CO2 capture with calcined dolomite: the effect of sorbent particle size

Abstract

This investigation is set in the more comprehensive study of an innovative fluidized bed reformer configuration for producing hydrogen from either biomass/coal syngas or natural gas, in which capture of carbon dioxide by-product occurs in parallel with steam reforming and water–gas shift reactions. Reported here are experimental data of carbon dioxide absorption by particles of calcined dolomite included in a bed of otherwise inert material; the bed, initially fluidized by nitrogen, was subjected to a step concentration input of carbon dioxide and the sorption kinetics was obtained from the outlet response of the entire system. The influence of dolomite particle size was investigated—from 98 to 1,550 μm—and a previously developed grain model was used to relate the observed effect of particle diameter to the complex mechanism of carbon dioxide capture in a solid sorbent. The results show that pore shrinking effects during the carbon dioxide capture process become increasingly more significant as the particle size is increased.