Here is our transcription of Cody’s great video titled Cody’s Methane Generator Part 1: Putting it Together, and embedded for you to watch, above.
Hi, everyone welcome back to Cody’s Lab. Today I’m going to be building a methane digester. I’m going to be starting with this here, which I built for one semester of college a few years ago to digest food waste and it was working as you can see.
It’s a little digestor thing here, But somebody eventually ended up stuffing it with leaves and that shut it right down. Yeah. I ended up getting it going again and here it is.
Cody Will Be Improving the Design of his Methane Generator
And I’m going to be improving the design. I was heating it with some wire. This is a nichrome wire. I just wrapped some nichrome wire around it like that.
And I actually was running 120V AC through there. Yeah, that’s obviously going to need to be fixed And also, as you can tell, it is now very cold, It’s the middle of winter. Of course, it’s always the middle of winter when I decide I want to work on something like this, So I’m going to have to insulate it rather well and possibly even put it inside the garage.
The Garage Setup for his Gobar Gas Generator
I have set it up over here. In the corner of the garage by this door, I’ll keep the door shut for now. But the idea is that I’ll move it outside of this door during summer when it’s warm enough, But since it’s winter we’ll have to heat it. I’m thinking this is what I’ll use to heat it. This is an aquarium heater. It has a thermostat in it I’ll turn it up to 94ºF.
Now I thought about just sticking it in there, then making a seal and just adding it inside the barrel, but I’ve decided that that’s a little too simple. It’s not going to work all that! Well, because the heat transfer would be terrible.
I’ve decided to use this contraption over here and then it’ll be inside of this. The idea is that this will be filled with water. The water will be warm and it’ll want to rise. It’ll come up here through this tube and go down through this.
Coil Will Dissipate Heat
Through this coil here and then all this other coil here just to dissipate heat put it in different places inside the methane generator barrel. That way, I can transfer the heat around much more efficiently Yeah. This pipe will be down inside of there and this part will be open to the air and I’ll be able to just pull this out whenever I need to –
And I don’t know if you’ve noticed this, But there’s a little disk here, which is movable Now. The idea with this is that I can take a magnet stick it in here and I can move this back and forth and agitate the slurry As you can see, And that’s It might work, but that’s the idea. This is the fill tube.
This is where I’m going to be putting the material into the methane generator chamber Just a bit down in there All the way to the bottom. There we go so I’m going to put the material down into this hole here. It has to come up high like this, I can generate a little bit of pressure This way. The fluid has to get pushed up a large distance Before the thing blows stuff all over the place.
Inserting the Heater
The heater is going to go in just like this, And this is going to come in right. There I’m going to stick this one down there and match those up, I’m going to fill this up with some cold water and test for leaks. This didn’t work at all. It leaked like crazy and the hot water wouldn’t flow through it.
I’ve decided to cut that all out and replace it with something. A little simpler, I put some dye into the water to make sure the thermal siphon was working. It seems that it was, but unfortunately, as the tubing heated up it twisted and kinked itself off.
I’ve fixed my kinked hose problem and what I did was I actually cut the pipe off and I wound the hose around it. You know out here where I could actually work with it and then I just stuck the whole thing down in there and put a coupler and fixed it back up Yeah. I think it’s working now. I got my little infrared thermometer here,
The room temperature is about 40ºF and the side of the barrel is somewhat warmer a few degrees there. This is around 90º which is what you’d expect because the heater’s on.
The pipe down in there is definitely warm. But this is what I definitely want to know. Is it warm over here? And it is, so it’s working. Excellent.
Keep the Generator Hot or it Will Not Make the Biogas
The temperature inside the barrel is still kind of cold because there’s ice down at the bottom.
Yeah. I probably ought to get that out of there, although the dye probably won’t hurt the bacteria at all. But I still need to get it out of there.
I can get this pipe to go all the way down, But yeah. I just got to seal these pieces here, I’ll use some acrylic or something to seal those up And then probably as early as tomorrow morning, I’ll be able to fill this up with material, Which is good because I’ve got plenty of rabbit, poop, Alright.
It’s the next day It looks like my glue, has cured and locked the pipes into place. Excellent. Now I’ve decided to leave the dye inside the tank, Mostly because it’s a food-grade dye and it’s probably not going to hurt the bacteria, But also I forgot to leave the heater on last night and it never melted. It’s still stuck to the bottom of the pot.
The bacteria are very sensitive, but it’s not like that’s antibacterial soap or anything. My first methane generator. I was using a five-gallon bucket and I had it full of horse and cow manure and it was working. It was making gas and I was bubbling the gas through a dish of soapy water.
I could collect the bubbles and I’d light them on fire and it would burn the gas because it would float upwards. And I was showing it to my mom and I was pushing down on the bucket to get the gas to come out.
Because I’d already been playing with it, When I released the bucket it sucked the soapy water back into the chamber And, as you can imagine, antibacterial soap doesn’t play well with bacteria, so it just outright killed it. So, definitely keep anything like that out of here, but I think the dye will be fine,
There are the rabbit droppings that I’m planning to put inside of the chamber These guys over here my partridges they’re, making a lot of noise. You might have been able to hear them in a couple of my recent videos. Their droppings can also be used for this, but it’s a little bit high in nitrogen and It might be best to mix in with some other organic material to get it to compost. Better
But just to start, I’m going to use the rabbit droppings Because it’s almost got the perfect mixture, So I’ve got a 5-gallon homer bucket here. This will be just my measuring device. I’m going to take some scoops of rabbit droppings, Just like this Now this is mixed in with some of their bedding, some wood pellets, that’s actually going to help it going to add carbon, and I think it’s actually got the carbon to nitrogen ratio perfect.
At this point, I’m only going to add in until the bucket’s about a third the way full, Maybe a little bit more. Just like this. Now I’m going to fill the rest up with water, I want to get my solids down to only about 30 %. Any higher and I’ll just end up with a huge amount of foaming and it could cause the chamber to explode if it plugs up the gas relief.
It might need a little bit more water, but you guys get the idea. Let’S get this mixed up into a slurry. This also makes it easier to move around And yeah. Here we go. Let’S get this dissolved up,
I’m just using tap water for this, or I guess in this case “ tub” water. Ideally, I’d need rainwater because it doesn’t contain chlorine, but all my rainwater sources are currently frozen, so I’m going to have to use this.
But in order to make it so it doesn’t kill out the bacteria. I’m going to add some of this de-chlorinating mixture. That’s used for fish, I find it works really well for getting rid of chlorine. It doesn’t hurt the bacteria, so a cap of that in there Just fill it up with tub water. Also this way I can add it warm, So it doesn’t take so long to heat up the chamber.
Okay, so here’s the first load of rabbit droppings, I’m just going to load this in through the service hole because it’s going to be faster. This way I probably mentioned this before, but this material – I’m adding – has the perfect carbon to nitrogen ratio.
It’s going to be perfect for growing the bacteria, but also it contains some of the bacteria that I need Cow manure would contain more, but rabbit droppings do actually contain it. Human waste or just plain food scraps are not going to contain, are not going to contain as much of the bacteria if it contains it at all. Most humans don’t actually produce the correct bacteria to produce methane,
Fortunately, I’ve got a little spill pad here. I can just clean this up when I’m done. Yeah Everything’s, looking good, I’m going to continue loading this. There are all the rabbit droppings in place. Now, it’s not quite all the way. Full I’ve left a little bit of room so that I can add more stuff. If I need to, And also If this decides to foam up, it’s got some room before it tops out.
You can see here that the stirring thing does work. Excellent. Let’s pull that out of there. Now I’m going to put this cover plate on there, As you can see it’s clear so that I can actually see through it and see. What’S going on inside of there,
The actual digestor is complete. You can see. I’ve got a tube coming up here, I’m going to run it through water and then that way I can bubble the gasses and keep it sealed. There’s definitely no soap in here. This is not the prettiest, but it’ll work.
Methane Generator Temperature Must be Plenty Warm
As you can see, I’ve got the chamber sitting on some stacks of carpeting And I’m wrapping it in some R-19 insulation. So I’m going to get this well insulated so that the heater doesn’t have to run so much. The aquarium heater itself has a thermostat that shuts off at 93ºF, which is actually a little cold. I’d rather it shut off at about 100. But it should work.
As long as this chamber is above 80ºF, it should make methane.
If it isn’t able to stay warm enough. You can see that I have another thermostat here. I can plug in another heater. If I need to and I’ll use this thermostat to regulate the temperature of the actual barrel, Alright, I’m going to finish the insulation.
From now on, I’m going to add material up to this funnel right here, As you can see, you pour water in and it displaces air.
That’s kinda cool. That means it is sealed properly. Once the digestion process is underway and I’ve got a robust bacteria population, Then what I can do is add, maybe a pint or so of material every day and take the material out over here. And just have sort of a continuous feed system going on. But it’s going to be a while before that’s up and running. Well, there it is!
It’s finished At least to the point where all I’ve got to do now is wait. It could take up to a week or more just to have the bacteria consume the oxygen that’s inside the chamber, It’ll be at least that long before this becomes an anaerobic environment.
I think what I’m going to do is I’m actually going to cut the video Make this a two-parter, I’m going to make you guys come back in a month or so when this is producing gas.