AU746323B2

AU746323B2 - Process for deacidizing a gas with a very high acid gas content

Info

Publication number: AU746323B2
Application number: AU92436/98A
Authority: AU
Inventors: Etienne Lebas
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 1997-11-19
Filing date: 1998-11-17
Publication date: 2002-04-18
Anticipated expiration: 2018-11-17
Also published as: GB9825073D0; DK199801514A; GB2331526A; NO985367L; FR2771022B1; AU746323C; AU9243698A; CA2252041A1; NZ332835A; NO318532B1; GB2331526B; NO985367D0; FR2771022A1

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): INSTITUT FRANQAIS DU PtTROLE Invention Title: PROCESS FOR DEACIDIZING A GAS WITH A VERY HIGH ACID GAS CONTENT The following statement is a full description of this invention, including the best method of performing it known to me/us: FIELD OF THE INVENTION The object of the present invention is to process a gas containing at least one hydrocarbon and at least one acid gas in high concentration in order to free it at least partly from the acid gas contained therein.

The process according to the invention is particularly well-suited for deacidizing of a natural gas.

BACKGROUND OF THE INVENTION 0 French patents FR-2,605,241 and FR-2,636,857 describe treating processes using a refrigerated physical solvent allowing the various stages of a gas processing, including deacidizing and water removal, to be carried out.

0 0 These processes have the advantage, in relation to prior techniques, notably of offering the possibility of using the same polar solvent for dehydration and deacidizing of the gas, and the possibility of regenerating the solvent by direct contact, in an absorption column or contactor, between the solvent and the gas to 15 be processed (patent FR-2,605,241), leading to considerable power consumption, investment and facility size gains.

However, for gases containing a very high acid gas concentration, implementing such processes presents drawbacks. The gas to be processed must be cooled prior to being passed into the acid gas absorption column. This cooling stage leads to the condensation of a very large amount of hydrocarbons and of acid gases. This liquid phase must be stabilized, which leads to the production of i stabilization gas in large amounts that must then be recompressed and recycled.

The presence of this recompression stage harms this type of process because it implies high investment and operating costs.

SUMMARY OF THE INVENTION The present invention overcomes the drawbacks of the prior art by proposing a different approach using an absorption column working with a thermal gradient.

The gas to be processed is for example fed, without any prior refrigeration stage, •into the column where a cold polar physical solvent countercurrent circulates.

S. @0 0***Absorption of the acid gases in the column advantageously prevents 10t condensation of these acid gases in a liquid hydrocarbon phase. In fact, the hydrocarbon dew point of the gas at absorption pressure decreases greatly when the acid gas content decreases.

Figure 1 shows, in a temperature pressure diagram, two envelope S* curves A and B corresponding to the gas to be processed and to the processed *:see* gas, and the corresponding dew points bearing reference letters a and b.

Line C represents the thermal profile AT existing in the absorption column, point a' corresponding to the operating conditions of the first stage, and b' of the upper stage.

Figure 1 allows to be aware of the extent of the thermal profile of the absorption column for a given calculation example. The evolution of the envelope curve of the gas in this column allows to prevent formation of a liquid 3 hydrocarbon phase; whatever the stage considered, the temperature is such that the gas is very far from the hydrocarbon dew point thereof.

In the description hereafter, the expression "contact zone" or the expression "contactor" are used indiscriminately to refer to the part of the device where a fluid to be processed is contacted with a solvent selective towards acid gases.

Similarly, the expression "rich solvent phase" corresponds to a solvent phase enriched in acid gas and "poor solvent phase" to a solvent phase depleted in acid gas during the process.

According to the present invention there is provided a process for treating a gas containing at least one acid gas and at least one hydrocarbon, in order to remove at least partly the acid gas or gases from the o: process gas including the steps of: S- contacting by counter-current said gas to be 20 processed with a physical solvent selective towards said "acid gases in a contactor, and simultaneously, S- producing in said contactor a temperature gradient in order to prevent condensation of a liquid hydrocarbon phase and to obtain a processed gas depleted 25 in acid gases and a solvent phase enriched in acid gases, said gas to be processed being introduced into said o: contactor at an initial temperature Tg ranging between 10 0 C and 50°C and said physical solvent being introduced in said contactor at an initial temperature Tm ranging between -50°C and 0°C.

The solvent is for example a physical polar solvent.

\\Melb_files\home$\Gale\Keep\speci\92436.98.doc 19/02/02 The mixture of solvent and of water is for example flowed in countercurrent to the gas to be processed, the gas to be processed being introduced at an initial temperature Tg and the solvent mixture at an initial temperature Tm, the temperature values Tg and Tm being selected to generate the required gradient in the contactor, and Tg being greater than Tm.

At least a fraction of said gas to be processed can be withdrawn at a temperature level Ti, said gas fraction can be cooled by means of a heat exchange with at least a fraction of the processed gas and re-injected at a temperature level •below Ti.

*<.0S qO At least a fraction of the processed gas freed from most of the acid gases is S•used for example to refrigerate the gas to be processed by circulating said fraction countercurrent to said gas to be processed.

o° .The temperature difference between the top and the bottom of the absorption column can range, in absolute value, between 5 and 150'C, preferably between 15 30 and 100'C.

The solvent phase enriched in acid gas can be regenerated by means of a •••simple expansion.

According to another embodiment, the solvent phase enriched in acid gas is regenerated by means of a distillation process at a pressure below the absorption pressure.

5 The solvent phase enriched in acid gas can be regenerated at least partly by expanding it and by contacting it with at least a fraction of regenerated solvent phase and by producing a gas with a controlled acid gas content.

According to another embodiment, the solvent phase enriched in acid gas is at least partly regenerated by means of a distillation process with simultaneous heat exchange between said solvent phase which is progressively heated by the solvent phase resulting from said regeneration, which is cooled by circulating countercurrent to the solvent phase which is regenerated.

The water accumulated during the process in the solvent phase can be drained.

According to another aspect of the present invention there is provided a device for processing a gas containing at least one acid gas and at least one hydrocarbon including at least one first delivery line for said gas to be processed and at least one second delivery oooo line for a physical solvent capable of collecting acid gases, said first and second delivery lines and being S.connected to a contactor in order to introduce said gas to be processed at an initial temperature ranging between ee 50 0 C and 0 0 C and to introduce said physical solvent at an eoe 25 initial temperature ranging between 10*C and 50 0 C, said contactor being suited to work with a temperature gradient over at least part of the length of said contactor in order to obtain at an outlet a gas depleted in acid gases, discharged through a third line, and a solvent phase enriched in acid gases withdrawn through a fourth line.

The contactor can comprise means for withdrawing and for re-injecting the fluid and/or the gas circulating in said contactor.

\\Melbfiles\home$\Gale\Keep\speci\92436.98.doc 19/02/02 The device comprises for example a circuit allowing to drain at least part of the water accumulated in the fluid capable of collecting the acid gases.

The device and the process described above are used for processing a natural gas comprising acid gases such as CO: 2 and/or H 2

S.

BRIEF DESCRIPTION OF THE DRAWINGS

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Other features and advantages of the invention will be clear from reading the description hereafter, given by way of non limitative example, with reference to 0000 the accompanying drawings wherein Figure 1 shows the evolution of the envelope curves of a gas in a thermal gradient absorption column, 0o 0• Figure 2 diagrammatically shows the principle of the process according to the invention, ooooo Figures 3 to 5 describe embodiments comprising various solvent regeneration S stages, Figures 6 and 7 diagrammatically show examples of energy integration around the contactor, Figure 8 shows an example of a pattern allowing to remove the water accumulated in the solvent, Figure 9 diagrammatically shows an embodiment example of the process.

DETAILED DESCRIPTION OF THE INVENTION The principle of the process according to the invention is described in connection with the diagram of Figure 2, which shows an example of a device layout applied for example to the processing of a natural gas in order to deacidize it.

The natural gas to be processed, containing acid gases and at least one hydrocarbon, is fed through line 1 into absorption column or contact zone C1 where it is contacted, countercurrent for example, with a cold mixture of solvent o oo and of water flowing in through line 2, the solvent phase comprising for example @000 10 at least one polar solvent. A temperature gradient determined as a function of the phase diagram of the gas to be processed (Figure 1) is generated in contact zone 0 0 0 Cl1 so as to prevent condensation of a hydrocarbon phase containing acid gases in 0@*S this zone. In the contact zone, the acid gases are selectively absorbed in the solvent phase.

00000 0 A gas phase depleted in acid gases is discharged in the upper part of contactor o Cl, through line 3.

In the lower part of contact zone or contactor Cl1, a solvent phase containing acid gases is withdrawn through line 4.

The temperature gradient is generated for example by introducing the gas to be processed at the bottom of contactor C 1, at a temperature ranging between and 50'C, and the solvent-water mixture at the top of the contactor at a temperature ranging between 0 and -501C.

I- 11 The flow rate and the temperature of the solvent at the top of the absorption column are advantageously controlled so as to obtain a desired acid gas concentration in the processed gas andto prevent condensation of hydrocarbons in the contactor.

The solvent phase coming from contactor C1 is expanded through expansion valve V1, fed into a separation drum B1 which allows to split it into a partly regenerated solvent phase withdrawn from the bottom through a line 5 and a gas r •phase discharged through a line 6 at the top of the drum. This gas phase contains .•co-absorbed acid gases and hydrocarbons. It can possibly be used as fuel-gas or to recompressed and recycled to contactor C1.

The water content of the solvent phase can preferably be at least 10 in mass S- fraction.

0 0 o The partly regenerated solvent phase coming from drum B1 through line 5 is

S

S. 000expanded through a valve V2, then fed into a drum B2 which separates the S 15 solvent phase withdrawn from the bottom through a line 7 and the gas phase withdrawn from the top through a line 8. The solvent phase is expanded through a valve V3, then fed into a separation drum B3 which separates a solvent phase withdrawn from the bottom of the drum through a line 9 and a gas phase withdrawn from the top through a line The gas phases discharged through lines 6, 8 and 10 are rich in acid gases.

The solvent phase from drum B3 is sufficiently depleted in acid gases to be recycled to contactor C1. It may first be necessary to withdraw at least part of the solvent through a line 11 in order to prevent accumulation of water carried by the gas to be processed introduced through line 1. The rest of the solvent is then recirculated by a recycling pump P1, mixed with make-up solvent flowing in through a line 13 in order to compensate for the solvent losses, in the deacidized gas, in the acid gases produced and possibly in drain line 11 if the latter is not recycled after removal of the water it contains. The resulting mixture circulates in a line 14, it is cooled in an exchanger El by means of an auxiliairy external coolant, for example, and recycled to contact zone Cl1 through line 2.

0:0. The treating process according to the invention mainly comprises at least the S. 10 following stages *•0 contacting, in an absorption column, the gas to be processed with a fluid selective towards acid gases, for example a mixture of polar solvent and of water, and 000* generating a temperature gradient in this absorption column in order to achieve 15 absorption of the acid gases without condensation of the hydrocarbons or of the acid gases, or at least, if such a condensation occurs, the condensed liquid phase is present in minute amounts, a processed gas depleted in acid gases and a solvent phase enriched in acid gases are obtained.

The absorption and the temperature gradient can be obtained by countercurrent circulation of the gas to be processed introduced at the bottom of the contactor at a temperature Tg and of the solvent-water mixture introduced at the top of the column at a temperature Tm, with Tm Tg.

The temperature difference I Tm Tg I can range between 5 and 100°C.

The value of the pressure prevailing in the absorption column can range between 1 and 20 MPa.

Figure 3 illustrates a variant of the regeneration stage where a distillation column C2 positioned after the drum B 1 of Figure 2 is used, which allows to carry out a deeper regeneration of the solvent phase than that obtained by means of the pattern of Figure 2.

o.o• The partly regenerated solvent from drum B 1 is expanded through valve V2, then heated in an exchanger E2 prior to being fed, through a line 20 for example, into the central part of distillation column C2.

The acid gases produced by distillation are discharged at the top of column C2 through a line 21, cooled in an exchanger E3 and fed into a decantation or 0 see separation drum D1. At the outlet of this decantation drum, a fraction of the acid gases is discharged through a line 23 and the liquid phase comprising the condensed solvent phase is sent back through a line 22 to distillation column C2 to be used as a reflux.

The regenerated solvent phase is withdrawn from the bottom of distillation column C2 through a line 24, cooled in an exchanger E2 prior to being sent through a line 25 to drain line 11 and recycling pump P1 according to the pattern described in connection with Figure 2.

Figure 4 illustrates an embodiment variant of the device of Figure 3 where separation drum B 1 is equipped with a contact zone whose purpose is to control an acid gas specification on the gaseous flow withdrawn through line 6.

To that effect, a fraction of the solvent phase regenerated and recycled according to the pattern of Figure 3 is withdrawn and sent through a line 26 situated at the top of contact zone 27 of drum B 1.

00 0 *000 oIn this contact zone 27, part of the acid gases is absorbed by means of a o•determined amount of solvent so as to obtain, through line 6, a gaseous effluent having a controlled acid gas content selected as a function of a desired 10 specification.

Figure 5 illustrates another solvent regeneration mode. Exchanger E2 of Figure 3 is replaced by a stripper exchanger ES1 which performs a distillation 0with simultaneous heat exchange between the rich solvent phase introduced through line 7 at the level of the upper part of stripper exchanger ES 1, which is progressively heated, and the solvent phase resulting from the regeneration stage, sent to the lower part through line 24 coming from distillation column C2 and which is cooled by circulating countercurrent to the solvent phase which is regenerated.

At the outlet of stripper exchanger ES 1, a rich solvent phase is obtained at the bottom and sent through line 20 to distillation column C2, a rich gas is obtained at the top and discharged through line 28, and in the upper part of the column, the regenerated solvent phase is withdrawn through a line 29 connected to recycling pump P1.

The internal heat exchange described above between the solvent phase rich in acid gases and the solvent phase depleted in acid gases can be performed by means of various devices.

Integrated exchanger ES 1 can be a shell-and-tube type exchanger. In this case, the regenerated solvent phase withdrawn from the base of column C2 circulates in the tubes, distillation is performed outside the tubes and inside the shell.

Stripper exchanger ES1 can be a plate exchanger, the tubes being placed above each plate so as to be immersed in the rich solvent phase to be collected oooo S. and circulating on each plate.

Stripper exchanger ES1 can be a continuous-contact exchanger, the rich solvent phase then trickling on the tubes.

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The regenerated solvent phase withdrawn from the base of column C2 can 5 also circulate outside the tubes and inside the shell. Distillation is then performed inside the tubes, which are preferably vertical and provided with an inner S 15 packing.

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A vertical plate exchanger can also be used for the absorption columns and/or the stripper exchanger described in the previous figures. The spaces between the various plates are alternately occupied by the regenerated solvent phase withdrawn from the base of column C2 and by the solvent phase, as well as by the generated vapour phase circulating countercurrent in the column during the distillation process. It is, for example, a brazed aluminium type or a stainless steel I I; 11 type exchanger, the plates being either butt welded or metal diffusion welded over the total surface of contact between the plates.

Figure 6 shows an embodiment example of the absorption stage where the cold processed gas is used to cool at least partly the gas to be processed s circulating in the absorption column. The gas is withdrawn, during processing, at the level of a plate of column C1 or between two packing zones of column C1 through a line 30, cooled in an exchanger E4 by the processed gas discharged through line 3, then re-introduced into column C2 through a line 31. The 6. withdrawal and injection levels, as well as the number thereof, are determined .i 10 along the column in order to optimize frigorie recovery on the processed gas 6000 collected in line 3.

Figure 7 shows another embodiment variant of the absorption stage where C "•simultaneous heat exchange is performed between the processed gas that is progressively heated and the gas to be processed in contact with the solvent, 15 which is cooled by countercurrent circulation. This type of thermal exchange can be achieved by means of various devices which have been described above in connection with Figure The processed gas coming from absorption column C1 through line 3 is sent back through this line to the top of the column in which it circulates countercurrent to the gas introduced at the bottom of the column through line 1.

After exchanging its frigories with the gas to be processed, it flows out heated through a line 33 at the bottom of the column for example.

1: As the gas to be processed can contain water in various forms, in some cases it may be necessary to remove this water in order to prevent the accumulation thereof in the solvent phase.

Figure 8 shows a draining pattern allowing to remove the water accumulated in the solvent phase during processing and comprising a contactor C3 situated downstream from thermal-gradient contactor C1.

The crude gas to be purified is split into two fractions flowing respectively 0~e 0:,o through lines 35 and 36.

0000 A first fraction passes through line 36 which joins line 1 (Figure 1) delivering the gas into contactor C1.

The second fraction of gas to be processed is sent through line 35 to the lower part of contactor C3. o••o• oo oo The water-laden solvent phase from drain line 11 (Figure 1) is sent to the top of contactor C3 by means of a pump P2 and of a line 34.

000.00 At the outlet of contactor C3, a solvent-laden gas is recovered and discharged at the top through a line 38 which communicates with delivery line 1, and a practically solvent-free aqueous phase is recovered and discharged at the bottom of the contactor through a line 37.

The present invention will be clear from reading the description below of a non limitative gas processing example.

This example, described in connection with Figure 9, allows to deacidize a natural gas with a very high C02 content.

The natural gas to be processed has for example the following composition in by moles NITROGEN 1.20 CARBON DIOXIDE 70.50 HYDROGEN SULFIDE 0.21 METHANE 27.64 ETHANE 0.24 PROPANE 0.10 ISOBUTANE 0.02 BUTANE 0.02 ISOPENTANE 0.01 PENTANE 0.01 HEXANE 0.03 This gas is saturated with water at a temperature of 30'C and at a pressure of 7 MPa. Its molar flow rate is 22,400 kmol/h. This gas is split into two fractions in lines 35 and 36. The gas in line 35 is sent to contactor C3 at a molar flow rate of 17,000 kmol/h. A fraction of solvent containing about 6 kmon of water and 54 2o kmon of methanol is injected countercurrent thereto through line 34. At the bottom of contactor C3, a flow of 17 kmol/h of water containing about 200 molar ppm of methanol is withdrawn through line 37.

The methanol-laden gas coming from the top of contactor C3 is mixed with the gas of line 36, then with the recycled gas coming from regeneration drum B I 0 0 0 a 00 S S 5.5

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0@ Sr 0 r through a line 40. It is then sent to contactor C1. At the top of contactor C1, a solvent containing about 5,500 kmol/h of water and 49,500 kmol/h of methanol is injected through line 2 at a temperature of -30 0 C. Under such conditions, contactor 1 is operated with a thermal gradient of 23 0 C at the bottom to -23 0 C at the top. The processed gas is withdrawn from the top of contactor C1 through line 3. It has a flow rate of 6,603 kmol/h and contains about 87 by moles of methane and 8 by moles of CO 2 This gas is heated in exchanger E to a temperature of 50°C prior to being discharged through a line 41.

The rich solvent is withdrawn from contactor Cl through line 4. It is 10 expanded to a pressure of 3.5 MPa through valve Vl. At the outlet of separation drum B1, a solvent phase is withdrawn through line 5 and a gas phase is discharged through line 6. The gas phase containing about 6,800 kmol/h of CO 2 and 1,300 kmol/h of methane is compressed to 7 MPa by a compressor K, then cooled to 30°C by an exchanger E in order to be recycled to the base of contactor C1 through line The solvent from line 5 is expanded to a pressure of 1 MPa through valve V2, split in drum B2 into a gas phase withdrawn through line 8 and a solvent phase withdrawn through line 7. The gas from line 8 has a flow rate of 10,153 kmol/h and a concentration of 95 by moles of CO 2 The solvent is again expanded to a pressure of 0.2 MPa through valve V3, split in drum B3 into a gas phase withdrawn through line 10 and a solvent phase withdrawn through line 9. The gas in line 10 has a flow rate of 5,666 kmol/h and a concentration of 98.5 by moles of CO 2 A fraction of the solvent is withdrawn through drain line 11, sent to pump P2 in order to be injected into contactor C3 through line 34. The other solvent fraction is sent to pump P1, cooled in exchanger El to -30'C prior to being fed into contactor C 1 through line 2.

The process allows to remove the acid gases contained in a natural gas, as well as those included in a refinery gas or in any gaseous effluent simultaneously containing hydrocarbons and acid gases. It allows to remove acid gases such as

H

2 S and C0 2 and also mercaptans of chemical formula R-SH, COS and CS 2 The various stages of the process according to the invention can be carried out 10 in columns provided with contact zones allowing mass transfer between the gas phases and the liquid phases. These contact zones are therefore equipped with 1.969 perforated trays, bubble-cap trays, valve trays, or they may be continuous contact a 0* zones containing a packing. This packing can consist of bulk elements such as, fs: for example, Raschig rings, Pall rings, Berl saddles or any other packing known 15 to the man skilled in the art. It may also consist of stacked packings made of gauze, knitted fabric, or of sheets that can be perforated or corrugated and/or :0.

90forming channels allowing efficiency to be increased.

oooooo These trays or these packings can be made from various materials such as ceramic, aluminium, stainless steel, plastic.

The fluid selective towards acid gases can comprise a polar solvent selected from methanol, an alcohol, an ether, a polyethylene glycol ether, propylene carbonate.

18 It is also possible, without departing from the scope of the invention, to use a solvent made up of two polar solvents, or a polar solvent and an amine.

In the clams which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents forms part of the common general knowledge in the art, in Australia or in any other country.

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Claims

1. A process for treating a gas containing at least one acid gas and at least one hydrocarbon, in order to remove at least partly the acid gas or gases from the process gas including the steps of: contacting by counter-current said gas to be processed with a physical solvent selective towards said acid gases in a contactor, and simultaneously, producing in said contactor a temperature gradient in order to prevent condensation of a liquid hydrocarbon phase and to obtain a processed gas depleted in acid gases and a solvent phase enriched in acid gases, said gas to be processed being introduced into said contactor at an initial temperature Tg ranging between 10°C and 50°C and said physical solvent being introduced in said contactor at an initial temperature Tm ranging between -50°C and 0°C. S: 20

2. A process as claimed in claim 1, in which at least a fraction of said gas to be processed is withdrawn S" *at a temperature level Ti, said withdrawn gas fraction being cooled by means of heat exchange with at least a *fraction of the processed gas and being re-injected at a 25 temperature less than Ti.

3. A process as claimed in claim 2, in which at least a fraction of the processed gas that is substantially free of most of the acid gases is used to cool the gas to be processed by circulating said withdrawn fraction of processed gas countercurrent to said gas to be processed.

4. A process as claimed in any one of claims 1 to 3, in which a temperature difference ranging, in absolute value, between 30 and 100°C, is generated in the contactor.

A process as claimed in any one of claims 1 to 4, in which the solvent phase enriched in acid gases is \\Melb_files\homeS\Gale\Keep\speci\92436.98.doc 19/02/02 20 regenerated by simple expansion.

6. A process as claimed in any one of claims 1 to 4, in which the solvent phase enriched in acid gases is regenerated by a distillation process at a pressure below the absorption pressure.

7. A process as claimed in any one of claims 1 to 4, in which the solvent phase enriched in acid gases is at least partly regenerated by expanding and contacting the solvent phase enriched with acid gases with at least a fraction of regenerated solvent phase, and by producing a gas with a controlled acid gas content.

8. A process as claimed in any one of claims 1 to 4, in which the solvent phase enriched in acid gases is at least partly regenerated by a distillation process with simultaneous heat exchange between said solvent phase that is progressively heated by the solvent phase resulting from said regeneration, which is cooled by circulating countercurrent to the solvent phase that is regenerated.

9. A process as claimed in any one of the previous ooo 20 claims, in which the water accumulated during the process in the solvent phase is drained. A device for processing a gas containing at least one acid gas and at least one hydrocarbon including at least one first delivery line for said gas to be processed 25 and at least one second delivery line for a physical S.solvent capable of collecting acid gases, said first and second delivery lines being connected to a contactor in order to introduce said gas to be processed at an initial temperature ranging between 50 0 C and 0°C and to introduce said physical solvent at an initial temperature ranging between

10'C and 50°C, said contactor being suited to work with a temperature gradient over at least part of the length of said contactor in order to obtain a gas depleted in acid gases at an outlet for discharge through a third line, and a solvent phase enriched in acid gases for withdrawal through a fourth line.

11. A device as claimed in claim 10, in which said \\Melbfiles\home$\Gale\Keep\speci\92436.98.doc 19/02/02 21 contactor includes means for withdrawing and for re- injecting the fluid and/or the gas circulating in said contactor.

12. A device as claimed in claim 10 or 11 further including a circuit allowing drainage of at least part of the water accumulated in the fluid capable of collecting acid gases.

13. Use of the method as claimed in any one of claim 1 to 9 and of the device as claimed in any one of claims 10 to 12 for processing a natural gas including acid gases.

14. Use of the method of claim 13 in which the acid gases include carbondioxide and/or hydrogensulfide.

A method of using the device of any one of claims 10 to 12 in the process of any one of claims 1 to 9 for treating a natural gas to substantially remove acid gases.

16. A method according to claim 15 in which the acid gases include carbondioxide and/or hydrogensulfide.

17. A process for treating a gas containing at least 20 one acid gas and at least one hydrocarbon substantially as herein before described with reference to the accompanying drawings.

18. A device for processing a gas containing at least one acid gas and at least one hydrocarbon substantially as 25 herein before described with reference to any one of the foregoing drawings. oo: Dated this 19th day of FEBRUARY 2002 INSTITUT FRANCAIS DU PETROLE By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia \\Melb_files\homeS\Gale\Keep\speci\92436.98.doc 19/02/02