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Thermodynamic and ecological assessment of selected coal-fired power plants integrated with carbon dioxide capture

Skorek-Osikowska, Anna, Bartela, Łukasz, Kotowicz, Janusz
Applied energy 2017 v.200 pp. 73-88
absorption, air, carbon dioxide, carbon sequestration, coal, combustion, gasification, greenhouse gas emissions, mathematical models, power plants, thermodynamics
The primary objective of the study presented in this paper was a thermodynamic and ecological analysis of coal-fired power plants integrated with carbon dioxide capture installations working in different technologies (pre-combustion, oxy-combustion and post-combustion) and a comparison of these systems with reference systems, i.e. ones not-integrated with CO2 capture. Calculations were performed using our own developed mathematical models for the integrated units. The article quantitatively demonstrates that the integration of a carbon dioxide capture installation with a power plant causes a significant decrease in the net power and efficiency in relation to the reference system (without capture). In the case of a conventional coal unit working in the post-combustion technology and integrated with an absorption CO2 capture installation and compression of carbon dioxide to 15MPa, the net efficiency decreases in relation to the reference plant by 11.75 percentage points. The oxy-combustion unit was characterized by a decrease in efficiency (in relation to the power plant operating in the air combustion technology not integrated with Carbon Capture and Storage (CCS) installation) equal to 7.85 percentage points. In the unit working in pre-combustion technology (Integrated Gasification Combined Cycle (IGCC) system) integrated with a membrane CO2 separation installation the efficiency decrease relative to the unit without capture was equal to 16.89 percentage points.The main advantage of those systems integrated with carbon dioxide capture installations is the significant reduction of emissions to the atmosphere (environmental effect). This effect significantly depends on the separation method and the obtained effect of separation. Implementation of the capture plant in the analyzed post-combustion system allowed for a reduction of the value of the average annual CO2 emission rate aggravating unit of net electricity produced from nearly 735kgCO2/MWh to 100.77kgCO2/MWh. In the case of the unit working in IGCC technology integrated with membrane CO2 capture, this rate was equal to 89kgCO2/MWh. The lowest value was obtained for the power plant working in oxy-combustion technology, for which the emission rate was obtained at 19kgCO2/MWh.