Modeling of oxy‐combustion flue gas desulfurization by seawater absorption

Abstract

AbstractCombustion of sulfur and sulfur compounds present in fuels such as coal or natural gas (NG) results in the formation of SO2. The main objective of this study was to find a suitable flue gas desulfurization process for two oxy‐combustion power plants fired with either NG (467 MW) or pulverized fuel (PF) (596 MW) with emitted flue gas containing 163 and 896 ppm of SO2, respectively. Flue gas after further treatment can be compressed, liquefied, and employed for enhanced oil recovery (EOR) or stored in an aquifer.Seawater flue gas desulfurization (SFGD) has been adopted as the removal process in this study, and the emissions levels, energy requirement, and seawater usage were calculated and reported. SO2 concentration target in the desulfurized flue gas, containing mainly CO2, has been set to 30 ppm. Gas is compressed up to 20 atm prior to desulfurization; the result was a significant reduction in the size of the desulfurization plant.Simulations for the NG‐fired flue gas suggest that the desulfurization process requires 0.6 kg of seawater and 257 kJ per kg of compressed and desulfurized CO2.Simulations for the PF‐fired flue gas suggest that the desulfurization process requires 13.2 kg of seawater and 318 kJ per kg of compressed and desulfurized CO2.Power plant output after compression to 20 atm and desulfurization is 453.8 MW (2.8% reduction in plant power output) for the NG‐fired case and 553.8 MW (7.1% reduction) for the PF‐fired case.Lime addition effect on the reduction of the total amount of seawater utilized for SO2 removal has been investigated for the latter case. © 2008 American Institute of Chemical Engineers Environ Prog, 2009