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以Beta分子筛为核、Y型分子筛为壳层的多级孔复合分子筛(BFZ)作为甲醇脱水催化剂用于固定床中合成气一步法制备二甲醚,并与纯Y型分子筛进行了比较,研究了二甲醚合成催化反应活性与甲醇脱水催化剂孔道结构和酸性之间的关系。结果表明,复合分子筛HBFZ具有中等强度的酸性和中孔孔道结构,有利于提高合成气制备二甲醚的催化反应活性。二甲醚直接合成催化剂由工业CuO/ZnO/Al2O3催化剂(CZA)与分子筛(HBFZ、HY)采用机械混合方法制备;催化评价结果显示,CZA/HBFZ比CZA/HY具有更优的催化活性和稳定性。在250℃,5.0 MPa和1 500 h-1的反应条件下,CZA/HBFZ催化剂上CO的转化率和DME的选择性分别达到94.2%和67.9%。
The multi-stage pore composite molecular sieve (BFZ) with zeolite Beta as the core and the Y-type molecular sieve as the shell was used as methanol dehydration catalyst for the one-step synthesis of dimethyl ether in the fixed bed synthesis gas and compared with the pure Y-type molecular sieve The relationship between the catalytic activity of dimethyl ether synthesis and the pore structure and acidity of methanol dehydration catalyst was studied. The results show that the composite zeolite HBFZ has moderate acidity and mesoporous pore structure, which is beneficial to improve the catalytic activity of the synthesis of dimethyl ether. The direct synthesis catalyst of DME was prepared by the mechanical mixing of industrial CuO / ZnO / Al2O3 catalyst (CZA) and molecular sieve (HBFZ, HY). The catalytic evaluation showed that CZA / HBFZ had better catalytic activity and stability than CZA / Sex. Under the reaction conditions of 250 ℃, 5.0 MPa and 1 500 h-1, the conversion of CO and the selectivity of DME on CZA / HBFZ catalyst reached 94.2% and 67.9%, respectively.