Modeling of a Wellhead Heating Methodology With Heat Pipes in Coal Mines

Many coal mines are located at the middle and high latitudes. In winter, coal mining facilities may be operated under the freezing conditions. Burning coal for hot water is usually used to heat up the facilities, which is not environmentally friendly and energy efficient. Currently, the ground source heat pumps and other new technologies have been applied for heating in coal mines and have achieved some success. However, the working characteristics and costs of these technologies are not suitable for the antifreeze at the wellhead. Heat pipe technology has the following advantages: automatic operation with the change of atmosphere temperature (AMT) and low cost of construction and maintenance, which can overcome the drawbacks of the aforementioned technologies. In this article, a heating system based on heat pipe technology has been designed and modeled. The system extracts heat from the shallow normal temperature zone (NTZ) to automatically heat the coal wellhead in winter. For the heating system, the effects of AMT, the temperature of NTZ, the frozen zone thickness (FZT), the thermal conductivity, and the heat pipe quantity (HPQ) on the heating performance have been modeled and investigated using comsol multiphysics. The modeling results have been analyzed and discussed. The modeling data showed that the system based on heat pipes could meet the antifreeze requirements for the designed system during the winter period. The wellhead heating system proposed in this article may achieve the purpose of replacing fossil energy with shallow geothermal energy.