Reduction of carbon dioxide emission through the sorption in situ using a fluidised bed reactor

The paper discusses the possibility of using the reversible reaction CaCO₃ ↔ CaO + CO₂ for the cyclic capture and release of CO₂ directly inside a fluidised bed combustor. This could lead to the lowering of CO₂ emissions into the atmosphere, as part of an effort to mitigate the greenhouse effect associated with the rising atmospheric CO₂ concentrations resulting from obtaining energy from burning fossil fuels.

An enrichment coefficient E has been introduced and defined as a measure of the production of CO₂ (on calcining CaCO₃) or its removal (on carbonation of CaO) with respect to the level associated with fuel combustion alone. The observations made on the effect of introducing an additional external stream of CO₂ on the efficiency of the chemical capture process have been described. Through an appropriate control of the temperature inside the reactor it is possible to change the value of E over the range [-0.8; 0.8]. This implies that up to about 80% of the CO₂ derived from the fuel can be temporarily retained within the bed and released later, at a higher concentration. The proposed method of burning fuel in a chemically active fluidised bed could be an available method leading to CO₂ isolation from the flue gases and leading to its eventual sequestration.