气化温度对生物质气化的可燃气、炭和焦油特性的影响

Effect of gasification temperature on the properties of the bio-gas,bio-char,and tar derived in biomass gasification

【目的】生物质气化技术是一种清洁可再生的能源利用技术。研究气化温度对气化产物特性的影响机制,构建气化产物特性的演变规律,对中国实现碳达峰与碳中和目标具有重大意义。【方法】以玉米Zea mays秸秆、棕榈Trachycarpus fortunei壳和马尾松Pinus massoniana等3种农林生物质废弃物为原料,以空气为气化剂,采用自制的微型固定床气化装置,开展3种生物质的气化多联产研究,系统研究了不同气化温度(700、800、900℃)对气化性能的影响,以及对气化三相产物(可燃气、生物质炭与焦油)特性的影响机制。【结果】随着气化温度从700℃增加至900℃,可燃气的质量产率逐渐增加,而生物质炭和焦油的质量产率逐渐减小。较高的气化温度有利于提升可燃气的热值。在3种原料中,马尾松可燃气的热值最高,一氧化碳、氢气和甲烷体积分数分别为40.03%、18.27%和18.29%,低位热值达13.58 MJ·m^(-3)。随着气化温度的增加,生物质炭中的碳元素质量分数增加,氢元素质量分数下降,灰分质量分数大幅增加,其中马尾松炭的热值最高,达29.70 MJ·kg^(-1)。随着气化温度的增加,3种原料的气化液体产物中酸类、醇类、醛酮类、呋喃类化合物相对含量逐渐减小,而芳烃类化合物相对含量大幅增加,其中马尾松的芳烃类化合物相对含量最高,达到61.12%。【结论】气化温度对生物质气化三相产物的产量及特性有显著的影响,选择合适的气化温度对提高生物质可燃气热值及气化效率至关重要。

[Objective]Biomass gasification technology is a clean and renewable energy utilization approach.The purpose of this study is to investigate the influence mechanism of gasification temperature on the properties of gasification products,and to build the evolution law of the characteristics of gasification products,which is of great significance for China to achieve the goal of carbon peaking and carbon neutrality.[Method]Three types of lignocellulosic biomass,namely Zea mays,Trachycarpus fortunei,and Pinus massoniana,were gasified in a home-made fixed bed gasification reactor.The effect of different gasification temperatures(GT)(700,800,900℃)on gasification performance were systematically studied,as well as the mechanism of their effects on the characteristics of gasification products(bio-gas,bio-char,and tar).[Result]With the increase of GT from 700℃to 900℃,the yield of bio-gas gradually increased,while the yields of bio-char and tar gradually decreased.Higher GT resulted in better quality of bio-gas.Among the three types of biomass,bio-gas from P.massoniana had the highest calorific value.The contents of CO,H_(2),and CH_(4) were 40.03%,18.27%,and 18.29%,respectively,and the lower calorific value was 13.58 MJ·m^(−3).With the increase of GT,the contents of C and ash increased,while the contents of H decreased.The calorific value of bio-char from P.massoniana was the highest,reaching 29.70 MJ·kg^(−1).With the increase of GT,the content of acids,alcohols,aldehydes,ketones and furans in the liquid products of biomass gasification gradually decreased,while the content of aromatics increased significantly,with the highest aromatic content in P.massoniana,reaching 61.12%.[Conclusion]GT has a significant influence on the yield and properties of gasified products.Optimizing the gasification temperature is crucial for improving the calorific value and gasification efficiency.