[Gasification] engine

[Toby Seiler]

Doug;
   
  Thanks for the information.  If the nitrogen is as high as 50%,  wouldn't the engines power be much less than if it were at 15%.
   
  You missed my point about the second stage.  The thermal energy is there, if that first stage is dry fuel and directly fires a second stage at higher temperature.  I don't mean to overdo it, but instead control the feed so stage two bed temp is 1500 or so.  Building a cracker will obviously need refractory and insulation and more gas cooling.  
   
  Thanks,  Toby Seiler
   
  

"doug.williams" <Doug.Williams at orcon.net.nz> wrote:
  
Hi Toby,

You ask:

> Is the compressability of the gas affected by the amount of nitrogen in 
it?

The short answer is no, if talking specifically about producer gas. On 
average, there can only be about 50% nitrogen in the gas. The combustible 
gas, CO, and H2, will ignite when the compression temperature reaches 1128F 
for CO, and 1060-F for hydrogen. As a mixture, it will ignite at around 
600C, and you should not forget, that you must take into consideration the 
operating temperature of the engine, as over heated engines will increase 
the risk of pre-ignition.


> If the gas had higher hydrogen content and lower nitrogen, would you 
> expect it to precombust more or less? How would >compression ratio be 
> affected?

The same answer applies as above, and the only way to prevent premature 
ignition, is to lower the compression ratio. This is why most purpose gas 
engines are around the 12.5:1 ratio.

> Jim, how about putting another stage in your setup? Setup a chamber that 
> feeds wet fuel into a hot zone created by the >hot gas of stage one, 
> under very precise manual control. Flare it off and compare. I think the 
> higher water content can be >made into an advantage in reducing nitrogen 
> and increasing hydrogen for your engine feed gas.

You cannot add water to a wood gasifier to increase the hydrogen content of 
the gas. Even at 15% moisture content, a surplus of water exists that cannot 
be cracked into H2, and this ends up as condensate when the gas is cooled. 
As Greg Manning pointed out, it takes heat energy to thermally crack water, 
nothing less than 1,000C, or all you get will be steam.

Hope this sorts your thinking.

Doug William,
Fluidyne Gasification.





 
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