Projects

In 2006, Enterprise Products wished to build a Fractionation plant near Hobbs, New Mexico. Through S&B Engineers, I was asked to bid four towers for this project. The largest, a Deethanizer tower, was sent to me as 13’ 0” I.D x 152’ 0” long. It had a design pressure of 500 psi @ 225°F with a .125” corrosion allowance.  I noticed that the operating pressure was 265 psi and questioned why the design was so much higher. I generated a budget design as given to me and found it weigh over 650,000#. At this weight, the vessel would have to be shipped in two or three pieces and reassembled in the field. I declined to submit a quote. Two weeks later, S&B came back and told me the client, Enterprise Products wanted to know if I could design a tower that we could build and ship in one piece. I took on that challenge. First, I asked where the 13’ 0” diameter came from and was told the Koch, the tray vendor, had specified that was needed for the volume of gas that they were to process.  I then asked Koch if they had quoted their new high-performance trays. The answer was, “They didn’t ask for them”. With the high-performance trays, the vessel could be reduced in diameter to 11’ 6” I.D.  After discussions with Enterprise Products, we settled on 12’ 0” I.D. Next I challenged the 500 psi design pressure and won the argument to reduce the design to 350 psi still 85 psi above operation pressure of 265 psi. Lastly, I noted that for natural gas service, a corrosion allowance of .0625” was sufficient. Changing the corrosion allowance seems insignificant, but over the four towers involved, we saved 87,000# of steel. The tower now came in at 1.375” thick normalized SA-516-70 and the weight of the was reduced to 405,000# and could be shipped in one piece. See the above photo.