Review of modern coal drying methods with the evaluation of their efficiency

Abstract

Relevance. The need to analyze the current state of the subject of coal drying in order to identify the most effective methods in terms of time and energy costs, as well as environmental safety and improve the quality of fuel. As practice shows, drying is one of the most important stages in coal preparation for combustion, it helps to increase thermal efficiency, reduce emissions and environmental pollution, increase energy capacity and improve combustion stability. Among the main methods of drying coal, drying with evaporation: A) rotary drying; B) drying in a fluidized bed; C) immersion drying with hot oil; D) drying in a microwave oven, as well as drying without evaporation: A) hydrothermal dehydration; B) mechanical/thermal dehydration; C) solvent extraction, can be distinguished. At the same time, each of these methods is constantly evolving and it is required to evaluate the influence of the dynamics of these changes on the key characteristics of drying. Aim. Review and analysis of modern methods of coal drying, the most efficient in terms of time and energy costs. Object. Wet material – coal, subjected to various drying methods. Methods. Search for works on the stated topic, checking the indication of the main drying parameters: time, energy consumption, etc. Based on the data obtained, a comparison of various drying methods was carried out, and optimal methods were recommended. Results. The authors have considered the modern methods of drying coal and assessed their effectiveness. Rotary drying, hot oil immersion drying, mechanical/thermal dehydration and solvent extraction were found to be the most energy efficient methods for drying coal. The paper considers the features of each drying method.