CO2 Emission Abatement From Fossil Fuel Power Plants by Exhaust Gas Treatment

Abstract

In this paper thermodynamical and economic analyses of fossil-fuel-fired power plants, equipped with systems for CO2 recovery, are presented. The investigation has been developed with reference to power plants representative both of consolidated technology (i.e., steam cycle and combined cycle power plants), and of emerging or innovative technology (integrated coal gasification combined cycle, IGCC, and advanced mixed cycle, AMC). There are two main methods to reduce CO2 from power plant flue gas: physical and chemical absorption. In this work chemical absorption and liquefaction of CO2 removed have been considered. With reference to thermodynamical and economic performance, significant comparisons have been made between the above introduced reference plants. An efficiency decrease and an increase in the cost of electricity has been obtained when power plants are equipped with CO2 removal systems and units for liquefaction of the removed carbon dioxide. The main results of the performed investigation are quite variable among the different power plants here considered: their efficiency decreases in a range of 6 percentage points to nearly 13, while the electricity production cost increases in a range of 25% until 72%. The AMC stands out among the other power plants here analyzed because, after CO2 recovery, it exhibits the lowest net work output decrease, the highest net efficiency and the lowest final specific CO2 emission. In addition to this, its economic impact is favorable when the AMC is equipped with systems for CO2 recovery. As a result it achieves a net electric efficiency of about 50% with a carbon dioxide emission of about 0.04 kg/kWh, and the electricity production cost rises to about 25% in comparison with an AMC without CO2 removal and liquefaction systems.