FIELD OF THE INVENTION
The present disclosure relates to a novel catalyst for producing higher hydrocarbons
from methane or methane derived from natural gas & process thereof. More
specifically, the disclosure relates to Molybdenum (Mo) catalyst, promoted by metal,
metal oxides or a compound thereof from Group 4, 6 or 13 of the 5 periodic table, a
process for preparing the same and a fixed bed reactor with the said catalyst.
BACKGROUND OF THE INVENTION
The global demand for petroleum crude is continuously rising due to high dependency
of the modern society on oil, gas and various other petroleum products. Natural gas
10 (methane) is considered as an alternative to petroleum for the production of chemicals
and clean liquid fuels. On an energy content basis petroleum crude costs 7 times more
than that of natural gas. While natural gas projected reserves are significantly larger,
more than 40% reserves are available at remote locations and are classified as stranded.
Major content of natural gas is methane (more than 80%), which can be potentially
15 used as a raw material for the production of higher hydrocarbons.
Reactions with methane require C-H bond activation which proceeds with a relatively
high activation energy barrier (Ea. = 435 KJ/mole) in the vapor phase. Therefore,
methane tends to remain stable and it’s conversion to commodity chemical remains a
challenge. Indirect routes of conversion of methane are suggested via the formation of
20 synthesis gas (mixture of CO and H2, syn-gas) which can be further converted into
fuels and chemicals by Fischer-Tropsch reaction. However, several factors such as the
deactivation of the catalyst and the requirement to obtain 1:1 ratio of the syn-gas are
the bottlenecks in the commercialization of this technology. Therefore, routes for
direct methane conversion to fuels and chemicals are being explored which may
25 involve an oxidative or a non-oxidative reaction environment. In an oxidative route,
3
methane conversion to hydrocarbons tends to produce side products (CO & CO2) and
coke formation, causing lesser selectivity and catalyst deactivation. In contrast, nonoxidative
route has shown considerable promise towards the development of a stable
and selective catalyst. For this purpose, molybdenum (Mo) supported on zeolites has
been suggested as an effective catalyst for non-5 oxidative methane
dehydroaromatization reaction. Several patents and publications are available in the
prior art that teach various methodologies and catalysts for non-oxidative methane
dehydroaromatization reaction. US 6,239,057, EP 2,229,349, US 6,552,243, EP
2841403, US 7888543, US 20080249342, WO 2011144319, US 20110124933 are a
10 few examples which disclose a non-oxidative methane aromatization process for
producing benzene and higher hydrocarbons, from methane or lower hydrocarbons
using transition metals of groups IIA, IIB, VB, VIB, VIIB, and VIII, alone or mixtures
thereof doped over aluminosilicates.
D. Wang et al. have reported methane conversion ranging between 4 to 8% with 60%
15 benzene selectivity at 600 to 800 0C over a 2%Mo/H-ZSM-5 catalyst (Journal of
Catalysis 169, 1997, pages 347 to 358). Q. Dong et al. study the influence of
the doping of Mo/HZSM-5 with some transition metals Fe, Cr, Ga, Co, Ni, Zn, Ti, Rh,
Re, Au and Ag as promoters. Maximum methane conversion was observed from
10 to 14%, but with high coking (selectivity above 20% up to above 60% with the
20 exception of Ga 14%). (Journal of Natural Gas Chemistry, 13 2004, pages 36 to 40).
All of the above mentioned prior arts suffer from either low yields of the desired
product, low selectively of the product, unstable catalysts and/or expensive dopants.
To overcome the stated drawbacks in the prior art it is proposed in the present
25 disclosure Molybdenum (Mo) catalyst, promoted by a combination of Cr, Ga, TiO2 or
Ti and supported on MCM-22 and/or ZSM-5 type aluminosilicates (MWW/MFI
group) and non-oxidative methane dehydro-aromatization process based on the same.
4
OBJECTIVES OF THE INVENTION
Therefore, it is an object of the present disclosure to overcome the problems in the
prior art.
It is an object of this invention to develop a selective methane dehydroaromatization
(MDA) catalyst and a 5 process thereof.
It is another object of the present invention to design a catalyst comprising an
aluminosilicate having appropriate silica to alumina ratio (SAR) which can effectively
produce paraffins, olefins & aromatics,
It is another object of the invention to design fixed bed reactor with catalyst packing
10 comprising different layers of active catalysts effective for high conversion and
product selectivity.
It is another object of the present invention to design a catalyst comprising an
aluminosilicate having appropriate silica to alumina ratio which can effectively
produce paraffins, olefins & aromatics without any deactivation in the longer run and
15 give high conversion.
These and other objects of the present invention are achieved in the preferred
embodiments disclosed below by providing a catalyst and a method thereof.
According to an embodiment the invention comprises two different layers of the
catalyst composition (i) with active molybdenum carbide or TiO2 or metallic catalyst
20 composition mentioned during this invention and/or (ii) molybdenum or molybdenum
compounds supported on aluminosilicate (MWW or MFI type zeolite) or
aluminosilicates only having suitable promoters from groups 4, 6 and 13. The order of
catalyst packing in two layers is not limited to the above mentioned order and may be
in any other order for instance in reverse.
5
According to another embodiment the present invention comprises an aluminosilicate
having a silica to alumina ratio (SAR) varying from 15 to 60, said aluminosilicate
being loaded with first metal from group VI-B or a compound thereof as the first layer
of the bed (upstream) and second a metal or a compound thereof as a promoter from
Group 13 of the periodic table as the second layer of the bed (downstream), 5 which can
effectively produce paraffins, olefins & aromatics without any deactivation in a longer
run and give high conversion.
According to another embodiment the present invention comprises an aluminosilicate
having SAR varying from 15 to 60, said aluminosilicate being loaded with
10 molybdenum (Mo) or a compound thereof as the first layer of the bed (upstream) and
a promoter metal/metal oxides or a compound thereof from Group 4 (Cr) of the
periodic table as the second layer of the bed (downstream), which can effectively
produce paraffins, olefins & aromatics.
According to another embodiment the present invention comprises an aluminosilicate
15 having SAR varying from 15 to 60, said aluminosilicate being loaded with (i)
Molybdenum or a compound thereof as the first layer of the bed (upstream) (ii) a metal,
metal oxides or a compound thereof from Group 4 (Cr) of the periodic table as a first
promoter (as the second layer of the bed (downstream)) (iii) a metal/metal oxides or a
compound thereof from Group 13 (Ga) of the periodic table as a second promoter (as
20 the third layer of the bed (downstream), which can effectively produce olefins &
aromatics.
SUMMARY OF THE INVENTION
According to an embodiment the present invention relates to catalyst composition for
conversion of methane to higher hydrocarbons, wherein said composition comprises
25 of molybdenum or molybdenum carbide compound, metal, metal oxides or a
6
compound thereof from Group 4 or 6 of the periodic table, metal, metal oxides or a
compound thereof from Group 13 of the periodic table; and aluminosilicate wherein
silica to alumina ratio (SAR) is in the range of 10 to 100.
In another embodiment, the present invention relates to a fixed bed reactor for
conversion of methane to higher hydrocarbons 5 comprising:
i. a first catalytic bed layer including molybdenum carbide, molybdenum
compound or TiO2/Ga/Cr or a mixture thereof;
ii. a second catalytic bed layer including molybdenum or molybdenum
compounds supported on aluminosilicate MCM-22 or ZSM-5 having suitable
10 promoter i.e. metal or oxide from group 4, 6, or 13 group of the periodic table
or a mixture thereof;
iii. a gas inlet for a reaction gas containing methane; and
iv. a gas outlet for higher hydrocarbons.
In an embodiment, the present invention relates to a process of making a catalyst of an
15 aluminosilicate comprising steps of:
a) pre-treating aluminosilicate by ultra-sonication and/or (b) steaming treatment;
b) loading said aluminosilicate is with metal from Group 6, Group 13 or Group 4
or a compound thereof using metal impregnation;
c) co-feeding of water, methanol/ethanol;
20 d) regeneration of coked catalyst in contact with oxygen;
wherein said aluminosilicate has silica to alumina ratio (SAR) in the range of 10 to
100 and process is carried out at predefined conditions
7
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
Some of the objects of the invention have been set forth above. These and other
objects, features, aspects and advantages of the present invention will become better
understood with regard to the following description, appended claims and
accompanying 5 drawings where:
Fig. 1 illustrates the fixed bed tubular reactor (100) with different layers of the catalyst
composition as claimed in the present invention.
DETAILED DESCRIPTION OF INVENTION
The present invention will be described with respect to preferred embodiments but the
10 invention is not limited thereto but only by the claims.
In one embodiment, the present invention relates to a catalyst composition for the
conversion of methane to higher hydrocarbons including olefin, aromatic
hydrocarbons etc. The catalyst comprises particles of a porous aluminosilicate material
associated with at least one or two catalytically active metals, metal oxides or metal
15 compounds. Said composition comprises of: molybdenum or molybdenum compound;
metal, metal oxides or a compound thereof from Group 4 or 6 of the periodic table;
metal, metal oxides or a compound thereof from Group 13 of the periodic table; and
aluminosilicate wherein silica to alumina ratio (SAR) is in the range of 10 to 100.
Activity of the catalyst may be analyzed in a continuous tubular fixed bed reactor (500
20 mm L & 15 mm ID) which holds the catalyst under suitable conditions sufficient for
methane conversion to higher hydrocarbons having at least olefinic & aromatic range
of compounds.
In one embodiment, the present invention relates to a fixed bed reactor (100) for
25 conversion of methane to higher hydrocarbons as illustrated in Fig 1 comprising:
8
• a first catalytic bed layer (105) including molybdenum carbide, molybdenum
compound or TiO2/Ga/Cr or a mixture thereof;
• a second catalytic bed layer (106) including molybdenum or molybdenum
compounds supported on aluminosilicate MCM-22 or ZSM-5 having suitable
promoter group from 5 group 4, 6, & 13;
• a gas inlet (101) for a reaction gas containing methane; and
• a gas outlet (102) for higher hydrocarbons
• thermocouple (103);
• a layer of glasswool (104);
10 • a layer of inert silicon carbide (107); and
• furnace (108).
In an embodiment reactor setup comprises a fixed bed tubular (cylindrical) vessel
having 500 mm length & 15 mm internal diameter with two defined temperature zones,
15 containing catalyst in either powdered or pellet forms through which methane feed or
major proportion of methane containing feed passes and the desired reaction goes on.
In another embodiment, the fixed bed reactor (100) may comprise two different layers
of the catalyst composition, the first layer (105) with molybdenum carbide or
molybdenum compound layer from about 0.5 mm to about 15 mm and the second layer
20 (106) of about 2 nm to about 40 nm may be molybdenum or molybdenum compounds
supported on aluminosilicate (MCM-22/ZSM-5) having suitable promoters from
groups 4, 6 and 13 or vice versa.
The reactor further comprised of a a second catalytic bed layer (106) including
25 molybdenum or molybdenum compounds supported on aluminosilicate MCM-22 or
ZSM-5 having suitable promoter group from group 4, 6, & 13, a gas inlet (101) for a
reaction gas containing methane; and a gas outlet (102) for higher hydrocarbons. The
9
reactor further comprises of a thermocouple (103), a layer of glasswool (104), furnace
(108) and a layer of inert silicon carbide (107) that works as an inert support for
catalytic bed inside the tubular fixed bed reactor.
The reaction products flowing out of the reactor are analyzed by gas 5 chromatography.
In the continuous fixed bed reactor setup, the catalyst remains fixed inside the
cylindrical vessel with the reactants & products passing through the fixed catalyst bed
and referred to as packed bed reactors.
The methane feed or methane containing feed (natural gas) contact time (residence
10 time) may range from about 0.01 second to about 75 second. Preferred contact time is
from about 3 seconds to about 6 seconds. However, longer feed contact time results
undesirable by-products and suppresses the aromatic (benzene & toluene) selectivity.
The catalyst comprises from about 1 wt% to about 8 wt% of Mo with a metal or metal
compound from group VI-B of the periodic table. Effective performance is observed
15 when concentration of Mo by wt% in the catalyst is not more than 8%. Second metal
may be taken from 4, 6 & 13 group of the periodic table, preferably TiO2, chromium
(Cr) & gallium (Ga) along with molybdenum which may show efficient methane
conversion & selectivity of olefin and aromatics. Specifically, gallium (Ga) helps to
improve the selectivity for the production of aromatics (benzene & toluene).
20 In another preferred embodiment, the present invention comprises combining titanium
(Ti) from group 4 with Mo. It is observed that this combination shows effective
methane dehydrogenation to give higher stability to the catalyst & enhances paraffin
& olefins selectivity compared to Mo catalyst supported on aluminosilicate based
zeolite. The Mo catalyst support precursor may be selected from zeolites, more
25 preferably MFI type framework, more preferably ZSM-5 and MWW type framework,
preferably MCM-22. The SiO2/Al2O3 ratio of the aluminosilicate may be suitably in
the range 10 to 100, preferably 15 to 50. Preferably some or all of the molybdenum in
10
the catalyst precursor is present in the form of an oxide. Preferably some or all of the
Ti in the catalyst precursor is present in the form of an oxide such as TiO2. Suitably
at least half, based on the total number of molybdenum ions in the catalyst precursor,
preferably substantially all, more preferably all, of the molybdenum is in the form of
5 an oxide.
The amount of Cr/Ga/TiO2 by wt% in catalyst composition may be less than the
amount of Mo, the base metal. In one of the preferred embodiment with no more than
5 wt% of Cr/Ga/TiO2 may be used. Most preferably 0.2 wt% to 2.5 wt% may be used.
In another preferred embodiment, the invention provides a TiO2 oxide promoted
10 Mo/aluminosilicate catalyst, wherein Mo may be in the range of 0.5 to 25 wt % and
TiO2 in the range of 0.01 to 30 wt % and the support aluminosilicate in the range of 8
to 99 wt %.
In another preferred embodiment, the present invention also provides a
Mo/Cr/TiO2/aluminosilicate catalyst, wherein Mo may be in the range of 0.5 to 25 wt
15 %, TiO2 in the range of 0.01 to 30 wt %, and the 3d metal (Cr) in the range of 2 to 10
wt% and aluminosilicate in the range of 8 to 99 wt %.
In the present invention, the catalyst also comprises of 60 to about 99.5 wt% of one or
more aluminosilicate materials with more preferably 90 to about 99.9 wt% support for
the transition metal. Aluminosilicates preferably have silica to alumina ratio (SAR) of
20 from about 10 to about 60 belonging to zeolites having MWW & MFI group type
framework and most preferably MCM-22 & ZSM-5. The aluminosilicate support may
be preferably used in protonic (H+) form to provide sufficient acidity for catalyzing
the said dehydroaromatization reaction.
In the present invention, addition of base metal (Mo) to the aluminosilicate support
25 may be carried out through convention wet impregnation method by taking Mo
11
precursor, preferably ammonium heptamolybdate tetrahydrate in an aqueous solution
followed by addition of this solution to aluminosilicate with continuous stirring. After
15 to 30 min stirring of this mixture, water removal may be done followed by drying
up to 10 to 15 hrs at 120 oC temperature. Calcination of the catalyst may be done within
450 to 600 oC temperature in an air atmosphere. Second metal addition 5 as promoter to
the Mo loaded aluminosilicate may be done same as above process or may be dropwise
addition of aqueous solution of desired promoter to the Mo loaded
aluminosilicate catalyst. In another embodiment, pretreatments like steaming &
sonication of the metal loaded catalysts may be done for improving the catalyst
10 performance and life of catalyst composition.
In another embodiment the present invention comprises the process of packing of
catalyst with two different layers of the catalyst composition as mentioned in the
Figure.1 (i) with active molybdenum carbide or TiO2 or metallic catalyst composition
mentioned during this invention and (ii) molybdenum or molybdenum compounds
15 supported on aluminosilicate (MWW or MFI type zeolite) or aluminosilicates only
having suitable promoters from groups 4, 6, 13 or vice versa for higher hydrocarbons
& aromatics formation. The invention is not limited to the above catalyst packing
system & process.
20 The present invention further comprises the process of making a catalyst of an
aluminosilicate having SAR varying from 15 to 60. The process of making a catalyst
comprises of steps of:
Pre-treatment of aluminosilicate (a) ultra-sonication for better dispersions of effective
metals like Mo, Cr/Ga/TiO2 over the zeolite support which gives high catalyst activity
25 and/or (b) steaming treatment for zeolite support activation regarding its acidity &
porosity before activity test.
12
After the pretreatment said aluminosilicate is loaded with (i) metal from Group 6 or a
compound thereof and (ii) a metal or a compound thereof from Group 13 of a metal of
Group 4 from the Periodic Table, which can effectively produce parafins, olefins &
aromatics without any deactivation in a longer run. The process comprises effective
metal impregnation over the aluminosilicate by conventional 5 wet impregnation
method. The addition of metal promoter to the base catalyst takes place in the same
way. In some aspects of stability & effective activity of the catalyst, this invention
comprises the pretreatment of the catalyst by methods such as sonication & steaming
effect for catalyst modifications. The process further comprises co-feeding of some
10 oxygenates such as water, methanol/ethanol with main feed, methane for effective
conversion & product selectivity. The coked catalyst is regenerated of which may be
carried out proficiently by making the catalyst in contact with oxygen gas or oxygen
containing gas in a tubular fixed bed reactor at sufficient conditions.
In one embodiment the present invention relates to a novel catalyst composition for
15 producing olefinic and aromatic hydrocarbons from pure methane feed or feed
containing major portion of methane and process thereof. The catalyst composition
used is effective for methane conversion to olefin & aromatic hydrocarbons at a
temperature of about 500 to about 1000 oC preferably 600 to 7000 C and a pressure of
about 1 bar to about 10 bars, preferably 1 to 2 bar pressure using olefin (ethylene) &
20 aromatics (benzene/toluene).
The invention will now be explained by the following examples which are only
instructive and therefore should not be construed to limit the scope of the invention.
EXAMPLES
13
For the following examples, Mo doped MCM-22 and ZSM-5 were prepared by
impregnating ZSM-5 and MCM-22 zeolites respectively, according to conventional
impregnation techniques as follows:
Ammonium heptamolybedate tetrahydrate as a source of Mo was used preferably for
5 to 15 wt% loading over MFI and MWW type framework aluminosilicate 5 with SAR-
55 and SAR-30 respectively. Loading of Mo may be done by wet impregnation or
some other method like wet ion exchange & core shell method. Catalyst drying has
been done within temperature range at 80 to 120 °C for 12 to 14 hrs. The catalyst
composition was then calcined within 400 to 1000 °C temperature range for 5 to 8 hrs.
10 2 to 3 gm of the given catalyst composition is used for activity. The source of natural
gas used having the major component more than 80% was methane. The natural gas
also contained slightly C2, C3, and C4 hydrocarbons, CO2 and nitrogen gas.
Example-1
Natural gas having major fraction of Methane was used as the feed gas and was passed
15 through a catalyst bed as illustrated in FIG. 1. Molybdenum carbide (active moiety for
the desired reaction) was placed at the first layer of the catalyst bed and double amount
of Mo/MCM-22 (SAR-55) was placed as the second layer of the catalyst bed. The
reaction conditions were maintained at a temperature of about 600 to 800° C with
normal atmospheric pressure, and a flow rate of the natural gas of about with 600 to
20 1000 ml/hgcat GHSV.
Example -2
In this example, the reaction gas, catalysts used and reaction conditions were the same
as in Example 1, except that in the catalyst bed Mo/MCM-22 (SAR-55) with Ga at the
14
bottom of the bed layer (downstream) and Molybdenum carbide was placed at the top
of the bed layer (upstream).
Example -3
In this example, the reaction gas, catalysts used and reaction conditions were the same
as in Example 1, except that in the catalyst bed Mo/MCM-22 (SAR-5 55) with Cr at the
bottom of the bed layer (downstream) and Molybdenum carbide was placed at the top
of the bed layer (upstream).
Example - 4
10 In this example, the reaction gas, catalysts used and reaction conditions were the same
as in Example 1, except that in the catalyst bed Mo/MCM-22 (SAR-55) with both Ga
& Cr at the bottom of the bed layer (downstream) and Molybdenum carbide was placed
at the top of the bed layer (upstream).
Example -5
15 In this example, TiO2 promoted Mo/ZSM-5 (SAR-55) was placed at the bottom of the
bed layer (downstream) whereas top layer of the bed (upstream) was same as
mentioned in Example-1. Also the reaction gas and reaction conditions were the same
as in Example 1.
20 Example - 6
In this example, the natural gas, catalysts composition used and reaction conditions
were the same as mentioned in Example 1, except that in the catalyst bed layer,
15
Mo/ZSM-5 (SAR-55) with TiO2 was placed on top of the catalyst bed layer and
molybdenum carbide was placed at the bottom.
Example -7
In this example, the reaction gas, catalysts used and reaction conditions were the same
as in Example 1, except that in the catalyst bed Mo/ZSM-5 (SAR-5 55) with TiO2 and
Molybdenum carbide were mixed with one another. Thus, the reaction gas came into
contact with the two catalysts at about the same location in the flow path.
Example -8
10 In this example, the natural gas, catalysts composition used and reaction conditions
were the same as mentioned in Example 1, except the support aluminosilicates i.e. in
the catalyst bed layer, 2%TiO2-5%Mo/MCM-22, SAR-55 was placed on bottom of the
catalyst bed layer downstream and Molybdenum carbide was placed at the top of the
bed (upstream).
15 Example -9
In this example, the reaction gas, reaction conditions & catalyst composition were the
same as in Example 3, except the support (aluminosilicate) SAR value (30)
Example -10
20 In this example, the reaction gas, reaction conditions & catalyst composition were the
same as in Example 5, except the support (aluminosilicate) SAR value (30).
Example -11
16
In this example, catalyst composition used (at the bottom of the bed layer) and reaction
conditions were the same as in Example 2, except the reaction gas (which has a
specified composition as 85% methane, 7% ethane, 3% propane, 1% butane, 3%
carbon dioxide & 1% nitrogen).
5
Example -12
In this example, catalyst composition used (at the bottom of the bed layer) and reaction
conditions were the same as in Example 4, except the reaction gas (which has a
specified composition as 85% methane, 7% ethane, 3% propane, 1% butane, 3%
10 carbon dioxide & 1% nitrogen).
Example- 13
In this example, catalyst composition used (at the bottom of the bed layer) and reaction
conditions were the same as above. The synthesized catalyst (TiO2/Mo/ZSM-5) was
15 characterized by X-ray diffraction pattern Scanning Electron Microscope (SEM), and
Transmission Electron Microscope (TEM) & BET surface area analyzer.
Example-14
The present example describes the methane conversion to value added products using
Cr promoted Mo/MCM-22 catalyst, more preferably 2wt%Cr/5wt%Mo/MCM-22.
20 Results have been shown in Table 1.
25
( / )
( / . )
( )
cat
cat
Volumetric flow rate of methane ml h
GHSV ml h g
Catalyst weight g
=
4 4
4
(%) 100
Moles of CH in Moles of CH out
Methane conversion
Moles of CH in
−
= ×
17
5
Table.1
Catalyst composition Methane
Conversio
n (%)
Paraffins
(Selectivit
y %)
Olefins
(Selectivit
y %)
Aromatics
(Selectivit
y %)
5%Mo/HMCM-22 12 - - -
2%Ga/5%Mo/HMCM-22 20 5 (Ethane) 10
(Ethylene)
60
(Benzene)
2%Cr/5%Mo/HMCM-22 22 8 (Ethane) 65
(Ethylene)
20
(Benzene)
2%Cr/2%Ga/5%Mo/HMC
M-22
18 32
(Pentane)
4
(Ethylene)
12
(Benzene)
4
100
moles of product formed
Selectivity
moles of CH reacted

= ×

18

We Claim:
1. A catalyst composition for conversion of methane to higher hydrocarbons,
wherein said composition comprises of:
i. molybdenum or molybdenum carbide compound;
ii. metal, metal oxides or a compound thereof from Group 5 4 or 6 of the
periodic table;
iii. metal, metal oxides or a compound thereof from Group 13 of the
periodic table; and
iv. aluminosilicate wherein silica to alumina ratio (SAR) is in the range
10 of 10 to 100.
2. The catalyst composition as claimed in claim 1, wherein said metal, metal
oxides or a compound from Group 4 of the periodic table is preferably titanium
(Ti).
15
3. The catalyst composition as claimed in claim 1, wherein said metal, metal
oxides or a compound from Group 6 of the periodic table is preferably
Chromium (Cr).
20 4. The catalyst composition as claimed in claim 1, wherein said metal, metal
oxides or a compound from Group 13 of the periodic table is preferably
Gallium (Ga).
5. The catalyst composition as claimed in claim 1, wherein said molybdenum or
25 molybdenum compound comprise 0.5-25% wt. of the catalyst.
20
6. The catalyst composition as claimed in claim 1, wherein said metal, metal
oxides or a compound comprise 0.01-30% wt. of the catalyst.
7. The catalyst composition as claimed in claim 1, wherein said aluminosilicate
comprise 8-99% wt. 5 of the catalyst.
8. A fixed bed reactor for conversion of methane to higher hydrocarbons
comprising:
10 i. a first catalytic bed layer including molybdenum carbide,
molybdenum compound or TiO2/Ga/Cr or a mixture thereof;
ii. a second catalytic bed layer including molybdenum or
molybdenum compounds supported on aluminosilicate MCM-22 or
ZSM-5 having suitable promoter i.e. metal or oxide from group 4,
15 6, or 13 group of the periodic table or a mixture thereof;
iii. a gas inlet for a reaction gas containing methane; and
iv. a gas outlet for higher hydrocarbons.
9. The fixed bed reactor as claimed in claim 8, wherein the first catalytic bed layer
20 has a thickness ranging between 0.5 mm to 15 mm.
10. The fixed bed reactor as claimed in claim 8, wherein the second catalytic
bed layer has a thickness ranging between 2 mm to 50 mm.
25 11. The fixed bed reactor as claimed in claim 8, wherein the reactor is tubular
in shape, has a length of 500 mm, and has an internal diameter of 15 mm.
21
12. The fixed bed reactor as claimed in claim 8, wherein the temperature of the
reactor is maintained in the range of 500 °C to 1000 °C.
13. The fixed bed reactor as claimed in claim 1, wherein the pressure of the
reaction gas is maintained in the range of 5 1 bar to 10 bar.
14. The fixed bed reactor as claimed in claim 1, wherein the contact time of
reaction gas with the catalytic reactor beds is in the range of 0.01 seconds
to 75 seconds.
10
15. The fixed bed reactor as claimed in claim 1, wherein the flow rate of the
reaction gas is in the range of 600 ml/hgcat to 1000 ml/hgcat.
16. The fixed bed reactor as claimed in claim 1, wherein the first catalytic bed
15 layer and the second catalytic bed layer are in either a powder form or a
pellet form.
17. The fixed bed reactor as claimed in claim 1, wherein the reaction gas has a
composition of 85% methane, 7% ethane, 3% propane, 1% butane, 3%
20 carbon dioxide, and 1% nitrogen.
18. A process of making a catalyst of an aluminosilicate comprising steps of:
a) pre-treating aluminosilicate by ultra-sonication and/or (b) steaming
treatment;
25 b) loading said aluminosilicate is with metal from Group 6, Group 13 or
Group 4 or a compound thereof using metal impregnation;
c) co-feeding of water, methanol/ethanol;
d) regeneration of coked catalyst in contact with oxygen;
22
wherein said aluminosilicate has silica to alumina ratio (SAR) in the range
of 10 to 100 and process is carried out at predefined conditions.
19. The process as claimed in claim 18 wherein said predefined conditions are
temperature in the range of 600 -800° C, normal atmospheric 5 pressure, and
a flow rate of the natural gas of 600 to 1000 ml/hgcat GHSV.