Environmental Assessment of Biomass Conversion Technologies: Are Slow Pyrolysis Processes Suitable for Mitigating Global Warming?

摘要

The greenhouse effect and sufficient global food supply are two of the most urgent problems of mankind.Biochar produced by pyrolysis processes can fix carbon long-term and might increase yields when applied to agricultural soils.To assess environmental impacts associated with processes and products along their life cycle,the ISO 14040 has been established.Based on this approach,the mitigation of global warming by applying slow pyrolysis processes has been assessed.Pyrolysis converts biomass under absence of oxygen into three different fractions-solids,liquids and a gaseous phase.Various utilization paths are possible for the products; they can for instance substitute other (fossil) fuels in energy generation units,or the solid product can serve as soil enhancer.Within a project funded by the European Union's INTERREG-programme,four different cases of using products from slow pyrolysis have been compared regarding their global warming mitigation potential.The life cycle assessment carried out has shown that co-firing of the produced char in power plants can be a suitable way to make the energy sector less carbon intensive.But in the long term and in order to even reduce the concentration of carbon dioxide in the atmosphere,the application of Biochar in the agricultural sector is a most promising alternative.However,there is still a lot of research needed to better understand the effects of Biochar in different types of soil with respect to e.g.nutrient and water management and,thus,its impacts on plant growth,fertilizer and irrigation demand.