Research On Separation Mechanism & Properties Of Compound Hydrocyclone Utlized On Oilfield Wastewater Treatment

The primary oilfields have been attaining the high water-containing exploitation period nowadays, and the manner of the oil driven has transferred from water to polymer or ternary compound matter. The application of the technology has enhanced the oil production ratio going with some difficulties, such as the produced liquid treatment. New and high efficiency separation equipment and treatment technique must be invented to reduce the occupying space and the construction investment, to ameliorate the technique of oil and gas gathering and transportation. The technology of hydrocyclone separation is satisfied the requirement. The static hydrocyclone succeeds applying on the aspect of oil-water pre-separation and wastewater treatment for the water driven production. But at the aspect of the polymer or ternary compound matter to drive the oil, static hydrocyclone can not be satisfied for. Though the dynamic hydrocyclone has the virtue of high compulsive vortex field, its vibration of outer bed can not easy to eliminate, and this badly affects the hydrocyclone's separation efficiency to improve.Daqing Petroleum Institute has been studying static and dynamic hydrocyclone for about fifteen years, and has grasped their properties. In order to search a new structure to overcome the defects of the dynamic and the static hydrocyclone, it is invented a new equipment named compound hydrocyclone.Compound hydrocyclone thirsts for separating the oil from high viscous liquid mixture, oilfield wastewater, by its special structure, which compounds the virtue of dynamic hydrocyclone's high compulsive vortex field and its body having no vibration to eliminate the factors leading to decreasing the separation efficiency.In order to let compound hydrocyclone go out test laboratory fast, it must be deeply grasped the clone's separation mechanism and separation properties. The research of compound hydrocyclone separation mechanism indicates the separation field studying. The separation field of the compound hydrocyclone is composed of pressure field and velocity field. In the process of the pressure field, the vortex area is divided into two parts by the biggest tangential velocity enveloping surface, semi-free vortex area and compulsive vortex area. The pressure and the pressure drop are analyzed respectively at the two areas utilizing the movement equation and the pressure gradient equation. Under the compound hydrocyclone boundary condition and the integral constant confirmed, the two areas pressure analytic equations and the pressure drop equations are all determined. To the velocity field studying, the compound hydrocyclone's tangential velocity, radial velocity and axial velocity are all gave expression equations in the cylindrical coordinate.For determining the compound hydrocyclone monomer production ability, the production equation is educed by the pressure drop equations and former research result curve fitting which the relationship of the flow rate connected with the diameter of rotational crib, angular velocity of rotational crib. The equation of compound hydrocyclone production indicates that the monomer production is not at an stable value in its working process, and it is connected with some parameters, such as the rotational crib diameter, pressure drop, diameter of overflow nozzle and the main diameter of the monomer which is also called static monomer. All the working can offer the basis to adjust the compound hydrocyclone operating parameters in the process of its utilizing.The rotational crib is the key part in the compound hydrocyclone structure. On one hand, the rotational field to separating the mixture fluid is formed by the crib, and on the other hand, a good crib parameter can let us gain high efficiency in the separating process. The optimization of the compound hydrocyclone actually becomes to the rotational crib parameter optimization. The former research indicates that the helical crib body is evidently better than the straight one. So the optimization becomes to optimize theangle of the helical crib. Owing to the difficulty of determining the aim equations and existing good emulation soft ware which can give us high reliability, the optimization designing is adopt dispersing parameters method to overcome the problems. By the FLUENT soft ware emulation, the helical angle is determined.The energy losing of the compound hydrocyclone is composed of local pressure drop, viscous losing, vortex kinetic energy losing, air cylinder losing, and outlet energy losing. All the manner of the energy losing are analyzed respectively from their forming reasons and determining methods.At the same time, the rated sample equipment whose rated flow rate is at 4.5m3/h is tested in the laboratory and at the oilfield,and the separation ability is grasped. The sample optimum operating parameters are determined by lots of tests.