Techno-Economic Analysis of Lignite Fuelled IGCC with CO2 Capture: Comparing Fluidized Bed and Entrained Flow Gasifiers

Abstract

Integrated coal gasification combined cycle (IGCC) plants with pre-combustion capture of CO2 represent one of the most promising options for generating low-cost decarbonized power using bituminous coals. This work systematically quantify the effect of coal rank on the efficiency and economics of IGCC systems with CO2 capture and storage (CCS), with a special focus on comparison of systems using fluidized-bed gasifier (U-GAS) and entrained flow gasifier (Shell). It was found that the Shell IGCCs are little affect by low rank coal after pre-drying in terms of thermal efficiency and the levelized cost of electricity (LCOE) is only increase by 2–6% for lignite cases with and without CCS compared with bituminous coal cases. The specific CO2 emissions of U-GAS gasifier based lignite fuelled IGCC with CCS is 198 g/kWhe, almost two times of shell gasifier cases, mainly due to lower carbon conversion in the gasifier and the higher methane in the raw gas of gasifier. However, the total capital cost and COE of U-Gas IGCCs are 15–20% less than that of Shell IGCCs because of lower capital cost of gasifier, coal drying units and air separate units per kWe.