Kyle, Hello,
The meter system looks very interesting. How much does it add to the
cost of a biogas system?
Are you using above ground plastic tank plant, as shown in the website?
If so, the gas production will be strongly affected by air temperature.
Once the slurry temperature drops below about 25 deg.C, digestion will
take a long time to get started. It is possible that the acid formers
will be generating volatile fatty acids faster than the methanogens can
work, so the plant goes acid (and smells bad). Have you measured the
slurry temperatures of the plants that do not work well?
Methanogens take a long time to grow, especially at lower temperatures.
There is also the issue of temperature shock. When the dung is dumped by
the cow in a cold place (less than 25 deg.C), the temperature drops
(from the temperature inside the cow of about 37 deg.C). Methanogens are
affected by a temperature drop of less than 5 deg.C in one day. They do
not die, but go into a quiescent state and take time to start again,
especially if the temperature remains low.
Best wishes,
David
dav...@kingdombio.com
******************************************************
Dr David Fulford CEnv MEI, 15, Brandon Ave, Woodley, Reading RG5 4PU
Tel: +44(0)118 326 9779 Mob: +44(0)7746 806401
Kingdom Bioenergy Ltd, www.kingdombio.com, dav...@kindombio.com
Skype Identity: djfulford
------ Original Message ------
From: "Kyle Schutter" <k...@takamotobiogas.com>
To: digest...@bioenergylists.org
Sent: 18/09/2013 09:35:39
Subject: [Digestion] Introduction to Pay As You Go Biogas and a Strange
biogas startup problem
Hi All,
I would like to introduce our business to you all that we have been
working on for the last 12 months.
We have developed a Pay As You Go biogas meter that charges clients for
gas as they use it, instead of a single high upfront cost of purchasing
a whole biogas system. Our clients pay by mobile money and when they
run out of credit the meter automatically shuts off. Our system also
communicates to us by GSM on the status of the system (if there is any
leak, pH of the system, pressure, etc) every day by text message. See a
diagram of how this works here
http://www.takamotobiogas.com/takamoto-pay-as-you-go-biogas-50-unit-pilot-is-a-success/
I look forward to getting your feedback.
We have 70 systems installed in the last 4 months using our Pay as you
go meter which is a huge success for us. However, we are having a
seemingly unrelated problem with system startup and I would love to get
your advice on how I figure out what is going wrong.
When we install a biogas system we fill it with dung and water and for
systems installed in the last month we have added 5% of the total
volume as innoculant from a biogas systems that is working well. We
have made sure that the cow dung is not from cows that have received
antibiotics and the cow stalls haven't been sprayed with dissinfectant.
For the first 30 systems we installed, there was no problem startingup;
the first 30 required no innoculant and started producing flammable
biogas in 3 days. But since then, especially during the rainy and cold
season, digesters have not started up reliably. I would say that more
than 50% took more than a month to work efficiently and at least three
systems had their pH drop so low (around pH 6.0) that we decided to
replace the cow dung. For the systems that are not starting up very
well, we add 200 kg of innoculant every week until it starts working. I
tested the water that our clients use to mix with the cow dung and
found that it was rather acidic (pH 5 to pH7) but this was true of
clients whose systems were working too, so the acidity of the water
can't be the only problem.
The symtoms we are seeing are as follow:
-The pH is below 7 (but not less than 6.5)
-Some gas is usually produced but it is not flammable and usually
smells very bad (lots of hydrogen sulfide)
It seems that there could be several possibilities here:
1. There is a breakdown of the biological pathway. Either we are
missing some bacteria or there is some inhibitor.
2. There are a combination or problems involving cold temperature, rain
water and low pH mixing water (though we are still having a problem
after the cold rainy season).
3.There is some toxic substance in our tanks or the cow dung that is
causing the problem.
I look forward to your feedback on both the new meter and on the
startup problem we are having.
Best wishes,
Kyle
Founder and Director of Technology
Schutter Energy Ltd.
+254 703113383
kyleschutter (skype)
www.takamotobiogas.com
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for more information about digestion, see
Beginner's Guide to Biogas
http://www.adelaide.edu.au/biogas/
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