Page 196 - Petroleum and Gas Field Processing

Figure 3 Details of multiple-orifice plate mixers (MOM).

importance to point out that although the theory of dilution of remnant
water with fresh water is sound in principle, it can become impossible to
implement in actual application. It all depends on the intimate mixing of
remnant water with dilution water.
In the emulsion-treating step, a heating, chemical, or electrical
demulsifying aid (or a combination of them) is commonly used. The
chemical desalting process involves adding chemical agents and wash water
to the preheated oil, followed by settling, as shown in Figure 4. The
settling time varies from a few minutes to 2 h. Some of the commonly used
chemical agents are sulfonates, long-chain alcohols, and fatty acids.

6.4 ELECTROSTATIC DESALTING

In this case, an external electric field is applied to coalesce the small water
droplets and thus promote settling of the water droplets out of the oil. The
electric field may be applied in any of the following manners:
1. ac field devices for water-rich emulsions. Alternating current (ac) is
applied, which alternates the polar water molecule arrangements

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