生物质和废塑料混合热解协同特性研究

选取聚丙烯(PP)和竹屑作为废塑料与生物质的典型代表,在热重分析仪和固定床台架上研究了塑料掺混比例对混合热解失重特性、动力学机理、产物分布行为等特性的影响,并分析了混合热解时生物质和废塑料间的协同作用机制。结果表明,随着塑料掺混比例的增加,混合热解终止温度由501℃降低至471℃,主要热解温度区间缩短;混合热解所需活化能呈现先减小后增大的趋势,在塑料掺混比例为0.25时取得最小值。通过对比实验数据和理论数据发现,生物质与废塑料混合热解具有很强的协同作用:该协同作用降低了生物质反应所需能量,增加了废塑料反应所需能量,降低了混合热解过程的总活化能;此外,协同作用促进大分子挥发分转化为小分子气体,促进芳烃、烷烃等烃类生成,抑制CO_2、苯酚、羧酸、呋喃和酮类等含氧物质生成。

Synergistic effect during biomass and waste plastics co-pyrolysis

Polypropylene (PP) and bamboo were selected as typical representatives of waste plastics and biomass. And the biomass and plastic co-pyrolysis weight loss, kinetic mechanism and product distribution were studied by thermogravimetric analyzer and fixed-bed reactor. The synergistic mechanism between biomass and plastic during co-pyrolysis was discussed. As the ratio of plastic increases, the ending temperature of co-pyrolysis decreases from 501 to 471℃, while the main temperature range for co-pyrolysis is shortened. What's more, the total activation energy required for the co-pyrolysis decreases when the plastic ratio is below 0.25 and then increases. Comparing the experimental with theoretical data, it is found that the synergistic effect during biomass and waste plastics co-pyrolysis is obvious. Due to the synergistic effect, the total activation energy for co-pyrolysis is much lower than calculated value. In addition, the synergistic effect can promote the conversion of macromolecular volatiles into small-molecule gas, accelerate the generation of hydrocarbons like aromatics and alkanes, and inhibit the formation of oxygen-containing substances like CO₂, phenol, carboxylic acids, furans and ketones.