[Gasification] [Spam] RE: Universal tar catalyst

[Kevin Chisholm]

Dear Jim

Lemme know if this helps. (See Attachment)

Kevin

jim mason wrote:
> On Dec 10, 2007 6:29 AM, Phil Marsh <marshbros at mcbridebc.com> wrote:
>   
>> Jim:
>>
>> Your numbers for biomass composition are wrong. Wood for example has a
>> carbon content of approximately 50% by mass on a bone dry basis.
>>
>>     
>
> is this the combined fixed carbon and carbon also contained in other
> HC compounds?  or just the Cs that are by themselves?
>
> can you answer the question of relative amount of energy in the C vs
> higher molecular weight HCs in the raw biomass?
>
> it is clearly time again for me to take a tour though the literature
> on raw biomass chemistry.  it seems everytime the gasifier/pyrolyzer
> designs go through another level of complexity, i need to go back in
> reconsider in greater detail the structure and composition of
> different types of biomass.
>
>
>   
>> By slow pyrolysis our carbonization system extracts very close to this
>> number using pine as a feed stock. Dr. Antal at the U of H has also
>> published many papers showing that his flash carbonization system can attain
>> very close to the theoretical maximum in carbon recovery, again this number
>> is close to 50%.
>>     
>
> can you reveal more details or drawings of your pyrolysis system, and
> its current state of dev?
>
>   
>> A 20% recovery is typical of systems such as a bee hive kiln but this is due
>> to much inefficiency in the system and a lot of carbon going into the
>> atmosphere.
>>
>> Keep up the good work.
>>
>> Phil Marsh
>> Marsh Bros.
>> (250) 569-2795
>>
>> -----Original Message-----
>> From: gasification-bounces at listserv.repp.org
>> [mailto:gasification-bounces at listserv.repp.org] On Behalf Of jim mason
>> Sent: December 9, 2007 7:25 PM
>> To: Discussion of biomass pyrolysis and gasification
>> Subject: Re: [Gasification] Universal tar catalyst
>>
>> basic biomass composition question.
>>
>> the rule of thumb is biomass is 20% fixed carbon and 80% volitiles. i
>> have never heard of your 30% volitiles number below.  can you clarify
>> this tom?  coal can range all over the place, but as an approximation
>> is considered 20% volatiles, 80% fixed carbon.  i assume these are by
>> weight percentages, but am not sure.
>>
>> when slow pyrolysed, all the carbon stays, and all the volitiles go,
>> thus the around 20% yield of charcoal making.  but then again, as
>> charcoal yield can go up to 25% and higher, maybe the fixed carbon
>> number is actually  higher.
>>
>> the figures i have never heard clearly are the relative amounts of
>> energy in the fixed carbon vs volatiles.  we can easily get an energy
>> number for combusting the carbon, but what about the volitiles?  they
>> are a huge mixed collection of things.  i'd imagine experiment would
>> be the best way to determine the energy available in them.
>>
>> so, is there a rule of thumb of energy content in biomass carbon vs
>> volatiles?  assume that all the volatiles come off as primary tars, as
>> actual fragments of the original biomass, but now as gaseous forms.
>>
>> my guess is that it is  about 40% energy in fixed C and 60% energy in
>> volatiles by weight.
>>
>> jim
>>
>>
>>
>>
>>
>>
>> On Dec 9, 2007 5:16 PM, Thomas Reed <tombreed at comcast.net> wrote:
>>     
>>> Dear All:
>>>
>>> "Tars" sure are the Achilles Heel of biomass gasification,
>>> since biomass
>>> is typically >30% volatiles with slow pyrolysis.  Those
>>> volatiles formed
>>> the basis of the development of organic chemistry from
>>> 1850-1950.  There
>>> are over 50 compounds at greater than 1% in the liquors and
>>> tars.  Great
>>> for chemistry but bad for gasification.
>>>
>>> In the 1980s many people pursued "catalytic tar destruction"
>>> and we made
>>> tests on a number of catalysts while developing our oxygen
>>> gasifier at
>>> SERI/NREL.  (Reported in our book "Air-Oxygen Stratified
>>> Downdraft
>>> Gasification" at woodgas.com).
>>>
>>> Dolomite was claimed by many Europeans to be a great and
>>> cheap catalyst
>>> for tar destruction.  It was the bottom of our list of half
>>> a dozen
>>> catalysts we tried.  I was very puzzled.  Is European
>>> Dolomite different
>>> from US?
>>>
>>> I haven't heard much about dolomite recently.
>>>
>>> Any updates?
>>>
>>> TOM REED          BEF
>>>
>>>
>>>
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>>>
>>>       
>>
>> --
>> ----------------------------------------------------------------------------
>> ----
>> jim mason
>> website: www.whatiamupto.com
>> current project: mechabolic (http://www.mechabolic.org)
>> announce list: http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com
>>
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>>
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>>     
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