Numerical Simulation of NOx Pollutant Formation in a Natural Gas Fired Power Generation Boiler, by Using Burner’s Parameters

Abstract

The major source of energy is fossil fuels, known as hydrocarbon containing C and H as the main elements. The heat generated from combustion of these fuels is used in power generation cycles to generate electricity. Main products of a hydrocarbon combustion reaction are water and carbon dioxide, but due to some reasons such as excessive temperature and inappropriate air-fuel mixing, always some pollutants are formed. One of the major concerns of recent years are NOx pollutants, which is mostly generated in the high temperature combustions. According to the geographical and economic issues, most countries are using coal as fuel and many researches have been conducted about pollutant formation and temperature distribution in coal fired boilers (H. Y. Park, et al,. J. R. Fan, et al, and many others), but in Middle Eastern countries, the dominant fuel for the power generation cycles is natural gas. In this paper, pollutant formation and temperature distribution is numerically studied in a power generation boiler using natural gas as fuel. NOx formation mechanisms are introduced and discussed about the main source of NOx pollutants in this boiler. The natural gas burners are appropriate for non-premixed flame, so the goal of this study is to achieve the desired temperature distribution and minimize NOx pollutants through the variation of inlet angle of fuel and air in the burner. A case study is presented for boiler with 156MW power, equipped with natural gas burners. Numerical simulation is applied for the mentioned system and optimization consideration on pollutant is discussed.