Thermal calculations and NOx emission analysis of a micro gas turbine system without a recuperator

Abstract

A thermal calculation based on a table of thermal properties of gas was carried out for a micro gas turbine system without a recuperator. The performance parameters of the micro gas turbine system were obtained. The results of the thermal calculations were verified using ASPEN PLUS, and it shows that the thermal calculations fit well with the ASPEN simulation results. Based on this thermal calculation method, the variation of the performance parameters of the micro gas turbine system under different pressure and temperature ratios was analyzed. The results show that there is no optimum pressure ratio within the general design parameters of micro gas turbines, which leads to extreme values of thermal efficiency. The NOx generation in the combustion chamber of the micro gas turbine based on the Zeldovich mechanism was modeled and analyzed by coupling the 1-D thermal calculation model with the NOx emission model. The relationship between NOx generation rate, molar fuel factor, the characteristic pressure, and the characteristic temperature was obtained. The results of the analysis show that, in terms of controlling NOx emissions from a gas turbine, the use of an increased pressure ratio has a significant advantage over an increased temperature ratio to improve the thermal efficiency of the micro gas turbine.