阴燃是一种针对高含水有机固废的低能耗处置技术,针对剩米饭开展自维持阴燃试验,以期为餐厨垃圾阴燃处置的工业化应用和相关尾气净化装置的开发提供技术参数支撑。研究了砂料比、点火温度、达西流速等参数对剩米饭减重效果和阴燃烟气各组分浓度的影响作用。结果表明,淀粉类餐厨的热解焦在500℃以上才能发生氧化反应。为保证淀粉类餐厨能在较低能耗工况下实现自维持阴燃处置,需保证阴燃体系系统低位热值大于0.72MJ/kg。对于系统低位热值稍低于此数值的混合物料,可通过提高点火温度和增大达西流速等助燃措施实现自维持阴燃。由于米饭高挥发分特性,阴燃体系中底部物料挥发分会在低温沙盖层区域部分冷凝,故阴燃处置末期原本不含可燃有机质的沙盖层会出现剧烈氧化放热。砂料比过高或过低均不利于剩米饭的阴燃处置;适当提高点火温度和达西流速均会增强大米阴燃处置效果;对于含水率60%的湿米饭,大米与石英砂质量比为4,达西流速为4cm/s、点火温度为350℃时处置效果最好。阴燃反应全过程内烟气中CO2、CO和VOCs浓度均呈先增加、再平稳、后下降的变化趋势。调控阴燃试验参数,自维持传播段CO2体积分数在6.75%~9.41%,CO体积分数在1.37%~2.51%,VOCs体积分数在109×10-6~251×10-6。湿米饭含水率越高,实现自维持阴燃所需最小达西流速越高;达西流速提高至8cm/s,最高能实现75%含水率淀粉类餐厨的处置。

Smoldering is a low-energy disposal technology for high-water organic solid waste, and self-sustaining smoldering experimentsare carried out for leftover rice to provide technical parameter support for the industrial application of food waste smoldering disposal andthe development of related tail gas purification devices. The effects of parameters such as abrasive ratio, ignition temperature and Darcyflow rate on the weight loss effect of leftover rice and the concentration of components of smoldering flue gas were experimentally studied.The results show that the oxidation reaction can only occur when the pyrolysis coke of starch based kitchens is above 500 ℃ . In order toensure that starchy kitchens can achieve self-sustaining smoldering disposal under low energy consumption conditions, it is necessary toensure that the low calorific value of the smoldering system is greater than 0.72 MJ/ kg. For mixed materials with a low calorific value of thesystem slightly below this value, self-sustaining smoldering can be achieved through combustion support measures such as increasing theignition temperature and the Darcy flow rate. Due to the high volatile content characteristics of rice, the volatiles of the bottom material inthe smoldering system will partially condense in the area of the low-temperature sand cover layer, so the sand cover layer that originallydoes not contain combustible organic matter will be violatively oxidized and exothermic at the end of smoldering disposal. Too high or toolow abrasive ratio will be detrimental to the smoldering disposal of leftover rice. The soldering disposal effect of rice will be enhanced byincreasing the ignition temperature and Darcy flow rate. For wet rice with a moisture content of 60%, the disposal effect is best when theDarcy flow rate is 4 cm/ s and the ignition temperature is 350 ℃ , the mass ratio of rice to quartz sand is 4. During the entire process ofsmoldering reaction, the concentrations of CO2, CO and VOCs in flue gas show a trend of first increasing, then stabilizing, and then decreasing. The CO2 concentration in the self-sustaining propagation section fluctuates between 6.75%-9.41%, CO changes in the range of1.37%-2.51%, and VOCs changes between 109×10-6 -251×10-6 by adjusting the experimental parameters of smoldering. The higherthe moisture content of wet rice is,the higher the minimum Darcy flow rate required to achieve self-sustaining smoldering is. The Darcyflow rate is increased to 8 cm/ s, which can achieve up to 75% moisture content starch kitchen disposal.

0 引言

1 试验

   1.1 试验材料

   1.2 试验装置

   1.3 试验步骤

   1.4 数据处理

2 结果分析与讨论

   2.1 样品热重特性

   2.2 干大米阴燃试验

   2.3 湿米饭阴燃试验

3 结论