Cyclic CO2 capture of carbide slag modified by pyroligneous acid in calcium looping cycles

Abstract

ABSTRACTCarbide slag is a kind of industrial waste obtained in the production of acetylene that is the raw material of polyvinyl chloride in chlor‐alkali plants. The carbide slag modified by pyroligneous acid was proposed as a CO2 sorbent at high temperature. The CO2 capture capacity of the carbide slag modified by pyroligneous acid in the calcium looping cycles was investigated in a thermogravimetric analyzer and a dual fixed‐bed reactor. The modified carbide slag exhibits better CO2 capture capacity than the carbide slag. The modified carbide slag releases the organic substances whose combustion leads to a drop in CO2 capture capacity. The pre‐calcination treatment of the modified carbide slag at 400 °C before the first calcination was employed to avoid the combustion of the organic substances. The pre‐calcined modified carbide slag exhibits higher carbonation conversions, compared with the modified carbide slag without pre‐calcination treatment. The pre‐calcined modified carbide slag achieves higher carbonation conversions at 950 °C and shows larger surface area and pore volume than the modified carbide slag in the cycles. It indicates that combining the modification by pyroligneous acid with the pre‐calcination treatment apparently improves cyclic CO2 capture capacity of the carbide slag in the multiple cycles. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.