Mormon Temple heat exchanger erosion-corrosion failure

Belmont, MA. Copper heat exchanger failed by erosion-corrosion at tube-sheet inlet after one year. Tom recommended 70/30 cupro-nickel; only 90/10 was available within the two-week shutdown window; 90/10 has worked for fifteen years. Sub-plot on contractor markup (16k quoted vs 6k from manufacturer).

So we can do a lot geometrically. This is just material property. There's a lot you can do — you change the diameter of the tubes, you can change the water flow rate through the tubes. I had a heat exchanger up at the Mormon Temple in Belmont. They had originally put in copper as the heat exchanger material. After one year they knew they had a little leak in there somewhere, so they took a paint stop off, and up at the tube sheet — the plate that holds all the tubes — where everything had turned because of the higher speed, they had erosion corrosion on the copper because of the solids in the water. I wanted to go to 70/30 cupro-nickel, but they couldn't get it. They had a two-week shutdown — they discovered it on the third day of the shutdown, the two-week shutdown — they had to get a new heat exchanger in so they could be up and running in another ten days.