[Digestion] Digestion Digest, Vol 15, Issue 8

[prakashchandra jha]

i am livin in terai of nepal bordering india can i get adkarve,arti model
biogas digester design

prakash

On 9/7/07, digestion-request at listserv.repp.org <
digestion-request at listserv.repp.org> wrote:
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>    1. Re: Digestion Digest, Vol 15, Issue 3 (Carolyn Henri)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 6 Sep 2007 10:45:10 -0700
> From: "Carolyn Henri" <Carolyn at ResourceConsulting.us>
> Subject: Re: [Digestion] Digestion Digest, Vol 15, Issue 3
> To: <digestion at listserv.repp.org>
> Message-ID: <005501c7f0ad$ac5d42b0$0201a8c0 at OFFICE>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>         reply-type=original
>
> RE: To scrub or Not to scrub?  That is the question.  (Scrubbing biogas
> for
> use as fuel in internal combustion engine).  I have observed on several
> small farm digester systems that are using biogas to produce electricity
> with an I-C engine that there is not one right answer to this question.
>
> It appears that operationally, the decision to scrub or not to scrub comes
> down to a COST TRADE-OFF between a capital investment in scrubbing
> equipment, and an ongoing maintenance/lubrication cost for the internal
> combustion engine.   The scrub/not scrub decision must be made based on
> how
> much it will cost to install and operate the scrubbing equipment vs. what
> it
> will cost to maintain the engine in the presence of higher H2S
> concentrations in the (unscrubbed) gas.    Cost analysis should be
> undertaken only after there is a clear understanding of: 1) the chemical
> components of the gas coming from the digester in question and 2) the fuel
> quality requirements of the specific generator/engine that will be used.
>
> Capital cost of scrubbing systems for on-farm digesters (using primarily
> cow-manure feed stock) run the gamut from low-tech, in-expensive, to
> highly
> complex, enormously expensive.  I've not found any technology consistency
> AT
> ALL in this aspect of on-farm biogas clean up (in the US).
>
> The volume of gas available from the digester to run the generator, the
> energy output of the generator, and the price received for the electricity
> sold or consumed will also be factors in this decision.
>
> That's the economic view from here.
> Cheers,
> Carolyn Henri
> **************************************************
> Carolyn J. Henri, Ph.D.
> Resource Consulting Service, LLC
> 4805 Belvedere Ave.
> Everett, WA 98203
>
> Phone: (425) 290-3181
> Fax: (425) 290-7586
> Cell: (425) 308-1634
> E-Mail: Carolyn at ResourceConsulting.us
> Website:  www.ResourceConsulting.us
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> **************************************************
>
> Regarding ----- Original Message -----
> From: <digestion-request at listserv.repp.org>
> To: <digestion at listserv.repp.org>
> Sent: Sunday, September 02, 2007 9:00 AM
> Subject: Digestion Digest, Vol 15, Issue 3
>
>
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> > than "Re: Contents of Digestion digest..."
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> >
> > Today's Topics:
> >
> >   1. Re: Scrubbing biogas (Paul Harris)
> >   2. Re: Scrubbing biogas (Paul Harris)
> >   3. Re: compressing biogas (Paul Harris)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Sun, 02 Sep 2007 06:20:07 +0930
> > From: Paul Harris <paul.harris at adelaide.edu.au>
> > Subject: Re: [Digestion] Scrubbing biogas
> > To: adkarve <adkarve at pn2.vsnl.net.in>
> > Cc: digestion at listserv.repp.org
> > Message-ID: <46D9D07F.AEE7FBA9 at adelaide.edu.au>
> > Content-Type: text/plain; charset=us-ascii
> >
> > G'day All,
> >
> > As I said recently in relation to CO2, you need to look at the whole
> > system when considering H2S scrubbing. If the H2S level is such that it
> > halves engine life or causes other major problems it is probably worth
> > the effort of scrubbing, but if it just means a slight reduction in
> > engine life I would suggest leaving it in the biogas (it s a fuel, after
> > all) and doing away with all the messing around. This "engineering"
> > approach amy not satisfy the purists, but most of us want minimum work.
> >
> > Happy digesting,
> > HOOROO
> >
> > adkarve wrote:
> >>
> >> Dear Biogas Workers,
> >> All over the world, efforts are on to use biogas as fuel in an internal
> >> combustion engine. We were told by an expert that there was no need to
> >> remove CO2 from the biogas. I would like to know, how important it was
> to
> >> remove H2S from biogas. In my system, where we produce biogas from food
> >> waste, we have only traces of H2S in our biogas. Due to oxidation, it
> is
> >> supposed to get converted into S02, and by combining with water vapour,
> >> perhaps into H2SO3. This is not as strong an acid as H2SO4. The
> cylinder,
> >> piston, piston rings and valves of an internal combustion engine are
> >> supposed to be coated by a film of lubricating oil. So how much is the
> >> danger of corrosion of the engine due to sulphurous acid? There is also
> >> nitrogen in the air, which goes into the engine, and a part of it gets
> >> converted into NOx.  Does this compound get converted into nitrous and
> >> perhaps also into nitric acid? Don't these acids harm the engine?  I
> >> shall
> >> be grateful to get answers to my questions.
> >> Yours
> >> A.D.Karve
> >>
> >> ----- Original Message -----
> >> From: Duncan Martin <duncanjmartin at eircom.net>
> >> To: Warren Weisman <weiswar at yahoo.com>; <digestion at listserv.repp.org>
> >> Sent: Friday, August 31, 2007 3:39 AM
> >> Subject: Re: [Digestion] Scrubbing biogas into biomethane article
> >>
> >> > Whatever method you think of using, do reflect first on the advice
> >> > given
> >> by
> >> > Paul Harris the few hours ago to consider very carefully why you
> should
> >> want
> >> > to produce pure methane.
> >> >
> >> > Unless you want it for some kind of chemical feedstock, you
> presumably
> >> want
> >> > it as a fuel.
> >> >
> >> > If you want it as a transport fuel, it is true that storage capacity
> >> > would
> >> > be enhanced by the use of pure methane.  However, it would not even
> be
> >> > doubled, so the cost would have to be very low to make this
> worthwhile.
> >> >
> >> > Pure methane would be more energy efficient in any combustion device
> >> > BUT
> >> the
> >> > energy required to purify it might well exceed any efficiency gain --
> >> > and
> >> > that is before you even consider the cost.
> >> >
> >> > Bear in mind too that the diluent effect of carbon dioxide in
> >> > combustion
> >> is
> >> > vastly exceeded by the diluent effect of the nitrogen in the
> combustion
> >> air.
> >> >
> >> > Consider the stoichiometry of combustion.
> >> >
> >> > With pure gases:
> >> > CH4 + 2O2 = CO2 + 2H2O
> >> >
> >> > If the CH4 comes with some unwanted CO2 (lets say 2:1 for
> simplicity),
> >> > the
> >> > eqn becomes
> >> > (CO2 + 2CH4) + 4O2 = 3CO2 + 4H2O
> >> >
> >> > Now the extra CO2 is indeed a 'passenger' in any boiler or gas
> engine,
> >> > adding to the volume of the  hot gases that escape via the flue or
> >> > exhaust
> >> > pipe -and thus to the energy lost in them.
> >> >
> >> > BUT remember that the oxygen comes with a lot of unwanted gas too -
> >> > nitrogen, in a 4:1 ratio, so the true equation for the combustion
> >> > process
> >> > is:
> >> > (C02 + 2CH4) + (4O2 + 16N2) = 3CO2 + 4H2O + 16N2
> >> >
> >> > The nitrogen is just as much a passenger as the carbon dioxide is --
> >> > and
> >> > there is 16 times more of it (by volume). We all know that it is very
> >> rarely
> >> > economic to supply an engine or any boiler with pure oxygen instead
> of
> >> > air
> >> > (unless you work for NASA!), so this should be a warning that the
> >> > removal
> >> of
> >> > carbon dioxide is unlikely to make sense either. Of course, it might
> be
> >> > economic if the removal of carbon dioxide was very much cheaper than
> >> > the
> >> > removal of nitrogen. However, there is little point in considering
> one
> >> > without considering the other, since for all you know you might be
> >> > considering the less economic option.
> >> >
> >> > Food for thought?
> >> >
> >> >
> >> > Best regards
> >> >
> >> > Duncan J Martin
> >> >
> >> > Chair
> >> > Republic of Ireland Centre
> >> > Chartered Institution of Wastes Management
> >> >
> >> > ================================
> >> > CONTACT DETAILS
> >> > Duncan J Martin, PhD, CEng, CSci, MIEI, MCIWM, MIChemE
> >> > 24 Townsfield, Cloughjordan, N Tipperary, Ireland
> >> > Mobile: +353 86 8377 906
> >> > Home: +353 505 42087
> >> > Email: duncanjmartin at eircom.net
> >> > ================================
> >>
> >> _______________________________________________
> >> Digestion mailing list
> >> Digestion at listserv.repp.org
> >> http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
> >> Beginner's Guide to Biogas
> >> http://www.adelaide.edu.au/biogas/
> >> http://info.bioenergylists.org
> >
> > --
> > Mr. Paul Harris
> > Room G8, Leske Building
> > Faculty of Sciences,
> > The  University of Adelaide, Roseworthy Campus, AUSTRALIA 5371
> > Ph    : +61 8 8303 7880
> > Fax   : +61 8 8303 7979
> > mailto:paul.harris at adelaide.edu.au
> > I now use "MailGuard" - if you do not get a reply please make contact
> > again (by fax?)
> > http://www.adelaide.edu.au/directory/paul.harris
> > Member IOBB http://www.iobbnet.org/drupal/
> >
> > CRICOS Provider Number 00123M
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> >
> > ------------------------------
> >
> > Message: 2
> > Date: Sun, 02 Sep 2007 06:23:26 +0930
> > From: Paul Harris <paul.harris at adelaide.edu.au>
> > Subject: Re: [Digestion] Scrubbing biogas
> > To: "alastair ward (IGER-NW)" <alastair.ward at bbsrc.ac.uk>
> > Cc: digestion at listserv.repp.org
> > Message-ID: <46D9D146.92ED6310 at adelaide.edu.au>
> > Content-Type: text/plain; charset=us-ascii
> >
> > G'day Again,
> >
> > Yes, and one landfill site I just visited (with Caterpillar engines) did
> > not worry about H2S and got reasonable performance but another serage
> > treatment site with different engines had real trouble (and both had
> > quite similar H2S readings). You need to get all the details!
> >
> > Happy Digesting,
> > HOOROO
> >
> > "alastair ward (IGER-NW)" wrote:
> >>
> >> I read somewhere that the H2S is a problem for copper based components
> in
> >> an engine, including gaskets and some bearing surfaces so I would think
> >> that for this use scrubbing H2S is very important. I believe the waste
> >> water treatment industry has most experience with biogas engines?
> >>
> >> Alastair Ward
> > --
> > Mr. Paul Harris
> > Room G8, Leske Building
> > Faculty of Sciences,
> > The  University of Adelaide, Roseworthy Campus, AUSTRALIA 5371
> > Ph    : +61 8 8303 7880
> > Fax   : +61 8 8303 7979
> > mailto:paul.harris at adelaide.edu.au
> > I now use "MailGuard" - if you do not get a reply please make contact
> > again (by fax?)
> > http://www.adelaide.edu.au/directory/paul.harris
> > Member IOBB http://www.iobbnet.org/drupal/
> >
> > CRICOS Provider Number 00123M
> > -----------------------------------------------------------
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> >
> >
> > ------------------------------
> >
> > Message: 3
> > Date: Sun, 02 Sep 2007 06:40:39 +0930
> > From: Paul Harris <paul.harris at adelaide.edu.au>
> > Subject: Re: [Digestion] compressing biogas
> > To: Michael Smith <michael_1234 at msn.com>
> > Cc: digestion <digestion at listserv.repp.org>
> > Message-ID: <46D9D54F.FF28A1E6 at adelaide.edu.au>
> > Content-Type: text/plain; charset=us-ascii
> >
> > G'day Michael,
> >
> > One of my favourite quotes comes from Lord Thomas Dewar - "Minds are
> > like parachutes, they only function when open!" to which I add that both
> > are othen used only in emergencies.
> >
> > You need to look at each of your energy NEEDS (not wants!) and see what
> > best meets that need. By the time you cook, heat water (which can
> > possily be mainly solar hot water anyway) and a greenhouse I doubt you
> > will have too much biogas left, even using waste heat from the
> > generator.
> >
> > Liquid fuels are far better for transport use than compressing biogas
> > (but for short hauls you could use a flexible bag).
> >
> > All the best,
> > HOOROO
> >
> > Michael Smith wrote:
> >>
> >>  What a GREAT discussion. If someone will, please respond to my
> scenario.
> >>    A 10 acre plot with a home and one or more greenhouses....10x100
> feet
> >> or so. I will have access to grass clippings from commercial and
> >> multi-family area contractors 5 days a week for 8-9 months of the year.
> >> Irrigation from all is from well water and the fertilizer is the
> >> available commercial brands used in the Midwest. I would like to digest
> >> this for the fertilizer affluent and solid matter most of all. I also
> >> would like to compress the gas for intermittent use for electrical,
> water
> >> heating, or heating for the greenhouses. If feasible to power a
> vehicle,
> >> it would be nice to have the option of driving to market, to the store,
> >> or social events in a bio vehicle.
> >>   Power for the homestead is wind, battery backup and generator backup
> as
> >> well.
> >> I'm sure there are others in the U.S. with the same idea. However, the
> >> standard answer is to use it at the time it is made. Is there an
> >> economical way for this scenario to come alive?
> >>  By the way, orchard waste, as well as garden wastes would contribute
> >> also. All this organic material is FREE. In fact, it is savings to the
> >> contractors to give it to me instead of paying to dump it in a
> landfill.
> >> _______________________________________________
> >> Digestion mailing list
> >> Digestion at listserv.repp.org
> >> http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
> >> Beginner's Guide to Biogas
> >> http://www.adelaide.edu.au/biogas/
> >> http://info.bioenergylists.org
> >
> > --
> > Mr. Paul Harris
> > Room G8, Leske Building
> > Faculty of Sciences,
> > The  University of Adelaide, Roseworthy Campus, AUSTRALIA 5371
> > Ph    : +61 8 8303 7880
> > Fax   : +61 8 8303 7979
> > mailto:paul.harris at adelaide.edu.au
> > I now use "MailGuard" - if you do not get a reply please make contact
> > again (by fax?)
> > http://www.adelaide.edu.au/directory/paul.harris
> > Member IOBB http://www.iobbnet.org/drupal/
> >
> > CRICOS Provider Number 00123M
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> >
> >
> >
> > ------------------------------
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> > End of Digestion Digest, Vol 15, Issue 3
> > ****************************************
> >
> >
>
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