Research on the coal-fired cogeneration unit's performance evaluation technique

In a large energy unit that burns coal, the regenerative stages change greatly affects the economic efficiency of the unit. For researching such influential degree in all round, the paper established a quantitative analysis model on the economic efficiency affected by the change of the regenerative stages of turbine in an energy unit that burns coal. Using a 600MW unit as the subject of the study, the paper quantitatively analyzed the effect of the change of the regenerative stages of a turbine on the rate of heat consumption, boiler efficiency, the electricity consumption rate of the power plant and the standard coal usage rate for electricity generation under different conditions. It is shown by the research that, when one steam extraction phase is added before the fourth stage of the low-pressure stage of turbine, the unit economic efficiency is the best. In addition, under the respective condition of 100%THA, 75%THA, 50%THA and 40%THA, the standard coal burn rate for a unit power supply can be lowered to 0.78 g/(kW•h), 0.78 g/(kW•h), 0.84 g/(kW•h) and 0.75 g/(kW•h) respectively. The research may supply a conceptual guidance for the optimal design and operation of the change of a regenerative system in a coal-fired power unit.