Paper Title
Upgradation of Biomass via Pretreatment for Production of Biofuels : A review

Abstract
Utilization of biomass has been intimately associated with renewable energy in the recent years. However, the undesirable properties of biomass such as bulk volume, low density, high moisture content and its heterogeneity pose a barrier to its competitiveness in the market of energy generation. Pretreatment of biomass can help to solve above problems as well as increase the conversion efficiency of lignocellulosic biomass into biofuel (ethanol, biogas, solid fuel), which has the potential to replace the fossil fuel. A large number of pretreatment methods have been explored during the last few years such as steam treatment, hot water treatment, alkali treatment, microbial treatment, torrefaction etc. Among all this physiochemical and thermochemical pretreatment methods, steam explosion and torrefaction are widely used for production of solid biofuels. The purpose of pretreatment is to produce a high-quality solid biofuel that can be used for densification, combustion and gasification. In this review, the characteristics of steam explosion and torrefaction will be described. Different conditions of steam explosion and torrefaction for various biomass will be presented and discussed. The mass yield and energy yield as a result of torrefaction will also be discussed. Keywords - Agricultural Residues, Biomass Pretreatment, Steam Explosion, Torrefaction, Bioenergy.