Application Of Antifreeze Heat Pipe Heat Exchanger In Fresh Air Heating Of Ciyaogou Coal Mine

Underground ventilation is an important guarantee for the safe production of coal mines.Most coal mines in our country are located in the severe cold areas in the north.The outdoor air temperature is low in winter.The freezing and falling off of the splashing water at the wellhead will cause danger when directly entering the well.Therefore,wellhead antifreeze measures must be taken in winter.The fresh air sent into the well is heated.Wellhead antifreeze energy consumption is relatively high.In view of the current situation of energy shortage and the introduction of national energy conservation,emission reduction and environmental protection policies,coal-fired boilers,electric boilers produce high-temperature steam or water as a heat source for coal mine wellhead antifreeze.High energy consumption and high pollution Traditional methods have been gradually eliminated,reducing primary energy consumption and seeking alternative waste heat resources have become one of the important measures for coal mine energy conservation.In recent years,the use of waste heat resources in mining areas combined with heat pump technology and integrated heat pipe technology to achieve anti-freezing of coal mine wells and heating of ground buildings has been widely promoted.Reducing steel consumption and improving the efficiency of energyusing equipment is another way to alleviate the energy shortage problem.Heat pipes are heat transfer elements with high thermal conductivity.The heat exchanger composed of it has high heat transfer coefficient,large heat transfer,and good isothermality.And has an automatic switch function,which can realize the anti-freezing of the heat exchanger.The use of heat pipe heat exchangers in the fresh air heating of coal mines reduces the volume of equipment,reduces equipment damage,and improves heat utilization efficiency.(1)Relying on the waste heat utilization project of Shanxi Ciyaogou Coal Mine,the research found that the traditional finned tube partition type wellhead heater with water as the heat carrier has the problems of low heat transfer efficiency and easy freezing and cracking of heat exchange tubes.It is proposed to prevent freezing Type heat pipe heat exchanger is used for fresh air heating in coal mines.(2)According to the basic theory of heat pipe technology,design and manufacture of single tube and heat pipe heat exchanger,and conduct heat energy test.Heat pipe heat exchanger is used in the wellhead anti-freezing system of Ciyaogou Coal mine,which solves the problems of low heat transfer efficiency of traditional wellhead heater and freezing crack of heat exchange tube.(3)By measuring the supply and return water temperature,inlet and outlet air temperature,water volume,and air volume data,calculate the heat transfer of the evaporation section and the condensation section,and it is reasonable to determine that the length ratio of the heat pipe evaporation section and the condensation section is about 1:2.(4)The best filling rate of the working fluid is between 30%-35% of the volume of the evaporation section;at the best filling rate,the heat pipe with the working fluid of R22 has a lower temperature than the heat pipe with the working fluid of R134 a and acetone.Starting temperature and working temperature,the evaporation section absorbs less heat so that the heat pipe can start and work normally.(5)After the heat pipe heat exchanger is put into operation,the air temperature,wind speed,air volume of the condensing section,and the inlet and outlet water temperature and water flow rate of the evaporation section are tested.The analysis data shows that the water temperature and water flow rate on the evaporation side are basically stable.When the inlet air temperature is-7.4°C,the heat gain of the fresh air in the condensing section is 474.41 k W;when the inlet air temperature is-19.2°C,the heat gain of the fresh air in the condensing section is 589 k W.The heat gain of the fresh air depends on the inlet air temperature.The lower the inlet air temperature,the greater the heat gain of the fresh air,that is,the greater the heat transfer of the heat exchanger.