煤化工废水零排放的工程运行及结垢离子脱除的分析研究

Study on operation of wastewater zero liquid discharge and scaling ions removing in coal chemical industry

分析了煤化工废水零排放实施的必要性及可行性,以某年产200万t合成氨、350万t尿素项目为例,探讨了废水零排放工程的运行情况,以及结垢离子的脱除技术。介绍了回用水处理和浓盐水处理的工艺流程和运行中存在的问题,运行调试中发现二价离子的去除在煤化工废水零排放中起着至关重要的作用。针对运行中存在的问题采取了改进措施,主要包括蒸发系统连续出盐、离子交换器实时监测确保系统产水二价离子的精度、保证再生液系统的稳定运行,以及对操作人员的严格规范培训。改进后零排放系统的二价离子受到了控制,末端蒸发系统的结垢清洗频率大幅降低,从而大幅度提高了零排放系统运行稳定性。

The necessity and feasibility of wastewater zero liquid discharge in coal chemical industry is analyzed,and taking a certain project of2000kt/a synthesis ammonia and3500kt/a urea as example,the operation of wastewater zero liquid discharge is discussed and the scaling ions removing technology is presented.The process of reuse water treatment and concentrated saltwater treatment is expounded and the problems existed in the operation are analyzed.It is pointed out that removing divalent ions plays key role in the wastewater zero liquid discharge in coal chemical industry.Aiming at the problems,some improvement measures are adopted mainly including continuous discharge of salt from vaporization system,real time monitoring of ion exchanger to ensure the precision of divalent ions in producing water,assuring the stable operation of regenerated liquid system,and standard training of the operation staff.The content of divalent ions in wastewater zero liquid discharge system is controlled after improvement,and the scaling washing frequency of the terminal vaporization system reduce greatly,therefore,the stability of wastewater zero liquid discharge system operation increases significantly.