生物质焦油热裂解动力学参数实验研究

Experimental study on kinetic parameters of thermal cracking of biomass tar

基于进样过程中焦油蒸发的不稳定性以及反应温度的测定和控制难度,设计了移动床焦油进样系统,使用样品槽携带焦油进入具有线性温度分布的炉膛空间,以样品槽的运动进样代替焦油流动进样,以获得稳定的焦油蒸发进样和更容易控制的反应温度。在此基础上,研究了不同进样速率下的焦油热裂解及其动力学特性。结果表明,在573～1 123 K,焦油的裂解率随温度的升高而加速升高,并在1 123 K时达到58%的裂解率;焦油热裂解遵循一级动力学反应,其平均活化能为39.5 kJ/mol,指前因子为1.58 min-1。

For the reason of the unstable evaporation in the tar sampling process and the difficulty of measuring and controlling reaction temperature,a moving bed as the tar sample introduction system was designed.A sample tray carrying tar was moved into the furnace with linear temperature distribution of the entrance zone.The movement of the tray instead of that of the tar,makes the tar sample introduction process more stable and the temperature easer to control.On this basis,tar cracking process and kinetic characteristics with the different sample introduction rate were studied.The results indicate the tar cracking rate is accelerated with increasing temperature at 573~1 123 K.The tar cracking rate reaches 58% at 1 123 K.The tar thermal cracking reaction is a first order reaction.On average,the activation energy is 39.5 kJ/mol and the pre-exponential factor is 1.58 min-1.