| The data shows that China’s recyclable industrial waste heat resources are very rich.If it can be fully recycled,it can significantly improve the comprehensive energy utilization efficiency of China’s industrial production and play an important role in energy conservation and emission reduction.At present,the research on the recovery and utilization of high-grade heat sources such as high-temperature exhaust gas(steam)and waste slag in industrial waste heat in China is relatively mature and widely used.However,there are few studies on the recovery and utilization of low-temperature industrial waste heat,especially waste water waste heat,but this part Due to the extensiveness of its industrial waste heat,its total amount is also quite huge,with great potential for energy saving and emission reduction.In terms of industrial waste heat recovery,heat pipe heat exchangers are a more commonly used heat exchange equipment,especially in the recovery of high temperature flue gas waste gas,gas-gas,gas-liquid heat pipe heat exchangers have a large number of practical cases;It mainly has the following advantages:(1)good heat exchange performance,(2)small heat transfer temperature difference,(3)safe and reliable.In this paper,we will study the application of liquid-liquid heat pipe heat exchangers in the field of waste heat recovery of low-temperature industrial wastewater through theoretical analysis,simulation calculation and experimental verification.At present,the heat pipe heat exchanger does not have a relatively mature calculation formula in the field of liquid-liquid heat exchange.Based on the existing theoretical research,referring to the design calculation formula of the gas-liquid heat pipe heat exchanger and the related theory of fluid heat transfer,it is summarized The design calculation formula of the liquid-liquid heat pipe heat exchanger was designed,and the heat pipe heat exchanger used for the recovery of low-temperature waste heat was designed.Using CFD numerical simulation software,the heat exchanger is modeled and numerically simulated,and the heat exchange effect and resistance loss of the heat pipe heat exchanger at different temperatures and different water flows are analyzed and studied.The simulation results show that with the gradual increase of the water flow,the heat exchange effect of the heat exchanger is significantly improved,but with the gradual increase of the flow,the circulation resistance of the heat pipe heat exchanger is also approximately an exponential increase;here On the basis of an energy efficiency analysis,the value of the energy efficiency showed a trend of increasing first and then decreasing with the increase of water flow,reaching the highest value at 20.0 times the water flow(that is,20,000 kg / h).It can be obtained that the heat pipe heat exchanger cannot blindly pursue excessively high water flow rate in practical applications.Under the research conditions of this paper,the recommended flow rate is 0.16 m / s～0.8m / s,and the recommended flow range is 4000 kg / h～20000kg / h.Finally,an experimental platform was built to obtain the actual operating data of the heat exchanger.The data shows that the liquid-liquid heat pipe heat exchanger designed for low-temperature industrial waste heat recovery in this paper can recover up to 18.77 k W in the measurement range,and it can be obtained from simulation and analysis rules.The continuous increase of the heat exchange capacity can be further improved,which is of great significance for practical engineering applications. |
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