate them.

Example I.

6.517 g of La ₂ O ^ and 3 | 317 g of Co ₂ O ^, which means an excess of 0.057 g of Co ₂ O * compared to the stoichiometric 1: 1 ratio, were dry-milled for 3 h in a ball mill at room temperature and in a non-dry mill brought covered platinum dish. The sample was placed in an oven at 200 ^° C., the temperature was increased to 500 ^° C. and held that way for 30 minutes. then

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Jd

the temperature was increased to 110O ⁰ C and held in air for 2 h. The sample was allowed to cool to room temperature, it was ground with a pestle and mortar, placed back into a platinum dish and ^{fired again in air at 1100 °} C. for a further 2 hours. The sample was allowed to cool again to room temperature, removed from the oven, ground with a pestle and mortar and sieved through a sieve with a mesh size of 0.044 mm (525 mesh) to obtain 8.7 g of perovskite-laCoO, with excess COpO ₅ .

Example II

6.517 g of La ₂ O ₅ and 3.26 g of Co ₂ O were ground dry with a pestle and mortar and mixed and ^{fired in air at 1100 °} C. for 4 h in an uncovered platinum dish. After the sample had cooled to room temperature, it was removed from the furnace, rubbed again with a mortar and pestle, and ^{fired again at 1100 °} C. for a further 4 hours. After the second bake, the sample was cooled, remilled and sieved through a 325 mesh screen to remove Perovskite-LaCoO. (i.e. a 1: 1 composition of La ₂ O ₅ -, Co ₂ O ^).

BeisDiel III

The procedure of Example II was followed using 4.562 g of La ₂ O ₅ and 4.564 g of Co ₂ C ₅ to make La ₂ O ₃ . 2Co ₂ O ₅ repeated.

Example IV

The procedure of Example II was followed using 3.259 g La ₂ O ₅ and 4.89 g Co ₂ O ₅ to prepare

La ₂ O ₅ . 3Co ₂ O ₅ repeated.

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Example V

The procedure of Example II was followed using 6.517 g of La ₂ O ₅ and 1.63 g of Co ₂ O ₅ to make 2La ₂ O ^. Co ₂ O ₅ repeated.

Example VI

The procedure of Example II was followed using 5.865 g La ₂ O ₅ and 0.978 g Co ₂ O ₅ to make 3La ₂ O ₅ . Co ₂ O ₅ repeated.

Example VII

Pre-synthesized LaCoO _{5 with} a particle size corresponding to a mesh size of up to 0.037 mm (-400 mesh) (eg produced similar to Example II) is mixed with deionized water in a ratio of about 10 g of powder to 150 ml of water / volume. The resulting slurry was slip cast onto ashless filter paper which was saturated with water. Vacuum is applied to the opposite side of the filter paper to remove supernatant liquid. Fold excess removing v / ater is dried at 70 ⁰ C, while still left on the filter paper of Schlickergußkuchen 17th After drying, the filter cake / filter paper unit is ^{burned in air at 900 °} C. for 4 hours, then ^{kept at 100 °} C. for 1 hour. The body obtained, 0.3 cm thick, is cut into rectangular pellets of pure LaCoO ₅ 0.3 cm χ 0.5 cm. In this example, the catalyst composition is in the form of a carrier, the catalyst material as such being both a catalyst and a carrier.

709827/1045

"St.

Example VIII

One g of presynitized LaCoO, a grain size corresponding to a mesh size of "up to 0.037 mm (-400 mesh) (produced, for example, similar to Example II) was dry mixed with 19 g of yttrium oxide (YpO-; 6%) -stabilized zirconium oxide. The mixture was combined with 8 ml of deionized water to produce a paste which was extruded through an opening with a diameter of 0.32 cm. The resulting extrudate was ^{dried at 35 °} C. for 17 hours, cut into pieces about 0.6 cm in length and 4 burned h at 900 ⁰ C in air to obtain stabilized by yttrium oxide Zirkonoxidpellets, which had a Uenngehalt from 5 weight percent LaCoO-.

Example IX

A solution of 9.80 g of La (EO ₅ ) ₂ and 6.59 g of Co (NOv) ₂ in 34 ml of deionized water was made 94.4 g of 6 % Y ₂ O, stabilized zirconia, sieved to a size of 0.250 to 0.59 mm (-3O / + 6O mesh), added to form a paste. The paste was extruded, dried, cut and fired as set out in Example VIII to give YpO, stabilized zirconia pellets with about 5.5 % LaCoO.

The procedure of the previous paragraph was carried out with non-stabilized Zirconium oxide, magnesium oxide, aluminum oxide or aluminum oxide / silicon dioxide for the formation of catalytic Pellets with about 5.5% LaCoO, repeated.

709827/1045

.33.

Example X

In this example, the catalytic activity of LaCoO, in reducing sulfur dioxide to elemental Illustrating sulfur, six gases (Np saturated with HpO, Np, CO, SOp, Op and Hp) in a stainless steel elbow Steel led. "From the manifold, the gases flowed through a mixing chamber, a stainless steel pipe with a Diameter of 2.54 cm and a length of 45.7 cm, filled with glass balls of 0.635 cm, through a preheating zone, where the temperature of the gas stream is brought to about that of the test reactor, and then to the test reactor, a tube furnace of 5.1 cm outer diameter, which is a quartz tube of T, 27 cm diameter and 45.7 cm length with attached connecting pieces surrounded at both ends. The catalyst, in this case LaCoO, of Example I, sits in the reactor, 7.6 cm above the bottom of the oven, on a small amount of Fiberfrax wool as a support. The catalyst was in a Amount of 0.75 g used. The gases emerging from the test reactor got into a sulfur collector, a heated 250 ml two-necked flask. Samples of this exiting Gas was withdrawn from the flask for analysis with a gas chromatograph.

At an oven temperature of 600-720 ⁰ C, a flow rate of 12 ml / min SOp and 24 ml / min CO the conversion efficiency to elemental sulfur of> 90% on addition of 84 ml / min or 298 ml / min N ₂ was to the gas stream at 680 ⁰ C the conversion efficiency remained about 90 %,

At an oven temperature of 700 ^° C. with a flow rate of 12 ml / min SO ₂ , 46 ml / min CO, 190 ml / min N ₂ and 9 ml / min O ₂ or 12 ml / min SO ₂ , 54 ml / min CO , 180 ml / min N ₂ and 9 ml / min Op with a contact time of about 0.2 seconds in each case

709827/1045

the conversion efficiency was about 100 %.

At an oven temperature of 70O ⁰ C, after the catalyst was in operation for 960 h, with a flow rate of 12 ml / min S0 _2> 24 ml / min CO and 214 ml / min Np and with a contact time of 0.2 seconds the remained Conversion efficiency about 100 %.

The above conditions were continued with changes made to both these and other conditions until a total of 3700 h had elapsed, after which the experiment was terminated. That had catalytic activity not noticeably decreased over this period.

Examples XI - XXIV

In the following Examples XI-XXIV, a sieve reactor system (described below) was used to test the relative catalytic activity of the materials according to the invention. The system was adjusted to give about 60 % conversion efficiency (instead of 100 %) with LaCoO, which made it possible to find even more effective catalyst compositions.

Three gases (Ν «, CO and SOp) were fed into a stainless elbow Brought steel. The gases come from the manifold through a static mixer made of stainless steel 3/8 in. in diameter, 12 in. (30.5 cm) long, and 21 elements (from Denies Corp., Danvers, Mass.) Then into a reactor consisting of a 38.1 cm tube furnace containing a quartz tube 1.27 cm in diameter and 45.7 cm Length, provided with extensions at both ends, surrounds, consists. The catalyst sits 10.16 cm above the reactor Bottom of the oven on a small amount of Piberfrax wool. Of the Catalyst is used in an amount of 0.5 g. The gas emerging from the reactor system enters a sulfur

709827/1046

collector, a Pyrex tube 1.27 cm in diameter and 20.32 cm in length, with extensions at both ends, and a 0.635 cm tube in the center leading to a 0.635 cm stainless steel Millipor filter. The escaping gases from the filter pass into an automatic Carle sampling valve with a timer, the samples injected into a gas chromatograph every 10 min.

The data for various catalytic compositions according to the invention with flow rates of 12 ml / min S0 _p , 24 ml / min CO and 84 ml / min N ₂ (catalyst volume = 0.59 cm; contact time = 0.29 s) are in the following Table I compiled.

In comparison, a sample removed Co ₂ O ₅ 60% SO ₂ at 700 ⁰ C, but the conversion rate decreased rapidly with decreasing temperature, for example dropped at 69O ⁰ C the conversion to 20%. A second sample removed only 27 % at 700 ° C, while a third sample removed only 5% at 700 ^° C, and a sample of La ₂ O removed only 43 % at the same temperature. Therefore, one would not expect from this information that combinations of LaCoO., With either excess Co ₂ O, or La ₂ O, would be as effective as unexpectedly and as shown above.

Examples XXV - XXXII

In the following Examples XXV-XXXII, a further expanded reactor system (which allows the synthesis of gas compositions which come very close to furnace gases) was used. Eight gases (N ₂ , CO, SO ₂ in N ₂ , NO in N ₂ , O ₂ , H ₂ , CO _2, and CH ₄ ) were introduced into a stainless steel elbow. From the manifold the gases pass through a stainless steel tube 2.54 cm in diameter and 18 inches long filled with

709827/1045

Table I.

Case formula
game

XII

LaCoO ₅

LaCoO,

XIII LaCO,

LaCO,

LaCO,

Output burning; substances temp. and time

La ₂ O ₅ Co ₂ O ₅

La ₂ O ₅ Co ₂ O ₅

La ₂ O ₅ Co ₂ O ₅

La ₂ O ₅ Co ₂ O ₅

Nitrates

XVI La ₂ O ₅ . Co ₂ O ₅ oxides

XVII La ₂ O ₅ . 2Co ₂ O ₅ oxides

XVIII La ₂ O ₅ . 3Co ₂ 0 ₅ oxides

see example I.

110O ⁰ C / 8h; after 4 hours they are rewed

1100 ° C / 8h; after 4 hours they are rewed

1100 ° C / 8h; after 4 hours they are rewed

1100 ⁰ C / 16h; after 12h rewind

see Example II

see BeisD.II

see Example IV

X-ray analysis of the catalyst add ainmens ο t zung

Perovskite; some La (OH) ₅ detected

Perovskite; some La (OH), detected

Perovskite; low COpO ^ -Ijber-

shot

Perovskite; no Co ₂ 0 "-over-

shot

Perovskite; some La ₂ O _{5 and} Co ₅ O.

proven

Temp. At maximum COS- at 700 C

that no education distant

Reaction at no- SO ₂ in %

Entry of third temp.

77

420 ⁰ C

440 ⁰ C

410 ⁰ C

37O ⁰ C

450 ⁰ C

primarily LaCoO ₅ ; secondary

Co ₅ O ₄

LaCoO,

49O ⁰ C

500 ⁰ C

480 ⁰ C

sec. C0

5O /

14 %

6 % at 63 490 ^° C

10% at 45O ⁰ C

5 50 at 480 ⁰ C

18 % at 510 ⁰ C

track

7 % at 54O ⁰ C

67

64

57

58 57

55

CD (Jl CO CO NJ

Table I continued

Case formula
game

XIX 2La ₂ O ₃

XX 3La ₂ O ₃

XXI LaCoOr,

XXII LaCoO,

XXIII LaCoO,

XXIV LaCoO,

Output burning; X-ray analysis substances temp. and the catalyst time composition

Co ₂ O ₃ oxides

Co ₂ O ₃ oxides

Oxides

Oxides

Oxides

Oxides

at 7OO ^U C distant

compare
Example V.

compare
Example VI

110 ° C / 4h; rewind after 2 hours; cooled in air

1100 ° C / 4hj grind again after 2h; in the oven cooled down

1100 ° C / 4h; rewind after 2 hours; cooled in the oven

1100 ° C / 4h; cooled in air

prim. LaCoO.,; sec. La ₂ O,

prim. LaCoO ,; sec. La ₂ O, temperature at max COS

of no education

Reaction at no- SO ₂ in%

Entry of third temp.

480 ⁰ C

50O ⁰ C

47O ⁰ C

47O ⁰ C

5 ° / _n at 410 ⁰ C

4% "at

28 %

available

11 %

56

56

64

64

65

64

cn co co

26 5 3 3

Glass balls with a diameter of 0.635 cm), which is used as a mixing chamber then to a water injection zone, which consists of an injection pump, Sage Kodel 341, with a 1o ml plastic syringe ", which is connected to the system by a 0.518 cm polyethylene pipe. Behind the water injection zone the gases flow through an inverted, heated, U-shaped glass tube that leads directly to the reactor, a tube oven of 38.1 cm, which surrounds a long quartz tube 1.27 cm in diameter and 45 »7 cm in length, which at both ends Has attachments. The catalyst sits on a small amount in the reactor four inches above the bottom of the furnace Piberfrax wool. The amount of catalyst used is 0.5 g of material without a carrier or 1.5 g of material with a carrier. The outflowing material is the piston with a Syringe removed for gas chromatographic analysis.

The reaction conditions are not optimal, but were chosen so that slight. Changes in the gases or the catalytic activity and selectivity would cause strong changes in the products. The flow rates are adjusted so that the reactor is at its maximum Conversion is unable. This allows for greater flexibility in determining the effect and the different ones Response parameters when varying on the product flow.

The 0 ₂ / S0 ₂ ratio is kept constant at 8.0 / 0.8 = 10. The ratio of all reducing agents (Hp, CO, H ₂ S and CH.) To oxidizing agents (O ₂ and SO ₂ ) is kept constant at 18 / 8.8 = 2.04 or just above the stoichiometrically required value. In the case of examples in which no water is contained in the supplied gas stream , the flow rate is increased by 18 ml / min in order to keep the total flow rate constant.

709827/1045

The total flow velocity is adjusted not when 0.3 ml / min of NO is added to the supplied gas stream

Example XXV "

The catalyst is pelletized LaCoO ,, prepared according to the Arb.eitsA ^ else of Example VII, except that the dried cake baked one hour heil100 ⁰ C, "before it is cut into pellets. The feed is 50 ml / min 1.6 Soiges SO ₂ (about 3243 ppm), 114 ml / min N ₂ , 8.0 ml / min O ₂ , 38 ml / min CO ₂ (about 15 %) , 18.7 ml / min H ₂ O ( about 7.6) ■>) and 18 ml / RNIN CO (about 7.2 ^Γ, Ί). the reactor temperature is 700 ⁰ C. After passage through the reactor verhieben 400 ppm SO _2, 0.2 </ ό O ₂ and 0.25 Si CO, and were formed 850 phr of H ₂ S and 400 ppm COS This corresponds to a removal efficiency of SO ₂ of about ^88: ό; a reduction of the flow velocity (equivalent to an increase in contact time) to 227 ml. / min by lowering the flow rate of the Np. increases the conversion to 91/6.

Example XXVI

Example XXV was repeated except that no water was added and the nitrogen flow rate was increased to 132 ml / min. After passage through the reactor, 380 ppm of SO ₂ , 0.08 ^c , £ O ₂ and 0.1 % CO remained, and less than 20 ppm of H ₂ S and only a trace of COS was formed.

Example XXVII

Example XXV was repeated except that the CO flow _{rate was decreased to 9 ml / min, the N 2} flow rate was decreased by 57 ml / min and 9.0 ml / min CH, and 57 ml / min 0.53 % NO in N ₂ (corresponding to 0.3 ml / min NO;

70 9 827/1045

1222 ppm NO) were added to the supplied gas stream. To. _{100 ppm SO 2} 2.1 70 CiI., 0.06 ^c / o O ₂ and a trace of CO remained through the reactor _{, and 100 ppm H 2} S and 42 ppm COS had been formed. The removal efficiency for SOp is about 97/6.

Example XXVIII

Example XXV is repeated, with the exception that pellets of yttria-stabilized zirconium oxide / LaCoO * * from Example VIII were used as the catalyst material. After passage through the reactor, 366 ppm SO ₂ , 0.08 % O _2, and 0.25 % CO remained, and 1,300 ppm H ₂ S and 190 ppm COS had formed.

Example XXIX

Example XXVIII was repeated with the exception that 0.3 ml / min (~ 1200 ppm) NO was added to the supplied gas stream. After passage through the reactor, 250 ppm SO ₂ , 0.10 % O ₂ and 0.25 ^L / o CO remained, and 1,300 ppm HpS and 160 ppm COS had formed. This example and Examples XXVII and XXXI show that the addition of NO aids in _{the reduction of SO 2.}

Example XXX

Example XXVIII was repeated except that the CO flow was reduced to 9 ml / min and 9 ml / min H ₂ was added to the gas flow introduced. After passage through the reactor, 190 ppm of SO ₂ and 0.10 % O ₂ remained, and 1,300 ppm of H ₂ S and 100 ppm of COS had formed. This approach shows that H ₂ O prevents the formation of COS.

709827/1 OAB

• V / i.

Example XXXI

Example XXX was repeated with the exception that 0.3 ml / min (1200 ppm) NO was added to the supplied gas stream. After passage through the reactor, 94 ppm SO ₂ , 0.08 % O _2, and 0.45 % CO remained, and 1200 ppm H ₂ S and 120 ppm COS had formed. This example and Examples XXVII and XXIX show that the addition of NO aids in _{the reduction of SO 2.}

Example XXXII

Example XXVIII was repeated except that no water was added and the nitrogen flow rate was increased to 132 ml / min. After passage through the reactor, 165 ppm of SO ₂ and 0.10 % O ₂ remained and 1200 ppm of H ₂ S and 300 ppm of COS had formed. In comparison with Example XXX, this approach shows that the presence of water prevents the formation of carbon oxysulphide. The approach also shows that H _{2 is} an effective reducing agent, but also triggers the formation of HpS with this supported catalyst.

Example XXXIII

In this example, a reactor system is used in conjunction with a coal furnace to investigate the influence of the fly ash from the coal on the catalysts. A portion of the combustion gases from the furnace was withdrawn through a stainless steel pipe 2.54 cm in diameter into which the reducing agent (CO) was introduced. In addition, since the. _{SO 2 formed} during the combustion of the coal was below the normally expected amount, further SO _{2 was also} introduced at this point. The gas stream was then passed through an ash filter to remove some of the particulate material and then through a stainless steel mixing tube to make it homogeneous

709827/1045

265G327

To ensure gas mixture. The catalyst was placed in a reactor tube heated by a 20 inch Lindberg tube furnace which maintains the catalyst bed at the desired temperature. The sulfur formed in the catalytic reactor was condensed out in a trap just below the furnace. The system also has openings in front of and behind the reactor and behind the 3chv / ef elf for taking gas samples for analysis purposes. Four catalyst compositions / LaCoCz on ω-ΑΙρΟ. ,, LaCoO., On Forton SA-3232 (AIpO- + oiOp), and pelletized IaCoO ₇ . (2 different samples) _7 were tested for catalytic conversion in the reactor system prior to passing combustion gases over the catalyst to determine initial activity. The coal furnace was then operated for a week and the conversion performance was tested again. Finally, fly ash samples from the combustion gases were ground together with a small amount of kiln ash and unburned coal and added directly to the top of the catalyst bed and the conversion performance tested again. In all cases, the reduction in SOp was greater than 90? O, both before and after the poisoning tests, and there was no loss of catalytic effectiveness. Large amounts of HpS and COS were formed with the LaCoO., On the AlpO- + SiOp support, probably due to the formation of CoAl ₂ O, on the catalyst surface by reaction with the support material. Therefore, AlpO- + SiOp is not a preferred carrier. The flow rates for these tests were 1538 ml / min K ₂ , 17.6 ml / min or 24.5 ml / min SO ₂ and CO as a stoichiometric balance for Op and SO ₂ . Some H ₂ O is always present, usually about 0.5 to 1%.

709827/1045

Example XXXIV

A gas stream was artificially produced in such a way that it contained 15 % CO ₂ , 3.6 % H ₂ O (gas), 1.0 Jo H ₂ S, 1 So SO ₂ , 0.5 Si O ₂ and 79.9 % H ₂ contained. This gas stream is representative of the emission from a catalytic reactor of the first stage, where the gas stream containing sulfur dioxide is 14 % SO ₂ , 3 % O ₂ and 83 % N ₂ and the reducing gas is 7.6 $ ό CO ₂ ,

7.1 pi H ₂ O (gas), 17.5; ό H ₂ , 19.2 _; Contains ό CO and 48.6 % IT ₂ , with the total composite flow 3.6> ό CO ₂ , 3.4 % H ₂ O (gas), 8.4 _{% H 2} , 9.2 Yo CO, 7.3 > $ 3C ₂ , 1.5> SO ₂ and 66.6 $ Ä ^ ₂ .

Using the reactor of Example X hei a temperature of 660 ⁰ C and a gas hourly space velocity of 2000 on a material of the formula La ₂ O-.

1:02 Co ₂ O, the H ₂ S .wurde by more than 94 Yo to 0.055%, and the SO ₂ to 24 · ό to 0.76% reduced.

After 24 hours under the above conditions, O _{2 was} removed from the supplied gas stream, so that SO _{2 was} the only oxidizing agent present. The exiting gas stream then contained 0.089 yo H ₂ S (91 ^f / o removal) and 0.57 ^c / o SO ₂ (43 yo removal). These values show that the reduction of the SOp via the Claus reaction in the previous case is partly offset by a certain oxidation of the H ₂ S to SO ₂ by Op. In particular, however, these values show that the material brought into the reactor is not poisoned by air or oxygen in the gas stream supplied.

The HpS content in the gas stream fed in was then increased to 2 % (O ₂ again at 0 %) . Under these conditions the exiting gas stream contained 0.14 % H ₂ S (93 % removal) and 0.23 % Yo S0 _p (77% removal).

709827/1045

Then -0.5 % CU was added to the incoming gas stream and under these conditions the exiting gas stream contained 0.11 % H ₂ S (95 % removal) and 0.59 % SO ₂ (41 % removal).

Finally, the HpS content in the gas stream fed in was increased to 3%. Under these conditions, the effluent gas stream contained 0.66% H ₂ S (78% removal) and 0.4-3% of SO ₂ (57 Yo distance).

This example illustrates the various possibilities that can be considered according to the invention, a S0 _? and to process the gas stream containing HpS so that both are converted into elemental sulfur, whereby the concentration of both in the gas stream is reduced. As can be seen from this example, the system parameters are such that many changes are available depending on the products and their concentrations that are to be present in the exiting or final product streams. If, for example, an output stream with an SOg content of 14 % is passed through two separate catalytic converters, first with a reducing gas (first converter) and then with the addition of oxygen, if necessary (second converter), with the removal of sulfur streams in between more than 90 Jo of the SO _{2 is converted} into elemental sulfur with the formation of less than 0.1 % H ₂ S. This occurs regardless of the presence of small amounts of oxygen in the supplied gas streams which, as stated above, do not poison the material brought into the catalytic converter.

Example XXXV

Example XXXIV is repeated with a supplied gas stream which additionally contains a smaller amount (approx. 1 to 1.5 %) methane, with similar results being shown.

709827/1045

-yf- 2653327

Example XXXYI

A gas stream containing 15 % CO, 3.5% H ₃ O (g), 7.0 % H ₂ S, 3.0% SO ₂ , 0.5 % O ₂ and 71 % N ₂ (all volume percent) , was fed through the reactor of Example X with 0.7 ml of La ₂ O,. 3Co ₂ O ₅ of Example IV "at a temperature of 70O ⁰ C and an hourly gas space velocity of about 2000 V / V / h (corresponding to a flow rate of 23.3 ml / min and a residence time of 1.8 seconds), passed, the H ₂ S is reduced by 66% to 2.40 %, the SO ₂ by 81 % to 0.58 % and only 0.070 % COS was formed. With a difference of 10 % the total sulfur removal efficiency in this single pass is about 70 %.

Example XXXVII

Example XXXVI was made using 0.7 ml of 3La _? 0,. Co ₂ O., of Example VI was repeated. H ₂ S was reduced by 63% to 2.60 %, SO ₂ by 87 % to 0.40 % , and only 0.100 % COS was formed. With a difference of 10 % , the total sulfur removal performance for this single pass was about 69/0.

Example XXXVIII

491 g of La ₂ O, and 237.7 g of Co ₂ O are milled two hours in a ball mill and then calcined 24 hours at 110o C ^0. After cooling to room temperature, this mixture is milled 4 hours in the ball mill and fired at 110o further 24 h ⁰ C. The material is ^{cooled to 70O 0} C, kept at this temperature for 16 h, then cooled to room temperature. 669 g of the LaCoO. Obtained (in reality La ₂ O _5. 1.02 Co ₂ O ₅ ) are mixed with 26.76 g (4 %) Methocel binder, and enough water is added to

7 09827/1045

- 2653327

• ve.

■ to make a thick paste. Pellets are produced by pouring this paste into holes 6.35 mm in diameter and 6.35 mm deep in an aluminum block, drying the paste and punching it out. The pellets are then tempered for 15 h at 70O ⁰ C, then gently ground and finally a portion that passed through a sieve with 0.84 mm clear cell width, but not through a sieve with 0.25 mm clear cell width, as below described, used.

Example XXXVI is repeated using 0.7 ml of the material prepared in the previous section. The H ₂ 3 is reduced by SO, '> to 1.40'; ό, the SO ₂ by 83 % to 0.50 % , and only 0.024 % COS was formed. With a difference of 10 % , the total sulfur removal efficiency in this single stage was about 81%.

Example XXXIX

A gas stream containing 7.3 % SO ₂ , 1.2 % CH ^, 8.4; ί PI ₂ , 3.4 Ά H ₂ O (g), 3.6 Yo CO ₂ , 1.5 Yo O ₂ , 9.2 % CO and 65.4 % N ₂ (all volume percent) was passed through the reactor of Example X, which was charged with powdered LaCoO ,, temperature 700 C, gas hourly space velocity 2000 V / V / h, Ratio of reducing agent (CO + H ₂ ) to oxidizing _{agent (SO 2} + O ₂ ) 1.04. The SO ₂ was reduced by 85 % to 1.06 % , with only 1.02 % H ₂ S and 0.080 % COS being formed.

Example XXXX

In this example, which illustrates the catalytic activity of pellets of commercial size, 600 g of the pellets of Example XXXVIII were placed on a perforated quartz plate within a quartz reactor tube 4.52 cm in diameter and 91.4 cm in height. The received catalog

709827/1045 original inspected

2655327

• η.

The analyzer bed was approximately 12.7 cm deep. Two gas mixtures, one containing CU and Np and the second containing CO, Hp, CH 1, COp and Np, were combined with SOp and HpO to form a mixture of the composition as in Example XXXIX. These gases were then passed into a silica kettle chamber and then into a preheating zone of the quartz reactor tube which contained short sections of quartz tube as the heat transfer medium. The gases then passed through the catalyst bed and into a sulfur collector. The S0 _? was reduced by 93 % to 0.50 % while only 1.30 % H ₂ S and 0.070 % COS were formed.

Example XXXXI

Example XXXIX was repeated in the reactor of Example XXXX using 10 Torex honeycomb structures 4.57 cm in diameter and 2.54 cm in length, which were coated with a total of 130 g of LaCoO ^. The SOp was reduced by 88% to 0.87 % , while only 1.30 % HpS and 0.077 % COS were produced.

Example XXXXII

The material of Example XXXVIII is brought in two reactors as in Example X, the are arranged in series and are operated at 700 ⁰ C. At a space velocity of 2000 V / V / h and intervening sulfur condensation and adjustment of the gas compositions of Example XXXIX so that the reducing gas is 4 % in excess over the amount required to reduce both the oxygen and the sulfur dioxide, the emerging gases contained 1.28 % HpS, 0.070 % COS and 0.76 % SO ₂ after the first reactor and 0.70 % H ₂ S, 0.044 % COS and 0.20% SO ₂ after the second reactor.

709827/1045

OHiQiN INSPECTED

Example XXXXIII

53.68 g of lanthanum acetate La (C ₂ H ₅ O ₂ ) ^. nH ₂ O (analysis: 41.24% La) and 24.91 g cobalt acetate Co (C ₂ H ₅ 0 ₂ ) ₂ . 4H ₂ O were "mixed dry at room temperature for 4 hours in a ball mill, transferred to a porcelain dish and" ^{dried at 150 °} C. for 4 hours. It was then introduced into an oven and the temperature was increased to 200 ^° C. and held for 2 h. The sample was then calcined 4 hours at 35O ⁰ C.

An artificial gas flow was adjusted to a content of 15% CO ₂ , 7% H ₂ S, 3.0% SO ₂ , 0.5 % O ₂ and 74.5% N _2. Using the reactor of Examples XXV-XXJiII with an hourly gas space velocity of 2000 above the material of this example (ie La ₂ O.,. Co ₂ O-), the following exiting components resulted as a function of the reactor temperature, measured just above the catalyst bed:

S% (difference

Temperature (C) H ₉ S% COS% SO ₉ % rence of total wall

^{d ά} 1096) on p

485 0.62 0.015 1.65 7.715 77.2 / 440 0.15 0.015 1.44 8.395 84.0% 400 0.16 0.014 1.42 8.406 84.1% 330 0.15 not 0.68
after
grasslands 9.170 91.7% 250 0.08 not 0.73
after
grasslands 9.190 91.9%

Based on the initial concentration of sulfur-containing components, the amount results at 485 ° C to a total conversion to elemental sulfur of 77.2%, and the results at 250 ⁰ C amounts to a total conversion to elemental sulfur of 91.9%. The occasional inconsistency of the trends in H ₉ S and SO ₉ concentrations with temperature is due to the difficulty

709827/1045

2650

ability to control the balance of these components with the flow meters used for this particular system.

Example XXXZIV

Example XXXXIII is repeated, with the exception that instead of the fired firing at 35O ⁰ C, the sample twice for 2 h at 700 ⁰ C and mixed between these last two firings with a mortar and pestle.

An artificial gas flow was adjusted to a content of 15% CO ₂ , 2% H ₂ S, 1% SO ₂ , 3.5% H ₂ O (g) and 78.5% N _2. The reactor had two ovens (in the arrangement described for Examples XXV-XXXII) one behind the other with an interposed sulfur condenser; the components leaving each stage as a puncture of the temperature measured in the catalyst beds and the gas hourly space velocity were as follows:

Temperature level hourly H ₂ S,% SO ₂ ,% S,% (Dif- total conversion ( ⁰ C) gas space limit of 3% conversion speeded to 3

1 hour after the start of the approach: 1 6000 0.40 0.23 0.12 0.09 2.37 79% 384 2 6000 0.06 0.20 0.07 0.040 2.74 91.3% 340 1 3698 0.42 0.18 0.10 2.40 80.0% 350 2 3698 0.07 0.10 0.02 2.93 97.7% 350 after beginning of Approach: 0.025 24 hours 1 2000 0.25 0.02 2.63 87.7% 300 2 2000 0.10 0.015 2.83 94.3% 300 1 2000 0.24 Approach: 2.66 88.7% 280 2 2000 0.03 0.18 2.95 98.3% 260 2 2000 0.02 0.009 2.955 98.5% 250 2 2000 0.02 2.96 98.7% 240 2 2000 0.02 2.965 98.8% 214 after beginning of 48 hours 1 3200 2.71 90.3% 300 2 3200 2.951 98.4% 214

709827/1045 original inspected

COS was not detected under any of the above conditions. The end result, based on the initial 3 % sulfur components, means a 90.3% conversion to sulfur in one stage and a 98.4% conversion to sulfur after a second stage.

In certain cases, in which the gas stream has a composition which differs from that above or used in the above examples, the catalytic conversion efficiency can be of the order of about 80%. However, under suitable conditions and with suitably composed gas streams, conversion rates of the order of 90% can be achieved.

709827/1045

Claims (1)

Claims 1. A method for removing hydrogen sulfide and sulfur dioxide from a gas stream, characterized in that the gas stream containing hydrogen sulfide and sulfur dioxide through a reactor chamber, the XLa ₂ O ^. yCOpCU, where χ and y can be varied independently of one another from 1 to 3 inclusive, passed and catalytically converted into a product stream containing elemental sulfur and water at a sufficiently high temperature and that the elemental sulfur is then removed from the product stream. 2. The method according to claim 1, characterized in that x = y. 3. The method according to claim 1, characterized in that x Φ y. . ■ 4. The method according to any one of claims 1 to 3, characterized in that the elemental sulfur is in the presence is formed by oxygen in the gas stream. 5. The method according to any one of claims 1 to 4, characterized in that XLa ₂ O ^. yCOpO., is used on a magnesium oxide or zirconium oxide carrier. 6. The method according to any one of claims 1 to 5, characterized in that xLapO ^. yCOgO ^ in situ with carbon monoxide or hydrogen is pretreated at an elevated temperature prior to contact with the gas stream. 7. The method according to any one of claims 1 to 6, characterized in that xLa ^ O ^. yCOgO ^ with carbon monoxide or hydrogen at an elevated temperature in another 703827/1045 ORiGfMAL INSPECTED 2653327 Oven as the reaction chamber pretreated and the pretreated Material is brought into the reaction chamber. 8. The method according to any one of claims 1 to 5, characterized in that XLa ₂ O ₅ . VCo ₂ O ₇ - is pretreated with a gas stream containing hydrogen sulfide or sulfur dioxide at an elevated temperature in a furnace other than the reaction chamber and the pretreated material is brought into the reaction chamber. 9. The method according to any one of the preceding claims, characterized in that the xLapO. yCOpO · * with carbon monoxide or hydrogen and sulfur dioxide or hydrogen sulfide at at least one higher temperature in one or more different from the reaction chamber Furnaces pretreated and the pretreated material is brought into the reaction chamber. 10. A method for removing hydrogen sulfide and sulfur dioxide from a gas stream, characterized in that the gas stream containing hydrogen sulfide and sulfur dioxide is ^{heated to a temperature of about 450 to about 700 0} C, the heated gas stream through a reaction chamber, the xLa _? 0 ^. yCOpO ^, where χ and y can be varied independently of one another from 1 to 3 inclusive, is passed for the catalytic generation of a product stream which contains elemental sulfur and water, and then the elemental sulfur is separated from the product stream. 11. The method according to claim 10, characterized in that χ = y. 709827/1045 12. The method according to claim 10, characterized in that that χ Φ y. 13. The method according to any one of claims 10 to 12, characterized characterized in that the gas stream for the oxidation of part of the hydrogen sulfide to sulfur dioxide and thus to adjust the ratio of hydrogen sulfide to sulfur dioxide in the gas stream air or oxygen is added and the formation of the elemental Sulfur runs off in the presence of excess air or oxygen. 14. The method according to claim 13, characterized in that enough air or oxygen to adjust the ratio of hydrogen sulphide to sulfur dioxide is fed to about 2: 1. 15. The method according to any one of claims 10 to 14 »characterized in that that xLapO,. yCOpO ^ on a magnesium oxide or zirconium oxide carrier is used. 16. A method for removing hydrogen sulfide and sulfur dioxide from a gas stream, characterized in that the gas stream containing hydrogen sulfide and sulfur dioxide passes through a reaction chamber, the derivatives of the compound xLapO ₇ . yCOpO., after contact with the gas stream, derivatives of XLa ₂ O-. yCOpO ~ after pre-reduction with carbon monoxide or hydrogen or derivatives of xLapO ^. yCo ₂ 0 ~ after pre-reduction with carbon monoxide or hydrogen and contact with the gas stream, where χ and y can be varied independently of one another from 1 to 3 inclusive, is passed for the catalytic generation of a product stream at a sufficiently high temperature, the elemental sulfur and water contains, and that the elemental sulfur from the pro- 709827/1045 öakt Strom is emtfeisnt * 17 Terfaniren after Jü ^ pjciieh 16, dadnaarch marked, that χ = j » 18. ITeirfahren to ünspnach 16, dadiaxeh marked, that X ^ y. " 19. Procedure do one of Insprlche 16 Ms 18, characterized in that it! At a Tempejca'teii! ' of the G-assitrom of the Realdfcioiasifcannejc yum. about 4-50 "to- about 70O ⁰ C! from- läaaft. 20. TeiriabaceH Bacli aH den? Aiosjpipiidäie 16 T to 19, daitarela. gefeeM33seiclaiii © it, that the CasstjC © M aajr oxidation of a salvation of the scübssisJDslwasseiicstoffs sm SclnweifeldiiDKid TEcnid daüiiit Einsteliraiig des Teirlialtaiisses .. "rom SctafefelwasseicstofJ: Sekweieldiosid in the GsssitacoM liiait © dei? Sanaejcstoff zioge— Mird Tand that the image of the eleaentareii sulfur Gegeraraorfc mbeicseMissigeT IniiFt odei? iabeTscMassigeii oxygen aWLämft. .Tejcfalajcen macEa. a dejc iMspTmelie 16 ibis 20, thereby geikeiEiiiizeichiiiet that the Deücivate on a odeir% i] ßk; ©] noxid — SiESgeüP used 22 «Teirfalnren after a dea? ^ jasper area 16 ibis 21, geikeniLzeiehnet that as BeriiTate C! © S ^ and IaJO ₁ JS eiaage sets 23 · Te ^ falDreM naadh. itaspiraeli 22, because it is confessed that and l £ uO „S in an intimate mixture 24 · m ITeürJuSiiEreiQ. y ^ jfi JEntfeiüEieM ttosi Schwsfeldi © 3cid from a Sliwefel.aJ.Gxld. containing GasstjDom, dadujceh gelceissi— draws that a gas stream containing sulfur dioxide and carbon monoxide or hydrogen through a reaction chamber, the derivatives xla ^ O,. yGOrß-z after pre-reduction by carbon monoxide or hydrogen, derivatives of yCOpO., after contact with the gas stream or derivatives of XLa ₂ O, · yCOpO ^ after pre-reduction by carbon monoxide or hydrogen and contact with the gas stream, where χ and y can be varied independently of one another from 1 to 3 inclusive, for the catalytic formation of a product stream is conducted at a sufficiently high temperature, which contains elemental sulfur and carbon dioxide or water, and that the elemental sulfur is then removed from the product stream. 25. The method according to claim 24 »characterized in that χ = y. 26. The method according to claim 24 »characterized in that x Φ y. 27. The method according to any one of claims 24 to 26, characterized in that that the formation of the elemental sulfur takes place in the presence of oxygen in the reaction chamber. 28. The method according to any one of claims 24 to 27, characterized in that carbon monoxide or the hydrogen present in the gas stream is kept within + 15 % of the stoichiometric amount required for the complete reduction of all oxidizing agents in the gas stream. 29. The method according to any one of claims 24 to 28, characterized in that the temperature of the gas stream in the reaction chamber between about 450 and about 700 ⁰ G is kept. 709827/1045 .6. 30. The method according to any one of claims 24 to 29, characterized in that CoSp and La ₂ O ₂ S are used as derivatives. 51 · The method according to claim 30, characterized in that CoS ₂ and LapOpjS are used in an intimate mixture. 32. The method according to any one of claims 24 to 31, characterized characterized in that the derivatives are used on a magnesium oxide or zirconium oxide carrier 33. A method for lowering the concentration of carbon oxysulphide and sulfur dioxide in a gas stream, characterized in that the gas stream containing carbon oxysulphide and sulfur dioxide passes through a reaction chamber containing a material of the formula XLa ₂ O ₅ · yCo ₂ 0-, where χ and y are independent of one another can be varied from 1 to 3, derivatives of xLa _o 0-. yCo ₀ 0 ~ after contact with the gas flow. Derivatives 2 2 ^J 2 ο ° ' of xLapO- · yCOpO ^ after pre-reduction with carbon monoxide or hydrogen or derivatives of XLa ₂ O ,,. yCO ₂ O ,, after pre-reduction with carbon monoxide or hydrogen and contact with the "gas stream, is passed for the catalytic formation of a product stream at a sufficiently high temperature which contains elemental sulfur, and that the elemental sulfur is then removed from the product stream . 34 · The method according to claim 33, characterized in that it is carried out at a temperature of the gas flow in the reaction chamber of about 450 to about 700 C. 35. The method according to claim 33 or 34, characterized in that χ = y. 709827/1045 -Hf- 36 · Missing near. Speech. 33 »daduEren indicated that χ / y- ■ '- 37. Yerffateren naek one of the Inspriielie 33 "to 36, marked daäujceHi, that the material or the derivatives on a Magnesium oxide or zirconium oxide bearings are used. 38 » Yerfalaren aar production of a catalytic material, which is isolated, that a material of the ΙΌπββΙ ^ bsufl- ^ . j € o »j © 2, wolbei s and j ninablaangig tone from 1 to 3 possible. It is possible to vary, with monoxide or hydrogen sulphide "in the case of erliöliter Teiaperatiar formation of a material with catalytic JOrfciidLifcat" in the manufacture of elemental sulphur from SetossTefeldiox hydrogen sulphide or KoM-enosysTiilfid is treated since the present from Samerstoii oil 39 · Expire nadto. Carrions. 38 dadiorcli gekennzeidinet that the Belaandliung! At about 500 ⁰ C Ms occurs about TOO. 40. Veriakren naern Jmspraicla 38 or 39 »daäiarck that χ = j. 41. ¥ erianren nadli J5msprjacli 38 or 39 »daäurcii c Φ γ. 42. Catalytic material, divided up by coating a sheet material of the Foreel xla ₂ 0 "" jüoJQ ~ ₉ where χ rastä y iianaT are always varied from 1 "to 3 ©, with celeneon oxide or hydrogen" at ErMaSater 43. Terfanren «cc production of a jfcatalytisemen limaterials, ■ dadiarcii gekemozeicnnet that an oil material of the lOinmel »Where χ land j nanometers from each other -J. can be varied from 1 to 3 inclusive, with a Gas stream containing sulfur dioxide at elevated temperature to form a material with catalytic Activity in the production of elemental sulfur from sulfur dioxide, hydrogen sulfide or carbon oxysulfide is treated even in the presence of oxygen. 44. The method according to claim 43, characterized in that the B
will. the treatment is carried out at about 500 to about 700 ° C 45. The method according to claim 43 or 44, characterized in that χ = y. 46. The method according to claim 43 or 44 »characterized in that that x ^ y. 47. Catalytic material made by treating a material of the formula XEa ₂ O ^. yCo ^ O ,, where χ and y can be varied independently of one another from 1 to 3 inclusive, with a gas stream containing sulfur dioxide at an elevated temperature. 48 Process for the production of a catalytic material, characterized in that '"is a material of the E-formula xEapO, · yCOgO-j, where χ and y are independent of one another from 1 to 3 inclusive, with carbon monoxide or hydrogen and a sulfur dioxide containing Gas flow at elevated temperature to form a material with catalytic activity during manufacture of elemental sulfur from sulfur dioxide, hydrogen sulfide or carbon oxysulfide even in the presence is treated by oxygen. ? 0982? / 104B • J. 49. The method according to claim 48, characterized in that the treatment with carbon monoxide or hydrogen and sulfur dioxide is carried out in two separate stages will. 50. The method according to claim 48 or 49, characterized in that χ = y. 51. The method according to claim 48 or 49, characterized in that xjly, 52. Catalytic material made by treating a material of the formula XLa ₂ O. * · yCo _? 0 ^, where χ and y can be varied independently of one another from 1 to 3 inclusive, with carbon monoxide or hydrogen and a gas stream containing sulfur dioxide at an elevated temperature. 53. The method according to claim 1, characterized in that it is at an elevated temperature in the range of. about 175 to about 700 ^° C. is carried out. 54. The method according to claim 16, characterized in that it is at a temperature of the gas stream in the reaction chamber of about. 175 ° C to about 700 ⁰ C is carried out. 55. Catalytic material for the reduction of sulfur dioxide to elemental sulfur, consisting of or containing a material of the formula xLa ^ O ^ · yCOpO ^, where χ and y can be varied independently of one another from 1 to 3 inclusive, with the proviso that χ φ y. 56. Catalytic material according to claim 55, characterized in that that it contains or consists of LaCoO in combination with excess La «0 ~. 709827/1045 57. Catalytic material according to claim 55 , characterized in that it contains or consists of IaCoCU in combination with excess cobalt oxides. 709827/1045