Dual pressures currently arising from energy shortage and environmental degradation worldwide make it critically important to utilize renewable biomass resources for energy. But due to the requirement for the safety of food and feed, triglyceride feedstocks (currently derived mainly from vegetable oils and animal fats) and lignocellulose among the various kinds of naturally-occurring biomass are practical sources for production of liquid biofuels instead of fossil fuels. In this respect, we review the recent progress in the transformation of triglyceride feedstocks and lignocellulose into liquid biofuels by different catalytic routes. These routes include thermal cracking, hydrogenation and transesterification for oils and fats, and gasification-Fischer-Tropsch synthesis, liquefaction-upgrading and selective synthesis via platform chemicals for lignocellulose. The catalysts and processes involved in these catalytic routes are intensively discussed, and their existing problems and possible solutions are addressed, which may provide insights helpful for further studies on the more efficient utilization of biomass for energy. Contents
1 Introduction
2 Conversion of oils and fats
2.1 Thermal cracking
2.2 Catalytic hydrogenation
2.3 Transesterification
3 Conversion of lignocellulose
3.1 Gasification-Fischer-Tropsch synthesis
3.2 Liquefaction-upgrading
3.3 Selective synthesis via platform chemicals
4 Outlook