CO2 capture using calcium oxide under biomass gasification conditions

A laboratory scale CO2 capture apparatus was designed, fabricated, and tested for performing CO2 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 degrees 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 CO2 capture. 1% CO2 in 99% N-2 flowed through the reactor at a flow rate of 150 ml/min (at standard conditions). The CO2 percentage of the outlet gas stream was measured by using a CO2 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 degrees C to 595 degrees C. The conversion rates of CaO carbonation were well fitted to Lee's and Shih's models for CO2 capture in dry and moist stream, respectively. (C) 2014 Elsevier Ltd. All rights reserved.