Bio-methanation at the Agricultural College of Obernai

Renewable energies except solar electric or thermal (seeforums dedicated below): wind turbines, energy from the sea, hydraulic and hydroelectricity, biomass, biogas, deep geothermal energy ...
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Did67
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by Did67 » 27/08/14, 10:32

The study for the collection of waste from school canteens in the Strasbourg / Molsheim / Obernai region, with a view to possible treatment in our station was officially launched by the Regional Council (public tender).
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by dede2002 » 27/08/14, 19:07

chatelot16 wrote:I think that the dual fuel makes an ignition more powerful than a spark to properly ignite gas full of CO2

!


Well seen! So it can also ignite a lean mixture, like a stratified charge engine.

The power regulation is done on the gas, it is an Otto engine, the "Diesel" is the ignition. A very sophisticated electronic ignition.
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by dede2002 » 27/08/14, 19:11

Did67 wrote:
With a pci of 5 kWh / m3 it increases the efficiency to 40%, and the share of gnr to 8%, on average.

There is heat to spare ...


1) I think we must be at 42/43% efficiency ...

2) GNR's share will decrease: the year for which I gave the balance sheet, the group was still at 180 kW electric. As of March 1, it is 240 kW. But the match remains the same!

3) Yes. The difficulty is to synchronize the consumption of our client ... who does not absorb all ...

In addition to the treatment of canteen waste, we are working on the idea of ​​setting up horticultural greenhouses.
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by Did67 » 01/09/14, 18:55

Bad news: the measurement of the amperages of the 3 supply phases of the agitator motors shows that the "propellers" are already worn.

We went from 35 A to .... 20 A !!!

This is the limit beyond which the digestate is no longer stirred enough to guarantee good digestion ...

It will be necessary to lower the level in the digester by pumping into the maturation tank, remove the agitators and change the propellers and go back up. There are two in the digester ...

Fortunately, it is not too expensive. Quotes are in progress.

These are SUMA agitators. This is what it looks like: http://www.alternative-energies.fr/site ... iogaz1.pdf
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by Cuicui » 01/09/14, 20:25

Did67 wrote:It will be necessary to lower the level in the digester by pumping into the maturation tank, remove the agitators and change the propellers and go back up. There are two in the digester ...
These are SUMA agitators. This is what it looks like: http://www.alternative-energies.fr/site ... iogaz1.pdf
What is the approximate diameter of this kind of propeller? What materials is it made of? What can be the cause of such heavy wear?
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by chatelot16 » 02/09/14, 13:20

propeller worn, is it hard to believe on such a recent installation?

it could also be piggy wrapped around the propellers, which decreases their efficiency and decreases the power required of the engine
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by Did67 » 02/09/14, 14:41

It is stainless steel.

I don't have the diameter.

The builder does not seem surprised!

With us, this brews a fairly thick "puree", with a lot of cellulose, which is quite "abrasive": clean your glass glasses with toilet paper, and in the long run you will see! Finally no, you will not see much!

Anyway, we'll take it out, we'll see!
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by Cuicui » 02/09/14, 19:05

Did67 wrote:It is stainless steel.
Anyway, we'll take it out, we'll see!
Maybe provide ceramic propellers?
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by chatelot16 » 02/09/14, 20:23

this gives an advantage to the mixing by bubbling compressed gas: the gas bubbles do not wear out

I almost wrote compressed air bubbling, but we are not going to send air to sabotage the methanization: we send methane: I saw this system mentioned in some description of methanizer

it seems that the mixing by bubbling consumes more energy than by propeller, but if it avoids the wear of the propellers it can be interesting

compressed gas mixing can also be a backup solution to avoid complete failure in the event of a propeller problem
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by Did67 » 03/09/14, 10:29

It surely depends on the nature of the biomass: between a slurry, very liquid, where a bubbling is sufficient and a "thick paste" such as our mixture of manure, grass, silage, waste sorting (potatoes, carrots , onions ...), there is probably a difference ... ???

It is undoubtedly also this significant presence of "fibers" which could explain the rapid wear, if it is confirmed ...
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