U.S. patent application number 11/366561 was filed with the patent office on 2007-01-25 for process of removal of sulphur compounds from hydrocarbon streams using adsorbents.
Invention is credited to Peter Meyer, Michel Thomas.
Application Number | 20070017852 11/366561 |
Document ID | / |
Family ID | 34941995 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070017852 |
Kind Code |
A1 |
Meyer; Peter ; et
al. |
January 25, 2007 |
Process of removal of sulphur compounds from hydrocarbon streams
using adsorbents
Abstract
The invention concerns a process for the removal of sulphur
compounds from a hydrocarbon stream, especially a gaseous
hydrocarbon gas stream, which process comprises contacting said gas
stream with an adsorbent comprising at least a zeolite having a
pore diameter of at least 5 .ANG. to adsorb the sulphur compounds
thereon, the adsorption procedure followed by a regeneration
procedure of used, loaded adsorbent by contacting the said loaded
adsorbent with a regeneration gas stream having a relative water
humidity between 1-100% for certain steps of the regeneration and a
water content of below 5 ppmV for other steps thus to replace the
adsorbed sulphur compounds by water. Suitably the regeneration is
followed by a dry regeneration treatment to finalize the
regeneration. The process of the invention allows to send the
sulphur compounds containing regeneration gas without further
treatment of e.g. physical/chemical absorption for sulphur
components concentration to an appropriate treatment for sulphur
removal such as e.g. a Claus unit.
Inventors: |
Meyer; Peter; (Paris,
FR) ; Thomas; Michel; (Lyon, FR) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET
SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
34941995 |
Appl. No.: |
11/366561 |
Filed: |
March 3, 2006 |
Current U.S.
Class: |
208/213 |
Current CPC
Class: |
B01D 2253/308 20130101;
B01D 2257/306 20130101; B01D 2256/24 20130101; B01D 2257/304
20130101; B01D 2257/80 20130101; Y02C 20/40 20200801; B01D 2257/30
20130101; B01D 53/04 20130101; B01D 2253/108 20130101; B01D
2259/40083 20130101; Y02C 10/08 20130101 |
Class at
Publication: |
208/213 |
International
Class: |
C10G 45/04 20060101
C10G045/04; C10G 25/00 20060101 C10G025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 8, 2005 |
EP |
05.290.520.5 |
Claims
1. A process for the removal of sulphur compounds from a
hydrocarbon stream, especially a gaseous hydrocarbon gas stream,
comprising said sulphur compounds, which process comprises
contacting said gas stream with at least an adsorbent comprising a
zeolite having a pore diameter of at least 5 .ANG. to adsorb the
sulphur compounds thereon and to obtain a treated gas, the
adsorption process is followed by a regeneration procedure of used,
loaded adsorbent, characterized in that the regeneration procedure
comprises the following steps: a/ contacting the said loaded
adsorbent with a first dry gas having a temperature within the
range from 15-200.degree. C. and a pressure of 5-70 bara in a
turn-around way by recycling the first dry gas at least partially
and preferably completely through the adsorbent, b/ then contacting
the loaded adsorbent with a regeneration gas stream having a
relative water humidity between 1 and 100% saturation, a
temperature of 15-200.degree. C. and a pressure of 5-70 bara being
partially recycled through the adsorbent or not, c/ and finally
contacting the said loaded adsorbent with a second dry gas having a
temperature within the range from 50-350.degree. C. and a the
pressure of 5-70 bara.
2. A process according to claim 1, in which the contacting of gas
in step a) and b) are performed in the same flow direction as the
contacting in the adsorption process.
3. A process according to claim 1, in which the hydrocarbon stream
is natural gas, associated gas, a natural gas liquids stream, a
natural gas condensate stream or a refinery gas stream.
4. A process according to claim 1, in which the sulphur compounds
are hydrogen sulphide, carbonyl sulphide, mercaptans, especially
C.sub.1-C.sub.6 mercaptans, organic sulphides, especially
di-C.sub.1-C.sub.4-alkyl sulphides, organic disulphides, especially
di-C.sub.1-C.sub.4-alkyl disulphides, thiophene compounds, aromatic
mercaptans, especially phenyl mercaptan, or mixtures thereof,
preferably mercaptans, more especially C.sub.1-C.sub.4 mercaptans,
the total amount of sulphur compounds preferably being up to 3 vol
% based on total gas stream, more preferably up till 1.5% Vol, more
preferably up till 0.1% Vol, still more preferably between 1 and
700 ppmV, most preferably between 2 and 500 ppmV.
5. A process according to claim 1, in which the gas stream also
comprises water.
6. A process according to claim 1, in which the gas stream also
comprises hydrogen sulphide and optionally carbon dioxide.
7. A process according to claim 1, in which the temperature of the
zeolite adsorption process is between 10 and 60.degree. C., the
pressure is between 10 and 150 bara, and the superficial gas
velocity is between 0.03 and 0.6.
8. A process according to claim 1, in which the temperature of the
first and second steps of the regeneration process is between 100
and 350.degree. C., and the pressure between 5 and 70 bara.
9. A process according to claim 1, in which the adsorbent(s)
comprises at least a zeolite dispersed in a binder.
10. A process according to claim 1, in which the adsorbent is in
the form of at least two beds, one bed comprising zeolite having a
pore diameter inferior or equal to 5 .ANG., preferably 3 or 4
.ANG., such as a 3 .ANG. or 4.ANG. zeolite, the second and
eventually further beds comprising at least a zeolite having a pore
diameter of more or equal to 5 .ANG..
11. A process according to claim 1, in which the regeneration steps
are carried out at a superficial gas velocity of less than 0.20
m/s.
12. A process according to claim 1, in which the regeneration gas
stream for step b) of the regeneration is a gas stream obtained by
saturating the stream with water at a temperature below the
regeneration temperature.
13. A process according to claim 1, in which the regeneration gas
stream for the step b) of the regeneration procedure has a relative
humidity between 1 and 50%.
14. A process according to claim 5, in which the water is removed
before the removal of the sulphur compounds.
15. A process according to claim 14, in which the water is removed
by adsorbing it on a zeolite having a pore diameter of inferior or
equal to 5 .ANG..
16. A process according to claim 15, in which the water is removed
by adsorbing it on a zeolite having a pore diameter of 3 to 4
.ANG..
17. A process according to claim 6, in which the carbon dioxide is
contained in the gas stream in an amount up to 2 Vol % hydrogen
sulphide.
18. A process according to claim 6, in which the carbon dioxide is
contained n the gas stream in an amount up to 0.5% Vol % hydrogen
sulphide.
19. A process according to claim 16, in which the hydrogen sulphide
and part of the carbon dioxide is removed by means of washing the
gas stream with a chemical and/or physical solvent.
20. A process according to claim 19, in which the chemical and/or
physical solvent is an aqueous alkaline solution.
21. A process according to claim 19, in which the chemical and/or
physical solvent is a aqueous amine solution.
22. A process according to claim 7, in which the superficial gas
velocity is between 0.05 and 0.40 m/s.
23. A process according to claim 11, in which the regeneration
steps are carried out at a superficial gas velocity between 0.02
and 0.15 m/s.
24. A process according to claim 11, in which the regeneration gas
stream(s) comprise nitrogen, hydrogen or a hydrocarbon gas
stream.
25. A process according to claim 24, in which the regeneration gas
stream(s) comprises a treated gas stream treated according to the
process.
Description
[0001] The present invention relates to a process for the removal
of sulphur compounds from a hydrocarbon stream, especially a
gaseous hydrocarbon stream, comprising said sulphur compounds,
which process comprises contacting said gas stream with an
adsorbent comprising a zeolitic adsorbent.
[0002] The invention further concerns a process for the
regeneration of the said adsorbent loaded with sulphur
compounds.
[0003] The removal of sulphur-containing compounds from hydrocarbon
streams comprising such compounds has always been of considerable
importance in the past and is even more so today in view of
continuously tightening process requirements and environmental
regulations. This holds not only for natural gas streams to be used
for e.g. the preparation of synthesis gas or for residential use or
to be transported as liquefied natural gas, but also for natural
gas liquid streams, natural gas condensate streams as well as for
crude oil derived refinery streams containing sulphur
compounds.
[0004] Sulphur contaminants in hydrocarbon streams include hydrogen
sulphide, carbonyl sulphide, mercaptans, sulphides, disulfides,
thiophenes and aromatic mercaptans, which due to their odorous
nature can be detected at parts per million concentration levels.
Thus, it is desirable for users of such natural gas and refinery
streams to have concentrations (typical specifications) of total
sulphur compounds lowered to e.g. less than 20 or 30 ppmV or less
than 50-75 mg S/Nm.sup.3, the amount of non-hydrogen sulphide
compounds lowered to e. g. less than 5, or even less than 2 ppmV or
less than 12 mg S/Nm.sup.3 or even less than 5 mg S/Nm.sup.3.
[0005] Numerous natural gas wells produce what is called "sour
gas", e.g. natural gas containing hydrogen sulphide, mercaptans,
sulphides and disulphides in concentrations that makes the natural
gas unsuitable for direct use. Considerable effort has been spent
to find effective and cost-efficient means to remove these
undesired compounds. In addition, the natural gas may also contain
varying amounts of carbon dioxide, which depending on the use of
the natural gas often has to be removed at least partly. Streams
used and obtained in refineries, especially hydrogen containing
streams obtained in hydrodesulphurisation processes and obtained in
hydrocarbon reforming processes as well as obtained by partial
oxidation of sulphur containing feed streams, often contain the
sulphur compounds as described before.
[0006] A number of processes are known for the removal of sulphur
compounds and optionally carbon dioxide from hydrocarbon streams.
These processes are generally based on physical and/or chemical
absorption, chemical reaction and/or solid bed adsorption. Physical
and/or chemical absorption processes, often using aqueous alkaline
solutions, usually are able to remove hydrogen sulphide and, when
carbon dioxide is present, a large amount of the carbon dioxide, in
some cases even complete removal of the carbon dioxide is obtained.
However, the complete removal of sulphur compounds as mercaptans,
sulphides and disulphides is much more difficult.
[0007] Chemically reacting processes in general are able to remove
carbon dioxide and/or hydrogen sulphide without large difficulties;
however, they suffer from the fact that they do not effectively
remove mercaptans, sulphides and disulphides and often produce
large amounts of useless waste (such as non-regenerable
adsorbents). Regenerable solid bed adsorption processes are very
suitable for the removal of the larger sulphur compounds such as
methyl mercaptan, ethyl mercaptan, normal and isopropyl mercaptan
and butyl mercaptan. For instance, WO 2004/039926 discloses such an
adsorption process carrying out a regeneration gas stream with a
water relative humidity less than 100% and in which the
degradation/ageing of the zeolitic adsorbent is significantly
reduced.
[0008] However, the regeneration of the adsorption beds is often a
considerable problem. During the regeneration of the adsorbent, a
considerable amount of regeneration gas is needed and has to be
treated by further absorption processes generally using physical
and/or chemical solvents such as in e.g. Selexol.RTM. and
Purisol.RTM. processes representing important investment and being
not commercially available everywhere in the world due to export
restrictions in order to meet the specifications in terms of
sulphur compounds for further use.
[0009] The present invention relates to a sulphur compounds removal
process that does not show the drawbacks of the prior art
processes. Furthermore, in the case of regeneration of adsorbent
loaded with these lower alkyl mercaptans, hydrothermal ageing and
the formation of carbon on the zeolite adsorbent(s) are
particularly low.
[0010] The present invention relates to a process for the removal
of sulphur compounds from a hydrocarbon stream, especially a
gaseous hydrocarbon gas stream, comprising said sulphur compounds,
which process comprises contacting said gas stream with at least an
adsorbent comprising a zeolite having a pore diameter of at least 5
.ANG. to adsorb the sulphur compounds thereon and to obtain a
treated gas, the adsorption process is followed by a regeneration
procedure of used, loaded adsorbent, characterized in that the
regeneration procedure comprises the following steps:
[0011] a/ contacting the said loaded adsorbent with a first dry gas
having a temperature within the range from 15-200.degree. C. and a
the pressure of 5-70 bara in a turn-around way by recycling the
first dry gas at least partially and preferably completely through
the adsorbent, i.e. with or without a purge of gas,
[0012] b/ then contacting the loaded adsorbent with a regeneration
gas stream having a relative water humidity between 1 and 100%
saturation, a temperature of 15-200.degree. C. and a pressure of
5-70 bara being partially recycled through the adsorbent or
not,
[0013] c/ and finally contacting the said loaded adsorbent with a
second dry gas having a temperature within the range from
50-350.degree. C. and a the pressure of 5-70 bara.
[0014] The gas streams in step a) and b) could be recycled with a
compressor and could be temperature regulated by heat-exchange.
[0015] The contacting of gas in step a) and b) may be performed in
the same flow direction as the contacting in the adsorption
process.
[0016] The temperature of the zeolite adsorption procedure may vary
between wide ranges, and is suitably between 0 and 80.degree. C.,
preferably between 10 and 60.degree. C., the pressure is suitably
between 10 and 150 bara. The superficial gas velocity is suitably
between 0.03 and 0.6 m/s, preferably between 0.05 and 0.4 m/s.
[0017] For the regeneration procedure, the regeneration gas stream
to be used may be in principle each inert gas or inert gas mixture.
Suitably nitrogen, hydrogen or a hydrocarbon gas stream, a mixture
of saturated light hydrocarbons, preferably methane, possibly
containing inert gases such as N.sub.2, CO.sub.2, Ar can be used,
preferably a treated gas stream which is obtained by a sulphur
removal process as described above.
[0018] In Natural Gas Processing units, the regeneration gas could
be e.g. the Sales Gas (product gas) containing generally above 95%
vol methane and below 5% ethane and heavier hydrocarbons, or the
demethanizer overhead from the gas fractionation part of the
Process unit or the residual gas (70% vol methane, 30% vol N2) from
the Nitrogen rejection unit in case of LNG production or the boil
off gas from LNG storages.
[0019] For the first and the third step of the regeneration
procedure, the same dry gas can be used.
[0020] For the second step of the regeneration procedure, the gas
which has a relative water humidity between 1 and 100% saturation,
preferably between 1 and 50%, may be obtained by any suitable
method. For instance, a dry gas may be mixed with a saturated gas,
or a dry gas stream is saturated followed by an increase of the
temperature. In some preferred embodiments, it can be the gas from
the first step which contains some water in the specified
range.
[0021] The third step of the regeneration procedure according to
the present invention is finalized by regeneration with a dry gas
stream. In this way the adsorption capacity is fully restored. One
advantage of the invention is that the dry gas used for the final
regeneration step can be recycled upstream the adsorption unit
reducing thus the loss of valuable product as it contains only a
very low quantity of sulphur compounds respecting the above
mentioned specifications.
[0022] In those cases in which the temperature of the regeneration
gas is above the condensation point of steam, the relative humidity
is defined as the volume percentage of the water in the gas
stream.
[0023] Very suitably the hydrocarbon stream to be treated is a
gaseous hydrocarbon stream, especially a natural gas stream, an
associated gas stream, or a refinery gas stream. Natural gas is a
general term that is applied to mixtures of inert and light
hydrocarbon components that are derived from natural gas wells. The
main component of natural gas is methane. Further, often ethane,
propane and butane are present. In some cases (small) amounts of
higher hydrocarbons may be present, often indicated as natural gas
liquids or condensates. Inert compounds may be present, especially
nitrogen, carbon dioxide and, occasionally, helium. When produced
together with oil, the natural gas is usually indicated as
associated gas.
[0024] Sulphur compounds, e.g. hydrogen sulphide, mercaptans,
sulphides, disulphides, thiophenes and aromatic mercaptans may be
present in natural gas in varying amounts. Refinery streams concern
crude oil derived gaseous hydrocarbon streams containing smaller or
larger amounts of sulphur compounds. Also recycle streams and bleed
streams of hydrotreatment processes, especially
hydrodesulphurisation processes, may be treated by the process
according to the present invention.
[0025] The process of the present invention may also be used for
the removal of the sulphur compounds from liquid hydrocarbon
streams as natural gas liquids streams, natural gas condensate
streams and crude oil derived refinery streams, especially natural
gas liquids streams and natural gas condensate streams. Natural gas
liquids are well known in the art (see for instance The Petroleum
Handbook, Elsevier, Amsterdam/London/New York, 1983, p 555) and
contain hydrocarbons heavier than methane, usually contain
C.sub.3-C.sub.12 compounds, often more than 50 weight % being
C.sub.4-C.sub.10 compounds. Natural gas liquids (NGL) are suitably
produced directly at the well head by separating the production
stream from the subsurface formation at high pressure (usually
between 40 and 90 bara) into a gaseous stream, an aqueous stream
and a liquid hydrocarbon stream (the NGL stream). Cooling the
gaseous stream usually results in a further amount of liquid
products (condensates), mostly consisting of C.sub.4-C.sub.12
compounds, usually at least 50 wt % C.sub.5+ hydrocarbons. Suitable
refinery streams are distillation fractions boiling in the naphtha,
kerosene and diesel ranges (e.g. boiling ranges between 30 and
380.degree. C.), as well as heavy gas oils and recycle oils (e.g.
boiling between 250 and 450.degree. C.).
[0026] The sulphur compounds which may be removed by the process of
the present invention are in principle all compounds which are
adsorbed by adsorbents comprising zeolites having a pore diameter
of at least 5 .ANG.. Usually the sulphur compounds are hydrogen
sulphide, carbonyl sulphide, mercaptans, especially C.sub.1-C.sub.6
mercaptans, organic sulphides, especially di-C.sub.1-C.sub.4-alkyl
sulphides, organic disulphides, especially di-C.sub.1-C.sub.4-alkyl
disulphides, thiophene compounds, aromatic mercaptans, especially
phenyl mercaptan, or mixtures thereof, preferably mercaptans, more
especially C.sub.1-C.sub.4 mercaptans.
[0027] The invention especially relates to the removal of methyl
mercaptan, ethyl mercaptan, normal- and iso-propyl mercaptan and
the four butyl mercaptan isomers.
[0028] The starting hydrocarbon stream may contain any amount of
sulphur compounds, but in general, the total amount of sulphur
compounds will be up to 3 vol % based on total gas stream, is
preferably up till 1.5 vol %, more preferably up till 0.1 vol %,
still more preferably between 1 and 700 ppmV, most preferably
between 2 and 500 ppmV. Higher amounts of sulphur, especially when
it concerns mainly hydrogen sulphide, can be removed by the process
of the present invention, but are more suitably removed by washing
processes in which chemical and/or physical solvents are used.
[0029] The starting hydrocarbon stream can be a dry hydrocarbon
stream (preferably having an amount of water.ltoreq.5 ppmV, and
more preferably.ltoreq.1 ppmV) but, especially when it is a gaseous
hydrocarbon stream, may contain a certain amount of water,
preferably up to 1% mol and more preferably less or equal to 2,000
ppm mol. Especially in the case of natural or associated gas the
stream will be saturated with water.
[0030] In the case that water is present in the hydrocarbon stream,
a more efficient process is obtained when the water is removed
before the removal of the sulphur compounds, preferably by
adsorbing the water on a zeolite having a pore diameter of less or
equal to 5 .ANG., preferably a pore diameter of 3 or 4 .ANG.. In
such preferred zeolites hardly any sulphur is adsorbed, only water
is adsorbed. In general, the capacity of such zeolites is higher
than larger pore zeolites. The amount of water to be removed may be
small or large, but preferably at least 60 weight % of the water is
removed, preferably 90 wt %, Very suitably water is removed to a
level of less than 1% mol in the treated gas, preferably less than
100 ppmV, more preferably less than 5 ppmV.
[0031] The process according to the present invention preferably
carries out an adsorbent comprising at least a zeolite dispersed in
a binder, the zeolite(s) being preferably of a zeolite type A
and/or a zeolite of type X. Such materials called also molecular
sieves are commercially available.
[0032] A further improvement of the process according to the
present invention is the use of adsorbent in the form of at least
two beds, one bed comprising a zeolite having a pore diameter
inferior or equal to 5 .ANG., preferably 3 or 4 .ANG., the second
and, if present, the further beds comprising a zeolite having a
pore diameter of at least 5 .ANG.. It is also possible to have a
"complex" bed, being an intimate mixture or a dry-blend of at least
two different adsorbents.
[0033] In a preferred embodiment, the 1.sup.st bed comprises at
least a zeolite having the pore diameter of 5 .ANG. that removes
hydrogen sulphide, methyl- and ethylmercaptan while the 2.sup.nd
bed that comprises at least a 13 X zeolite removes all higher
mercaptans and larger sulphur compounds. It will be appreciated
that the above indicated beds can be applied in one single vessel,
or may be spread over two (or even more) vessels.
[0034] In another preferred embodiment, there is another bed before
the two beds mentioned above comprising at least a 3 .ANG. and/or 4
.ANG. and/or 5 .ANG. zeolite to remove any water upstream of the
sulphur compound removal; the said further bed may be incorporated
into the above mentioned one or more vessels, or may be applied in
an additional vessel. The advantage of using more than one vessel
is that each vessel can be used at its most optimal conditions for
adsorption as well as for regeneration.
[0035] The process according to the present invention may be
carried out in a continuous mode, preferably using two or more
adsorbers comprising zeolite, at least one adsorber in an adsorbing
mode and at least one adsorber is a desorbing mode. Depending on
the actual situation there may be combinations of two, three, four
or even more adsorbers, one in absorbing mode, the others in
different stages of desorbing mode.
[0036] Especially in the case of natural and associated gas, a
considerable amount of the total amount of sulphur compounds is
formed by hydrogen sulphide. Amounts of up to 10 or even 20 vol %
or even more of hydrogen sulphide may be present. Further smaller
or larger amounts of carbon dioxide may be present. Sometimes
amounts of up to 10 or even 20 vol % or even more of carbon dioxide
may be present. Suitably the gas stream comprises hydrogen sulphide
and optionally carbon dioxide up till 2 vol % hydrogen sulphide,
more preferably up till 0.5 vol % hydrogen sulphide.
[0037] In the case that larger amounts of hydrogen sulphide are
present in the gas stream, it appears to be more efficient to
remove the hydrogen sulphide (and at least part of the carbon
dioxide) by means of a washing process, preferably prior to the
adsorption process as defined above.
[0038] In a washing process, the gas stream is washed with a
chemical and/or physical solvent, preferably an aqueous alkaline
solution, more preferably an aqueous amine solution. The use of
organic solvents or aqueous solutions of organic solvents for
removing of so-called acid gases as hydrogen sulphide and
optionally carbon dioxide and/or COS from a gas stream containing
these compounds has been described long ago. See for instance A. L.
Kohl and F. C. Riesenfeld, 1974, Gas Purification, 2.sup.nd
edition, Gulf Publishing Co. Houston and R. N. Maddox, 1974, Gas
and Liquid Sweetening, Campbell Petroleum Series. Preferably a
regenerable absorbent solvent is used in a continuous process.
[0039] On an industrial scale there are chiefly two categories of
absorbent solvents, depending on the mechanism to absorb the acidic
components: chemical solvents and physical solvents. Each solvent
has its own advantages and disadvantages as to features as loading
capacity, kinetics, regenerability, selectivity, stability,
corrosivity, heat/cooling requirements etc.
[0040] Chemical solvents which have proved to be industrially
useful are primary, secondary and/or tertiary amines derived
alkanolamines. The most frequently used amines are derived from
ethanolamine, especially monoethanol amine (MEA), diethanolamine
(DEA), triethanolamine (TEA), diisopropanolamine (DIPA) and
methyldiethanolamine (MDEA).
[0041] Physical solvents which have proved to be industrially
suitable are cyclo-tetramethylenesulfone and its derivatives,
aliphatic acid amides, N-methylpyrrolidone, N-alkylated
pyrrolidones and the corresponding piperidones, methanol, ethanol
and mixtures of dialkylethers of polyethylene glycols.
[0042] A well-known commercial process uses an aqueous mixture of a
chemical solvent, especially DIPA and/or MDEA, and a physical
solvent, preferably an alcohol, especially methanol or ethanol,
cyclo-tetramethylene sulfone or its derivatives, or N-methyl
pyrrolidone, preferably cyclo- tetramethylene sulfone. Such systems
show good absorption capacity and good selectivity against moderate
investment costs and operational costs.
[0043] Such washing processes according to absorption techniques
perform very well at high pressures, especially between 20 and 90
bara. Preferably in the hydrogen sulphide removal step at least 90
wt % of the hydrogen sulphide based on total weight of hydrogen
sulphide present in the gas stream is removed, preferably 95 wt %,
especially hydrogen sulphide is removed till a level of less than
10 ppmV, more especially to a level of less than 5 ppmV.
[0044] The adsorption process according to the present invention
allows to finish the sulphur compounds removal by concentrating the
sulphur compounds in a small quantity of regeneration gas making it
possible to mix it directly with the acid gas from the absorption
unit for further treatment for sulphur recovery.
[0045] Other solutions could be drying and sulphur compounds
condensation and then recovery of sulphur compounds in liquid
phase.
* * * * *