升温速率对活化黄姜水解残渣动力参数的影响

EFFECT OF HEATING RATE ON KINETICS PARAMETERS TO ACTIVATE THE RESIDUES FROM THE HYDROLYZED DIOSCOREA ZINGIBERENSIS

黄姜水解残渣是黄姜皂素生产中的固体废物,主要成分为木质素,是一种制备活性炭的优质材料.TG-DTG分析升温速率对活化过程有较明显的影响,运用简化模型Freeman-Carroll微分法和Ozawa及Kissinger积分法考察升温速率对活化黄姜水解残渣动力参数的影响,对集成优化活化过程有重要的指导意义.随升温速率的上升,活化能E与指前因子A基本上呈减小趋势,且E与A符合有关学者提出的“动力学补偿效应”;在同一升温速率下,动力学曲线有两个线性区域,温度较低时,挥发物的析出主要受化学控制,温度较高时,活化过程主要受扩散控制;用不同速率得出的活化能可初步判断原料的活化难易程度.

The residues from the hydrolyzed dioscorea zingiberensis are a kind of solid wastes,whose main component is iignin that can be prepared into activated carbon as an excellent raw material. They show outstanding influence for heating rate on the process of activation by TG-DTG analysis. Simple differential method of Freeman-Carroll and integral methods of Ozawa or Kissinger are applied to determine the effect of heating rate on kinetics parameters,it will be very important to guide and optimize activated processes. As the heating rate increases, activated energy E and pre-exponential or frequency factor A decrease basically, which is accordant with the proposal that ＂compensatory effect for kinetics＂ put forward by other professors. At the same heating rate, there may be two linear regions ：a chemical-controlling region at lower temperature, and a transport-limited region at higher temperatures. The apparent activation energy in this study probably represents the energy for the rate-controlling step and includes the effect of any transport limitations ,and reflects the ability of raw material to be activated.