Life cycle assessment on biofuel production from biomass gasification and syngas fermentation

Abstract

Biomass is gaining popularity in research for the development of new renewable and eco-friendly energy sources. Since lignocellulosic biomass, resources are ample and renewable. One of the methods to convert biomass into usable gaseous fuel is gasification process. Gasification is a very simple process to convert solid fuels into gaseous fuels. It can be used to gasify even low-grade agricultural solid residues to combustible gases to meet the energy requirements in a decentralized manner. Since gasification results in fewer pollutant emissions, it is also an environmentally clean way of utilizing fuels. In this proposed study, comparative life cycle Assessment will be performed for power generation from biomass downdraft gasification and syngas fermentation for biofuel synthesis in two stages. The present investigation is to analyse the Prosopis Juliflora biomass waste intended for ultimate, calorific value and proximate analysis and to evaluate their characterization as feedstock for utilization in gasification process. In the first stage, the feedstock is first fed into downdraft gasifier from top to bottom, followed by a sequence of operation namely drying, pyrolysis, oxidation, and reduction for syngas generation. The synthesis gas derived from biomass downdraft gasification often contains additional components such as tar, acetylene, ethane and ethylene. The impurities available in the synthesis gas causes a potential scaling in the ways and by inhibiting microbial catalyst, which involves a cellular low growth and poor yield in product. Some recent studies reported that syngas has been converted into liquid fuel by using Fisher trophic synthesis, but it requires a catalyst. So, in the second stage the syngas fermenter with the capacity of 7-L would be designed and fabricated for the continuous production of 1 g/L biobutanol from purified syngas using the mixed culture mainly consists of C1 fixing homoacetogenic and C4-producing butyrate microorganisms or butyrogens. The produced syngas can also be used directly as a fuel for Solid Oxide fuel cell applications.