中速ディーゼル機関のNOx変動因子

Abstract

This paper describes the influences of fluctuation factors in respect to NOx emissions from medium speed diesel engines.In Part 1, to examine the NOx-concentration correction formula specified in the Technical Code, the authors conducted yearlong research using two types of power-generating medium-speed diesel engines. The purpose of this research was to identify seasonal fluctuation in NOx concentration.In Part 2, the authors performed a combustion test to observe NOx concentration by varying supply air temperature and absolute humidity with the single cylinder engine. Of the three factors, absolute humidity has the greatest impact on NOx. This test proved that, when the engine load is high, the required NOx-concentration correction on absolute humidity was about double that calculated by the IMO Technical Code.This present report takes into account fuel ignitability and other possible factors that may be related to NOx-concentration fluctuation, and conducted additional analysis on the degree of contribution of fuel properties to NOx emissions, based on the yearlong measurement data of cogeneration engines, which was discussed in Part 1.