Finding the Right Pipe Cleaner

Issue 10 and Volume 105.

The maintenance supervisor at the municipal power plant had a water system piped with galvanized pipe that had become severely limed up. He thought he would get some expert advice on the problem. He e-mailed the professor of chemistry at the local university and explained the limed up system problems, and asked if it would be OK to use sulfuric acid to clear out the lime.

The professor wrote back, “The efficacy of sulfuric acid on deliming is irrefutable. Sulfuric acid will produce very low pH conditions. Calcium carbonate, which is very soluble under low pH conditions, will quickly go into solution. Zinc and iron are also soluble under low pH conditions, however, so this will have a deleterious effect on the system.”

The maintenance supervisor wrote back, “I’m glad to have that explained, but I am still wondering if I can use sulfuric acid to clean the pipes.”

The professor responded, “When one looks at the activity series for metals, calcium, zinc and iron are all above the hydrogen ion. It should be intuitively obvious that all of those metals will go into solution in the presence of the hydrogen ion. The depletion of the zinc will negate the anodic protection it provides for the iron. You need to seriously consider these factors when you make your choices on cleaning the pipes.”

The maintenance supervisor wrote back, “I find your comments very interesting and I am learning some new things that could be helpful in the future. I still have the lingering question, though. Can I use sulfuric acid to delime the pipes?”

The professor finally saw the light and wrote back, “Don’t use sulfuric acid, it will EAT THE HECK OUT OF THE PIPES!!!!!”

[Submitted by Power Engineering reader Gordon Lundskow.]

Editor’s note: Corporate communications has evolved to the point where it seems the highest and most common use of e-mail is the dissemination of jokes and humor stories to business acquaintances around the world. Power Engineering has collected a number of such communications from many anonymous e-mail sources and will present them in this space for your enjoyment. We welcome your contributions of engineering, technology or business related humorous pieces to [email protected], but please do not send copyrighted material.