硬木热解过程中颗粒内部二次反应的数值研究 Ⅰ.单颗粒热解模型的构建

NUMERICAL SIMULATION OF SECONDARY REACTIONS INSIDE HARDWOOD PARTICLE DURING PYROLYSIS Ⅰ. CONSTRUCTION OF SINGLE PARTICLE PYROLYSIS MODEL

为了研究生物质 (硬木 )热解过程中颗粒内部的二次反应 ,弥补常规实验研究在该领域内的不足 ,构建合适的数学模型进行数值模拟是一个很好的途径。本文介绍了硬木单颗粒热解综合模型的构建方法。针对所研究的问题 ,模型中细致考虑了包含一次焦油二次裂解的生物质热解动力学过程。为了准确描述热解产物在热解颗粒内部的传递和二次反应过程 ,模型包含了对热解过程中颗粒内部各种气相产物在孔隙率不断变化的生物质颗粒内的生成、消耗、积累以及在压力驱动下的输运等行为的描述。模型参数的选取尽可能真实地模拟了实际过程 ,引入转化率或温度对涉及到的各种物理性质参数进行了修正。构建的模型在理论上较全面地描述了单颗粒生物质热解的复杂过程 。

The experimental research on secondary reactions inside particle during hardwood pyrolysis is greatly limited by the level of up to date measure technology, while numerical simulation based on comprehensive mathematical model provides an excellent tool in this field The construction of a single particle pyrolysis model is introduced in this paper The comprehensive model includes the kinetic sub model of secondary reactions of primary pyrolytic product To fulfill the exploration of secondary reactions inside particle, the model also carefully includes the processes of the yielding, consuming, accumulating or escaping of the major pyrolysis products in developing porous matrix of reacting hardwood The parameters of the model are also selected carefully to simulate the real situation; the conversion rate and temperature are introduced to correct the involved physical properties during pyrolysis This comprehensive model is capable of simulating the complex pyrolysis process in enough detail to do further research on secondary reaction