Evaporation Process And Equipment Design Of 36,000 T/a Sodium Chloride And Ammonium Chloride From Wastewater

As the rapid development of sodium bicarbonate industry in China,a large amount of waste liquid containing lots of sodium chloride and ammonium chloride is discharged,which not only lead to the eutrophication of water bodies but also serious environmental pollution.Therefore,it is significant to explore a scientific and reasonable process to utilize the waste liquid containing sodium chloride and ammonium chloride.In this study the evaporation method was adopted to treat the waste liquid containing sodium chloride and ammonium chloride.The evaporation process was studied through basic experiments,and the final operating process was determined.The waste liquid was evaporated at 0.04 MPa(absolute pressure)to get the largest amount of sodium chloride firstly,and then the filtrate was further concentrated to the ammonium chloride saturated.When the liquid temperature was cooled down to 30?,the ammonium chloride crystals began to precipitate.The ammonium chloride mother solution was cycled 4 times to treat.The Aspen simulation software was used to determine the waste liquid treatment process and the two-effect evaporation process was adopted.The Material and energy balance for the total process flow were conducted,and then the type-choosing and design of the equipment was carried out.The related equipment such as settling tank,clear liquid storage tanks,mother liquid tank,heater and separation chamber of two-effect evaporation was designed.At the same time the control scheme of typical equipment was designed,the P&ID flowsheet was drawn,and the workshop equipment layout design was also completed.Comparing with other waste liquid treatment processes,the two-effect evaporation process can make full use of the waste heat of the secondary gas and condensate water,which can reduce the production costs.The process can recover the sodium chloride and ammonium chloride from the waste liquid,and the purity of the product reached over 95%.This study can provide meaningful reference for the design of industrial sewage treatment in the same chemical area.