Geochemical Characteristics of Rare Earth Elements in Sewage Discharge Channels of Tianjin

The geochemical features of rare earth elements (REEs) in the North and South sewage discharge channels of Tianjin were studied. The results show that concentrations of dissolved REEs in water of the sewage discharge channels are very low, while concentrations of Eu and heavy REEs are higher than those in natural rivers. Concentrations of REEs in unfiltered water are high and they mainly resided on suspended matter. Distribution patterns of the dissolved and suspended light REEs vary reversely with the atomic number. Concentrations of REEs in the sediments and suspended matter are lower than those in natural rivers, and concentrations of REEs in the suspended matter are much lower than those in the sediments. Distrib.ution patterns of REEs in sediments and suspended matter were similar with light REE enrichment and positive Eu-anomaly. This distribution pattern is different from those of natural rivers. The differences may cause by the large amount of organic pollutants in sewage.     

一种PLC变频升降故障的分析与解决

炼钢铁水预处理的变频控制系统,含提升电机、提升链条、喷枪小车架及喷枪和喷枪小车等,枪位由一台KUEBLE绝对值编码器反馈,有上下两个极限,基于编码器提供的信号,PLC通过VFD对喷枪的运行速度、位置进行自动控制,驱动链条带动喷枪小车及粉剂管道等按工艺要求完成下降和提升。在成产过程中出现:离开喷吹点升降操作时报故障停机,此时喷枪无法提出,直接影响生产。向DANIELI CORUS外方工程师咨询,认为是变频器自身问题不属于其服务范围,未能给予解决。经过我厂技术人员跟踪、统计,并对变频器、控制回路、外方图纸、程序研读后综合分析,找出了症结并提出解决方案:改进外方原有控制程序,在编码器位置参数反馈至PLC到PLC向变频器发出动作启动信号直至变频器驱动动作开始之间,预设延时并根据实验调整时长,优化变频控制斜坡、抱闸等参数,调试和使用后圆满解决,动作平顺,位置准确。平稳运行至今已1年。     

“望闻问切”点检法在邯钢一炼钢转炉电气设备中的应用

针对邯钢一炼钢120 t转炉设备在实际生产中存在故障率高、故障隐蔽性较强、查找电气设备隐患难度大等问题,对点检炼钢转炉生产设备时使用的“望闻问切”点检法进行了详细阐述。应用实践表明,该法可有效降低故障率,提高生产价值。