Theoretical And Experimental Research On Refinery Wastewater Treatment By Cyclonic Flotation Technology

As the trend of poor quality in crude oil increases and the discharge of oily water standards are more and more stringent,there are more difficulty in refinery sewage treatment.Compact flotation units based on the integration of flotation and cyclone technology are widely used in the field of produced water treatment in offshore platform domestic and overseas owing to its high capacity,better performance,low cost and other advantages.However,it has not been used in the field of refinery wastewater treatment so far.Meanwhile,current researches on cyclonic flotation technology are still in the prototype testing stage and the localization of industrialization apparatus has not been achieved,these problems such as characteristics of micro-bubbles,design and optimization of main equipment have not been in-depth studied.Firstly,working principles and the latest applications of representative compact flotation units at home and abroad are described in this thesis.Secondly,two different micro-bubble generators are used for removing oil experiment,it proves that the oil removal efficiency of BIPTMBG-I typed generator is better;micro-bubble diameter produced by three different porosity porous tubes with BIPTMBG-I typed generator are measured online.Results based on BIPTCFU-III-4 experimental prototype field test show that two-stage continuous operation,average value of separation efficiency is 74.1% without chemical preparations;average value of oil removal efficiency is 87.3% with chemical preparations.On this basis,BIPTCFU-III-20 prototype and BIPTMBG-III-20 generator are designed and tested in the field,the test results indicate that when inlet oily water is less than 480mg/L,average value of separation efficiency is 77.54% without chemical preparations in two-stage continuous operation;average value of oil removal efficiency is 90% with chemical preparations.When inlet oily water is more than 1300mg/L,average value of separation efficiency is 79.24% without chemical preparations,average value of oil removal efficiency is 95.9% with chemical preparations.Adaptability to water quality and operational flexibility are good.Finally,it isfirst to use combination of BP neural network and CFD numerical simulation to study structural optimization of BIPTCFU-III-4 experimental prototype,the final optimization of structural parameters compared with BIPTCFU-III-4prototype,its separation efficiency is 10% higher.Research work mentioned above can not only fill the application blank of cyclonic flotation technology in refinery wastewater at home and abroad,but also improve the existing design theory from a certain extent.They also help accelerate the high-efficiency,closed treatment technology of refinery sewage and the localization of compact flotation units.