种分母液蒸发过程中的结垢与防垢研究

【作者】 陈科云；

【导师】 彭志宏；

【作者基本信息】 中南大学 ， 有色金属冶金， 2007， 硕士

【摘要】 在种分母液蒸发过程中，受平衡浓度的影响，碳酸钠等杂质容易在加热器壁上生成结垢，从而严重影响传热和物料流动，甚至阻塞管道，影响生产的正常进行。研究种分母液蒸发过程中结垢的形成规律以及防垢添加剂对减缓结垢的影响，寻找适宜的防垢措施，对氧化铝工业具有十分重要的实际应用价值。论文在对国内外氧化铝生产系统结垢现状和研究动态做了全面了解的基础上，采用对比实验法，研究了种分母液蒸发过程中加热面结垢的形成规律以及防垢添加剂对减缓蒸发过程加热面结垢的影响，结果表明添加GR-4、GR-5等阻垢剂效果明显，可降低结垢量60％～70％，有效减缓加热面结垢的形成速度，并且可以抑制溶液中硅的析出。同时，添加阻垢剂GR-4、GR-5等可使加热面结垢松散，易于清洗。实验确定了阻垢剂GR-4的添加量和添加工艺，研究结果为阻垢剂的工业应用提供了详细准确的工艺参数和理论指导。对种分母液蒸发过程中添加阻垢剂的阻垢机理进行了研究和讨论，结果表明：GR-4阻垢剂能大幅度降低蒸发溶液的表面张力，产生凝聚-分散作用，起到阻垢效果。根据实验室研究结果，某氧化铝厂蒸发生产上应用GR-4阻垢剂，生产运行情况表明：添加GR-4阻垢剂可有效减缓蒸发器的结垢速率，延长设备运行时间和清理周期，有利于提高蒸发效率和降低生产成本。更多还原

【Abstract】 Impurities such as Na₂CO₃ etc easily precipitate to result in the formation of scale on the wall of heater during the evaporation process of spent liquor from seeded precipitation process, which badly influences the heat diffusion and material flow of this process, even block pipe. This is harmful to the production process. Therefore, investigation on the formation law of scale in the evaporation process of spent liquor from seeded precipitation process, study on the influence of anti-scale addictives on the retarding scaling and adoption of proper anti-scale measure are to regard as have a great applying prospect for alumina industry.The formation law of scale on the heating surface and the effect of various anti-scale addictives on the retarding scaling of heating surface during the evaporation process of spent liquor were studied in this paper. Results indicate that addictive type GR-4 and GR-5 etc can effectively retard the formation rate of scaling on the heating surface, restrain SiO₂ from precipitation and decrease the scale yield by 60～70％. Meanwhile, scale occurred on the heating surface can be easily cleaned because it becomes unconsolidated after adding addictive type GR-4, GR-5 etc in the evaporation process. The addition content and addition technology of anti-scale addictive type GR-4 are also determined through experimentation. Results of research on anti-scale addictive type GR-4 can provide a favorable reference for industrial application of scale inhibitor.Subsequently, the anti-scale mechanism of addictive during the evaporation process of spent liquor was investigated and discussed. Results show that scale inhibitor type GR-4 can greatly reduce the interfacial force of evaporating liquor and has flocculation and dispersion effect on the system, which contributes to anti-scale action.Industrial experimentation was performed in some alumina refinery of CHALCO according to the laboratory results. The result demonstrates that scale inhibitor type GR-4 can effectively retard the formation rate of scaling on the evaporator, prolong the run time of equipment and cleaning period. It is propitious to improve the efficiency of evaporation and decrease the production cost.更多还原