# Biogas questions



## Beachman! (Mar 26, 2020)

I've seen videos of how to set up biogas digesters with IBC totes. I like the idea of being able to essentially compost anything, my understanding, and setting it up doesn't look that hard. 

My questions are: 1) Can biogas be used with natural gas systems, which I have currently? 2) If so, how do I hook up to the natural gas line? 

I have looked into this with Building Code, and I haven't seen any limitations, so there's that. But thanks for all your help!


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## Cabin Fever (May 10, 2002)

Biogas is very "dirty." When I say "dirty," I mean there is a lot more in the gas besides methane, like sulfides, nitrous oxides, moisture, etc. When these gases burn together they create acids that will quickly corrode your gas-burning appliances.


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## Beachman! (Mar 26, 2020)

So is it not worth the time? Are there any ways at home to clean it? Could I use it for specific appliances, is outdoor grill or fire pit?


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## Cabin Fever (May 10, 2002)

Beachman! said:


> So is it not worth the time? Are there any ways at home to clean it? Could I use it for specific appliances, is outdoor grill or fire pit?


Anything metal, like tubing, sensors, orifices, would corrode quickly.

There may be ways to clean the biogas using dessicants and catalysts, but it's probably not worth the time and money.

What you might want to look into are the ovens/stoves that use biogas in third world countries (eg, India, Africa). I believe everything is made from stone, clay, plastic tubing, and heavy cast iron.

The other problem with biogas is there is no good way to store and appreciable amount of the gas. It is generally used as it is being made.


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## Bearfootfarm (Jul 13, 2006)

I saw a Youtube where they mixed a batch of manure with water in a five gallon bucket and put a lid on it.

The lid had a hose connected to an inner tube that was used as a bladder to store the gas. There was a "T" fitting and some shut off valves to route the gas to a burner and some lights. 

I don't know how much pressure they were getting, and it took a few days with the bucket sitting in the hot Sun to fill the tube.


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## Cabin Fever (May 10, 2002)

When I first started my career at the University, I was involved with a biogas demonstration study on a hog farm. We would load a few 100 gallons of hog manure into a large silo sized digester every few days. We heated the digester by continuously circulating hot water from a hot water heater thru a heat exchanger in the digester (so we were using electricity to heat the digester).

The gas from the digester was routed to a huge military surplus poly bag. The bag was the size of a one-car garage. (We had to stake the bag to the ground or it would blow away like a tumbleweed.) It took about a day to fill the bag with biogas. The idea was to use the gas to run an electrical generator. 

I don't remember the wattage of the generator, but it was big. It was powered by a 4-cylinder gasoline engine that we converted to use methane. We had tubes to clean the gas that had some kind of catalyst in them (Copper wool maybe?) and a dessicant. We tested the generator several times and it worked fine.

At any rate, one day we offered a field day and people could come out to see set up. The professor I worked for explained the study. Then came the big part of the show. I started up the generator and it ran and produced electricity! It ran for about 15 minutes and the huge bag was empty! One of the attendees asked the prof, "What do you suppose the gas in that bag would be worth?" The prof replied, "Less value than a gallon of gasoline." 

The conclusion of the study was that you had to size your digester to produce biogas at whatever rate you wanted to use it at because you really can store the gas.


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## damoc (Jul 14, 2007)

I built a methane digester in a pair of 50 gallon drums using rabbit and chicken poo. the sealed drum was the digester the other drum had the methane bubble up through water which removed much of the sulpur compounds and then was stored under a plastic bucket.


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## damoc (Jul 14, 2007)

I managed to use it to cook a meal of bacon and eggs and run a small gasoline motor on it.


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