厌氧发酵制备生物燃气过程的物质与能量转化效率

以稻壳为原料,采用批式中温(35℃±1℃)厌氧发酵工艺研究了稻壳厌氧发酵制备生物燃气的产气性能,在此基础上结合物质流分析方法分析了发酵过程中C、N元素的分布情况以及物质与能量的转化效率。研究结果表明稻壳厌氧发酵制备生物燃气过程的产气率和产CH₄率分别为297.41和164.40 ml·(gVS_RH)^-1,平均CH₄含量为55.28%;C元素流向分布:30.7%生物燃气,6.4%沼液,62.9%沼渣;N元素在剩余物中的流向分布:63.2%沼液,36.8%沼渣;稻壳厌氧发酵制备生物燃气的物质转化效率和能量转化效率分别为30.0%和33.7%。本研究为农业加工废弃物的资源管理和能源化利用提供了理论依据。

Material and energy conversion efficiency of biogas preparation process by anaerobic fermentation

The yield of biogas produced by mid-temperature (35℃±1℃) anaerobic fermentation of rice hulls was investigated, and material and energy flows as well as the distribution of element C and N during this fermentation process were also analyzed using the material flow analysis (MFA) method in this paper. The results showed that during the fermenting rice hulls to prepare biogas, the production rates for biogas and for CH₄ were 297.41 and 164.40 ml·(gVS_RH)^-1, respectively; implying that average CH₄ content in biogas was 55.28%, corresponding to 31.16% of the theoretical yield. Based on MFA for the fermentation process system, 30.8% and 6.4% of C element were converted into biogas and slurry, and 62.9% left in residue, separately; 63.2% of N element were converted into slurry and 36.8% left in residue, while negligible N element was in biogas. The efficiencies of material and energy for conversion of rice hulls to biogas were 30.0% and 33.7%, respectively. This study could be as a theoretical basis for resource management and energy utilization of agricultural wastes.