复合离子改性γ-Al_2O_3在合成气直接制二甲醚中的应用

Application of composite ion-modified γ-Al_2O_3 in direct synthesis of dimethyl ether from syngas

对γ-Al2O3进行了S2O82-、Ni2+复合离子改性,将改性后的γ-Al2O3用作合成气直接制二甲醚催化剂的甲醇脱水组分,制备出了CuZnAl/γ-Al2O3-S2O82--Ni2+双功能催化剂。在连续固定床高压反应器中,研究了改性条件对催化剂性能的影响。当(NH4)2S2O8溶液浓度15%、Ni(NO3)2溶液浓度1%,改性浸渍时间3h、浸渍温度80℃、焙烧温度450℃时,CuZnAl/γ-Al2O3-S2O82--Ni2+催化剂的催化效果最好,在260℃、3.2Mpa、1500h-1空速和n(H2)/n(CO)=2的反应条件下,CO转化率为80%,二甲醚选择性为52%。改性后的γ-Al2O3作为双功能催化剂中的甲醇脱水组分好于改性前。

γ-Al2O3 was modified with two ions S2O8^2- and Ni^2＋ together and used as the methanol dehydration component in the hybrid CuZnAl/γ-Al2O3-S2O8^2--Ni^2＋. for the direct synthesis of dimethyl ether from syngas. Effects of modification conditions on the performance of the catalysts were studied in a continuous high pressure fixed bed reactor. The CuZnAl/γ-Al2O3-S2O8^2--Ni^2＋ catalyst prepared using the γ-Al2O3 modified by impregnation with a （NH4）2S2O8 solution of 15% by mass and a Ni （NO3）2 solution of 1% by mass in sequence both for 3 hours at 80℃ and calcined at 450℃ showed the best catalytic performances, and it gave a selectivity to dimethyl ether of 52% with a conversion of cabon monoxide of 80% under 260℃, 3.2MPa and feed gas space velocity of 1500h^-1 with the H2/CO molar ratio of 2. The modified γ-Al2O3 demonstrated better dehydrating performance than the original.