Investigation To Performance Of A Gas Turbine-Based Energy Supply System With Compressor Bypass Air Extraction For Energy Storage

With the development of China's economy,the energy consumption has been increasing,and the power production Pattern has always been optimized.Gas turbine distributed energy supply system has broad prospects with so many advantages such as environment-friendly,safe and reliable.However,due to the fluctuation of demand-side load and other factors,it is difficult to achieve supply-demand balance efficiently and flexibly under all operating conditions,so the thermal power ratio of operation is low,and the comprehensive energy efficiency is far from its rated value.Based on this,the Paper proposed a gas turbine energy supply system and system operation control method for compressor byPass extraction air energy storage.With the analytical solutions for gas turbine Part-load performances,the performance of CHP system was explored based on the control strategy of compressor byPass extraction air storage/release energy.Taking a daily demand-side power distribution with delay-step function as a case study,the influences of the peak-valley ratio and load frequency on system caPacities and power efficiency were studied.The analysis indicates that,compressor byPass air extraction results in an increment in air mass flow rate,and a considerable reduction in compression ratio.And also,the anti-surge performance of compressor and the off-design performance of gas turbine can be improved.The turbine can technically operate under constant exhaust temperature within the range of air extraction rate 0.3.The gas turbine Part-load performance is inferior to the reference one,whereas has advantages in higher exhaust temperature.In the process of gas storage,with the increase of pumping coefficient,the flow area increases gradually and the throttling loss increases first and then decreases.In the process of gas release,the larger the flow rate and the higher the temperature,the more power is done.The air turbine can exPand the maximum output of the energy supply system,which is related to the design Parameters of the turbine.In this Paper,the rated power of the gas turbine is designed to114.6%.When the relative power of the gas turbine is reduced to 50% of the rated power,the relative efficiency of the waste heat boiler in the exhaust system is about 92.5% and that in the reference system is about 85%.The heat-power ratio is exPanded to 1.47 and 1.147 times of the rated value respectively,so the recovery rate of waste heat in the exhaust system is higher.Under the design condition of air turbine,when the gas load is 50%,the relative energy efficiency of CHP system is 92% and 89% in the pumping system and the reference system respectively.At peak-valley of 3 and valley load frequency of 0.375,gas turbine caPacity can be designed as 4048 kW to meet the peak power load of 4600kW;the power efficiency increment reaches 2.02 per cent.It is proposed that solar-energy storage be further introduced for increasing the inlet temperature of air turbine,in aim to enhance the system efficiency and flexibility.