Dolomite study forin situCO₂capture for chemical looping reforming

Abstract

The non-isothermal kinetic and thermal behaviour of a naturally formed dolomite in conditions that approach in situ CO2 capture in chemical looping reforming, were investigated. The performance of this dolomite was studied at micro-scale in 'dry' conditions, as well as at macro-scale in 'dry' and 'wet' conditions to investigate the effects of scale (3 mg, 2.5 g), partial pressures of CO 2 (< 15 kPa) and steam, and deactivation upon limited cycling. The carbonation and calcination kinetics were modelled using an improved iterative Coats-Redfern method. Increasing CO 2 partial pressures on the 'dry' macroscale exacerbated the experimental carbonation conversions in an inversely proportional trend when compared with those at micro-scale. The presence of steam had a positive effect on CO 2 chemisorption. Steam had a negligible influence on the calcination activation energies. The activation energies of carbonation were increased for the experiments at the highest CO 2 partial pressures under wet conditions.

110th Anniversary: Carbon Dioxide and Chemical Looping: Current Research Trends

“…One drawback of this process is that the resulting CO 2 is diluted with (oxygen-depleted) air. The overall reaction then corresponds with eq . In summary, this process combines chemical looping combustion (eqs and ) with steam re-forming (eq ), water–gas shift reaction (eq ), and chemical looping carbon dioxide capture (eqs and ). Following this patent, much effort has been put into studying this processlater termed sorption enhanced chemical looping re-forming experimentally. − In 2010, Abanades and co-workers proposed a variant of this process (Figure ) to overcome the drawback of CO 2 dilution . As a first step, they propose sorption enhanced steam re-forming using a (promoted) copper catalyst (eqs –).…”