dc.description.abstract |
Natural gas combined cycle power generation is one of the current power generation mainstream, but there are still higher fuel costs, nitrogen oxides emission reduction and other issues. The practical aspect of use the air-fuel ratio (AFR) method to derive the combustion flame temperature and that can be calculated as the function of gas turbine inlet temperature and thermal efficiency. In addition, we also compare with power output conversion thermal efficiency method. They can be correlated with the equipment performance and as a diagnostic method.
In this thesis, the application of thermodynamics principle to the first law of thermal balance, the second law entropy increase theorem and natural gas components after combustion of flue gas emissions from excess oxygen are adopted to calculate the air-fuel ratio(AFR) and used to chemical equilibrium reaction derived gas turbine inlet temperature(TIT), combined with the operation example of the gas turbine thermal cycle, to calculate the Brayton cycle efficiency of the gas turbine and to evaluate the performance of the equipment. At the same time, the air-fuel ratio is calculated as a function of the combustion flame temperature, to provide the application of the calculation model and the relationship between nitrogen oxide emissions and AFR adjustment is proposed.
Experimental results showed that 501F type GT AFR(kg) is about 46 and 501G GT is about 42 when the gas turbine thermal efficiency is the optimal. And the promotion of fuel and combustion air temperature on the thermal efficiency and nitrogen oxide emission concentration is very promising, and enhancement of the combustion air temperature function has greater impact than that of the fuel temperature.
The maximum flame temperature of the combustor is calculated by using the AFR as a function of TIT to further evaluate the working capacity of the gas turbine, and it is highly accurate (favorable) to compare with the actual power output efficiency of the gas turbine. Furthermore, TIT can be used as the diagnostic tool for the early monitoring of defective components or assembly of the power plant.
Keywords:Natural gas combined cycle power generation , NOx, Air-fuel ratio (AFR), Gas turbine inlet temperature (TIT), Combustor, Flame temperature | en_US |