GB2180848A - Removing hydrogen sulphide from a gaseous mixture - Google Patents
Removing hydrogen sulphide from a gaseous mixture Download PDFInfo
- Publication number
- GB2180848A GB2180848A GB08523607A GB8523607A GB2180848A GB 2180848 A GB2180848 A GB 2180848A GB 08523607 A GB08523607 A GB 08523607A GB 8523607 A GB8523607 A GB 8523607A GB 2180848 A GB2180848 A GB 2180848A
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- GB
- United Kingdom
- Prior art keywords
- hydrogen sulphide
- regeneration gas
- adsorber
- gas
- gaseous mixture
- Prior art date
- Legal status (The legal status 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 status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
- C10K1/00—Purifying combustible gases containing carbon monoxide
- C10K1/20—Purifying combustible gases containing carbon monoxide by treating with solids; Regenerating spent purifying masses
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
- C10K1/00—Purifying combustible gases containing carbon monoxide
- C10K1/34—Purifying combustible gases containing carbon monoxide by catalytic conversion of impurities to more readily removable materials
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Separation Of Gases By Adsorption (AREA)
Abstract
A gaseous mixture (e.g. natural gas, synthesis gas, fuel gas) including hydrogen sulphide is contacted with regeneratable adsorption material 2 adsorbing hydrogen sulphide, which is subsequently regenerated by contacting said adsorption material with regeneration gas, which regeneration gas is contacted at elevated temperature with chemisorption material 4 adsorbing hydrogen sulphide. The regeneration gas may be treated with catalyst at 26 to hydrolyse any carbon oxysulphide. <IMAGE>
Description
SPECIFICATION
Removing hydrogen sulphide from a gaseous mixture
The present invention relates to removing hydrogen sulphide from a gaseous mixture including hydrogen sulphide, such as natural gas, associated natural gas, synthesis gas, or refinery fuel gas.
It is known to contact the gaseous mixture with regeneratable adsorption material adsorbing hydrogen sulphide, and subsequently to regenerate the regeneratable adsorption material with regeneration gas at elevated temperature. In the known process, regeneration gas loaded with hydrogen sulphide is first cooled to ambient temperature and subsequently contacted with liquid adsorbent to remove hydrogen sulphide from the regeneration gas. The liquid adsorbent is thereafter regenerated, and a regeneration off-gas is obtained wherein a major part of the hydrogen sulphide initially present in the gaseous mixture is concentrated.
In general the regeneration off-gas is passed to a Claus plant where hydrogen sulphide is converted to sulphur.
The known process requires large facilities to remove hydrogen sulphide from the regeneration gas, and for this reason the known process is economically unattractive for removing hydrogen sulphide from gaseous mixture, in particular if the gaseous mixture contains only a small amount of hydrogen sulphide, and if the concentration of hydrogen sulphide in the regeneration gas varies widely.
It is an object of the present invention to provide an economically attractive process.
To this end the process of removing hydrogen sulphide from a gaseous mixture including hydrogen sulphide according to the invention comprises the steps of (a) contacting in a first adsorber the gaseous mixture with regeneratable adsorption material
adsorbing hydrogen sulphide and allowing gas substantially free of hydrogen sulphide to
leave the first adsorber; (b) interrupting contacting the gaseous mixture with the regeneratable adsorption material; (c) contacting the regeneratable adsorption material with regeneration gas at elevated tempera
ture so as to desorb hydrogen sulphide therefrom and allowing regeneration gas loaded with
hydrogen sulphide to leave the first adsorber; (d) contacting in a second adsorber the regeneration gas loaded with hydrogen sulphide at
elevated temperature with chemisorption material adsorbing hydrogen sulphide; and (e) interrupting contacting the regeneratable adsorption material with the regeneration gas.
An advantage of the process according to the invention is that if the regeneration gas contains carbon dioxide, the carbon dioxide will not be adsorbed by the chemisorption material. Whereas in the known process carbon dioxide will as well be absorbed by the liquid absorbent, and will consequently be present in the regeneration off-gas which is passed to the Ciaus plant where carbon dioxide can adversily affect the operation of the Clause plant.
If carbon dioxide is present in the regeneration gas, at least part thereof can react with at least part of the hydrogen sulphide desorbed from the regeneratable adsorption material to form carbon oxysulphide which will not be adsorbed by the chemisorption material. To allow removal of the carbon oxysulphide, the regeneration gas in step (d) of the process according to the invention is first contacted with a catalyst to hydrolyze any carbon oxysulphide present in the regeneration gas.
It is observed that it is known to contact the gaseous mixture including hydrogen sulphide with chemisorption material at elevated temperature to desorb hydrogen sulphide from the gaseous mixture. The known process, however, requires heating the total volume of the gaseous mixture to the temperature required for adsorbing hydrogen sulphide on the chemisorption material.
In the process according to the invention, however, only the regeneration gas, which is a small amount in comparison with the amount of gaseous mixture, is to be heated to the temperature required for adsorbing hydrogen sulphide on the chemisorption material.
The invention will now be described in more detail by way of example with reference to the drawing wherein,
Figure 1 shows an apparatus for carrying out the process of removing hydrogensulphide from a gaseous mixture according to the invention; and
Figure 2 shows the apparatus as shown in Fig. 1 with an additional reactor.
The apparatus shown in Fig. 1 comprises a first adsorber 1 wherein regeneratable adsorption material 2 is arranged, and a second adsorber 3 wherein chemisorption material 4 is arranged.
The second adsorber 3 is connected to the first adsorber 1 by means of a connecting conduit 5 provided with a valve 6.
Connected to the first adsorber 1 are a feed gas supply conduit 8 provided with a valve 9, a purified gas discharge conduit 10 provided with a valve 11, and a regeneration gas supply conduit 15 provided with a valve 16.
The second adsorber 3 is provided with a purified regeneration gas discharge conduit 19.
To allow heating of the regeneration gas, the regeneration gas supply conduit 15 is provided with a first heater 22, and the connecting conduit 5 is provided with a second heater 23.
For the sake of clarity, control means for the valves 6, 9, 11 and 16, means for supplying fuel and oxygen to the heaters 22 and 23, and means for determining gas temperatures and gas compositions have not been shown.
During normal operation, at first valves 16 and 6 are closed and valves 9 and 11 are opened, and a gaseous mixture including hydrogen sulphide is supplied to the first adsorber 1 through the feed gas supply conduit 8. In the first adsorber 1 the gaseous mixture is contacted with the regeneratable adsorption material 2 adsorbing hydrogen sulphide, the gas substantially free of hydrogen sulphide leaves the first adsorber 1 through the purified gas discharge conduit 10.
Contacting the gaseous mixture with the regeneratable adsorbing material 2 is continued until the hydrogen sulphide content of the gas passing through the purified gas discharge conduit 10 has increased to a predetermined level. Then contacting is interrupted by closing valve 9. In addition, valve 11 is closed as well.
In order to regenerate the regeneratable adsorbing material 2 valves 16 and 6 are opened and regeneration gas is supplied to the first adsorber 1 through the regeneration gas supply conduit 15. Regeneration gas loaded with hydrogen sulphide is passed through the connecting conduit 5 into the second adsorber 3, in which the regeneration gas is contacted with chemisorption material 4 adsorbing hydrogen sulphide, and regeneration gas substantially free of hydrogen sulphide leaves the second adsorber through the purified regeneration gas discharge conduit 19.
The concentration of hydrogen sulphide in the regeneration gas increases to a maximum value and then it decreases as more hydrogen sulphide is desorbed from the regeneratable adsorption material 2.
If the temperature of the regeneration gas supplied to the first adsorber is too low to allow desorption of hydrogen sulphide from the regeneratable adsorption material 2, the regeneration gas is heated by the first heater 22.
If the temperature of the regeneration gas loaded with hydrogen sulphide leaving the first adsorber 1 is too low to allow adsorption of hydrogen sulphide on the chemisorption material, the regeneration gas passing through the connecting conduit 5 is heated by the second heater 23, which second heater 23 is switched on when the temperature of the regeneration gas leaving the first adsorber 1 reaches the required level.
When a sufficient amount of hydrogen sulphide has been desorbed from the regeneratable adsorption material 2, contacting the regeneratable adsorption material 2 with regeneration gas is interrupted by closing valve 16. In addition, valve 6 is closed as well.
Subsequently a new cycle can start, wherein at first a gaseous mixture including hydrogen sulphide is contacted with the regeneratable adsorption material 2 and wherein thereafter the regeneratable adsorption material 2 is regenerated, as described above.
In the process described with reference to Fig. 1, the regeneration gas did not contain carbon dioxide. If, however, the regeneration gas contains carbon dioxide, at least part of the carbon dioxide can react with at least a part of the hydrogen sulphide to carbon oxysulphide and water.
The carbon oxysulphide so formed cannot be adsorbed on the chemisorption material and has to be hydrolized to hydrogen sulphide. To this end the apparatus further comprises a reactor 25 (see Fig. 2) wherein material catalyzing the hydrolysis of carbon oxysulphide 26 is arranged. The inlet of the reactor 25 is connected to the connecting conduit 5, and the outlet thereof is connected to the second adsorber 3 by means of a second connecting conduit 27. Furthermore there is provided a water supply conduit 30 provided with a valve 31 connected to the connecting conduit 5.
During normal operation, at first valves 16, 6 and 31 are closed and valves 9 and 11 are opened, and a gaseous mixture including hydrogen sulphide is supplied to the first adsorber 1 through the feed gas supply conduit 8. In the first adsorber 1 the gaseous mixture is contacted with the regeneratable adsorption material 2, and gas substantially free of hydrogen sulphide leaves the first adsorber 1 through the purified gas discharge conduit 10.
Contacting is interrupted by closing valve 9 when the hydrogen sulphide content of the gas passing through the purified gas discharge conduit 10 has increased to a predetermined level. In addition, valve 11 is closed as well.
To regenerate the regeneratable adsorbing material 2, valves 16 and 6 are opened and regeneration gas, if required, heated by heater 22 is passed though the first adsorber 1 in a direction opposite to the direction wherein the gaseous mixture is passed therethrough to desorb hydrogen sulphide from the regeneratable adsorption material 2. A part of the desorbed hydrogen sulphide reacts with a part of the carbon dioxide present in the regeneration gas to form carbon oxysulphide. The concentrations of hydrogen sulphide and carbon oxysulphide in the regeneration gas leaving the first adsorber 1 increase until they reach a maximum value and then they decrease as more hydrogen sulphide is desorbed from the regeneratable adsorption material 2.
Regeneration gas loaded with hydrogen sulphide and carbon oxysulphide leaves the first adsorber 1, passes through the connecting conduit 5, is heated, if required, by the heater 23, and is introduced into the reactor 25. In the reactor 25 the regeneration gas is contacted with the material catalysing the hydrolysis of carbon oxysulphide 26, and the carbon oxysulphide is converted to hydrogen sulphide. Regeneration gas loaded with hydrogen sulphide leaving the reactor 25 is passed through the second connecting conduit 27 into the second adsorber 3 where the regeneration gas is contacted with the chemisorption material 4 adsorbing hydrogen sulphide, and regeneration gas substantially free of hydrogen sulphide leaves the second adsorber 3 through the purified regeneration gas discharge conduit 19.
When a sufficient amount of hydrogen sulphide has been desorbed from the regeneratable adsorption material 2, contacting the regeneratable adsorption material 2 with regeneration gas is interrupted by closing valve 16. In addition, valve 6 is closed as well.
Subsequently a new cycle of adsorption and regeneration can start.
When in the first adsorber 1 carbon oxysulphide is formed from carbon dioxide and hydrogen sulphide, water is formed as well. At least part of this water will be adsorbed on the regeneratable adsorption material 2 in the first adsorber 1. Therefore the regeneration gas leaving the first adsorber 1 may contain an insufficient amount of water to allow a complete conversion of carbon oxysulphide to hydrogen sulphide. To enable a complete conversion of carbon oxysulphide additional water is supplied to the regeneration gas through water supply conduit 30 by opening valve 31. The supply of additional water is stopped when the amount of water in the regeneration gas is sufficient to allow a complete conversion of carbon oxysulphide.
In the processes described with reference to Figs. 1 and 2 the gaseous mixture flowed upwardly though the first adsorber 1, and the regeneration gas downwardly. The flows of these gases, however, can be reversed so that the gaseous mixture flows downwardly and the regeneration gas upwardly. In addition, regeneration gas can as well be passed downwardly through the second adsorber, or upwardly through the reactor.
The regeneratable adsorption material in the first adsorber will suitably be a molecular sieve, such as a zeolite, or an alkali metal- or an alkaline earth metal-aluminium silicate, having a pore diameter between 3x 10 10 m and 10x 10 'Om. In general, the gaseous mixture has less than
100 ppmv hydrogen sulphide, and it will be supplied to the first adsorber at a temperature up to about 80 C and most likely between O"C and 35"C, and at a pressure between 5 MPa and 11
MPa. Suitably the diameter of the first adsorber is such that the average gas velocity in the first adsorber is between 0.02 m/s and 0.3 m/s. Adsorption will last until saturation has been reached, as an example adsorption takes about 8 hours.
During contacting the regeneratable material with regeneration gas to desorb hydrogen sulphide therefrom, the temperature of the regeneration gas will be between 200"C and 450 C, and the pressure of the regeneration gas will be between 5 MPa and 10 MPa. The average gas velocity of the regeneration gas applied in the first adsorber will be between 0.003 m/s and 0.07 m/s.
The regeneration gas is supplied to the first adsorber until a sufficient amount of hydrogen sulphide has been removed, as an example regeneration takes about 3 hours. The volume of regeneration gas supplied per unit of time is about 5% to 15% of the volume of gaseous mixture supplied per unit of time to the first adsorber.
Hydrogen sulphide is removed from the regeneration gas in the second adsorber, wherein the hydrogen sulphide is adsorbed by chemisorption material. Suitable chemisorption material is for example zinc oxide, iron (III) oxide, zinc ferrite, or mixtures thereof, or supported molten salts of a mixture of lithium carbonate and potasium carbonate on aluminium oxide.
During removing of hydrogen sulphide from the regeneration gas in the second adsorber, temperature of the regeneration gas will be between 200"C and 450"C. The diameter of the second adsorber will be such that the average gas velocity is between 0.02 m/s and 0.5 m/s.
The volume of chemisorption material will be such that it takes about 1 to 12 months before the chemisorption material has to be replaced because it is fully loaded with hydrogen sulphide.
In stead of replacing the chemisorption material, it can be treated, while remaining in the second adsorber, so as to desorb hydrogen sulphide therefrom.
Suitable material catalyzing the hydrolysis of carbon oxysulphide comprises for example potasium on aluminium oxide or titanium on silicon oxide. In general the temperature for hydrolyzing carbon oxysulphide will be between 125"C and 300"C, and the volume of said material will be such that the gas hourly space velocity is between 500 and 3000 Sm3 gas per m3 material per
hour, wherein 1 Sm3 gas equals 1 m3 gas at a temperature of 0 C and at a pressure of 0. 1
MPa.
In the apparatus as shown Fig. 1 and 2, there was only one first adsorber. In a suitabie embodiment of the invention the apparatus comprises two first adsorbers, wherein during normal operation one of the two first adsorbers is adsorbing hydrogen sulphide from the gaseous mixture passing therethrough and the other is being regenerated. To enable continuous operation the apparatus can comprise even three or four first adsorbers.
In the apparatus as shown in Fig. 2 the material catalysing the hydrolysis of carbon oxysul phide is arranged in a separate reactor. This material can also be arranged in the second adsorber, upstream of the chemisorption material.
The regeneration gas can be nitrogen. A suitable regeneration gas is the gas substantially free of hydrogen sulphide leaving the first adsorber, in which case regeneration gas substantially free of hydrogen sulphide leaving the second adsorber can be supplied to the purified gas discharge conduit.
Claims (5)
1. Process of removing hydrogen sulphide from a gaseous mixture including hydrogen sulphide comprising the steps of (a) contacting in a first adsorber the gaseous mixture with regeneratable adsorption material
adsorbing hydrogen sulphide, and allowing gas substantially free of hydrogen sulphide to
leave the first adsorber; (b) interrupting contacting the gaseous mixture with the regeneratable adsorption material; (c) contacting the regeneratable adsorption material with regeneration gas at elevated tempera
ture so as to desorb hydrogen sulphide therefrom and allowing regeneration gas loaded with
hydrogen sulphide to leave the first adsorber; (d) contacting in a second adsorber the regeneration gas loaded with hydrogen sulphide at
elevated temperature with chemisportion material adsorbing hydrogen sulphide; and (e) interrupting contacting the regeneratable adsorption material with the regeneration gas.
2. Process as claimed in claim, wherein in step (d) the regeneration gas is first contacted with a catalyst to hydrolyze any carbon oxysulphide present in the regeneration gas.
3. Process as claimed in claim 1 or 2, wherein the temperature of the regeneration gas contacting the regeneratable adsorption material in the first adsorber so as to desorb hydrogen sulphide therefrom is between 200"C and 450"C.
4. Process as claimed in any one of the claims 1-3, wherein the temperature of the regeneration gas contacting the chemisorption material in the second adsorber to adsorb hydrogen sulphide is between 200"C and 450"C.
5. Process of removing hydrogen sulphide from a gaseous mixture including hydrogen sulphide substantially as described with reference to the Figures.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB08523607A GB2180848A (en) | 1985-09-25 | 1985-09-25 | Removing hydrogen sulphide from a gaseous mixture |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB08523607A GB2180848A (en) | 1985-09-25 | 1985-09-25 | Removing hydrogen sulphide from a gaseous mixture |
Publications (2)
Publication Number | Publication Date |
---|---|
GB8523607D0 GB8523607D0 (en) | 1985-10-30 |
GB2180848A true GB2180848A (en) | 1987-04-08 |
Family
ID=10585679
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB08523607A Withdrawn GB2180848A (en) | 1985-09-25 | 1985-09-25 | Removing hydrogen sulphide from a gaseous mixture |
Country Status (1)
Country | Link |
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GB (1) | GB2180848A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4830733A (en) * | 1987-10-05 | 1989-05-16 | Uop | Integrated process for the removal of sulfur compounds from fluid streams |
US4865826A (en) * | 1986-01-10 | 1989-09-12 | Imperial Chemical Industries Plc | Desulphurization |
US5114689A (en) * | 1987-10-05 | 1992-05-19 | Uop | Integrated process for the removal of sulfur compounds from fluid streams |
EP0661374A1 (en) * | 1993-12-30 | 1995-07-05 | Shell Internationale Researchmaatschappij B.V. | Process for removing nitrogen compounds from synthesis gas |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1246483A (en) * | 1967-06-20 | 1971-09-15 | Messer Griesham G M B H | Process and device for the removal of homogeneously dissolved impurities from gases and liquids |
US3712027A (en) * | 1971-01-22 | 1973-01-23 | Continental Oil Co | Vapor adsorption process for recovering selected components from a multi-component gas stream |
EP0056197A1 (en) * | 1981-01-02 | 1982-07-21 | Exxon Research And Engineering Company | Process for removal of sulfur from moisture-bearing, sulfur-containing hydrocarbon process streams |
-
1985
- 1985-09-25 GB GB08523607A patent/GB2180848A/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1246483A (en) * | 1967-06-20 | 1971-09-15 | Messer Griesham G M B H | Process and device for the removal of homogeneously dissolved impurities from gases and liquids |
US3712027A (en) * | 1971-01-22 | 1973-01-23 | Continental Oil Co | Vapor adsorption process for recovering selected components from a multi-component gas stream |
EP0056197A1 (en) * | 1981-01-02 | 1982-07-21 | Exxon Research And Engineering Company | Process for removal of sulfur from moisture-bearing, sulfur-containing hydrocarbon process streams |
Non-Patent Citations (1)
Title |
---|
WO A1 82/02499 * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4865826A (en) * | 1986-01-10 | 1989-09-12 | Imperial Chemical Industries Plc | Desulphurization |
US4830733A (en) * | 1987-10-05 | 1989-05-16 | Uop | Integrated process for the removal of sulfur compounds from fluid streams |
US5114689A (en) * | 1987-10-05 | 1992-05-19 | Uop | Integrated process for the removal of sulfur compounds from fluid streams |
EP0661374A1 (en) * | 1993-12-30 | 1995-07-05 | Shell Internationale Researchmaatschappij B.V. | Process for removing nitrogen compounds from synthesis gas |
EP0661375A1 (en) * | 1993-12-30 | 1995-07-05 | Shell Internationale Researchmaatschappij B.V. | Process for removing nitrogen compounds from synthesis gas |
Also Published As
Publication number | Publication date |
---|---|
GB8523607D0 (en) | 1985-10-30 |
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Legal Events
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WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |