Energetische und wirtschaftliche Optimierung eines membranbasierten Oxyfuel-Dampfkraftwerkes
Jülich / Forschungszentrum Jülich, Zentralbibliothek (2015) [Book, Dissertation / PhD Thesis]
Page(s): IV, 337 S. : Ill., graph. Darst.
Carbon capture and storage is one technological option for reducing CO2 emissions. The oxyfuel process is based on the combustion of fossil fuels in an oxygen-flue gas atmosphere with the subsequent concentration of CO2. The oxygen is produced by cryogenic air separation with an energy demand of 245 kWhel/tO2. The application of ceramic membranes has the potential to reduce the specific energy demand of oxygen supply with consistently high-purity oxygen.This work focuses on • determining the efficiency of an advanced oxyfuel steam power plant that can be constructed today using membranes for oxygen production, • investigating and quantifying the potential for energy optimizing the overall process by changing its flow structure, • assessing the feasibility of individual optimization options based on their investment costs under market conditions.For this work, a method developed by Forschungszentrum Jülich and patented on 25 April 2012 under EP 2214806 is used. The Oxy-Vac-Jül concept is integrated into the oxyfuel steam power plant with simple process management using standardized power plant components. The net efficiency of the base power plant is 36.6 percentage points for an oxygen separation degree of 60 %. This corresponds to a net power loss of 9.3 percentage points compared to the reference power plant without CO2 capture. The specific electricity demand of this oxygen supply method is 176 kWhel/tO2. To increase the efficiency, the flow structure of the base power plant is optimized using industrially available components from power plant and process engineering. The 22 analyzed optimization options consist of design optimization of the gas separation process, the modification of the flue gas recirculation and the plant-internal waste heat utilization. The energetic advantage over the base power plant, depending on the optimization option, ranges from 0.05 - 1.00 percentage points. For each optimization option, the size and cost of the power plant components is calculated.The optimization options are assessed using an investment, efficiency and power-related factor. The assessment factor for the majority of optimization options is € 20 - 54 / kWgross per percentage point of increase in net efficiency. The levelized costs of electricity generation (LCOE) for these optimization options are € 0.027 - 0.073 / kWhel.The results of this study provide a basis for decisions on the application of optimization options in low-CO2 membrane-based oxyfuel power plants.