Modeling the Performance Characteristics of Diesel Engine Based Combined-Cycle Power Plants—Part II: Results and Applications

In this two-part series publication a mathematical model of the energy conversion process in a diesel engine based combined-cycle power plant has been developed and verified. The examined configuration consists of a turbocharged diesel engine (the topping cycle), a heat recovery steam generator (HRSG) and a steam turbine plant (the bottoming cycle). The model is then used to provide an analysis of performance characteristics of the combined-cycle power plant for steady-state operation. Numerous practical performance parameters of interest have been generated, such as the mean indicated pressure, specific fuel consumption, hourly fuel consumption, brake horsepower of diesel engine, mass flow rate, pressure, and temperature of gases and air, respectively, through the gas turbine and compressor (in the frame of a turbocharger), temperature of flue gases at boiler inlet and outlet, mass flow rate of exhaust gases through the convection coils, and mass flow rate, temperature, pressure, and enthalpy of superheated steam. The performance maps have been derived. The effect of change in the major operating variables (mutual operation of diesel engine, HRSG, and steam turbine) has been analyzed over a range of operating conditions, including the engine load and speed. The model is used as a desktop design tool for accurate predictions of cycle performance, as well as insight into design trends.