预处理条件对Fe-Mn催化剂催化CO加氢合成低碳烯烃性能的影响  

Effects of Pretreatment Conditions for Iron-Manganese Catalyst on Synthesis of Light Olefins Through CO Hydrogenation

作　　者：张建利[1] 赵天生[1] 范素兵[1] 李文怀[2] 孙予罕[2] 

机构地区：[1]宁夏大学能源化工自治区重点实验室,宁夏银川750021 [2]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001

出　　处：《石油化工》2010年第12期1332-1336,共5页Petrochemical Technology

基　　金：中国石油天然气股份有限公司项目(W050509-03-02);宁夏自然科学基金项目(NZ1010);新世纪优秀人才支持计划项目(NCET-08-0872)

摘　　要：制备了一系列Fe-Mn催化剂,考察了预处理条件对其催化CO加氢合成低碳烯烃性能的影响。实验结果表明,用CO处理的催化剂较用H_2处理的催化剂具有较高的烯烃选择性;在CO气氛、300℃下还原4h的催化剂上,产物C_(2～4)烃中烯烃与烷烃的质量比可达5.88;碳化温度升高,重质烃含量增加;但在CO气氛、400℃下还原4h的催化剂上,产物中重质烃含量有所下降。XRD和XPS表征结果显示,用CO处理的催化剂中有碳化物生成,且高温、CO处理的催化剂表面有大量的碳化物生成;CO_2(CO)-TPD表征结果显示,碳化过程增强了催化剂的表面碱性,增强了CO的吸附能力,相对加氧能力减弱,烯烃选择性提高,促进了链增长。但同时CO吸附能力的增强,促进了CO高温预处理下的碳沉积,进而抑制了重质烃的生成。Effects of pretreatment conditions for the iron-manganese catalysts on synthesis of light olefins through CO hydrogenation were investigated. It was found that the CO and H2/CO pretreated catalysts showed higher olefin selectivity than only H2 pretreated that. The mass ratio of olefins to paraffins in the C2-4 products reached 5.88 when the catalyst was pretreated with CO at 300 ℃ for 4 h. The heavy hydrocarbon content increased with rise of the carbonization temperature but decreased when the catalyst was pretreated with CO at 400℃. XRD and XPS characterizations indicated that the CO pretreatment led to formation of iron carbide, and carbon deposition on the catalysts was found when the pretreatment was carried out at high temperature. CO2 （CO）-TPD result showed that the formation of carbide species could enhance the surface basicity which favored the CO adsorption. The enhancement inhibited hydrogenation of the olefins so increased the olefin selectivity and promoted the chain propagation. The enhanced CO adsorption could promote the formation of graphitic carbon when the catalysts were pretreated with CO at high temperature, which could suppress the formation of the heavy hydrocarbons.

关 键 词：铁锰催化剂 一氧化碳加氢 低碳烯烃 预处理 碳化 

分 类 号：TQ221.1[化学工程—有机化工]