Case studies investigating single coal particle ignition and combustion

Studies focused on single fuel particles are designed to provide direct and unbiased information regarding the combustion process. The resulting data is primarily used to create and/or validate mathematical theories and models of the combustion process. The use of a single coal particle as a research object was first initiated over 40 years ago and nowadays is still one of the most important stages in a number of fundamental coal research techniques. Such experiments are especially important in the context of modern concepts that are now under development for new, sustainable and environmentally neutral coal processing technologies. Article summarizes a broad spectrum of research methodologies, which were created in the recent history of single coal particle studies and motivated by the need to develop knowledge for new, clean coal technologies. The purpose of the experiments presented herein was to find the most comprehensive examination of the processes, where coal particles undergo changes at high temperatures. This objective in the case of coal combustion technology generally boils down to the characterization of particle ignition phenomenon and sub-stages of particle combustion. However, recent data presented by different research groups is still not always in agreement even when describing the same investigated issue. These differences often result from the shortcomings of the study methodology itself, which our article also attempts to highlight and analyze.