If regular pipeline pigging operations have not been carried out as mentioned in ‘A Good Investment’  blog or historical pigging routines have lapsed due to operational changes, it would then be necessary, prior to any inline inspection programme being carried out, to execute a specialised cleaning programme.

This type of operation is normally referred to as a ‘Progressive Cleaning Programme’ .

In executing this type of activity several different pipeline pigging tools are required to be used.

These are (but not limited too) the following types of pigging tools:

• Low density foam pigging tools
• Medium density polyurethane coated foam pigging tools (Criss Cross, Wire Brush, etc.)
• Conical cup pigging tools
• Disc type pigging tools

Both the conical cup and disc type tools can be fitted with the following attachments

• Seals and support discs
•  Cleaning brushes
•  Bypass facilities
•  Gauging plates

 Note: Tracking equipment can be fitted to any of the above pipeline pigging tools excluding the low density foams if  required.

Initial sizing of the pipeline pigging tools needs to be incremental as does the operational running sequence. This is to take into account any reduction in pipe bore that may have developed over time due to the accumulation of debris that would prove problematic should a more conventional approach to the operation be undertaken.

Carrying out this type of operation minimises the amount of debris being removed at any one time which greatly reduces the possibility of the ‘stuck pig syndrome’ and  handling difficulties of the debris removed  from the pipeline.

Progressive Pipeline Cleaning Part 2 to follow

When designing a pipeline pigging tool for a specific operation it is essential that, as a minimum, the following parameters of the pipeline are known:

·         Maximum and minimum pipeline internal diameter

·         Minimum bend radii

·         Maximum bore of branch connections

·         Operational parameters

·         Pig launching / Pig receiving facilities  (if any)

·         Pipeline medium

·         Pigging propellant

·         Service conditions i.e.             flowrates

                                                         maximum and minimum

                                                         operational temperature

Additional information will aid in the design process although non related data or data with spurious links to the operation can sometimes detract from the actual pigging requirements.

However it has to be said that too much information is better than too little as the lack of information can result in a higher probability of the pigging tool being inefficient and not fulfilling the operational expectations.

With the above information it is possible to design a pipeline pigging tool that will meet both the client’s operational requirements and comply with the manufacturers in-house design criteria. It will also ensure that the pigging tool is fit for purpose both operationally and fulfil the commercial requirements of the client.

At the present time pipeline systems are the most efficient method for the bulk transportation of both liquids and gases.

 However to maintain a pipelines efficiency the following two basic rules need to be followed.

 1/ The pipeline needs to run continuously.

 2/ Pipeline throughput must be obtained at both the lowest capital investment and lowest  operational cost.

To maintain the two basic rules a pipeline should be ‘pigged’ on a regular basis using one or more types of pipeline pigging tool, depending upon the operational parameters.

 The running of pipeline pigging tools helps to maintain the two basic rules as follows:

• Removes any harmful media.
• Removes liquid and solid debris.
• Prevents build up of flow restrictions.
• Prevents the need for long term, costly shutdown periods.

Regular pipeline pigging operations should form part of a pre-determined maintenance plan to be carried out at set time intervals and culminating in a inspection programme utilising an inline inspection tool that with provide definitive wall thickness measurement data.