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为了解低温烘焙对生物质在空气中长期储放特性的影响机制,以典型农业废弃物秸秆为研究对象,采用恒温恒湿箱分析烘焙秸秆的吸水特性,并分析了烘焙温度对秸秆平衡吸水率的影响规律。研究发现生物质颗粒的吸水过程主要表现为最初水分的快速增加和后期的缓慢增加到逐渐平衡2个阶段,其分别为表面孔隙结构的快速物理吸水和表面有机含氧官能团的化学吸附和缓慢水合引起的;烘焙温度不同,其吸水特性明显不同,烘焙温度越高,吸水速率越慢,平衡吸水率越低,经过260℃烘焙预处理,相比原样其平衡吸水率降低了40%;环境湿度对吸水性也有明显影响,随空气湿度的增大,吸水量呈指数型增长。这对生物质的长期储存和运输及后续热化学利用有重要意义。
In order to understand the mechanism of low temperature baking on the long-term storage characteristics of biomass in the air, take the typical agricultural waste straw as the research object, using the constant temperature and humidity box to analyze the water absorption characteristics of the baking straw and analyze the effect of baking temperature on the straw moisture balance The law of influence. It was found that the water absorption process of biomass particles mainly manifested as the rapid increase of initial moisture and the gradual increase from late stage to gradual equilibrium stage, which were rapid physical water absorption of surface pore structure and chemical adsorption of surface organic oxygen-containing functional groups and slow hydration ; The bake temperature is different, the water absorption characteristics are obviously different. The higher the bake temperature is, the slower the water absorption rate is, and the lower the equilibrium water absorption is, the pretreatment at 260 ℃ reduces the equilibrium water absorption by 40% On the water absorption has a significant impact, with the increase of air humidity, water absorption increased exponentially. This is of great importance to the long-term storage and transport of biomass and subsequent thermochemical utilization.