Phosphorus Metabolism Of Bio-ethanol In China Based On Material Flow Analysis

As one of China’s important strategic resources, phosphorus faces thecontradiction between demand and supply owing to the increasing requirement andunsustainable economic social metabolism. Bio-ethanol is the major developingliquid energy, whether the phosphorus metabolism in the life cycle of bio-ethanolincluding raw material plantation, transportation, ethanol conversion andconsumption would impact on the environment, whether the phosphorus flowswould close, whether it will affect the development strategies of phosphorus andbio-ethanol in China. How to reduce the burden of resource and environment withthe development of bio-ethanol, which need to be researched.The paper described the phosphorus metabolic pathways of corn-ethanol andcassava-ethanol in the whole life cycle using MFA. The research time was2008and the e!Sankey software was used to export the result. Among them,Heilongjiang Huarun alcohol Co. LTD, Jilin fuel alcohol Co. LTD and AnhuiFengyuan fuel alcohol Co. LTD were representative plants of corn-ethanol.Guangxi COFCO Co. LTD was the representative plant of cassava-ethanol. First,the model of phosphorus in the bio-ethanol life cycle was established whichinclude raw materials extraction, biomass production, ethanol production andwaste disposal in all stages. Then, the detailed accounting of each process wascarried on based on MFA. The static phosphorus MFA model of corn-ethanol andcassava-ethanol were obtained on the introduction of economic allocation ofproducts and co-products.The results of phosphorus flow and storage evaluation showed that thephosphorus metabolic structure of bio-ethanol industry had the characteristic ofhigh resource input intensity, low utilization and recycle efficiency, high wateracceptance and soil accumulation. The phosphate mining and factory processingstage accounted for larger proportion of total load of water pollution. Developmentof bio-ethanol had a larger effect on depletion time of phosphate rock, ifexpanding E85bio-ethanol in the nationwide, the depletion time of phosphate rockwould reduce roughly8-9years annually according to the existing resourceconsumption rate.Development of corn-ethanol is superior to cassava-ethanol from the angle ofphosphorus resource consumption.Development of cassava-ethanol had highereffect on the depletion time of phosphorus than corn-ethanol if the nationalaverage is concerned. Compared to corn planting, cassava needed to devote more phosphorus and had lower resource utilization and higher soil accumulation rate.The three provinces had a big utilization rate of phosphorus difference as for cornplanting. The phosphorus input amount of Anhui province was far higher than theother two provinces, the phosphorus utilization efficiency was26.08%while thesoil accumulation rate was as high as72.37%. Jilin province has a betterphosphorus circulation in corn planting stage compared to the other two provinces.It is more suitable for cassava-ethanol development than corn-ethanol in view ofwater pollution. Producing1t bio-ethanol,5.363kgP·t^-1and4.306kgP·t^-1respectively entered into water body in the life cycle of corn-ethanol andcassava-ethanol. Finally, the paper puts forward some suggestions such asoptimization of industrial structure, improving the reuse of co-products in allstages to improve the resource utilization efficiency and reduce environmentalpollution.