The hydrocyclone separation has proved to be an indispensable tool in offshore petroleum industry. The critical problem in-offshore drilling and production is to reduce concurrently the oil and solids concentrations in produced water to acceptable levels before its reuse or disposal in marine environment. During reuse or disposal of produced water solids can cause corrosion problems to the production equipment whereas the oil-coated solids can be jeopardous to the environment. Also excessive oil concentrations have similar environmental repercussions. The solution to this impediment can not be dissociated from environmental and economic constraints. To solve this impediment the current study has hybridized hydrodynamically the design and operating conditions of the double-cone and single-cone hydrocyclone so that the hybrid multiple-cone hydrocyclone, incorporated with a peripheral aperture for solids removal, can undertake concurrent three phase separation of liquid-solid-liquid. This hybrid hydrocyclone is referred to in this study as the Concurrent Three-Phase (CTP) separation hydrocyclone system. A mathematical model based on the CTP concept and its hydrodynamics has been developed. Theoretical examples based on industrial operating conditions have been solved to demonstrate the effectiveness of this method and apparatus.
The occurrence of dispersions of oil and solid impurities within liquids is widespread and undesinl.ble. There is often the need to remove the dispersions of these impurities concurrently. Immediate cases that come to mind include reuse or disposal of produced water in offshore petroleum development and pollution control of industrial effluent.
Several investigators have developed theoretical, computer simulation and experimental models of solid-liquid hydrocyclone separation systems 1,2,3,4. Others have dealt with liquid-liquid hydrocyclones 5,6,7. The various models have featured single-cone for solid-liquid and liquid-liquid hydrocyclones and seldom touched on multiple-cone hydrocyclones. An attempt 8 was made to establish experimentally the feasibility of the three-phase separation in a twin-inlet single-cone hydrocyclone. However, little attention has been given to concurrent three-phase separation in a multiple-cone hydrocyclone.
The theory developed in this paper derives the oil and solids efficiencies of the CTP and moreso, correlating them. The internal flow touches on the relative velocities of the oil and solids in the multiple-cone CTP.
Fig 1. Available in Full Paper
Fig. 1: A Multiple-Cone CTP Hydrocyclone.
The concurrent separation of different phases can be realized by use of a multiple-cone hydrocyclone. The multiple-cone concurrent three-phase hydrocyclone in this study is a hydrocyclone with at least two cones successively architecturally structured in decreasing geometric angles downstream of the hydrocyclone as shown in Fig. 1. There are reasons for the multiple-coned CTP hydrocyclone:
As the outer vortex moves downwards, some fluid is lost inwards and the angular momentum loss in the outer vortex is compensated for by the multiple-stacked decreasing angle i.e., narrowing radius. The decrease in cone angle reduces the cut size (improves separation efficiency).
The discharge of solids is in an area of low pressure and the solids are conveyed in the boundary layer towards the apex opening and are intercepted and smuggled by the transverse orifice.
Therefore, by varying the dimensions, number of cones and cone geometry of an industrial h