Help - My gas won't burn.

[SteveH]

 If you take Alan's approach you can measure the combustibility of your gas comparatively, just using an automotive oxygen sensor & a multimeter. Set a pilot flame up a bit of pipe to give a null reading of 1.0V then add your gas through a separate jet. Not 100% accurate but will give you an idea about the calorific value (If any) of the home produced gas.

 Just an idea & I'm just at the end of a bottle too....

[JMALW]

Gee you guys thanks for the uplifting support - I'll give it some more welly and promise to let you have some photos when I get it together.

John

[Ivan]

I can't stress 'don't give up' enough. Many times I've been nearly there and yet the results seem to say I'm a million miles away. In many cases it's something ridiculously simple (like you forgot to switch something on). This forum is all about inspiring others - some pictures of your setup will undoubtedly inspire others (My cowmuck + grass clippings + water in a 20litre veg oil container inspired several people to experiment!).

You need to tell us how you're trying to burn the gas. Let's see a photo of your burner for a start. I suspect that might be something to do with your problem.

[Rooster]

Gee you guys thanks for the uplifting support - I'll give it some more welly and promise to let you have some photos when I get it together.

John

You definitely need to keep going now you've got this far!

How long has the digester been working?

What are you feeding the digester with? You mention food waste and grass cuttings but I can't imagine that the output from a 'normal' house/family would provide enough waste so how do you keep finding enough to feed it and what is it that's going in?

[JMALW]

Gee you guys thanks for the uplifting support - I'll give it some more welly and promise to let you have some photos when I get it together.

John

You definitely need to keep going now you've got this far!

How long has the digester been working?

What are you feeding the digester with? You mention food waste and grass cuttings but I can't imagine that the output from a 'normal' house/family would provide enough waste so how do you keep finding enough to feed it and what is it that's going in?

Hi Roy

It's been running 4 months.  Having a large garden with lawn has helped along with waste from other family members, plus a bountiful amount of leaves from a few sycamore trees (member of the Maple group) which contains a huge amount of sugars. Actually more than I can stuff into this 205 ltr drum.

When I feed it in I have a macerator that beats the stuff to a fine sludge - my elbow and a large stick. I give it a good paddle every other day and that really gets the bubbles going.  I was waning a bit lately so I have started to neglect it a bit but still feed it and keep it as warm as possible. I began to think, hang on a minute - I would be better off just chucking the stuff into a potbelly stove and use it as a heating source that way. Why am I making this difficult. Well I thought it might run my genny - now that would be good.
PS If it's food it goes in and any plant leaf stock etc

[JMALW]

Hello guys,
Thinking about what you said I changed the lime filled scrubber and used bleach instead - it has started to flicker already and I have no idea what's going on, but it's looking promising at last.
I connected the feed to my genny temporary and have noticed that I can turn down the amount of LPG going in. I have a hunch that assuming the calorific value is 65% of pure natural gas I may have to continue mixing a little LPG in to it. But I'm more confident now that I can make it work, thanks for your input.
To make the genny work continuously I will have to make a bigger digester since it does use quite a bit of gas, next thing will be getting enough waste to put in - restaurants, chip shops.......
John

[Ivan]

The waste product of biodiesel production - glycerine - is supposed to be very good in anaerobic digesters for boosting output. Somewhere here I did publish the optimum concentration - from memory it's optimum at 6% but anything under 12% is ok. It's supposed to speed up the gas output enormously, but I've only ever met one person who has actually tried it. The best bit is that biodiesel folk are desperate to get rid of the stuff - I bet you could do a deal whereby they'd give you a few litres of biodiesel as payment to take the stuff away.

[daftlad]

There has just been a programme on the community channel called "climate challenge" and it had a bit about the ARTI biogas digester, I expect it will be repeated sometime?
ta ta

[wyleu]

   Pictures ??....

[desperate]

ARTI biogas digester,??

That really must be a typo.


Desperate

[JMALW]

Hi
Here is a photo of my prototype prior to connection to my IBC water pump.  The small red tub is filled with wire wool to scrub out the H2S and I checked for any residue by exposing copper to the gas both before the container and after. There was a significant difference in the corrosion of the two samples. The one after showed very little tarnishing.  The grey container is an anti syphon with a one way checkvalve on the pipe to prevent any chance air may be sucked into the digester. The feed tube is simply a 100mm foul pipe bonded into the steel lid and as you can see has a test plug to seal it and act as a relief valve.  The paddle wheel I fabricated on my lathe using a stainless steel shaft honed to a fine finish and fitted with a brass compresion fitting also machined to fit the shaft and replaced the olive with graphite string, greased and tightened  onto the shaft to prevent leakage. The paddle is of the propellor design to drive the material either way in the drum.  The heat exchanger is a coil of copper pipe - I know it will eventually corrode away, however, I gave the whole interior a good coating of epoxy resin to give enough life to learn from it.  The whole system is now boxed up and fully insulated similar to the Box in the background with just access for filling and stirring.

[wyleu]

Now that gives us a perspective.

Well done.

[JMALW]

Hi
Hope you gained something from my contribution, however, I can really see what's preventing this from being really useful and I believe it's finding the ability to seperate the co2 from the methane but above all a way of fixing it in to a solid form though I'm told it may be ok since it is self sustaining. I am in the process of constructing a hydroponic green house which will grow stuff vertically without soil and use some of the Co2 if I can split it usefully. I'm seeking access to a plastic membrane that can do this, does any one know where?

[frotter]

Awesome project! Hope you keep developing it........     

 

[Ivan]

Very nice indeed. It's really inspiring. Maybe I'll have a go next year. I've always wanted to build a proper digester.

Would you mind posting a picture of your burner?

From your post, I take it that you're looking for some kind of osmotic membrane. I've never heard of one that could do that, but fuel cell membranes are designed to work with oxygen and methanol, so it might be a good starting point (expensive, though).

If you want to remove/re-release CO2, you need something which ties up the CO2 weakly, thus it's easier to reverse. The only thing I know of that does this is bubbling the gas through water - to produce carbonic acid (fizzy water ie soda). Subsequently bubbling air (low-CO2 conc) through the water will remove the CO2 again. I think you can add various things to the water to improve the uptake (my A-level chemistry seems a million years away - calcium carbonate or calcium hydroxide?). I don't think the capacity of water to absorb CO2 is very high though, so you'll need quite a lot of water. Eleanor will know. Perhaps if we shout loudly - 'ELEANOR!'