State of Scale-Up Development in Chemical Looping Technology for Biomass Conversions: A Review and Perspectives

The chemical looping technology is an emerging technology for the efficient conversion of biomass to heat, power, fuel, and value-added chemicals. Chemical looping uses a metal oxide oxygen carrier to fully or partially oxidize the biomass feedstock, which avoids N2 dilution to the CO2 or syngas product. Thus, chemical looping technology can convert biomass to sequestration-ready CO2 or high purity syngas, which leads to the potential for negative carbon emission and enhanced energy efficiency in biomass conversions. Various chemical looping processes for biomass conversions, using different oxygen carrier materials and reactor designs, have been studied ranging from lab scale to pilot scale. This article reviews the current state of development in the scale-up of chemical looping technology for biomass conversions. It also provides perspectives on the chemical looping technology of relevance to various biomass conversion issues including CO2 capture, utilization and sequestration, biomass feedstock collection, handling and conversion enhancement, choice of reaction schemes, fuel and air reactor designs and operation, operational load variation, fate of pollutants and effect of ashes. Representative process configurations, reactor designs, oxygen carrier material selections, and the testing results are described along with the technology challenges, their potential solutions, and future research needs.