黄豆秆两级连续热解特性研究

RESEARCH ON TWO-STEP CONSECUTIVE PYROLYSIS CHARACTERISTICS OF SOYBEAN STALKS

为优化生物质热解过程,获得更高品质的生物油,利用热裂解仪-气相色谱/质谱联用仪(Py-GC/MS)对黄豆秆进行两级连续热解研究,并利用热重分析仪(TG)研究黄豆秆在不同升温速率下的失重特性。结果表明:黄豆秆热失重过程主要分为4个阶段,其中200~450℃为主要的热解区间,此阶段内基本完成半纤维素和纤维素的热解。与单级热解相比,两级连续热解能减少组分间的相互作用和产物的二次反应,进而提高总可冷凝挥发性有机产物的产率。250℃和300℃时能提高各类产物的产率,尤其可显著提高酚类和芳香烃类等源于木质素的产物产率;而400℃和450℃时主要提高酸类、呋喃类和环戊烯酮类等源于半纤维素和纤维素的产物的含量和产率,有利于提高生物油的品质和分离利用。

A new form of pyrolysis called the two-step consecutive pyrolysis was investigated by using pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS)with soybean stalk to optimize the biomass pyrolysis and obtain higher quality bio-oil.The thermal gravimetric characteristic of soybean stalk was also studied at heating rates of 10 to 30°C/min by the use of thermogravimetric analyzer(TG).The results indicate that the thermal decomposition process is composed of four stages,and the second stage of which from 200℃to 450℃has the maximum weight loss because of the decomposition of cellulose and hemicelluloses completely.Compared with the control group of single step pyrolysis,the two-step consecutive pyrolysis can improve the yield of total volatile organic products ascribed to fewer interactions among the three components and secondary reactions in the pyrolysis process.The yields of each kinds of products are enhanced at T1 of 250 and 300℃,and especially the yields of lignin derivatives(phenols and aromatic hydrocarbons)are remarkably improved.The yields and contents of holocellulose derivatives(acids,furans and cyclopentenones)and are both improved at T1 of 400 and 450℃,thus improving the quality and utilization of bio-oil.