Solid acid catalyst for producing light olefins and process using the same
View Patent ↗A porous solid acid catalyst for producing light olefins is prepared through pillaring and a solid state reaction of a raw material mixture. The catalyst is made of a porous material having a crystalline structure that is different from that of the raw material mixture. The catalyst exhibits excellent catalytic activity (i.e., conversion and selectivity) in the production of light olefins from hydrocarbon feeds such as full range naphthas.
1. A porous solid acid catalyst for producing light olefins, comprising a product formed by a pillaring reaction and a solid state reaction through heat treatment of a raw material mixture, and has a crystalline structure represented by an X-ray diffraction pattern as follows:
2θ
Relative intensity
7.899
81.4
8.760
48.1
14.76
15.3
19.92
15.2
20.36
21.2
23.06
100
23.88
59.7
24.36
24.5
25.60
15.3
25.82
18.4
26.60
22.2
26.86
20.8
29.90
22.5
45.00
17.5
45.48
17.4
wherein the raw material mixture comprises 42.0-60.0 wt % HZSM-5 having Si/Al molar ratio of 15-300, 12.0-38.0 wt % layered compound, 1.0-20.0 wt % Al 2 O 3 , 1.0-4.0 wt % P 2 O 5 , 10.0-15.0 wt % SiO 2 , and 0.5-2.5 wt % B 2 O 3 based on an oxide form.
2. The catalyst as set forth in claim 1 , wherein the catalyst has a specific surface area of 200-400 m 2 /g.
3. The catalyst as set forth in claim 1 , wherein the catalyst is a pelletized catalyst.
4. A method for producing a porous solid acid catalyst for producing light olefins, comprising the steps of:
carrying out a pillaring reaction of a raw material mixture comprising 42.0-60.0 wt % HZSM-5 having Si/Al molar ratio of 15-300, 12.0-38.0 wt % layered compound, 1.0-20.0 wt % Al 2 O 3 as a pillaring agent, 1.0-4.0 wt % P 2 O 5 , 10.0-15.0 wt % SiO 2 , and 0.5-2.5 wt % B 2 O 3 based on an oxide form in water to form an aqueous slurry containing the pillared product;
pelletizing the aqueous slurry to form a pelletized catalyst; and
performing a solid state reaction of the pelletized catalyst under a heat treatment condition sufficient to give a crystalline structure having an X-ray pattern diffraction pattern as follows:
2θ
Relative intensity
7.899
81.4
8.760
48.1
14.76
15.3
19.92
15.2
20.36
21.2
23.06
100
23.88
59.7
24.36
24.5
25.60
15.3
25.82
18.4
26.60
22.2
26.86
20.8
29.90
22.5
45.00
17.5
45.48
17.4.
5. The method as set forth in claim 4 , wherein the pelletizing step is conducted by use of spray drying.
6. The method as set forth in claim 4 , wherein the step of performing a solid state reaction further comprises the steps of:
conducting a first heat treatment in an inert atmosphere at 450-600° C. for 3-5 hours; and
conducting a second heat treatment in the presence of oxygen at 550-700° C. for 3-5 hours.
7. The method as set forth in claim 6 , wherein the step of conducting the first heat treatment is conducted in a nitrogen atmosphere, while the step of conducting the second heat treatment is conducted in an air atmosphere.
8. The method as set forth in claim 4 , wherein the step of carrying out a pillaring reaction further comprises the steps of:
providing an aqueous pillaring-binding solution comprising a mixture of an aluminum compound and a phosphorus compound in water, wherein Al/P has a molar ratio ranging within 0.7-1.4 based on the oxide form;
providing a slurry comprising: HZSM-5; the layered compound; and a silicon compound in water; and
mixing the aqueous pillaring-binding solution, the slurry, and a boron compound for a time sufficient to cause a pillaring reaction between layers of the layered compound to prepare the aqueous slurry containing the pillared product in the step of carrying out a pillaring reaction.
9. The method as set forth in claim 8 , wherein the aluminum compound is selected from a group consisting of Al(NO 3 ) 3 , Al 2 (SO 4 ) 3 , AlCl 3 , and a mixture thereof.
10. The method as set forth in claim 8 , wherein the phosphorus compound is selected from a group consisting of H 3 PO 4 , (NH 4 ) 2 HPO 4 , (NH 4 )(H 2 PO 4 ) and a mixture thereof.
11. The method as set forth in claim 8 , wherein the layered compound is Kaolin, bentonite, saponite, or a mixture thereof.
12. The method as set forth in claim 8 , wherein the boron compound is in a boric acid aqueous solution form.
13. The method as set forth in claim 8 , wherein a solid content in the slurry ranges within 48.0-60.0 wt %.
14. The method as set forth in claim 8 , wherein the mixing step is conducted with agitation for 10-15 hours.