Pyrolysis Processes And Products Characteristics Of Rapeseed Meal

Pyrolysis technology can converse the energy contained in biomass into energy products by the greatest extent, that is currently a hot research spot in borne and abroad. The characteristic of pyrolysis processes and products yield of rapeseed meal with electric heating were investigated in this paper. The characteristic of pyrolysis processes was verified by TGA and a comparative study of microwave heating was carried out.The results showed that the pyrolysis processes of rapeseed meal were divided into four stages:evaporation of water, the pyrolysis of hemicellulose, the pyrolysis of cellulose and lignin, and the carbonization of lignin at lower heating rate. When heating rate was higher, a continuous pyrolysis process was performed accorded with TGA analysis.Gas and liquid products were mainly isolated in 200-500℃that were mainly from pyrolysis processes of hemicellulose and cellulose. The higher the reaction temperature be, the higher the products yield be. The dQ/dt-T and dV/dt-T curve showed the tendency of decreased first and ascend later. Pyrolysis processes of hemicellulose and cellulose were achieved under different temperature interval at lower heating rate that had different products yield characteristic. The reasonable heating rates were 4-6℃/min for the pyrolysis of rapeseed meal.The higher reaction temperature and the lower heating rate can attain higher utilization value of flammable gas. The volumetric fraction, maximum density and heat-value of produced flammable gas were 70%,0.86 kg. m-3 and 35726.46 kJ. m-3, respectively. There were higher content of gasoline, diesel and crude oil in liquid products. It also showed that the lower the heating rate, the higher the calorific value of pyrolysis residues.The reaction completed quickly and the rising rate kept constant in temperature range of 200-400℃and 500-600℃with microwave heating of the rapeseed meal. Gas and liquid products were mainly isolated in 100-400℃with microwave heating Cellulose and lignin had higher gas yield rate in the pyrolysis process, the maximum liquid yield rate was reached at about 200℃. Pyrolysis residue and gas yield increased slightly and liquid yield reduced significantly with microwave heating compared with electric heating. Electric heating can achieve higher gas density and heat-value compared with microwave heating with proper heating rate when the temperature was above 400℃.The utilization of pyrolysis residue was discussed in this paper. The "carbon water slurry" with the mass fraction of pyrolysis residues being 60% had prepared with mixer that did not sediment within three days.