OT- Stupid Me

[LarryIII]

SOMETIMES MY OWN STUPIDITY AMAZES ME !!!!

I'm here at work. I know, it's Saturday morning and I'm not supposed to be here. For the last couple of months I have been doing preliminary process engineering work on a DuPont chemical plant to be constructed in Singapore. I have been sizing pipelines (both liquid, vapor, & dual phase) for a few weeks. This is a precursor to sizing all the process pumps. DuPont uses the metric system all their process work except for the piping. All the vessel, tank, pump, heat exchangers, and in-line instrument connections are in good ole' US of A inches. During the World Series I was sizing the overhead vapor lines from the distillation columns. I use process modelling software (Aspen) to obtain the flows (kg./hr. & CUM/hr.) pressure, temperature, viscosity, density,etc). I use the data from this program in an XL spreadsheet to size the lines. I use cell formulas and let the spreadsheet program do the calculations. The final two values that I want are gallons per minute for the liquid lines and cubic feet per minute for the vapor lines. Keeping the velocities at 5-7.5 gpm for liquid lines and below 50 fps (ft. per second); I use the spreadsheet to to compute transverse area of the pipelines.

There are about 1000 lines. Pipe sizes are designated by the diameter listed in inches (ie: a 4" pipe = 4 inches in diameter) Two days ago, I noticed that some of the line sizes did not seem to make sense to me. Yesterday I found the problem in the formulas.
I seem to have forgotten that there are 12 inches in a foot, and there are 60 seconds in a minute and 60 minutes in an hour. I feel like a compete fool. Well I've got to go to work now and fix all my screwups.
I'm reminded of what my old calculus teacher used to say to us engineering students, when we asked for partial credit on quizzes; "If the sign is wrong then the bridge is built upside down:.


Larry III