7 Tips For Cleaning Heat Exchangers
Keeping heat exchangers clean is a vital aspect of routine maintenance, yet maintenance is often the poor relation of a refinery and where production often has the final say. Fouling will always build up and will continuously cost money in lost energy, asset life, run time, etc. This is especially true of exchangers upstream of your fired heater (the biggest consumer of energy within your plant) as they are fired harder to compensate for the lack of heat exchanger performance.
Shutdowns due to heat exchanger failure and fouling costs hundreds of thousands, even millions of dollars a year – many times the pin prick cost of the most technically intensive cleaning procedures.
1. To Water Jet or Not to Water Jet
We have a proven 3-stage cleaning process that includes multi-lance ultra-high pressure water jetting (<40,000 psi @ 2 g.p.m.). Polishing and projectiles should be the first choices for light to heavily fouled heat exchangers, proven to be highly effective and environmentally friendly. Whilst slightly costlier, it is still better value for money as clients achieve a higher degree of cleanliness, which will extend run time – providing, of course, that operators can prove their competence!
Using as little as 4 litres per minute (1 g.p.m.) and pressures up to 60,000 psi, it is, contrary to popular belief, one of the safest cleaning methods available in the trained hand. This will lower maintenance costs by negating the need for hazardous chemical disposal services, and not least recleaning of the exchangers when testing the asset for integrity using IRIS or Eddy Current.
“The temptation to “clean” heat exchangers using traditional and inadequate equipment or chemicals is all too common if left unsupervised by your site engineers, and can lead to damage of tubes and an unclean exchanger” says Jon Camp, MD at Tube Tech. “After 35 years in the industry, TTIL firmly believe that a combination approach of 3 specific cleaning systems that include Ultra high-pressure water, Mechanical high-speed rotary polishing and rotary projectile methods should be your choice of cleaning, having proven to be quicker than a lancing method by removing the right fouling matched to the right technology… The cost of making the wrong choice is enormous, especially if you have to wait till the next shutdown in 4 years!”
2. Keep Cleaning on Schedule
Routine maintenance should – as the name implies – be performed according to a schedule, but with the right cleaning techniques (and not wait until deltaP or increased energy consumption highlights the need for cleaning). Depending on the specific heat exchanger in question, correct timings must be defined well in advance. The difficulty however, is that neither manufacturer nor onsite maintenance teams will know of or have direct cleaning experience, thereby having to leave the choice of cleaning method to the contractor, hoping they make the right choice of cleaning method (which often reverts to what “they’ve always done” without too much innovation).
Routine cleaning (“using the right method chosen for the right fouling”) saves an enormous amount of downtime. If done correctly, it will prevent deposits forming as quickly next time, reduce underscale corrosion, extend asset life & run time and enable inspection first time, every time without the need to re-clean.
Combining the cleaning with the inspection ensures equipment is fully operational and meets regulatory standards first time without delay. Ensure the cleaning contractor and inspector work closely together to understand “how clean is clean”.
“If your plant does not already have a routine heat exchangers regime, implement one immediately, and where we can help.” explains Jon.
3. Why dismantle when you can clean in-situ without Pulling
Robotic heat exchanger cleaning techniques allow tube cleaning and inspection maintenance to be performed without pulling exchangers. This is a brilliant cost saving for plant operators looking to minimize downtime & associated costs with scaffold, bolts, gaskets, 3rd party costs, risks of pulling, etc.
Some specialists undertake heat exchanger cleaning at their own facility, incurring additional & unacceptable downtime. If your current contractor is unable to clean your heat exchanger in place, do not hesitate to seek a second opinion from other service providers who may have alternative cleaning methods that can complete the job on-site, reducing the time to project completion.