IGCC Modelling for Simultaneous Power Generation and CO₂ Capture

Power producing industry has largely relied on coal as a fuel source and will continue to depend on it for coming decades. However, to address the global warming problem while keeping high efficiency and economic feasibility of the processes is a key challenge. Coal-based power plants with post-combustion capture tend to have lower capital costs and cost of electricity without capture. On the other hand, pre-combustion capture plants tend to be less expensive when current CO₂ capture systems are added. This analysis suggests that pre-combustion plants can be an attractive option for the power generation if carbon capture and storage (CCS) technology is implemented on a large scale. This paper is focused on the in depth modeling and simulation of integrated gasification combined cycle (IGCC) with CO₂ capture using a physical solvent. Three case studies have been developed to analyze the overall plant output with CO₂ capture. In order to ensure a fair evaluation of analysis, a consistent and transparent methodology has been followed for all the cases. First two cases use the water gas shift reactions scheme with sour shift catalysis process. The resulted syngas free of CO₂ can either be combusted by using air or O₂. The first case uses air as an oxidant for burning H₂ and the combustor temperature is controlled by air as well. In the second case, O₂ is used as an oxidizing agent in the H₂ combustion. However, combustion temperature control is achieved by recycling the captured CO₂. In the third model, WGS reactor has been removed. The syngas composed of CO and H₂ is sent directly for combustion which makes it similar to the oxy-fuel combustion process. In this way, captured CO₂ can be recycled back to control the combustor temperature in 2^nd and 3^rd case. The results show that the overall plant output power for the three cases is 378MW, 344MW and 388MW respectively. Case 1 and 3 are the competitive options in terms of efficiency; however the capital cost may be the deciding parameter.