A thermodynamic analysis of optimization schemes for a heat-power cogeneration system

摘要

To overcome the strong thermoelectric coupling in a coal-fired combined heat and power plant (CCHPT), three optimization schemes are investigated. These include low-pressure turbine little steam operation (LLPEH), extracting steam from high pressure turbine (HP-LPEH), and integrating the LLPEH and HP-LPEH (HP-LLPEH). These are employed for enhancing the plant's heat and electricity supply flexibility using steam extracted between the intermediate- and low-pressure turbines to provide heat (LPEH). The thermodynamic and economic performance of the schemes when applied to a 330MW coal-fired combined heat and power plant were evaluated and compared. The comparison reveals the highest heat supply capacity, highest heat to electricity ratio, and lowest standard coal consumption for the HP-LLPEH scheme, while the LPEH exhibits the highest thermal efficiency.