Pipeline Cleaning

There are generally three main reasons for cleaning an active pipeline. They consist of improving the line flow efficiency, improve or insure good data on inspection tool runs, and to improve the results of chemical programs to increase the lifetime of the pipeline.

The flow efficiency of a pipeline as far as cleanliness is concerned, is based on the internal diameter of the pipeline and the friction that the pipe wall surface applies to the product moving through it. By pigging the pipeline routinely, the internal diameter of the pipeline can be maintained. However sometimes the mechanical force of the pigs to the pipe wall surface is not enough to remove the materials that have built up on the walls, and therefore a fluid to break down the contaminant and carry it out of the line is required. Also the presence of a contaminant on the pipe wall can create a reduction in efficiency even though the ID of the pipe has not been substantially reduced.

The surface roughness of these materials can tend to apply friction to the product being transported through the pipeline and create a backpressure. The cleanliness of the pipeline is a big concern when it comes to running In-line Inspection Tools, due to the high cost of a miss-run or damage to the Inspection Company’s equipment. The safe passage of these pigs and insuring that the best possible data is recorded is very important.

Debris on the pipe wall surface can cause sensor lift-off, which can have detrimental effects on the tool being able to accurately measure an anomaly in steel. It can also pack into the ILI tool mechanical components causing problems in it, being able to navigate through various components of the pipeline system.

There are several methods of Pipeline Internal cleaning which should be selected on the basis of fluid application.

Chemical cleaning is done by flow of the hydrochloride acid with water mixture for rust removal, a neutralizer and a passivator, all are separated by pig through inside the pipe line and achieved bright metal finished inside the pipelines.

There are some important chemicals which are used in the cleaning process, sodium hydroxide (NaOH)- 0.05 %, sodium carbonate (Na2CO3)-0.3 % Tri-sodium phosphate (Na3PO4)-0.3 %, detergent-0.05 %. Equipment required for chemical cleanings include: a storage tank for storing and mixing of chemicals, a pump set for mixture circulation inside the pipeline, jump over to connect the pipeline and chemical mixture with water. By adding pipeline-cleaning compounds that have been specially formulated to address each of these issues, the physical limitations of the design of cleaning pigs can be overcome. As an added benefit these solutions can actually reduce the amount of friction on the pig allowing the pigs to have a longer effective life.