Filter For Solid-liquid Separation Efficiency Of Ship Ballast Water Experimental Research

At present,in order to control the invasion of foreign organisms caused by ship ballast water discharge,the ship ballast water convention was officially in force in early 2019 and many countries including China must install ship ballast water treatment systems to meet the requirements of the Convention.Ship ballast water discharge standards.In order to explore the green and efficient ballast water solid-liquid separation method,this paper carried out the structural design and optimization analysis of the filter through experiments and simulation analysis,and obtained the filter efficiency of the filter to the algae and other organisms in the convention emission standard.And the scope of application,the specific research results are as follows:Complete the design,production and commissioning of the filter.In order to effectively separate algae and other organisms larger than 50?m in ship's ballast water,this paper uses Fluent software to optimize the structural parameters and operating conditions of the filter,and investigates the parameters such as filtration accuracy,influent flow and installation mode.The influence of the internal flow field gives the optimal working condition for its stable and efficient operation.For university separation of substances larger than 50 ?m,the filter filtration precision is selected to be 40 ?m;The installation method of the filter should be vertical installation.If the installation is horizontal,the outlet should be set below;The casing has a diameter of 80 mm and a height of 250 mm;the outer diameter of the filter element is 60 mm and the height is 240 mm;The filter material is made of stainless steel 316L,and the number of openings in the filter support layer is 150.Combined with Darcy's law,Poiseuille equation and KOZENY-CARMAN equation and the relationship between porosity and permeability,the total pressure difference of the filter is calculated to be 0.01827 MPa,which is in line with the empirical design criteria.The solid-liquid separation efficiency of the filter on the ship's ballast water was obtained through experimental research.In the experiment,the algae algae powder was used to simulate the material of the ship's ballast water greater than 50?m.By changing the influent flow rate,concentration,salinity and other conditions,the solid-liquid separation efficiency of different kinds of filter elements was investigated,and the filter was analyzed while improving the treatment efficiency.The cause of the blockage.The test results show that the influent conditions have no significant effect on the solid-liquid separation efficiency of the filter.The removal rate of algae powder in the ballast water by the flat filter is 88.669%-92.299%,and the removal of the pleated filter is adopted.The rate is 87.543%?90.890%;the pressure change caused by the pleated filter element is smaller than the pressure change caused by the flat filter element.The pressure difference is significantly affected by the influent flow rate and the influent concentration,and is not significantly affected by the salinity.The flow rate should not exceed 12.5L/min,and the influent concentration should not exceed 6mg/L.Use response surface analysis to obtain a significant impact factor for filter screen blockage changes.By analyzing the influence factors of the blocking pressure difference,it is found that the influence of the influent flow rate and the running time on the pressure difference between the two ends of the filter is the strongest,followed by the influent concentration and the weakest salinity.Combined with the actual treatment of the ship's ballast water,the optimal operating conditions of the filter are determined:the upper limit of the influent flow rate is 12.5 L/min,the influent concentration is controlled below 6 mg/L,the running time is not more than 65s,and the removal rate is stable between 87%-92%.The research results in this paper can provide a theoretical basis for the filtration treatment technology of ship ballast water to meet the green and efficient processing requirements of ballast water discharge.