AMANN J. M. 1, DESCAMPS C. 1, KANNICHE M. 2, BOUALLOU C. 1* (1)CENTRE ÉNERGÉTIQUE ET PROCÉDÉS (CEP), ECOLE NATIONALE SUPÉRIEURE DES MINES DE PARIS, 60, BOULEVARD SAINT MICHEL, 75006 PARIS, FRANCE. TEL: 33 140519111, EMAIL: CHAKIB.BOUALLOU@PARIS.ENSMP.FR (2)EDF, RESEARCH AND DEVELOPMENT DIVISION, POWER GENERATION T
The aim of this study is to assess the energy consumption when an amine process of CO2 capture is integrated downstream from a power plant. We simulated, with the software Aspen plus™, the CO2 capture of two types of power plants: the first one, a Natural Gas Combined Cycle (NGCC) and the other one a Pulverised Coal Fired power plant (CF). For the first type of flue gas, the CO2 concentration is about 5 % mol and about 12 % mol for the second. Two amines solutions were used: monoethanolamine (MEA) and methyldiethanolamine (MDEA). The amine concentration in the aqueous solvent ranges from 10 to 30 % by wt. for MEA and from 30 to 50 % by wt. for MDEA. The CO2 loading in the lean solvent varies from 0.1 to 0.3 mol/mol for MEA and from 0.01 to 0.08 for MDEA. The results show that the more the flue gas is concentrated out of CO2 the less the energy consumption per ton of captured CO2 is high. Thus the CO2 recovery will have a higher impact on the net power output of a NGCC than on the net power output of a CF. Moreover, although MDEA is easier to regenerate than MEA, an aqueous solvent of 50 % by wt. MDEA is not adapted to CO2 absorption. The main explanation is that the solvent flow is higher even with a high concentration in MDEA. Additionally the kinetics of CO2 absorption with MDEA is lesser favorable than with MEA. This means that the installation size will be bigger and thus its capital expenditure more expensive.