Static-state Characteristics Study On IGCCsystem With CO₂Removal Process

As the main greenhouse gas, CO2plays an increasing impact on the globalwarming, and makes the CO2removal of coal-fired power plant attracts moreconcern in the field of power generation. As an advanced clean coal combustionsystem, IGCC can be combined with CO2removal process so as to achievenero-zero emissions of pollutants. Based on Aspen Plus software, a200MW-classIGCC coal-water slurry gasification system with CO2removal process is establishedin this paper, and this system is studied and analyzed in this paper.Firstly, the model of gasifier and gas turbine are established. For gasifier, theinfluence of carbon conversion and heat loss to the gasifier outlet gas parametersisanalyzed. Change the amount of coal or oxygen are two method to satisfy theoff-design characteristics, and a comparison of the two method iscalculated in thispaper. The gas turbine model is established based on the design parameters of GE9E gas turbine, and fueled with natural gas, low calorific value coal syngas andhydrogen were compared, off-design conditions were analyzed in the way ofconstant IGV.The model of a200MW-class IGCC system with and without CO2removalprocess is the basis of analyzing the IGCC system. Based on the sub-unit model ofIGCC, we complete the modeling of the overall IGCC system. With a low NOxemissions and economic requirements of gas turbine combustor, the air of the gasturbine compressor will inject to air sepration unit(ASU), and N2from ASU willreinjection to gas turbine, so we calculated for the best N2rejection rate. Aftercalculation, we found the IGCC system with and without CO2removal process hasthe highest efficiency with0.96and0.86N2rejection rate separately.The twosystems are compared with a settled N2rejection rate and found that the generationpower of IGCC with CO2removal is0.47%lower than IGCC without CO2removal,and the efficiency of power supply decreases3.42%.Finally, an off-design analysis and comparison was calculated on IGCC withand without CO2removal, after the calculation of80%-90%load conditions ofIGCC system, we found that, the paremeters of the two systems are decreased whilethe load reduced. When the load is80%, the generation power of IGCC with CO2removal will reduced to80.1%of100%load, and the power supply will be74.9%of100%load; the generation power of IGCC without CO2removal will reduced to80.7%of100%load, and the power supply will be78.0%of100%load.