Minimum temperatures for sustainable ignition of coal water slurry containing petrochemicals

This paper presents the conditions and characteristics of the sustainable ignition of coal water slurry (CWS) containing petrochemicals in the air flow. This study may be useful to expand the raw material base for the power industry and the effective recycling of low-grade wastes from coal and oil processing. We use an experimental setup to investigate the ignition of slurry droplets with the radius from 0.5 mm to 1.5 mm when heating in the air flow with the temperature of 500-900 K and rate of 0.5-5 m/s. The present paper also studies necessary and sufficient conditions for the ignition of the different slurry compositions. We reveal the minimum ignition temperatures of slurry droplets in air flow. In addition, we show that these temperatures can be significantly less than the temperatures in combustion chambers of power plants (as a rule, higher than 900 K). Furthermore, we determine the times of ignition delay and complete combustion for slurry droplets, as well as the influence of the air flow temperature and rate, droplet sizes, and slurry composition on these times. Research results show that combustion initiation conditions and characteristics of fuel compositions can vary within wide ranges. This effect contributes to using CWS containing petrochemicals in power engineering, chemical, petrochemical, and transportation industries. (C) 2016 Elsevier Ltd. All rights reserved.