Comparative Study of Steam- and Nitrogen Explosion Pretreatment Methods

The aim of this paper was to investigate chemical and physical changes in biomass during N2 explosive decompression pretreatment and compare it with steam explosion pretreatment. The methods are economically and environmentally attractive since only pressure and water/steam are used to break down the biomass structure. Two pretreatment methods were used at different temperatures and samples from all process steps were analysed. The results were used to assess the pretreatment effect and the chemical changes in biomass and, finally, the mass balances of the bioethanol process at different process steps. Results show that the highest glucose and ethanol yields were obtained with the steam explosion pretreatment method at 200 °C (24.29 g and 12.72 g per 100 g biomass, respectively). At lower temperatures, the nitrogen explosion treatment produced better yields.