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Increasing efficiency of particle separation in natural gas cyclones using passive and active enhancements

University of British Columbia

Natural gas goes through several processes ranging from extraction, treatment, liquefaction and regasification. Among these processes, treatment, specifically the removal of solid particles, has a crucial role due to its impact on annual maintenance and efficiency of downstream equipment and processes. In essence, solid particles need to be removed at a high efficiency without increasing the pressure drop and hence power consumption in the system. Cyclone separators have been used to remove large solid particles through centrifugal forces. The main disadvantage of cyclones is their efficiency, especially for particles below 5 micrometer. Numerous studies have been conducted in improving the separation efficiency of cyclones by either spraying a mist of water or changing their geometry to increase the centrifugal forces. The main disadvantage of the majority of the geometrical modifications is the fact that they cause a significant increase in the pressure drop (at least by 15%). The mist approach, increasing the density of the particles and hence the efficiency, relies on water which adds additional cost. This research focuses on the implementation of active and passive modifications to enhance the separation efficiency of cyclones without increasing the pressure drop. The active modifications include the addition of electrostatic and magnetic forces, effects of which are studied theoretically and experimentally. The passive method involves addition of a tangential collecting chamber at the conical section. The effect of such a modification is studied thoroughly based on experiments and CFD modeling. The theoretical and experimental investigation of the electrostatic and magnetic effects show an increase in the separation efficiency of 34% and 24% for 4-micrometer particles, respectively. The results of the CFD analysis and experimental study for the passive modification (i.e., the additional chamber) suggest an increase of maximum 26% for 4-micrometer particles. The CFD results conducted for a range of particles also suggest that such a geometrical modification can increase the efficiency by 51% for 1-micrometer particles for which the increase in the pressure drop increase is only 8% (half of the minimum value reported before). These increases in the efficiency will make the cyclones a viable separator with minimum maintenance costs.

Text

2017-05-03

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/61486

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/