Title of Invention	A PROCESS FOR THE PREPARATION OF A CATALYST, USEFUL FOR THE PRODUCTION OF HYDROCARBONS FROM SYNTHESIS GAS
Abstract	A process for the preparation of a catalyst, useful for the production of hydrocarbons from synthesis gas, has been described. The process comprises heating, under constant stirring, an aqueous solution of a mix of 86 to 96 wt % ferric nitrate, 1 to 10 wt % copper nitrate and 1 to 4 wt % manganese nitrate. Addition of pre-heated sodium carbonate solution to the resulting mixture of aqueous solutions of nitrates under constant stirring till it becomes neutral. Continuing the addition of sodium carbonate and simultaneously adding preheated bentonite slowly, under stirring, till the pH of the solution reaches between 8 and 9. Filtering the precipitate and washing the same with warm water till the washings are nitrate free. Addition of potassium hydroxide to the precipitate followed by through kneading to ensure uniform distribution of the potassium salt. Drying the resultant product in an air oven. Cooling the resultant product to room temperature. Extruding to at least 1/4" size. Drying the extrudes and sizing to at least +6 to -14 mesh BSS. The process is simple and environment friendly and provides a catalyst of high yielding nature having high selectivity. The catalyst finds usage in synthesising hydrocarbons, particularly wax, using Fisher-Tropsch synthesis.

Title of Invention

A PROCESS FOR THE PREPARATION OF A CATALYST, USEFUL FOR THE PRODUCTION OF HYDROCARBONS FROM SYNTHESIS GAS

Abstract

A process for the preparation of a catalyst, useful for the production of hydrocarbons from synthesis gas, has been described. The process comprises heating, under constant stirring, an aqueous solution of a mix of 86 to 96 wt % ferric nitrate, 1 to 10 wt % copper nitrate and 1 to 4 wt % manganese nitrate. Addition of pre-heated sodium carbonate solution to the resulting mixture of aqueous solutions of nitrates under constant stirring till it becomes neutral. Continuing the addition of sodium carbonate and simultaneously adding preheated bentonite slowly, under stirring, till the pH of the solution reaches between 8 and 9. Filtering the precipitate and washing the same with warm water till the washings are nitrate free. Addition of potassium hydroxide to the precipitate followed by through kneading to ensure uniform distribution of the potassium salt. Drying the resultant product in an air oven. Cooling the resultant product to room temperature. Extruding to at least 1/4" size. Drying the extrudes and sizing to at least +6 to -14 mesh BSS. The process is simple and environment friendly and provides a catalyst of high yielding nature having high selectivity. The catalyst finds usage in synthesising hydrocarbons, particularly wax, using Fisher-Tropsch synthesis.

Full Text	The present invention relates to a process for the preparation of a catalyst, useful for the production of hydrocarbons from synthesis gas. The present invention particularly relates to the preparation of a catalyst for the production of wax from synthesis gas. The catalyst of the present invention finds usage in synthesising hydrocarbons, particularly wax, using Fisher-Tropsch synthesis. Synthesis gas, or "syngas", is a mixture of gases prepared as feedstock for a chemical reaction; for example, carbon monoxide and hydrogen to make hydrocarbons or organic chemicals, or hydrogen and nitrogen to make ammonia. The studies on synthetic hydrocarbon production from synthesis gas have been initiated since1902. Investigations are on world wide to improve the productivity and selectivity of the catalyst necessary for the process. Mainly metals from group VIII of the periodic table such as iron, cobalt, nickel, platinum, ruthenium are used to prepare a catalyst for the process. Out of all these metals mentioned to prepare a suitable catalyst for the production of hydrocarbons with high yield of wax fraction from synthesis gas, iron is the cheapest, is active with hydrogen / carbon monoxide ratio of the feed synthesis gas around 1, which is obtained by coal gasification and available in plenty. Iron metal in combination with one or more elements like copper, calcium, magnesium, potassium are used in the preparation of the catalyst for the production of hydrocarbons containing wax fraction. Such catalysts additionally incorporate silica or kieselghur, a naturally occurring siliceous material as catalyst support. Thus, earlier such a catalyst e.g iron incorporating copper and potassium used to be prepared from the nitrate solution of iron and copper and co-precipitating them with sodium / potassium carbonate over silica or kieselghur. The important ingredient silica / kieselghur have certain limitations. Silica preparation is a laborious method and kieselghur being a naturally occurring siliceous material is not available everywhere. The yield of wax from synthesis gas using silica or kieselghur supported iron catalyst in the fixed bed reactor system has been reported as low. The conversion of synthesis gas obtained from carbonaceous source like coal, natural gas, associated gas, refinery of gas, bio-gas to synthetic hydrocarbons is a versatile process. By using group VII metals in combination with elements from certain other groups as catalyst and wide range of operating conditions such as temperature in the range of 100 to 400 degree Celsius, pressure in the range of 1 to 1000 kg per square centimeter, space velocity in the range of 100 to 30000 per hour and hydrogen / carbon monoxide ratio in the range of 0.5 to 3.5; a wide variety of end products like methane, iso-paraffins, synthetic liquid fuels, wax, methanol, higher alcohols can be obtained. Reference may be made to U.S. patent no. 4086262, which describes the use of a catalyst obtained by mixing mechanically the carbon monoxide reducing catalyst and a specified zeolite used in the two-stage process. Single stage processes for producing hydrocarbons selectively with a specified boiling point range from synthesis gas have been reported. Reference may be made to another U.S. patent no. 4157338, which describes the use of a catalyst obtained by supporting a carbon monoxide reducing metal or metal oxide on a specified zeolite. In the above reffered processes, the product is limited by the shape selectivity of a zeolite with specified pores as a constitutional component of the catalyst so that products having a larger molecular size than the pore diameter are hardly formed and hydrocarbons having a smaller molecular size and boiling point range of gasoline or less can selectively be obtained. The one-stage process is a more economical process than the two-stage process because of its simplified process. However, the above described onestage process using the mechanically mixed catalyst is inferior to the two-stage process because of the catalytic defects that the conversion of carbon monoxide and the yield of gasoline are low and there is formed a large amount of methane which is only estimated as a fuel gas. In another one-stage process using the catalyst obtained by supporting a metal capable of exhibiting a Fischer-Tropsch activity on a particular zeolite aims at subjecting the synthesis gas to a Fischer-Tropsch reaction by the metallic component in the catalytic composition to form a hydrocarbon mixture distributed from methane to waxes as an intermediate and then converting these hydrocarbons into hydrocarbons having a boiling point range of gasoline or less by the shape selectivity zeolite known to be effective for cracking waxes, i.e. ZSM-5 catalyst. This catalyst is not useful because it loses the activity through heating at a temperature above 300 degree Celsius in an oxidizing atmosphere and thus it cannot be regenerated. Reference may be made to US Patent No.4622308, wherein an improved catalyst suitable for use in the production of hydrocarbons from the synthesis gas has been described which comprises an iron-containing Fischer-Tropsch catalyst, a zeolite and at least one metal selected from the group consisting of ruthenium, rhodium, platinum, palladium, iridium, cobalt and molybdenum. This catalyst gives a high CO conversion and hydrocarbons enriched with C5+ gasoline fraction. Reference may be made to US Patent No.4665042, wherein a catalyst system has been described which is suitable for the conversion of synthesis gas to hydrocarbons, more particularly to a catalyst system comprising a coppercontaining component together with an iron-containing component and a wax cracking component such as a Zeolite. However a significant proportion of the hydrocarbon product is in the form of methane rather than wax and this is a disadvantage because the present need is wax, mainly. Reference may be made to US Patent No.4086262, wherein a process is disclosed for the conversion of synthesis gas using a single stage process wherein the catalyst is a mixture of (i) a carbon monoxide reducing catalyst such as a methanol catalyst or an iron-containing Fischer-Tropsch catalyst and (ii) a ZSM-5 type Zeolite. However, the products described in this patent contain significant amounts of gaseous hydrocarbons, particularly methane which in all cases exceeds 10 percent by weight of the hydrocarbon product. The main object of the present invention is to provide a process for the preparation of a catalyst, useful for the production of hydrocarbons from synthesis gas, which obviates the drawbacks of the hitherto known prior art as detailed above. Another object of the present invention is to provide a process for the preparation of an improved iron catalyst using alternative naturally occurring siliceous material, bentonite as support in place of silica and kieselghur to obtain wax from the synthesis gas. Yet another object of the present invention is to provide a process for the preparation of a catalyst having high selectivity. Still another object of the present invention is to provide a process for the preparation of a catalyst of high yielding nature. Still yet another object of the present invention is to provide a process which is simple and environment friendly. In the present invention there is provided a process for the preparation of a catalyst, useful for the production of hydrocarbons from synthesis gas, which involves heating at a temperature in the range of 70 to 85 degree Celsius, under constant stirring, an aqueous solution of a mix of 86 to 96 wt % ferric nitrate, 1 to 10 wt % copper nitrate and 1 to 4 wt % manganese nitrate. Addition of preheated sodium carbonate solution to the resulting mixture of aqueous solutions of nitrates at a temperature in the range of 70 to 85 degree Celsius under constant stirring till it becomes neutral. Continuing the addition of sodium carbonate and simultaneously adding pre-heated bentonite slowly, under stirring, till the pH of the solution reaches between 8 and 9. Continuing the stirring for a time period in the range of 20 to 40 minutes after addition of sodium carbonate is stopped. Filtering the precipitate and washing the same with warm water till the washings are nitrate free. Addition of potassium hydroxide to the precipitate followed by thorough kneading to ensure uniform distribution of the potassium salt. Drying the resultant product at a temperature in the range of 70 to 90 degree Celsius for a time period in the range of 10 to 16 hours in an air oven. Cooling the resultant product to room temperature. Extruding to at least V4" size. Drying the extrudes at 105±5 degree Celsius for a time period in the range of 20 to 30 hours and sizing to at least +6 to -14 mesh BSS. Accordingly the present invention provides a process for the preparation of a catalyst, useful for the production of hydrocarbons from synthesis gas which comprises heating under constant stirring an aqueous solution of a mixture of ferric nitrate in the range of 86 to 96 wt %, copper nitrate in the range of 1 to 10 wt % and manganese nitrate in the range of 1 to 4 wt %, at a temperature in the range of 70 to 85 degree Celsius; adding pre-heated sodium carbonate solution to the resulting mixture at a temperature in the range of 70 to 85 degree Celsius under constant stirring till it becomes neutral; continuing the addition of sodium carbonate solution and simultaneously adding pre-heated bentonite slowly, under stirring, till the pH of the solution reaches between 8 and 9; continuing the stirring for a time period in the range of 20 to 40 minutes after addition of sodium carbonate is stopped; filtering the precipitate and washing the same with warm water till the washings are nitrate free; adding potassium hydroxide to the precipitate followed by thorough kneading to ensure uniform distribution of the potassium salt; drying the resultant product at a temperature in the range of 70 to 90 degree Celsius for a time period in the range of 10 to 16 hours in an air oven; cooling the resultant product to room temperature; extruding to at least %" size; drying the extrudes at 105 ±5 degree Celsius for a time period in the range of 20 to 30 hours and sizing to at least +6 to -14 mesh BSS. In an embodiment of the present invention, the aqueous solutions of the nitrates are made with de-mineralised water. In another embodiment of the present invention, the amount of de-mineralised water used is in the range of 4 to 6 times of the total amount of nitrates (w/w). In yet another embodiment of the present invention, the sodium carbonate* solution used is of at least 3.5 molar. In still another embodiment of the present invention, the bentonite is pre-heated at a temperature in the range of 350 to 500 degree Celsius for a time period in the range of 1 to 3 hours. In still yet another embodiment of the present invention, brown ring test is performed to check for the presence of nitrate in the washings. The novelty of the present invention resides in providing a process for the preparation of a catalyst, useful for the production of hydrocarbons from synthesis gas, wherein the process is simple and environment friendly and the catalyst obtained is of high yielding nature and has high selectivity. The novelty of the present invention has been achieved by the non-obvious inventive step wherein naturally occuring siliceous material, bentonite has been incorporated as support in place of silica and kieselghur, in an environment friendly manner unlike prior art processes The non-obvious inventive process step of using naturally occurring siliceous material, bentonite as support in place of silica and kieselghur, has made it possible for the present invention to provide a novel simple and environment friendly process for the preparation of an improved iron catalyst of high yielding nature and having high selectivity to obtain wax from synthesis gas. The details of the process steps of the present invention are: 1. Preparing an aqueous solution of a mix of 86 to 96 wt % ferric nitrate, 1 to 10 wt % copper nitrate and 1 to 4 wt % manganese nitrate in demineralised water of amount which is 4 to 6 times of the total amount of nitrates (w/w). 2. Heating the aqueous solution nitrates, obtained in step 1, under constant stirring at a temperature in the range of 70 to 85 degree Celsius. 3. Adding pre-heated sodium carbonate solution, of at least 3.5 molar, to the resulting mixture of heated aqueous solution of nitrates at a temperature in the range of 70 to 85 degree Celsius under constant stirring till it becomes neutral. 4. Continuing the addition of sodium carbonate and simultaneously adding under stirring pre-heated bentonite slowly till the pH of the solution reaches between 8 and 9. The bentonite is pre-heated to a temperature in the range of 350 to 500 degree Celsius for a time period in the range of 1 to 3 hours. 5. After addition of sodium carbonate is stopped, the stirring is continued for a time period in the range of 20 to 40 minutes. 6. Filtering the precipitate and washing the same with warm water having temperature of around 50 degree Celsius till the washings are nitrate free. Brown ring test is performed to check for the presence of nitrate in the washings. 7. Adding potassium hydroxide to the precipitate followed by thorough kneading to ensure uniform distribution of the potassium salt. 8. Drying the resultant product, obtained in step 7, at a temperature in the range of 70 to 90 degree Celsius for a time period in the range of 10 to 16 hours in an air oven. 9. Cooling the resultant product to room temperature. 10. Extruding to at least 1/4" size. 11. Drying the extrudes at a temperature of 105+5 degree Celsius for a time period in the range of 20 to 30 hours. 12. Sizing to at least +6 to -14 mesh BSS. The following examples are given by way of illustration of the process in actual practice and should not be construed to limit the scope of the present invention. Example-1 750 grams of ferric nitrate, 79.1 grams of copper nitrate and 22 grams of manganese nitrate were weighed separately and dissolved together in 4522 ml of de-mineralised water. This nitrate solution was heated to 80 degree Celsius under constant stirring. 1200 ml of 3.5 molar sodium carbonate solution was heated to 80 degree Celsius separately and was added to the nitrate solution at 80 degree Celsius under constant stirring. When solution became neutral, 31.2 grams of bentonite, which was pre-heated earlier to 450 degree Celsius for 2 hours, was added slowly under stirring while the addition of sodium carbonate continued till pH was in between 8 and 9. At this stage, addition of sodium carbonate was stopped and stirring continued for 30 minutes. The precipitate was filtered and washed with warm water ( 50 degree Celsius ) till it was nitrate free. The nitrate test was carried out by the brown ring test. To this nitrate free mass, 6 grams of potassium hydroxide was added and the precipitate was kneaded thoroughly for uniform distribution of the potassium salt. The final product was dried at 80 degree Celsius for 14 hours in an air oven. It was cooled to room temperature and extruded to 1/4" size extrudates which were further dried at 105 ± 5 degree Celsius for 26 hours. The extrudates were sized to +6 to-14 mesh BSS. Example-2 725 grams of ferric nitrate, 8.2 grams of copper nitrate and 23 grams of manganese nitrate were weighed separately and dissolved together in 4522 ml of de-mineralised water. This nitrate solution was heated to 85 degree Celsius under constant stirring. 1200 ml of 3.5 molar sodium carbonate solution was heated to 85 degree Celsius separately and was added to the nitrate solution at 85 degree Celsius under constant stirring. When solution became neutral, 31.2 grams of bentonite, which was preheated earlier to 450 degree Celsius for 2 hours, was added slowly under stirring while the addition of sodium carbonate continued till pH was in between 8 and 9. At this stage, addition of sodium carbonate was stopped and stirring continued for 30 minutes. The precipitate was filtered and washed with warm water ( 50 degree Celsius ) till it was nitrate free. The nitrate test was carried out by the brown ring test. To this nitrate free mass, 6 grams of potassium hydroxide was added and the precipitate was kneaded thoroughly for uniform distribution of the potassium salt. The final product was dried at 85 degree Celsius for 14 hours in an air oven. It was cooled to room temperature and extruded to 1/4" size extrudates which were further dried at 105 ± 5 degree Celsius for 26 hours. The extrudates were siz.ed to +6 to -14 mesh BSS. Example-3 750 grams of ferric nitrate, 79.1 grams of copper nitrate and 22 grams of manganese nitrate were weighed separately and dissolved together in 4522 ml of de-mineralised water. This nitrate solution was heated to 75 degree Celsius under constant stirring. 1200 ml of 3.5 molar sodium carbonate solution was heated to 75 degree Celsius separately and was added to the nitrate solution at 75 degree Celsius under constant stirring. When solution became neutral, 31.2 grams of bentonite, which was preheated earlier to 450 degree Celsius for 2 hours, was added slowly under stirring while the addition of sodium carbonate continued till pH was in between 8 & 9. At this stage, addition of sodium carbonate was stopped and stirring continued for 30 minutes. The precipitate was filtered and washed with warm water ( 50 degree Celsius ) till it was nitrate free. The nitrate test was carried out by the brown ring test. To this nitrate free mass, 5 grams of potassium hydroxide was added and the precipitate was kneaded thoroughly for uniform distribution of the potassium salt. The final product was dried at 75 degree Celsius for 14 hours in an air oven. It was cooled to room temperature and extruded to 1/4" size extrudates which were further dried at 105 ± 5 degree Celsius for 23 hours. The extrudates were sized to =6 -14 mesh BSS. The main advantages of the present invention are: 1. The process obviates the drawbacks of the hitherto known prior art as detailed above. 2. The a process provides an improved iron catalyst using alternative naturally occurring siliceous material, bentonite as support in place of silica and kieselghur to obtain wax from synthesis gas. 3. The process provides a catalyst having high selectivity. 4. The process provides a catalyst of high yielding nature. 5. The process is simple and environment fondly. We claim: 1. A process for the preparation of a catalyst, useful for the production of hydrocarbons from synthesis gas which comprises heating under constant stirring an aqueous solution of a mixture of ferric nitrate in 86 to 96 wt %, copper nitrate in the range of 1 to 10 wt % and manganese nitrate in the range of 1 to 4 wt %, at a temperature in 70 to 85 degree Celsius; adding pre-heated sodium carbonate solution to the resulting mixture at a temperature in the range of 70 to 85 degree Celsius under constant stirring till it becomes neutral; continuing the addition of sodium carbonate solution and simultaneously adding pre-heated bentonite slowly, under stirring, till the pH of the solution reaches between 8 and 9; continuing the stirring for a time period in the range of 20 to 40 minutes after addition of sodium carbonate is stopped; filtering the precipitate and washing the same with warm water till the washings are nitrate free; adding potassium hydroxide to the precipitate followed by thorough kneading to ensure uniform distribution of the potassium salt; drying the resultant product at a temperature in the range of 70 to 90 degree Celsius for a time period in the range of 10 to 16 hours in an air oven; cooling the resultant product to room temperature; extruding to 1/4" size; drying the extrudes at 105 ±5 degree Celsius for a time period 20 to 30 hours and sizing to at least +6 to -14 mesh BSS. 2 . A process as claimed in claiml-2, wherein the amount of de-mineralised water used is 4 to 6 times of the total amount of nitrates (w/w). 3. A process as claimed in claim1-3, wherein the sodium carbonate solution used is of 3.5 molar. 5. A process as claimed in claim1-4, wherein the bentonite is pre-heated at a temperature in the range of 350 to 500 degree Celsius for a time period in the range of 1 to 3 hours. 6. A process for the preparation of a catalyst, useful for production of hydrocarbons from synthesis gas, substantially as herein described with reference to the examples.

Full Text

The present invention relates to a process for the preparation of a catalyst, useful
for the production of hydrocarbons from synthesis gas. The present invention
particularly relates to the preparation of a catalyst for the production of wax from
synthesis gas.
The catalyst of the present invention finds usage in synthesising hydrocarbons,
particularly wax, using Fisher-Tropsch synthesis.
Synthesis gas, or "syngas", is a mixture of gases prepared as feedstock for a
chemical reaction; for example, carbon monoxide and hydrogen to make
hydrocarbons or organic chemicals, or hydrogen and nitrogen to make ammonia.
The studies on synthetic hydrocarbon production from synthesis gas have been
initiated since1902. Investigations are on world wide to improve the productivity
and selectivity of the catalyst necessary for the process. Mainly metals from
group VIII of the periodic table such as iron, cobalt, nickel, platinum, ruthenium
are used to prepare a catalyst for the process. Out of all these metals mentioned
to prepare a suitable catalyst for the production of hydrocarbons with high yield of
wax fraction from synthesis gas, iron is the cheapest, is active with hydrogen /
carbon monoxide ratio of the feed synthesis gas around 1, which is obtained by
coal gasification and available in plenty. Iron metal in combination with one or
more elements like copper, calcium, magnesium, potassium are used in the
preparation of the catalyst for the production of hydrocarbons containing wax
fraction. Such catalysts additionally incorporate silica or kieselghur, a naturally
occurring siliceous material as catalyst support. Thus, earlier such a catalyst e.g
iron incorporating copper and potassium used to be prepared from the nitrate
solution of iron and copper and co-precipitating them with sodium / potassium
carbonate over silica or kieselghur. The important ingredient silica / kieselghur
have certain limitations. Silica preparation is a laborious method and kieselghur
being a naturally occurring siliceous material is not available everywhere. The
yield of wax from synthesis gas using silica or kieselghur supported iron catalyst
in the fixed bed reactor system has been reported as low.
The conversion of synthesis gas obtained from carbonaceous source like coal,
natural gas, associated gas, refinery of gas, bio-gas to synthetic hydrocarbons is
a versatile process. By using group VII metals in combination with elements from
certain other groups as catalyst and wide range of operating conditions such as
temperature in the range of 100 to 400 degree Celsius, pressure in the range of 1
to 1000 kg per square centimeter, space velocity in the range of 100 to 30000
per hour and hydrogen / carbon monoxide ratio in the range of 0.5 to 3.5; a wide
variety of end products like methane, iso-paraffins, synthetic liquid fuels, wax,
methanol, higher alcohols can be obtained.
Reference may be made to U.S. patent no. 4086262, which describes the use of
a catalyst obtained by mixing mechanically the carbon monoxide reducing
catalyst and a specified zeolite used in the two-stage process.
Single stage processes for producing hydrocarbons selectively with a specified
boiling point range from synthesis gas have been reported. Reference may be
made to another U.S. patent no. 4157338, which describes the use of a catalyst
obtained by supporting a carbon monoxide reducing metal or metal oxide on a
specified zeolite.
In the above reffered processes, the product is limited by the shape selectivity of
a zeolite with specified pores as a constitutional component of the catalyst so
that products having a larger molecular size than the pore diameter are hardly
formed and hydrocarbons having a smaller molecular size and boiling point
range of gasoline or less can selectively be obtained.
The one-stage process is a more economical process than the two-stage
process because of its simplified process. However, the above described onestage
process using the mechanically mixed catalyst is inferior to the two-stage
process because of the catalytic defects that the conversion of carbon monoxide
and the yield of gasoline are low and there is formed a large amount of methane
which is only estimated as a fuel gas.
In another one-stage process using the catalyst obtained by supporting a metal
capable of exhibiting a Fischer-Tropsch activity on a particular zeolite aims at
subjecting the synthesis gas to a Fischer-Tropsch reaction by the metallic
component in the catalytic composition to form a hydrocarbon mixture distributed
from methane to waxes as an intermediate and then converting these
hydrocarbons into hydrocarbons having a boiling point range of gasoline or less
by the shape selectivity zeolite known to be effective for cracking waxes, i.e.
ZSM-5 catalyst. This catalyst is not useful because it loses the activity through
heating at a temperature above 300 degree Celsius in an oxidizing atmosphere
and thus it cannot be regenerated.
Reference may be made to US Patent No.4622308, wherein an improved
catalyst suitable for use in the production of hydrocarbons from the synthesis gas
has been described which comprises an iron-containing Fischer-Tropsch
catalyst, a zeolite and at least one metal selected from the group consisting of
ruthenium, rhodium, platinum, palladium, iridium, cobalt and molybdenum. This
catalyst gives a high CO conversion and hydrocarbons enriched with C5+
gasoline fraction.
Reference may be made to US Patent No.4665042, wherein a catalyst system
has been described which is suitable for the conversion of synthesis gas to
hydrocarbons, more particularly to a catalyst system comprising a coppercontaining
component together with an iron-containing component and a wax
cracking component such as a Zeolite. However a significant proportion of the
hydrocarbon product is in the form of methane rather than wax and this is a
disadvantage because the present need is wax, mainly.
Reference may be made to US Patent No.4086262, wherein a process is
disclosed for the conversion of synthesis gas using a single stage process
wherein the catalyst is a mixture of (i) a carbon monoxide reducing catalyst such
as a methanol catalyst or an iron-containing Fischer-Tropsch catalyst and (ii) a
ZSM-5 type Zeolite. However, the products described in this patent contain
significant amounts of gaseous hydrocarbons, particularly methane which in all
cases exceeds 10 percent by weight of the hydrocarbon product.
The main object of the present invention is to provide a process for the
preparation of a catalyst, useful for the production of hydrocarbons from
synthesis gas, which obviates the drawbacks of the hitherto known prior art as
detailed above.
Another object of the present invention is to provide a process for the preparation
of an improved iron catalyst using alternative naturally occurring siliceous
material, bentonite as support in place of silica and kieselghur to obtain wax from
the synthesis gas.
Yet another object of the present invention is to provide a process for the
preparation of a catalyst having high selectivity.
Still another object of the present invention is to provide a process for the
preparation of a catalyst of high yielding nature.
Still yet another object of the present invention is to provide a process which is
simple and environment friendly.
In the present invention there is provided a process for the preparation of a
catalyst, useful for the production of hydrocarbons from synthesis gas, which
involves heating at a temperature in the range of 70 to 85 degree Celsius, under
constant stirring, an aqueous solution of a mix of 86 to 96 wt % ferric nitrate, 1 to
10 wt % copper nitrate and 1 to 4 wt % manganese nitrate. Addition of preheated
sodium carbonate solution to the resulting mixture of aqueous solutions of
nitrates at a temperature in the range of 70 to 85 degree Celsius under constant
stirring till it becomes neutral. Continuing the addition of sodium carbonate and
simultaneously adding pre-heated bentonite slowly, under stirring, till the pH of
the solution reaches between 8 and 9. Continuing the stirring for a time period in
the range of 20 to 40 minutes after addition of sodium carbonate is stopped.
Filtering the precipitate and washing the same with warm water till the washings
are nitrate free. Addition of potassium hydroxide to the precipitate followed by
thorough kneading to ensure uniform distribution of the potassium salt. Drying
the resultant product at a temperature in the range of 70 to 90 degree Celsius for
a time period in the range of 10 to 16 hours in an air oven. Cooling the resultant
product to room temperature. Extruding to at least V4" size. Drying the extrudes at
105±5 degree Celsius for a time period in the range of 20 to 30 hours and sizing
to at least +6 to -14 mesh BSS.
Accordingly the present invention provides a process for the preparation of a
catalyst, useful for the production of hydrocarbons from synthesis gas which
comprises heating under constant stirring an aqueous solution of a mixture of
ferric nitrate in the range of 86 to 96 wt %, copper nitrate in the range of 1 to 10
wt % and manganese nitrate in the range of 1 to 4 wt %, at a temperature in the
range of 70 to 85 degree Celsius; adding pre-heated sodium carbonate solution
to the resulting mixture at a temperature in the range of 70 to 85 degree Celsius
under constant stirring till it becomes neutral; continuing the addition of sodium
carbonate solution and simultaneously adding pre-heated bentonite slowly, under
stirring, till the pH of the solution reaches between 8 and 9; continuing the stirring
for a time period in the range of 20 to 40 minutes after addition of sodium
carbonate is stopped; filtering the precipitate and washing the same with warm
water till the washings are nitrate free; adding potassium hydroxide to the
precipitate followed by thorough kneading to ensure uniform distribution of the
potassium salt; drying the resultant product at a temperature in the range of 70 to
90 degree Celsius for a time period in the range of 10 to 16 hours in an air oven;
cooling the resultant product to room temperature; extruding to at least %" size;
drying the extrudes at 105 ±5 degree Celsius for a time period in the range of 20
to 30 hours and sizing to at least +6 to -14 mesh BSS.
In an embodiment of the present invention, the aqueous solutions of the nitrates
are made with de-mineralised water.
In another embodiment of the present invention, the amount of de-mineralised
water used is in the range of 4 to 6 times of the total amount of nitrates (w/w).
In yet another embodiment of the present invention, the sodium carbonate*
solution used is of at least 3.5 molar.
In still another embodiment of the present invention, the bentonite is pre-heated
at a temperature in the range of 350 to 500 degree Celsius for a time period in
the range of 1 to 3 hours.
In still yet another embodiment of the present invention, brown ring test is
performed to check for the presence of nitrate in the washings.
The novelty of the present invention resides in providing a process for the
preparation of a catalyst, useful for the production of hydrocarbons from
synthesis gas, wherein the process is simple and environment friendly and the
catalyst obtained is of high yielding nature and has high selectivity.
The novelty of the present invention has been achieved by the non-obvious
inventive step wherein naturally occuring siliceous material, bentonite has been
incorporated as support in place of silica and kieselghur, in an environment
friendly manner unlike prior art processes
The non-obvious inventive process step of using naturally occurring siliceous
material, bentonite as support in place of silica and kieselghur, has made it
possible for the present invention to provide a novel simple and environment
friendly process for the preparation of an improved iron catalyst of high yielding
nature and having high selectivity to obtain wax from synthesis gas.
The details of the process steps of the present invention are:
1. Preparing an aqueous solution of a mix of 86 to 96 wt % ferric nitrate, 1 to
10 wt % copper nitrate and 1 to 4 wt % manganese nitrate in demineralised
water of amount which is 4 to 6 times of the total amount of
nitrates (w/w).
2. Heating the aqueous solution nitrates, obtained in step 1, under constant
stirring at a temperature in the range of 70 to 85 degree Celsius.
3. Adding pre-heated sodium carbonate solution, of at least 3.5 molar, to the
resulting mixture of heated aqueous solution of nitrates at a temperature in
the range of 70 to 85 degree Celsius under constant stirring till it becomes
neutral.
4. Continuing the addition of sodium carbonate and simultaneously adding
under stirring pre-heated bentonite slowly till the pH of the solution
reaches between 8 and 9. The bentonite is pre-heated to a temperature in
the range of 350 to 500 degree Celsius for a time period in the range of 1
to 3 hours.
5. After addition of sodium carbonate is stopped, the stirring is continued for
a time period in the range of 20 to 40 minutes.
6. Filtering the precipitate and washing the same with warm water having
temperature of around 50 degree Celsius till the washings are nitrate free.
Brown ring test is performed to check for the presence of nitrate in the
washings.
7. Adding potassium hydroxide to the precipitate followed by thorough
kneading to ensure uniform distribution of the potassium salt.
8. Drying the resultant product, obtained in step 7, at a temperature in the
range of 70 to 90 degree Celsius for a time period in the range of 10 to 16
hours in an air oven.
9. Cooling the resultant product to room temperature.
10. Extruding to at least 1/4" size.
11. Drying the extrudes at a temperature of 105+5 degree Celsius for a time
period in the range of 20 to 30 hours.
12. Sizing to at least +6 to -14 mesh BSS.
The following examples are given by way of illustration of the process in actual
practice and should not be construed to limit the scope of the present invention.
Example-1
750 grams of ferric nitrate, 79.1 grams of copper nitrate and 22 grams of
manganese nitrate were weighed separately and dissolved together in 4522 ml of
de-mineralised water. This nitrate solution was heated to 80 degree Celsius
under constant stirring. 1200 ml of 3.5 molar sodium carbonate solution was
heated to 80 degree Celsius separately and was added to the nitrate solution at
80 degree Celsius under constant stirring. When solution became neutral, 31.2
grams of bentonite, which was pre-heated earlier to 450 degree Celsius for 2
hours, was added slowly under stirring while the addition of sodium carbonate
continued till pH was in between 8 and 9.
At this stage, addition of sodium carbonate was stopped and stirring continued
for 30 minutes. The precipitate was filtered and washed with warm water ( 50
degree Celsius ) till it was nitrate free. The nitrate test was carried out by the
brown ring test.
To this nitrate free mass, 6 grams of potassium hydroxide was added and the
precipitate was kneaded thoroughly for uniform distribution of the potassium salt.
The final product was dried at 80 degree Celsius for 14 hours in an air oven. It
was cooled to room temperature and extruded to 1/4" size extrudates which were
further dried at 105 ± 5 degree Celsius for 26 hours. The extrudates were sized
to +6 to-14 mesh BSS.
Example-2
725 grams of ferric nitrate, 8.2 grams of copper nitrate and 23 grams of
manganese nitrate were weighed separately and dissolved together in 4522 ml of
de-mineralised water. This nitrate solution was heated to 85 degree Celsius
under constant stirring. 1200 ml of 3.5 molar sodium carbonate solution was
heated to 85 degree Celsius separately and was added to the nitrate solution at
85 degree Celsius under constant stirring. When solution became neutral, 31.2
grams of bentonite, which was preheated earlier to 450 degree Celsius for 2
hours, was added slowly under stirring while the addition of sodium carbonate
continued till pH was in between 8 and 9.
At this stage, addition of sodium carbonate was stopped and stirring continued
for 30 minutes. The precipitate was filtered and washed with warm water ( 50
degree Celsius ) till it was nitrate free. The nitrate test was carried out by the
brown ring test.
To this nitrate free mass, 6 grams of potassium hydroxide was added and the
precipitate was kneaded thoroughly for uniform distribution of the potassium salt.
The final product was dried at 85 degree Celsius for 14 hours in an air oven. It
was cooled to room temperature and extruded to 1/4" size extrudates which were
further dried at 105 ± 5 degree Celsius for 26 hours. The extrudates were siz.ed
to +6 to -14 mesh BSS.
Example-3
750 grams of ferric nitrate, 79.1 grams of copper nitrate and 22 grams of
manganese nitrate were weighed separately and dissolved together in 4522 ml of
de-mineralised water. This nitrate solution was heated to 75 degree Celsius
under constant stirring. 1200 ml of 3.5 molar sodium carbonate solution was
heated to 75 degree Celsius separately and was added to the nitrate solution at
75 degree Celsius under constant stirring. When solution became neutral, 31.2
grams of bentonite, which was preheated earlier to 450 degree Celsius for 2
hours, was added slowly under stirring while the addition of sodium carbonate
continued till pH was in between 8 & 9.
At this stage, addition of sodium carbonate was stopped and stirring continued
for 30 minutes. The precipitate was filtered and washed with warm water ( 50
degree Celsius ) till it was nitrate free. The nitrate test was carried out by the
brown ring test.
To this nitrate free mass, 5 grams of potassium hydroxide was added and the
precipitate was kneaded thoroughly for uniform distribution of the potassium salt.
The final product was dried at 75 degree Celsius for 14 hours in an air oven. It
was cooled to room temperature and extruded to 1/4" size extrudates which were
further dried at 105 ± 5 degree Celsius for 23 hours. The extrudates were sized
to =6 -14 mesh BSS.
The main advantages of the present invention are:
1. The process obviates the drawbacks of the hitherto known prior art as detailed
above.
2. The a process provides an improved iron catalyst using alternative naturally
occurring siliceous material, bentonite as support in place of silica and kieselghur
to obtain wax from synthesis gas.
3. The process provides a catalyst having high selectivity.
4. The process provides a catalyst of high yielding nature.
5. The process is simple and environment fondly.

We claim:
1. A process for the preparation of a catalyst, useful for the production of
hydrocarbons from synthesis gas which comprises heating under constant
stirring an aqueous solution of a mixture of ferric nitrate in 86 to 96
wt %, copper nitrate in the range of 1 to 10 wt % and manganese nitrate in the
range of 1 to 4 wt %, at a temperature in 70 to 85 degree Celsius;
adding pre-heated sodium carbonate solution to the resulting mixture at a
temperature in the range of 70 to 85 degree Celsius under constant stirring till it
becomes neutral; continuing the addition of sodium carbonate solution and
simultaneously adding pre-heated bentonite slowly, under stirring, till the pH of
the solution reaches between 8 and 9; continuing the stirring for a time period in
the range of 20 to 40 minutes after addition of sodium carbonate is stopped;
filtering the precipitate and washing the same with warm water till the washings
are nitrate free; adding potassium hydroxide to the precipitate followed by
thorough kneading to ensure uniform distribution of the potassium salt; drying the
resultant product at a temperature in the range of 70 to 90 degree Celsius for a
time period in the range of 10 to 16 hours in an air oven; cooling the resultant
product to room temperature; extruding to 1/4" size; drying the extrudes at
105 ±5 degree Celsius for a time period 20 to 30 hours and sizing
to at least +6 to -14 mesh BSS.
2 . A process as claimed in claiml-2, wherein the amount of de-mineralised water
used is 4 to 6 times of the total amount of nitrates (w/w).
3. A process as claimed in claim1-3, wherein the sodium carbonate solution used
is of 3.5 molar.
5. A process as claimed in claim1-4, wherein the bentonite is pre-heated at a
temperature in the range of 350 to 500 degree Celsius for a time period in the

range of 1 to 3 hours.
6. A process for the preparation of a catalyst, useful for production of
hydrocarbons from synthesis gas, substantially as herein described with reference to the examples.

Documents:

273-del-2003-abstract.pdf

273-del-2003-claims-(30-03-2009).pdf

273-del-2003-claims.pdf

273-del-2003-complete specification (granted).pdf

273-DEL-2003-Correspondence-Others-(20-11-2008).pdf

273-del-2003-correspondence-others.pdf

273-del-2003-correspondence-po.pdf

273-del-2003-description (complete).pdf

273-del-2003-form-1.pdf

273-del-2003-form-18.pdf

273-del-2003-form-2.pdf

273-del-2003-form-3.pdf

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Patent Number

233472

Indian Patent Application Number

273/DEL/2003

PG Journal Number

14/2009

Publication Date

27-Mar-2009

Grant Date

30-Mar-2009

Date of Filing

12-Mar-2003

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	PANDULA SAMUEL	CENTRAL FUEL RESEARCH INSTITUTE, P.O.F.R.I.-828108, DHANBAD, JHARKHAND, INDIA
2	YOGESH CHANDRA DASANDHI	CENTRAL FUEL RESEARCH INSTITUTE, P.O.F.R.I.-828108, DHANBAD, JHARKHAND, INDIA
3	SUDIP MAITY	CENTRAL FUEL RESEARCH INSTITUTE, P.O.F.R.I.-828108, DHANBAD, JHARKHAND, INDIA

PCT International Classification Number

B01J 21/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA