Influence of Mine Environmental Factors on the Liquid CO2 Pipeline Transport System with Great Altitude Difference

Abstract

To prevent coal spontaneous combustion and store CO2 in the coal mine, it is necessary to establish a fire-prevention pipeline transport system which continuously injects a large amount of liquid CO2 from the ground to the underground area directly. At present, few studies are focused on the law of liquid CO2 transport with great altitude difference. Moreover, the complex transport environment in the coal mine affects the design and application of the pipeline transport system for ground direct injection of liquid CO2. This study explores the influence of environmental factors at different depths in the coal mine on the liquid CO2 transport. Excessive altitude difference, ambient temperature and airflow velocity may lead to the boiling of liquid CO2 during pipeline transport and a sudden drop in CO2 temperature and pressure, which may cause danger in the pipeline transport system. The critical insulation thickness is determined based on the occurrence of the boiling of CO2. In addition, the influence law of adding an insulating layer of different thicknesses to the CO2 pipeline system is obtained. This study is of great significance to the establishment of a pipeline system that safely transports liquid CO2 from the ground to the underground mine.