Glycol Dehydration Principles

The key point of glycol dehydration principles as following dehydration process and glycol process, absorption process, distillation, heat transfer pr

1. The key point of Glycol Dehydration as following:

All unprocessed natural gas contains water, either in liquid or vapor form. The presence of water in natural gas causes two major problems in transmission lines: corrosion and hydrate formation corrosion causes pitting and damage in pipelines hydrates deposit on pipeline interiors and restrict the flow of gas.

2. Dehydration

The process of removing water from a substance is called dehydration.Although there are several methods for removing water from gas, the most commonly used dehydration method utilizes a substance known as Triethylene Glycol (T.E.G.) or simply glycol

3. Glycol 

Triethylene Glycol, T.E.G., and glycol all refer to the same substance. T.E.G. is expensive so it is efficient to remove the water,  recycling the T.E.G. to be used over and over again.

4. Absorption

Much like a sponge, glycol is used to absorb water from natural gas. By mixing together the wet gas and glycol, water is absorbed by the glycol, thereby removing it from the natural gas.

5. Distillation

In distillation, water is separated and removed from glycol by boiling T. Glycol does not begin to boil until approximately 435° F. Water boils at 212° F. Distillation of water from glycol involves heating the glycol water mixture to a temperature between 212° F. and 400° F., allowing water to separate as vapor.

 

6. Heat Transfer

Conduction is the process by which heat travels through a substance. If two containers of water one containing cold water, the other hot water are brought into contact with each other, the temperature of the hot water container will decrease and the temperature of the cold water container will increase. The temperature changes result because of heat transfer from hot to cold. By bringing together “cool” and “hot” glycol in heat ex-changers, the process of heat transfer through conduction is accomplished allowing for temperature control of the dehydration process. In glycol dehydration, it is important to maintain fluid temperatures within relatively narrow ranges, to optimize the efficiency of the process. Improper temperature control can cause glycol foaming.

7. Basic Process

There are two basic purposes of a glycol dehydration unit. The primary purpose is to dry natural gas before putting it into a pipeline. The other purpose is to remove water from glycol so that it can be used over and over again in the dehydration process.

The process, while it may seem somewhat complicated, is actually quite simple. Wet gas - that is, natural gas with water in it - has water removed from it in a dehydration process glycol literally soaks up the water, leaving dry gas. The wet glycol then goes through a process of distillation where the water is removed by boiling. The dry glycol is then sent back to function again in the dehydration of gas. In this manner, glycol is recycled.

• [accordion]
• 1. Emulsions Electrostatic Treater Principles Video
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• 2. Fundamentals of Dehydration Design
• 3. Dehydration Simulation of Natural Gas