[Gasification] Boiler

[Toby Seiler]

Ben, 
   
  I worked at Bryan Steam, a boiler manufacturer... my mentor was Tom Milton, Section 7 ASME chairman for many years.  Special water tube, electric and multi fuel boilers were our responsibility, coordinating customer requirements to the production shop fabrication, all to national board certified standards.  
   
  I have to agree with Mark Ludlow that you should approach high pressure with extreme caution.  You mention hydraulic pressure check?  Are you going to do cold water to 700 or so pounds first?
   
  I would assume the upper vessel, is the superheater?  You are aware that your low square footage of surface area on the straight tubes will limit heat transfer and have calculated that into your boiler output, I hope.  You have a very small number of tubes.  The ones on the bottom will see the majority of the heat first.  Boiling across the horizontal surface on these bottom tubes will become turbulent and not flow well.  The thermal stress will be extreme from the cool areas to the very hot, causing steel or welds to fail in short order.  From the looks of that vessel, I wouldn't go beyond 50 psi until well tested.
   
  A boiler explosion is one very bad thing.  The water turns to steam, expanding to 1600 times it's former space, removing metal surroundings and flesh in its energy distribution path.  Please post pictures of the installation prior to the startup, if you can.
   
  Best regards,  Toby Seiler, STC