摘要
在反应温度950～1 200℃,升温速度20℃/min的实验条件下,用热重分析仪对炭催化剂作用下CO_2气化和CH_4-CO_2重整过程中炭催化剂失重进行了研究。结果表明,在炭催化剂-CO_2气化过程中,随着CO_2流量的增加和反应温度的提高,炭催化剂的失重率明显增加,CO_2流量和反应温度是造成炭催化剂失重的重要原因。在炭催化CH_4-CO_2重整过程中,随着CO_2/CH_4比值的增加炭催化剂质量先增加后减少,表明炭催化剂的失重率可以通过CO_2/CH_4来调节;而随反应温度升高,炭催化剂质量变化表现为低温(<1 100℃)单阶段和高温(>1100℃)双阶段两种类型,即在反应温度低于1 100℃时,炭催化剂失重反应主要由化学反应过程控制,CH_4裂解碳沉积和CO_2的气化消碳很快达到平衡,炭催化剂失重宏观上表现为维持恒定的单一阶段;当反应温度高于1 100℃后,炭催化剂的失重表现为双阶段,开始的第一阶段,主要受化学反应过程控制,炭催化剂急剧失重,然后逐步过渡到扩散过程控制的第二阶段,失重率逐渐趋于平缓;炭催化CH_4-CO_2重整过程中,反应温度和CO_2/CH_4比是导致炭催化剂失重的主要因素。
The mass-loss characteristic of carbonaceous catalyst in the char- CO2 gasification and CH4-CO2 reforming reaction was investigated using thermogravimetric analyzer with the heating rate of 20 ℃/min under the condition of 950--1 200℃. The results showed that the mass-loss of carbonaceous catalyst increased obviously in char- CO2 gasification with increasing of the reaction temperature and flow of CO2. In the CH4-CO2 reforming reaction catalyzed by carbonaceous catalyst, the mass of carbonaceous catalyst increased at the early stage and decreased at the later stage with the increasing of the CO2/CH4 ratio, which indicated that the mass change of carbonaceous catalyst in CH4-CO2 reforming could be adjusted by adjusting the ratio of CO2 to CH4. The mass-loss behavior of carbonaceous catalyst in CH4-CO2 reforming could be divided into two types： low temperature single stage （1 100℃） and high temperature double stage （1 100 ℃）. When the temperature was below 1 100℃, the mass-loss reaction of carbonaceous catalyst was controlled by chemical reaction and the quick equilibrium between carbon deposition caused by methane decomposition and carbon elimination by CO2 gasification, the mass-loss rate of carbonaceous catalyst was lower. When the reaction temperature was beyond 1 100℃, the mass change of carbonaceous catalyst exhibited the double stage, the mass of carbonaceous catalyst lost quickly at the early stage which was controlled by chemical reaction, and then the mass-loss was stable stage which was controlled by diffusion. The results showed that the reaction temperature, CO2 flow and the ratio of CO2 to CH4 were the most important influence factors to the mass-loss of the carbonaceous catalyst in CH4-CO2 reforming.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
2009年第1期36-40,共5页
Chemical Reaction Engineering and Technology
基金
国家重点基础研究发展计划(2005CB221202)
山西省自然科学基金(20051020)
关键词
炭催化剂
甲烷二氧化碳重整
催化剂失重
热失重分析
carbonaceous catalyst
methane-carbon dioxide reforming
catalyst mass-loss
themogravimetric analysis
