[Stoves] answers from Alexis

[Ron Larson]

Alexis - I am taking the liberty of responding to you with a cc to the full "stoves" list.  Thanks you for your full and complete response.  I add a few [Notes in bold] below and merge one later answer from you into the body of the following.   Ton
  ----- Original Message ----- 
  From: Alexis Belonio 
  To: Ron Larson 
  Sent: Sunday, April 01, 2007 9:55 PM
  Subject: Re: my answers


  Dear Sir, 

  Here are the answers to your queries:

  YOURS:  I found this article most interesting.  Congratulations.  Because I have been away from "stoves" for some time,  I apologize if some of my following questions are old ones.  I have also just  read your very complete 155 page manual on an earlier fan-powered model and congratulate you on that.  

  MINE: Thanks and Glory to God!!

  YOURS:  Q1.  I was very surprised that this larger power, hydrogen-forming unit did not have a blower (apparently);  it seems to be natural convection (True?).  Is this (presumably an advantage) directly related to your introduction of the "steam tank"?  Is this a brand new invention - or based on some earlier product?

  MINE: Yes the super turbo doesnt need a fan.  It created flow due to the steam generated in the tank.  This is not a brand new invention.  There are lots of people doing this in stove and in steam turbine.  In China they are using the steam for improving the burning of wood fuel in the stove.  In gas turbine they use it to clean the gas during combustion of fuel.

          [RWL1:  Can you cite a reference in the stove literature?  This is new to me for stoves (especially your type of combustion stove), although I have seen use of steam in larger gasification units.  ] 

  YOURS:  Q2.  You state that your efficiency is 15.2%.  From your longer 2005 manual, it seems to me that your efficiency computation is not taking account of the energy in  the "waste" charcoal (which is in this case 25% [or I also see 35% in the manual]).  I think you are thereby appreciably understating the efficiency of both the older model and perhaps the new one.  Might I have missed something?

  MINE:  The 2005 gasifier is basically purely gasification of fuel.  The super turbo basically is direct combustion.  The two are different!  The gas produce from the gasifier (the older one) is a mixture of CO and H2 plus other while the super turbo is CO2 plus hydrogen.  Efficiency of the stove basically low compared when the gasifier is to be used for drying or direct firing.  The 35% you mentioned in the old one is the percentage char produced.  That is entirely different from efficiency.

          {RWL2:  My point is that char output and efficiency are (closely) related.  When talking about efficiency, even for stoves that have little charcoal production, the standard efficiency formulas all you to deduct the energy content of the produced char  (and I think those formulas are wrong).  So I urge you to weigh the charcoal and your reported efficiencies will be m comparable to those of others.]

  YOURS:  Q3.  My own interest is in the use of the "waste" charcoal - for "terra preta" purposes.  Any tests yet in that direction?  

  MINE: Rice husk when gasified can produce as much as 40% char but remember that rice husk char contains a lot of silica.  The heating value may reach as high as 3500 kcal/kg depending how you pyrolyze your husk.

          [RWL3:  Agreed.  your value of 3500 kcal/kg is about 15 MJ/kg - which are units I prefer.  About half  the 30 MJ/kg that we often talk about for char.  But there is talk about silicon perhaps being valuable as a soil amendment (of course not for the CO2 climate issues that are driving my interests  now).]

  YOURS:  Q4.  There is a large pipe coming out to the right of your diagram about half way up - but no labeling.  What is its function?

  MINE:   The pipe that is halfway in the diagram is the entrance for the ignition of fuel.  This makes ignition of rice husk fuel more convenient.

      RWL4:  I have taken the liberty to include your modified separate answer.  Thanks.

  YOURS:  Q5.  It appears that you are able to have continuous feed with your two conical shapes, and the (very clever it appears) means of clearing the char.  But it is not obvious what is happening to allow this continuous feed of fuel. A bit more description possible?

  MINE: There is a lever that scrape the char to discharge it from the bottom of the hopper.

          [RWL5:  Thanks.  I had been assuming this new unit was more like your 2003 charcoal-making stove.  Bottom lighting makes sense now, but I am still surprised that adding steam helps so much with a clean burn.  I am still uncertain how the continuous feeding of fuel is accomplished (but thanks for the added detail on removing charcoal.   Do you get mostly ash if you don't use the scraping lever often?  When  the lever is used and you drop char to the lower container,  I would think the char could continue to combust.  How do you prevent that?  It would seem that this design would work for a variety of fuels (maybe limited to small size?), not just rice hulls.
  Not understanding yet your feed mechanism,  I can't tell, but do you think it might work with wood pellets?]


  YOURS:  Again - thanks for sending in this most interesting new approach to achieving a clean burn.  I am very impressed by the caliber of your work.

  MINE:  Thanks and Glory to God!  He reveals it to us so that we can have solution of finding ways where we can generate power without polluting our environment.

  Good day and God bless!!!

  Alexis


          [RWL:  Again thanks for nice work and nice reporting.    Ron]