There will come a time when even the best maintained system will require work to ensure that its inner surfaces are properly smooth. This can be unplanned, such as due to pitting caused by chlorides attacking the surface of the stainless steel, or an agitator failing and scratching the sidewall. Or planned outages can take place, such as where the entire production chain is being upgraded and the roughness average (RA) of the surface needs to be improved to meet the new requirements.
Planned or unplanned, many operators do not even consider the possibility that the affected segments of their system can be electropolished on-site. Instead, they believe that entire sections, including tanks, must be removed and then sent out for remanufacturing off-site. While that may have been true in past years, advances in technology now allow most of this work to be performed in-place. On-site electropolishing provides the operator with a number of clear advantages in terms of time, money, disruption to operations and confidence that the job is being done to their specifications.
Electropolishing is Not Always the Whole Story
Before we begin, it is important to note that electropolishing is most often just one procedure to be performed in a sequence of processes. In the case of physical damage to a stainless steel surface for example, mechanical polishing may need to be performed beforehand. After that, electrolytic cleaning removes any debris and then the electropolishing is performed. A passivation treatment to restore the steel’s resistance to corrosion is usually the final step performed before returning the system to service. Other situations may require fewer steps before or after electropolishing is performed, electropolishing is no longer the process that the on-site vs. off-site decision hinges upon.
Time is Money
First and foremost, a key benefit of making repairs to a vessel or system on-site, is the savings in both time and money. The time lost due to taking a system offline, removing and shipping a part, and then returning it and reassembling is time that is not generating revenue. And, of course, there is the expense of transporting the section back and forth to the service company. As the axiom goes, “time is money” and in this case, both combine to negatively affect the bottom line.
The alternative, of course, is that the additional time and expense are avoided by having a trained crew performing the electropolishing on-site. Where multiple services are required, the same technicians can perform them in sequence, greatly simplifying the contracting process and eliminating the time needed for each group of technicians to set up and break down after each step.
In the past, electropolishing required electrically charging the entire structure using huge electrical rectifiers which in turn, required specialized power circuits. This was one of the driving factors for performing the service off-site. By contrast, Astro Pak has customized equipment, enabling their technicians to focus just on the area in need of treatment. This allows them to perform the work using rectifiers requiring only 30-amp power sources, something commonly available on-site. Even the most hard-to reach locations or surfaces can be processed to meet the required standards. Often, major disassembly is not required. With areas being processed a square foot at a time, only the areas in question will serviced rather than needlessly affecting the surrounding areas as well.
As a result of the service being performed on-site, the customer can monitor the entire process to ensure quality and satisfaction through every step. This allows for even more transparency and responsiveness, if for example, should any additional damage be located. As each industry has its own compliance requirements needed to gain approval from the relevant regulatory agencies, performing the work in-situ allows the customer to confirm that every critical step is performed in the correct manner.
It is also worth noting that Astro Pak technicians are highly trained and certified to perform work that meets the required industry standards, and that after the work is performed, the proper documentation needed to show compliance with regulatory demands will be properly completed.
Of course, for some operators the very nature of how tanks are installed precludes any serious consideration of removal short of a total reconstruction of the system. The majority of process vessels are not only surrounded by platforms and networks of pipes, but have their buildings literally built around them, requiring heavy machinery and a lot of deconstruction to even move. Therefore, if a vessel has been found not sufficiently release product as expected, or if the manufacturing chain is being switched to a new product, the RA can be reduced to meet the new demands without requiring major upheaval, thus saving even more time and money.
The Final Word
On-site electropolishing should be the go-to solution for most operators in a variety of situations. The multiple advantages of minimized downtime and reduced expenses, coupled with transparency and oversight go a long way towards benefiting the bottom line and reducing sleepless nights.