Catalyst for synthesizing aromatic hydrocarbons and preparation method therefor

Abstract

A catalyst for synthesizing aromatic hydrocarbons, a preparation method thereof and a method for synthesizing aromatic hydrocarbons by using the catalyst. The catalyst comprises acidic molecular sieve particles and zinc-aluminum composite oxide particles. The catalyst has relatively high selectivity to aromatic hydrocarbons, particularly BTX, stable performance, and a long single-pass life.

Claims

1. A catalyst, wherein the catalyst comprises a uniform mixture of acidic molecular sieve particles and coprecipitated zinc-aluminum composite oxide particles, and the zinc-aluminum composite oxide particles further comprise impregnated palladium oxide and zirconium oxide.

2. The catalyst according to claim 1, wherein a mass ratio of the acidic molecular sieve particles to the zinc-aluminum composite oxide particles is in a range from 1:19 to 19:1.

3. The catalyst according to claim 1, wherein the acidic molecular sieve particles and the zinc-aluminum composite oxide particles each independently have a diameter of less than or equal to 5 mm.

4. The catalyst according to claim 1, wherein the acidic molecular sieve is an acidic molecular sieve selected from the group consisting of 10-membered ring molecular sieves and molecular sieves having greater than 10-membered rings.

5. The catalyst according to claim 1, wherein the acidic molecular sieve comprises an acidic molecular sieve with at least one structure selected from a group consisting of MFI, BEA, FAU, EMT, MOR, FER, and MWW.

6. The catalyst according to claim 2, wherein the acidic molecular sieve particles and the zinc-aluminum composite oxide particles each independently have a diameter of less than or equal to 5 mm.

7. The catalyst according to claim 2, wherein the acidic molecular sieve is an acidic molecular sieve selected from the group consisting of 10-membered ring molecular sieves and molecular sieves having greater than 10-membered rings.

8. The catalyst according to claim 3, wherein the acidic molecular sieve is an acidic molecular sieve selected from the group consisting of 10-membered ring molecular sieves and molecular sieves having greater than 10-membered rings.

9. The catalyst according to claim 1, wherein the acidic molecular sieve particles and the zinc-aluminum composite oxide particles each independently have a diameter of less than or equal to 1 mm and greater than or equal to 0.1 mm.

10. The catalyst according to claim 1, wherein, the acidic molecular sieve is an acidic ZSM-5 molecular sieve.

11. The catalyst according to claim 1, wherein, the acidic molecular sieve is an acidic ZSM-5 molecular sieve exchanged with NH4+ ions followed by air calcination resulting in the H+ acidic form of ZSM-5.

12. The catalyst according to claim 1, wherein the catalyst has been prepared by a method comprising 1) Formulating a salt containing metal ions from a zinc element and an aluminum element into an aqueous solution, 2) Coprecipitating the metal ions in the salt containing the zinc element and the aluminum element by an aqueous solution of a precipitating agent to obtain a precipitate, 3) Aging, washing, drying and calcining the precipitate to obtain the coprecipitated zinc-aluminum composite oxide particles, and impregnating the coprecipitated zinc-aluminum composite oxide particles with a mixed solution containing salt compounds of palladium and zirconium followed by drying and calcining to obtain the zinc-aluminum composite oxide particles comprising palladium oxide and zirconium oxide, 4) Uniformly mixing the zinc-aluminum composite oxide particles comprising palladium oxide and zirconium oxide with the acidic molecular sieve particles; wherein the precipitating agent comprises at least one selected from a group consisting of sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, ammonium hydrogencarbonate, aqueous ammonia, sodium hydroxide, and potassium hydroxide.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) The application will be described in detail below with reference to examples, but the application is not limited to the examples.

(2) The raw materials in the examples of the present application are all commercially purchased unless otherwise stated.

(3) The analytical methods and the calculation methods for conversion rate and selectivity in the examples are as follows:

(4) Automated analysis is performed using an Agilent 7890 gas chromatograph with a gas autosampler, a TCD detector connected to a TDX-1 packed column, and an FID detector connected to a FFAP capillary column.

(5) In some embodiments of the application, both the conversion rate and the selectivity are calculated based on the number of moles of carbon:
The conversion rate of carbon monoxide=[(mole number of carbon in carbon monoxide in the feed)−(mole number of carbon in carbon monoxide in the discharge)]÷(mole number of carbon in carbon monoxide in the feed)×100%
The selectivity to aromatic hydrocarbons=(mole number of carbon in aromatic hydrocarbons in the discharge)÷(mole number of carbon in all hydrocarbon products in the discharge)×100%
The selectivity to BTX=(mole number of carbon in BTX in the discharge)÷(mole number of carbon in all hydrocarbon products in the discharge)×100%

(6) The application is described in detail below by means of examples, but the application is not limited to the examples.

(7) The Preparation of Catalyst

Example 1

(8) The sodium type ZSM-5 (Catalyst Factory of Nankai University) with Si/Al=19 (atomic ratio) is exchanged with 0.8 mol/L aqueous ammonium nitrate solution at 80 for 3 times to obtain an ammonium type ZSM-5 molecular sieve. The ammonium type ZSM-5 molecular sieve is calcined at 550° C. for 4 hours in an air atmosphere, tabletted, crushed and then sieved to obtain acidic ZSM-5 molecular sieve particles of 0.25 mm-0.50 mm scale.

(9) 1 L nitrate solution mixed with 0.25 mol/L Zn.sup.2+ and 0.50 mol/L Al.sup.3+ is prepared. 0.5 mol/L sodium carbonate solution is added in the nitrate solution slowly, coprecipitation reaction temperature is controlled at 70° C., and pH value is kept at about 7.0 to coprecipitate metal ions and the coprecipitated metal ions are aged at this temperature for 2 hours, filtered, washed, dried, and calcined at 500° C. for 2 hours, tabletted, crushed and then sieved to obtain zinc-aluminum composite oxide (ZnAlO.sub.x) particles of 0.25 mm-0.50 mm scale.

(10) 4 g of the above acidic ZSM-5 molecular sieve particles are uniformly mixed with 1 g of the above ZnAlO.sub.x particles to prepare a catalyst A.

Example 2

(11) The sodium type ZSM-5 (Catalyst Factory of Nankai University) with Si/Al=19 (atomic ratio) is exchanged with 0.8 mol/L aqueous ammonium nitrate solution at 80 for 3 times to obtain an ammonium type ZSM-5 molecular sieve. The ammonium type ZSM-5 molecular sieve is calcined at 550° C. for 4 hours in an air atmosphere, tabletted, crushed and then sieved to obtain acidic ZSM-5 molecular sieve particles of 0.25 mm-0.50 mm scale.

(12) 1 L nitrate solution mixed with 0.25 mol/L Zn.sup.2+ and 0.50 mol/L Al.sup.3+ is prepared, 0.5 mol/L ammonium carbonate solution is added in the nitrate solution slowly, coprecipitation reaction temperature is controlled at 70° C., and pH value is kept at about 7.0 to coprecipitate metal ions and the coprecipitated metal ions are aged at this temperature for 2 hours, filtered, washed, dried, and calcined at 500° C. for 2 hours to obtain zinc-aluminum composite oxide powder. Cr(NO.sub.3).sub.3 solution with a Cr.sup.2+ concentration of 0.25 mol/L is used to impregnate the zinc-aluminum composite oxide powder at room temperature for 24 hours, followed by drying and calcining the zinc-aluminum composite oxide powder at 500° C. for 2 hours to obtain a modified zinc-aluminum composite oxide powder containing 5% chromium (5% Cr—ZnAlO.sub.x). The 5% Cr—ZnAlO.sub.x powder is tableted, crushed and sieved to obtain particles of 0.25 mm-0.50 mm scale.

(13) 4 g of the above acidic ZSM-5 molecular sieve particles are uniformly mixed with 1 g of the above 5% Cr—ZnAlO.sub.x particles to prepare a catalyst B.

Example 3

(14) The sodium type ZSM-5 (Catalyst Factory of Nankai University) with Si/Al=19 (atomic ratio) is exchanged with 0.8 mol/L aqueous ammonium nitrate solution at 80 for 3 times to obtain an ammonium type ZSM-5 molecular sieve. The ammonium type ZSM-5 molecular sieve is calcined at 550° C. for 4 hours in an air atmosphere, tabletted, crushed and then sieved to obtain acidic ZSM-5 molecular sieve particles of 0.25 mm-0.50 mm scale.

(15) 1 L nitrate solution mixed with 0.1 mol/L Zn.sup.2+ and 2.0 mol/L Al.sup.3+ is prepared, 0.5 mol/L sodium carbonate solution is added in the nitrate solution slowly, coprecipitation reaction temperature is controlled at 70° C., and pH value is kept at about 7.0 to coprecipitate metal ions and the coprecipitated metal ions are aged at this temperature for 2 hours, filtered, washed, dried, and calcined at 500° C. for 2 hours to obtain Zn—Al composite oxide powder. Cu(NO.sub.3).sub.2 solution with a Cu.sup.2+ concentration of 0.4 mol/L is used to impregnate the zinc-aluminum composite oxide powder at room temperature for 24 hours, followed by drying and calcining the zinc-aluminum composite oxide powder at 500° C. for 2 hours to obtain a modified zinc-aluminum composite oxidepowder containing 7% copper (7% Cu—ZnAlO.sub.x). The 7% Cu—ZnAlO.sub.x powder is tableted, crushed and sieved to obtain particles of 0.25 mm-0.50 mm scale.

(16) 4 g of the above acidic ZSM-5 molecular sieve particles are uniformly mixed with 1 g of the above 7% Cu—ZnAlO.sub.x particles to prepare a catalyst C.

Example 4

(17) The sodium type ZSM-5 (Catalyst Factory of Nankai University) with Si/Al=19 (atomic ratio) is exchanged with 0.8 mol/L aqueous ammonium nitrate solution at 80 for 3 times to obtain an ammonium type ZSM-5 molecular sieve. The ammonium type ZSM-5 molecular sieve is calcined at 550° C. for 4 hours in an air atmosphere, tabletted, crushed and then sieved to obtain acidic ZSM-5 molecular sieve particles of 0.25 mm-0.50 mm scale.

(18) 1 L nitrate solution mixed with 2.0 mol/L Zn.sup.2+ and 0.1 mol/L Al.sup.3+ is prepared, 0.5 mol/L sodium carbonate solution is added in the nitrate solution slowly, coprecipitation reaction temperature is controlled at 70° C., and pH value is kept at about 7.0 to coprecipitate metal ions and the coprecipitated metal ions are aged at this temperature for 2 hours, filtered, washed, dried, and calcined at 500° C. for 2 hours to obtain zinc-aluminum composite oxide powder. A mixed solution of Cr(NO.sub.3).sub.3 solution with a Cr.sup.2+ concentration of 0.1 mol/L and Zr(NO.sub.3).sub.4 solution with a Zr.sup.4+ concentration of 0.2 mol/L is used to impregnate the zinc-aluminum composite oxide powder at room temperature for 24 hours, followed by drying and calcining the zinc-aluminum composite oxide powder at 500° C. for 2 hours to obtain a modified zinc-aluminum composite oxide powder containing 2% chromium and 4% zirconium (2% Cr—4% Zr—ZnAlO.sub.x). The 2% Cr—4% Zr—ZnAlO.sub.x powder is tableted, crushed and sieved to obtain particles of 0.25 mm-0.50 mm scale.

(19) 4 g of the above acidic ZSM-5 molecular sieve particles are mixed with 1 g of the above 3% Cr—4% Zr—ZnAlO.sub.x particles uniformly to prepare a catalyst D.

Example 5

(20) The sodium type ZSM-5 (Catalyst Factory of Nankai University) with Si/Al=19 (atomic ratio) is exchanged with 0.8 mol/L aqueous ammonium nitrate solution at 80 for 3 times to obtain an ammonium type ZSM-5 molecular sieve. The ammonium type ZSM-5 molecular sieve is calcined at 550° C. for 4 hours in an air atmosphere, tabletted, crushed and then sieved to obtain acidic ZSM-5 molecular sieve particles of 0.25 mm-0.50 mm scale.

(21) 1 L nitrate solution mixed with 0.1 mol/L Zn.sup.2+ and 0.50 mol/L Al.sup.3+ is prepared, 0.5 mol/L sodium carbonate solution is added in the nitrate solution slowly, coprecipitation reaction temperature is controlled at 70° C., and pH value is kept at about 7.0 to coprecipitate metal ions and the coprecipitated metal ions are aged at this temperature for 2 hours, filtered, washed, dried, and calcined at 500° C. for 2 hours to obtain zinc-aluminum composite oxide powder. A mixed solution of Pd(NO.sub.3).sub.3 solution with a Pd.sup.2+ concentration of 0.1 mol/L and Zr(NO.sub.3).sub.4 solution with a Zr.sup.4+ concentration of 0.2 mol/L is used to impregnate the zinc-aluminum composite oxide powder at room temperature for 24 hours, followed by drying and calcining the zinc-aluminum composite oxide powder at 500° C. for 2 hours to obtain a modified zinc-aluminum composite oxide powder containing 3% palladium and 4% zirconium (3% Pd—4% Zr—ZnAlO.sub.x). The 3% Pd—4% Zr—ZnAlO.sub.x powder is tableted, crushed and sieved to obtain particles of 0.25 mm-0.50 mm scale.

(22) 4 g of the above acidic ZSM-5 molecular sieve particles are uniformly mixed with 1 g of the above 3% Pd—4% Zr—ZnAlO.sub.x particles to prepare a catalyst E.

Example 6

(23) The sodium type ZSM-5 (Catalyst Factory of Nankai University) with Si/Al=19 (atomic ratio) is exchanged with 0.8 mol/L aqueous ammonium nitrate solution at 80 for 3 times to obtain an ammonium type ZSM-5 molecular sieve. The ammonium type ZSM-5 molecular sieve is calcined at 550° C. for 4 hours in an air atmosphere to obtain an acidic ZSM-5 molecular sieve powder with a powder size of less than 0.1 mm.

(24) 1 L nitrate solution mixed with 0.25 mol/L Zn.sup.2+ and 0.50 mol/L Al.sup.3+ is prepared, 0.5 mol/L sodium carbonate solution is added in the nitrate solution slowly, coprecipitation reaction temperature is controlled at 70° C., and pH value is kept at about 7.0 to coprecipitate metal ions and the coprecipitated metal ions are aged at this temperature for 2 hours, filtered, washed, dried, and calcined at 500° C. for 2 hours to obtain a zinc-aluminum composite oxide (ZnAlO.sub.x) powder with a powder size of less than 0.1 mm.

(25) 1 g of the above acidic ZSM-5 molecular sieve powder after calcination is uniformly mixed with 4 g of the above ZnAlO.sub.x powder, tabletted, crushed and then sieved to obtain a catalyst F of 0.25-0.50 mm scale.

Example 7

(26) The sodium type ZSM-5 (AOKE company) with Si/Al=35 (atomic ratio) is exchanged with 0.8 mol/L aqueous ammonium nitrate solution at 80 for 3 times to obtain an ammonium type ZSM-5 molecular sieve. The ammonium type ZSM-5 molecular sieve is calcined at 550° C. for 4 hours in an air atmosphere, tabletted, crushed and then sieved to obtain acidic ZSM-5 molecular sieve particles of 0.25-0.50 mm scale.

(27) 1 L nitrate solution mixed with 0.25 mol/L Zn.sup.2+ and 0.50 mol/L Al.sup.3+ is prepared, 0.5 mol/L sodium carbonate solution is added in nitrate solution slowly, the coprecipitation reaction temperature is controlled at 70° C., and pH value is kept at about 7.0 to coprecipitate metal ions and the coprecipitated metal ions are aged at this temperature for 2 hours, filtered, washed, dried, and calcined at 500° C. for 2 hours, tableted, crushed and then sieved to obtain zinc-aluminum composite oxide (ZnAlO.sub.x) particles of 0.25 mm-0.50 mm scale.

(28) 2.5 g of the above acidic ZSM-5 molecular sieve particles are uniformly mixed with 2.5 g of the above ZnAlO.sub.x particles to prepare a catalyst G.

Example 8

(29) The sodium type ZSM-5 (Fuxutech company) with Si/Al=40 (atomic ratio) is exchanged with 0.8 mol/L aqueous ammonium nitrate solution at 80 for 3 times to obtain an ammonium type ZSM-5 molecular sieve. The ammonium type ZSM-5 molecular sieve is calcined at 550° C. for 4 hours in an air atmosphere, tabletted, crushed and then sieved to obtain acidic ZSM-5 molecular sieve particles of 0.25-0.50 mm scale.

(30) 1 L nitrate solution mixed with 0.25 mol/L Zn.sup.2+ and 0.50 mol/L Al.sup.3+ is prepared, 0.5 mol/L sodium carbonate solution is added in the nitrate solution slowly, coprecipitation reaction temperature is controlled at 70° C., and pH value is kept at about 7.0 to coprecipitate metal ions and the coprecipitated metal ions are aged at this temperature for 2 hours, filtered, washed, dried, and calcined at 500° C. for 2 hours, tableted, crushed and then sieved to obtain zinc-aluminum composite oxide (ZnAlO.sub.x) particles of 0.25 mm-0.50 mm scale.

(31) 4 g of the above acidic ZSM-5 molecular sieve particles are uniformly mixed with 1 g of the above ZnAlO.sub.x particles to prepare a catalyst H.

Example 9

(32) 1 g of the acidic ZSM-5 molecular sieve particles prepared in Example 1 is uniformly mixed with 19 g of the ZnAlO.sub.x particles prepared in Example 1, to prepare a catalyst I.

Example 10

(33) 19 g of the acidic ZSM-5 molecular sieve particles prepared in Example 1 is uniformly mixed with 1 g of the ZnAlO.sub.x particles prepared in Example 1 to prepare a catalyst J.

Example 11

(34) The particle diameters of the acidic ZSM-5 molecular sieve particles in Example 1 are prepared into 4.5 mm to 5 mm, and the particle diameters of the ZnAlO.sub.x particles in Example 1 are prepared into 4.5 mm to 5 mm. Other conditions are the same as that of Example 1. A catalyst K is prepared.

Example 12

(35) The particle diameters of the acidic ZSM-5 molecular sieve particles in Example 1 are prepared into 0.8 mm to 1 mm, and the particle diameters of the ZnAlO.sub.x particles in Example 1 are prepared into 0.8 mm to 1 mm. Other conditions are the same as that of Example 1. A catalyst L is prepared.

Example 13

(36) The particle diameters of the acidic ZSM-5 molecular sieve particles in Example 1 are prepared into 0.1 mm to 0.2 mm, and the particle diameters of the ZnAlO.sub.x particles in Example 1 are prepared into 0.1 mm to 0.2 mm. Other conditions are the same as that of Example 1. A catalyst M is prepared.

(37) Performance Test of Catalyst

Example 14

(38) 5 g Catalyst A is placed in a stainless steel reaction tube with an inner diameter of 8 mm and activated with 50 ml/min of hydrogen at 300 for 4 hours, and the reaction is carried out under the following conditions: reaction temperature (T)=400, reaction pressure (P)=4.0 MPa, volumetric space velocity (GHSV)=5000 h.sup.−1 under standard conditions, volume fraction of hydrogen in syngas (a mixed gas of CO and H.sub.2) V(H.sub.2)%=50%. After reacting for 500 hours, the product is analyzed by gas chromatography, and the results are shown in Table 1.

Examples 15-26

(39) The reaction conditions and reaction results are shown in Table 1. The other operations are the same as those in Example 14.

(40) TABLE-US-00001 TABLE 1 Catalytic reaction results in Examples 14-26 The The conversion selectivity rate of to The carbon aromatic selectivity Ex- Reaction monoxide hydrocarbon to BTX amples Catalyst conditions (%) (%) (%) 14 A T = 400; 30.5 80.3 75.2 P = 4.0 MPa; GHSV = 5000 h.sup.−1; V(H.sub.2) % = 50% 15 B T = 380; 75.1 77.3 68.9 P = 10.0 MPa; GHSV = 20000 h.sup.−1; V(H.sub.2) % = 90% 16 C T = 300; 12.4 82.1 79.6 P = 0.5 MPa; GHSV = 2000 h.sup.−1; V(H.sub.2) % = 10% 17 D T = 450; 50.4 74.6 70.0 P = 3.0 MPa; GHSV = 8000 h.sup.−1; V(H.sub.2) % = 75% 18 E T = 390; 25.9 83.9 70.8 P = 5.0 MPa; GHSV = 6000 h .sup.−1; V(H.sub.2) % = 40% 19 F T = 340; 30.9 74.9 66.9 P = 7.0 MPa; GHSV = 12000 h.sup.−1; V(H.sub.2) % = 60% 20 G T = 400; 28.9 77.0 73.6 P = 4.0 MPa; GHSV = 5000 h.sup.−1; V(H.sub.2) % = 50% 21 H T = 400; 25.9 78.8 65.2 P = 4.0 MPa; GHSV = 5000 h.sup.−1; V(H.sub.2) % = 50% 22 I T = 400; 50.5 68.4 60.1 P = 4.0 MPa; GHSV = 5000 h.sup.−1; V(H.sub.2) % = 50% 23 J T = 400; 22.4 84.3 80.1 P = 4.0 MPa; GHSV = 5000 h.sup.−1; V(H.sub.2) % = 50% 24 K T = 400; 25.4 77.9 72.1 P = 4.0 MPa; GHSV = 5000 h.sup.−1; V(H.sub.2) % = 50% 25 L T = 400; 28.8 78.6 74.2 P = 4.0 MPa; GHSV = 5000 h.sup.−1; V(H.sub.2) % = 50% 26 M T = 400; 30.0 80.1 75.0 P = 4.0 MPa; GHSV = 5000 h.sup.−1; V(H.sub.2) % = 50%
Regeneration Performance Test of Catalyst

Example 27

(41) The catalyst deactivated in Example 14 is treated at 550 for 10 hours with a gas mixture comprising 2% oxygen and 98% nitrogen by volume fraction to regenerate the catalyst for one cycle and the reaction is carried out under the conditions of Example 14. Five cycles of regeneration is conducted in the same manner, and the catalytic activity data after 500 hours of each reaction is selected for comparison. The results are shown in Table 2.

(42) TABLE-US-00002 TABLE 2 Catalytic reaction results in Example 27 The conversion The selectivity The rate of carbon to aromatic selectivity Life Times of monoxide hydrocarbon to BTX per regeneration (%) (%) (%) cycle 1 31.7 80.5 75.8 4000 2 30.8 81.3 74.9 4200 3 32.1 80.0 75.9 3900 4 31.0 79.6 74.8 3700 5 31.5 80.7 72.9 4100

(43) The above is only a few embodiments of the present application, and is not intended to limit the present application. The preferred embodiments are shown as above, but are not intended to limit the present application. A slight change or modification of the technical content disclosed above made by the person skilled in art without departing from the technical solution of the present application is equivalent to the equivalent embodiment, and is within the scope of the technical solution.