基于沼肥不同利用情景的禽畜养殖厂沼气工程能值分析

Emergy analysis of biogas project in livestock breeding plant based on different biogas manure use scenarios

对沼肥不同处理方式的禽畜养殖厂沼气工程进行能值分析,评价其生态经济性和可持续发展能力。以甘肃省兰州市花庄镇中荷沼气工程为例,对发酵出料直接排放及固液分离后排放两种情景进行对比,设定情景一为发酵出料排放灌溉;情景二为固液分离后沼渣作为有机肥基质出售,进而对两种不同情况的沼气工程能值投入、产出及其能值评价指标进行比较分析。结果表明,情景一和情景二的能值产出率分别为1.27和1.45,能值投资率分别为0.636和0.696,可持续发展指数分别为2.05和2.14;禽畜养殖厂沼气工程在能源生产、禽畜粪污处理方面均具有一定生态经济效益;与满负荷情况相比,在加入固液分离运行情况下系统的能值产出率提高14.2%,能值投资率增加4.7%,可持续发展指数上升,其余各指标均有3%至9%之间的减少,为提高能值产出率所付出的代价。综合考虑生态经济性和可持续发展能力,情景二是一种良好的增加沼气工程收益的运行模式。

This study aimed to conduct an emergy analysis of different biogas manure use patterns of biogas project in livestock breeding plant,and evaluate eco-economic benefit and sustainability.Taking the biogas project in Huazhuangzhen,Lanzhou City,Gansu Province as an example,emergy analysis method was applied to assess two kinds of fermented disposal processing method in a dairy cattle breeding center project,and this study was on the basis of these three aspects：emergy input,output and emergy evaluation indices.Set the conditions for the direct discharge of fermented feedstock to ground as case 1,and in case 2,fermented disposal is sold as the base of organic fertilizer after solid-liquid separation.The results showed that the emergy yield ratios of Scenario 1 and Scenario 2 were 1.27 and 1.45,the emergy investment ratios were 0.636 and 0.696,and the emergy sustainability indices were 2.05 and 2.14,respectively.The biogas project in livestock breeding plant has both ecological and economic benefits of energy production and livestock waste dealing.Compared with full-load operation,the energy value output rate EYR and the sustainable development index ESI increase in the Scenario 2（adding solid-liquid separation equipment）.The rate of EIR has also increased slightly;the rest of the indicators have been reduced by between 3% and 9%,which is the price paid for improving the energy yield rate.Considering the two factors of eco-economic benefit and sustainability,Scenario 2 is a well operation mode to increase the benefits of biogas project.