Catalytic cracking gasoline prehydrogenation method

Abstract

A catalytic cracking gasoline prehydrogenation method is provided. Thiol etherification and double bond isomerization reactions are carried out on catalytic cracking gasoline through a prehydrogenation reactor. The reaction conditions are as follows: the reaction temperature is between 80° C. and 160° C., the reaction pressure is between 1 MPa and 5 MPa, the liquid-volume hourly space velocity is from 1 to 10 h.sup.−1, and the hydrogen-oil volume ratio is (3-8):1; a prehydrogenation catalyst comprises a carrier and active ingredients, the carrier contains an aluminium oxide composite carrier with a macroporous structure and one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-35, mordenite, amorphous form aluminum silicon, SAPO-11, MCM-22, a Y molecular sieve and a beta molecular sieve, the surface of the carrier is loaded with one or more of the active ingredients cobalt, molybdenum, nickel and tungsten; based on oxides, the content of the active ingredients is between 0.1% and 15.5%.

Claims

1. A catalytic cracking gasoline prehydrogenation method, comprising: pumping catalytic cracking gasoline into a prehydrogenation reactor; and carrying out thiol etherification and double bond isomerization reactions on the catalytic cracking gasoline with a prehydrogenation catalyst through the prehydrogenation reactor, wherein the reaction conditions are as follows: the reaction temperature is between 80° C. and 160° C., the reaction pressure is between 1 MPa and 5 MPa, the liquid-volume hourly space velocity is from 1 to 10 h.sup.−1, and the hydrogen-oil volume ratio is (3-8):1; the prehydrogenation catalyst comprises a carrier and active ingredients, the carrier contains an aluminium oxide composite carrier with a macroporous structure and one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-35, mordenite, amorphous form aluminum silicon, SAPO-11, MCM-22, a Y molecular sieve and a beta molecular sieve; the alumina composite carrier contains 0.1-12 wt % of tungsten-doped lanthanum ferrite, the mesopores of the alumina composite carrier account for 1-85 % of the total pores, and the macropores of the alumina composite carrier account for 1-70 % of the total pores; the surface of the carrier loads one or more of the active ingredients comprising cobalt, molybdenum, nickel, and tungsten, and based on oxides, the content of the active ingredients is between 0.1% and 15.5%; the tungsten-doped lanthanum ferrite is tungsten-doped lanthanum ferrite with micro-mesopores and the preparation method of the tungsten-doped lanthanum ferrite with micro-mesopores comprises: dissolving citric acid in water and stirring; next, adding lanthanum nitrate and ferric nitrate to the citric acid solution at stirring conditions; adding sodium polyacrylate or polyacrylic acid in an amount which is 0.1-9 wt % of the tungsten-doped lanthanum ferrite, and then adding a tungsten-containing compound, based on oxides, the tungsten content accounts for 0.1-8 wt % of the tungsten-doped lanthanum ferrite; stirring and reacting; and drying, calcining and grinding the resulting material, thus obtaining a finished product.

2. The catalytic cracking gasoline prehydrogenation method according to claim 1, wherein the reaction conditions are as follows: the reaction temperature is between 90° C. and 145° C., the reaction pressure is between 1 MPa and 4 MPa, the liquid-volume hourly space velocity is from 1 to 8 .sup.−1, and the hydrogen-oil volume ratio is (3-6):1.

3. The catalytic cracking gasoline prehydrogenation method according to claim 2, wherein the aluminium oxide composite carrier contains 0.1-12 wt % of silicon oxide and 0.1-10 wt % of tungsten-doped lanthanum ferrite; mesopores account for 1-80% of the total pores, macropores account for 1-40% of the total pores, and the micropores, mesopores, and macropores in the carrier are unevenly distributed.

4. The catalytic cracking gasoline prehydrogenation method according to claim 2, wherein the preparation method of the alumina composite carrier comprises: adding an aluminum source and sesbania powder to a kneader and mixing; adding an inorganic acid solution and an organic polymer and kneading; and then adding tungsten-doped lanthanum ferrite and kneading; and carrying out extruding, molding, drying and calcination, thus obtaining the alumina composite carrier.

5. The catalytic cracking gasoline prehydrogenation method according to claim 2, wherein the preparation method of the prehydrogenation catalyst comprises: preparing an impregnation solution with active ingredient materials containing cobalt, molybdenum, nickel and tungsten, impregnating the carrier in the impregnation solution, drying at 120-180° C. for 4-8 h, and calcining at 450-800° C. for 3-9 h, thus obtaining a prehydrogenation catalyst.

6. The catalytic cracking gasoline prehydrogenation method according to claim 1, wherein the tungsten-doped lanthanum ferrite in the alumina composite carrier accounts for 0.3-9 wt %, and in the tungsten-doped lanthanum ferrite, tungsten accounts for 0.1-8 wt %.

7. The catalytic cracking gasoline prehydrogenation method according to claim 6, wherein the preparation method of the prehydrogenation catalyst comprises: preparing an impregnation solution with active ingredient materials containing cobalt, molybdenum, nickel and tungsten, impregnating the carrier in the impregnation solution, drying at 120-180° C. for 4-8 h, and calcining at 450-800° C. for 3-9 h, thus obtaining a prehydrogenation catalyst.

8. The catalytic cracking gasoline prehydrogenation method according to claim 1, wherein in the aluminium oxide composite carrier with a macroporous structure, mesopores account for 5-70% of the total pores, and macropores account for 5-45% of the total pores.

9. The catalytic cracking gasoline prehydrogenation method according to claim 1, wherein the aluminium oxide composite carrier contains 0.1-12 wt % of silicon oxide and 0.1-10 wt % of tungsten-doped lanthanum ferrite; mesopores account for 1-80% of the total pores, macropores account for 1-40% of the total pores, the micropores, mesopores, and macropores in the carrier are unevenly distributed.

10. The catalytic cracking gasoline prehydrogenation method according to claim 9, wherein the preparation method of the alumina composite carrier comprises: adding an aluminum source and sesbania powder to a kneader and mixing; adding an inorganic acid or organic acid solution and an organic polymer and kneading; and then adding tungsten-doped lanthanum ferrite and mixing, thus obtaining an alumina precursor for later use; adding a silicon source to an acid solution of an organic polymer and mixing, and then mixing the resulting solution with the alumina precursor, wherein the unit content of the organic polymer in the alumina precursor is 1.5 times higher than the content of the organic polymer in the silicon source; and carrying out extruding, molding, drying and calcination, thus obtaining the alumina carrier.

11. The catalytic cracking gasoline prehydrogenation method according to claim 10, wherein the silicon source is one or two of diatomite and opal, and the aluminum source is one or more of kaolin, rectorite, perlite, and montmorillonite.

12. The catalytic cracking gasoline prehydrogenation method according to claim 1, wherein the preparation method of the alumina composite carrier comprises: adding an aluminum source and sesbania powder to a kneader and mixing; adding an inorganic acid solution and an organic polymer and kneading; and then adding tungsten-doped lanthanum ferrite and kneading; and carrying out extruding, molding, drying and calcination, thus obtaining the alumina composite carrier.

13. The catalytic cracking gasoline prehydrogenation method according to claim 12, wherein the organic polymer is one or more of polyvinyl alcohol, sodium polyacrylate, polyethylene glycol, and polyacrylate.

14. The catalytic cracking gasoline prehydrogenation method according to claim 1, wherein the preparation method of the prehydrogenation catalyst comprises: preparing an impregnation solution with active ingredient materials containing cobalt, molybdenum, nickel and tungsten, impregnating the carrier in the impregnation solution, drying at 120-180° C. for 4-8 h, and calcining at 450-800° C. for 3-9 h, thus obtaining a prehydrogenation catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The invention is described in further detail below through examples, but these examples should not be considered as limiting the invention. The raw material reagents used in the invention are all commercially available products.

(2) Example 1

(3) 1. Preparation of Tungsten-Doped Lanthanum Ferrite with Micro-Mesopores

(4) 2.2 mol of La (NO.sub.3).sub.3 was dissolved in 100 mL of water in a stirring way, and citric acid was added and stirred to be dissolved; 4.2 mol of Fe(NO.sub.3).sub.3, 160 g of sodium polyacrylate, and an aqueous solution containing 10 g of ammonium metatungstate were added in sequence and the resulting solution was further stirred for 30 min; the resulting solution was subjected to drying, calcination and grinding, thus obtaining micro-mesoporous tungsten-doped lanthanum ferrite.

(5) 2. Preparation of Alumina Carrier

(6) 2.2 g of micro-mesoporous tungsten-doped lanthanum ferrite was added with citric acid for later use, 300 g of pseudo-boehmite powder and 20.0 g of sesame powder were added to a kneader and well mixed, and then nitric acid and 8 g of sodium polyacrylate were added and the resulting material was kneaded well; the micro-mesoporous tungsten-doped lanthanum ferrite was then added and well mixed; the resulting material was kneaded and extruded into a clover shape. The resulting material was dried at 120° C. for 8 h and calcined at 700° C. for 4 h, thus obtaining an alumina carrier 1 containing the micro-mesoporous tungsten-doped lanthanum ferrite. The pore structure of the carrier is shown in Table 1.

(7) 3. Preparation of Catalyst

(8) The alumina carrier 1 was kneaded and stirred together with sesame powder, acidified amorphous silicon-alumina, and deionized water, the resulting material was dried and calcined, thus obtaining a composite carrier 1-1; ammonium heptamolybdate and nickel nitrate were added to distilled water to prepare an impregnation solution to impregnate the composite carrier 1-1; the resulting catalyst precursor was dried at 140° C. and then calcined at 500° C. for 6 h, thus obtaining catalyst 1. The catalyst 1 mainly comprises: 73.2 wt % of the alumina carrier containing micro-mesoporous tungsten-doped lanthanum ferrite, 4.8 wt % of alumina, 5.2 wt % of silicon oxide, 7.7 wt % of nickel oxide, and 9.1 wt % of molybdenum oxide.

(9) Example 2

(10) 1. Preparation of Tungsten-Doped Lanthanum Ferrite

(11) 2.2 mol of La (NO.sub.3).sub.3 was dissolved in 100 mL of water in a stirring way, and citric acid was added and stirred to be dissolved; 4.2 mol of Fe(NO.sub.3).sub.3 and an aqueous solution containing 10 g of ammonium metatungstate were added in sequence and the resulting solution was further stirred for 30 min; the resulting solution was subjected to drying, calcination and grinding, thus obtaining tungsten-doped lanthanum ferrite.

(12) 2. Preparation of Alumina Carrier

(13) 2.2 g of tungsten-doped lanthanum ferrite was added with citric acid, 300 g of pseudo-boehmite powder and 20.0 g of sesame powder were added to a kneader and well mixed, and then nitric acid and 8 g of sodium polyacrylate were added and the resulting material was kneaded well; the micro-mesoporous tungsten-doped lanthanum ferrite was then added and well mixed; the resulting material was kneaded and extruded into a clover shape. The resulting material was dried at 120° C. for 8 h and calcined at 700° C. for 4 h, thus obtaining an alumina carrier 2 containing the tungsten-doped lanthanum ferrite. The pore structure of the carrier is shown in Table 1.

(14) 3. Preparation of Catalyst

(15) As in Example 1, zsm-5 was introduced into the carrier to obtain the composite carrier 2-1; the composite carrier 2-1 was impregnated in an impregnating solution containing molybdenum and cobalt, and the obtained catalyst precursor was dried at 140° C. and calcined at 530° C. for 5 h to obtain catalyst 2. The catalyst 2 mainly comprised: 71.5 wt % of the alumina carrier containing tungsten-doped lanthanum ferrite, 7 wt % of zsm-5, 10.8 wt % of molybdenum oxide, and 10.7 wt % of cobalt oxide.

(16) Example 3

(17) The preparation of the carrier was same as that in Example 1, except that the micro-mesoporous tungsten-doped lanthanum ferrite accounted for 6 wt % of the carrier. The preparation of the catalyst was the same as that in Example 1, and activated montmorillonite was used as the aluminum source. The difference lied in that the active ingredients were molybdenum and tungsten and the catalyst 3 mainly comprised: 75.6 wt % of the alumina carrier containing micro-mesoporous tungsten-doped lanthanum ferrite, 4.0 wt % of alumina, 4.0 wt % of silicon oxide, 10.1 wt % of molybdenum oxide, and 9.1 wt % of tungsten oxide.

(18) Example 4

(19) Preparation of Modified Alumina Carrier

(20) 2 g of sodium polyacrylate was dissolved in nitric acid, and 28 g of fine silicon powder was added and stirred well to obtain a fine silicon powder-sodium polyacrylate mixture; 1/10 of the resulting mixture was taken for later use, and citric acid was added to 2.0 g of the micro-mesoporous tungsten-doped lanthanum ferrite and the resulting material was set aside for later use. 310 G of pseudo-boehmite powder and 22.0 g of sesame powder were added into the kneader, nitric acid and 28 g of a nitric acid solution of sodium polyacrylate were then added in sequence and well mixed, the above-mentioned fine silicon powder-sodium polyacrylate mixture was added and knead well; and then the micro-mesoporous tungsten-doped lanthanum ferrite was added and well mixed; and the resulting material was kneaded and extruded into a clover shape. The resulting material was dried at 130° C. for 7 h and calcined at 650° C. for 5 h, thus obtaining an alumina carrier 4 containing the micro-mesoporous tungsten-doped lanthanum ferrite and silicon oxide.

(21) The preparation of the catalyst was the same as that in Example 2, except that the active ingredients were tungsten, nickel, and molybdenum, and the catalyst 4 mainly comprised: 71.7 wt % of the alumina carrier containing micro-mesoporous tungsten-doped lanthanum ferrite, 5 wt % of zsm-5, 7.8 wt % of tungsten oxide, 3.2 wt % of nickel oxide, and 12.3 wt % of molybdenum oxide.

(22) Example 5

(23) 2.0 mol of La (NO.sub.3).sub.3 was dissolved in 100 mL of water in a stirring way, and citric acid was added and stirred to be dissolved; 4.0 mol of Fe(NO.sub.3).sub.3, 160 g of sodium polyacrylate, and an aqueous solution containing 12 g of ammonium metatungstate were added in sequence and the resulting solution was further stirred for 30 min; the resulting solution was subjected to drying, calcination and grinding, thus obtaining micro-mesoporous tungsten-doped lanthanum ferrite.

(24) The preparation of the carrier was the same as that in Example 4, except that the tungsten-doped lanthanum ferrite accounted for 3 wt % of the carrier, and activated diatomite and kaolin were used as a silicon source and an aluminum source. The catalyst 5 mainly comprised: 74.0 wt % of the alumina carrier containing tungsten-doped lanthanum ferrite and silicon oxide, 4 wt % of zsm-5, 12.9 wt % of molybdenum oxide, and 9.1 wt % of tungsten oxide.

(25) Example 6

(26) The preparation of the catalyst was the same as that in Example 4, except that mordenite was added to the catalyst, and the catalyst 6 mainly comprised: 80.1 wt % of the alumina carrier 4 containing micro-mesoporous tungsten-doped lanthanum ferrite and silicon oxide, 6.8 wt % of mordenite, 10.4 wt % of molybdenum oxide, and 2.7 wt % of tungsten oxide. Activated diatomite and kaolin were used as a silicon source and an aluminum source.

(27) Example 7

(28) The preparation of the catalyst was the same as that in Example 6, except that beta molecular sieve was added to the catalyst, and the catalyst 7 mainly comprised: 72.8 wt % of the alumina carrier 4 containing micro-mesoporous tungsten-doped lanthanum ferrite and silicon oxide, 6.7 wt % of the beta molecular sieve, 10.4 wt % of molybdenum oxide, and 10.1 wt % of nickel oxide. Activated diatomite and kaolin were used as a silicon source and an aluminum source.

(29) Comparative Example 1

(30) The preparation of the carrier was the same as that in Example 4, except that lanthanum ferrite was added. The preparation of the catalyst was the same as that in Example 4, and the reaction conditions were the same as those in Example 4. The reaction results are shown in Table 2.

(31) TABLE-US-00001 TABLE 1 The specific surface area and pore size distribution of the macroporous alumina carrier Specific Total pore Macropore Macropore Mesopore surface area volume size size size m.sup.2/g ml/g ml/g nm nm 1 264.2 1.57 0.75 121 31 2 257.7 1.66 0.87 96 40 3 268.2 1.51 0.56 103 21 4 262.4 1.81 0.60 147 34 5 265.3 1.75 0.45 132 26

(32) TABLE-US-00002 TABLE 2 Catalyst prehydrogenation results Mercaptan Internal Diolefin Gasoline removal olefin Octane removal yield Catalyst rate % increase % loss rate % wt % Example 1 93.6 0.23 0.3 100 98.4 Example 2 96.8 0.40 0.4 100 98.3 Example 3 94.6 0.32 0.2 100 98.6 Example 4 98.4 0.38 0.2 100 99.4 Example 5 97.7 0.52 0.3 100 99.1 Example 6 97.9 0.44 0.2 100 99.2 Example 7 98.9 0.50 0.2 100 99.3 Comparative 89.7 0.6 87.2 95.8 Example 1

(33) FCC gasoline was hydrogenated through a prehydrogenation reactor in the presence of the prehydrogenation catalysts 1, 3, 4, 7 to remove diolefins, mercaptans, and sulfides, and also realize double bond isomerization (i.e., conversion of terminal olefins into internal olefins), and saturate the remaining diolefins. The reaction temperature was 115° C., the reaction pressure was 1.8 MPa, the liquid-volume hourly space velocity was 5 h.sup.−1, and the hydrogen-oil volume ratio was 4:1. The reaction results are shown in Table 2.

(34) During the prehydrogenation catalysts 2, 5, and 6, the reaction temperature was 108° C., wherein the reaction pressure was 1.4 MPa, the liquid-volume hourly space velocity was 4 h.sup.−1, and the hydrogen-oil volume ratio was 3:1. The reaction results are shown in Table 2.

(35) The prehydrogenation catalysts 1-7 has the advantages of low octane loss, high gasoline yield, high mercaptan removal rate, and good activity. The catalysts can effectively inhibit side reactions such as olefin polymerization and excessive cracking, inhibit the cracking reaction of low-carbon hydrocarbons, ensure a high gasoline yield, which is conducive to the long-term operation of the device; the surface of the catalyst carrier produces more active site load centers, which effectively improves the activity of the catalysts in removing diolefins, mercaptans, sulfides, and double bond isomerization. The catalysts have good activity and selectivity. After 600 hours of the reaction, for the products of the prehydrogenation catalysts 4 and 7, the mercaptan removal rates were 98.2% and 98.6%, respectively; the octane losses were 0.2 unit and 0.3 unit, respectively; the carbon deposition rates were 0.3 and 0.2, respectively; the liquid yields were 99.6% and 99.0% respectively; the internal olefin increases were 0.37% and 0.42%, respectively; the diolefin removal rates were 100% and 100%, respectively; and the reaction performance of the catalysts was stable.

(36) Certainly, the invention can also have various other embodiments. Without departing from the spirit and essence of the invention, those skilled in the art can make various corresponding changes and modifications according to the invention, but these corresponding changes and deformation should belong to the protection scope of the invention.