Study On The Peak Shaving Characteristics And Thermal Economy Of The GTCC Based CHP System Under Overall Operating Conditions

In order to achieve the goal of "peak carbon dioxide emission and carbon dioxide neutral",on the one hand,the proportion of renewable energy generation should be increased.However,renewable energy has the characteristics of intermittence and volatility,which puts forward higher requirements for the peak shaving capacity of the power station.Gas turbine combined cycle(GTCC)has the advantages of strong peak shaving capacity and low pollutant emissions.On the other hand,the comprehensive energy utilization efficiency of the power system should be improved.The combined heating and power(CHP)system is more and more widely used in the energy field because of its high comprehensive energy utilization efficiency.The GTCC based CHP system is more and more widely used.The GTCC based CHP system is usually in the"ordering power by heat" operation mode.This operation mode will greatly reduce the peak shaving capacity of the GTCC based CHP system affected by the strong coupling characteristics of heat and power.This paper aims to improve the peak shaving performance of GTCC based CHP system under overall operating conditions.By establishing the off-design operating condition calculation model of the GTCC based CHP system,the operating characteristics under different environmental conditions and different heating and power load demands are studied.The specific research contents are as follows:The off-design simulation model of the GTCC based CHP system is established.Based on the principle of "Temperature matching and cascade utilization" of the total energy system,the exhaust gas from the heat recover steam generator(HRSG)is used to heat the compressor inlet air,and a new regenerative cycle is formed in the GTCC based CHP system.At the same time,according to the operation characteristics of the new system,a new heat and power load regulation mode is proposed.Based on the calculation model of the GTCC based CHP system,the key thermodynamic parameters of the CTCC based CHP system and the changes of the heat and power operation region are studied,and the influence of the compressor inlet air temperature regulation mode on the peak shaving performance of the GTCC based CHP system on the heating characteristic day is analyzed.The results show that the CTCC based CHP system adopts the compressor inlet air heating(CIAH)mode,and the new energy integration is increased by 252.15MW,380.17MW,300.8MW and 239.96MW respectively on the heating characteristic days from heating period 1 to period 4.The technical and economic results indicate the annual net income of the GTCC based CHP system is increased by 181.83×104$.The dynamic investment return period of the CIAH mode is 3.3 years.The method of gas turbine interstage extraction(GTIE)heating the high-pressure superheater and reheater to improve the peak shaving performance of the GTCC based CHP system is proposed.Based on the off-design load regulation operation strategy of the compressor inlet guide vane(IGV),the influence of conventional operation mode and GTIE mode on energy distribution of the system is studied,and the peak shaving characteristics and economy of the GTCC based CHP system under GTIE mode are analyzed.The results show that in the whole heating season,the integration of new energy is increased by 72071 MW and the consumption of natural gas is decreased by 861.74×104m3,profit of the system is decreased by 4.72 ×105$.As the price of natural gas rises,the benefits of GTIE mode are more obvious than that of conventional operation mode.In order to significantly improve the peak shaving performance of the GTCC based CHP system,the collaborative operation performance of CIAH mode,GTIE mode,and back pressure(BHP)mode is studied.The multiple-mode collaborative operation strategy not only solves the problem of the compressor inlet temperature limitation of the single CIAH mode at high heat load,but also solves the problem of the single GTIE mode,which does not significantly improve the peak shaving capacity of the GTCC based CHP system at low load.At the same time,the multiple-mode collaborative operation strategy solves the problem of the single back pressure heating mode does not have the peak shaving capability.The paper analyzes the impact of adopting multiplemode collaborative operation strategy on the peak shaving performance of GTCC based CHP system during heating characteristic days.The results show that the new energy integration is increased by 115713MW and natural gas consumption is decreased by 22.1×106m3 during the whole heating season by adopting the multiple-mode collaborative operation strategy,the profit of the system is increased by 2.7 × 106$.The dynamic payback period of the multiple-mode collaborative operation strategy is 5.3 years.From the perspectives of increasing the integration of renewable energy,natural gas consumption,economy,and technological economy,the performance of the multiplemode collaborative operation heat-power decoupling strategy and traditional heat-power decoupling technology(including electric boiler mode and heat storage tank mode)is compared and analyzed.The results show that in the whole heating season,the integration of new energy is increased by the multiple-mode collaborative operation strategy,electric boiler technology and heat storage tank technology respectively 1.16×105MW,1.37×105MW and 5.65×104MW.When the objective power load is 197.5MW,the integration of renewable energy of the heat storage tank technology is increased from 770.18MW to 1.43×105MW compared with the multiple-mode collaborative operation strategy.Compared with the multiple-mode collaborative operation strategy,the fuel saving of electric boiler technology is increased from 18.86 × 106m3 to 25.93×106m3.