NO formation analysis in a dual fuel two stroke engine

Abstract

This article shows basic features of the gas supply system in twostroke dual-fuel engines with a high-pressure gas injection system from MAN B&W. The main methods of using gas as the main fuel for LNG tankers have been considered. Distribution of boil-off gas to ship consumers through the use of high-pressure multistage reciprocating compressors is described. The main differences between gas injection engine systems and conventional electronic engines of the ME-C series are indicated. The article presents the analysis of the mechanisms of nitrogen oxides formation; a calculation method is presented using an integral equation. An extended thermal model for the formation of nitrogen oxides (the Zeldovich mechnism) has been considered, formulas for calculating the reaction rate constants for the Zeldovich mechanism have been developed. According to the equation, when refining the ratio of the nitrogen oxide concentration to its equilibrium value and the reaction rates, an integral equation has been obtained for calculating the amount of nitrogen oxides. The paper shows the results of the multi-zone calculation of nitrogen oxides at various loads of the MAN 6S70 ME-GI engine (25%, 50%, 75%, 100%) in dual-fuel and single-fuel modes. It is shown that the largest emissions are produced at the moment of pilot fuel ignition.