Storage of Methane & Hydrogen gas at home

What I have done to catch methane in a pig_plant long ago is:

I took a 44gal (200l) steel drum and removed the top. The drum is placed upside down over and in the production juice. with guides rails to keep it upright. the air is removed. The methane (lighter than air) will fill the drum and lift it. the outlet pipe was fixed at a high point. I had a petrol/paraffin engine changed to run on the Methane.

I suppose the same trick will work for H and O.

The Hydrogen and Oxygen will develop at a specific electrode. Space apart sufficiently.

Were doing this on a slightly larger scale ( 50 ft x 14 ft ) but I've seen your type set up here in America and abroad. Their very effective machines and I never saw one implode, that was if you first purge the 1st gas produced, so you will be down to just the Methane & no air/oxgen. H2 is a bit finer, but perhaps.

What about the flow or flash arresters & pressure valves; what did you use ?

Thanks

Joe In N GA

Oh yes , just what is a petrol/paraffin engine ?

Thanks

Joe In N GA

It has 2 tanks (smaller for the petrol) You start it on petrol but switch over to paraffin once it is warmed up properly.

I am talking about 40+ years ago. detail is becoming blured. The setup was used to charge 32volt Edison batteries. for general lighting. The biggest solar sell known at that stage (too me in any case) was the one used in a camera light meter.

We used a control valve borrowed from an acetylene bottle.

And 1 after thought: In this case, H2 is a splitting of water and as such the Ox/air will constantly re-appear from the splitting. You just can't purge it like in Methane production as that's in a air free area. With H2, You gotta seperate it as you produce it.

Thanks

Joe In N GA

Methane storage is simple: any recipient that can resist the pressure and the residual acids will do the job.

The H2 is much more difficult: it is not needed to have a hole to let the H₂ escape: even the tightest metal Christal structure has openings larger than H₂ atoms: up to 4% of your recipient content will simply merge through the wall.

The energetic content of H₂ by volume is also very low. You will need a large tank to have some energy available. These two counterfeits of H₂ are the big no go's for H₂ cars.

It is wiser to connect your PV cells to batteries and to charge a battery bank. Way less trouble and known technology.

Or skip the PV idea and focus on the methane production, with the right bacteria you will be able to ferment extra stuff from other sources.

Processing the raw methane can be done with a Stirling engine: he can easily burn these gasses as it is an external burn system. IC engines can't handle the other stuff that you will find in the methane.

You might try a company called "United Nuclear"

www.unitednuclear.com

Cool Site.

You may want to look at this guys technology for scrubbing syngas into pure methane. www.binair.ca

Good luck!

To store the methane, you will first want to clean it up. This will require water absorption canister and a CO2 absorption canister. If you chose to compress the gas and have lots of room, the propane tanks should work well, even though they won't hold as much as the propane as it is stored as a liquid. The easier way to store methane is as methanol which is a liquid at room temperature. You should be able to find a catalytic converter to add the oxygen atom. The best solution is to burn the gas as you generate it.

How do you isolate the flow in 1 direction might be another really good question to ask also ?

Buy, don't bother making, a check valve, this will allow flow of gas in only one direction.

I agree with the previous comment that it is better just to store surplus electricity in batteries as there are inefficiencies in electrolysis of water.

Hi SDA1950 ,

Clean up of raw gas before storage seems like sound advice and we had considered compression at a later point. Start with inexpensive tanks as we have several and can add more easily. The burning of all CR4 at production, is just not possible as production would be larger than a small sized fuel generator requires and you kinda have to stay ahead of the game with digestion and CR4 production

When you say "liquid storage" how do you mean that ?

And "a catalytic converter to add the Oxygen atom" are you referring to use as a ICE fuel ? The CH4 would be free of O. at its creation and storage and the intake of a ICE would provide needed Oxygen for internal combustion as with gasoline usage ; Would it not ?

If steam reformation - to turn a turbine was the motors power force - then perhaps you might need a ventilation system to feed the burners but, thats about all I am imagining in my ignorance .

Thanks for your comments.

Joe In N GA

The burning of all CR4 at production

This could make the CR4 people nervous!

The liquid to which I'm referring is methanol (CH3OH) which is just methane (CH4) with an oxygen added to one of the hydrogen atoms. It is a liquid at room temperature and atmospheric pressure which is my suggestion for your storage issues. It could be burned in an ICE, but it emits some nasty chemicals (at least it does when mixed with gasoline). Any other combustion engine would be fine, sterling, steam, ... or even fuel cell.

If taking up room with propane tanks really isn't a problem, then a simple pump will solve that problem without a catalytic converter. You just have to be aware that the tank is only good to about 400 psi, please check as that is just an estimate, and methane unlike propane is still a gas and hence much less dense at that pressure.

Steve

According to this presentation 65% efficiency is about all you can expect for H2 production via electrolysis. With 12% efficient solar cells, this would then be 7.8% overall efficiency. If the H2 is then used to run an engine, to generate electricity, then the engine will operate with perhaps 25% efficiency, and the generator will operate with about 85%. So you would end up with electricity generated with an overall efficiency of 1.65%. However, if this H2 is stored for long, perhaps 1/3 of it will leak through the container walls, so overall efficiency may be closer to 1%.

If you charged batteries, you'd get about 90% efficiency. Inverters are about 95% efficient, so you'd get AC current with about 85.5% efficiency. This, times the original 12% efficiency of the cells, would give a system efficiency of about 10.3%. So you'd get around ten times as much work out of your solar cells.

I noticed you mentioned (as did another respnder) that H2 cant be stored very long because it penetrates through the walls of the metal container. How is H2 normally stored then? Must it be in a condensed state?

You just accept the leakage. There is not much else to do.

Generally most h2 was produced as byproducts of refining or chemical production.

Since h2 is fairly scarry stuff, producers would just burn it off for safety.

This discussion points out some of the problems of h2 as a energy storage medium.

hydrogen is no solution for fossile fuel dependance [replacement].

liquid hydrocarbons are hard to beat, the energy density is very high.

Here is the tricky part: H₂ is not stored in large volumes and driven along.

You can buy H₂, but only in small volumes and to be used immediately, but it is rare.

Chemical processors who need H2 in their plant make it while it is needed. You can buy the generators in different sizes.

Billions of Euros have already been spend to find solutions for this problem and they are not further than prototypes of systems that show that there are other methods, but not realistic (H₂ can be absorbed by metals in large volumes, but the problem arises in the way to get it out (heating up the metal to temps above 350°C) and the absorption rate as it takes hours for a normal tank volume to be absorbed under high pressure, once absorbed the gas stays in the metal and is only released at very low rate)

BMW has an H2/gasoline car on the market in very small numbers. In nine days, its H2 tank (liquid) goes from 1/2 full to empty. Imagine you had this car sitting in your garage for a week, while you were on vacation. Would you press the button on the garage door opener? (Actually, it's not all that bad, because the vented gas goes through a catalyst, creating water vapor -- but would I stake my life on there being no other leaks?)

If H2 is stored in metal hydrides, it doesn't leak out. But when you want it out, it has to be driven out with heat, which uses energy, which drives efficiency down. (Although maybe this could be done with waste heat alone.)

Another possibility is to to make synfuel from H2 and CO2. You could run a diesel on the synfuel, and the process would be carbon neutral.

But ordinarily, I think H2 leakage is just accepted. That is one reason it has not seen much use as a fuel.

Do metal hydrides burn in the air? If so, they could be a coal replacement for a steam boiler. When the flame goes out, scoop out the metal, put in fresh metal hydride and re-ignite. I don't know much about the chemistry of metal hydrides, so I don't know of any hazards.

Steve

Yes they can burn in air. It depends on the type of hydride: some are endothermic as the hydrogen is absorbed into the metal, others are exothermic as the hydrogen is being absorbed. Hydrides are used with an oxidizer for tracers on projectiles. I don't know if they are routinely burned in air or not, and I don't know about the hazards either. Seems to make sense as a coal replacement -- although perhaps at a staggering cost, relative to that of coal. I suppose it would make sense to use the hydrogen as a gas to fuel the boiler, leaving the hydride in tanks, and recharging the tanks.

Ovonics has been working on tanks using metal hydrides. They are very heavy, with a 2.7 kg tank (about the energy equivalent of 2.7 gallons of gasoline) being over 400 pounds. But 2.7 kg of hydrogen is substantially more energy than could be contained in 400 lbs of batteries: about 10 times as much as lead acid, 5 times as much as Lithium Ion. (On the other hand, the electricity coming out of a battery is ready to use at 90% efficiency, whereas a fuel cell is a little over half as efficient.)

Hi Ken,

I will assume your numbers to be correct but after you have topped off the batterys and the building power demands are at nil what would you do with the extra solar power ? Sell it for nothing to the grid seems stupid and dumping loads into water heating when you have a perfectly fine solar water heater seems wasteful leaves one with the production of H2 as about all that is left to do with it in the daytime .

It can be used later if you tank it , perhaps metal hydride ( if I spelled that right ) would be better but, there are lots of propane tanks in the GA Farmers Market News every other week; they are pretty cheap - compaired to newer products.

Thanks

Joe in N Ga

I will assume your numbers to be correct but after you have topped off the batterys and the building power demands are at nil what would you do with the extra solar power ?

I think I would size the battery bank to be able to store the peak anticipated energy quantity. A larger battery bank would allow for discharge cycles that are relatively less deep, prolonging battery life. If these batteries never come up to a full charge in ordinary usage, an equalizing charge every few months would prevent sulfation. (You might need to run a diesel or buy power off the grid to do that -- but that is a relatively small price to pay.)

BTW re propane tanks: steel is embrittled by hydrogen, so you would want to be careful to use these at very low pressure. Unfortunately, at low pressure, it is hard to store a meaningful quantity of H2, because it is so light (less than one oz would fit in a 20 lb propane tank, at atmospheric pressure.)

I found this thread in search of a way to convert methane to a usuable gas for my home. Is there some sort of filtration system out there on a residental unit size? Can it be used year around, how is the freezing issue handled?

Leah McGregor

Methane is called natural gas in the states, so it is very usable as is, though you might want to add skunk smell to the gas as the utilities do for safety. There is no freezing issue. You will freeze to death long before the methane. The only filtration requirements should be a CO2, carbon dioxide, scrubber canister, and dehydration canister.

Steve

I asked the question because they have just put a well on our property. Part of our lease agreement is that we can get free use of any gas, oil, water they drill for. They have to provide us with access, we have to get it to our house etc. This use to be a rather common occurrance when there was a gas well on the property. Now the drilling company is trying to get out of it, telling me it will freeze, I won't be able to use it in the winter, will need to be cleaned, blah, blah. I don't think it is as complicated or expensive as they are trying to make it sound. So I thought this looked like a good place I could get a bit of education on the subject. Our acreage is so minimal the only real benifit to us was the use for our farm in signing the lease.

Leah McGregor

The filtering is to remove the sulphur deritives, which are relatively caustic to burners & pipes. Molecular sieves. Manure digesters, may have the technology you need.

Attention: what comes out of a well is something completely different from the gasses produced by a fermentation process.

You will find lots of hydrates and other stuff that will indeed freeze and clog your pipework, and of coarse the drilling company (or the owner of the well) will try to give you this nasty stuff.

Try to find a specialist on oil and gas well and let him decide where they should connect your pipe. (after the first separation stages and pressure relief)

If needed you can heat trace your pipework. Burn the gas in an adapted generator set (Stirling is perfect for the job) and use the electricity in your farm and for the tracing. The waste heat of this set could be used to heat your domestic water and house.

If they would decide to flare of the gasses try to convince them to use a closed system and get your heat from there, again stirlings could do nice thins here.

And don't mess with the gasses yourself.

I hadn't plan to try any of this myself, as I am obviously quite uneducated about it. I'm going to have to look up terminolgy just to figure out what you said in the above message. I'll talk with the company that said they could hook us up and see how they had planned to do it. This thread has been helpful I at least have some questions to ask and a direction to start in.

Thanks

Leah McGregor

Leah,

The company is lying to you.

Methane (CH₄)
16.0426 g/mole
Freezing point: -182.5 C (Per Google.com,-296.5 degrees Fahrenheit)

Boiling point: -161.5 C (Per Google.com,-258.7 degrees Fahrenheit)

HITRAN number: 6

Steve

This comes from: http://vpl.ipac.caltech.edu/spectra/ch4.htm

Oh, I'm certain they are. The owner of the company that was going to do the plumbing for me has gotten very interested in it and is talking to people and researching it. There are quite a few of these wells going in this area now and I will not be the only one that wants to utilize the gas or have that option to. I appreciate any suggestions or information I can get from here.

Leah McGregor

Does anyone know who sells those hugh digester bags ?

Iv'e seen some on you tube in use that were about 100 ft long . Then you could cut it at 50 ft and double the bag within itself.

Please do not joke or think about storing methane in bags. It's a good way to die.

Steve

There Not For Storage there for digestion.

Hi Everyone,

Here is some additional information on working gas systems.

I have included a Link to a commercial sized biogas system , much like what we will be building in GA. except that the waste from the digester will also be used and thats not shown here. The UC Davis video is the first link and that web site has several links for your viewing pleasure including a cambodian plant featured on youtube.com but its all spanish language, with text on the site for us old Gringos

Joe In N GA

UC Davis Video

http://www.ruralcostarica.com/biogas-video-uc.html

A beginners guide to biogas From University Of Adelaide that has good info & pictures.

http://www.adelaide.edu.au/biogas/

Joe In N GA

Lets keep this thread alive as its producing gas

we have recently did a project for storage of biogas. We tried to purify the biogas using regenrative chemicals like ammonia water. but the results were not very attractive. water purification method seems to be good. it not only removes CO2 but also other impurities like H2S .....

We then compressed the gas using refregerant compressor (for methane as refregerant). the compressor was of 130 watt and inlet flow rate of .4 litres per sec and capacity to copress upto 25 bar.

We used LPG cylinder (33 litres) and compressed the gas upto 10 bar storing total 443 litres of gas. and to our surprise the energy consumed by the compressor was only 1-2 % of the total energy stored in the cylinder.

Now we want to compress the gas at sufficient pressure and use it for cooking purpose. Is that possible. Is bottled CNG ever used for cooking purpose?

any suggestion ... Please help

Alok Dhunganan

Nepal