高放废液回转煅烧炉的启动方法

    Starting Method of High Level Liquid Waste Rotary Calciner

    • 摘要: 在两步法冷坩埚玻璃固化工艺中,当高放废液刚开始进料时,回转煅烧炉内温度较高,液体在高温炉管上容易发生莱顿弗罗斯特效应,导致最初一批高放废液不能完全实现前部蒸发、后部煅烧的工艺过程。当高放废液进料量过大时,更有高放废液从炉尾流出的风险,所以需要在进高放废液之前借由水(或稀释的高放废液)带走炉膛内多余的热量使温度降低,这个过程称为回转煅烧炉的启动过程。本工作研究了水、稀释模拟高放废液、模拟高放废液三种启动介质在5、15、30 r/min三种转速下对回转煅烧炉低温启动和高温启动的影响。启动验证试验结果表明:低温启动时,启动效果为水>稀释的模拟高放废液>模拟高放废液,推荐的转速为15 r/min,流速为40 L/h;高温启动时,启动效果为模拟高放废液和蔗糖的混合溶液≈稀释的模拟高放废液>水,推荐的转速为30 r/min,流速为80 L/h。并且通过试验验证了上述两种启动工艺的可行性,试验结果对优化回转煅烧炉工艺,推动两步法冷坩埚玻璃固化技术进入工程化具有一定的指导意义。

       

      Abstract: In the two-step cold crucible induction melting vitrification process, the Leidenfrost effect can lead to the formation of a vapor layer on the furnace tube when high level liquid waste(HLLW) is introduced. This phenomenon occurs due to the high temperature of the rotary calciner, preventing the initial batch of liquid from fully evaporating and calcining. Additionally, excessive feed quantities increase the risk of high level liquid waste exiting the furnace prematurely. To address this, excess heat must be removed by introducing water(or high level liquid waste) before feeding the HLLW, a procedure known as the calciner start-up process. This study investigated the effects of three start-up media: water, diluted HLLW, and simulated HLLW at rotational speeds of 5 r/min, 15 r/min, and 30 r/min on both low- and high-temperature start-up processes. The results of verification test indicate that for low-temperature start-up, water is the most effective medium, followed by diluted HLLW and simulated HLLW. The recommended parameters are a rotational speed of 15 r/min and a flow rate of 40 L/h. For high-temperature start-up, simulated high level liquid waste with sucrose and diluted HLLW have similar effects, both of which are superior to water. The suggested parameters are a rotational speed of 30 r/min and a flow rate of 80 L/h. The feasibility of these start-up processes was confirmed through experimental validation. These findings provide valuable insights for optimizing the rotary calciner process and advancing the engineering application of the two-step cold crucible induction melting vitrification technique.

       

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