[Gasification] Oxygen sensors for gasifier engines

[Thomas Reed]

 Dear Art, Andy and All:

We are developing small scale gasification power systems for biomass and 
use the 4 wire oxygen sensors to regulate air fuel ratio at the engine.  
The 4 wire sensor is heated so that the output voltage won't vary with 
exhaust temperature.  It gives a good signal, depending on air/fuel 
ratio, 0-200 mV for lean, 400-1000 for rich.  

In the feedback loop one needs a gas valve that can be controlled from 
this signal.  We have built one, but does anyone know of a simple 
inexpensive available valve for this?

Thank,

TOM REED       BEF
------------------------------------------------------------------------



Art Krenzel wrote:
> Andy,
>
> Why don't you go down to NAPA and get your self a simple exhaust oxygen 
> sensor and mount it in the exhaust pipe nearest the manifold to keep it hot. 
> With simple signal conditioning and a cab readout, you could monitor the 
> quality and/or quantity of the fuel going into the engine.  This would help 
> reduce some of the wild swings between too lean and over rich.  Who knows, 
> you may even get 50 mph out of the old buggy!
>
> Isn't technology grand?
>
> Art Krenzel
>
>
> ----- Original Message ----- 
> From: "andy schofield" <scothebuilder at hotmail.com>
> To: <gasification at listserv.repp.org>
> Sent: Thursday, October 26, 2006 7:14 PM
> Subject: [Gasification] Use Tar to Make More Gas
>
>
>   
>> Dear Ian,
>>
>> Leland has it in that the gasifier must be run at the top of the range of
>> turn-down.
>> Today I just completed a forty-mile run driving a wood-fueled 1/2 ton
>> pickup. I burned a less than 128 liters of wood-blocks.  I drained-out six
>> liters of condensate from my gas cooler. Please note that NO TARS  were in
>> the drain pan! During the run, the throttle was wide-open as much as 
>> safley
>> possible. Top speed on the flat ground was 45 mph (a new record for me).
>> Others have gone much faster! Spark advance from the driver's seat is the
>> next fabrication project.
>>
>>  There is a continuum between excess air and starved-air combustion.
>> Operate your gasifiers fast enough to be near the point where your final
>> combustion equipment can tolerate the tars that get out your hot-gas 
>> outlet.
>> Flat-head engines (good beginner's engine if you can find one) can gobble 
>> a
>> lot of tar before they won't run. Efficient over-head valve engines can't.
>>
>>  Never use a wet-scrubber. I know of a super-fund site that first began to
>> be messed-up in the 1880s only just now is remidiated and finished to 
>> USEPA
>> specification. Charcoal (for making iron), and methanol production from 
>> wood
>> was practiced at this site.  Look up "Mancelona, Tar Lake". Wet scrubbers
>> mix this kind of tar with water...then what do you do with it? Burn your
>> tars in the gasifier to produce more gas!
>>
>> Go Detroit Tigers!
>>
>> Andy Schofield
>> Great Lakes Renewable Fuels
>>     
>
>
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