[Gasification] Push or pull

[Luiz Alberto Magri]

Hello Doug,
   
  Yes, I understand it applies this way under normal running conditions. But are you confident regarding start-up and shut-down sequences? I believe the O2 contents in the producer gas is hard to control in transient conditions.
   
  Do you think it is safe anyway?
   
  Regards,
   
  Magri - Rio

"doug.williams" <Doug.Williams at orcon.net.nz> wrote:
  Hello Luiz,

You suggest:
>Another consideration is that any electrical device to be installed in the 
>fuel gas downstream to the gasification zone >should be explosion proof and 
>therefore quite expensive.

With producer gas, there is very little risk of explosions from electrical 
sources. The only danger is from air leaking into a suction system, when the 
gas is feeding an open flame. This causes the mixed gas to flash back down 
the pipe to the point of air entry, where it will continue to burn inside 
the pipe, or suction fan. Of course, if an engine is connected, a leaking 
valve could also trigger a flash back to the point of mixed gas entry, but 
this would create CO2, and the engine, and suction would stop. Yes you can 
fit expensive flash back arrestors, but why waste money on some thing you 
can prevent by following good sealing practice?

Remember that real danger exists if you have a gas storage facility fed by a 
suction system. Then you could quite easily generate an explosion, but other 
wise, risks are extremely small with most small gasifiers. The higher risk 
is of CO poisoning, much more subtle.

Hope this helps.
Doug Williams,
Fluidyne gasification. 



 
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