重油残渣焦水蒸气气化反应特性的研究

采用常压热重分析仪,研究了重油残渣焦的水蒸气气化反应性,主要考察了热解温度、升温速率、停留时间及气化反应温度、气化剂分压对重油残渣焦水蒸气气化反应的影响,并借助XRD对残渣焦进行了分析表征。结果表明,气化温度950℃,60%水蒸气分压条件下,快速热解焦比慢速热解焦的气化反应性高;随制焦温度(500~900℃)的提高及停留时间的延长,焦的气化反应性降低。气化温度是影响重油残渣焦气化反应的主要因素,在900~1 050℃,温度每提高50℃,重油残渣焦气化反应时间几乎减半;随着水蒸气分压的提高,气化反应速率增加,但当气化剂分压高于60% 时,其对气化反应影响较小。采用均相模型和缩核模型对重油残渣焦气化曲线进行模拟,结果发现,缩核模型模拟相关性较好,其活化能为195.0 kJ/mol,指前因子A₀为2.6×10⁷min^-1。

Steam gasification reactivity of chars from heavy oil residue

The gasification reactivity of heavy oil residue chars in steam atmosphere was studied by Thermal Gravimetric Analyzer (TGA) and micro-crystalite of the char was analyzed by X-ray diffraction (XRD). The effects of heating rate, pyrolysis temperature, residence time, gasification temperature and the partial pressure of steam were evaluated separately. The results show that at 950℃ and 60% partial steam pressure, gasification reactivity of chars formed at slow heating rate is lower than that formed at fast heating rate. With increasing pyrolysis temperature and residence time, the reactivity of char decreases. Gasification temperature is the main factor influencing the gasification rate. From 900 to 1 050℃ the gasification time is almost halved with the increasing temperature of 50℃. The increasing of steam partial pressure can improve the gasification rates greatly until the partial pressure comes to 60%, and after that it has no significant effect. The homogeneous model and the shrinking core model were used to characterize the gasification kinetic parameters. The later model is better and the apparent activation energy is 195.0 kJ/mol, the preexponentiol factor A₀ is 2.6×10⁷min^-1.