烧结余热利用中烧结混合料干燥过程实验研究

利用自行设计的实验装置,开展了kg级烧结混合料干燥实验,研究了干燥介质流量和温度对干燥过程的影响.结果表明:干燥过程是由较短的升速段、较长的恒速段及一定的降速段组成,其中恒速段表现为分段性;升速段、恒速段、降速段对应的水的质量分数(指干基水的质量分数,下同)分别为6.5%～7.5%,2%～6.5%和2%以下;升速段约发生在干燥前10 min内,且当水的质量分数为7.0%～7.5%时,干燥速率最大;不同工况下临界水的质量分数不同,其介于1.6%～2.8%之间;干燥介质流量和温度是影响干燥过程的主要因素,在一定范围内,流量越大,温度越高,干燥速率越大,但它们不成线性关系;干燥介质流量与温度均存在适宜范围.

Experimental Study on Drying Process of Mixture Being Sintered Utilizing Waste Heat

An experimental setup was developed to test the drying process of a mixture (in kg) being sintered, with the effects of drying air flowrate and temperature on the drying process investigated. The results revealed that the whole drying process can be divided into three stages according to the drying rate, i. e., the short rate-rising, long constant rate and fixed rate-dropping, among which the long constant rate stage can further be divided into 2～ 3 substages. The water contents corresponding the three stages are 6.5 % ～ 7.5 %, 2 % ～ 6.5 96 and below 2 %, respectively. The rate-rising stage occurs in about the first 10 min of the drying process and the rate comes up to its maximum value when the water content is 7.0 % ～ 7.5 %. The critical water content changes in the range from 1.6 % ～ 2,8 % under different experimental conditions, and the drying air flowrate and temperature are both verified the main influencing factors on drying process. To a certain extent, the higher the air flowrate and temperature, the higher drying rate, but the relationship between air flowrate or temperature and drying rate is nonlinear. Both drying air flowrate and temperature should be set in appropriate range.