Aggressive Pipeline Pigging

Water pipelines often deposit solids from the water; there may be a chemical precipitation on the pipe wall, often calcium based, or pipeline corrosion developing on the internal pipe surface e.g. Fire mains and Cast iron mains.

Other sources are found in Process plants such as Pulp and paper and plants requiring cooling water circuits and waste effluent pipes. Eg Tanneries, Dairy, Power plants

The deposits hardness can depend on whether it is deposited in layers or crystalline (eg silica deposits in Geothermal pipelines).

Removal of corrosion in Oil and Gas pipelines can also require aggressive pigging techniques.

Removal of these products requires a highly aggressive pigging process to remove it.

These deposits can be centimetres thick and therefore the flow/pressure performance of the pipeline is drastically reduced often over a short period as the inside diameter of the pipeline progressively reduces.

The process is to establish a pig through the pipeline and gradually repeat pigging runs by increasing the size and aggressiveness of the pig until the pipe is clean. This procedure is often referred to as 'progressive pigging'.

A similar approach is required when performing Wax removal in Crude oil pipelines, which is often assisted by chemical batch applications.

After a pipeline is cleaned, a regular scheduled cleaning program should be adopted to maintain the pipeline design flow/pressure performance.