Experimental Research On The Hydrothermal Carbonization Of Rice Straw

Hydrothermal carbonization (HTC) was carried out to investigate the influences of temperature from200℃to280℃and residence time from Oh to2h on the characteristics of straw in a1000mL autoclave in this study. The paper analyzed the relationship between HTC conditions and each phase of the product yield as well as property of products. The optimaized reaction condition of straw HTC was established. Analyzing yields of the gas, liquid and solid product as well as investigating the biochar of property under HTC, according to the calorific value the energy density, the energy yield, elemental analysis and other indicators. In addition, by investigating the water absorption experiments and analysis of scanning electron microscopy for biochar practicality, the paper ascertained the HTC mechanism of straw to provide a basis for designing controllable HTC route the development of the possibility of using straw fuel instead of fossil fuels.The temperature and residence time were important affect of the HTC of bio mass. The gas product of the HTC was CO2, and those liquid products were reducing sugar and acetic acid. With the severity of the reaction conditions (raising the temperature or extending time), the content of carbon dioxide and acetic acid increased, and the bio-char yield decreased. On the contrary, reducing sugar in the low-temperature and short residence time obtained the maximum yield, the yield decreased gradually with increasing temperature. Under suitable reaction condition, we can obtain a higher recovery of the target liquid products (reducing sugar or acetic acid), thereby improving the economic efficiency of the hydrothermal carbonization process.The energy density of biochar increased with increasing the reaction temperature and prolonging the residence time,When they were260℃and1h respectively, the The energy density of biochar had been improved by69.45%which was the highest value.And further reinforcing the violence of the reaction could limited improve the energy density.The suitable temperature and residence time could maximize the economic benefits with controling the operation cost.The Water absorption experiment results showed that when the reaction temperature was260℃and the residence time was1h,the products absorption of solid phase was lower.Under this conditions, the properties of biochar was good,so it was suitable to prepare biochar. The SEM showed that biochar presented the fragmented state, besides accompanied a large amount of honeycomb structure after the HTC, it may be caused by the decarbonylation which lead the decomposition of cellulose, hemicellulose and lignin.