生物质微波热化学转化技术

Microwaveassisted Thermochemical Conversion Technologies for Biomass

在人口和经济持续增长的驱动下,全世界对能源的需求将持续稳定增长.生物质来源广泛,价格低廉,是化石燃料最理想的替代品之一,因此生物质能源的转化利用是当今的研究热点之一,而微波的引入为生物质的转化利用技术带来了新的契机.本文重点介绍了生物质微波热化学转化技术,主要包括干燥、液化、烘焙、炭化、热解及气化等.结果表明,微波的引入在不同方面改良了相应的生物质利用技术:微波干燥得到的产品水分更低,品质更高;微波液化转化效率更高,产物油中水分含量更低;微波烘焙成品均匀,低温转化效率更高;微波炭化产物热值更高,热惰性小;微波热解反应时间更短,产油率更高;微波气化产物CO_(2)含量降低,热值提高,飞灰减少.生物质微波热化学转化反应器的开发仍处于试验阶段,工业化设备在连续性和大容量方向有待进一步的研发设计.

Influenced by the continuous growth of population and economy,the demand for energy in the world will continue to grow steadily.Biomass is one of the most ideal alternatives to fossil fuels due to its wide range of sources and low price,and the conversion and utilization of biomass energy has become one of the hottest re-search topics.Traditional biomass conversion and utilization technologies include drying,liquefaction,torrefac-tion,charring,pyrolysis and gasification,and the use of microwave has brought new opportunities for biomass conversion and utilization technologies.In this review,the main characteristics of different microwave assisted biomass conversion and utilization technologies and their differences as compared with the traditional electric heating conversion technologies are detailed.The results show that microwave improves biomass utilization tech-nologies in different aspects:(a)the product obtained by microwave drying has lower moisture content and higher quality;(b)the conversion efficiency of microwave liquefaction is higher,and the water content in the product oil is lower;(c)the structure of product from microwave torrefaction is more uniform,and the conver-sion efficiency at low temperature is much higher;(d)microwave charring products have higher calorific value and less thermal inertia than traditional carbonization;(e)microwave pyrolysis reaction time is shorter and oil production rate is higher;(f)the CO2 content of microwave gasification products is reduced,the calorific value is increased,and the fly ash is reduced.The development of the reactor used for biomass thermochemical con-version is still in the experimental stage,and the relevant industrial equipment for continuity and large capacity needs further research and design.