| Natural gas power generation has flexible start-up and shutdown,friendly load adaptability,which can meet the demand of rapid peak load regulation and frequency regulation of power grid,and help to improve the security of power grid.Meanwhile,as a kind of clean energy,natural gas power generation can effectively optimize and adjust the energy structure,and its proportion in China’s primary energy consumption is rising.It is estimated that by the end of 2020,the installed capacity of gas turbine in China will be high to110 million kilowatts.Therefore,it is of great practical significance to study the in-depth peak shaving capacity and energy-saving of gas-fired units.The exhaust gas temperature of waste heat boiler of 9F gas-fired unit is generally about90℃.The high discharge temperature not only wastes energy,but also causes serious environmental heat pollution.What’s more,the ambient temperature affects the output and efficiency of gas turbine.When the temperature rises,the air density and mass flow decreases,the power consumption of compressor increases and the output of combined cycle unit decreases.The hot water generated from waste heat of boiler can be used to drive lithium bromide cooling device,then the cooling capacity generated will be used to cool the intake air of compressor,thereby improving the output of gas turbine,ensuring the effective dispatch of the power grid and increasing electricity sales to obtain profits.From the perspective of engineering application,this paper studies the regulating characteristics of intake air temperature of AE94.3A gas-steam combined cycle co-generation unit.Through the analysis of the impact of ambient temperature on the economy of the combined cycle unit,the selection,installation and commissioning of the intake air temperature regulating device.Finally,the experimental results are analyzed to verify the correctness of the design.Through modeling and analysis,the highest point of efficiency is in the ambient temperature range of 25℃-27.5℃,which shows that the application of intake air cooling technology in large gas turbine unit is theoretically feasible in summer.In view of the fact that the annual average humidity of the power plant is about 80% and the temperature difference between dry bulb and wet bulb is small,lithium bromide absorption cooling device is selected,and 25℃ is taken as the reference point of intake temperature design.The operation process proves that the type selection completely meets the actual requirements of safety and economy.The results show that after the air intake cooling system putting into operation,the gas turbine intake temperature of the first unit decreases by 6.2 ℃,the combined cycle power supplyincreases by 10.408 MW,and the unit efficiency increases by 0.21%;the gas turbine inlet temperature of the second unit decreases by 7.38 ℃,and the combined cycle unit power supply increases by 15.006 MW,and the unit efficiency increases by 0.24%.After the intake cooling device is put into operation,the output of the combined cycle unit is increased,which is completely appropriate from the investment income.Through the above research,the engineering experience and regulating characteristics of the intake air temperature regulating device of large-scale F-class gas turbine unit are obtained,which provides guidance for the project promotion and economic operation of the device,and offers a new way to improve the profits of natural gas power generation operation. |
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