Author Topic: Solar Generated Hydrogen  (Read 654 times)

dieselspanner

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Re: Solar Generated Hydrogen
« Reply #15 on: August 14, 2018, 06:01:26 PM »
You don't have to muck about with chemistry to get a good fuel air explosion, the US was at it in the late '60's, dropping a ton of propane at a time.

Look up the Pave Pat BLU 72 bomb..........

Cheers Stef
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mike90045

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Re: Solar Generated Hydrogen
« Reply #16 on: August 14, 2018, 06:28:41 PM »
The awesome thing about a baggie of hydrogen with a whiff of air, is the explosion is so very closely coupled to Air, it's quite efficient at transmitting the shock wave,  no nasty steel casing or sawdust to get in the way

glort

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Re: Solar Generated Hydrogen
« Reply #17 on: August 26, 2018, 08:33:42 AM »

My Dodgy hydrogen genny has been working reasonably well of late. I have been getting a conservative 50L of gas per day.  Probably more.
I was up the shed today and heard an unusual sound outside.  Went round and realised it came from where the gas genny was. had a look and touched the lid and was greeted with another hydrogen burp. I didn't bleed it yesterday so it was over full in the 110L capture drum.

Seems to be doing well and I'd like to use it but after the detonation the other day, don't mind admitting I'm gun shy.
I did remember I have a couple of flashback arrestors in the garage somewhere on my oxy Acetylene torch. I no longer use that due to the extortionate price of gas and bottle rental now.

I might look at putting one arrestor at the torch and another at the source and give it a go. Far as I can tell they should stop a hydrogen backfire but if they don't and 110L of the stuff goes off, I'll probably never know anyway.

People reckon I have big balls and take risks with 600Kw oil burners but the guys playing with that HHO gas are on another lever of either crazy or ignorant from where i'm standing.
Even just Hydrogen with that range of volatility limits scares me.  Putting the oxidiesr in with the gas..... Death wish.

I'm no wondering with the amount of gas I'm getting how much it really is? If I'm getting 50L day, how much gas would I need say to boil an average kettle  or cook dinner?
Any smart person out there able to do a calculation of the amount of energy in KW in a Litre of Hydrogen so I can put it in terms in my head I understand what I'm getting out of this? 

EdDee

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Re: Solar Generated Hydrogen
« Reply #18 on: August 26, 2018, 09:22:35 AM »
Hey Glort...

Rumor has it that the standard flashback arrestors don't work too well... Best I have used is a 'bubble type' arrestor... basically a bubble trap in the line, the inlet feeding into about 6 in below the water surface and bubbling up to the surface... any backflash and it forces a water column into the feed pipe, creates a plug and isolates the flame front from the storage side... easy to make and reliable too...

Way safer than those deathly oil burners with difficultly flammable fuels...

Cheers
Ed
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ajaffa1

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Re: Solar Generated Hydrogen
« Reply #19 on: August 26, 2018, 01:03:25 PM »
Hey Glort, please stop playing with this sh1t. I have seen the aftermath of a underground mine explosion
(methane). What kills the miners is the gas they have inhaled exploding in their chests, it`s not pretty.

If you want to go down the hydrogen route please approach a reputable and experienced specialist. You could probably convert a browns gas (plasma style) cutter to feed a bench top gas cooker but it would probably bugg*r all your wife`s cooking pans. If you got a leak it would blow the roof off your home and kill all inside.

Bob

glort

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Re: Solar Generated Hydrogen
« Reply #20 on: August 26, 2018, 01:42:36 PM »

I can't see myself doing much with it Bob. It was really just a rush of blood to the head when talking about excess solar and storing it.

I'm not afraid of gas in the slightest. I think it's pretty docile really but I love the way people are ship scared of it and the disillusion they have about it.  I think the hissing noise scares them.  I would happily feed it into an engine from a hose, make burners which I have done and more but this stuff has an uncertainty about it I don't like.

I had an idea that  normal flash back arrestors didn't work  either and while I knew about Bubblers, I was looking for something a little more proven and of industrial reliance and certainty.  Without something like that, I'd be too scared to light this stuff or use it. Call me Chicken and maybe it's my ignorance about it but I just have no confidence in it.  I know enough about gas to know what I can and can't do, same with oil. Like petrol, in my book at least atm, hydrogen is too risky for me. I thought I did know  about it and didn't think thee was much problem with a concentrated gas but my little plastic bag explosion and the realisation of how little air you need in the stuff to make a big  problem was an eye opener.

I think I might have a go at Poo gas when the weather warms up a bit. If I can make that work I could extend the production life with an insulated and solar electric heated tank.

I'LL have to get a Balloon this week and see if the Hydrogen is good for making Floaty Amusements.

If nothing else this bit of playing around was good for giving me some  knowledge and insight into something I never had before.
back to the search for a PRACTICAL way to store excess solar power.  If I find that, I'll be Hosting the first all expenses paid LEF convention for everyone here so we can all meet up. 



ajaffa1

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Re: Solar Generated Hydrogen
« Reply #21 on: August 26, 2018, 02:12:02 PM »
Hey Glort, so glad you have decide that and early and unpleasant death is not for you.

There are some hydrogen fuel cell vehicles come onto the market soon. Perhaps we should be looking to buy the first ones that get wrecked and use the innards to power our homes.

Poo gas or biogas are doable but require too much biological matter to be practical in a small setup.

Floaty amusements sound like great fun but please remember that the recent Sydney train outages were caused by Helium filled kids balloons landing on the overhead conductors causing them to short out. I dread to think what would have happened if they were hydrogen filled.

Bob

glort

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Re: Solar Generated Hydrogen
« Reply #22 on: August 26, 2018, 02:58:01 PM »
Floaty amusements sound like great fun but please remember that the recent Sydney train outages were caused by Helium filled kids balloons landing on the overhead conductors causing them to short out. I dread to think what would have happened if they were hydrogen filled.


I hadn't heard that but I looked it up.
What a complete and utter load of Horse Hockey!  A little thin foil type balloon " Short Circuited" a power line that runs at 1500V at a few thousand amps?
Was the balloon 2.5 Cm thick or what?  What a ridiculous load of crap to insult peoples intelligence with!

If a balloon had made contact with that amount of current it would have been vaporised with a few hundred amps if that and it wouldn't have even made a blip in the system.  How the fk can a balloon " Short" out a power line capable of supplying the power a train uses? In order to short it out the load would have had to be many times more than the train consumes.

Man they sure treat people like morons.  How the hell did a balloon make contact with the rail and the over head line 6m above it at the same time?

If it were filled with Hydrogen it may have made a pop but being that there is no containment of the pressure or shrapnel, it probably wouldn't have even knocked the bird droppings off the wires.

I wonder what REALLY happened they are trying to cover up?  Probably a major failure or some 14 yo kid hacked the rail network server and changed all the time tables or just shut it all dawn. Clearly something  they really didn't want to admit was the real cause!

The Biogas feedstock material wouldn't be an issue.  Horses and cows around here everywhere and places regularly advertise giving it away.  I can go down tot he sale yards just down the road and they will load my ute and trailer with as much as I want.  Might go down there this week actually.
Need some fertiliser and dressing for the lawns and garden.

I might start off with a batch of poop gas and see how I go from there. If it works OK i'll put some effort into making a system I can recharge.



BruceM

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Re: Solar Generated Hydrogen
« Reply #23 on: August 26, 2018, 04:35:29 PM »
1Kg of Hydrogen is equivalent to 1 US gallon of gas.  Sounds good so far since much better energy density by weight. Alas, at room temperature and 1 atmosphere (no) pressure, that's 12 cubic meters or 12,000 liters of hydrogen gas. 

If you pressurized it to say 150 psi (a nice pressure for a 2 stage air compressor) or roughly 10 atmospheres, you need a pressure vessel of 1.2 cubic meters (or 1200 liters) for every 1 gallon of gas equivalent of hydrogen.  A 1000 gallon or 3800 liter propane tank is about $3000 US or $2000 for a used tank.  Filled with hydrogen at 150 psi that would hold the equivalent of 3.2 gallons of gasoline, energy-wise.   So if you want to store up the equivalent of a couple hundred gallons of gasoline for winter heating, for example, you'd need 63, 1000 gallon tanks.  Obviously, you might want to bump up the pressure as high as your tanks would allow to reduce that number or store a bit more fuel.  If using new 1000 gallon propane tanks, that's $190K in tanks to store the hydrogen equivalent of 200 gallons of gas.

To store the equivalent of a 10 gallon gas tank (automotive) at 150psi you need a 12000 liter pressure vessel in the car, or a trailer with about three 1000 gallon propane tanks. Not very practical.

Commercially they use high pressure tanks, but they suffer from hydrogen embrittlement and must be replaced regularly.  Out of sight for the DIY'er.

Thus the interest in lithium hydride for gas storage instead of a big hydrogen tank farm. It allows a lot more gas to be stored at modest pressure in a much smaller tank.  It's still very expensive and not in common use. 

A synthetic gas derived from hydrogen which can be liquid at reasonable pressures comparable to LNG (synthetic methane) may be more practical.










mike90045

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Re: Solar Generated Hydrogen
« Reply #24 on: August 27, 2018, 01:36:22 AM »
Your storage tank of pure hydrogen, will not burn or explode.  But if you get >4% of air into it (not sure if that's air or O2) a backflash will make a big boom.  Pure, it does nothing, because there's nothing to combine with

glort

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Re: Solar Generated Hydrogen
« Reply #25 on: August 27, 2018, 02:44:18 AM »
  But if you get >4% of air into it (not sure if that's air or O2) a backflash will make a big boom. 

And therein to me lies the problem.  That's not much air and would mean to me that everything would be best evacuated before you tried storing the stuff.

Also if somehow my production is off and there was a bit of oxygen to mix in with the Hydrogen......
Buying a bottle of the stuff commercially would not worry me because I know it would be tested and up to standards.  I'm doing backyard hackery here so I need a much wider margin of error in order to be comfortable with things.

I was naive to what you have pointed out with the low air ratio and the wide explosive levels. I thought I was being safe and clever going for pure hydrogen and avoiding the hohoho gas but that little plastic bag explosion was a wake up call. From the bit of hohoho gas I have played with in the past, there wasn't that much difference in the results for the volume.

A big difference in what I want to do and what otehrs do is I'm trying to generate the stuff over time and store it. Most others are generating large amounts on the fly and using it straight off.  If they have a pop it's going to be like 2L. I'm storing and feeding from over 100L.  One is a loud bang and a bit of flying plastic, the other is well into bomb level results.
I wasn't looking at this to make gas, I was looking at it as a way to store energy for later use.  It does not meet my objectives with a level of safety ( and geez I loathe to use that word!) that I am happy with. I might do this fine for years but the potential of a brain fade of which I am highly prone are catastrophic.  the potential benifit of saving a few bucks on my already much lowered power bills..... Lets just say I'm a wimp and rather pay the extra.
If I ever do decide to leave this earth by my own choosing, it will be exactly that, by my own choosing and in one piece, not by some unexpected mishap that potentially causes parts of me to be gathered from various parts of the yard and maybe some never found!.

I'm sure there are ways to make it safe and use it but it's beyond my confidence and level of manliness  not to mention technical accuracy.  I'm certainly not the sharpest tool in the shed but I can recognise this stuff is out of my league so may be i'm just smart enough where i need to be.  :0)

Bruce,
You were getting noticeable by your absence mate.  Glad to see you are Ok.
That is some VERY interesting info.  I learned a lot just reading your post.  As you know I'm interested in the future energy sources especially for transportation and that really puts a whole new light on it.  I had no idea hydrogen was so light on energy density.
As I read your Post and saw you mention 1Kg of Hydrogen I thought a KG in an uncompressed gas which hydrogen typically is, is going to be a lot of gas. you went on to confirm it was a lot more than I'd have ever given credit for!

12K Litres of uncompressed gas to get less energy than stored in a mower fuel can which here is typically 5 litres.  Incredible.
If I transfer that into things I am more familiar with, Veg oil, 12 IBC's of veg has a LOT of energy and veg has lower energy than Diesel.  I could run the heating AND Cooling for a power hungry place like mine and the vehicle for a year, at least on that much oil/ energy.
With Hydrogen, it would literally not be enough to Mow my lawn.  I use about double that in the mower and the lawn has never been properly grown since I got here!

Mate I did Biodiesel with and I have for many years marveled at the amount of energy stored in Liquid fuels and tried to point it out to others.
A few years ago at a get together I organised for the oily interested we were trying to explain to them that it would take 4 LARGE car, probably truck size batteries to hold the same amount of energy  that the coke cans they were holding would  store in oil or that one of the generators a guy had bought would need to run flat out for an hour to supply the same amount of energy the mid size burner I had brought with me could do in about 30 sec on the same 375  Ml.  That was a wake up call for a few of them.

It makes me wonder how they are ever going to get meaningful range and power out of Hydrogen cars.  Sure you can pressurise the gas but there is big energy input to that right there.  Also the safety aspect.  Having LPG as tens of thousands of Taxis use here in a tank at 150 PSI or less is a big difference to having a tank at many hundreds of PSI.  I have read they are doing tanks from carbon fibre.  Makes them much lighter than steel for the same pressure and volume rating.  Mate works in carbon fibre and the thing he has been working on for years is to try and make it less brittle. It's strong but when it lets go, it does not bend or break as much as it turns to dust.
A tank at many hundred PSI being hit and ruptured would be like a small explosion in itself without any deflagration.  Given what I have learned about the wide burn rates of Hydrogen...... You sure would want to hope it never went off or tens of people could be potentially killed from an otherwise minor accident.

I know Honda are going down the Hydrogen track more over then electric for the reasons of refueling speed and avoidance of things like dependence on Lithium and Cobalt  but there is a whole range of problems to overcome no matter which way you go.

I'd say getting the Hydrogen or a derivative to liquid form is going to be almost essential.

For all it's drawbacks, Fossil/ liquid fuels really are the ideal form of energy for transportation at the very least. 

mike90045

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Re: Solar Generated Hydrogen
« Reply #26 on: August 27, 2018, 05:21:58 AM »
Cryogenic liquid hydrogen is the only dense version of hydrogen, unless you mix with carbon to make - -
diesel fuel (hydrocarbon fuel)


You could use hydrogen to purge your containers, just process  one day, vent the next, and your container will be pretty cleaned out.