Process Optimization in Postcombustion CO_2-Capture by means of Repowering and Reversible Carbonation/Calcination Cycle

摘要

Coal is the major power generation fuel for electricity production. Many countries are heavily dependent on coal, that contributes to about 30% of the European power generation and plays an important role in the European generation industry. The existing coal power plants must be operative to provide energy and take advantage of local resources, but it is necessary to reduce their CO_2 emissions in a feasible manner. It means without introducing excessive economic penalty or reducing their capacity and efficiency. In order to achieve this objective two strategies are highlighted, increase powt plant efficiency and capture CO_2 emissions. Increasing power plant efficiency is one of the less expensive ways to reduce CO_2 emissions however it is neither an easy task for existing power plant nor efficiency improvements are large enough to achieve important CO_2 emissions reduction. One of the best methods to significantly increase plant efficiency and also energy production from an economic standpoint is repowering. On the other hand, it is generally accepted that postcombustion CO_2 capture is one of the best suitable technologies for existing coal power plants. It is also well-know that one of the most important gaps in postcombustion capture is the necessity of achieve a process optimization for large-scale power plants. One of these technologies involves the separation of CO_2 from high temperature flue gases using the reversible carbonation reaction of CaO and the calcination of CaCO_3. In order to achieve a significant abatement of CO_2 emissions without excessive penalty in power plant efficiency, generating capacity and with CO_2 capture cost below 25 €/Ton CO_2, this paper proposes a new, feasible approach to join these two concepts by an optimal integration of the processes within an existing power plant.