燃煤电厂脱硫废水多效蒸发浓缩工艺研究

Research on Multi-effect Evaporation and Concentration Process of Coal-fired Power Plants Desulfurization Wastewater

多效蒸发技术是实现脱硫废水浓缩的一种重要手段,但在工业应用中存在着容易结垢、运行稳定性差等问题。本文首先利用实验室实验装置研究了脱硫废水蒸发浓缩过程中的密度随浓缩比的变化特征,提出了浓缩比-密度预测公式,基于中试平台开展了不同工况条件下脱硫废水多效蒸发浓缩系统的运行特性研究,并将试验结果应用于工程项目中。结果表明:废水中石膏晶种的存在降低了换热器表面结垢风险;提高脱硫废水流速有利于提高脱硫废水溶液与蒸汽之间的换热效率,且可以减少固体悬浮物在管壁侧的沉积。基于晶种法的多效蒸发废水零排放技术可以实现脱硫废水6倍以上的浓缩。

Multi-effect evaporation technology is an important means to achieve concentration of desulfurization wastewater.There are problems such as easy scaling and poor operational stability in industrial applications.This paper first uses a laboratory experimental equipment to study the changing characteristics of density with concentration ratio,the concentration ratio-density prediction formula is proposed.Based on the pilot platform,a study on the operational characteristics of the desulfurization wastewater in a multi-effect evaporation system under different working conditions was carried out.This paper applied the experimental results to engineering projects.The results show that the presence of gypsum crystal seed in wastewater reducing the risk of scaling on the heat exchanger surface;In addition,increasing the flow rate of desulfurization wastewater will help improve the heat exchange efficiency between the desulfurization wastewater solution and steam.Moreover,it reduces the deposition of solid suspended matter on the side of the pipe wall.The zero discharge technology of multi effect evaporation based on crystal seed method can achieve more than 6 times concentration of desulfurization wastewater.