Natural gas comes in two forms – dry or wet.
Dry natural gas is what we typically know as natural gas and is used in heating and cooling systems, for electrical power generation and in industrial applications. Higher methane content makes natural gas dry.
In comparison, wet natural gas contains a higher percentage of natural gas liquids (NGLs), such as ethane, propane and butane.
Wet natural gas is processed to separate various hydrocarbons and liquids from pure methane. Due to rigorous standards, natural gas must be processed – purified into pure methane – before it can be transported long distances. While some of this can be accomplished at or near the wellhead field processing, the complete processing of natural gas takes place at a processing plant, usually located in a natural gas producing region. The extracted natural gas is transported to these processing plants through a network of gathering pipelines, small-diameter, low pressure lines.
The actual practice of processing natural gas to pipeline-quality levels can be quite complex, but usually involves four main processes to remove the various impurities:
- Oil and condensate removal
- Water removal
- Separation of natural gas liquids
- Sulfur and carbon dioxide removal