Depending on the technology you have available, there are several possibilities.
My personal recommendation would be a multi step procedure:
1. Run mechanical cleaning pigs - this would clean loose scale, clean out trash
in low spots and make it easier and more economical for chemical cleaning.
2. Run chemical cleaning solution - this would remove tight/hard scale that was
not removed by the mechanical cleaning pigs. It would also leave a relatively
bare surface for next step.
3. Internally coat - in this procedure, a ball pig is inserted, followed by a
quantity of coating material, followed by another ball pig to seal. This is
then pushed through the pipe, leaving a coating which will reduce flow
resistance to a minimum and prevent further scaling.
Obviously, this would be a rather expensive procedure, but will return your line to like new or even better condition.
George McKinney
There are ways of cleaning the internally reduced bore pipeline, and among the commonly used which is economical and practical is mechanical pigging in combination with chemical cleaning.
Prior to determining which way you should be chosing is to study the physical and chemical properties of the scale buildup within your pipeline.
However, pigging may require you to do some modifications to existing pipeline such as installation of a temporary pig trap for launching & retrieving purposes. Your pipeline profile shall also be taken into consideration prior to pigging activity (bends/reducer/other limitations)
Mechanical pigging may be applicable if you utilize mechanical pig with brush or descaling capability. For the long pipeline transporting oil & gas, descaling pigs has been utilized over the years to rejuvenate the internal condition of those pipeline which have reduced bore.
However, mechanical pigging alone will not make it to the hard scale which has built up in years. Utilizing a chemical slug batched in two different pigs are one of the ways to treat the internal scale with the chemical used. These are just one of the many ways which has been used in the industry.
Regards,
Halda
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[Non-text portions of this message have been removed] Received on Tue Aug 17 07:41:00 2004
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