Optimization Research Of Operational Parameters Of Condensing Turbine

With the energy crisis and intensifying electricity market competition, it hasgreat significance for improving the efficiency of energy conversion and ensuring theeconomical operation of power plant to enhance the competitive ability of electricpower industry. The unit operation parameters are among the important factorsaffecting the thermal efficiency. It is therefore essential to thoroughly research intothe optimization of operation parameters in order to save energy and reduceconsumption.Taking NZK600-24.2/566/566and N600-16.67/537/537unit as the example, theoff-design algorithm of the steam turbine, the cold-end system and feed water systemis determined basing on the effect of steam distribution modes, environmentalcondition and cooling water temperature. With the minimum unit heat rate, themaximum difference between unit power generation and fan (or circulating waterpump) power consumption and the maximum power supply efficiency as theobjective function, the model of the operation parameter optimizing of live steampressure, exhaust steam pressure and multi-variable effect is built using theoff-design and modified particle swarm optimization algorithm, in order to determinethe optimal operation parameters.For direct air-cooled unit, the results indicate that, in the live steam pressureoptimization, the optimal live steam pressure is higher than the design andexperiment value at the same load and constant pressure operation should be adoptedwhen the load is above about82%of the rated load. In the exhaust steam pressureoptimization, both the optimal speed of the fan and exhaust pressure increase as theunit load or the wind speed or ambient temperature rises, or decrease otherwise.Moreover, the influence of ambient temperature on the exhaust pressure becomesgreater when the temperature gets above20℃, and part of the fans need to be shutdown at certain low loads if the temperature falls below-10℃. What’s more, thewind direction also has effect on the optimal exhaust steam pressure, the optimalspeed of the fan under the prominent wind direction is lower than that of otherdirections. In the operation parameter optimization of multi-variable influence, theoptimal live steam pressure, exhaust steam pressure, fan speed and extraction steampressure will increase as the unit load or ambient temperature increases. The powersupply efficiency decreases when the wind speed or ambient temperature increases atthe same load. For water cooling unit, the results indicate that, the optima l live steam pressure, exhaust steam pressure, the speed of circulating water pump and feed waterpump will increase as cooling water temperature rises at the same load in thecalculation of operation parameter optimization of multi-variable influence.Meanwhile, the power supply efficiency will decrease due to the increasing powerconsumption of circulating water pump. Consequently, the analysis provides areliable reference for optimizing operation of the units.