Characteristics and conditions of ignition of wet coal particles during high-temperature heating

Abstract

Relevance. Today, increasing attention of the world community is being paid to the problems of ecology and global warming. Objective prerequisites are emerging for more active introduction of renewable energy sources and energy carriers into thermal and electrical energy production cycle. But non-traditional energy sources, such as wind generators and solar panels, have a number of significant disadvantages, the main one of which is that the stability of renewable energy sources depends significantly on weather conditions and time of day. For this reason, the governments of many countries are already discussing new programs for the development of the economy energy sector based on the large-scale construction of nuclear and thermal power plants. This global problem can be solved by switching to wider use of coal as an energy source. Coal thermal power plants provide stable production of thermal and electrical energy, unlike renewable energy sources. But coal is a “dirty” fuel – when it is burned, it produces significant amounts of anthropogenic emissions, such as carbon dioxide, as well as sulfur and nitrogen oxides. Aim. Experimental studies of the conditions and characteristics of ignition (thermal preparation times) of humidified coal of several fairly common and widely used brands and the amount of nitrogen oxide in their combustion products. Object. Humidified coal of four grades (lean, long-flame, anthracite and brown). Method. To establish the main characteristics and conditions of coal fuel ignition and combustion under high-temperature heating conditions, a special experimental stand was used. Results. The results of experimental studies are presented to substantiate the possibility of using four grades of humidified coal as the main fuel in thermal power engineering. The authors have established nitrogen oxide sequestration in the combustion products of the latter in a small vicinity of a humidified coal particle in comparison with dry coal under high temperature conditions. The experimental studies established as well an insignificant (increase of no more than 11%) influence of additional humidity on the thermal preparation times of single coal particles for the four studied grades of coal.