Ignition Studies on High-Vitrinite and High-Inertinite Coals Using TGA/DSC, DTIF, EFR, and 20 L Dust Explosive Chamber

Wiesław Rybak,Wojciech Moroń,Janusz Wach

doi:10.3390/en14123601

Wiesław Rybak, Wojciech Moroń + Show 1 more

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https://doi.org/10.3390/en14123601

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Abstract

The aim of this work was to study the ignition behaviour of eight coals of different coal ranks, petrographic compositions, and places of origin. The research allows us to gain deeper insight into the ignition mechanism and the relationship between certain properties of coals and their behaviour during ignition. The methodology utilised standard fuel ASTM data, petrographic analysis, pyrolysis and oxidation reactivity, and ignition characteristics generated through lab-scale tests using various ignition measurement methods. The results show that, in the dust explosion, a homogeneous ignition of coal dust took place. The ignition potential was the highest for coals with a high content of liptinites and a low content of inertinites. The ranking of coals in terms of ignition potential under these conditions can be determined on the basis of the measurements of the devolatilization rate. During the combustion of coal dust in TGA/DSC, a dust cloud, and a pulverised fuel stream, the ignition of particles was performed according to a heterogeneous mechanism. The study showed that the reflectance index may be the most reliable method of predicting and comparing ignition temperatures of both vitrinite-rich and inertinite-rich coals. Due to the lack of regularity in the ignition temperatures of some coals, depending on the proportion of inertinites, the petrographic composition of coal cannot be used to predict ignition temperatures during the combustion of coal dust. The ranking of the coals according to their ignition potential can be determined using TGA/DSC.

Highlights

The methodology utilises standard fuel ASTM data, petrographic analysis, and ignition characteristics generated through lab-scale tests using various ignition measurement methods
This work is concerned with determining the parameters and mechanism of the ignition of coal particles with different ranks and different petrographic compositions under conditions where particle interactions take place
Temperature-programmed pyrolysis/combustion Thermogravimetry and differential scanning calorimetry (TGA/differential scanning calorimetry (DSC)), a drop-tube furnace, a laminar entrained-flow reactor, and 20 L explosion chamber operating at high coal-feed rates were used in order to promote interactive effects between the particles

Summary

Introduction

The ignition of coal particles is an important preliminary step in determining fire and explosion hazards in the fuel combustion process. More research, and the development of research procedures, would allow us to predict the behaviour of a given fuel with regard to its ignition efficiency in pulverised fuel combustion (p.f.) and to determine fire and explosion hazards in industrial dust installations. Many fundamental research studies have been conducted regarding solid fuel ignition [1,2,3,4,5] These processes require a deep knowledge of the basic relationships between the physicochemical properties of fuel, its chemical composition, and the ignition parameters. The developed relationships seem to be useful to some extent but usually only if a limited range of coals of one geological origin is used.

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