Research On The Structure And The Characteristics Of Compound Hydrocyclones

The hydrocyclone has become a type of unique separation facility due to its special separation principle and structural characteristics. The application fields are extending wider and wider. The normal used dynamic and static hydrocyclones have shown many advantages respectively in oilwell produced-fluid pre-separation and oily wastewater treatment. At the same time, some shortcomings have been also exposed. Therefore, it is very necessary for oilfield development to research and produce new-type high performance hydrocyclones.Considering the characteristics of both dynamic and static hydrocyclones, a new type hydrocyclonic separator, compound hydrocyclone, is proposed in this thesis. It keeps dynamic hydrocyclone's high revolving strength and small pressure drop. The separating section adopts fixed structure, which weakens the effect of structural vibration on inside flow field to a great extent.Based on establishing modularized testing rig of compound hydrocyclones, reasonable structural parameters of revolving bar number, bar length, synchro-revolving tube length, and over flow tube size are obtained by means of experimental analysis. Relationships of inlet flowrate with pressure drop and with pressure drop ratio, split ratio with separation efficiency, motor speed with pressure drop and with separation efficiency and so forth are ascertained by experiments.By utilizing Laser Doppler Anemometer the tangential and axial velocity fields of static hydrocyclones and compound hydrocyclones were measured and analyzed. The basic distribution laws of the tangential and axial velocities of compound hydrocyclones are obtained.Based upon the basic principle of RNG K- odel, after modifying K- ε model, the mathematical model of the compound hydrocyclone was constructed. The discreting of transportation equation was realized by applying control volume method and intervein gridding technique. SIMPLE arithmetic was adopted to realize numerical simulation of the compound hydrocyclone's inside flow field. The results were compared with actual measuring data.Referring to oilfield technological process, experimental research of oilfield oily wastewater treatment and oilwell produced-fluid pre-separation was earned out successively. Results show that the compound hydrocyclone is competent for oilfield production.The research work on the structure and the characteristics of compound hydrocyclones in this thesis can provide important reference for reasonable selection of new type hydrocyclone's geometric parameters and operating parameters. It can also provide new thoughts for improving oilfield water treating effect and enhance the technical level of wastewater treatment.