Page 184 - Petroleum and Gas Field Processing

Equations (16) and (17) can be used for gunbarrel tanks as well. However,
when the diameter of the tank is larger than 48 in., the equations must be
multiplied by a factor (greater than 1.0) to account for short-circuiting.

Sizing Procedure
Similar to horizontal treaters, the following producer is primarily aimed at
determining the minimum size of the coalescing/settling section of the
treater and the rating of the burner.
1. Determine the optimum treating temperature that provides the
minimum lose of oil volume and quality along with a practical
treater size. If this is not available, the design (following steps)
may be executed for different assumed treating temperature and
a final decision is made based on analysis of the design results.
2. Determine the diameter of the water droplet that must be
removed [from Eq. (10) or (11)].
3. Use Eq. (16) to obtain the minimum treater diameter D that
satisfied the settling constraint.
4. Repeat the above steps for different assumed treating temperatures
and determine the values of D for each treating temperature.
5. Use Eq. (17) to obtain a relation between D and H that satisfies
the retention time constraint. Then, assume different values of D
and determine corresponding value of H from this relation.
6. Analyze the results to determine the combinations of D and H,
for each treating temperature, that satisfy both settling and
retention time constraints.
7. Use Eq. (9) to determine the heat requirement for the selected
treating temperature.

Example 2
Determine the heat requirement and the size of the settling/coalescing
section of a single-well vertical heater treater for the same conditions of
Example 1 given that the well flow rate is 1200 BPD.
Solution
Use Eq. (16) to determine the minimum diameter at the three treating
temperatures:

For T ¼ 85 F
1200 45
2 Q o o 2
D ¼ 6665 ¼ 6665 2 ¼ 6707 in:
ð
Þd m 0:2ð518Þ
D 85 ¼ 81:89 in:

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