Research On Technological Parameters Of Ammonia Distillation And Cyanide Reduction Technology

Based on the fact that the concentration of total cyanide in the effluent of biochemical treatment is too high to meet the regulatory requirements, the paper focuses on reducing the influent concentration of total cyanide coming from ammonia distillation section. It started with analyzing major ingredients in remain ammonia wastewater, then appropriately adjusted the process parameters, with distillation rate of ammonia nitrogen unchanged, aiming to decline the amount of cyanide in the wastewater discharged from ammonia still.Prior to adjustments on ammonia still, the analogue was made on ammonia stripping system by means of chemical engineering analogue software, which has offered a basis for technical modification. Aspen Plus is a well-known chemical process simulation software, widely used in various fields of chemical industry, provided the flow chart of ammonia distillation process in the paper and gave a series of simulation results close to the production practice.The final results after debugging and verification are as below:As the bottom temperature is set to109℃, bottom pressure31.4kPa, the general cyanide is less than10mg/L, accompanying with the distillation rate is up to97%at the operating conditions of16t/h for remain ammonia wastewater inflow,0.08m3/h for alkali with a6%concentration,2900Kg/h for steam inflow. In the subsequent sections, the purity of sodium thiocyanate can be ensured; the total cyanide discharged from biochemical treatment section remarkably decreased within the range of0.1-0.2mg/L.