Change of coal’s gas content during transportation to the temporary storage

Abstract

Purpose. Definition of correlation between residual gas content in coal stored in closed temporary storages and coal’s natural gas content, which depends on the weather, train’s transportation time and the amount of air ventilating closed storage needed to maintain methane concentration below threshold limit value. Methods. Analysis of the transportation process from excavation site to the temporary storages, which takes into account transportation duration, carriages type and atmospheric temperature; experimental determination of effective diffusion coefficient for methane in coal fragments; theoretical research of thermal pattern dynamic for coal mass in train carriages; computational analysis of coal’s gas content dynamic during transportation and correlation between residual coal’s gas content and required airflow rate for temporary storage ventilation. Findings. This paper represents the results of research of change of coal’s gas content during excavation, transportation to the surface and further transportation to temporary storages by train by evaluating influence of physical and chemical properties of coal, effective diffusion coefficient in particular, and mean atmospheric temperature. According to procured data, value of effective diffusion coefficient, which depends on coal transportation time and its mean particle diameter, increases with the rise of mean coal mass temperature. Calculation of mean coal mass temperature per unit of volume during transportation is based on approximate method of Bubnov – Galerkin. Residual coal’s gas content after transportation is calculated as difference between value of coal’s gas content after loading into carriages and coal’s gas content after delivery to temporary storages. Correlation between residual coal’s gas content and required airflow rate for temporary storage ventilation has been established. Application field of research. The results of the study can be used to ensure methane safety during temporary storage of coal raw materials in closed warehouses.

Keywords

• bituminous coal
• bituminous coal transportation
• coal’s seam gas content
• residual gas content
• methane
• threshold limit concentration
• coal storage
• temporary coal storage