Experimental investigation on the thermal performance of cooling pipes embedded in a graphitization furnace. (15th February 2017) - Shen, Chong
Abstract: A system of embedding pipes in the graphitization furnace to recover heat and accelerate cooling was proposed recently. Numerical study has shown the potential of this approach, but it has not been applied and evaluated in the real environment. Hence in this study, the practical requirements of the pipe-embedded system are discussed, and alternative solutions are proposed and compared. The heat recovery and cooling effect of the modified system is experimentally investigated through a complete heating and cooling process. The influence of fan frequency and external insulation is discussed. The safety of pipes is checked. The results show that: (1) the improved system functions well in the practical condition and the highest temperature of the pipes is 1100 °C and in a safe range; (2) in total 28.2% of the heating energy is recovered and one third of the cooling time is saved, and a high fan frequency will lead to both a high heat recovery rate and high fan energy consumption, but the recovered heat is much higher than the fan power; (3) the top surface takes up 67% of the total heat dissipation and the external insulation can reduce half of the heat dissipation in the heating period. Highlights: Cooling pipes are embedded in the furnace with gas ventilated inside. A practical design of the heat recovery system is proposed and validated. Based on experiments, 28.2% of the heating energy can be recovered. The cooling period is reduced by nearly one third. The influence of flow rate and external insulation is investigated.