食用菌生产废弃物热反应机理与活化能

Pyrolysis Mechanism of Edible Mushroom Bran and Determination of Activation Energy

利用TG-FTIR联用分析仪对食用菌生产废弃物的热解特性进行了研究;并采用分布式活化能模型求解了主要热懈段的活化能,探讨了活化能随转化率的变化关系;利用FTIR结果分析了食用菌生产废弃物的热反应机理.研究结果表明;食用菌生产废弃物主要分三段热解;第一段热解在23100℃;失重率在12.33%14.36%左右;主要为C=O键的断裂和CO2的形成,伴随着少量的苯环从长链分子中断裂.第二失重段约在220390℃,失重率约为45.09%47.29%;主要为C=O键的断裂和CO2的形成、大量苯环从分子成分的长链脱离,同时伴有O-H键断裂、烷烃类的C-H键和取代苯的C-H键的断裂.第三失重段约在380800℃之间,这阶段失重率为15.01%15.34%,主要为C=O键断裂,且强度比第二段有所增加.主要热解段第二段的热解活化能在105165 kJ变化,呈先递增后减小的变化规律,在转化率0.7处达到最大值.

Pyrolysis characteristics of edible mushroom bran were investigated with thermogravimetry combining with Fourier-transform infrared spectroscopy(TG-FTIR) technique.The distributed activation energy model(DAEM) was used to calculate the activation energy.The effect of conversion rate on activation energy was discussed and pyrolysis mechanism of edible mushroom bran was analyzed.The results showed that the pyrolysis of edible mushroom bran has three stages:the first-stage was from the temperature of 20 to 110℃ with a weight loss of 12.33%~14.36%and breaking of C=O bond,formation of CO_2 and detachment of small amount benzene from main chain of organic compounds of edible mushroom bran was showed.The second-stage was from 220℃ to 400℃ with a weight loss of 45.09%~49.59%and breaking of C=O bond,formation of CO_2 and a great quantity benzene breaking away from backbones accompanied by cleavages of O-H、C-H from alkane and substituted benzene.The third stage was from 400 to 800℃ with a weight loss of 15.11%~15.34%and cleavage of C=0 bond was main thermal cracking reaction in the stage.The activation energy of second-stage pyrolysis was in the range of 105~165 kJ and first increase and then decrease with the maximum at conversion rate of 0.7.