Integration Of The Canmet Hydrocyclone In A Conventional Heavy Oil Treatment Facility
Authors: Hashmi K.A. , Hamza H.A. 
Published: March 2010

The CANMET hydrocyclone is a high-performance separation unit developed to de-oil a variety of oily fluids, including high water-cut wellhead production. A large number of heavy oil wellhead production streams in western Canada and elsewhere contain in excess of 70% water by volume. Integration of the CANMET hydrocyclone offers a technically and economically advantageous alternative to conventional gravity-based separation units for the treatment of these production fluids. Hydrocyclones separate fluids of differing densities by means of strong centrifugal forces generated by a high-speed vortex flow within the unit. The CANMET hydrocyclone combines a number of unique design features that result in enhanced performance in a variety of applications compared to conventional designs.

Field testing has shown that oil production rates can be increased by the integration of hydrocyclone technology in wellhead production treatment schemes. Hydrocyclones are compact, have very short retention times, and reduce the processing load on downstream gravity-based separators. Important energy consumption and environmental benefits are also gained through reduced heating requirements.

Hydrocyclone Development

In the 1990s, CANMET began development work on an advanced hydrocyclone design for treating difficult-to-separate oily fluids encountered by the heavy oil industry in western Canada. A new design, called the CANMET hydrocyclone, was developed with the collaboration of Professor M. Thew of the University of Bradford, U.K. (formerly of University of Southampton), the original inventor of modern liquid-liquid hydrocyclones. Successful field testing of the CANMET hydrocyclone led to commercial installations in western Canada, and hydrocyclones are now recognized as one of the most efficient technologies for oily water separation. The CANMET hydrocyclone was patented in 1999 and is being marketed under separate licenses by Universal Industries Corporation and Krebs International.

Separation in a Hydrocyclone

A liquid-liquid hydrocyclone, as illustrated schematically in Figure 1, consists of an involute, a tapered body, and outlets for overflow and underflow. The stream of feed fluid under pressure enters the hydrocyclone tangentially and forms a high-speed vortex capable of producing centrifugal accelerations greater than 1,000 times that due to gravity. The separation forces in a hydrocyclone are proportional to the densities of the different components of the feed fluid. Solids and water, having higher densities than the oil phase, are forced toward the outer wall of the unit, while the less dense oil component is displaced toward the centre axis. The tapered body of the hydrocyclone confines the vortex flow to a decreasing radius, thus maintaining or increasing the radial velocity and, in turn, the centrifugal forces generated. The diameter of the overflow orifice regulates the rate at which overflow escapes and the purity of the oil stream. The overflow and underflow outlets can also be governed by means of pressure transducers to control the flow rate of each component stream. Water and solids exit the hydrocyclone through the underflow outlet at the end of the unit.

Factors Affecting Hydrocyclone Performance

The effectiveness of hydrocyclones depends on several factors. First, the size of the suspended oil droplets can limit separation efficiency.