Given:
Oil gravity = 30°API, 0.875 S.G.
Oil flow rate = 5,000 bpd
Inlet oil temperature = 80°F
Water S.G. = 1.04
Inlet BS&W =10%
Outlet BS&W =1%
Solution:
1. Settling Equation. Investigate treating at 80°F, 100°F, 120°F.
2. Retention Time Equation. Plot computations of d and Leff with retention times less than 20 minutes.
The shaded area of Figure 6-13 represents combinations of d and Leff with tr less than 20 minutes.
3. Heat Required
Substituting treating temperature values of 80°F, 100°F, and 120°F and substituting initial oil temperature value of 80°F will yield values of heat required of 0, 0.86, and 1.72 MMBtu/h.
4. Selection. Choose any combination of d and Leff that is not in the shaded area. Read corresponding treating temperature.
Example solutions are:
An economical solution would be a 72-inch-diameter treater with a 20-foot coalescing section and a 0.86-MMBtu/h firetube capacity. Given the nature of empirical design procedures, crude could possibly be treated at 80°F. The additional firetube capacity will allow a temperature of 100°F if required by field conditions.
