1. Chapter 1 Mid Fundamentals
Gas Processing I NGT 140
Chapter 1 Mid
Fundamentals
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2. Miscible (text p. 3 & glossary p. 173)
Miscible liquids - are liquids with different specific gravities that can be mixed together without separating.
Capable of being mixed. That is capable of being mixed in any ratio without separation of the two phases (as gases or liquids).
Miscibility – a property of liquids that is evidenced by their ability to mix.
Immiscible – liquids that do not or cannot mix together. Example: the lighter liquid floats to the top. Like oil and water. Thus this free water can be drained from the bottom of a tank. Example – Gas Separation Unit (GSU)

3. Miscible (text p. 3 & glossary p. 173)
All hydrocarbons in a gas processing plant are miscible with one another, but are immiscible with fluids such as water and glycol.

4. Solubility
Of a gas or liquid is the degree to which the substance will dissolve in a particular solvent.
BUT – glycol is “slightly” soluble hydrocarbons.
Care must be taken when using glycol is used to dehydrate hydrocarbons as it can be slightly contaminated and thus degraded. (text p. 4)

5. Ideal Gas Law
Gases can also be called vapors.
Pressure is caused by moving gas molecules colliding with the walls of the containment vessel.
Heated gas molecules move faster.
Cooled gas molecules move slower.
Reduce pressure by decreasing the number of collisions of the molecules (cooling) or increasing the size of the containment.
Increase pressure by increasing the number of collisions (heating) or decreasing the size of the containment.

6. Ideal Gas Law
All gases occupy an equal volume at the same conditions of temperature and pressure.

7. Liquid and Gas Phases (fig. 1.3 & gloss. 181)
Molecules of a liquid are held together by a natural attraction.
In a partially filled vessel – when heat is applied some gas or vapor molecules will escape (evaporation).
Likewise at the right temperature some gas molecules will return to the liquid state or phase (condensation).
Vapor pressure – pressure exerted by a substance when the substance and its vapor are in equilibrium. (fig 1.5)
Equilibrium is established when the rate of evaporation of a substance is equal to the rate of condensation of its vapor.

8. Liquid and Gas Phases Liquid expansion or volume expansion (p. 6)
When a liquid is heated and it expands in all directions.
If the liquid is contained in a pressure vessel the vessel could rupture.
GPSA recommends – when filling pressure vessels above 0 F degrees – leave at least 20% of the vessel to be empty to allow expansion.

9. Liquid and Gas Phases
Boiling point – when it’s vapor pressure equals the pressure in the vessel.
For each temperature there is a pressure – vapor pressure – at which the liquid will boil. Fig 1.7
Hydrates – Icy mixture of hydrocarbons and water that can form at temperatures as high as 80 degrees F. (p. 7)
Hydrates can be controlled by
Injecting methanol or glycol into the fluid
Increasing the temperature of the fluid.
Lowering the pressure
Comparing physical properties pg. 8 & 9
Mole is the base unit used to express the mass or amount of a substance based on its molecular weight. Pg. 10