Page 129 - Petroleum and Gas Field Processing

are basically similar in shape and components. Further, the same design
concepts and procedures are used for both types of vessel. Therefore, the
term three-phase separator will be used for both types of vessel throughout
the chapter.
Three-phase separators may be either horizontal or vertical pressure
vessels similar to the two-phase separators described in Chapter 3.
However, three-phase separators will have additional control devices and
may have additional internal components. In the following sections, the
two types of separator (horizontal and vertical) are described and the basic
design equations are developed.

4.2 HORIZONTAL THREE-PHASE SEPARATORS

Three-phase separators differ from two-phase separators in that the liquid
collection section of the three-phase separator handles two immiscible
liquids (oil and water) rather than one. This section should, therefore, be
designed to separate the two liquids, provide means for controlling the
level of each liquid, and provide separate outlets for each liquid. Figures 1
and 2 show schematics of two common types of horizontal three-phase
separators. The difference between the two types is mainly in the method
of controlling the levels of the oil and water phases. In the first
type (Fig. 1), an interface controller and a weir provide the control. The

Figure 1 Horizontal three-phase separator schematic of one type.

Copyright 2003 by Marcel Dekker, Inc. All Rights Reserved.