Natural gas contains water that must be removed through dehydration. There are three main dehydration methods: direct cooling, adsorption, and absorption. Glycol absorption is most common, using triethylene glycol to continuously remove water down to 0.5 lb of H2O/MMSCF. Glycol dehydration has lower costs than alternatives due to easier regeneration and makeup of glycol, as well as less heat required per pound of water removed. Removing water prevents issues like reduced heating value, gas hydrate formation, and corrosion in downstream pipelines and equipment.

1. De- Hydration of Natural Gas
By 15PG143

2. Overview
 Dehydration of natural gas is removal of the water that is associated
with natural gases in vapor form.
 When produced from a reservoir, natural gas usually contains a
large amount of water and is typically completely saturated or at the
water dew point. This water can cause several problems for
downstream processes and equipment.
 The natural gas industry has recognized that dehydration is
necessary to ensure smooth operation of gas transmission lines.

3. Why should we dehydrate natural gas
 Reduces heating value
 Create gas hydrates
 Create corrosion
 Sales contractor specification
1. 4-7 lb of H2O/MMSCF
2. 950 BTU/SCF

4. The three major methods of dehydration
are
 1. Direct cooling
 2. Adsorption
 3. Absorption

5. Absorption of Water in Glycols
 Glycol dehydration, the most frequently used dehydration process
in the industries, is a liquid desiccant system for the removal of
water from natural gas. It is the most common and economical
means of water removal from these streams. Glycols typically seen
in industry include tri ethylene glycol (TEG), diethylene glycol
(DEG), and mono ethylene glycol (MEG). TEG is the most
commonly used glycol in industry as it is more efficient and has
high boiling point.

6. Reason of using TEG
 TEG is more easily regenerated
 TEG has a higher decomposition temperature of 404°F while DEG
is 328°F.
 Vaporization losses are less then MEG and DEG
 TEG is not too viscous above 70°F.

7. Advantages of Glycol dehydration
 Lower installation cost.
 Glycol dehydration is continuous rather than batch.
 Glycol makeup is easily accomplished.
 Glycol units require less regeneration heat per pound of water
removed.
 Glycol units can typically dehydrate natural gas to 0.5 lb of
H2O/MMSCF~ 0.01 PPM

9. Questions?