Vapor-phase transport (VPT) modification of ZSM-5/SiC foam catalyst using TPAOH vapor to improve the methanol-to-propylene (MTP) reaction
Vapor-phase transport (VPT) modification of ZSM-5/SiC foam catalyst using TPAOH vapor to improve the methanol-to-propylene (MTP) reaction
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DOI：
10.1016/j.apcata.2017.07.036
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发表时间：
2017-09-05
影响因子：
5.5
通讯作者：
Zhang, Jinsong
中科院分区：
文献类型：
--
作者：
Jiao, Yilai;Fan, Xiaolei;Zhang, Jinsong
在气相中引入四丙基氢氧化铵（TPAOH），对结构化ZSM-5/SiC泡沫（ZSM-5/SiC foam）催化剂进行了气相传输（VPT）改性。0.5M TPAOH的最佳前体浓度可以有效地将无定形铝硅酸盐粘合剂转化为具有改进的晶体内中孔、纳米尺寸晶体（约100 μ m）和纳米尺寸晶体（约100 μ m）的沸石相。100 nm）、高浓度的酸性中心（83 mmol g（-1））以及高的相对酸度值（0.7）。结合宏观SiC泡沫的固有特性，如低压降和高热导率（773 K时为14 W m（-1）K-1），TPAOH VPT改性的ZSM-5/SiC泡沫催化剂在催化甲醇制丙烯（MTP）反应中表现出优异的活性，超过了现有的多级ZSM-5整体式催化剂。该催化剂表现出延长的活性为ca。970 h（> 95%甲醇转化率），丙烯选择性高（> 45%）。焦炭的形成被显著地延迟（约。2.1 x 10（-2）重量% h（-1）），这是由于所开发的结构化催化剂内的增强的传输现象。
Tetrapropylammonium hydroxide (TPAOH) was introduced in the vapor phase to perform the vapor-phase transport (VPT) modification of the structured ZSM-5 supported on SiC foam (ZSM-5/SiC foam) catalyst. An optimum precursor concentration of 0.5 M TPAOH could effectively convert the amorphous aluminosilicate binder to the zeolitic phase with improved intracrystal mesopores, nanosized crystals (ca. 100 nm), high concentration of acidity sites (83 mmol g(-1)) as well as a high value of the relative acidity (0.7). Combined with the intrinsic property of macroscopic SiC foams such as the low pressure drop and the high thermal conductivity (14 W m(-1) K-1 at 773 K), TPAOH VPT modified ZSM-5/SiC foam catalyst demonstrated an excellent activity in the catalytic methanol-to-propylene (MTP) reaction, surpassing the state-of-the-art hierarchal ZSM-5 monolith catalyst. The catalyst showed an extended activity for ca. 970 h (> 95% methanol conversion) with the high selectivity to the propylene (> 45%). The coke formation was significantly retarded (ca. 2.1 x 10(-2) wt.% h(-1)) due to the enhanced transport phenomena within the developed structured catalyst.