Abstract

The CANMET hydrocyclone is high-performance separation unit developed to de-oil a variety of oily fluid streams, including high-water-cut wellhead production. A large number of heavy oil wellhead production streams in western Canada contain water in excess of 70% by volume. In conventional processing schemes, the production stream is chemically treated and heated in a gravity separation vessel to produce a concentrated oil stream, which is further treated in a heater treater unit to reduce the water content to achieve pipeline specifications. The CANMET hydrocyclone offers a technically and economically advantageous alternative for the treatment of these production fluids.

Hydrocyclones separate fluids of differing densities by means of strong centrifugal forces generated internally without the use of moving parts. The CANMET hydrocyclone combines a number of unique design features that result in enhanced performance in a variety of applications compared to conventional designs. These patented features include balanced multiple inlets that improve separation efficiency in all applications, an adjustable overflow orifice that allows the operator to optimize unit performance for changing feed characteristics, and the capability to remove suspended solids in a separate stream.

This paper discusses important features of the CANMET hydrocyclone and how it can be integrated with conventional equipment to enhance separation efficiency and reduce treatment time in existing facilities. Results from field trials are presented to show the benefits that can be achieved by integrating the CANMET hydrocyclone into conventional treatment scheme.

Introduction

Oil recovery techniques often yield fluids containing large proportions of water and solids. Effective removal of these contaminants is essential to meet specifications (0.5% BS&W) for pipeline transportation of crude oil product. The free-water knockout vessel (FWKO) is the standard unit used for removal of the solids (sand and similar particles) and bulk water from heavy oil fluids before they are treated to pipeline specifications in a heater treater. An alternative to the FWKO vessel, the liquid-liquid hydrocyclone, offers effective separation at a substantially lower cost with the potential to handle a wide range of separation problems.

The first liquid-liquid hydrocyclone design was developed by Prof. Martin Thew at the University of Southampton, U.K. in the late 1960s, which began an evolutionary process of technological advancement in oily water separation that has continued ever since. In 1983 a single hydrocyclone test unit designed by Prof. Thew was used in oil recovery trials in Australia and proved extremely successful. The demand for hydrocyclone technology has been growing ever since that initial success. As a result of efforts by government and industry, the hydrocyclone has come to be recognized as one of the most efficient methods of oily water separation in the world. In the 1990s, in collaboration with Prof. Thew, CANMET began development work on an advanced hydrocyclone design that would be capable of treating difficult-to-separate oily fluids encountered by the heavy oil industry in western Canada. Successful field testing of the newly patented design known as the CANMET hydrocyclone in Saskatchewan and Alberta eventually led to commercial installations in western Canada.

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