Effect of Variable Heating Rate on Pyrolysis Process and Product Characteristics of Corn Stalk

The influence of heating rate on slow pyrolysis was explored. The corn stalks were tested via two types of variable heating rate comparing with three types of constant heating rate. The products such as char, pyrolysis bio-oil and non-condensable gases at different heating rates were also detected. The pyrolysis by decreasing heating rate resulted in 29.82% char and 27.49% non-condensable gases. While the increasing heating rate caused higher bio-oil yield which was not benefit to the production of char and pyrolysis gas. Thermo-gravimetric analysis of the raw materials showed that variable heating rate significantly changed the weight loss during pyrolysis process. It was found that CO and CO2 were released earlier than CH4 and H2 by performing gas chromatography test. In the higher temperature zone, the concentration of H2 was increased. The analysis of the main components in bio-oil confirmed that less macromolecular organic matter content was detected after pyrolysis by decreasing heating rate. While the increasing heating rate produced more polycyclic aromatic hydrocarbons. The concept of variable heating rate was presented. It was found that the pyrolysis by decreasing heating rate not only made sure the yields of chars and pyrolysis gas, but also increased the char yield by 4.49%, and deduced the bio-oil yield by 4.51% and this process was more to the benefit of poly-co-production with char and pyrolysis gas as the main products. This concept would provide new ideas for the project of biomass pyrolysis. © 2018, Chinese Society of Agricultural Machinery. All right reserved.