Integrated Gasifier Combined Cycle Plant with Integrated CO2 – H2S Removal: Performance Analysis, Life Cycle Assessment and Exergetic Life Cycle Assessment

Abstract

The aim of this study is to assess the possibility of reducing CO2 emissions from an Integrated Gasifier Combined Cycle plant, accounting for the entire life cycle.

With respect to the basic scheme of a conventional Integrated Gasification Combined Cycle - which already includes H2S removal - a shift reaction section followed by CO2 chemical absorption have been added, before the syngas combustion, in order to obtain a clean and H2-rich synthesis gas.

The proposed plant reaches 38.8 % efficiency vs. 46.4 % efficiency of the corresponding IGCC without CO2 removal. The main reason for the efficiency reduction is the complexity due to the addition of shift and CO2 removal sections and, hence, the related losses in the complex heat recovery process.

From LCA results, a substantial decrease in the carbon dioxide total production, due to the applied removal technology, is highlighted. In fact, the CO2 equivalent production in the life cycle, per energy unit, is one order of magnitude lower with respect to the parent IGCC.

Moreover, the major contribution to CO2 production comes from operation/maintenance phase; likely, in the case of Exergetic Life Cycle Assessment: the major exergy destruction - in term of MJ of destroyed exergy per functional unit - comes from operation/maintenance, which is two orders of magnitude greater than the contributions of the other phases.

The whole cycle has been simulated by means of Aspen Plus 10.1-0.

Keywords

• IGCC (integrated gasification combined cycle), CO2 removal, LCA (life cycle assessment), ELCA (exergetic life cycle assessment), ammine, GHGs (greenhouse gases)