LU Lin, JI Hangyu, ZHOU Chuanfang, FENG Qing, LIU Xiaoye, QI Huaxin

(Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China)

Abstract: With the development of construction ceramics industry, rock slabs in recent years have been popular with consumers. Compared with ordinary building tiles, the firing requirements of rock plates are more stringent, especially in the slow cooling stage of roller kiln. Therefore, by changing the arrangement of heat exchange tubes, a new type of slow cooling structure is proposed in rock plate roller kiln, where the new structure can be cooled by using hot air. In the new structure, the temperature difference between the upper and lower surfaces of the rock plate can be minimized. Such temperature difference at the highest temperature point is close to 0 ℃, while that in the ordinary structure rock plate reaches 8 ℃. The change in air velocity and temperature in the new type heat exchange tube has almost no influence on the velocity field in the kiln, while the variation range of temperature in homogeneity coefficient in the inner section of the kiln caused by the change of temperature in the tube is less than 1.5%. The comparison between the new slow cooling structure of rock plate roller kiln and the slow cooling structure of ordinary building ceramic roller kiln is conducted and the influence of flow velocity and temperature in the heat exchange tube of the new slow cooling structure on the velocity field and temperature field in the kiln is studied with numerical simulation.

Key words: rock plate roller kiln; heat exchange tube; temperature gradient; uniformity; numerical simulation