食用菌废菌棒热解的产物分布与机理解析

Pyrolysis product distribution and mechanism analysis of edible fungi residue

我国食用菌废菌棒产生量大,利用率低,对环境污染严重,需要妥善处理。为制备高品质能源,在500～800℃温度范围内快速热解废菌棒,分析产物特征,解析热解机理。热解温度从500℃上升到800℃时,废菌棒的热解气质量分数从18.44%上升到50.45%,焦油的质量分数从49.06%下降到23.72%,生物炭的质量分数维持在30%左右,废菌棒的质量减量化率超过2/3;同时,热解气中H_2、CO、CH_4含量均有上升,CO_2含量下降;焦油组分向更稳定的苯系物转变;生物炭炭化效果增强。研究结果表明,700℃为最佳热解温度,经过120 s即可反应完全。高温可以破坏羟基的结构,使其发生脱氢反应,碳氢键较早断裂,伯碳和仲碳大量裂解并迁移至焦油和热解气中,羰基在高温下迅速断链。

In China,edible fungi residue needs to be properly and urgently disposed because of its tremendous amount,low utilization and serious pollution.In order to obtain high-quality energy,the edible fungi residue was treated by a fast pyrolysis at the temperature range from 500°C to 800°C,and the product characteristics and pyrolysis mechanisms were analyzed.As the pyrolysis temperature rose from 500°C to 800°C,the mass ratio of pyrolysis gas to edible fungi residue increased from 18.44%to 50.45%,while that of tar decreased from 49.06%to 23.72%,and that of biochar remained at about 30%.The mass reduction ratio of edible fungi residue exceeded 2/3.The contents of H2,CO and CH4 in pyrolysis gas increased,while CO2 content decreased.The main components of tar converted to more stable benzene homologues.And the carbonization effect of the biochar was strengthened.The results showed that the optimal pyrolysis temperature was 700℃,and the pyrolysis reaction could complete within 120 s.High pyrolysis temperature could destroy the hydroxyl structure,the dehydrogenation reactions occurred,then the hydrocarbon bond broke earlier,the primary and secondary carbons cracked largely and migrated into tar and pyrolysis gas,the bonds in the carbonyl groups will be rapidly disintegrated.