Distillation column manufacturing - right grade of steel?

[SterlingPower]

Hello,

We have been quoted for 125k for a 20ft x15 ft sq distillation tower
which isn't too bad I feel. But I was wondering if it would be cheaper to get my own team together and make it ourselves.
Since steel isn't all that expensive to start with and I am working on $25 hour for each welder its a bit perplexing as to where the money goes.

We haven't manufactured something like this before and would like to ask here, the grade of engineering steel and ideal methods for construction would be most helpful

Sterling Power

 

[unclesyd]

It is a little more involved that getting a bunch of welders togather grabbing some steel plate having it rolled and sticking it togather.
To make a long story short you have to know the Pressure Vessel Code used by your jurisdiction. Once you have that you have to have a design for the column by a competent engineer well versed in the approved code, preferably by a licensed Proferssional Engineer. Have your shop recognized as a code shop by the local jurisdiction. Once you get your shop certified you have to prove that your welders can weld by testing each one to a code specified test. You have to set up your materials of construction where you can track each plate pipe, flange, etc. Once you start construction you have to find a vendor that will roll the plate at the same time keeping track of each lot of material. Now you can get started preparing the rolled plate for welding using the proper weld detail. One would normally have a boiler maker to align everything prior to commencing welding. After welding you have to do non-destructive testing called out by the code of construction. Once the NDT is complete you will have to hydrotest the column. After the passing the hydro you will have to clean and paint the column.

You can build a column without all this, but you put your self in one hell of a liability box. You have to realize that you quote come from a vendor that has done all qualification and certification so all he has to do is build the column and keep the appropriate records of same.

 

[stanweld]

In addition to comments by unclesyd, you have to purchase the material and you have to have a contract with and AIA and pay for the AI's services.

 

[StoneCold]

Sterling power.

Something you might want to do is shop it around a little bit.
Something else to consider is to specify what material you are trying to produce, purity, etc and let the column guys give you a design. Copying an old existing column might not be the cheapest way to get the product you want.

Regards
StoneCold

 

[MJCronin]

Sterling....

I am guessing here, but I assume that you are replacing an existing ditillation column, and your existing unit has no ASME code certification (commonly called a "West Virgina Special" here in Pennsylvania.)

Distillation implies heat.....and increased pressure.

What is the operating pressure for the column ?

Do PIDs exist and has there been a HAZOP on the process ?

After the accident, the first question from OSHA will be "Where is the ASME Stamp and who did the process HAZOP ?

There has been lots of fun in the past with homemade pressure vessels....

In a textbook case, used in Universities as a classic "bad example" DD Williamson certainly found out.

http://www.csb.gov/assets/document/DD_Report.pdf

(Check page 47 of the report)

Several "homemades" have decided to play booster rocket.....all of thier own accord.

Let us know of your final decision........