Research On Heat Exchange Of Inert Gas Rich In Vapour Generator For Long Distance Transport

Technology for defending from or putting out a fire applying inert gases is an effective means for guarding the safe production of a coal mine. Long-distance inert gas producer,which is mainly used for inertizing the closed firing site or for preventing from the self-ignition of the coal,is the driving machine to produce and transport inert gases.The development of long-distance inert gas producer coincides with the orientation of defending-from-or-putting-out-fire technology based on inertization theory.By comprehensively analyzing the defects of ordinary equipment and the in situ application request,it makes long-distance transportation of the inert gas reality,so that it can be prepared as the daily equipment in the mine for controlling of the fire while fire damp explosion ocurred. Therefore it is in safety and economy concern worth while spreading.This study aims at the reduction of temperature and humidity of the high temperature inert gas rich of vapour,so as to get clean dry inert gases. For economic reason,it is requested that the structure of the original inert producer should not be changed.Therefore,a new small,convenient for installation heat exchanger module has to be developed with its dimension limited to the original one.Based on classic heat transmission theory and engineering thermal dynamics,a new method for direct calculation of the inert gas thermal property parameters according to the components of the gas is proposed.It is applicable for the thermal property calculation of the inert gas between 0～1200℃,includingρ,C_p,μandλ.The calculated results satisfy well with those looked-up from traditional tables composed of tested values. Therefore it is a good substitution for the traditional looking-up-table method.For inert mixed gases with different components,the proposed formula can be applied with a little alteration as long as the ingredient of each component is given.Since thermal property parameter calaculation of the fluid is the important part for data processing,the proposed method is a useful tool for heat transmission calculation. The inert gas rich of vapour transmits heat through convection and condensation,but it is neither the same as condensation of pure vapour, nor the same as condensation of vapour containing a little non-condensable gases,as well as nor the same as condensation of cold air.The percentage of vapour in inert gas is usually 10%～25%,while the percentage of non-condensable gas is up to 80%～90%.As for the heat transmission of inert gas in the long-distance inert gas producer,which is rich of vapour, the process includes apparent heat exchange through convection between the inert gas and the transmission face,the potential heat exchange through condensation of vapour,and radiation heat transmission.Based on the scientific analysis and precise calculation of the above heat transmission process,the heat transmission module is optimized.Hence the facility for reduction the temperature and vapour is smallized.This study resolves a key problem for the smallization and application of long-distance inert gas producer,i.e.,the smallization of reduction facility for high temperature inert gases rich of vapour,which concides it to the request for putting out fire equipment in the coal mine - it should be high effective,responding quickly,and convenient for movement.