[Gasification] Got you calculators handy??

[Art Krenzel]

Mark,

I have never heard of anyone adding extra CO2 to an operating anaerobic 
digester.

I do not think adding more CO2 would speed up or carry the AD reaction 
farther.  CO2 is a byproduct of the digestion process and acts as the source 
for the carbonate pH buffering necessary for a stable process.  Once the 
carbonate level in the reactor is established, extra CO2 would not seem to 
be necessary (or wanted) since it would serve to dilute the heating value of 
the methane being produced.

Just my 2 cents.

Art


----- Original Message ----- 
From: "Mark Ludlow" <mark at ludlow.com>
To: "'Art Krenzel'" <phoenix98604 at msn.com>; <clint at margenergy.com>; 
<gasification at listserv.repp.org>
Sent: Sunday, March 25, 2007 10:00 PM
Subject: RE: [Gasification] Got you calculators handy??


> Art,
>
> Now I'm wondering if the output of a gasifier would possibly suit the
> metabolic needs of certain methanogens. Certainly the CO2 would be useful 
> as
> would the H2 and possibly the acetic acid (if it exists).
>
> Are you aware of any such scheme for anaerobic digestion?
>
> Mark
>
> -----Original Message-----
> From: gasification-bounces at listserv.repp.org
> [mailto:gasification-bounces at listserv.repp.org] On Behalf Of Art Krenzel
> Sent: Sunday, March 25, 2007 6:25 PM
> To: clint at margenergy.com; gasification at listserv.repp.org
> Subject: Re: [Gasification] Got you calculators handy??
>
> Clint,
>
> The 22 - 30 day biogas digestion period you report is the result of AD
> operators who primarily want to use the digestion process to reduce solid
> wastes such as would be the case at a waste water facility where the gas 
> is
> flared and the facility constructed with "free" tax dollars and no focus 
> on
> ROI.  It is used primarily a means to reduce waste volume.  This is the 
> case
>
> in rural third world areas where the focus is on waste processing with
> minimal effort and getting a low cost, useable fuel.
>
> In this new world of energy concerns, anaerobic digestion has expanded 
> into
> a new role.  There are six to ten day operating AD processes which do the
> same amount of waste reduction
> by using two stage digestion, substraits and higher operating 
> temperatures.
>
> When you are talking about reducing process capital costs, moving from a 
> 30
> day process to a six day process is REAL progress and that is where we are
> today in large scale AD.
>
> There are different feedstocks which require different processing times.
> Dr. Karve has presented a starch based process with eight hours of
> processing time.  This is a specialized waste stream however one that he 
> has
>
> in good supply in his area.  This is not true in all areas however.
>
> Most areas do have food wastes, manure, waste organics, etc and nature has 
> a
>
> digestion process for them as well.  It just takes a bit longer to get the
> job done.  Humans can process food in their digestive tracts in about 24
> hours and recover only a fraction of the total energy in the food.  That 
> is
> why AD can use manure as a feedstock, take a bit longer and produce more
> energy.
>
> IMHO, I do not consider a six day processing time for AD processing of
> foodwastes, manures or waste organics to be too long to make a valuable 
> fuel
>
> product and reduce waste volumes.
>
> Art Krenzel
>
> ----- Original Message ----- 
> From: "Clint LeRoy" <clint at margenergy.com>
> To: <gasification at listserv.repp.org>
> Sent: Saturday, March 24, 2007 8:26 AM
> Subject: Re: [Gasification] Got you calculators handy??
>
>
>> Dear Tom Miles
>> Although Digestion is a possibility it is a slow methodology, taking
>> some 22 days to complete the cycle of retrieval of the Biogas. IF you 
>> look
>> to really extract the potential Ethanol carbon elements into useable
>> Ethanol
>> then look to the BTL using the known practice of the Fischer Tropf
>> process.
>> Add in some extra Hydrogen via steam reforming and you get a better 
>> output
>> of ethanol then through distillery.
>>
>> Clint LeRoy
>> Lead Consultant
>>
>>
>> -----Original Message-----
>> From: gasification-bounces at listserv.repp.org
>> [mailto:gasification-bounces at listserv.repp.org] On Behalf Of Tom Miles
>> Sent: Friday, March 23, 2007 11:24 PM
>> To: 'Michael Redler'; gasification at listserv.repp.org
>> Subject: Re: [Gasification] Got you calculators handy??
>>
>> Michael,
>>
>> The only use of the reference was to identify the yield of ethanol per kg
>> of
>> maize which is similar to other sources. Their number is 0.371 L/kg grain
>> compared with 0.406 L/kg from another source.
>>
>> The more interesting point is the energy that can be recovered from the
>> distillers grains and solubles (DGS) via digestion.
>>
>> Thanks
>>
>> Tom
>>
>>
>> _______________________________________________
>> Gasification mailing list
>> Gasification at listserv.repp.org
>> http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org
>> http://gasifiers.bioenergylists.org
>>
>
>
> _______________________________________________
> Gasification mailing list
> Gasification at listserv.repp.org
> http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org
> http://gasifiers.bioenergylists.org
>
>