Experimental Study On Hydrothermal Carbonization Of Corn Straw

Hydrothermal carbonization of biomass is a new technology that uses high temperature and high pressure reaction conditions to convert biomass into environmentally friendly,high carbon content,and high calorific value solids.The development of hydrothermal carbonization technology is of great significance in reducing dependence on fossil energy and improving environmental pollution.This paper relies on the National Natural Science Foundation of China's "Study on the transport mechanism of carbon in the residue of biomass wet solution in a wet environment".Corn stover is used as a test material,and different reaction temperatures,different reaction times,and different liquid and solid states are performed respectively.Ratio of hydrothermal carbonization test.The determination of elemental composition,microstructure,chemical functional groups,and thermal stability of hydrothermal carbonized solid products was performed using a variety of characterization methods.A detailed and systematic study of the hydrothermal carbonization of corn stalks was carried out.The specific work was as follows:A hydrothermal carbonization experiment was carried out using corn stover at a reaction temperature of 180-290°C,a residence time of 8 h,and a liquid to solid ratio of10,and the yield of hydrothermal carbonized solid products,high calorific value,and characteristic functional groups were also investigated.Thermal stability for characterization analysis.The results showed that when the reaction temperature increased from 180°C to 290°C,the solid product yield decreased from 71% to 36%,and the high heat value increased from 20.8 MJ/kg to 29.79 MJ/kg.The analysis shows that the solid product is mainly composed of amorphous structure,and has a good degree of carbonation and aromatization.With the increase of reaction temperature,the solid product yield,high calorific value,and thermal stability are constantly rising.The functional groups gradually decrease.Using corn stalk as raw material,the reaction temperature(210°C,250°C,290°C,respectively)in the autoclave reactor,reaction time(30min,240 min and 480min),hydrothermal carbonation with liquid to solid ratio of 10.The characteristics of the solid product were measured and analyzed using a variety of characterization methods.The results showed that with the increase of reaction time,the solid product yield and characteristic functional groups gradually decreased.The high calorific value increased continuously,and reached the highest 29.29 MJ/kg at the reaction temperature of 290°C and 480 min.It is concluded that the effect of reaction time on the hydrothermal carbonization is significantly lower than the reaction temperature.A hydrothermal carbonization test was carried out using corn stover at a reaction temperature of 250°C,a reaction time of 240 minutes,and a liquid to solid ratio of 5,10,and 20.With the increase of the liquid-solid ratio,the solid product yield continuously decreased,and dropped to 35.2% at a liquid-solid ratio of 20.Through a variety of product characterization,it was found that excessively high liquid-solid ratios will promote the hydrothermal carbonization to tend to liquefaction,leading to a decrease in the yield of solid products.However,the increase of the liquid-solid ratio does not change the structural characteristics and high heat value of the hydrothermal coke.The analysis shows that the increase in liquid-solid ratio does not change the process of hydrothermal carbonization and the product properties.