Characteristics of pyrolysis products of biomass under cryogenic pretreatment using liquid nitrogen
Biomass,as a renewable energy source,features wide availability,multiple functions,and carbon neutralization.The high-value resource utilization of biomass is conducive to reducing reliance on high-carbon fossil energy,ensuring na-tional energy security,and curbing environmental pollution,aligning with the needs of China's"dual carbon"national strategy.Pyrolysis,as the foundation of biomass thermochemical conversion,is one of the best technologies to achieve a high-value utilization of biomass energy.However,it has some core issues such as low bio-oil yield and poor quality.To overcome these problems,a cryogenic technology was innovatively applied to the field of biomass pyrolysis,and a new biomass oil production method of"cryogenic+fast pyrolysis"was proposed to increase the yield and quality of pyrolytic bio-oil.Taking two types of crop straw as experimental research objects,the rapid freezing pretreatment method with li-quid nitrogen was adopted to study the evolution mechanism of the product distribution and composition of biomass pyro-lysis under cryogenic pretreatment.The experiments show that compared with conventional pyrolysis,the increase in the bio-oil yield after cryogenic pretreatment of biomass pyrolysis can reach 14.16%to 23.73%,and the cryogenic pretreat-ment temperature has a positive correlation with the bio-oil yield,and the maximum bio-oil yield(22.3%to 26.3%)is reached at-90℃,exceeding the bio-oil yield of the aluminum method by 8.50%to 22.71%.The cryogenic pretreatment has a significant transformation effect on the composition of the bio-oil,and the content of benzene series(BTEX)and phenolic substances in the bio-oil composition increases significantly,with the maximum increase of 43.61%and 12.45%,respectively.The cryogenic pretreatment of liquid nitrogen inhibited the release of CO2 and CO in biomass pyrolysis gas,and the proportion of components decreased by 7.2%-29.7%.In addition,the inhibition of the release of CO2 and CO in the biomass pyrolysis gas and the increase of CH4 and H2 by cryogenic pretreatment increase by 0.2%to 14.7%.Moreover,the increase in C content and the decrease in O content in the solid product under cryogenic pretreatment are conducive to improving the combustibility of biochar and reducing its risk of spontaneous combustion.
万方数据
维普
