秸秆沼气发酵工程反应罐内传热分析

The Heat Transfer Analysis for Straw Biogas Fermentation System

文章针对国内外广泛关注的秸秆沼气工程,基于热力学原理,结合实验和理论,对秸秆发酵系统中罐内温度分布进行了分析。结果表明,由于秸秆的加入,会导致体系内部温度不均匀性加重,8 wt%秸秆体系的总传热系数相比于纯水体系降低了17%,其原因主要在与秸秆自身特性与换热温差;另外冷物料的直接进料会加剧罐内温度波动,进口物料的预热处理和搅拌是解决秸秆发酵过程传热速率与效率低的主要方法。

As a widely concerned straw biogas plant, this paper analyzed the temperature distribution and heat transfer rate/efficiency in the reactor based on thermodynamics and experiments. It was found that the temperature inhomogeneity was aggravated inside the reactor due to the adding of straw. Comparing with the water system, the 8 % （wt）straw system reduced the total heat transfer coefficient （K） by 17%. The key reasons were because of straws＇ itself characteristics and the heat transfer temperature difference （Atm）. In addition, cold feedings will increase temperature fluctuations within the tank. Preheating the feedings or stirring may solve the problem of low heat transfer rate and low efficiency for straw fermentation.