Yassir Makkawi
Aston University United Kingdom
Title: Bioâ€fuel production in a downer reactor: a computational modelling study
Biography
Biography: Yassir Makkawi
Abstract
In seeking methods to reduce the dependence on fossil fuels and reduce the CO2 emission, considerable research and development efforts is currently focused on renewable energies to serve both sectors of transportation fuel and electricity generation. Currently, biomass contributes 10% to the global annual energy production and this is expected to considerably increase in the next decades. The biomass can be thermally treated in a controlled environment (reactors) to produce three main bioâ€fuel products in the form of gas, liquid and char. The nature of the dominant product depends strongly on the reactor temperature and the gas residence time. A high temperature (>650 °C) and medium residence time ~2 s favours the formation of gas (gasification), while a low temperature (<600 °C) and short residence time <2 s in the absence of oxygen favours the formation of liquid oil (pyrolysis). In this study, a comprehensive chemical reactions model for the biomass gasification and pyrolysis is implemented in a CFD software (ANSYSâ€FLUENT) for the simulation of the biomass conversion to fuel in a downer reactor. The proposed chemistry scheme includes reactions for devolatilization, tar cracking and a range of homogeneous and heterogeneous reaction, thus bridging the gap between biomass pyrolysis and gasification reactions in one unified model. The model has the advantage of being computationally fast and easy to implement as a user defined function (UDF) in wide ranges of CFD commercial software, hence, benefiting both academic and industry sectors. Finally, based on the model predictions, the study present concluding remarks on the potential of the proposed process for industrial scale processing and recommend optimum conditions for a targeted product (i.e. liquid oil, gas or char).