烘焙提升纤维素类生物质热解气化性能的研究进展

Research advances in improvement of cellulosic biomass pyrolysis/gasification process by torrefaction

生物质作为唯一含碳的可再生能源受到广泛关注。由于生物质具有含水率高、氧含量高、热值低等特性,在生物质热解气化中存在热转化效率低、焦油含量高、产品气热值低等问题。烘焙预处理对于改善生物质原料特性和提升热解气化性能具有积极的影响。本文阐述了烘焙预处理技术对于纤维素类生物质原料的疏水性、可磨性、元素组成、能量密度以及热解气化中产生的产品气组分、焦油组分、产品气热值等方面的影响。原料经烘焙预处理后疏水性、可磨性增强,热值增加,提升了原料品质。同时,经烘焙预处理的纤维素类生物质原料可明显提高热解气化性能,产品气中可燃气体组分含量、产量以及热值得到提升,焦油含量明显下降,提高了热解气化的产品气燃烧性能和利用品质。下一步应开展烘焙与热解气化耦合工艺及应用模式研究,提高生物质热解气化的整体经济性和产品附加值。

Biomass has received widespread attention as the only carbon-based renewable energy.Unfortunately,due to its high moisture,high oxygen content and low calorific value,direct conversion of biomass via pyrolysis or gasification is still encountering a number of issues,such as low conversion efficiency,high tar content and low calorific value of gas product.Pretreatment of biomass material by torrefaction exhibits a positive effect on improving the characteristics of feedstock and promoting the pyrolysis/gasification process.In this paper,the effect of torrefaction on the hydrophobicity,grindability,element composition,and energy density of cellulosic biomass feedstock,as well as the gas compositions,tar components,and calorific value of gas produced from pyrolysis/gasification are comprehensively reviewed.After torrefaction,the quality of the biomass materials is improved with enhanced hydrophobicity and grindability,and higher calorific value.At the same time,the pyrolysis/gasification performance of cellulosic biomass also can be promoted by torrefaction pretreatment,with higher combustible gas content,yield,and calorific value in gas product,as well as lower tar content.All these endow gas product with promising combustion performance and quality.Further researches on the coupling technology and application pattern of torrefaction and pyrolysis/gasification process should be carried out to improve the total economy and product added value for biomass conversion.