Capture of CO2 during low temperature biomass combustion in a fluidized bed using CaO. Process description, experimental results and economics

AbstractThe process discussed in this work is aimed at the capture of CO2 with CaO in a circulating fluidized bed (CFB) combustor-carbonator reactor, where the combustion of biomass with air and the carbonation of CaO are taking place simultaneously. This process exploits the high reactivity displayed by most natural biomass materials during their combustion at low temperatures (around 700 °C) and the capability of CaO to absorb CO2 at these temperatures. This is a niche application for the calcium looping cycles being developed for other post-combustion and precombustion processes. The CaO necessary for the CO2 capture reaction by carbonation is being circulated from an oxyfired circulating fluidized bed calciner, operating at temperatures over 900 °C to permit the decomposition of CaCO3. In this publication, we present new experimental results proving the concept in a 30 kW test facility consisting of two interconnected CFB reactors (combustor-carbonator and combustor-calciner). An application case study is discussed, together with an economic analysis using published data of similar systems