Abstract

The flow of surfactant-stabilized oil-in-water emulsions through wedge meters and segmental orifice meters was investigated experimentally. A flow loop consisting of wedge meters and segmental orifice meters of different shapes and sizes was designed and developed. The discharge coefficients were determined for various differently concentrated stable oil-in-water emulsions. The dispersed phase (oil) concentration of emulsions was varied from 0 to 76.14% by volume. At low to moderate values of the dispersed phase concentration, the emulsions were Newtonian in nature. At high oil concentrations of 65.16 and 76.14% by volume, the emulsions were non-Newtonian pseudoplastic in nature. The single phase calibration curves of discharge coefficient versus Reynolds number are found to be applicable to surfactant stabilized oil-ill-water emulsions. both Newtonian and non-Newtonian. However, in the latter case, one needs to use the generalized Reynolds number instead of the convential one. Based on the experimental data, empirical expressions for the wedge and orifice discharge coefficients are given.

Introduction

An emulsion is two-phase oil/water system where one of the phases is dispersed as droplets in the other. The phase which is present in the form of droplets is named "dispersed phase", and the phase which form the matrix in which theses droplets are suspended is referred to as the "continuous phase". Emulsions of oil and water are widely encountered in industrial applications. For example, a significant portion of the world's crude oil is produced in the form of emulsions. It is believed that the emulsification of oil and water occurs in the formation near the well bore where the velocity gradients are very high. The high shear in the production facilities such as pumps, valves, and turns also favors the formation of the emulsions [1].

The application of emulsions in industries other than petroleum are numerous; many products of commercial importance are sold in emulsion form. The non petroleum industries where emulsions are of considerable importance include food, medical and pharmaceutical, cosmetics, agriculture, explosives, polishes, leather, textile, bitumen, paints, lubricants, and polymer [1].

The measurement of flow rate of emulsions is required in many of the industrial processes where large volumes of emulsions are bandied. However, despite the industrial importance, little published work is available on metering of emulsions. It is due to this lack of information that the present work was undertaken. The major objective of the present work was to investigate the applicability of wedge meters and segmental orifice meters to emulsions metering.

The wedge flow meters consists of a wedge-shaped constriction placed in the path of fluid flow to create a differential pressure as shown in Figure la. The restriction is characterized by the Z/D ratio and the wedge angle, where Z is the height of the restriction, and D is the pipe inside diameter. The segmental orifice meter (see Figure 1b) is a special case of a wedge meter having a wedge angle of zero. Wedge meters and segmental orifice meters have many applications in the Petrochemical industry and have many advantages as follows: (a) they can be used to measure the rate of flow in either direction,

This content is only available via PDF.
You can access this article if you purchase or spend a download.