典型高阶煤的催化气化特性研究

Catalytic gasification property of high rank coal

以碱金属盐(KNO3)、碱土金属盐(Ca(NO3)2)以及过度金属盐(Fe(NO3)3)为典型的催化剂,研究了我国典型高阶煤——奉节煤的催化气化行为。催化剂与煤样通过浸渍方法混合,而后在1 000℃进行热解制焦,然后对所得焦样采用热重分析仪进行非等温CO2气化,并采用收缩核模型对气化机理进行了探讨。研究发现:奉节无烟煤焦本身很难气化,最大气化速率出现在1 100℃,然而随着催化剂的加入,其气化温度显著降低(100℃左右),最大气化速率明显增大,催化作用随催化剂添加量的增加而加强,KNO3的低温催化作用较强,而Ca(NO3)2和Fe(NO3)3在高温下有较强的催化作用;煤焦的催化气化过程分为过渡区和动力区,且随着催化剂的加入,动力区的起始温度大幅度降低;催化系数不仅与温度有密切的关系,与煤种类型以及催化剂的添加量都有着紧密的联系。

The gasification behavior of Fengjie coal was investigated with KNO3,Ca（NO3）2 and Fe（NO3）3 as catalyst.The catalyst was mixed with Fengjie coal through immersion method,then the coal sample was pretreated at 1 000 ℃ in inert atmosphere,after that,the non-isothermal gasification of resultant char was performed in thermogravimetric analyzer with CO2 as gasifying agent,and the kinetics of Fengjie coal char gasification was analyzed using shrinking core mode.It was found that the gasification for Fengjie coal was very difficult with the maximum gasification rate at 1 100 ℃;however,it was improved greatly as the temperature was lowered obviously（about 100 ℃）,the maximum gasification rate increased with the catalyst adding,and the catalytic effect was strengthened with the catalyst amount increasing.But the catalytic is different with catalyst variant,and KNO3 is better for low temperature gasification,while the catalytic of Ca（NO3）2 and Fe（NO3）3 are much stronger at higher temperatures.The gasification can be divided into transition region and kinetics region.With the catalyst adding,the initial and final temperature of kinetics region largely decreased.Finally,the catalytic coefficient has close relationship with temperature,catalyst type and adding amount.