No abstract

Integrating a power plant with CO2 capture incurs serious efficiency and energy penalty due to use of energy for solvent regeneration in the capture process. Reducing the exergy destruction and losses associated with the power plant systems can improve the rational efficiency of the system and thereby reducing energy penalties. This paper presents steady state simulation and exergy analysis of Supercritical coal-fired power plant (SCPP) integrated with post-combustion CO2 capture. The simulation was validated by comparing the results with a greenfield design case study based on a 550 MWe SCPP unit. The analyses show that the once-through boiler exhibits the highest exergy destruction but also has a limited influence on fuel-saving potentials of the system. The turbine subsystems show lower exergy destruction compared to the boiler subsystem but more significance in fuel-saving potentials of the system. Four cases of the integrated SCPP-CO2 capture configuration was considered for reducing thermodynamic irreversibilities in the system by reducing the driving forces responsible for the CO2 capture process: conventional process, absorber intercooling (AIC), split-flow (SF), and a combination of absorber intercooling and split-flow (AIC+SF). The AIC+SF configuration shows the most significant reduction in exergy destruction when compared to the SCPP system with conventional CO2 capture. This study show that improvement in turbine performance design and the driving forces responsible for CO2 capture (without compromising cost) can help improve the rational efficiency of the integrated system.

No abstract

Advanced coal-based power generation systems such as the British Coal Topping Cycle offer the potential for high-efficiency electricity generation with minimum environmental impact. An important component of the Topping Cycle program is the gas turbine, for which development of a combustion system to burn low calorific value coal derived fuel gas, at a turbine inlet temperature of 1260°C (2300°F), with minimum pollutant emissions, is a key R&D issue. A phased combustor development program is underway burning low calorific value fuel gas (3.6-4.1 MJ/m3) with low emissions, particularly NOx derived from fuel-bound nitrogen. The first phase of the combustor development program has now been completed using a generic tubo-annular, prototype combustor design. Tests were carried out at combustor loading and Mach numbers considerably greater than the initial design values. Combustor performance at these conditions was encouraging. The second phase of the program is currently in progress. This will assess, initially, an improved variant of the prototype combustor operating at conditions selected to represent a particular medium sized industrial gas turbine. This combustor will also be capable of operating using natural gas as an auxiliary fuel, to suit the start-up procedure for the Topping Cycle. The paper presents the Phase 1 test program results for the prototype combustor. Design of the modified combustor for Phase 2 of the development program is discussed, together with preliminary combustion performance results.

No abstract