[Gasification] Range Fuels Closing Plant

[Mark Ludlow]

Hi Andrew,

To address the exact issue you describe, designers of equipment that
incorporates the equivalent of conveyor flighting for mass transport and
processing add periodic "interrupter bars" that disrupt (mix, actually) the
mass being conveyed by the auger and prevent any co-rotation. Obviously, the
flighting itself must also be interrupted in the region of the bars.

It's common to have a large shaft core, which is generally heated as well,
to reduce the radial heat transfer distance and provide torsional stiffness
to the auger.

No one seems to know for certain how many modes of failure RF's contraption
had. From TK's description, the pyrolysis section sees overly complex and
under-designed. But it could that the conversion chemistry part of the
process was equally ill-conceived.

Mark

 

 

From: gasification-bounces at lists.bioenergylists.org
[mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of andrew
schofield
Sent: Tuesday, January 25, 2011 8:25 PM
To: gasification at lists.bioenergylists.org
Subject: Re: [Gasification] Range Fuels Closing Plant

 

Dear Thomas Koch,

  How much of  a problem for the scaled up Range Fuels plant, was heat
transfer from the hot fluid outside the auger-tubes to the celluose inside
each parallel screw-tube?
we gather a hint of the problem from your description, and Range Fuels
needing to consult you about your experience with  
hot-fluid jacketed screw-pyrolizers.

  Dr Reed said he saw the liquid fuel process working at small scale. May I
guess this success was with a jacketed single-screw?

  Inside the radiation, and convection sections of water-tube boilers steel
surface temperatures can vary widely, as water vigorously circulates inside.

Water, being more fluid than wood chips screwing along in a tube, keeps
steel temperature within certain limits throughout the entire boiler
setting. 
May we use this analogy to describe one problem experienced with Range Fuels
attempt at system scale up?

A culinary anology for heat-jacketed auger-tubes is stir-frying vegitables
in a Chinese wok. The chef adroitly presents new surfaces of the food to the
hot steel to transfer heat by conduction. The chef can only make a batch of
food under a certain size. Size beyond which he may choose to use a pressure
cooker which can feed an army.

Would not direct-contact heat exchange between the hot fluid, and the wood
be more practical at 4 ton/hr?

Andrew Schofield
Renewable Fuel Systems


Thomas Koch wrote:
 Tom
 
 Range fuel gasification technology was an externally heated
 pressuries pipe with a transport screew inside when I saw it. 
 It was very similar to the pyrolysis unit on the wiking gasifier but
 they had ideas to upscale it to 4 tons pr hour by stacking pipes with
 screew conveyers. Thinking of the challenges of making the 1 tons pr
 hour screew pyrolyser in Haslev i have doubts this principle will
 ever be competitive for energy production - even for atmospherich
 applications. Thomas Koch 

From: Thomas Reed <tombreed2010 at gmail.com>

 I attended a few of the formative meetings of Range Fuels back about 2007
when I lived in Denver.  
I have known Bud Klepper since about 1988 when we worked together on a
methanol project. 
Too bad that many $millions couldn't solve at a large scale what Bud had
solved at a small scale.  
 
Tom Reed, Pyrologist
 


Jim of All Power Labs wrote:
 thomas, why did you think a stacked array of skinny auger retorts won't
work? this seems a known solution that tends to work as far as i know. of
course the proof is in the material handling with specific fuels.

 did you find it difficult to keep the auger straight and working? difficult
to keep the heat out of the motor and bearings at the ends?

 any secret cautionary tales we should know of?

 jim

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