Coal Combustion by Wet Oxidation

Coal Combustion by Wet Oxidation
Author:
Publisher:
Total Pages:
Release: 1980
Genre:
ISBN:

The combustion of coal by wet oxidation was studied by the Center for Waste Management Programs, of Michigan Technological University. In wet oxidation a combustible material, such as coal, is reacted with oxygen in the presence of liquid water. The reaction is typically carried out in the range of 204/sup 0/C (400/sup 0/F) to 353/sup 0/C (650/sup 0/F) with sufficient pressure to maintain the water present in the liquid state, and provide the partial pressure of oxygen in the gas phase necessary to carry out the reaction. Experimental studies to explore the key reaction parameters of temperature, time, oxidant, catalyst, coal type, and mesh size were conducted by running batch tests in a one-gallon stirred autoclave. The factors exhibiting the greatest effect on the extent of reaction were temperature and residence time. The effect of temperature was studied from 204/sup 0/C (400/sup 0/F) to 260/sup 0/C (500/sup 0/F) with a residence time from 600 to 3600 seconds. From this data, the reaction activation energy of 2.7 x 10/sup 4/ calories per mole was determined for a high-volatile-A-Bituminous type coal. The reaction rate constant may be determined at any temperature from the activation energy using the Arrhenius equation. Additional data were generated on the effect of mesh size and different coal types. A sample of peat was also tested. Two catalysts were evaluated, and their effects on reaction rate presented in the report. In addition to the high temperature combustion, low temperature desulfurization is discussed. Desulfurization can improve low grade coal to be used in conventional combustion methods. It was found that 90% of the sulfur can be removed from the coal by wet oxidation with the carbon untouched. Further desulfurization studies are indicated.

Spontaneous Combustion of Coal

Spontaneous Combustion of Coal
Author: Xinyang Wang
Publisher: Springer Nature
Total Pages: 240
Release: 2019-11-22
Genre: Science
ISBN: 3030336913

This book aims to understand, analyze and mitigate the harmful impacts of spontaneous coal combustion in underground mines, a thermal phenomenon that triggers fires and explosions threatening the safety of mine workers globally. Based on experimental and theoretical research findings, the book emphasizes three essential questions that are fundamental to understand spontaneous coal combustion: What are the root causes? How to evaluate the causative factors to determine the activity of coal? and How to bring this issue under control in real longwall panel? Readers are introduced to experimental techniques applied to investigate the basic molecular structure of coal and evaluate chemical properties that induce self-heating behavior, theoretical analyses to predict the extrinsic effect on low temperature oxidation of coal in experimental scale and full-size longwall panel, and preventive measures to mitigate this issue using methods for retardant screening, numerical simulations for optimal grouting and nitrogen injections, and case studies analyzing thermal events using mine atmosphere gas monitoring data. The book will be of interest to students and researchers studying mining engineering and chemistry, as well as engineers and practitioners involved in coal mine development and risk assessment.