Influence Of Key Parameters On The Thermal Performance Of Heavy-Duty Gas Turbine Combined Cycle

Natural gas-fired generation has attracted much attention as a relatively clean power generation method.As the main technology of natural gas-fired generation,gas turbine combined cycle power generation has the characteristics of starting up and getting off quickly,low emissions and high efficiency.To further improve the efficiency of gas turbine combined cycle and reduce emissions is still an important task of thermodynamic cycle research.Based on the technical parameters of the 9HA.02 gas turbine combined cycle,this paper analyzed the impact of key parameters on the performance of the combined cycle.The uncertainty analysis of the parameters in the model is carried out,and the influence of new technology of gas turbine on the performance of combined cycle is studied.The main research contents and results are as follows:1.By using the quasi-1D turbine cooling model and the concise estimation model of thermodynamic performance for bottom cycle,the present work performed the influence of parameter variation of gas turbine on efficiency and specific work of gas turbine combined cycle(GTCC).The effects of main parameters such as component efficiency,the "cooling-material" technology,combustor exit temperature and pressure ratio on the performance of the system are obtained.The results show that,under Hclass "cooling-material" technology level,the performance improvement of GTCC brought by increasing the combustor exit temperature and pressure ratio is small.Even if when combustor exit temperature is 2000℃,the optimal efficiency of GTCC is only 2 percentage points higher than that of 9HA.02 GTCC.To further increase the efficiency of combined cycle,it is necessary to comprehensively improve the component efficiency and "cooling-material" technology.Results may provide references to enhance the efficiency of GTCC.2.Based on the Monte Carlo method,the uncertainty analysis of the H-class combined cycle system is carried out.The key parameters that have a greater impact on the system performance are identified,and the results are verified.According to the prediction of the development and improvement of key parameters,the possibility of further improvement in the performance of the combined cycle system is discussed.The results show that,compared with the 9HA.02 gas turbine combined cycle,the probability of combined cycle efficiency increasing by 2%is 60%.3.On the basis of the quasi-1D turbine cooling model and triple pressure reheat steam water system established,the effects of fuel preheating,coolant precooling,the combination of fuel preheating and coolant precooling and fuel humidification on the performance of H-class gas turbine combined cycle are investigated.The results indicate that,when fuel preheating is applied,the efficiency of combined cycle is improved.The heat sources in different parts of the bottoming cycle should be selected according to the temperature at which the fuel needs to be heated.After the coolant is precooled,the output of the combined cycle will increase,and the optimal solution for extracting high-pressure feed water in the bottom cycle to precool the coolant is selected.It is found that the combination of fuel preheating and coolant precooling,which is realized by using the extracted working fluid from bottom cycle,can improve the performance of combined cycle compared with the condition of no-preheating and noprecooling.It also better than coolant and fuel heat exchange method.When the fuel is humidified to a saturated state with a lower moisture content,the combined cycle power and efficiency can both increase as the moisture content increases.4.Based on the optimization model of HRSG,the bottom cycle of combined cycle under H-class "cooling-material" level and improved level is optimized by global optimization method,and a higher performance combined cycle is obtained.When combustor exit temperature is 2000℃ and the pressure ratio is 30,the efficiency of combined cycle reaches the highest,which is nearly one percentage point higher than that of combined cycle without optimization of bottom cycle.