甜高粱乙醇全生命周期温室气体排放

甜高粱是中国发展非粮乙醇的重要原料之一。为研究中国不同地区发展甜高粱乙醇的温室气体(greenhouse gas,GHG)排放表现并识别出影响温室气体排放量的主要环节,选取黑龙江东部、新疆中部、山东北部和海南4个典型地区的甜高粱液态发酵制乙醇生产系统为研究对象,设计3种不同的副产物利用情景,以生命周期分析方法计算并比较了乙醇在全生命周期内的温室气体排放量。研究结果表明:1)在不考虑副产物利用的基准情景下,甜高粱乙醇全生命周期GHG排放量为同等热值汽油的66%～77%;2)原料种植阶段是影响甜高粱乙醇全生命周期GHG排放量的主要阶段,柴油、灌溉用电和农用氮肥是种植阶段GHG的主要排放环节;3)对茎秆废渣实施再利用可降低甜高粱乙醇全生命周期GHG排放量,废渣燃烧为乙醇生产供能或以废渣为原料生产饲料可使甜高粱乙醇全生命周期GHG排放量降低50%～64%。该文为甜高粱乙醇规模化生产相关政策的制定提供参考。

Greenhouse gas emission of sweet sorghum ethanol in life-cycle

Sweet sorghum acts as one of the most promising crops for non-food bioethanol industry in China. In this study, four regions around China, namely East Heilongjiang, Central Xinjiang, North Shandong and Hainan are chosen to calculate the greenhouse gas(GHG) emission of sweet sorghum ethanol production and identify the main factors of the emission. Three scenarios for the sorghum bagasse byproduct re-use are designed for the calculation. The results show that 1) life cycle GHG emission of the four regions in the baseline scenario was 66%-77% that of 90# gasoline with the same heat value; 2) crop planting was a most important secsion affecting the life cycle GHG emission and the utilizations of diesel, electricity and N fertilizer in agricultral production were the main emission factors; 3) the utilization of bagasse byproduct can reduce life cycle GHG emission of sweet sorghum ethanol by 50%-64%. It can provide a reference for establishment of relative policy of sweet sorghum ethanol mass procluctim.