Hybrid Life Cycle Analysis For Coal And Straw Briquette

Increasing demands,limited reserves,and concerns about the environmental consequences of fossil fuels have driven interest in bio-energy for government,scientific research organizations,and correlative enterprises.As a big agricultural country,China is abundant in straw resources,producing more than 700 million tons of straw per year.Unfortunately,most of the straws are burned in the field unreasonably,which makes waste of resources and pollution of environment.Straw briquette technology is a technology which refers to refers to press the straw in which moisture content is about 10%into all kinds of shaped fuel such as bar-formed,pellet-formed and block-formed under certain pressure(heat or unheated).The life cycle energy consumption,environment impacts,and economics of coal and straw briquette were investigated by using hybrid life cycle analysis(LCA).Energy return ratio(r_E),resource depletion index(RDI),environment impact load(ELL) and life cycle cost (LCC) were adopted in this study.Moreover,in order to balance energy,environment and economics indicators,EEE indicator was adopted as the combined indicator to evaluate the objects comprehensively.The goal of this project is to provide theoretic base and data support for using straw briquette replacing coal,the conventional fuel of China.And then, government can making decisions according to the results.For the whole life cycle,straw briquette provides a net energy gain,so it can be a viable substitute for fossil fuel.However,its value of energy return ratio is only about 50%of that of coal.The resource depletion index of straw briquette is 82.1%lower than that of coal,so the generalization of straw briquette can reply the actuality of freshwater scarcity.Straw briquette has lower global warming potentials,acidification potentials,eutrophication potentials,smoke and dust potentials,and solid waste potentials,meanwhile,the environment impact load of straw briquette is 81.4%lower than that of coal,so the generalization of straw briquette can alleviate local environment load.The life cycle cost of straw briquette is 19.5%higher than that of coal,so the generalization of straw briquette needs the financial support of government. Lastly,the EEE indicator of straw briquette is 79.8%smaller than that of coal,therefore, straw briquette is a better type of energy comparing with coal,taking the energy, environmental and economical aspects into consideration.Although straw briquette has the potential of displacing coal,its industrialization development is restricted by three bottle-neck factor:raw material,producing technology,and exterior environment.Therefore,measures should be taken in order to expedite the practicality,high-efficiency,and low-cost development of straw briquette,with the government policy supporting and the advancement of briquetting technology.