Kinetics of coke formation in the dimethyl ether-to-olefins process over SAPO-34 catalyst
Kinetics of coke formation in the dimethyl ether-to-olefins process over SAPO-34 catalyst
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SAPO-34 催化剂上二甲醚制烯烃过程中焦炭形成的动力学
DOI：
10.1016/j.cej.2017.05.158
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发表时间：
2017-10-15
影响因子：
15.1
通讯作者：
Zeng, Penghui
中科院分区：
文献类型：
--
作者：
Gao, Yuli;Chen, Sheng-Li;Zeng, Penghui
采用热重（TG）反应器研究了SAPO-34催化剂上二甲醚（DME）转化制低碳烯烃过程中的结焦动力学。在升温速率为4K/min ~ 10 K/min、DME分压为40.53kPa ~ 101.325kPa的条件下进行了焦炭生成实验。考察了反应温度、二甲醚分压和催化剂积炭量对结焦速率的影响。结果表明，反应温度和二甲醚分压越高，结焦速率越大。在二甲醚制烯烃（DTO）反应的初期，结焦速率随焦炭含量的增加而增加，表明该反应为自催化反应。提出了催化剂结焦的机理，并建立了结焦速率与二甲醚分压、反应温度和催化剂结焦量之间的动力学方程。DTO反应的积炭活化能为99 kJ/mol，DME在催化剂表面吸附的活化能为49 kJ/mol。(C)2017爱思唯尔B. V.保留所有权利。
A kinetic of coke formation during dimethyl ether (DME) conversion to light olefins over SAPO-34 was studied by the use of a thermogravimetry (TG) reactor. Coke formation experiments were conducted at the heating rate from 4 K/min to 10 K/min and DME partial pressure between 40.53 kPa and 101.325 kPa. The effects of reaction temperature, DME partial pressure and coke content of catalyst on coking rate were investigated. The results showed that high reaction temperature and DME partial pressure led to high coking rate. The coking rate increased with coke content during the early stage of the DME to olefins (DTO) reaction, indicating that the coking reaction was autocatalytic reaction. A mechanism was proposed for the coke formation and a kinetic equation was established to correlate the rate of coke formation with DME partial pressure, reaction temperature and coke content of catalyst. The activation energies of coke formation and adsorption of DME onto the active sites of catalyst surface in DTO reaction were found to be 99 kJ/mol and 49 kJ/mol, respectively. (C) 2017 Elsevier B.V. All rights reserved.