Study On Flocculation-magnetic Separation Technology Deeply Treatment Of Refinery Wastewater With Salts Content

With the rapid economic development of petroleum and its products have become an important necessity of human, is widely used in various fields of national economy and human daily life. In the petroleum refining process, for avoiding the effects on their equipments corrosion, catalyst poisoning of the follow-up of processing operations and the quality of oil , electric desalting of crude oil must be first. With the processes of oil refining produce salinity wastewater. Presently, technology of the old three processes are used to the treatment of refinery wastewater with salts content. After treatment, the CODcr of the effluent is still 100mg / L or so. State and local governments of the refining industry for more stringent emission standard, now many refineries can not meet the standard of the CODcr less than 60 mg/L that need to be addressed.Flocculation - magnetic separation technology is studied. The results of flocculant screening and selection of experimental conditions show that the PAM associated with ferric chloride has more better effect than aluminum chloride, PAC and other flocculants. Optimal treatment conditions are concluded that the dosage of FeCl3 ? 6H2O is 250 mg/L, the dosage of PAM is 2 mg/L, Magnetite Powder dosage of 2% (w%) of wastewater volume, temperature is 25°C, deposition time of 3min, pH is 8. Under these conditions, the CODcr of the tested wastewater can be from 120 mg/L down to 48.9 mg/L. The studying results of Mechanism of Magnetite Powder demonstrate that the addition of Magnetite Powder enhanced coagulation in the side of the electrical double layer compression, adsorption and bridging etc. Sedimentation rate is 120cm/min that is 5.3 times traditional coagulation. To achieve flocculation-magnetic separation technology industrialization, Against an oil refinery, the Pilot study of 10t/h carries out using the compound flocculations of FeCl3 and PAM. The results show that the dosage of FeCl3 is 250 mg/L, the CODcr of the effluent down to 52 mg/L, the recovery of magnetite powder up to 99.9%. Using this technology pharmaceutical cost is about 0.81 Yuan/ton. Summing up all results conclude that it is technology and economically viable by using flocculation- magnetic separation technology for treating refinery wastewater with salts content.