Abstract: As a more productive process, themophilic digestion has not been popularized in China for the possibility of negative net biogas yield. A heat demand model based on the biogas plant at Alviksgården, Sweden was established to calculate the heating load so as to investigate energy consumption and net biogas yield. By comparing to the mesophilic biogas plant with the same scale in Jintan, Jiangsu, the results showed that despite the energy consumption of the thermophilic biogas plant at Alviksgården 2.1 times of the mesophilic one in Jintan, with a much higher biogas volumetric productivity as 2.3 m³·m^-3·d^-1, the biogas yield increment from increasing the digestion temperature from mesophilic to thermophilic was considerably larger than the energy consumption increment used for heating. Based on the current biogas productivity of the biogas plant at Alviksgården, if waste heat recovery was introduced to further decrease energy demand in substrate heating, net biogas yield could be increased from 82% to 90%. While without waste heat recovery, biogas productivity should be increased to 4.2 m³·m^-3·d^-1 to reach the same net biogas yield, suggesting that waste heat recovery was more efficient and economical than increasing biogas productivity via improvement of digestion technology to further increase net biogas yield.

Key words: anaerobic, bioenergy, methane, biogas, thermophilic digestion, net yield , waste heat recovery

摘要： 以瑞典Alviksgården养猪场高温发酵沼气工程为分析对象，通过传热模型计算发酵罐加热负荷，通过与江苏金坛永康农牧养猪场同等规模的中温发酵沼气工程对比，讨论高温发酵的容积产气率和余热回收对沼气工程净产气率的影响。结果表明虽然瑞典Alviksgården养猪场高温发酵沼气工程的加热能耗是江苏金坛永康农牧养猪场中温发酵沼气工程的2.1倍，但由于产气速率达到2.3 m³·m^-3·d^-1，增产的沼气量远远大于增温的能耗；若进一步在瑞典Alviksgården养猪场沼气工程中增加余热回收，可将沼气净产气率从82%提高至90%。相对于提高容积产气率，采用余热回收技术对降低高温发酵沼气工程的增温能耗、提高净产气率效果更加显著。

关键词: 厌氧, 生物能源, 甲烷, 沼气, 高温发酵, 净产气率, 余热回收