A numerical study on combustion behaviours of hydrogen-enriched low calorific value coal gases

摘要

This study focuses on the combustion behaviours of low calorific value coal gases containing additions of hydrogen. The main goal of the present study is to improve combustion performances of low calorific value coal gases by enriching hydrogen. Investigations have been numerically performed by using a CFD code. PDF/Mixture Fraction Model has been used as combustion model. Moreover, k-epsilon realizable turbulence model has been selected as turbulence model because of capturing better results with the experimental results. Before the low calorific value coal gases are consumed by enriching hydrogen, the methane, which is a major component of natural gas, has been burned as the baseline fuel to verify predictions. The predicted temperature profiles of the methane flame are compared with the experimental results and these predictions are in good agreement with the measurements from the literature. Then, the low calorific value coal gases are enriched by hydrogen from the same fuel inlet stream by volume and the hydrogen-enriched low calorific value coal gases have been modelled in the combustor. According to the predictions, combustion characteristics of hydrogen-enriched low calorific value coal gases have been improved considerably as the coal gases are enriched by hydrogen. Although, the NOx levels are slightly increased as the hydrogen is added to coal gases. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.