General Plan On Development Of Crop Straw Reuse In Heilongjiang Province

China’s recent agricultural surveys indicated that the crop straw has bec ome agricultural waste by several situations, including the insufficient and unthoroughly institutional specifications of agricultural production, the decrease of rural labor force, and improvement of farmers’ life demand. For these reasons, more and more crop straw was opening burned. This kind of handling destroyed the agricultural production and environment, and became an important source of air pollution in many areas of China. The development rational resource and energy utilization of crop straw will be a critical access to improve the ecological environment in rural areas, increase farmers’ income and achieve sustainable development of agriculture. Heilongjiang province is an important national commodity grain base with substantial straw wasting, wider straw distribution and lower utilization rate. The successful experiences of straw’s comprehensive utilization will be a reference and promotion for other cold region even the whole country. In this study, we inves tigated comprehensive benefits of straw collection-storage-transportation systerms and reuse techonologies, economic and environmental collection radius of straw’s resources and energy engineering in thirteen administrative regions of Heilongjiang province.Agricultural straw utilization not only has economic benefits by save fossil fuels but also helps to solve environmental problems by reducing agricultural waste. The straw utilization methods should be evaluated by both sides of these effects. By using emergy analytical method, the economic/environmental benifits and sustainability of straw collection, storage, transportation in Heilongjiang province have been assessed. The results from straw collecting indicate that both manual and three types of mechanized collecting ways have promising environmental benifits and sustainability, and the economic benefits order, from high to low, is manual collecting, mechanized collecting type A, mechanized collecting type B, mechanized collecting type C. In straw storage section, warehouse(engineering plants) storage has the best economic benefits than outdoor(relay station) and warehouse(relay station). The analysis in straw transportation section reveal that baled straw transportation has more comprehensive benefits than unbaled straw within 60 km distance, and truck has more comprehensive benefits than tractor when transporting baled straw more than 40 km, or unbaled straw more than 12.5 km.Secondly, straw utilization can bring economic benefits, reduce agricultural waste and solving environmental problems simultaneously. Therefore, economic and ecological benefits concern are equally important for the development of straw resources and energy engineering. Emergy value method is used to analyze these situations. Net energy yield ratio(EYR), environmental loading ratio(ELR),emergy sustainability index(ESI) and renewable emergy ratio(R%) are selected as evaluation indexes to estimate overall efficiency of distinct projects, such as straw-biogas fermentation, straw-ethanol fermentation, straw moudling, straw-fired cogeneration and cogeneration engineering. The most efficiency systems of each methods are used to compare and analyze. The economic benefits rank of these five systems is straw moudling > straw-biogas fermentation > straw-ethanol fermentation > straw-fired cogeneration > gasification power generation system. The straw moudling system had the most economic benefit. The rank of enviromental benefits is straw moudling > straw-biogas fermentation > straw-fired cogeneration > gasification power generation system > straw-ethanol fermentation. The rank of potential of sustainable development is straw moudling > straw-biogas fermentation > straw-ethanol fermentation > straw-fired cogeneration > gasification power generation system. In summary, straw moudling has the best comprehensiv e benefits and fit for straw resource engineering in Heilongjiang. The actual decision will depend on regional development planning and local economic and environmental conditions.Furthermore, we propose straw resources and energy engineering economic evaluation model to solve high costs and instable supply problem when straw as a raw material. The model is based on the supply radius breakeven theory. We analyze the optimal economic radius of 13 each administrative region in Heilongjiang Province with this model. Straw-biogas fermentation, straw-ethanol fermentation, straw moudling, straw-fired cogeneration systems are studied. The results show the optimal economic radius for straw-biogas fermentation is 35.6~58.3km, for strawethanol fermentation is 31.1~58.3km, for straw moudling is 3.5~7.1km, for strawfired cogeneration is 20.1~31.2km. Another conclusion is that the density of straw resources in certain area impacts the economic radius mostly. For example, Suihua has the highest density straw resources in Heilongjiang province, which results in the shortest economic radius. The model also reveals straw-biogas fermentation and straw-ethanol fermentation engineering have longer economic radius than straw-fired cogeneration, and economic radius is commonly short for straw moudling. When the economic radius exceeds the maximum transport radius of an area, the results should be subject to the maximum transport radius.The increasingly serious air pollution caused more severe diseases and incidents. Straw resource and energy utilization will reduce the source of air pulltion substantially. Based on this purpose, this study building a new model to evaluate the enviromental benefits of straw resources and energy utilization. Harbin was investigated by this model. The results showed that distinct straw resources and energy utilization systems would decrease greenhouse gas emission with the rank as straw-biogas(106301t CO2 eq.) > straw-ethanol(9690t CO2 eq.)>straw-fire cogeneration(2673t CO2 eq.)>straw moulding(51t CO2 eq.). The rank of PM2.5 total reductions is straw-biogas(1539512g) > straw-ethanol(1379045g) > straw-fire cogeneration(545428g) >straw moulding(18045g). When transportation radius was fixed as 15 km, for example, greenhouse g). When transportation radius was fixed as 15 km, for example, greenhouse gas emission reduction rank is straw moulding(12523t CO2 eq.)>straw-biogas(1785t CO2 eq.)>straw-fire cogeneration(1359t CO2 eq.) > straw-ethanol(770t CO2 eq.); PM2.5 total reductions of each system are all around 0.25 t.In summary, the comprehensive benefits and sustainablity assessments of different types of straw collection-storage-transportation and individual engineering systems will be conducive to local straw utilizing method selection. These analysis will supply reference data for the developing of straw reusing, system construction and project planning in Heilongjiang province.