| In recent years,China’s economic and technology have been rapidly growth,while the importance to establish a environmental-friendly environment has been drawn more and more attention.Due to continuous efforts for using energy effectively in coal-fired power plants,according to the 13th Five-Year Plan,about 340 million kilowatts capacity of power plants have been retrofitted,which accounts for a quarter of the total capacity in China.Around 20 million kilowatts of capacity of power plants were closed.The plan of energy conservation,emission reduction and upgrading(2014-2020)pointed out that by 2020,the net coal consumption rate will recline to as low as 310 g of standard coal per kWh,achieving the goal of overall ultra-low emissions from the coal-fired power plants.In this paper,a thorough analysis for a power plant in hebei province of China with high coal consumption was carried out.Firstly,the data collected in this power plant were processed,including comparison of the overall energy consumption during operation hours,and the results showed that the power plant has potential to save energy.Secondly,models of major units of the power plant were established based on the design and experiment data in different loads,the simulation was verified by comparing with the results of thermal performance calculation,and the cause of the high energy consumption was determined.Finally,plans for energy saving of this power plant were proposed based on the former analyses,meanwhile,techno-economic analysis and the overall evaluation were adopted.The study carried out in this paper shows that the huge mount of air leakage from turbines shift seal is the main reason for the high energy consumption.Meanwhile,boiler and air condenser scarcely have influence on the energy consumption of the power plant.Through retrofitting the coupling of boiler and turbines,the coal consumption for power generation can be reduced by more than 0.66 g/kWh.However,the cost of this improvement is relative high,and the cost recovery efficiency is low,which means that the recovery time of the equipment will relative long.While,the plan of adding a peak condenser for energy saving is more efficiency,by which the exhaust pressure of the turbine’s low-pressure cylinder is reduced by an average of 8kPa,and the power generation coal consumption is reduced by about 7.11 g/kWh..The research methods and conclusions of this paper provide theoretical foundation for further study of energy saving retrofit in supercritical coal-fired air-cooling power plant,and has great realistic significance to the same kind of power plants for improvement. |
