[Gasification] Need help from gasifier experts_Clinker formation

[Kevin]

Dear Prasad

The average fuel particle size is important for "good gas." If the gasifier design worked well with wood chips of a given size, then changing to wood pellets of a different size would be expected to result in a change in gasifier performance, similar to changing to wood chips of a similarly different size.

Wood pellets can have a different problem associated with them. In addition to the apparent difference in average particle size between wood chip and pellet fuel, there can be a hidden difference in real average fuel particle size, in that wood chips can fall apart through moisture absorption from gas circulating within the fuel bed. These smaller particles can tend to block off portions of the previously active gasifier bed, leading to channelling and non-uniform flow through the bed. This "non-uniform flow" can be "too much air in one section of the bed" (leading to very high temperatures and clinkering of ash), and other areas of the bed where there is "too little air" ( leading to tarry gas passing through the reaction zone).

Best wishes,

Kevin Chisholm


  ----- Original Message ----- 
  From: Thomas Koch 
  To: Discussion of biomass pyrolysis and gasification ; tombreed2010 at gmail.com 
  Sent: Tuesday, July 24, 2012 3:57 AM
  Subject: Re: [Gasification] Need help from gasifier experts_Clinker formation


  Dear Prasad 

   

  Thank you for a very clear pinpointing of the fundamental problem of “inventory bed” gasification technology. 

   

  If you have tars you have problems that are almost impossible to handle with in the economy a gasifier can expext to operate with in. 

   

  If you reduce the temperature you get more tars and a high char loss. 

   

  If you raise the temperature the tar problem reduces you reduce the char loss and increase the loss as latent heat in the gas - and you get klinker. 

   

  Staged gasification – Viking – Double feuer – NOTAR – TKE – Wamsler and a number other designs have managed to reduce the tar content in the gas considerably – for some close to zero – but they are all facing high temperature engineering challenges and none have proven real reliably operation for many thousand hours. 

  The challenges of all these constructions are the complex design and therefor the cost – both for building and operation. 

   

  Best regards

   

  Thomas 

   

   

   

   

   

   

   

   

   


   

  Fra: gasification-bounces at lists.bioenergylists.org [mailto:gasification-bounces at lists.bioenergylists.org] På vegne af Prasad Mande
  Sendt: 24. juli 2012 08:42
  Til: Discussion of biomass pyrolysis and gasification; tombreed2010 at gmail.com
  Emne: Re: [Gasification] Need help from gasifier experts_Clinker formation

   

  Dear gasifier experts,

  I was working on the biomass pellet trial on one of the wood chip gasifier (Gasifier design is IISc India design- Open top downndraft). I found that gasifier was able to make good quality gas when switched from wood chips to these biomass pellets. However, two major problems I came across are TAR and Clinkers. Clinkers are primarily due to the temperature in the reactor bed which is exceeding probably ash fusion temperatures for the biomass pellets I used. I want to know from you the ways to control this reactor bed temperature inside gasifier, such that I can avoid clinker formation and also reduce the temperature

   

  Waiting for the guidance from experts.  

   

  From: gasification-bounces at lists.bioenergylists.org [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of A.Saravanakumar
  Sent: Tuesday, July 24, 2012 11:00 AM
  To: tombreed2010 at gmail.com; gasification at lists.bioenergylists.org
  Subject: Re: [Gasification] Flaming pyrolysis modelling for truncated updraft gasifier

   

  Dear Booster,

   

  Warm Greetings,


  You are my GAS GURU and inspiration to us.

   

  I pray for your early recovery from the fall.

   

  I kindly request you to see through the paper and make necessary corrections in this paper in the aspect of Elsevier publications.

   

  Please check the manuscript for grammatical errors and instances of badly worded/constructed sentences and refine the language carefully.

   

  I kindly request you to correct the paper, which I have sent for your kind perusal.

   

  Thanking you

   

  Yours faithfully

   

  A. Saravanakumar

   

  On Sat, 21 Jul 2012 01:51:39 +0530  Tombreed wrote:

  >  Dear Sara

  The paper was not attached...

  Tom Reed

  Thomas B Reed




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