Processing is rarely steady-state and gas and liquids are not evenly distributed throughout the pipeline. As liquids collect in pipelines, they reach a level in which they get picked back up in the gas, but travel as large "slugs" with dis-proportionally large amounts of liquids can hit equipment or processes and overwhelm the design. The same can happen in liquid systems where degassing can occur and a system can push a large amount of gas or vapor lock a system. A slug catcher, located between the outlet of the pipeline and the processing equipment, is a vessel with sufficient buffer volume to store the largest slugs expected from the pipeline system. This allows the liquid and/or gas product to be moved to the processing facility at a controlled rate.
Accelerated Process Systems manufactures both "harp" or "finger" style as well as conventional vessel slug catchers. They differ in terms of liquid capacity, micron separation capability, and transport and installation requirements.