(410c) One-Dimensional Modeling and Process Alternative for Biomass Torrefaction

Concerns about the continuous increase of pollution caused by use of fossil fuel make biomass as one of the promising renewable energy source. However, the inconvenient properties of the biomass including low calorific value, high oxygen contents, tenacious structure, hydrophilic nature and high moisture contents limit its use as a fuel. The biomass torrefaction is pre-treatment technique called mild pyrolysis or high temperature drying to improve fuel quality of the biomass. Some recent studies developed biomass decomposition kinetic models based on experimental data. However, a kinetic model involving the volatiles gas release during torrefaction and a heat balance model are lacking in previous studies which are required to develop the reactor design and the process design. This study used biomass decomposition model and volatile releasing model from Prins et al. (2005), to develop a new one-dimensional model for torrefaction reactor. This reactor model is applied to develop the conventional torrefaction process model in order to improve energy efficiency. The new proposed process design offers two opportunities: recover condenser heat loss and improved quality of combustion gas. Proposed design reduces the fuel consumption and generates more useful flue gas comparing with conventional design.

Reference: Prins, M. J. 2005. Thermodynamic analysis of biomass gasification and torrefaction. Thesis submitted to Eindhoven: Technische Universiteit Eindhoven, 2005.

Acknowledgement: This research was supported by the second phase of the Brain Korea 21 Program in 2012, Institute of Chemical Processes in Seoul National University, Energy Efficiency & Resources Development of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Knowledge Economy (MKE) and grant from the LNG Plant R&D Center funded by the Ministry of Land, Transportation and Maritime Affairs (MLTM) of the Korean government.