Simultaneous CO₂ and SO₂ Capture at Fluidized Bed Combustion Temperatures

Simultaneous carbonation and sulphation have been investigated to simulate non-calcining conditions at FBC temperatures (750–850°C) using an atmospheric-pressure thermogravimetric reactor (TGR) with up to 80% CO₂ in the gas stream to extend the pressure range of applicability of the results. This investigation was undertaken to provide insight on simultaneous carbonation and sulphation and to provide knowledge relevant to FBC, including PFBC, operations. Two calcium-based sorbents (one limestone and one dolomite) were tested with particles of diameter 212–250 μm and 500–600 to determine the effects of operating conditions such as temperature, CO₂ and SO₂ concentrations, particle size and reaction time on the sorbent performance. SO₂ was found to impede CO₂ capture; on the other hand, CO₂ enhanced the capture of SO₂. The calcination rate was also observed to decrease as a result of the presence of the sulphate layer.