[Digestion] Compressing of biogas

Tue Nov 23 13:25:42 CST 2010

Hi Brent,

I understand that it is effective to use lime water to filter CO2, but in
theory you are talking about a relatively large amount of lime water that
must be replaced constantly, causing the issues surrounding lime water
management.  Can you elaborate quantities and chemical balance of this
process?  If the goal is just to slightly reduce the CO2 content, then that
can been done in a few different ways.  How much CO2 are you removing from
the biogas, and under water lime water usage (eg, at water/lime
concentrations etc.).

I am afraid I am a bit lost regarding the shaft compression method you are
discussing here.  In what situation would one have a large shaft available?
How are you mixing the gas and liquid with no energy?  How are you then
separating them effectively?  Is this something that you are using
commonly?  I am having trouble understanding how this is all being fed into
a pipe, with no gas leaks, and then the gas is being forced downward,
somehow in sustained suspension in the liquid.  How is this "feeding" with
no energy?  What liquid are you using?  How do you have two power sources?
Are you somehow capturing the kinetic energy of the liquid in a turbine?
More information please!

Regarding the H2S, we use simple metal filters that use iron sponge, waste
metal, or cheap nails.  These have to be changed a few times per year, but
effectively manage H2S downstream of the reactor.  I am unsure of how you
would deal with that situation if there are metal components in your
reactor, like a floating drum.

Saludos,

A

On Tue, Nov 23, 2010 at 11:59 AM, bingham <bingham at zekes.com> wrote:

>  We have found that many smaller plants use a floating dome to hold the
> gas. It is fairly
> effective to use lime water as the liquid under the dome and bubble the gas
> through it.
> Much of the CO2 is removed and takes up less volume in the dome.
>
> Our primary concern is H2S. It deteriorates the steel containers many have
> used and
> posses  a safety hazard.
>
> You can compress almost any  gas  or liquid with almost no energy input if
> you have a deep shaft
> or a small mountain. Mix the gas and liquid together and feed it into a
> very strong pipe that
> in unaffected by H2S. When the mixture is at the bottom of the pipe the
> pressure is approximately
> one PSI for every two feet it has traveled down the pipe. At the bottom
> separate the liquid from the
> gas and you have two power sources. We use this method to compress gas for
> gas turbine generators.
> One of the weaknesses of gas turbines is the necessity to compress the
> fuel.
> The compressors rob power from the turbine lowering power output.
>
> Location is the key, not everyone lives next to a mountain or a deep cave,
> but the gas or pressurized
> liquid can be piped long distances because it is pressurized for almost
> nothing. You can use this
> method to replace steam in stationary steam generators or hydraulic motors.
> You are only limited
> by your imagination: your choice of the gas and liquid.
>
> Brent
>
> ----- Original Message -----
> *From:* Alexander Eaton <alex at sistemabiobolsa.com>
> *To:* For Discussion of Anaerobic Digestion<digestion at lists.bioenergylists.org>
> *Sent:* Tuesday, November 23, 2010 9:58 AM
> *Subject:* Re: [Digestion] Compressing of biogas
>
> We go around this issue frequently, as end users often come up with the
> same idea.  It is hard to tell them no, so we always take a fresh look under
> the circumstances.  At the end of the day filtration of CO2 i always ruled
> out, and that means 40% of the volume of gas you are compressing serves no
> energetic purpose.  Add that to the fact that methane does not like to be
> compressed, and we arrive again at a "no" response.
>
> The one option we always examine is the non-compressed transportation of
> large gas reservoirs.  This we have tried for distances that are too long
> for a simple gas line, and short enough to be practical by cart.  Since we
> can make durable gas reservoirs of any size and shape, this is not
> unfeasible.  Once transported, the gas is connected and used as usual, while
> a second reservoir is filling.  If you can create value for this use, and
> the transport logistics to not out-weight the value of the energy provided,
> you may have an option for success.  Others have used large truck
> inner-tubes in the same way, that are then rolled down the street to the end
> use.  I suspect that in certain locations, systems that considered
> low-pressure distribution could gain some traction.
>
> Saludos,
>
> A
>
> On Tue, Nov 23, 2010 at 6:21 AM, Vianney Tumwesige <trustvianney at gmail.com
> > wrote:
>
>> Hello Harold,
>>
>> I completely agree withYvonne, it will be economically expensive to
>> compress the gas.
>>
>> P.S. Yvonne, could you send me a copy of the paper and ppt as well?
>>
>> Best regards
>>
>>   On Tue, Nov 23, 2010 at 1:49 PM, Harold leffertstra <
>> haroldleffertstra at yahoo.no> wrote:
>>
>>>       hello
>>> Got a question from the owner of a small biogass plant in Tanzania.
>>> He is expanding a small existing biogas plant to be able to digest waste
>>> from 200 households and manure from 100 cows.
>>> He is interested in using the biogas for fueling vehicles. In our part of
>>> the world we think it will be necessary with cleaning, uppgrading of the
>>> gas and compressing.
>>> Do any of you have experience/ideas about whether this is feasible for
>>> such a small plant?
>>> 1)What is necessary to use the biogas for fueling vehicles and 2) what
>>> are the technical and economical consequences?
>>> Thank you
>>> Harold Leffertstra
>>> Senior Advisor
>>> Norwegian Climate and Pollution Agency
>>> Oslo
>>>
>>>
>>> _______________________________________________
>>> Digestion mailing list
>>>
>>> to Send a Message to the list, use the email address
>>> Digestion at bioenergylists.org
>>>
>>> to UNSUBSCRIBE or Change your List Settings use the web page
>>>
>>> http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org
>>>
>>> for more information about digestion, see
>>> Beginner's Guide to Biogas
>>> http://www.adelaide.edu.au/biogas/
>>> and the Biogas Wiki http://biogas.wikispaces.com/
>>>
>>>
>>>
>>
>>
>> --
>> Vianney Tumwesige
>>  Director - Green Heat (U) Ltd  [image: Picture]
>> P.O. Box 10235
>> Kampala-Uganda
>> 256 (0) 71 237 9889
>>
>> "The more people are self sufficient in cooking fuel, the more personal
>> and financial freedom they have." - Emma Casson
>>
>>
>> <http://trustvianney.wordpress.com/>
>>
>>
>> _______________________________________________
>> Digestion mailing list
>>
>> to Send a Message to the list, use the email address
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>>
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>>
>> http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org
>>
>> for more information about digestion, see
>> Beginner's Guide to Biogas
>> http://www.adelaide.edu.au/biogas/
>> and the Biogas Wiki http://biogas.wikispaces.com/
>>
>>
>>
>
>
> --
> Alexander Eaton
> Sistema Biobolsa
> IRRI-Mexico
> RedBioLAC
>
> Mex cel: (55) 11522786
> US cel: 970 275 4505
>
> alex at irrimexico.org
> alex at sistemabiobolsa.com
>
> sistemabiobolsa.com
> www.irrimexico.org
> www.redbiolac.org
>
>  ------------------------------
>
> _______________________________________________
> Digestion mailing list
>
> to Send a Message to the list, use the email address
> Digestion at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org
>
> for more information about digestion, see
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> and the Biogas Wiki http://biogas.wikispaces.com/
>
>
> _______________________________________________
> Digestion mailing list
>
> to Send a Message to the list, use the email address
> Digestion at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org
>
> for more information about digestion, see
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> and the Biogas Wiki http://biogas.wikispaces.com/
>
>
>

-- 
Alexander Eaton
Sistema Biobolsa
IRRI-Mexico
RedBioLAC

Mex cel: (55) 11522786
US cel: 970 275 4505

alex at irrimexico.org
alex at sistemabiobolsa.com

sistemabiobolsa.com
www.irrimexico.org
www.redbiolac.org
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