WO1997018028A1

WO1997018028A1 - Gas treating process

Info

Publication number: WO1997018028A1
Application number: PCT/US1996/015314
Authority: WO
Inventors: Mark A. Plummer; John J. Waycuilis
Original assignee: Marathon Oil Company
Priority date: 1995-11-14
Filing date: 1996-09-25
Publication date: 1997-05-22
Also published as: CA2230849A1; AU7117696A

Abstract

A process for removing hydrogen sulfide and other components, such as water, low molecular weight hydrocarbons, and carbon dioxide, which are contained in a gaseous feed stream and converting hydrogen sulfide to elemental sulfur and hydrogen. In accordance with the process, a gaseous feed stream containing hydrogen sulfide and other components is contacted with a polar organic solvent having a quinone and a complexing agent dissolved therein. The complexing agent must have a pKb value of less than about 13.0. Reaction of the hydrogen sulfide in the gaseous feed stream with quinone results in an increased conversion of quinone to hydroquinone at low reactor temperatures and H2S partial pressures and in increased sulfur recovery. In additon, the presence of a complexing agent increases hydrogen production selectivity in the dehydrogenation of hydroquinone to quinone and hydrogen. The polar organic solvent also functions to dissolve a significant portion of the other components from the gaseous feed stream which are separated and recovered as products.

Description

GAS TREATING PROCESS

FIELD OF INVENTION:

The present invention relates to a process for removing water, low molecular weight hydrocarbons and or carbon dioxide in addition to hydrogen sulfide from a gaseous stream in one processing unit, and more particularly, to such a process for removing and recovering water, low molecular weight hydrocarbons and/or carbon dioxide from a gaseous stream in a single processing unit wherein hydrogen sulfide which is initially contained in the gaseous feed stream is also converted to elemental sulfur in the same processing unit. DESCRIPTION OF RELATED ART:

Numerous industrial processes, particularly those pertaining to the petroleum industry, generate gaseous by-products containing hydrogen sulfide, either alone or in a mixture with water and/or other gases, such as, methane, carbon dioxide, low molecular weight hydrocarbons, nitrogen, ammonia etc. In addition, natural gas which is produced from subterranean formations often contains similar gases to those gaseous by-products listed above.

Many processes have been developed to remove these components from such gas streams prior to transportation and/or further processing thereof. For example, U. S. Patent No. 3,039,251 (Kamlet) discloses simultaneously removing water, hydrogen sulfide, mercaptans and carbon dioxide from gas, such as natural gas, by contacting said gas with tetrahydrothiophene-1 , 1- dioxide (sulfolane) or homologues thereof. U. S. Patent No. 4,359,450 (Blytas et al.) discloses the removal of H₂S CO₂ and COS from gaseous streams characterized by the reaction of H₂S to crystalline or solid sulfur, the absoφtion of C0₂ and COS, the desorption of C0₂ and COS, the hydrolysis of COS, and the recovery of H₂S. In accordance with the first step of the process, the gaseous stream is contacted with an absorbent mixture containing an oxidizing reactant. The absorbent employed are those absorbents which have a high degree of selectivity in absorbing CO₂, COS and H₂S, such as propylene carbonate, N-methyl pyrrolidone, and sulfolane. U. S. Patent No. 3,773,896 (Preusser et al.) discloses a process or washing the gaseous acidic components such as carbon dioxide, hydrogen sulfide and hydrogen cyanide from a gas stream by treating the gas stream with a washing agent that absorbs at least a portion of the gaseous acidic components The washing agent includes a carboxylic acid amide of morpholine preferably containing between 1 and 7 carbon atoms in the carboxylic acid chain Propylene carbonate and sulfolane are identified as previously known washing agents However, all of these prior art processes require further steps or stages to treat hydrogen sulfide by converting it to products which have further utility, such as sulfur, hydrogen, or hydrogen peroxide Further, many processes relating to the petroleum industry generate gaseous by-products containing hydrogen sulfide, either alone or in a mixture with other gases, for example, methane, carbon dioxide, nitrogen, ammonia etc For many years, these gaseous by-products were oxidized by common oxidation processes, such as the Claus process, to obtain sulfur In accordance with the Claus process, hydrogen sulfide is oxidized by direct contact with air to produce sulfur and water However, several disadvantages of air oxidation of hydrogen sulfide, including loss of a valuable hydrogen source, precise air rate control, removal of trace sulfur compounds from spent air, and an upper limit on the ratio of carbon dioxide to hydrogen sulfide, led to the development of alternative processes for the conversion of hydrogen sulfide in gaseous by¬ products to sulfur

As detailed in U S Patent No 4,592,905 to Plummer et al , one such alternative process involves contacting within a reactor a feed gas containing hydrogen sulfide with an anthraquinone which is dissolved in a polar organic solvent This polar organic solvent preferably has a polarity greater than about

3 Debye units The resulting reaction between hydrogen sulfide and anthraquinone yields sulfur and the corresponding anthrahydroqumoπe The sulfur precipitates from the solution in crystalline form and is recovered as a product while the remaining solution containing anthrahydroqumone is thermally or catalytically regenerated producing the initial anthraquinone form and releasing hydrogen gas The anthraquinone is recycled back to the reactor and the hydrogen gas is recovered as a product A significant disadvantage of this process is that the reaction between hydrogen sulfide and anthraquinone proceeds at a relatively slow rate, thereby limiting reactor throughput Another disadvantage of this process is that the feed gas must be compressed to provide H₂S partial pressures of from about 6 to about 200 atmospheres which significantly increases the reactor cost A further disadvantage of this process is that hydrogenolysis by-products, i e anthrones and aπthranols, produced during anthrahydroquinone regeneration reduce the selectivity of producing hydrogen and anthraquinone

Thus, a need exists for a process for removing water, low molecular weight hydrocarbons and/or carbon dioxide as products in addition to hydrogen sulfide from a gaseous stream in a single processing unit while converting hydrogen sulfide which is initially contained in the gaseous feed stream to a useful product in the same processing unit A further need exists for a process for increasing the rate which hydrogen sulfide reacts with quinone in the process for converting hydrogen sulfide to sulfur and hydrogen as described above, while decreasing the H,S partial pressure of such reaction

Accordingly, it is an object of the present invention to provide a process for removing water, low molecular weight hydrocarbons and/or carbon dioxide as products in addition to removing hydrogen sulfide from a gaseous stream while converting hydrogen sulfide which is initially contained in the gaseous feed stream to elemental sulfur in the same processing unit

It is another object of the present invention to provide a such a process for the concurrent removal of hydrogen sulfide from a gaseous stream and conversion of hydrogen sulfide to sulfur which is economical

It is still another object of the present invention to provide a process for increasing the rate of reaction between hydrogen sulfide and a quinone which is dissolved in a polar organic solvent

It is a further object of the present invention to provide a process for increasing the rate of reaction between hydrogen sulfide and a quinone while significantly decreasing the partial pressure of hydrogen sulfide in the gaseous feed

It is a still further object of the present invention to provide a process for increasing hydrogen production selectivity during dehydrogenation of hydroquinone SUMMARY OF THE INVENTION

To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, one characterization of the present invention is a process of removing hydrogen sulfide and other components from a gas. The process comprises contacting a gaseous stream containing hydrogen sulfide with a polar organic solvent having a quinone dissolved therein. Substantially all of the hydrogen sulfide and at least a portion of a second component of said gaseous stream which is selected from the group consisting of water, low molecular weight hydrocarbons, carbon dioxide or mixtures thereof are dissolved in said polar organic solvent.

In another characterization of the present invention, a process is provided for decomposing hydrogen sulfide to sulfur and hydrogen The process comprises contacting a gaseous stream containing hydrogen sulfide with a polar organic solvent having a quinone dissolved therein Substantially all of the hydrogen sulfide and at least a portion of a second component of said gaseous stream which is selected from the group consisting of water, low molecular weight hydrocarbons, carbon dioxide or mixtures thereof are dissolved in said polar organic solvent. The hydrogen sulfide is reacted with the quinone to produce sulfur and a hydroquinone in the solvent. The hydroquinone is dehydrogenated to the corresponding quinone and hydrogen

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and, together with the description, serve to explain the principles of the invention In the drawings: FIG 1 is a graph which depicts the rate constants of the two separate mechanisms for conversion of t-butyl anthraquinone (TBAQ) to t-butyl anthrahydroqumone (H BAQ) as a function of the pK„ value of different complexing agents which are dissolved together with TBAQ into a polar organic solvent, FIG 2 is a graph which depicts the activation energy of the two separate mechanisms for conversion of t-butyl anthraquinone (TBAQ) to t-butyl anthrahydroquinone (HTBAQ) as a function of the pKj, value of different complexing agents which are dissolved together with TBAQ into a polar organic solvent,

FIG 3 is a graph which depicts the conversion of t-butyl anthraquinone (TBAQ) to t-butyl anthrahydroquinone (H₂TBAQ) as a function of the ratio of diethyimethytamine (DEMA) complexing agent to TBAQ which are dissolved together into a polar organic solvent, FIG 4 is a graph which depicts the rate constants of the two separate mechanisms for conversion of t-butyl anthraquinone (TBAQ) to t-butyl anthrahydroquinone (HTBAQ) as a function of the partial pressure of hydrogen sulfide in the reactor for feed gases having varying ratios of hydrogen sulfide to carbon dioxide, FIG 5 is a graph which depicts sulfur recovery achieved in accordance with the process of the present invention as a function of the partial pressure of hydrogen sulfide in the reactor,

FIG 6 is a graph which depicts hydrogen production selectivity as a function of the ratio of complexing agent to total quinone, i e t-butyl anthrahydroquinone (HTBAQ) and t-butyl anthraquinone (TBAQ), during the dehydrogenation of t-butyl anthrahydroquinone in the presence of platinum catalysts,

FIG 7 is a graph which depicts hydrogen production selectivity as a function of the pl . value of different complexing agents which are dissolved together with t-butyl anthrahydroquinone (HTBAQ) into a polar organic solvent in dehydrogenation reactor feeds,

FIG 8 is a graph which depicts the conversion of t-butyl anthraquinone (TBAQ) to t-butyl anthrahydroquinone (HTBAQ) as a function of the number of injection stages for hydrogen sulfide (H₂S) into the H₂S-TBAQ reactor, FIG 9 is a graph which depicts sulfur (S.) recovery, as the weight percent of the total S atoms formed in the conversion of t-butyl anthraquinone (TBAQ) to t-butyl anthrahydroquinone (HTBAQ), as a function of the number of injection stages for hydrogen sulfide (H₂S) into the H,S-TBAQ reactor D

FIG 10 is a graph which depicts sulfur (S,) recovery as a function of the molar ratio of water to t-butyl anthraquinone (TBAQ) in the process of the present invention, and

FIG 11 is a semi-logarithmic graph which depicts the hydrogen production selectivity as a function of the dehydrogenation temperature for separate reaction solutions, one of which does not contain water and another of which contains one mole of water per mole of t-butyl anthraquinone (TBAQ) added prior to the sulfur production stage of the process of the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to the removal of water, low molecular weight hydrocarbons, for example ethane, propane, butanes, pentanes and hexanes and/or carbon dioxide in addition to hydrogen sulfide from a gaseous stream in a single processing unit wherein hydrogen sulfide which is initially contained in the gaseous feed stream is also converted to elemental sulfur in the same processing unit Water, low molecular hydrocarbons, and carbon dioxide which are removed from the gaseous stream can be recovered as separate products In accordance with the process of the present invention, the gaseous feed containing hydrogen sulfide (H₂S) is contacted in an H₂S absorber with a polar organic solvent having a quinone and a H₂S complexing agent dissolved therein

The solvent soiubilizes hydrogen sulfide from the feed gas to form a reaction solution which is transported to and maintained in a polymerization reactor at a temperature and a pressure, as hereinafter discussed, and for a time which is sufficient to convert the hydrogen sulfide and quinone to sulfur and hydroquinone The solvent also soiubilizes in the absorber significant portions of the water, low molecular weight hydrocarbons, i e C₂ - C₆ , and/or carbon dioxide present in the gaseous feed stream In addition, the feed gas may contain other sulfur compounds, such as COS, CS, and mercaptans, which are dissolved in the polar organic solvent and converted in the process to H∑S, recycled to the absorber and/or reactor, and converted to sulfur Although descπbed throughout this description as separate components of a single processing unit, the absorber and polymerization reactor may be a single reaction vessel, for example a stirred tank, in which both functions are performed

In accordance with the present invention, the number of injection stages utilized to introduce the hydrogen sulfide containing feed gas into the absorber or reactor where the gas is contacted with a polar organic solvent containing a quinone and a H₂S complexing agent is a factor which significantly increases the conversion of quinone to hydroquinone and elemental sulfur and to ensure the desired S, sulfur precipitate is formed The number of injection stages employed to introduce the hydrogen sulfide feed gas into the reactor or absorber is preferably 1 to 6, more preferably 2 to 5 and most preferably 4

Although not completely understood, the conversion of quinone to hydroquinone in the H₂S absorber and/or polymerization reactor is believed to occur in accordance with five overall chemical mechanisms First, the polar organic solvent forms a charge-transfer complex with the quinone ("mechanism 1 ' ) Secondly, H₂S reacts with a complexing agent ("CA") to form an ion complex ("mechanism 2") in accordance with the following general reaction

CA + H₂S - CAH⁺HS^" (ion complex)

In the conversion of quinone to hydroquinone in the H₂S absorber and/or polymerization reactor, sulfanes (i e , H₂S_X where X generally equals an integer from 2 to 20) may be formed These sulfanes can also react with the complexing agent to form ion complexes which have utility in accordance with the present invention Next, the ion complex reacts with the solvent-quinone complex in two steps to form elemental sulfur and hydroquinone ("mechanism

3a and 3b") Lastly, a reaction occurs which polymerizes elemental sulfur (S) to polymerized sulfur (S_s) which then precipitates out of solution ("mechanism 4")

In accordance with the present invention, applicants have discovered that utilizing a polar organic solvent in conjunction with a complexing agent, which has been selected in accordance with certain parameters set forth below unexpectedly results in very high conversions of quinone to hydroquinone in extremely short periods of time Further, these results have been achieved at reactor temperatures and H₂S partial pressures which unexpectedly are significantly lower than previously thought to be required

The polar organic solvent utilized in the process of the present invention is chosen to have a high polarity and yet remain stable at dehydrogenation temperatures Suitable polar organic solvents include N-methyl-2-pyrolιdιnone,

N, N-dιmethylacetamιde, N,N-dιmethyiformamaιde, sulfolane

(tetrahydrothιophene-1 , 1 -dioxide), acetonitrile, 2-nιtropropane, propylene carbonate and mixtures thereof The most preferred solvent is N-methyl-2- pyrrolidmoπe (NMP) A complexing agent is also incorporated into the polar organic solvent in accordance with the present invention This complexing agent is believed to react with H,S in accordance with mechanism 2 to form an ion complex (CAH^*HS ) Thus, selection of a suitable complexing agent is based in part upon the ability of the complexing agent to react with H₂S to form an ion complex The complexing agent must also be chosen upon its ability to increase the rate constants for mechanisms 3a and 3b while decreasing the activation energies for mechanisms 3a and 3b It has been discovered that the basicity of these complexing agents, as measured in units of pK,,, directly correlates to the increase in rate constants of mechanisms 3a and 3b In general, employing a complexing agents of decreasing pK„ value in the process of the present invention will increase the formation of the ion complex and the rate constant of mechanism 3a (FIG 1 ) In addition, as complexing agent basicity is increased i e pK,, decreased, the activation energies of mechanisms 3a and 3b are decreased (FIG 2) "Activation energy" represents the energy level required to activate 1 mole of reactants to a state sufficiently above the average energy level of all molecules such that reaction may occur Thus, use of a complexing agent of high basicity results in increased ion complex formation and therefor increased conversion of quinone In accordance with the present invention, the pK^ of complexing agents is less than about 13 0, more preferably less than about 90, and most preferably less than about 6 0 The pK„ values are based on K^ (equilibrium constant) of 14 0 for the dissociation of water Suitable complexing agents are selected from amines, amides, ureas, nitrogen containing heterocyclic aromatics, quanidines, imidazoles, and mixtures thereof These complexing agents can also be substituted with alkyl, aryl and organic alcohol groups Examples of suitable complexing agents are n- methylacetamide, pyridine, substituted pyπdines, diethylmethylamine, tπ- butylamme methyldiethanolamine and tetramethylurea The preferred complexing agents are diethylmethylamine (DEMA), methyldiethanolamine

(MDEA), tπ-butylamine, pyridine (PY), and substituted pyπdines Additionally, it is believed that those complexing agents which contain a hydrogen bonding proton, for example, methyldiethanol amine (MDEA), have a greater impact on increasing the rate of mechanisms 3a and 3b The ratio of complexing agent to quinone in the polar organic solvent is also crucial in yielding an unexpectedly high conversion of quinone to hydroquinone (FIG 3) The molar ratio of complexing agent to quinone in the polar organic solvent is about 1 50 to about 2 1 and preferably about 1 10 to about 1 1

In general, the quinone utilized in the process of the present invention is selected from anthraqumones, benzoquinones, napthaquinones, and mixtures thereof and are chosen to maximize its reaction with H₂S Choice of the quinone is based on such properties as the solubility of quinone in the polar organic solvent Solubility is a function of the groups substituted on the quinone For example, alkyl quinones have much higher solubilities than sulfonated quinones Useful anthraqumones are ethyl, t-butyl, t-amyl and s-amyl anthraqumones and mixtures thereof because of their relatively high solubilities in most polar organic solvents

It has further been discovered that, by utilizing a suitable complexing agent in conjunction with a polar organic solvent, both of which are selected in accordance with parameters specified above, that the temperature and H₂S partial pressure required for conversion of quinone can be substantially reduced while the percentage of quinone converted to hydroquinone is increased Preferably, the reaction solution, i e the polar organic solvent having a suitable quinone, complexing agent and hydrogen sulfide dissolved therein, is maintained in the H₂S absorber and/or polymerization reactor at a temperature of from about 0° C to about 70° C , and more preferably about 20° C to about 60° C , and at a H₂S partial pressure of from about 0 05 to about 4 0 atmospheres more preferably about 0 1 to about 3 0 atmospheres, and most preferably about 0 5 to about 2 0 atmospheres These lower temperatures and pressures reduce the design requirements for the H₂S absorber and/or polymerization reactor which results in significant cost savings In addition, the cost of compressing the feed gas to obtain the requisite H₂S partial pressure is significantly reduced At these conditions, some unreacted H₂S in addition to

C02, water and/or low molecular weight hydrocarbons may be removed from the polymerization reactor, separated and recovered by any suitable means as will be evident to a skilled artisan, such as by means of a three phase separator Although discussed throughout this specification as being two separate and distinct compounds, it is within the scope of the present invention to utilize one compound as both the polar organic solvent and the complexing agent as long as one compound can satisfy the criteria for both polar organic solvent and complexing agent specified herein, i e have a high polarity, remain stable at dehydrogenation temperatures, and have a pK, value of less than about 13 0 Applicants have further discovered that, by including a sufficient amount of carbon dioxide in the gaseous feed containing hydrogen sulfide to ensure that a predetermined amount of carbon dioxide is dissolved in the polar organic solvent together with hydrogen sulfide, the rate of reaction between hydrogen sulfide and quinone can be significantly increased over the reaction rate obtained when carbon dioxide is not included in the gaseous feed to the absorber and/or reactor While it is not exactly understood why carbon dioxide increases this reaction rate, it is believed that the presence of carbon dioxide in the gaseous hydrogen sulfide containing reaction solution within the absorber and/or polymerization reactor alters the structure of the quinone, thereby resulting in an increased rate of quinone conversion In accordance with the process of the present invention, the amount of carbon dioxide present in the gaseous feed should be sufficient to ensure that at least 0 05 mole of carbon dioxide are absorbed into the polar organic solvent per mole of quinone contained therein, more preferably 0 10 mole of carbon dioxide per mole of quinone, and most preferably 025 mole of carbon dioxide per mole of quinone

Carbon dioxide may be present in the gaseous stream to be treated in accordance with the present invention or carbon dioxide may be added to the gaseous stream from any readily available source so as to ensure that the amount of carbon dioxide specified above is absorbed from the gaseous stream into the polar organic solvent containing quinone

The presence of water which is dissolved from the feed gas into the reaction solution also results in an unexpected increase in the recovery of sulfur formed during the conversion of hydrogen sulfide and quinone to sulfur and hydroquinone While it is not exactly understood why the addition of water to the reaction solution increases the amount of sulfur which can be recovered from the reaction solution, it is believed that the addition of a small amount of water to the reaction solution likely limits the total solution solubility and water is selectively solubilized over sulfur, i e S_β

The treated feed gas is removed from the absorber and/or reactor and transported for further treatment or for use The insoluble sulfur, e g S_β or other forms of polymerized sulfur, is withdrawn from the polymerization reactor as a precipitate in the reaction solution, is separated from solution by filtration, centrifugation or other means known in the art, is washed to remove the polar organic solvent, dissolved hydroquinone, any unreacted quinone and complexing agent, and is dried and may be subsequently melted to a liquid form In accordance with the present invention, the insoluble sulfur is washed with a wash solvent The wash solvent is any liquid hydrocarbon which soiubilizes the reaction solution, i e the polar organic solvent having quinone, hydroquinone, and complexing agent dissolved therein This wash solvent has a boiling point of at least about 50° C, preferably at least about 100° C, and most preferably at least about 150° C below that of the polar organic solvent Preferred wash solvents are oxygenated hydrocarbons, such as, acetone, 3- pentanone, or mixtures thereof The reaction solution which is remaining after sulfur removal and which contains hydroquinone, any unreacted quinone, complexing agent, solvent, and unreacted compounds from the feed gas such as H₂S, COS, CS₂, CO₂, mercaptans and unrecovered sulfur, is heated to and maintained at a temperature of from about 70^° C to about 220^' C and at a pressure of from about 0 01 to about 2 0 atmospheres to convert COS, CS₂ mercaptans and unrecovered sulfur to H₂S The reaction solution is then fed to a flash tank or fractionator where substantially all unreacted feed gas constituents including water, CO, and/or low molecular weight hydrocarbons are removed from solution, separated, and recovered as products The separation of unreacted feed gas constituents which have been removed from the reaction solution via the flash tank or fractionator can be effectuated by any suitable means as will be evident to a skilled artisan For example, a three phase separator can be utilized wherein water having C0₂ dissolved therein is removed from the bottom of the separator while liquid low molecular weight hydrocarbons having C0₂ dissolved therein are also removed from the separator The remaining gas which consists primarily of unreacted H₂S is recycled to the absorber and/or polymerization reactor with the incoming feed gas The reaction solution which is withdrawn from the flash tank or fractionator is further heated to from about 220° C to about 350° C at a pressure sufficient to prevent solvent boiling The heated solution is then fed to a dehydrogenation reactor where the hydroquinone is catalytically or thermally converted to quinone and hydrogen gas (H₂) under the temperature pressure conditions stated above Quinone in its initial form is withdrawn from the dehydrogenation reactor dissolved with the complexing agent in the polar organic solvent and is recycled to the H,S-quιnone absorber, while the H gas is recovered as a commercial product

The presence of a complexing agent in the remaining reaction solution, i e that solution which is withdrawn from the polymerization reactor, which has had sulfur removed therefrom, and which contains hydroquinone, any unreacted quinone, complexing agent, solvent, and unreacted compounds from the feed gas, is also desirable As previously mentioned, after being heated to from about 70° C to about 220° C , flashed, and further heated to from about 220° C to about 350° C , the heated solution is then fed to a dehydrogenation reactor where the hydroquinone is catalytically or thermally converted to quinone and hydrogen gas (H₂) under the temperature pressure conditions stated above Dehydrogenation of hydroqumones using metal supported catalysts may cause hydrogenolysis which results in the undesirable production of water and by-products In the case of anthraqunones, these by-products are anthrones and/or anthranols Applicants have discovered that the presence of a complexing agent in the reaction solution fed to the dehydrogenation reactor results in aπ unexpected and marked increase in the selectivity of hydroquinone to quinone and hydrogen product, and thus, the attendant decrease in unwanted hydrogenolysis by-products The molar ratio of complexing agent to total quinones, i e hydroquinone and any unreacted quinone, in the remaining reaction solution within the dehydrogenation reactor is about 1 50 to about 2 1 , and more preferably about 1 10 to about 1 1

Further, the addition of water to the polar organic solvent prior to the sulfur production stage of the process of the present invention results in increased hydrogen product selectivity in the dehydrogenation stage of the process Although not completely understood, it is believed that water addition prior to the sulfur production stage substantially eliminates the production of the free radicals at this stage which are necessary for anthraπol production in the later dehydrogenation stage Anthrone production is effectively eliminated by operating at temperatures less than about 265° C

The following example demonstrates the practice and utility of the present invention, but are not to be construed as limiting the scope thereof

Example 1

A solution of N,N-dιmethylacetamιde (DMAC) having 15 wt% t-butyl anthraquinone (TBAQ) dissolved therein has a complexing agent further incorporated therein at a complexing agent/TBAQ molar ratio of 1 8 Several complexing agents having differing pK_f. values are incorporated into separate solutions of DMAC and TBAQ and are contacted with a hydrogen sulfide containing gas in a suitable reactor at a temperature of 70° C and at a H₂S partial pressure of about 3 55 atmospheres The complexing agents utilized are methylacetamide (MAC), pyridine (PY), diethylmethylamine (DEMA), N- methyl-2-pyrrolιdιnone (NMP) and methyldiethanolamine (MDEA) Mechanism 3a occurs in about 10 to 20 minutes and mechanism 3b then follows and continues up to about 60 minutes of reaction time The rate constants for mechanisms 3a and 3b are calculated and the results are illustrated in FIG 1 The rate constant for mechanism 3a exponentially increases with decreasing complexing agent pK,, value Example 2

T-butyl anthraquinone (TBAQ) is added to dimethylacetamide (DMAC) in an amount of 15 wt%. Diethylmethylamine (DEMA), pyridine (PY) or dimethylacetamide (DMAC) are also added to the solution as a complexing agent in a molar ratio of complexing agent to TBAQ of 1/8. The separate solutions are maintained in suitable reactors at different temperatures of from 0° C. to 70° C. and at a H₂S partial pressure of 3.55 atmospheres. Reaction rate constants are calculated at each reaction temperature for mechanisms 3a and 3b assuming first order kinetics in TBAQ conversion The calculated rate constants are correlated to reaction temperature according to the Arrhenius model from which activation energies are calculated. As graphically represented in FIG. 2, these results illustrate that as complexing agent pK„ decreases from the base case where DMAC is both the solvent and complexing agent, the activation energies for mechanisms 3a and 3b linearly decrease. This decrease is slightly more pronounced for mechanism 3b than for mechanism 3a.

Example 3

Varying amounts of diethylmethylamine (DEMA) complexing agent are added to N,N dimethylacetamide (DMAC) solvent which contains 15 wt% t-butyl anthraquinone (TBAQ) The resultant solutions are maintained in a suitable reactor at a temperature of 20° C. and at a H₂S partial pressure of 3.55 atmospheres Total TBAQ conversion after the end of conversion mechanism 3a, i.e., 6-11 minutes or after 11 minutes of total reaction time is measured. As illustrated in FIG. 3, these results indicate that the conversion of t-butyl anthraquinone (TBAQ) to t-butyl anthrahydroquinone (HTBAQ) increases with increasing complexing agent/TBAQ ratio. Extrapolation of the data depicted in FIG. 3 indicates that a 100% conversion of TBAQ to HTBAQ will occur in 6-11 minutes for a DEMA/TBAQ molar ratio of about 0.75.

Example 4

A gaseous mixture of hydrogen sulfide and carbon dioxide is introduced into a laboratory reactor together with 15 wt% t-butyl anthraquinone (TBAQ) in a N,N-dιrnethylacetamιde (DMAC) solution This solution also contains diethylmethylamine (DEMA) as a complexing agent in a ratio of 1 mole of DEMA per 8 moles of TBAQ The reactor is operated at a constant temperature of about 20° C and at a total pressure of from about 0 85 to 3 55 atmospheres Three gaseous feeds having varying H₂S/C0₂ molar ratios of 100/0, 49 5\50 5 and 19 8/80.2 are introduced separately into the reactor and the reaction rate constants for mechanisms 3a and 3b are calculated using a reaction modei which is first order in TBAQ concentration The results are illustrated graphically in Fig 4 and indicate that the reaction rate constants using a mixture of hydrogen sulfide and carbon dioxide in the reactor are about twice the rate constants achieved with a pure hydrogen sulfide feed This result is valid for carbon dioxide/anthraquinone molar ratios in excess of 0 05 This result is also achieved at relatively low partial pressures of hydrogen sulfide, e g 0 68 atmospheres, thereby reducing cost of gas compression

Example 5 Gamma-butyrolactone (GBL) having 15 wt% t-butyl anthraquinone (TBAQ) dissolved therein is contacted with a hydrogen sulfide containing gas in a suitable reactor at a temperature of 20° C and at a H₂S partial pressure of 3 17 atmospheres Gamma-butyrolactone has a polarity of 4 17 Debye units The reaction is allowed to proceed for one hour and the amount of t-butyl anthraquinone (TBAQ) which is converted to t-butyl anthrahydroquinone (HTBAQ) is measured TBAQ conversion was zero This result indicates that utilizing a solvent having a polarity above 3 0 Debye units in the absence of a complexing agent does not necessarily result in acceptable TBAQ conversion

Example 6

T-butyl anthraquinone (TBAQ) is added to N,N-dιmethylacetamιde (DMAC) in aπ amount of 15 wt% Diethylmethylamine (DEMA) is also added to the solution as a complexing agent in a molar ratio of complexing agent to TBAQ of 1/8 The solution is separately maintained in suitable reactors at a temperature of 20° C and at varying H₂S partial pressures The results are illustrated in FIG 5 S₈ recovery is essentially constant for H,S partial pressures above about 1.52 atmospheres while S_β recovery increases for H₂S partial pressures below about 1 52 atmospheres to 100% at a H₂S partial pressure of 068 atmospheres. Thus, the reduced H₂S partial pressure at which the process of the present invention can be operated results in increased S, recovery Example 7

Varying amounts of pyridine complexing agent are added to separate dehydrogenation feeds containing t-butyl anthrahydroquinone and introduced to a reactor wherein the anthrahydroquinone is dehydrogenated to anthraquinone and hydrogen in the presence of a platinum catalyst. Dehydrogenation is carried out in the reactor at a total pressure of about 4 35 to about 5 71 atmospheres and at a temperature of 265° C when the Si0₂ catalyst support is used and 285° C. when the quartz catalyst support is used Each feed is reacted for approximately 1 05 minutes The results are illustrated graphically in Fig 6 and indicate that the presence of a complexing agent in the reaction solution feed to the dehydrogenation reactor in a ratio of complexing agent to total quinones, i e anthrahydroquinone and any unreacted anthraquinone, of about 1 :50 to about 2.1 and preferably about 1 10 to about 1 1 results in an unexpected and marked increase in the selectivity of anthrahydroquinone to anthraquinone and hydrogen Thus, unwanted hydrogenolysis by-products, such as anthrones and/or anthranols, are also decreased

Example 8 Pyridine, 2,4 lutidine, and diethylmethylamine (DEMA) are each added to separate dehydrogenation feeds which contain 18 75 wt% t-butyl anthrahydroquinone (H₂TBAQ) as complexing agents in the amount of 1 mole of complexing agent per 8 moles of total anthraqumones, i e t-butyl anthraquinone (TBAQ) and t-butyl anthrahydroquinone Pyridine, 2,4 lutidine, and DEMA have pK„ values of 8 8, 7 0 and 3 6, respectively Each dehydrogenation feed is introduced to a reactor wherein the anthrahydroquinone is dehydrogenated to anthraquinone and hydrogen in the presence of a platinum catalyst on a SiO_: support Dehydrogenation is carried out in the reactor at a total pressure of about 4 21 atmospheres and at a temperature of 265° C Each feed is reacted for approximately a 1 minute residence time The selectivity of t-butyl anthrahydroquinone to hydrogen and t-butyl anthraquinone is 74%, 88%, and 100% when pyridine, 2,4 lutidine, and DEMA, respectively, are used as the complexing agent in the feed to the dehydrogenation reactor These results which are illustrated graphically in Fig 7 indicate that the pK, of the complexing agent in the reaction solution feed to the dehydrogenation reactor has an significant effect in increasing the selectivity of anthrahydroquinone to anthraquinone and hydrogen Thus, unwanted hydrogenolysis by-products, such as anthrones and/or anthranols, are also decreased Example 9

A solution is formed from 24 50 wt% t-butyl anthraquinone (TBAQ), 73 51 wt% π-methyl-2-pyrrolιdιnone (NMP), 1 67 wt% water and 0 32 wt% diethylmethylamine (DEMA) and is pumped into the bottom of a reactor containing four H,S injection points equally spaced along the height of the reactor A separate updraft turbine mixer which rotates at 200 rpm is positioned within the reactor at each injection point Three separate tests are conducted in which the total amount of H₂S introduced into the reactor is sufficient to convert 90% of the TBAQ into t-butyl anthrahydroquinone (H₂TBAQ) and sulfur The entire amount of H₂S is introduced into the reactor solely via the first injection point in the first test In the second test, one half of the total amount of H₂S is introduced into the reactor via each of the first and third injection points, while in the third test, one fourth of the total amount of H₂S is introduced into the reactor via each of the four injection points In each test, the solution is pumped at a rate sufficient to create a 10 minute residence time within the reactor prior to the solution exiting the top thereof The temperature and pressure of the reactor is maintained at 65^° C and 1 5 atmospheres in all tests

In all three tests, the effluent solution from the reactor is fed to a second reactor where the effluent is completely back mixed, held at 20^° C and 1 0 atmosphere for a residence time of 20 minutes Sulfur (S„) crystallization and precipitation occurs in this second reactor The reaction solution is removed from the second reactor and filtered to remove sulfur The amount of S, thus removed is compared to the total amount of S atoms formed in the reaction of TBAQ and H,S These results indicate that the use of 4 injection stages or points for introduction of H₂S into the first reactor was critical for significantly increasing the amount of TBAQ converted into HTBAQ in the first reactor (FIG. 8) and the amount of S atoms converted into S, for precipitation in the second reactor (FIG. 9). Example 10

A solution of 2.47 wt% benzoquinone, 24.13 wt% t-butyl anthraquinone(TBAQ), 1.01 wt% diethylmethylamine (DEMA) and 72.39 wt% N-methyl-2-pyrrolidinone (NMP) is introduced into a reactor and maintained therein at a temperature of 21 ^° C. and a pressure of 1.5 atmospheres. DEMA is present in the solution as a complexing agent in a ratio of 0.1 moles of DEMA per mole of total quinones. While in the reactor, the solution is contacted with a hydrogen sulfide containing gas for 0.3 minutes and the temperature increases to 46.7^° C. in the reactor. The solution is cooled within the reactor to 20^° C. in 8.7 minutes. This reaction results in a 83% conversion of TBAQ to t- butyl anthrahydroquinone and a 67% conversion of benzoquinone to beπzohydroquinone.

A solution of 8.75 wt.% benzoquinone, 0.73 wt% diethylmethylamine (DEMA) and 90.52 wt% N-methyl-2-pyrrolidinone (NMP) is introduced into a reactor under conditions which are identical to those set forth above in this Example. DEMA is present in the solution as a complexing agent in a ratio of

0.25 moles of DEMA per mole of benzoquinone. The solution is contacted with a hydrogen sulfide containing gas in the reactor for 0.3 minutes and the temperature increases to 46.7^" C. in the reactor. The solution is cooled in the reactor to 20^° C. in 8.7 minutes. This reaction results in a 78% conversion of benzoquinone to benzohydroquinone.

A solution of 18.03 wt% 1 ,4 napthaquinone, 1.24 wt% diethylmethylamine (DEMA) and 80.73 wt% N-methyl-2-pyrrolidinone (NMP) is introduced into a reactor under conditions which are identical to those set forth above in this Example. DEMA is present in the solution as a complexing agent in a ratio of 0.125 moles of DEMA per mole of 1 ,4 napthaquinone. The solution is contacted with a hydrogen sulfide containing gas in the reactor for 0.3 minutes and the temperature increases to 46. T C. in the reactor. The solution is cooled in the reactor to 20° C in 8 7 minutes This reaction results in a 70% conversion of 1 4 napthaquinone to 1 ,4 napthahydroquinone

The foregoing examples demonstrate that benzoquinones and napthaqumones are equally as suitable as anthraqumones for use in the process of the present invention

Example 11 A natural gas feed stream containing 90 41 mole % methane, 2 51 mole % H₂S, 1 81 mole % C0₂, 4 92 mole % natural gas liquid (NGL) and 0 35 mole % water is introduced into the bottom of an absorber operating at 49 ° C and 43 atmospheres The composition of the NGL is 61 94 mole % ethane, 1567 mole

% propane, 15 95 mole % butanes, 5 69 mole % pentanes and 0 75 mole % hexanes Also, a recycle gas stream with a composition of 60 49 mole % methane, 8 38 mole % H₂S, 10 03 mole % C0₂, 20 79 mole % NGL, and 0 31 mole % water is introduced into the bottom of the absorber The molar ratio of the recycle gas stream to the feed gas stream is 0 0444

A recycle absorbent having a composition of 77 91 mole % N-methyl-2- pyrrolιdιnone(NMP), 7 05 pyrιdιne(PY), 7 27 mole % t-amyl anthraquinone (TAAQ), 0 18 mole % t-amyl anthrahydroquinone (H₂TAAQ), 7 45 mole % water, 0 05 mole % H₂, and 0 09 mole % H₂S is introduced into the top of the absorber in an amount such that 1 mole of TAAQ plus H₂TAAQ is introduced per mole of total H₂S in the feed gas plus the H₂S in two recycle gas streams The H₂S in the feed gas reacts with a portion of the TAAQ to produce H₂TAAQ and sulfur atoms

A product gas is withdrawn from the top of the absorber This stream contains 93 40 moie % methane, 0 05 mole % NMP plus PY, 0 04 mole % water, 0 03 mole % H₂, 1 77 mole % C0₂, and 4 71 mole % NGL Essentially all of the methane in the feed gas is recovered to the product gas, and essentially all of the H₂S is removed from the feed gas and is converted into sulfur Recycle absorbent is removed from the absorber and introduced into polymerization reactor where additional reaction between H₂S and TAAQ occurs and sulfur atoms are polymerized into insoluble S₈ This reactor operates at 30° C and 1 7 atmospheres The resulting slurry of S₈ and recycle absorbent is removed from the polymerization reactor and introduced into a filter where essentially all of the H₂S in the feed gas is recovered as S₈ Also, a gas phase is removed from the polymerization reactor by a compressor In this step, the gas phase is compressed to 42 atmospheres and cooled to 49° C A liquid NGL product is then removed from this compressed gas phase The amount of this NGL product is 7 18 mole% of the total NGL in the feed gas Also, C0₂ is removed in this step at 5 1 mole% of that in the feed gas The remaining gas is then recycled back to the absorber As discussed above, the molar ratio of this gas to the feed gas is 0 0444 The recycle absorbent from the above filtration step is then introduced into a fractionation unit operating at 2 0 atmospheres and temperatures from 149 to 210° C A water and acid gas mixture is removed from the top of this fractionation unit The water, which equals 90 mole% of the water in the feed gas, is then recovered from this acid gas as a product The acid gas is then recycled to the polymerization reactor The molar ratio of this gas to the feed gas is 0 0366 The composition of this acid gas is 2 01 mole % methane, 0 13 mole % NMP, 1065 mole % water, 58 39 mole % H₂S, 3 38 mole % C0₂, 25 44 mole % NGL

Recycle absorbent essentially free of any unreacted H₂S is removed from the bottom of the fractionation unit and introduced into a dehydrogenation reactor where the H₂TAAQ is converted back into TAAQ and H₂ product This reaction occurs at 250° C and 47 atmospheres The catalyst used contains Pt on a Sι0₂ support The H plus recycle absorbent is removed from the dehydrogenation reactor and cooled to 49° C H₂ is then recovered from the recycle absorbent as a product at molar ratio of 0 9214 to the H₂S in the feed gas The absorbent is then cooled to 49° C and recycled back to the absorber to start its cycle over again

Example 12 A natural gas feed stream containing 71 92 mole % methane, 19 95 mole % H₂S, 1 43 mole % C0₂, 3 91 mole % natural gas liquid (NGL) and 2 79 mole

% water is introduced into the bottom of an absorber operating at 36 ° C and 42 atmospheres The composition of the NGL is 61 86 mole % ethane, 15 72 mole % propane 15 98 mole % butanes, 5 67 mole % pentanes and 0 77 moie % hexanes. Also, a recycle gas stream with a composition of 29.54 moie % methane, 3.59 mole % H₂S, 35.63 mole % C0₂, 30.90 mole % NGL, and 0.34 mole % water is introduced into the bottom of the absorber. The molar ratio of the recycle gas stream to the feed gas stream is 1.008. A recycle absorbent having a composition of 80.50 mole % N-methyl-2- pyrrolidinone(NMP), 7.30 pyridine(PY), 7.49 mole % t-amyl anthraquinone (TAAQ), 0 14 mole % t-amyl anthrahydroquinone (H₂TAAQ), 4.43 moie % water, 0.05 mole % H₂, and 0.09 mole % H₂S is introduced into the top of the absorber in an amount such that 1.34 moles of TAAQ plus H₂TAAQ is introduced per mole of total H₂S in the feed gas plus the H₂S in two recycle gas streams The H₂S in the feed gas reacts with a portion of the TAAQ to produce H₂TAAQ and sulfur atoms.

A product gas is withdrawn from the top of the absorber. This stream contains 95.77 mole % methane, 0.04 mole % NMP, plus PY, 0.04 mole % water, 0.48 mole % H₂, 0.53 mole % C0₂, and 3.14 mole % NGL. Essentially all of the methane in the feed gas is recovered to the product gas, and essentially all of the H₂S is removed from the feed gas and is converted into sulfur

Recycle absorbent is removed from the absorber and introduced into a polymerization reactor where additional reaction between H₂S and TAAQ occurs and sulfur atoms are polymerized into insoluble S₈. This reactor operates at 30° C and 1.7 atmospheres. The resulting slurry of S₈ and recycle absorbent is removed from the polymerization reactor and introduced into a filter where essentially all of the H₂S in the feed gas is recovered as S₈. Also, a gas phase is removed from the polymerization reactor by a compressor. In this step, the gas phase is compressed to 42 atmospheres and cooled to 49° C. A liquid NGL product is then removed from this compressed gas phase. The amount of this NGL product is 91.7 mole% of the propane through hexane components initially present in the feed gas. Also, C0₂ is removed in this step at 27 4 mo!e% of that in the feed gas The remaining gas is then recycled back to the absorber. As discussed above, the molar ratio of this gas to the feed gas is 1.008. The recycle absorbent from the above filtration step is then introduced into a fractionation unit operating at 2.0 atmospheres and temperatures from 71° C to 210° C. A water and acid gas mixture is removed from the top of this fractionation unit. The water, which equals 99 mole% of the water in the feed gas, is then recovered from this acid gas as a product. The acid gas is then recycled to the polymerization reactor. The molar ratio of this acid gas to the feed gas is 0.4241. The acid gas consists of 1.26 mole% methane, 0.08 mole% NMP, 9.37 mole% water, 54.48 mole% H₂S, 15.41 mole% C0₂, 19.40 mole% NGL. Recycle absorbent essentially free of any unreacted H₂S is removed from the bottoms of the fractionator and introduced into a dehydrogenation reactor where the H₂TAAQ is converted back into TAAQ and H₂ product. This reaction occurs at 250° C and 4.7 atmospheres. The catalyst used contains Pt on a Si0₂ support. The H₂ plus recycle absorbent is removed from the dehydrogenation reactor and cooled to 49° C. H₂ is then recovered from the recycle absorbent as a product at molar ratio of 0.9215 to the H₂S in the feed gas. The absorbent is then cooled to 49° C and recycled back to the absorber.

Example 13 T-butyl anthraquinone (TBAQ) is added to N-methyl-2-pyrrolidinone (NMP) in an amount of 25 wt%. Pyridine (PY) is also added to the solution as a complexing agent in a molar ratio of complexing agent to TBAQ of 1/1. Varying amounts of water are added to separate portions of the solution. Each portion of the solution is contacted with hydrogen sulfide containing gas in a suitable reactor at a temperature of 20° C and at a H₂S partial pressure of 1.5 atmospheres for 2 hours. The amount of S„ recovered is determined by weighing the sulfur which is precipitated out of the solution removed from the reactor. The results are graphically illustrated in FIG. 10. As illustrated in FIG. 10, the amount of S, recovered, which is expressed as the weight % of total sulfur formed in the reactor, increases with increasing amounts of water which are absorbed into the solution prior to or during the sulfur production stage of the process, i.e. during the conversion of hydrogen sulfide and anthraquinone to sulfur and anthrahydroquinone. Example 14

A dehydrogenation feed of N-methyl-2-pyrrolιdιnone (NMP) containing 25 wt.% t-butyl anthrahydroquinone (HTBAQ) is introduced to a reactor wherein the t-butyl anthrahydroquinone is dehydrogenated to t-butyl anthraquinone (TBAQ) and hydrogen in the presence of a platinum catalyst. Dehydrogenation is carried out in the reactor at varying hydrogen pressures of about 2.31 to about 6 12 atmospheres to prevent solution boiling at the varying dehydrogenation temperatures of from about 220° C to about 290° C Two separate feeds are reacted under these parameters Water is not added to one feed and is added to another feed prior to sulfur production in an amount of about 1 mole of water per mole of TBAQ. Pyridine (PY) is added as a complexing agent to the latter feed in the amount of one mole of pyridine per mote of TBAQ. Each feed is reacted for approximately 1 minute. The results which are illustrated graphically in Fig. 11 indicate that H₂TBAQ selectivity to hydrogen and TBAQ can be increased to 100% below 225° C if water is added to the NMP solvent prior to the sulfur production stage of the process or absorbed from a gaseous feed stream containing H₂S Thus, unwanted hydrogenolysis by-products, such as anthrones and/or anthranols, can be effectively eliminated.

While the foregoing preferred embodiments of the invention have been described and shown, it is understood that the alternatives and modifications, such as those suggested and others, may be made thereto and fall within the scope of the invention

Claims

We claim 1 A process of removing hydrogen sulfide and other components from a gas comprising (a) contacting a gaseous stream containing hydrogen sulfide with a polar organic solvent having a quinone dissolved therein, wherein substantially ali of said hydrogen sulfide and at least a portion of a second component of said gaseous stream which is selected from the group consisting of water, low molecular weight hydrocarbons, carbon dioxide or mixtures thereof are dissolved in said polar organic solvent. 2 The process of claim 1 further comprising: (b) reacting said hydrogen sulfide with said quinone to produce sulfur and a hydroquinone in said solvent. 3 The process of claim 2 further comprising; (c) separating said sulfur produced in step (b) from said polar organic solvent 4 The process of claim 3 further comprising: (d) dehydrogenatmg said hydroquinone to said quinone and hydrogen 5 The process of claim 1 wherein said low molecular weight hydrocarbon is ethane, propane, butanes, pentanes, hexanes or mixtures thereof 6 The process of claim 2 wherein steps (a) and (b) are conducted within a reactor. 7 The process of claim 2 wherein step (a) is conducted within an absorber and said polar organic solvent having substantially all of said hydrogen sulfide and said at least a portion of said second component dissolved therein is transported to a reactor wherein step (b) is conducted 8 The process of claim 1 wherein said polar organic solvent has a complexing agent dissolved therein 9 The process of claim 3 further comprising (e) removing said second component of said gaseous stream from said polar organic solvent and recovering said second component as at least one product 10 The process of claim 9 wherein said polar organic solvent contains unrecovered sulfur not separated from said polar organic solvent in step (c) and other sulfur compounds which are initially contained in said gaseous stream and which are dissolved in said polar organic solvent in step (a), said unrecovered sulfur and said other sulfur compounds being converted in step (e) to hydrogen sulfide 1 1 The process of claim 10 wherein said other sulfur compounds are COS, CS, mercaptans or mixtures thereof 12 A process of decomposing hydrogen sulfide to sulfur and hydrogen comprising (a) contacting a gaseous stream containing hydrogen sulfide with a polar organic solvent having a quinone dissolved therein, wherein substantially all of said hydrogen sulfide and at least a portion of a second component of said gaseous stream which is selected from the group consisting of water, low molecular weight hydrocarbons, carbon dioxide or mixtures thereof are dissolved in said polar organic solvent, (b) reacting said hydrogen sulfide with said quinone to produce sulfur and a hydroquinone in said solvent, (c) separating said sulfur produced in step (b) from said polar organic solvent, and (d) dehydrogenatmg said hydroquinone to said quinone and hydrogen 13 The process of claim 12 wherein said low molecular weight hydrocarbon is ethane, propane butanes, pentanes, hexanes or mixtures thereof 14 The process of claim 12 wherein steps (a) and (b) are conducted within a reactor 15 The process of claim 12 wherein step (a) is conducted within an absorber and said polar organic solvent having substantially all of said hydrogen sulfide and said at least a portion of said second component dissolved therein is transported to a reactor wherein step (b) is conducted 16 The process of claim 12 wherein said polar organic solvent has a complexing agent dissolved therein 17 The process of claim 12 further comprising (e) removing said second component of said gaseous stream from said polar organic solvent and recovering said second component as at least one product 18 The process of claim 17 wherein said polar organic solvent contains unrecovered sulfur not separated from said polar organic solvent in step (c) and other sulfur compounds which are initially contained in said gaseous stream and which are dissolved in said polar organic solvent in step (a), said unrecovered sulfur and said other sulfur compounds being converted in step (e) to hydrogen sulfide 19 The process of claim 18 wherein said other sulfur compounds are COS, CS, mercaptans or mixtures thereof 20 All inventions described herein