A method for preparing low-carbon olefins by catalytic synthesis gas conversion

A technology for syngas conversion and low-carbon olefins, which is applied in the field of catalysis and can solve problems such as cumbersome steps, harsh reaction conditions, and mismatched reaction temperatures

Inactive Publication Date: 2021-09-14
SHAANXI NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, scholars have conducted extensive research on Fischer-Tropsch synthesis, but there are still many key technologies in product selectivity regulation that have not been broken through. How to break through the traditional ASF distribution restrictions and prepare products with a specific range of C atoms with high selectivity become a current research hotspot
[0003] Zhao et al. (Chem 2017,3,2,334-347) combined Na-Zn-Fe 5 C 2 Mixed with mesoporous HZSM-5 molecular sieve to catalyze the conversion of synthesis gas, but found that the products were biased towards aromatics rather than low-carbon olefins; Hadadzadeh et al. (Petrol Chem, 2010, 50(1):78-86) used alumina, molecular sieves and other carriers FeMn catalyst and H 2 After S post-treatment, it was found that the S additive reduced the CH 4 Selectivity improves selectivity for lower olefins, but the process involves H 2 S treatment, the steps are relatively cumbersome; some scholars also prepare low-carbon olefins through a non-Fischer-Tropsch route, that is, coupling the traditional alcohol catalyst CuZnAl with mesoporous SAPO-34 molecular sieves to obtain low-carbon olefins (J Chem Technol Biotechnol.2015, 90 (3):415-422), but the reaction temperature does not match between the two, resulting in harsh reaction conditions

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] 1. According to Fe / Zn molar ratio is 1:1, Na / (Fe+Zn) mass ratio is 3%, 100mL 1mol / L FeSO 4 ·7H 2 O aqueous solution and 100mL 1mol / L Zn(NO 3 ) 3 ·6H 2 O aqueous solution was mixed and stirred for half an hour, and then 2mol / L Na was added dropwise 2 CO 3 The aqueous solution is used as a precipitating agent, the pH of the system is controlled to be 9, and co-precipitation is carried out at 80°C. After the precipitation is completed, it is aged at a constant temperature for 4 hours. After the aging, the precipitate is filtered and washed, dried in an oven at 60° C., and then calcined at 400° C. for 4 hours to prepare a FeZnNa catalyst.

[0018] 2. Put 1.85g of β molecular sieve in 50mL of 0.25mol / L NaOH aqueous solution, put it into a hydrothermal kettle lined with polytetrafluoroethylene, transfer it into an oven, and conduct hydrothermal treatment at 150°C for 21h. After the reaction was completed, the catalyst was taken out, washed, filtered and dried, and calci...

Embodiment 2

[0021] In this example, according to the molar ratio of Fe / Zn being 2:1 and the mass ratio of Na / (Fe+Zn) being 3%, the FeZnNa catalyst was prepared by the method in step 1 of Example 1. And after preparing the Naβ molecular sieve catalyst according to the method of step 2 of Example 1, the reaction of catalyzing synthesis gas to prepare light olefins was carried out according to the method of step 3 of Example 1, and the results are shown in Table 1.

Embodiment 3

[0023] In this example, the FeZnNa catalyst was prepared according to the method in Step 1 of Example 1. When preparing the Naβ molecular sieve catalyst, the concentration of the NaOH aqueous solution used was 0.5 mol / L, and other steps were the same as step 2 of Example 1. Then, according to the method in step 3 of Example 1, the reaction of preparing light olefins from catalytic synthesis gas was carried out, and the results are shown in Table 1.

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PUM

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Abstract

The invention discloses a method for preparing low-carbon olefins by catalyzing the conversion of synthesis gas. The method adopts a fixed-bed reactor, and the catalyst is loaded in the upper and lower stages. The upper stage is filled with FeZnNa catalyst, and the lower stage is filled with Naβ molecular sieve catalyst; Hydrogen reduces the FeZnNa catalyst, and then feeds synthesis gas for reaction. The preparation method of the catalyst used in the method of the present invention is simple, cheap, green and pollution-free. Compared with the traditional F-T synthesis, the catalyst is used to obviously improve the selectivity of low-carbon olefins, and at the same time in CH 4 In the case of no obvious increase in activity, C 5 + The product is cleaved. When tested under typical Fischer-Tropsch synthesis industrial conditions, the CO conversion rate is as high as 90%, and the low-carbon olefins (C 2 ＝ ~C 4 ＝ ) selectivity reaches about 50%, and has good industrial application prospect.

Description

technical field [0001] The invention belongs to the technical field of catalysis, in particular to a catalytic synthesis gas (CO+H 2 ) conversion method for preparing light olefins. Background technique [0002] At present, scholars have conducted extensive research on Fischer-Tropsch synthesis, but there are still many key technologies in product selectivity regulation that have not been broken through. How to break through the traditional ASF distribution restrictions and prepare products with a specific range of C atoms with high selectivity become a current research hotspot. [0003] Zhao et al. (Chem 2017,3,2,334-347) combined Na-Zn-Fe 5 C 2 Mixed with mesoporous HZSM-5 molecular sieve to catalyze the conversion of synthesis gas, but found that the products were biased towards aromatics rather than low-carbon olefins; Hadadzadeh et al. (Petrol Chem, 2010, 50(1):78-86) used alumina, molecular sieves and other carriers FeMn catalyst and H 2 After S post-treatment, it...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C1/04C07C11/04C07C11/06C07C11/08
CPCC07C1/044C07C2529/76C07C11/04C07C11/06C07C11/08Y02P20/52
Inventor 董文生侯屹峰李吉凡刘春玲宋喆
Owner SHAANXI NORMAL UNIV
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