Thermodynamic research of coal mining waste gasification processes

Abstract

Purpose. Research aims to study the thermodynamic patterns of coal mining waste gasification process and the formation of a theoretical basis for carbon conversion processes with the production of synthesis gas with a high hydrogen content. Methods. Thermodynamic calculations are based on the main carbon conversion reactions in the temperature range of 500-1100°C and pressures of 1-10 atm. To assess the probability of the flow of processes, the values of Gibbs energy, equilibrium constants and equilibrium conversion degree were determined, which made it possible to predict the composition of the gas phase and determine the optimal gasification conditions. The method of least squares was used to ap-proximate the obtained dependences. Findings. It has been determined that coal mining waste dumps pose a significant source of environmental hazard, since they lead to pollution of soil, water resources and atmospheric air. Traditional methods of utilization focus mainly on localization, but do not provide complete neutralization of harmful components. The conducted thermodynamic calculations confirmed the expediency of using the gasification process, which is effective at temperatures above 860°C. The autothermal nature of this process is achieved through the partial oxidation of carbon to carbon monoxide (CO), which compensates for heat loss. It has been found that increasing pressure reduces the equilibrium degree of carbon conversion. The obtained thermodynamic dependences make it possible to predict the composition of synthesis gas and, subsequently, to assess the prospects for the implementation of technologies for complex recycling of coal mining waste. Originality. For the first time, a comprehensive thermodynamic assessment of coal mining waste gasification reactions has been conducted, and thermodynamic dependences of Gibbs energy change, equilibrium constants, and equilibrium conversion degree have been obtained over a wide range of temperatures and pressures. This made it possible to determine the optimal conditions for the process flow and confirm its technological feasibility at temperatures above 860°C. Practical implications. The results of the research form a theoretical basis for creating effective technologies for complex recycling of coal mining waste to produce synthesis gas, which can serve as a promising energy source, ensuring compliance with modern principles of sustainable development and rational nature management.