Study On Design Thermo-economics And Regulation Characteristics Of Compressor Bypass Extraction Air Energy Storage In Gas Turbine-based Energy Supply Systems

Distributed gas turbine-based energy supply systems are positively encouraged with the development of industrial zones.Gas turbine-based energy supply systems with the advantage of peak regulation,and energy storage systems with the merit in stabilizing renewable energy fluctuation,will together play an important role in promoting the consumption of renewable energy.Therefore,gas turbine-based energy supply systems,which fit in with the renewable energy prospect,are facing with the challenge of great flexibility,high efficiency and active load regulation.In this thesis,gas turbine-based CCHP(combined cooling,heating and power)system was taken as the research object;and the design thermo-economics and regulation characteristics of compressor bypass extraction air energy storage in the energy supply system were studied from the perspectives of:(1)design parameters configuration;and(2)operating flexibility and active load regulation.The work may provide theoretical basis and engineering practical reference for promoting the flexible load matching between the energy supply side and the demand side.In the study on design thermo-economics of energy supply system composed of a gas-steam combined cycle,the empirical coupling relation between the power efficiency of bottom cycle and the exhaust temperature of gas turbine was summarized through the design parameters of some practical in-service small and medium-sized gas turbine units.The thermo-economics analysis parameters and model were proposed suitably for the energy supply system.Using the proposed method,the influence of design parameters on the design performance of the energy supply system was obtained.To enhance the flexibility at the deep peak-load of energy supply system,a novel concept of energy regulation with CBAE(compressor bypass air extraction for energy storage)was put forward.With a stage-stacking method for compressor performance and the off-design performance analysis for gas turbine,comparative research was carried out on gas turbine par-load performance under constant exhaust temperature,and on the load characteristics of energy supply system under IGV(inlet guide vane)regulation and CBAE regulation.Further,in order to analyze the supply-demand coupling performance of energy supply system under different load regulation strategies,the design capacities of main components,including gas turbine,HRSG(heat recovery steam generator),Li Br/water absorption chiller and the energy storage system,were optimized and analyzed,where three different hourly load distributions were selected as demand-side cases,and the maximum overall energy efficiency was taking as the optimization target.The analysis indicates that,the concept of unit power deficiency coefficient by extraction steam in the thermal economic evaluation of gas turbine-based energy supply system obtains a concise and meaningful expression of overall energy efficiency.At a given designed heat-power ratio and heating parameters,compressor optimal pressure ratio at the maximum overall energy efficiency is considered equal to that at the maximum power efficiency of combined cycle.Improving turbine inlet gas temperature is an important direction for enhancing the thermal economy of the system.Gas turbine part-load power efficiency under CBAE regulation is inferior to that under IGV regulation,whereas the former ensures gas turbine a higher capacity of power and heating than the latter.Thus,CBAE regulation strategy greatly improves heat-power ratio and flexibility at supply-demand coupling.At a higher heat-power ratio,the overall energy efficiency of the proposed system is 1.75% greater,while the optimal capacity of gas turbine is 8.64% lower than that of the reference one.