• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>International Chemical Recovery Conference v.1; 20040606-20040610; Charleston,SC; US >Manipulation of Crystallization to Resolve Severe Concentrator Scaling
【24h】

Manipulation of Crystallization to Resolve Severe Concentrator Scaling

机译：处理结晶以解决严重的浓缩器结垢

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Three of four bodies of a new falling film concentrator have suffered severe capacity loss from soluble scale since start up. Recovery boiler ash is added to the black liquor at the inlet to the 1A effect, and although this effect attains the highest solids content, it is the only concentrator body that does not significantly scale. The practical requirement to have one of the other three concentrator bodies on continuous wash has forced the second effect to operate above 50% solids which has caused it to rapidly foul. Analysis of black liquor samples revealed that the concentrator feed had a Na_2CO_3/Na_2SO_4 weight ratio exceeding 3.7. Recent advances in our understanding of crystallization during black liquor evaporation suggest that the first crystals being formed at this composition are dicarbonate (2Na_2CO_4·Na_2SO_4). High levels of soluble calcium in the black liquor, 300-400 ppm, about 90% of total calcium, are expected to delay dicarbonate nucleation and allow very high supersaturation to develop. The combination of these two conditions suggests that massive nucleation of dicarbonate is responsible for rapid scaling. After the boiler ash is mixed with the black liquor, the crystals produced are expected to be burkeite (Na_2CO_3·2Na_2SO_4), which has less tendency to form tube surface deposits. Causes for the high carbonate-to-sulfate ratio have been identified and several recommendations are under evaluation for modifying chemical make-up strategy to manipulate liquor composition within the concentrator and for recirculation of appropriate seed crystals to relieve supersaturation in the problem effects.
机译：自启动以来，新的降膜浓缩器的四个主​​体中的三个因可溶垢而遭受了严重的容量损失。回收锅炉的灰分在入口处以1A的作用添加到黑液中，尽管这种作用获得了最高的固体含量，但它是唯一没有明显结垢的浓缩器。在连续洗涤中使其他三个浓缩器主体之一的实际要求迫使第二种作用在高于50％的固体含量下运行，这使其迅速结垢。对黑液样品的分析表明，浓缩器进料的Na_2CO_3 / Na_2SO_4重量比超过3.7。我们对黑液蒸发过程中结晶的理解的最新进展表明，在该组成下形成的第一个晶体是碳酸氢盐（2Na_2CO_4·Na_2SO_4）。黑液中的可溶性钙含量高，为300-400 ppm，约占总钙含量的90％，预计将延迟碳酸氢盐的成核作用并产生非常高的过饱和度。这两个条件的组合表明，碳酸氢盐的大量成核是快速结垢的原因。在将锅炉灰分与黑液混合后，预期产生的晶体为榴辉石（Na_2CO_3·2Na_2SO_4），其形成管表面沉积物的趋势较小。已经确定了碳酸盐与硫酸盐之比高的原因，并且正在评估一些建议，以修改化学组成策略，以控制浓缩器中的液体组成，以及再循环适当的晶种以缓解问题影响中的过饱和。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号