An operational approach for the designing of an energy integrated oxy-fuel CFB power plant

Abstract

Oxy-fuel combustion is one of the key alternatives for coal power production with near-zero CO 2 emissions. Technology has been successfully proved in demonstration facilities and the next step is to improve its efficiency to facilitate the application to future commercial installations. The use of pure oxygen reduces the total volume of flue gases and concentrates CO 2 at boiler outlet. Nevertheless, there is an important energy penalty and efficiency of the power plant substantially decreases around 10-12 efficiency points. Increasing the oxygen concentration in the boiler up to 40% is a recent proposal to raise boiler efficiency and it is also an interesting solution to overcome the energy penalties of the kind of CCS system. Air separation unit (ASU) and compression and purification unit (CPU) are the main processes that reduce the efficiency. Heat integration results mandatory in order to improve the overall power plant efficiency by reducing the energy penalty. Many solutions have tried to show outstanding efficiency results but practical proposals are necessary to develop the technology. The use of flue gases waste energy to recycle flue gases heating up, oxygen preheating and increasing temperature of feedwater to steam cycle has been proposed to surpass the efficiency reduction. Nevertheless, care should be taken as potential problems would appear if only theoretical analysis is carried out. This work deals with a suitable and flexible design to increase the overall efficiency of a second oxy-fuel combustion power plant working with high O 2 concentration. Waste energy has been integrated avoiding any potential risk/damage into a new designed steam cycle. Finally, results are compared with a previously optimized power plant design without operational restrictions and just a slight reduction in power plant net efficiency (less than 1%) was observed between both concepts.

From O2/CO2 to O2/H2O combustion: The effect of large steam addition on anthracite ignition, burnout and NOx formation

“…Main challenges for the development of oxy-fuel combustion plants are related to the reduction of the large energy penalties caused by ASU and CPU stages (air separation unit and compression and processing unit, respectively), with a target of 7-9 % [7]. Besides energy integration and optimization, other solutions can also contribute to increase the efficiency and operating manageability of these plants.…”

Thermodynamic Analysis and Optimization of an Oxyfuel Fluidized Bed Combustion Power Plant for CO2 Capture

“…In most literature, the typical CO 2 pressure and temperature ranges are 8–20 MPa and 0–50 °C, respectively, ,, and the compression ratio is usually in the range of 1.6–2.4. ,, In this work, CO 2 is compressed to 15 MPa and is ready for delivery and storage. The compression process includes six stages, as shown in Figure .…”

“…Kotowicz et al showed that the efficiency penalty was reduced to 7.3% after heat recovery from an ASU and the exhaust flue gas. Espatolero et al recovered the heat from an ASU and a flue gas compression and purification unit (CPU), and the net electric efficiency was increased by approximately 3% without operational restrictions.…”

"Паровой Электрообогреватель Низкого Давления"

“…Рассмотрены проблемы развития систем теплоснабжения [10], где одним из вариантов для создания автономных систем отопления является использование электрического тока. Имеются также ряд зарубежных публикаций, направленных на создание новых источников тепла и повышение эффективности работы систем отопления [11][12][13]. Исследования основаны на использовании известных методов и законов теории теплообмена [14,15].…”