CO2 capture using calcium oxide under biomass gasification conditions

Abstract A laboratory scale CO 2 capture apparatus was designed, fabricated, and tested for performing CO 2 capture via carbonation of fine calcium oxide (CaO) with particle size in micrometers. This apparatus included a fixed-bed reactor made of stainless steel (12.7 mm in diameter and 76.2 mm long) packed with CaO particles dispersed in sand. The reactor was heated and maintained at isothermal conditions (500–595 °C) during each experiment. The pressure along the reactor was kept constant using a back pressure regulator. The conditions of the experiments were relevant to biomass gasification with in situ CO 2 capture. 1% CO 2 in 99% N 2 flowed through the reactor at a flow rate of 150 ml/min (at standard conditions). The CO 2 percentage of the outlet gas stream was measured by using a CO 2 analyzer and was used to calculate the conversion of CaO. The results indicated that the rate of CaO carbonation considerably increased with reactor temperature increasing from 500 °C to 595 °C. The conversion rates of CaO carbonation were well fitted to Lee's and Shih's models for CO 2 capture in dry and moist stream, respectively.