Integration of CO2 capture and mineral carbonation by using recyclable ammonium salts

Abstract

A new approach to capture and store CO2 by mineral carbonation using recyclable ammonium salts was studied. This process integrates CO 2 capture with mineral carbonation by employing NH3, NH4HSO4, and NH4HCO3 in the capture, mineral dissolution, and carbonation steps, respectively. NH 4HSO4 and NH3 can then be regenerated by thermal decomposition of (NH4)2SO4. The use of NH4HCO3 as the source of CO2 can avoid desorption and compression of CO2. The mass ratio of Mg/NH 4HCO3/NH3 is the key factor controlling carbonation and the optimum ratio of 1:4:2 gives a conversion of Mg ions to hydromagnesite of 95.5 %. Thermogravimetric analysis studies indicated that the regeneration efficiency of NH4HSO4 and NH3 in this process is 95 %. The mass balance of the process shows that about 2.63 tonnes of serpentine, 0.12 tonnes of NH4HSO4, 7.48 tonnes of NH4HCO3, and 0.04 tonnes of NH3 are required to sequester 1 tonne of CO2 as hydromagnesite. Breathe out later: A new approach to capture and store CO2 by mineral carbonation using recyclable ammonium salts is studied. The mass ratio of Mg/NH 4HCO3/NH3 is the key factor that controls carbonation (see image). The use of NH4HCO3 as the source of CO2 can avoid desorption and compression of CO2. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.