用于合成气制高值产物的InZrOx 氧化物制备及性能

Preparation and properties of InZrOx oxides for conversion of syngas to high-value products

摘要:

以四水合硝酸铟和五水合硝酸锆为原料，通过共沉淀法和水热法制备InZrOx氧化物，并在最佳制备条件下探究煅烧温度对合成氧化物的影响，与SAPO-34分子筛结合为双功能催化剂用于用于合成气催化转化制高值产物。采用XRD、SEM-EDS、HRTEM、XPS和BET对氧化物的织构性质、晶体结构、形貌特征及表面电荷进行表征与测试，并在固定床反应器中系统研究了空速、原料气氢碳比（物质的量）、氧化物与分子筛质量比、反应温度及反应压力对催化效果的影响规律。结果表明，共沉淀法得到的氧化物在各方面表现均优于水热法，最佳煅烧温度为550 ℃。在空速为2000 mL/(gcat·h)、原料气氢碳比（物质的量）为3：1、m(InZrOx)：m(SAPO-34)=1：1、400 ℃、3 MPa的反应条件下，CO转化率为67.58%，高值产物选择性为70.81%[C2-4=选择性为37.74%、液体燃料（C5+）烃类选择性为33.07%]，C2-4=收率可达23.98%，副产物CO2选择性仅为5.99%。

Abstract:

InZrOx oxide was prepared by co-precipitation and hydrothermal methods using indium nitrate tetrahydrate and zirconium nitrate pentahydrate as raw materials, and the effect of calcination temperature on the synthesized oxides was investigated under optimal preparation conditions, and combined with SAPO-34 molecular sieve as a bifunctional catalyst for the catalytic conversion of syngas to high-value products. The texture properties, crystal structure, morphology features, and surface charge of the oxides were characterized by XRD, SEM-EDS, HRTEM, XPS and BET. And the factors affecting the catalytic effect, including pace velocity, hydrogen-carbon mole ratio of feed gas, mass ratio of oxide to molecular sieve, reaction temperature, and reaction pressure, were systematically studied in a fixed bed reactor. The results showed that the oxides obtained by co-precipitation performed better than the hydrothermal method in all aspects, and the optimum calcination temperature was 550 °C.The reaction conditions were optimized as follows: space velocity 2000 mL/(gcat·h), hydrogen-carbon mole ratio 3:1, m(InZrOx):m(SAPO-34)=1:1, 400 °C, and 3 MPa. Under the optimized conditions, the conversion of CO was 67.58%, the selectivity of high-value products was 70.81%(including the selectivity of C2-4= was 37.74%, the selectivity of C5+ was 37.74%), the yield of light olefins reached 23.98%, and the selectivity of by-product CO2 was only 5.99%.