PREPARATION METHOD OF PLATINUM/TIN/METAL/ALUMINA CATALYST FOR DIRECT DEHYDROGENATION OF n-BUTANE AND METHOD FOR PRODUCING C4 OLEFINS USING SAID CATALYST
The provided is a method for preparing a platinum-tin-metal-alumina catalyst by comprising: as an active ingredient, platinum which has a high activity in a direct dehydrogenation reaction of n-butane, tin which can increase the catalyst stability by preventing carbon deposition; additionally metal for reducing the level of catalyst inactivation over the reaction time; and an alumina carrier for supporting said components. Further, provided is a method for producing a high value product, C4 olefins from low cost n-butane by using the catalyst prepared by the method according to the present invention in a direct dehydrogenation reaction.
1 . A method for preparing a platinum-tin-metal-alumina catalyst for a direct dehydrogenation reaction of n-butane comprising the following steps:
(a) preparing a solution of a metal precursor by dissolving a metal precursor into a first solvent;
(b) impregnating the metal precursor solution to an alumina carrier;
(c) thermally drying and heat-treating the product obtained from the above step (b) so as to obtain a metal-alumina wherein metal is supported to an alumina carrier;
(d) preparing a tin precursor solution by dissolving a tin precursor and an acid into a second solvent to form a tin precursor solution;
(e) impregnating the above-prepared tin precursor solution from the step (d) to the metal-alumina prepared by the above step (c);
(f) thermally drying and heat-treating the product obtained from the above step (e) to obtain a tin-metal-alumina;
(g) preparing a platinum precursor solution by dissolving a platinum precursor into a third solvent;
(h) impregnating the above-prepared platinum precursor solution from the step (g) to the tin-metal-alumina prepared from the above step (f); and
(i) thermally drying and heat-treating the product obtained from the above step (h) so as to obtain a platinum-tin-metal-alumina catalyst for a direct dehydrogenation reaction of n-butane.
2 . The method according to claim 1 , wherein the metal used in step (a) is at least one selected from transition metals and alkali metals.
3 . The method according to claim 1 , wherein the metal used in step (a) is at least one selected from zinc, gallium, indium, lanthanum, cerium, lithium, sodium, potassium and rubidium.
4 . The method according to claim 1 , wherein the metal precursor used in the above step (a) is at least one selected from metal chloride, nitrate, bromide, oxide, hydroxide or acetate precursor.
5 . The method according to claim 1 , wherein the metal content of the step (a) is 0.2-5 wt %, based on the total weight of the finally obtained platinum-tin-metal-alumina catalyst.
6 . The method according to claim 1 , wherein each first, second and third solvent used in the above step (a), (d) and (g), respectively is water or an alcohol.
7 . The method according to claim 1 , wherein, in the step (c), the thermal drying is carried out at a temperature range of 50-200° C., and the heat treatment is carried out at a temperature range of 350-1000° C.
8 . The method according to claim 1 , wherein, in the step (f) and (i), the thermal drying is carried out at a temperature range of 50-200° C., and the heat treatment is carried out at a temperature range of 400-800° C.
9 . A method for producing C4 olefins by conducting a direct dehydrogenation reaction of n-butane by using a mixed gas comprising n-butane and nitrogen as reactants on a platinum-tin-metal-alumina catalyst prepared by the method according to claim 1 .
10 . The method for producing C4 olefins according to claim 9 , wherein the direct dehydrogenation reaction of n-butane is carried out at a temperature range of 300-800° C.
11 . The method for producing C4 olefins according to claim 9 , wherein n-butane:nitrogen ratio by volume in the mixed gas is 1:0.2-10.
12 . The method for producing C4 olefins according to claim 9 , wherein the feeding amount of the mixed gas is a space velocity of 10-6000 cc·hr −1 ·gcat −1 based on n-butane.
13 . A method for producing C4 olefins by conducting a direct dehydrogenation reaction of n-butane by using a mixed gas comprising n-butane and nitrogen as reactants on a platinum-tin-metal-alumina catalyst prepared by the method according claim 2 .
14 . A method for producing C4 olefins by conducting a direct dehydrogenation reaction of n-butane by using a mixed gas comprising n-butane and nitrogen as reactants on a platinum-tin-metal-alumina catalyst prepared by the method according claim 3 .
15 . A method for producing C4 olefins by conducting a direct dehydrogenation reaction of n-butane by using a mixed gas comprising n-butane and nitrogen as reactants on a platinum-tin-metal-alumina catalyst prepared by the method according claim 4 .
16 . A method for producing C4 olefins by conducting a direct dehydrogenation reaction of n-butane by using a mixed gas comprising n-butane and nitrogen as reactants on a platinum-tin-metal-alumina catalyst prepared by the method according claim 5 .
17 . A method for producing C4 olefins by conducting a direct dehydrogenation reaction of n-butane by using a mixed gas comprising n-butane and nitrogen as reactants on a platinum-tin-metal-alumina catalyst prepared by the method according claim 6 .
18 . A method for producing C4 olefins by conducting a direct dehydrogenation reaction of n-butane by using a mixed gas comprising n-butane and nitrogen as reactants on a platinum-tin-metal-alumina catalyst prepared by the method according claim 7 .
19 . A method for producing C4 olefins by conducting a direct dehydrogenation reaction of n-butane by using a mixed gas.