METHOD FOR DIRECT PRODUCTION OF GASOLINE-RANGE HYDROCARBONS FROM CARBON DIOXIDE HYDROGENATION

Abstract

A method for carbon dioxide direct hydrogenation to gasoline-range hydrocarbons is provided in this invention. Under the reaction conditions of 250-450 C., 0.01-10.0 MPa, 500-50000 mL/(h.Math.g.sub.cat) of feedstocks, 0.5-8 molar ratio of H.sub.2 to CO.sub.2, the mixture of carbon dioxide and hydrogen may be directly converted to gasoline-range hydrocarbons over a multifunctional hybrid catalyst. The multifunctional hybrid catalyst comprises: iron-based catalyst for carbon dioxide hydrogenation as the first component, one, two or more of zeolites optionally modified by metal as the second component. In this method, a per-pass conversion of CO.sub.2 may achieve more than 33%, the methane selectivity in the hydrocarbon products is less than 8%, the selectivity of gasoline-range hydrocarbons with carbon numbers from 5 to 11 in the hydrocarbon products is more than 70%. The obtained gasoline-range hydrocarbons exhibit high octane number due to its composition comprising isoparaffins and aromatics as the major components.

Claims

1. A method for direct production of gasoline-range hydrocarbons via carbon dioxide hydrogenation comprising: converting a gas stream comprising carbon dioxide and hydrogen to gasoline-range hydrocarbons in the presence of a multifunctional catalyst, wherein the multifunctional catalyst comprises an iron-based catalyst for carbon dioxide hydrogenation as a first component and at least one or two kinds of zeolites optionally modified with a metal as a second component, and the mass ratio of the first component to the second component is 1:10 to 10:1.

2. The method according to claim 1, wherein the converting is conducted under the following conditions: a temperature of 250-450 C., a pressure of 0.01-10.0 MPa, a gas hour space velocity of the gas stream being 500-50000 ml/((h.Math.g.sub.cat), and a molar ratio of hydrogen to carbon dioxide in the gas stream being 0.5-8.0.

3. The method according to claim 1, wherein the iron-based catalyst for carbon dioxide hydrogenation comprises Fe.sub.3O.sub.4 as a main active component, and optionally, no more than 30% by weight, an oxide promoter selected from the group consisting of sodium oxide, potassium oxide, manganese oxides, copper oxide, zirconium oxide, vanadium oxides, zinc oxide, cerium oxide, and combinations thereof.

4. The method according to claim 1, wherein the zeolites are selected from the group consisting of ZSM-5, ZSM-22, ZSM-23, Y, Beta, MOR, MCM-22, and combinations thereof, and the metal is selected from the group consisting of Mo, Zn, Rh, Ru, Ga, Cr, Co, Ni, Na, Cu, Pd, Pt, La, and combinations thereof in the amount of 0.1%-20%.

5. The method according to claim 1 comprising: making the iron-based catalyst components for CO.sub.2 hydrogenation by one of the following three preparation methods: A. one-pot synthesis method, comprising the following steps: (1) according to the catalyst composition, a soluble Fe(II) salt and a soluble Fe(III) salt are mixed and dissolved to form a salt solution-I; or the soluble Fe(II) salt, the Fe(III) salt, and a soluble promoter salt are mixed and dissolved to form a salt solution-II; wherein in the salt solution-I or salt solution-II, the concentration of Fe(III) is 0.05-1 mol/L, then a HCl solution with 5-12.1 mol/L HCl concentration is added into the salt solution-I or solution-II to adjust the pH value to 0-3, the molar ratio of Fe(III) to Fe(II) in the salt solutions-I and II is 2:(13); the soluble Fe(II) salt and Fe(II) salt are salt compounds that is dissolvable in water; the soluble promoter salt is a salt compound that is dissolvable in water; (2) an alkali solution is added dropwise into the salt solution I or salt solution II obtained from step (1) for titration to adjust the pH from 0-3 to 9-12; after finishing the titration, the solution is aged for 1-5 hours; wherein the alkali solution is an alkaline solution that is capable of adjusting the pH value of the salt solution I or salt solution II; the concentration of the alkali solution is 0.1-10 mol/L; in RCOOK and RCOONa, R is an organic group selected from the group consisting of C.sub.1-C.sub.20 alkyl group, C.sub.1-C.sub.20 alkenyl group and C.sub.6-C.sub.20 aryl group; (3) separating precipitates from the solution obtained in step (2) by magnetic adsorption, centrifugation or suction filtration, and then fully washing the precipitates with distilled water, drying, and optionally calcining at 200-600 C. for 2-10 hours to obtain the iron-based catalyst; B. one-pot synthesis method, comprising the following steps: (1) according to the catalyst composition, a soluble Fe(II) salt and a soluble Fe(III) salt are mixed and dissolved to form a salt solution, wherein in the salt solution, the concentration of Fe(III) is 0.05-1 mol/L, a HCl solution with 5-12.1 mol/L HCl concentration is added into the salt solution to adjust the pH value to 0-3; the molar ratio of Fe(III) to Fe(II) in the salt solution is 2:(13); (2) the alkali solution described in method A is added dropwise into the salt solution obtained from step (1) for titration to adjust pH value of the salt solution from 0-3 to 9-12; then the titrated solution is aged for 1-5 hours; (3) after reaction in (2), precipitates are separated from the solution obtained in (2) by magnetic adsorption, centrifugation or suction filtration, and then fully washed with distilled water, which is capable of controlling the content of residue Na or K by controlling the times and water usage of washing; and then the washed precipitates are dried, optionally calcined at 200-600 C. for 2-10 hours to obtain the iron-based catalyst with promoter Na or K; C. first synthesis of Fe.sub.3O.sub.4 by coprecipitation, and then addition of promoter by impregnation: (1) according to the catalyst composition, a soluble Fe(II) salt and a Fe(III) salt are mixed and dissolved to form a salt solution, wherein in the salt solution, the concentration of Fe(III) is 0.05-1 mol/L, a HCl solution with 5-12.1 mol/L HCl concentration is added into the salt solution to adjust the pH value to 0-3; the molar ratio of Fe(III) to Fe(II) in the salt solution is 2:(13); (2) the alkali solution described in method A is added dropwise into the salt solution obtained from step (1) for titration to adjust pH value of the salt solution from 0-3 to 9-12; after finishing the titration, the salt solution is aged for 1-5 hours; (3) after reaction in (2), precipitates are separated from the salt solutions by magnetic adsorption, centrifugation or suction filtration, and fully washed with distilled water, dried to form active composition Fe.sub.3O.sub.4; (4) catalyst synthesis from combination of active composition Fe.sub.3O.sub.4 and promoter salt by impregnation via a procedure as described below: according to the needed promoter content, the mass of promoter salt is calculated, and then the solution of a promoter salt is prepared, and Fe.sub.3O.sub.4 as prepared is impregnated with the promoter salt solution by equivalent-volume impregnation, after stirring, stewing, drying, calcination at 200-600 C. for 2-10 h, the iron-based catalyst with the promoter is obtained.

6. The method according to claim 1, wherein the zeolite modification is carried out according to one of the following methods for supporting the metal component: (1) equivalent-volume impregnation method: according to the needed metal content, the theoretical mass of metal salt is calculated, and then the solution of metal salt is prepared; the metal salt is one, two or more of the following salts: nitrate, chloride, bromide, acetate, acetylacetonate, citrate, oxalate; the zeolite to be modified is impregnated with the as-prepared salt solution by equivalent-volume impregnation, after stirring, stewing, drying, calcination at 300-700 C. for 2-10 h, the modified zeolite is obtained; (2) ion-exchanged method: according to the needed metal content, the theoretical mass of metal salt is calculated, and then the solution of metal salt is prepared; the metal salt is one, two or more of the following salts: nitrate, chloride, bromide, acetate, acetylacetonate, citrate, oxalate; the zeolite to be modified is mixed with the as-prepared metal salt solution at 1:(10-200) of mass ratio of solid to solution, and ion-exchanged for 2-24 h, after water washing, drying, calcination at 300-700 C. for 2-10 h, the metal-modified zeolite is obtained.

7. The method according to claim 1, wherein the two components of multifunctional catalysts are mixed according to any one of the following three methods: (1) powder mixing method: powders of iron-based catalyst and zeolite are grounded and mixed at the required mass ratio of iron-catalyst to zeolite, pelleted, crushed, and sieved to form the multifunctional catalyst; (2) granule mixing method: iron-based catalyst powders and zeolite powders are pelleted, crushed, and sieved, respectively; sieved granules of iron-based catalysts and zeolites are mixed homogeneously at the required mass ratio of iron-catalyst to zeolite to form the multifunctional catalyst; (3) multilayer catalyst packing method: catalyst is packed into a reactor according to the sequences of iron-based catalyst layer, and zeolite layer, among which iron-based catalyst layer is near to the feedstock inlet and zeolite layer is far to the feedstock inlet; between iron-based catalyst layer and zeolite layer, there is an optional isolated layer composed of inert materials, the mass ratio of the isolated layer to multifunctional catalyst is 0.01-10.

8. The method according to claim 1, wherein the gas stream comprises a gas containing carbon dioxide that is selected from the group consisting of industrial waste gas, automobile exhaust, coal combustion exhaust, carbon dioxide in atmosphere or seawater, and combinations thereof.

9. The method according to claim 1 wherein the mass ratio of the first component to the second component is 1:3 to 3:1.

10. The method according to claim 3 wherein the iron-based catalyst comprises 0.5-10% by weight of the oxide promoter.

11. The method according to claim 4 wherein the zeolites are one or more of ZSM-5 with 20-350 molar ratio of SiO.sub.2 to Al.sub.2O.sub.3, and MCM-22 with 20-200 molar ratio of SiO.sub.2 to Al.sub.2O.sub.3.

12. The method according to claim 4 wherein the zeolites comprise 0.5%-10% by weight of the metal.

13. The method according to claim 5 wherein the soluble Fe(II) salt and Fe(II) salt compounds are selected from the group consisting of chlorides, nitrates, acetates, and combinations thereof.

14. The method according to claim 5 wherein the soluble promoter salt is a salt selected from the group consisting of chlorides, nitrates, acetates, and combinations thereof.

15. The method according to claim 5 wherein the alkali solution is selected from the solutions of NaOH, KOH, Na.sub.2CO.sub.3, NaHCO.sub.3, K.sub.2CO.sub.3, KHCO.sub.3, Na.sub.2C.sub.2O.sub.4, K.sub.2C.sub.2O.sub.4, RCOONa, RCOOK, NH.sub.3.H.sub.2O, and combinations thereof.

16. The method according to claim 5 wherein in RCOOK and RCOONa, R is a methyl, ethyl, or phenyl group.

17. The method according to claim 7, wherein the two components of multifunctional catalysts are mixed by granule mixing or multilayer catalyst packing.

Description

DESCRIPTION OF PREFERRED EMBODIMENTS

[0038] Technique details of this invention could be largely described by the following examples. It should be noted that the following examples are provided to illustrate, but not to limit this invention.

Example 1

[0039] 31.62 g FeCl.sub.3.6H.sub.2O and 12.54 g FeCl.sub.2.4H.sub.2O were mixed and dissolved into 150 mL H.sub.2O to form iron salt solution, and then 5.1 mL of hydrochloric acid with 12.1 mol/L of HCl concentration were added into the said iron salt solution. After this, about 360 mL of 1.5 mol/L NaOH solution was added at a constant speed into the iron salt solution at stirring and 60 C., pH value of solution will be adjusted to 10.0 in about 1.5 h. After titration, the solution was continually stirring for 1 hour at 60 C., and then cooled to room temperature. After reaction, the precipitates were separated from the solution by magnetic adsorption, and washed once with 800 mL deioned water, and dried at 60 C. to obtained Na/Fe.sub.3O.sub.4 catalyst, which was further ground, pelleted, and sieved for use.

[0040] Zeolite pretreatment: zeolites were calcined at 500 C. for 4 hours, and then ground, pelleted and sieved for use. Here, zeolites includes zeolites from zeolite company of Nankai University, e.g. HY (SiO.sub.2/Al.sub.2O.sub.3=5), HMCM-22 (SiO.sub.2/Al.sub.2O.sub.3=30, HZSM-5 (SiO.sub.2/Al.sub.2O.sub.3=27, 150, 300, respectively), zeolites from laboratory synthesis, e.g. HZSM-23 (SiO.sub.2/Al.sub.2O.sub.3=80) and zeolites from Zeolyst company, e.g. HBEA (SiO.sub.2/Al.sub.2O.sub.3=25), HMOR (SiO.sub.2/Al.sub.2O.sub.3=20).

[0041] 0.5 g said prepared Na/Fe.sub.3O.sub.4 granules and 0.5 g said HY or HBEA or HMOR or HZSM-23 or HMCM-22 or HZSM-5 zeolite granules were mixed homogenously for the catalyst evaluation in the fixed-bed reactor for CO.sub.2 hydrogenation reaction. Reducing conditions: 1 atm, pure H.sub.2 (25 mL/min), and 350 C. for 8 h. Reaction conditions: H.sub.2/CO.sub.2=3.0, 320 C., 3.0 MPa, and GHSV (Gas hourly space velocity): 4000 mL/(h.Math.g.sub.cat). Influences of different zeolites on the FeNa/Zeolite catalyst for CO.sub.2 hydrogenation has been carried out, the results (Table 1) indicated that, hydrocarbon product distribution of CO.sub.2 hydrogenation was affected by the channel and pore structure, the catalyst containing ZSM-5 exhibits excellent performances in the CO.sub.2 hydrogenation due to the structure of HZSM-5: a three-dimensional porous network with two groups of interconnected 10-ring channels: ellipsoidal 5.35.6 and sinusoidal 5.15.5 and without cages at intersections. Gasoline-range hydrocarbon content in hydrocarbons varies with different kinds of zeolites: HZSM-5>HMCM-22>HZSM-23>HY>HBEA>HMOR. In addition, the product distribution of CO.sub.2 hydrogenation is also influenced by the acidic strength of zeolites, HZSM-5 with SiO.sub.2/Al.sub.2O.sub.3=150 and suitable acidic sites and strength, made the NaFe.sub.3O.sub.4/HZSM-5 catalyst exhibit the best CO.sub.2 hydrogenation performance and highest selectivity to the gasoline-range hydrocarbons.

TABLE-US-00001 TABLE 1 Influences of zeolites on the FeNa/Zeolite hybrid catalysts for CO.sub.2 hydrogenation Conv.* Selec.* Hydrocarbon distribution CO.sub.2 CO (C-mol %) Zeolite (%) (%) CH.sub.4 C.sub.2~C.sub.4 C.sub.5~C.sub.11 C.sub.12+ O/P.sup.a i-C.sub.5/n-C.sub.5.sup.b .sup.c 34.0 14.3 11.7 48.4 37.9 2.0 6.2 1.4 HMOR 35.0 12.0 9.8 47.2 42.8 0.2 4.5 1.2 HBEA 35.3 11.8 10.7 44.7 43.9 0.7 2.0 3.5 HY 34.1 13.7 10.0 40.5 47.9 1.6 1.2 4.1 HZSM-23 33.7 14.7 10.6 37.8 51.0 0.6 3.2 1.1 HMCM-22 34.8 13.4 11.0 31.3 56.8 0.9 0.5 6.7 HZSM-5(27) 33.6 13.9 7.3 24.5 64.4 3.7 0.0 4.3 HZSM-5(150) 33.6 15.0 7.9 18.4 73.0 0.7 0.1 3.0 HZSM-5(300) 33.0 15.0 8.6 23.2 67.3 0.9 1.2 1.7 .sup.aO/P means the molar ratio of olefins to paraffins in C.sub.2-4 hydrocarbons. If no special description, O/P means the same meaning in the subsequent tables. .sup.bi-C.sub.5/n-C.sub.5 means the molar ratio of iso-pentanes to normal-pentane. If no special description, i-C.sub.5/n-C.sub.5 has the same meaning in the subsequent tables. .sup.cmeans loading Na/Fe.sub.3O.sub.4 only and without zeolite loading. *Conv. means conversion and Selec. means selectivity, if no special description, the same meaning of them in the subsequent form.

Example 2

[0042] According to the different mass ratio, weight Na/Fe.sub.3O.sub.4 and HZSM-5 (SiO.sub.2/Al.sub.2O.sub.3=150), which was prepared in Example 1, and homogenously mix them to form 1 g of a granule hybrid catalyst for CO.sub.2 hydrogenation reaction. Reducing conditions: 1 atm, pure H.sub.2 (25 mL/min), and 350 C. for 8 h. Reaction conditions: H.sub.2/CO.sub.2=3.0, 320 C., 3.0 MPa, and GHSV: 4000 mL/(h.Math.g.sub.cat). Influences of mass ratio of Na/Fe.sub.3O.sub.4 to HZSM-5 on the FeNa/Zeolite catalyst for CO.sub.2 hydrogenation has been carried out, the results (Table 2) show that, the hybrid catalyst exhibit multifunctional performances and there exists a synergistic effect between Na/Fe.sub.3O.sub.4 and HZSM-5. The hybrid catalyst exhibits the optimal reaction performances and the highest selectivity to gasoline-range hydrocarbons at 1 of NaFe.sub.3O.sub.4 to ZSM-5 mass ratio.

TABLE-US-00002 TABLE 2 Influences of the mass ratio of Na/Fe.sub.3O.sub.4 to HZSM-5 on the FeNa/HZSM-5(150) catalyst for CO.sub.2 hydrogenation Conv. Selec. Hydrocarbon distribution Fe/ZSM* CO.sub.2 CO (C-mol %) (wt./wt.) (%) (%) CH.sub.4 C.sub.2~C.sub.4 C.sub.5~C.sub.11 C.sub.12+ O/P i-C.sub.5/n-C.sub.5 1:7 29.0 19.4 6.7 22.9 68.7 1.7 0.2 3.8 1:3 32.9 15.4 7.1 20.6 71.3 1.0 0.1 3.4 1:1 33.6 15.2 7.9 18.4 73.0 0.7 0.1 3.0 3:1 35.0 14.5 9.2 20.4 70.1 0.3 0.6 2.4 7:1 35.8 14.0 10.0 24.0 65.7 0.3 1.4 2.0 *Fe/ZSM mean NaFe.sub.3O.sub.4/HZSM-5, if no special description, it has the same meaning in the subsequent tables.

Example 3

[0043] Weight 0.5 g Na/Fe.sub.3O.sub.4 and 0.5 g HZSM-5 (SiO.sub.2/Al.sub.2O.sub.3=150), which were prepared in Example 1, respectively. Homogenously mix them to form 1 g of a granule hybrid catalyst for CO.sub.2 hydrogenation reaction. Reducing conditions: 1 atm, pure H.sub.2 (25 mL/min), and 350 C. for 8 h. Reaction conditions: H.sub.2/CO.sub.2=3.0, 280-380 C., 3.0 MPa, and GHSV: 2000 mL/(h.Math.g.sub.cat). Influences of reaction temperature on the FeNa/Zeolite catalyst for CO.sub.2 hydrogenation has been carried out, the results (Table 3) show that, with increasing temperature from 280 to 380 C., conversion of CO.sub.2 increases and the content of gasoline-range hydrocarbons in hydrocarbons increases before 320 C. and then decreases. The catalyst shows excellent catalytic performances for CO.sub.2 hydrogenation to gasoline-range hydrocarbons at the investigated temperatures.

TABLE-US-00003 TABLE 3 Influences of reaction temperature on the FeNa/HZSM- 5(150) catalyst for CO.sub.2 hydrogenation Conv Selec. Hydrocarbon distribution Temperature CO.sub.2 CO (C-mol %) ( C.) (%) (%) CH.sub.4 C.sub.2~C.sub.4 C.sub.5~C.sub.11 C.sub.12+ O/P i-C.sub.5/n-C.sub.5 280 25.2 14.3 9.8 22.1 67.9 0.2 0.3 1.8 300 34.5 9.1 8.7 22.0 69.3 0.1 0.2 2.5 320 40.1 8.2 8.0 21.6 69.7 0.7 0.1 3.3 340 44.1 9.2 8.6 25.1 66.2 0.0 0.1 4.0 360 46.3 10.5 9.2 27.1 63.4 0.4 0.1 4.6 380 48.4 11.9 12.0 30.3 57.4 0.3 0.1 5.0

Example 4

[0044] Weight 0.5 g Na/Fe.sub.3O.sub.4 and 0.5 g HZSM-5 (SiO.sub.2/Al.sub.2O.sub.3=150), which were prepared in Example 1, respectively. Homogenously mix them to form 1 g of a granule hybrid catalyst for CO.sub.2 hydrogenation reaction. Reducing conditions: 1 atm, pure H.sub.2 (25 mL/min), and 350 C. for 8 h. Reaction conditions: H.sub.2/CO.sub.2=3.0, 320 C., 1.0-5.0 MPa, and GHSV: 2000 mL/(h.Math.g.sub.cat). Influences of reaction pressure on the FeNa/Zeolite catalyst for CO.sub.2 hydrogenation has been carried out, the results (Table 4) show that, with increasing pressure from 1.0 to 5.0 MPa, conversion of CO.sub.2 increases and the content of gasoline-range hydrocarbons in hydrocarbons increases before 3.0 MPa and then decreases, and selectivity to CO decreases. The catalyst show excellent catalytic performances for CO.sub.2 hydrogenation to gasoline-range hydrocarbons at the investigated pressures.

TABLE-US-00004 TABLE 4 Influences of reaction pressure on the FeNa/HZSM- 5(150) catalyst for CO.sub.2 hydrogenation Conv. Selec. Hydrocarbon distribution P CO.sub.2 CO (C-mol %) (MPa) (%) (%) CH.sub.4 C.sub.2~C.sub.4 C.sub.5~C.sub.11 C.sub.12+ O/P i-C.sub.5/n-C.sub.5 1.0 31.2 24.3 8.9 28.4 60.7 2.0 0.4 3.8 2.0 33.8 16.5 9.5 24.4 63.2 2.9 0.2 3.5 3.0 38.6 10.4 8.5 21.0 69.8 0.8 0.2 3.3 4.0 40.7 8.0 10.4 22.9 65.9 0.8 0.2 3.2 5.0 42.2 7.1 12.7 24.8 61.4 1.2 0.1 3.1

Example 5

[0045] Weight 0.5 g Na/Fe.sub.3O.sub.4 and 0.5 g HZSM-5 (SiO.sub.2/Al.sub.2O.sub.3=150), which were prepared in Example 1, respectively. Homogenously mix them to form 1 g of a granule hybrid catalyst for CO.sub.2 hydrogenation reaction. Reducing conditions: 1 atm, pure H.sub.2 (25 mL/min), and 350 C. for 8 h. Reaction conditions: 142/CO.sub.2=3.0, 320 C., 3.0 MPa, and GHSV: 1000-10000 mL/(h.Math.g.sub.cat). Influences of reaction GHSV of feedstocks on the FeNa/Zeolite catalyst for CO.sub.2 hydrogenation has been carried out, the results (Table 5) show that, with increasing GHSV from 1000 to 10000 mL/(h.Math.g.sub.cat), conversion of CO.sub.2 decreases and the content of gasoline-range hydrocarbons in hydrocarbons increases before 4000 mL/(h.Math.g.sub.cat) and then decreases. Over the hybrid catalyst, high CO.sub.2 conversion (28.7%) and high content of C.sub.5-11 hydrocarbons (63.3%) at 10000 mL/(h.Math.g.sub.cat) of feedstock GHSV.

TABLE-US-00005 TABLE 5 Influences of feedstock GHSV on the FeNa/HZSM- 5(150) catalyst for CO.sub.2 hydrogenation Conv. Selec. Hydrocarbon distribution GHSV CO.sub.2 CO (C-mol %) (mL .Math. g.sup.1 .Math. h.sup.1) (%) (%) CH.sub.4 C.sub.2~C.sub.4 C.sub.5~C.sub.11 C.sub.12+ O/P i-C.sub.5/n-C.sub.5 1000 43.1 9.4 10.5 25.4 63.4 0.7 0.1 3.9 2000 37.2 11.2 8.3 21.3 69.7 0.7 0.1 3.5 4000 33.2 17.0 7.8 19.0 72.1 1.1 0.2 3.0 6000 31.7 19.0 8.0 20.2 70.4 1.5 0.3 2.7 8000 30.3 22.3 8.2 20.6 69.2 2.0 0.5 2.5 10000 28.7 25.0 8.4 21.4 68.0 2.2 0.7 2.3

Example 6

[0046] Weight 0.5 g Na/Fe.sub.3O.sub.4 and 0.5 g HZSM-5 (SiO.sub.2/Al.sub.2O.sub.3=150), which were prepared in Example 1, respectively. Homogenously mix them to form 1 g of a granule hybrid catalyst for CO.sub.2 hydrogenation reaction. Reducing conditions: 1 atm, pure H.sub.2 (25 mL/min), and 350 C. for 8 h. Reaction conditions: H.sub.2/CO.sub.2=1.0-6.0, 320 C., 3.0 MPa, and GHSV: 2000 mL/(h.Math.g.sub.cat). Influences of H.sub.2/CO.sub.2 ratio in feedstocks on the FeNa/Zeolite catalyst for CO.sub.2 hydrogenation has been carried out, the results (Table 6) show that, with increasing H.sub.2/CO.sub.2 ratio from 1.0 to 6.0, conversion of CO.sub.2 evidently increases, the content of gasoline-range hydrocarbons in hydrocarbons keep high value during the investigated H.sub.2/CO.sub.2 ratios.

TABLE-US-00006 TABLE 6 Influences of feedstock H.sub.2/CO.sub.2 ratio on the FeNa/HZSM-5(150) catalyst for CO.sub.2 hydrogenation Conv. Selec. Hydrocarbon distribution Ratio CO.sub.2 CO (C-mol %) H.sub.2/CO.sub.2 (%) (%) CH.sub.4 C.sub.2~C.sub.4 C.sub.5~C.sub.11 C.sub.12+ O/P i-C.sub.5/n-C.sub.5 1.0 22.0 17.6 4.3 19.5 75.0 1.2 0.1 3.4 2.0 27.1 16.5 6.5 20.3 72.3 1.0 0.1 3.4 3.0 36.0 13.1 8.6 20.8 70.0 0.7 0.1 3.4 4.0 45.0 9.7 10.5 21.3 68.0 0.2 0.1 3.4 5.0 53.1 7.4 11.5 21.4 66.7 0.4 0.1 3.4 6.0 59.5 5.7 12.9 22.2 64.6 0.3 0.1 3.4

Example 7

[0047] 0.72 g Ga(NO.sub.3).sub.3.9H.sub.2O was weighted and dissolved into 7.2 mL deioned water to form solution of Ga(NO.sub.3).sub.3; then 6.0 g HZSM-5 (SiO.sub.2/Al.sub.2O.sub.3=150) was weighted and impregnated into the above solution of Ga(NO.sub.3).sub.3. After stirring, stewing 12 h, drying at 60 C., calcination at 500 C. for 4 h, the Ga-modified zeolite was obtained after being ground, pelleted, and sieved. The preparation method of other metal-modified zeolites (MZSM-5) is similar as that of Ga-ZSM-5.

[0048] Weight 0.5 g Na/Fe.sub.3O.sub.4 prepared in Example 1 and 0.5 g 2% MZSM-5 as prepared, respectively. Homogenously mix them to form 1 g of a granule hybrid catalyst for CO.sub.2 hydrogenation reaction. Reducing conditions: 1 atm, pure H.sub.2 (25 mL/min), and 350 C. for 8 h. Reaction conditions: H.sub.2/CO.sub.2=3.0, 320 C., 3.0 MPa, and GHSV: 4000 mL/(h.Math.g.sub.cat). Influences of metal modification of HZSM-5 on the FeNa/Zeolite catalyst for CO.sub.2 hydrogenation has been carried out, the results (Table 7) show that, metal modification of HZSM-5 zeolite has little influences on CO.sub.2 conversion, but evidently influenced the product composition, the content of gasoline-range hydrocarbons in hydrocarbons decreases at different degrees with different metal modification.

TABLE-US-00007 TABLE 7 Influences of metal modification of HZSM-5 on the FeNa/HZSM-5(150) catalyst for CO.sub.2 hydrogenation Conv. Selec. Hydrocarbon distribution CO.sub.2 CO (C-mol %) M (%) (%) CH.sub.4 C.sub.2~C.sub.4 C.sub.5~C.sub.11 C.sub.12+ O/P i-C.sub.5/n-C.sub.5 .sup.a 33.6 15.2 7.9 18.4 73.0 0.7 0.1 3.0 Mo 33.6 16.8 7.9 18.8 72.4 0.9 0.1 2.9 Cr 35.0 14.3 8.4 20.5 70.9 0.2 0.4 2.5 La 35.7 13.8 8.6 20.7 70.6 0.1 0.5 2.3 Ga 35.6 14.0 7.9 20.2 70.1 1.8 0.1 3.4 Zn 35.0 13.9 8.6 22.8 68.1 0.4 1.3 1.8 Cu 35.9 13.6 8.1 24.1 67.7 0.1 0.2 3.0 Co 34.4 12.0 22.0 44.4 33.5 0.1 0.0 1.2 .sup.aUnmodified zeolite.

Example 8

[0049] Weight 0.5 g Na/Fe.sub.3O.sub.4 and 0.5 g HZSM-5 (SiO.sub.2/Al.sub.2O.sub.3=150), which were prepared in Example 1, respectively. Na/Fe.sub.3O.sub.4 and HZSM-5 were packed into the reactor according to the sequences of iron-based catalyst layer, and zeolite layer, among which iron-based catalyst layer is near to the feedstock inlet, there is an isolated layer composed of inert quartz sands between iron-based catalyst layer and zeolite layer. Then the reactor with hybrid catalyst form was carried out the catalytic stability test of CO.sub.2 hydrogenation reaction. Reducing conditions: 1 atm, pure H.sub.2 (25 mL/min), and 350 C. for 8 h. Reaction conditions: H.sub.2/CO.sub.2=3.0, 320 C., 3.0 MPa, and GHSV: 4000 mL/(h.Math.g.sub.cat). The results (Table 8) show that, the loading hybrid catalyst exhibit excellent performances of CO.sub.2 hydrogenation during 1000 h reaction, there is no evident deactivation found for this hybrid catalyst. The composition analysis (Table 9) of gasoline products show that gasoline-range hydrocarbons are mainly composed of isoparaffins and aromatics, the content of olefins in gasoline is low, the composition of gasoline products meet the requirement of standard China-V gasoline.

TABLE-US-00008 TABLE 8 1000 h catalytic stability test results of FeNa/HZSM-5(150) catalyst with multilayer catalyst packing method for CO.sub.2 hydrogenation Time on Conv. Selec. Hydrocarbon distribution Stream CO.sub.2 CO (C-mol %) i-C.sub.5/ (h) (%) (%) CH.sub.4 C.sub.2~C.sub.4 C.sub.5~C.sub.11 C.sub.12+ O/P n-C.sub.5 4 33.2 14.6 9.3 24.0 66.2 0.5 0.1 3.3 100 32.2 14.9 8.8 22.4 67.7 1.1 0.1 3.1 200 29.6 17.5 8.8 21.9 67.6 1.6 0.1 3.1 300 28.1 18.1 9.6 23.0 66.4 1.1 0.1 3.2 400 27.4 19.0 9.7 23.2 65.9 1.2 0.1 3.2 500 27.5 18.7 10.0 23.7 65.3 1.0 0.2 3.2 600 27.0 19.2 10.1 24.4 65.0 0.5 0.2 3.1 700 27.3 18.9 10.1 24.1 65.1 0.7 0.2 3.1 800 26.8 19.6 10.1 24.2 64.9 0.8 0.2 3.1 900 26.7 19.9 10.1 24.5 64.5 0.8 0.2 3.1 1000 26.8 19.8 10.2 24.6 64.3 0.9 0.2 3.1

TABLE-US-00009 TABLE 9 Composition of gasoline product at reaction 1000 h Gasoline-range hydrocarbons Content (C-mol %) Normal paraffins 8.0 Olefins 5.4 Isoparaffins 44.0 Cyclanes 12.6 Aromatics 30.0

[0050] For this invention of CO.sub.2 hydrogenation to gasoline, the single-pass conversion of CO.sub.2 could achieve more than 33%, in hydrocarbon products, selectivity to methane is lower than 8%, selectivity to C.sub.5-11 gasoline-range hydrocarbons is higher than 70%, and the gasoline products with high octane-number were mainly composed of isoparaffins and aromatics. A new route for gasoline production from carbon dioxide was invented in this application.