Abstract

Erosion experiments were conducted with gas-sand and gas-liquid-sand flow conditions varying air and water velocities in a laboratory scale Gas-Liquid Cylindrical Cyclone Separator (GLCC). The location of highest erosion measured for gas-liquid-sand conditions was slightly above the case for the gas-sand condition, but the magnitude of erosion for the latter case was much higher than the former. Therefore, it appears that the presence of a small amount of liquid in this geometry reduces the peak value of measured erosion. Computational Fluid Dynamics (CFD) simulations are also conducted for gas-sand flows to aid in the understanding of the particle flow characteristics and maximum wall thickness loss inside the GLCC. The results from the simulation are compared to experimental data for several conditions. A simplified erosion prediction model has been also developed to predict the erosion occurring at the inlet nozzle region of the GLCC. The model predictions agree much better with data than those previously obtained for the GLCC geometry that was based on an elbow but similar methodology was applied.

Introduction

The oil industry relies mainly on conventional gravity based vessel-type separators to process gas-liquid mixtures produced from oil/gas wells (1). After several decades of use, their technology has reached an advanced degree of maturity and their design is well established. However, they are bulky, heavy and expensive to manufacture and operate. The increasing number of offshore exploitations and the need to cut down platform and equipment costs have motivated the oil and gas industry to search for new and compact gas-liquid separators.

The GLCC (Gas-Liquid Cylindrical Cyclone Separator) (2, 3) has been widely accepted as an alternative to conventional vessel-type separators during recent years. The GLCC is a simple separator, which has neither moving parts nor internal devices. It consists of a vertical pipe with a downward inclined tangential inlet (that generally ends with a nozzle) located approximately at mid-height of the separator body, and two outlets respectively at the top and bottom of the pipe (Fig. 1a). The tangential inlet provides swirling motion to the incoming mixture. The phase separation process is enhanced by the resulting centrifugal force. During regular operation, the gas exits from the top while the liquid is collected from the bottom outlet.

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