高固厌氧消化后的秸秆沼渣与褐煤共制备生物质型煤研究

Preparation of Bio-briquette from Lignite and Solid Digestate after High Solid Anaerobic Digestion of Corn Stover

生物质是可再生能源,合理利用生物质资源,不仅可以实现二氧化碳减排,还可以产生能源。文章以高固厌氧消化(HS-AD)后的秸秆沼渣和褐煤为研究对象,采用中心复合实验设计对影响沼渣型煤的工艺条件进行分析,最后对成型后的生物质型煤进行热重分析,以考察其作为燃料的燃烧特性。结果发现,如果对沼渣型煤的抗压强度要求为700N,最优工艺条件为成型温度为145℃,沼渣含量为23%,保压时间为120s。热重研究发现,生物质型煤热解过程表现为4个阶段,在第3个阶段,生物质型煤发生大规模热解,其中沼渣型煤的质量减少量在20%~30%,玉米秸秆型煤的质量减少量在30%~40%。升温结束后,沼渣型煤和玉米秸秆型煤的质量减少量分别为35%~45%和45%~55%。生物质型煤热解过程为褐煤与生物质的分阶段热解过程,与生物质和褐煤单独热解相比,其特征温度有偏差,在热压处理后褐煤与生物质热解过程可能存在协同作用,有助于褐煤转化。

biomass is a renewable energy. Rational utilization of biomass resources can not only reduce carbon dioxide emissions,but also generate energy. In this paper,solid digestate from high solid anaerobic digestion (HS-AD) of corn stover and lignite were taken as the experiment materials to produce bio-briquette,the central composite experiment was designed to analyze its process influence factors. The thermo-gravimetric analysis was also made for the produced bio-briquette to investigate its combustion characteristics. The results showed that,if the compressive strength of the bio-briquette was required to be 700 N,the process optimum condition were: molding temperature of 145 oC,solid digestate content 23%,and the holding time 120 s. Thermo-gravimetric analysis showed that the pyrolysis of biomass briquette had four stages. In the third stages,bio-briquette had a large amount of pyrolysis,the mass reduction of digestate-briquettes was 20%~30%,and that of corn straw briquettes was 30%~40%. When the heating was over,the mass reduction of digestate-briquette and straw-briquette were 35%~45% and 45%~55% respectively. The pyrolysis process of bio-briquette was lignite and biomass staged pyrolysis. Compared with the pyrolysis of sole biomass and sole lignite,the characteristic temperature was different. There may be synergistic effect between the lignite and the biomass pyrolysis after thermal treatment,which was helpful to the conversion of lignite.