高密度方捆稻秸干发酵温度分布特性和产气效果研究

Distribution Characteristics of Temperature Field in Dry Fermentation of Rice Straw Rectangular Bales

发酵过程中温度的分布及其变化是沼气工程高效稳定运行的关键,文章以高密度方捆秸秆和猪粪为原料进行常温发酵,采用渗滤液回流和太阳能温室的手段增强传热传质效率,研究分析了中试规模下常温发酵温度场的分布特性和产气效率。结果表明:发酵周期内,库内物料均温呈现迅速上升后缓慢降低的趋势,日均温变化≤0.2℃,沼液温度在发酵周期内呈上升趋势;而各层的平均温度高低呈现第3层>第1层>第2层,其稳定性呈现第3层>第2层>第1层;日产气量随着温度的增加而增加,至峰值后下降并保持稳定,日产气量到达峰值的时间比物料均温到达最高值的时间略有延迟,此次试验的有效容积产气率为0.33 m3·m-3d-1,发酵稳定后甲烷浓度保持在50.42%以上。

The distribution of temperature is the key to the efficient and stable operation of the biogas project during the fermentation process. In this paper,the high density straw rectangular bales and the pig manure were used as raw materials,the distribution characteristics of the temperature field and gas production efficiency were investigated at ambient temperature on pilot scale. The heat transfer and mass transfer efficiency were enhanced by means of leachate reflux and solar greenhouse. The results showed that,during the fermentation period,the average temperature of materials in the reactor showed a trend of the first rising rapidly and then decreasing slowly,and the daily average temperature changing ≤0. 2℃.Meanwhile,the biogas slurry temperature showed an increasing trend in the fermentation cycle. The average temperature of each layer was the third Layer the first layer the second layer,and the stability was the third layer second layer the first layer. The daily gas production increased with the increase of temperature,drop and remain stable after peak. The daily gas output peak time was slightly delayed compared to the highest material temperature peak time. The biogas production rate of effective volume was 0. 33 m3·m-3 d-1,and the methane concentration was above 50.42%.