Page 340 - Petroleum and Gas Field Processing

REVIEW QUESTIONS AND EXERCISE PROBLEMS

1. When it is necessary to reduce gas pressure in a gas production
system, the largest pressure drop should be taken at
_____________________ to minimize hydrate formation.
2. To prevent hydrate formation, the following methods may be used:
(a) _______________________________________________________
(b) _______________________________________________________
(c) _______________________________________________________

3. Given that the hydrate formation pressure of a gas at 60 Fis
1000 psia, state whether hydrate will form if the gas is under the
following conditions:

(a) T ¼ 60 F and P ¼ 1200 psia: YES or NO

(b) T ¼ 70 Fand P ¼ 1000 psia: YES or NO

(c) T ¼ 50 F and P ¼ 1000 psia: YES or NO
4. A gas well produces with a high condensate–gas ratio:
(a) Is it practical to use methanol injection to prevent hydrate
formation?
(b) What is the reason for your answer?
___________________________________________________
___________________________________________________

5. What are the conditions that must exist for hydrate formation?
(a) _____________________________________________________
(b) _____________________________________________________
(c) _____________________________________________________
6. In a central separation and treatment plant, 100 MMSCFD of gas

containing 10% H 2 S are collected at 500 psia and 80 F. The gas is
first treated using a DEA process to reduce its H 2 S content down to
3 ppm. The sweet gas is then compressed to 1500 psia and cooled

down to 110 F. The gas is then dehydrated using a glycol
dehydration process which reduces its water content down to 7 lbs/
MMSCF. Finally, a solid desiccant process is used to further
dehydrate (polish) the gas to reduce its water content to less than
1 ppm. (See Figure 10.)
(i) Assuming that the gas is fed to the compressor at 500 psia and

80 F and that it is saturated with water vapor, determine the

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