The Pyrolysis And Kinetic Analysis Of Waste Black Fungus Chaff

Waste black fungus(Auricularia auricula)chaff refers to the residue of culture medium after receiving black fungus using straw,sawdust and other raw materials as substitutes for black fungus.It is the compound of black fungus mycelial residue and crude fiber with qualitative change of structure after enzymatic hydrolysis,which belongs to biomass energy.According to statistics,the annual production of fungus chaff of black fungus in China is about 4 million tons.In addition to about 30%of the fungus chaff being used as livestock feed and organic fertilizer,70%of the fungus chaff has not been properly utilized,which not only causes a waste of resources,but also causes environmental pollution.In this paper,thermogravimetric analysis(TGA)was carried on three kinds of waste black fungus chaff with different materials which include wood chips,cotton seed hells and straw,wheat,dry cow dung were mixed in a 3:2:5 ratio as substrates to study the pyrolysis characteristics.Firstly,the control variable method was adopted for gas atmosphere,grain diameter,heating rate three influence factors to explore its influence on fungus chaff pyrolysis process,and kinetic analysis.Secondly,chose Kissinger-Akahira-Sunose method,Flynn-Wall-Ozawa method,Kissinger method,three kinds of iso-conversion method to calculate the activation energy E,and compared with the calculated results and kinetic model established by the Coats-Redfern integral method.Finally,the activation energy,pre-exponential factor and optimal mechanism function were obtained to provide ideas and corresponding data basis for rational utilization of the waste black fungus chaff.The results show that the pyrolysis processes of the three kinds of fungus chaff are divided into four stages:dehydration stage,the slight weight reduction stage,the rapid pyrolysis stage and carbonization stage.The weight loss rate of fungus chaff is the highest during rapid pyrolysis.After the pyrolysis of the three kinds of fungus chaff,the residual amount of fungus chaff using wood chips as the substrate is the least,which was 9.182%.The reaction of fungus chaff in air atmosphere is more complex,and the weight loss rate is higher.The residual amount of fungus chaff in air atmosphere with the ratio of 3:2:5 between straw,wheat straw and dry cow dung is the least,which is 0.702%.The smaller the grain diameter is,the smaller the residual amount is,and the grain diameter has the greatest influence on the pyrolysis process of fungus chaff using cotton seed hells as substrate.With the increase of heating rate,the pyrolysis process shift to the high temperature region.Heating rate in the range of 10 to 20℃,the higher the heating rate,the lower the residual amount of the fungus chaff with wood chipst and cotton seed hulls after the pyrolysis process.The lower the heating rate,the lower the residual amount of the fungus chaff with the 3:2:5 ratio of straw,wheat straw and dry cow dung as the substrate.Contrast the calculated results obtained by the methods used in Kissinger-Akahira-Sunose method,Flynn-Wall-Ozawa method,Kissinger method and used in Coats-Redfern integral method of the three kinds of fungus chaff.The optimal mechanism function of the three kinds of fungus chaff was obtained as follows:G(α)=α2,and the pyrolysis mechanism followed the parabolic rule.The calculated activation energy was 161.20 kJ·mol-1,166.59 kJ·mol-1,respectively.157.62 kJ·mol-1,and the complexity of pyrolysis is the fungus chaff with the 3:2:5 ratio of straw,wheat straw and dry cow dung as the substrate>the fungus chaff with wood chips as the substrate>the fungus chaff with cotton seed hulls as the substrate.As for the fungus chaff with wood chips as the substrate,the heating rate has little effect on the activation energy.When the heating decreases,the activation energy tends to decrease slightly.