Experimental feasibility study on the application of high-temperature heat pipes in the cooling process of graphitization furnaces

Lithium-ion batteries, renowned for their high energy density, long cycle life, and environmental friendliness, have been widely applied. Graphite materials are the mainstream anode materials for these batteries. However, the production of graphite materials involves a prolonged cooling process, which significantly limits production efficiency. High-temperature heat pipes (HTHPs), passive thermal management devices capable of highly efficient and reliable long-distance heat transfer, provide an innovative solution. Building on the advantages of HTHPs, this study proposes a high-temperature heat pipe-graphitization furnace cooling technology (HPGFC) to shorten the graphitization process cycle, achieve thermal energy recovery, and enhance production efficiency. In this study, a potassium HTHP was fabricated, and its heat transfer performance was evaluated experimentally. A prototype system based on the HPGFC was developed. Parameters such as the heat pipe wall temperature and the temperature of the graphite coke layer were measured to verify the feasibility of the proposed technology. Experimental results indicated that the total heat transfer rate of the experimental potassium HTHP reached 5009.8 W, with an equivalent thermal resistance of 0.0298 K W⁻¹, maintaining high heat transfer capacity and excellent temperature uniformity. When inserted into graphite, the HTHP exhibited rapid startup and cooling operation, with a maximum heat transfer distance of 1450 mm. The cooling power increased progressively during the HTHP startup process, reaching a maximum of 1.47 kW at its maximum operating distance, and subsequently decreased. The cooling time with the HTHP was reduced by 178 min compared to the natural cooling method, representing a 33.96 % reduction. The maximum cooling rate of the graphite furnace under HTHP cooling reached 16.93 °C/min, which is 6.32 times that of natural cooling (2.68 °C/min). The average cooling rate under HTHP cooling was 2.13 °C/min, 2.7 times higher than that of natural cooling (0.79 °C/min). In conclusion, this study successfully developed a prototype system for the HPGFC and conducted experimental investigations, thereby verifying the feasibility of the proposed technology.