[Gasification] the "tube within tube" hearth design

[Robert Deutsch]

Jim,

Another idea, you could weld the plate to the inner most and outer most cylinders, then pack some soft clay on top of the plate and then push the other concentric cylinders down into the clay to hold them in position.  That should work at least long enough to test your prototype.

Cheers
  ----- Original Message ----- 
  From: jim mason 
  To: Robert Deutsch ; Discussion of biomass pyrolysis and gasification 
  Sent: Friday, April 27, 2007 2:01 AM
  Subject: Re: [Gasification] the "tube within tube" hearth design





  On 4/27/07, Robert Deutsch <robdeutsch at online.com.kh> wrote:
    I like your idea a lot.... but hows about you only weld the inner most tube
    to said plate and then fix the rest of the concentric tubes with removable
    tuyauteries?  Then you could take it apart if need be.


  do you mean drilling holes and fixing tubes from the outside to the inside, with the opening into the center tube near the top of the center tube?  if so, yes, that would likely work too, but a bit more difficult to make. 

  note that only the center tube needs to be welded and sealed to the restrictor plate.  well, that and the restrictor plate seal to the outer gasifier shell.  all the rest can be approximate, as there is no through flow.  they are merely providing the structure so the char "stacks" appropriately, as well as reducing any circulation that would happen if just a conical char stack (which is good too).  even if you cut large notches in the bottom of each tube to clear the inward running tuyeres, it would still be better than just a char stack. 

  but such suggests another simplification along your suggestion.  how about this?   one tube.  and radial tuyeres.  char will stack to the conical shape above the tube.  you can add more tubes within tubes above and below as suggested previously. 

  )