WO1997018028A1 - Procede de traitement de gaz - Google Patents

Procede de traitement de gaz Download PDF

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Publication number
WO1997018028A1
WO1997018028A1 PCT/US1996/015314 US9615314W WO9718028A1 WO 1997018028 A1 WO1997018028 A1 WO 1997018028A1 US 9615314 W US9615314 W US 9615314W WO 9718028 A1 WO9718028 A1 WO 9718028A1
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WIPO (PCT)
Prior art keywords
organic solvent
polar organic
hydrogen sulfide
sulfur
quinone
Prior art date
Application number
PCT/US1996/015314
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English (en)
Inventor
Mark A. Plummer
John J. Waycuilis
Original Assignee
Marathon Oil Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Marathon Oil Company filed Critical Marathon Oil Company
Priority to CA002230849A priority Critical patent/CA2230849A1/fr
Priority to AU71176/96A priority patent/AU7117696A/en
Publication of WO1997018028A1 publication Critical patent/WO1997018028A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/06—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/52—Hydrogen sulfide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/02—Preparation of sulfur; Purification
    • C01B17/04—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides
    • C01B17/05—Preparation of sulfur; Purification from gaseous sulfur compounds including gaseous sulfides by wet processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/80—Organic bases or salts
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

Definitions

  • 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.
  • 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.
  • natural gas which is produced from subterranean formations often contains similar gases to those gaseous by-products listed above.
  • U. S. Patent No. 3,039,251 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. 3,039,251 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.
  • 4,359,450 discloses the removal of H 2 S CO 2 and COS from gaseous streams characterized by the reaction of H 2 S to crystalline or solid sulfur, the abso ⁇ tion of C0 2 and COS, the desorption of C0 2 and COS, the hydrolysis of COS, and the recovery of H 2 S.
  • 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 CO 2 , COS and H 2 S, such as propylene carbonate, N-methyl pyrrolidone, and sulfolane.
  • 3,773,896 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
  • 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
  • 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
  • these gaseous by-products were oxidized by common oxidation processes, such as the
  • 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
  • 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.
  • 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.
  • a process 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
  • 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 avail 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
  • TBAQ t-butyl anthraquinone
  • H BAQ t-butyl anthrahydroqumone
  • FIG 3 is a graph which depicts the conversion of t-butyl anthraquinone (TBAQ) to t-butyl anthrahydroquinone (H 2 TBAQ) 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,
  • HTBAQ t-butyl anthrahydroquinone
  • TBAQ t-butyl anthraquinone
  • 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,
  • HTBAQ t-butyl anthrahydroquinone
  • 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 (H 2 S) into the H 2 S-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 (H 2 S) into the H,S-TBAQ reactor
  • S. sulfur
  • 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.
  • 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
  • TBAQ t-butyl anthraquinone
  • 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
  • the gaseous feed containing hydrogen sulfide (H 2 S) is contacted in an H 2 S absorber with a polar organic solvent having a quinone and a H 2 S 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 C 2 - C 6 , and/or carbon dioxide present in the gaseous feed stream
  • 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
  • the absorber and polymerization reactor may be a single reaction vessel, for example a stirred tank, in which both functions are performed
  • 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 H 2 S 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
  • sulfanes In the conversion of quinone to hydroquinone in the H 2 S absorber and/or polymerization reactor, sulfanes (i e , H 2 S 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
  • 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-pyrol ⁇ d ⁇ none,
  • 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 )
  • selection of a suitable complexing agent is based in part upon the ability of the complexing agent to react with H 2 S 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
  • 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
  • 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 H 2 S
  • 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
  • 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
  • the reaction solution i e the polar organic solvent having a suitable quinone, complexing agent and hydrogen sulfide dissolved therein, is maintained in the H 2 S 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 H 2 S 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
  • 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
  • any suitable means as will be evident to a skilled artisan, such as by means of a three phase separator
  • 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
  • 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 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 ⁇ or other forms of polymerized sulfur
  • 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,
  • a solution of N,N-d ⁇ methylacetam ⁇ de (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 .
  • T-butyl anthraquinone (TBAQ) is added to dimethylacetamide (DMAC) in an amount of 15 wt%.
  • DEMA diethylmethylamine
  • PY pyridine
  • DMAC dimethylacetamide
  • the separate solutions are maintained in suitable reactors at different temperatures of from 0° C. to 70° C. and at a H 2 S 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.
  • FIG. 2 these results illustrate that as complexing agent pK Von 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.
  • Varying amounts of diethylmethylamine (DEMA) complexing agent are added to N,N dimethylacetamide (DMAC) solvent which contains 15 wt% t-butyl anthraquinone (TBAQ)
  • DEMA diethylmethylamine
  • DMAC N,N dimethylacetamide
  • TBAQ t-butyl anthraquinone
  • the resultant solutions are maintained in a suitable reactor at a temperature of 20° C. and at a H 2 S 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.
  • 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
  • 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-d ⁇ rnethylacetam ⁇ de (DMAC) solution
  • DMAC N,N-d ⁇ rnethylacetam ⁇ de
  • DEMA diethylmethylamine
  • 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 H 2 S/C0 2 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
  • T-butyl anthraquinone (TBAQ) is added to N,N-d ⁇ methylacetam ⁇ de (DMAC) in a ⁇ 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
  • DMAC N,N-d ⁇ methylacetam ⁇ de
  • DEMA Diethylmethylamine
  • S 8 recovery is essentially constant for H,S partial pressures above about 1.52 atmospheres while S ⁇ recovery increases for H 2 S partial pressures below about 1 52 atmospheres to 100% at a H 2 S partial pressure of 068 atmospheres.
  • the reduced H 2 S 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 Si0 2 catalyst support is used and 285° C.
  • Example 8 Pyridine, 2,4 lutidine, and diethylmethylamine (DEMA) are each added to separate dehydrogenation feeds which contain 18 75 wt% t-butyl anthrahydroquinone (H 2 TBAQ) 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 cogn 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
  • a solution is formed from 24 50 wt% t-butyl anthraquinone (TBAQ), 73 51 wt% ⁇ -methyl-2-pyrrol ⁇ d ⁇ none (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 H 2 S introduced into the reactor is sufficient to convert 90% of the TBAQ into t-butyl anthrahydroquinone (H 2 TBAQ) and sulfur
  • the entire amount of H 2 S is introduced into the reactor solely via the first injection point in the first test
  • one half of the total amount of H 2 S is introduced into the reactor via each of the first and third injection points
  • one fourth of the total amount of H 2 S is introduced
  • 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 diethylmethylamine
  • NMP N-methyl-2-pyrrolidinone
  • 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
  • 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
  • Example 11 A natural gas feed stream containing 90 41 mole % methane, 2 51 mole % H 2 S, 1 81 mole % C0 2 , 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
  • a recycle gas stream with a composition of 60 49 mole % methane, 8 38 mole % H 2 S, 10 03 mole % C0 2 , 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 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 % H 2 , 1 77 mole % C0 2 , 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 H 2 S 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 H 2 S and TAAQ occurs and sulfur atoms are polymerized into insoluble S 8
  • This reactor operates at 30° C and 1 7 atmospheres
  • the resulting slurry of S 8 and recycle absorbent is removed from the polymerization reactor and introduced into a filter where essentially all of the H 2 S in the feed gas is recovered as S 8
  • a gas phase is removed from the polymerization reactor by a compressor In this step,
  • Recycle absorbent essentially free of any unreacted H 2 S is removed from the bottom of the fractionation unit and introduced into a dehydrogenation reactor where the H 2 TAAQ is converted back into TAAQ and H 2 product This reaction occurs at 250° C and 47 atmospheres
  • the catalyst used contains Pt on a S ⁇ 0 2 support
  • the H plus recycle absorbent is removed from the dehydrogenation reactor and cooled to 49° C H 2 is then recovered from the recycle absorbent as a product at molar ratio of 0 9214 to the H 2 S 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 % H 2 S, 1 43 mole % C0 2 , 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.
  • a recycle gas stream with a composition of 29.54 moie % methane, 3.59 mole % H 2 S, 35.63 mole % C0 2 , 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 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 % H 2 , 0.53 mole % C0 2 , 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 H 2 S 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 H 2 S and TAAQ occurs and sulfur atoms are polymerized into insoluble S 8 .
  • This reactor operates at 30° C and 1.7 atmospheres.
  • the resulting slurry of S 8 and recycle absorbent is removed from the polymerization reactor and introduced into a filter where essentially all of the H 2 S in the feed gas is recovered as S 8 .
  • 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.
  • C0 2 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.
  • 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% H 2 S, 15.41 mole% C0 2 , 19.40 mole% NGL.
  • Recycle absorbent essentially free of any unreacted H 2 S is removed from the bottoms of the fractionator and introduced into a dehydrogenation reactor where the H 2 TAAQ is converted back into TAAQ and H 2 product. This reaction occurs at 250° C and 4.7 atmospheres.
  • the catalyst used contains Pt on a Si0 2 support.
  • the H 2 plus recycle absorbent is removed from the dehydrogenation reactor and cooled to 49° C.
  • H 2 is then recovered from the recycle absorbent as a product at molar ratio of 0.9215 to the H 2 S in the feed gas. The absorbent is then cooled to 49° C and recycled back to the absorber.
  • 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 H 2 S partial pressure of 1.5 atmospheres for 2 hours. The amount of S stress 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.
  • 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
  • NMP N-methyl-2-pyrrol ⁇ d ⁇ none
  • HTBAQ t-butyl anthrahydroquinone
  • 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.
  • H 2 TBAQ 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 H 2 S
  • unwanted hydrogenolysis by-products such as anthrones and/or anthranols, can be effectively eliminated.

Abstract

Procédé permettant d'éliminer l'hydrogène sulfuré et d'autres constituants, tels que de l'eau, des hydrocarbures de faible poids moléculaire, et du dioxyde de carbone, qui sont présents dans un flux d'alimentation gazeux et de convertir l'hydrogène sulfuré en soufre et en hydrogène élémentaires. Selon ledit procédé, un flux d'alimentation gazeux contenant de l'hydrogène sulfuré et d'autres constituants est mis en contact avec un solvant organique polaire possédant une quinone et un agent complexant dissous dans ledit solvant. L'agent complexant doit avoir une valeur pKb inférieure à environ 13,0. La réaction de l'hydrogène sulfuré présent dans le flux d'alimentation gazeux avec la quinone entraîne une conversion accrue de la quinone en hydroquinone à des températures de réacteur et à des pressions partielles de H2S faibles, ainsi qu'une récupération accrue de soufre. De plus, la présence d'un agent complexant augmente la sélectivité de production d'hydrogène dans la déshydrogénation de l'hydroquinone en quinone et en hydrogène. Le solvant organique polaire fonctionne également pour dissoudre une partie considérable des autres constituants du flux d'alimentation gazeux, qui sont séparés et récupérés en tant que produits isolés.
PCT/US1996/015314 1995-11-14 1996-09-25 Procede de traitement de gaz WO1997018028A1 (fr)

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CA002230849A CA2230849A1 (fr) 1995-11-14 1996-09-25 Procede de traitement de gaz
AU71176/96A AU7117696A (en) 1995-11-14 1996-09-25 Gas treating process

Applications Claiming Priority (2)

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US55788895A 1995-11-14 1995-11-14
US08/557,888 1995-11-14

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999024531A1 (fr) * 1997-11-12 1999-05-20 Apollo Environmental Systems Corp. Procede d'elimination de sulfure d'hydrogene
US7662215B2 (en) 2004-07-12 2010-02-16 Exxonmobil Upstream Research Company Methods for removing sulfur-containing compounds

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4356161A (en) * 1981-08-24 1982-10-26 Shell Oil Company Process for reducing the total sulfur content of a high CO2 -content feed gas
US4592905A (en) * 1985-01-14 1986-06-03 Marathon Oil Company Conversion of hydrogen sulfide to sulfur and hydrogen
US5334363A (en) * 1992-12-01 1994-08-02 Marathon Oil Company Process for recovering sulfur and hydrogen from hydrogen sulfide

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4356161A (en) * 1981-08-24 1982-10-26 Shell Oil Company Process for reducing the total sulfur content of a high CO2 -content feed gas
US4592905A (en) * 1985-01-14 1986-06-03 Marathon Oil Company Conversion of hydrogen sulfide to sulfur and hydrogen
US5334363A (en) * 1992-12-01 1994-08-02 Marathon Oil Company Process for recovering sulfur and hydrogen from hydrogen sulfide

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999024531A1 (fr) * 1997-11-12 1999-05-20 Apollo Environmental Systems Corp. Procede d'elimination de sulfure d'hydrogene
US6551570B1 (en) * 1997-11-12 2003-04-22 Apollo Evironmental Systems Corp. Hydrogen sulfide removal process
US7662215B2 (en) 2004-07-12 2010-02-16 Exxonmobil Upstream Research Company Methods for removing sulfur-containing compounds

Also Published As

Publication number Publication date
CA2230849A1 (fr) 1997-05-22
AU7117696A (en) 1997-06-05

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