Author Topic: Solar Generated Hydrogen  (Read 655 times)

glort

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Solar Generated Hydrogen
« on: August 04, 2018, 01:52:51 PM »


Because I haven't got enough half finished projects to apply to my minimal motivation, I have started another one. A hydrogen Generator.
Was touched on in a discussion earlier but I have put it into practice. I made a small scale one and tested the gas a bit and as pure Hydrogen, it's not much different to LPG. The browns/ HOHOHO gas is completely different and in my mind dangerous but I am only using the Hydrogen with this and the Oxy is going off to enhance the atmosphere.

ATM I have an over supply of Solar power on my main array and have to apply a Dump load to avoid over voltage.Tthought it was mainly due to trying to pump too much power down the wiring but that didn't quite add up as it went voltage high well under what the cable  is rated at and what I pulled through it with no unusul voltage drop.
In reading up on this I'm finding it's quite a widespread problem due to the lazy arse power Co's not maintaining their equipment right and having a very wide variation on power standards.  Although the standard is 230, up to 253 at the point of use is acceptable yet the standards now limit inverters to 255.
Good way to stop people being too self sufficient and not paying enough to the power co's.

Instead of sinking this power into boiling water just for the hell of it, I want to turn it into Hydrogen and store it potentially to use on a stove at night.
Efficiency is not that important because anything I get is better than the 100% loss I have right now.

My gas generator seems a bit unique.  Not seen anything like it on the net.  I got a 240L plastic blue drum and cut the top off. Got a 110L dum and cut the bottom off. Fitted a Ball valve in the top and sealed it absolutely air/ gastight.  Seems way bigger than anything else I have seen on the net.
On the outside of the small floating Drum I put a steel plate about 20x30Cm. This is the Anode that generates the oxygen that is released.
On the inside of the drum I put a same size plate as the cathode to generate the Hydrogen.

Put about 100L of water in the big drum and mixed in  maybe 300G of KOH.  Opened the valve in the top, sank the drum about 60% Depth. Didn't add more water because I can't find my bag of KOH again so I didn't want to dilute the water too much.
Connected the contraption to the 2 broken panels on the roof which still work fine and it made gas.  And that's where the questions start.

It's not making near the gas I -expected- but I don't know if my expectations are realistic.  Don't know how much gas, not sure, rough guess, 10 L day. Maybe less, no real way to measure.

 Observations:

The 2 panels were feeding in around 19V -22V @ 4 XX amps.  General measurement was 130W

I hooked up the 3 Kw array which was open circuit 340V. That fell all the way to about 30V and gave about 200W over all.  The voltage/ power drop really surprised me because in the inverter it was producing about 900W at the time.  Yeah I know about the lower voltage and all that but 300 odd to 30?
Maybe the electrolyte does need thinning to let the Voltage come up and the panels get more on their curve.

Today I got a 30A 3 Phase rectifier and hooked that up to a pwm. Then things really got confusing.
AC going in was 250V. DC coming out open circuit  was around 300.... which didn't seem to add up.  Thought meter was on the Fritz but 2 More meters read the same. Put that down to no cap and the pulsing in the output.
Connected to the electroliser and again Voltage plummeted to around 15V DC.  My Meter was reading 16A @ 247V on the AC side ( which it sure as hell wasn't pulling)  but only 336W  dc which again didn't make sense.  Pretty sure the amps were right, the wire on the DC side was smoking hot after a few min and the unsunk rectifier was getting well up on temp too.  The AC voltage on the Rectifier after the PWM was down to 19-20V which again didn't make sense.  When I took the load off, was back to 250.

Now some questions that I would think were basic but I can't find answers too.....

In production, what matters, the surface area of the plates or the amps you pump through the thing?  My surface are isn't huge but I am getting the amps in there so would more plates do anything but make the " Resistance" larger?

Adding KOH will also increase the amount of amps that can be pumped in but do I need surface area for the gas to form on or is it reliant on the energy input?

Do I need equal plate area? If I put one plate on the oxy side and 10 on the hydrogen side, is it the same as If I had one on both sides or will more plates make more hydrogen gas?

I measured the output of the 2 Panels and got a bit over 6A. I measured the amps when connected to the plates and got 4.7 so I concluded the electrolyte and plate area is reasonable.  I could increase the plate area x 3 with no problem if it's going to make a difference.


I wasn't very impressed by rectifying the AC, thought I'd have a boiling cauldron but the bubbles I'm seeing on the oxy side are pretty Piddling. I did wind the power up to a KW but still nothing to write home about and nothing like the boiling I'm seeing on some YT vids but then I see they are pumping 5Kw into their generators to get that.  Ideally, I want to be able to dump about 750W. Not sure if putting a cap across the DC will help With the output.
Do I need Polarized caps for that or will  normal motor Run caps suffice?

Tomorrow I was thinking to get a DPDT and wire it so normally the power is going straight to the inverter. When the Voltage monitor is engaged, One array will send the DC to the gas generator so the power drops but is put to use.

I -could- be doing better than I thought. Before I have bubbled the gas into water to get a visual indication of production. This time I'm just catching it in a floating  drum in a bigger drum. Maybe I need to weight the floating drum down and connect a tube and bubble the hydrogen in water and get an idea that way?

I left the gas machine on a battery charger tonight and it was measuring 36W on the AC side so I'll see how much gas I have tomorrow.
Atm, I can't see this generating enough gas to cook a meal at night even if it is fed 5-700W for a number of hours.  Maybe I need a lot more plates or electrolyte but I'm thinking what matters is the amps more than anything. Is this right or am I missing something?

Perhaps my excess power would be better heating an element to keep a Bio/ Gobar gas drum up to temp and I'd get more usable Fuel that way?


ajaffa1

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Re: Solar Generated Hydrogen
« Reply #1 on: August 06, 2018, 09:38:13 AM »
Hey Buddy, I played with hydrogen production about ten years back, You are right to separate the two gases, as combined they are very dangerous. It is possible to significantly reduce that danger by thinning the mixture with regular air. there is a company that makes and sells gas cutting equipment that runs on Browns gas produced on demand.

I would advise against too high a current as this causes the electrolyte to heat up and could cause it to boil. Much better to go for lots of small cells rather than one great big one. What material are you using for your anode and cathode? Steel will very quickly corrode and contaminate your electrolyte causing the current draw to increase, with no increase in gas production. I tried various grades of stainless steel but hit the same problem. Platinum is used in commercial production but the cost is prohibitive.

I tried and had some success using the carbon cores out of used zinc acid batteries.

Bob

glort

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Re: Solar Generated Hydrogen
« Reply #2 on: August 06, 2018, 12:39:07 PM »

Hi Bob,

I am using mild steel plates atm As I got a stack of them just for the job and I wasn't really worried if I had to replace them even every month.
Didn't know about the increase in resistance for nothing.

the reason I made the thing out of a 240L Drum was in part because of cooling. I made small cells before out of PVC pipe for generator load banks and they worked just like a kettle and boiled the water.  Figured I couldn't sink enough into this to boil the water but Now I read having the water hot is a good thing.

I Burped it today into a plastic bag and maybe got 20L of gas over 2 days, today being pretty Cloudy. I was hoping for much more than that.
Not sure where I am going wrong atm. Maybe just a lack of amps?

Looking on the net I am frustrated by the HOHOHO  browns gas looneys as they tend to be all crapping on about " Extra Gas Mileage" and thinking that is the same is Hydrogen. I suppose the principal is the same for generation but it's annoying looking for info on hydrogen and practical use and Info only to always get these same crackpots and the sheeple that can't think for themselves and believe every ridiculous word.

What the hell is it with Indians that post endless comments on YT about how much is every damn silly thing on there??

Maybe I should do a debunking Vid.  Of course if I did that there would be the usual nuttters all saying I did it wrong no matter how I did it.
may as well just have an electric motor coupled to a generator and make power that way as plenty are stupid enough to believe and defend that too.

BruceM

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Re: Solar Generated Hydrogen
« Reply #3 on: August 06, 2018, 06:46:26 PM »
Regarding your hydrogen generator; you have a few things which seem to contradict convention for successful generators.  First, with only two plates, and no neutrals between them, anything over 2 volts is just heating the water.  If you look into dry cell hydrogen generators, you'll see that they are much safer, and better ones will generate about 0.5 liters per minute of separated hydrogen at around 240 watts (12V, 20 amps). The big advantage of the "dry" design is that plate connections are dry- there is no chance of a corroded electrical connection causing an explosion of the Brown's gas.  The addition of neutral (not electrically connected) plates between anode and cathode allows division of the applied voltage so that only 2 volts per gap exists; any overvoltage just heats.  For more gas production, more surface area is needed.

Reversing polarity in an iron or SS plate design will allegedly blow off the crude from the anode, extend life of the plate assembly and restore gas production rate.  Rust build up on the Anode apparently slows gas production , but dry designs from the 1930-1940's did use iron plates. 

For efficiency, current leakage from the plate edges through the electrolyte is a big factor.  This is a big plus for the dry cell designs also. 

It's a pity that hydrogen doesn't turn to liquid at a reasonable pressure.  It makes storage an expensive proposition unless you have access to large numbers of large propane storage tanks (and the room to place them) at bargain prices.


« Last Edit: August 06, 2018, 09:37:48 PM by BruceM »

glort

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Re: Solar Generated Hydrogen
« Reply #4 on: August 07, 2018, 02:50:18 PM »

Thanks Bruce.
I was wondering if there was a voltage/ amperage equation.
The problem is however, how do I turn power from the panels at around 30V @ 8A to  2V@ a lot more A?

Didn't really want to go to the trouble of building a dry/ compact generator.  Looks involved and that accuracy would be needed in drilling and mounting the plates and that sort of accuracy is not my forte.

If I have a fixed Current/ Voltage, does having more plates/ Surface area make a difference or is the amount of gas generated related to the energy invested rather than the total surface area?

Could you explain more about the plate edges? My entire plates are submerged so the edges are just more surface area in what I have.

Things to do around the place for Daughter's return party this weekend so all projects are on hold till next week but I might throw a car alt on an engine and feed the thing some serious amps to see if it does react like the other small units I built as far as gas generation goes.
I still think My " Dipped aluminium" idea has merit where there is an amount of ally suspended insie the floating drum. as the gas and the floater drop, the ally goes into the solution and makes gas. when the drum rises and pulls the ally out the water, gas stops.

Could be useful to ensure a minimum level of gas and boost the electric production.
Only thing is, it does not make use of the excess energy I want to store.

BruceM

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Re: Solar Generated Hydrogen
« Reply #5 on: August 07, 2018, 04:15:06 PM »
The gas generated is proportional to surface area and current.  The plate material does affect production rate, as does the concentration (conductivity) of of the salt solution.  Plate material affects production rate primarily due to oxidization at the anode which reduces effective plate area.  Gold, platinum, titanium or graphene coated copper are lovely but not very practical for the DIY'er.  There is a problem with highly toxic chromium oxides (hexavalent chromium) that makes stainless steel of at least some grades a very serious health issue.  Solution salt concentration improves conductivity and can increase production but also increases corrosion and decreases plate life.

Any voltage above 2V is just wasted in heat.  If your volts must be 30V, then 17 plates total will give you 2 volts per plate.  8A will do it, just not at the max possible rate.  The "neutral" or not electrically connected plates between the outside, electrically connected plates will divide the voltage down for you, and one side will be anode and the other cathode, always anode facing cathode, starting at one connected end.  The alternative is to use a Buck converter to convert to a lower voltage at correspondingly higher amps.  You might be able to find a bargain converter that fits the input range of voltages from your panel.

The plates should be relatively close to each other or you're wasting energy heating the conductive solution.  Heating is NOT helpful, as it puts water vapor with the gasses.  The edges of the plates allow current leakage through the solution which is not producing gas and just heats the solution.  Think of it as trying to only allow current a straight path from face of anode to cathode. Even sealing the edges with a coating or rubber band is credibly reported to help reduce heating.   

It is tough finding good practical info on hydrolysis because of the vast amount of garbage.

An anode tube within a cathode tube eliminates the edge issue, but plates seem easier and you aren't concerned with efficiency so much anyway.  Coating the plate edge plus a band inward with acrylic is reported to noticeably improve efficiency/reduce heating.

Refrigeration compressors can do 500 psi, and so can propane tanks.  At those modest pressures hydrogen embrittlement of the steel tank is not a serious issue. The volume of tanks required is going to be quite large since the hydrogen will remain as a gas.  I wonder what your winter gas volume requirement would be to do all your space heating via hydrogen, and how big of a tank farm that would be!

I had similar ideas to yours regarding an on-demand self regulating submersion of scrap aluminum in lye bath as a hydrogen generator.  A design challenge for something simple and effective because of the corrosive nature of the lye, and the heat generated in the process which melts thermoset plastics.  If both heat and gas can be used, it becomes even more appealing.  The inherent energy stored in aluminum is enormous.








glort

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Re: Solar Generated Hydrogen
« Reply #6 on: August 08, 2018, 12:50:11 AM »

I think you are right Bruce, There are a LOT of things that contradict setup for successful generator.

The plates are spaced about 20-30 Cm away. One is on the inside of the drum and the other on the out and opposite side.  I did it this way to keep the gasses seperated.  I could move the plates together on the same side of the drum and add more plates using  Nylon bolts so they don't contact and put oxy in the hydrogen.  Probably more trouble than I want to go to or what the exercise is worth.
Never mind, something tried, something learned.

The tank requirement for heating I think would be substantial. My goal in mind was enough gas to cook an evening meal but clearly that's going to take some investment in power and setup alone.  I might go back and give the bio gas another go seeing we are coming up to summer.  The tanks are pretty much what I need even if the inner and outer have a bit much gap but anyway.  Plenty of manure available round here for batch test processes.

Really does illustrate the real world difficulties with solar energy storage and hydrogen energy storage.
I have been reading up on on commercial systems to use excess solar  for making hydrogen and I can see why the generators are so expensive and hard to make practical.  The trend seems to be in  fuel cells but still, low efficiency and setting these things up  to power cars and houses is a very different matter to a table top experiment in a lab.

Also seeing the difficulties with solar.
It's most abundant when you need the energy least and hardest to generate when you need the energy most.

All they need to do is come up with cells that work on dark and cold ( anti energy) and the world will be set !   :laugh:

BruceM

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Re: Solar Generated Hydrogen
« Reply #7 on: August 08, 2018, 01:58:35 AM »
The poor efficiency and high cost of durable hydrolysis of water is the Achilles heel of solar hydrogen. That and the high cost of the lithium hydride for more compact storage.  We regularly spend billions on weapons and bomb development but funding for cleaner energy research is at the token level.

Woodsmoke from controlled burns and wildfires is bad here now, I haven't been able to open up at night for 4 days and it's 81F this afternoon in my house. (95F was the high.) I sorely wish I had built a water chilling system for cooling my small house already.  Brown air and heat have me struggling, health wise.





glort

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Re: Solar Generated Hydrogen
« Reply #8 on: August 08, 2018, 04:21:33 AM »
but funding for cleaner energy research is at the token level..

I think it always will be till oil truly starts running out and the cost goes beyond average affordability making profits drop.
While ever oil can meet demand, I believe competition to it will always be a token gesture appeasement of the population and another money spinner promising what is known from the start to be non viable initiatives.



I hope you are OK and not suffering too much Bruce. Give it 4 months and we will probably have the same here. The whole state ( and beyond ) he been declared Drought affected which means everything is tinder dry. Add to that the frosts we have had whech have been the most severe in a long time and all the vegetation that has killed, I think we are in for a Burning summer ourselves. 
Of course they always say it's the worst it's been for years even though the temps have been cool and not a fire around but this year, one can see clearly for themselves that the ingredients are there for bad fires.

We get some amazing smoke created sunrises and sunsets here. When we have a big fire we send smoke and ash to NZ.
Literally!

I remember a few years ago where we were getting up one morning and the back yard was a combination of Snow like ash and black bits of charcoal.  Roads and streets were like it too. Amazing how far it can travel.
I'm going to keep the fire pump and a 3000L tank of water ready to go at all times this year.

oldgoat

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Re: Solar Generated Hydrogen
« Reply #9 on: August 08, 2018, 01:02:34 PM »
I notice on the news today the CSIRO have developed a filter to convert ammonia to hydrogen and have been able to fit it in a car. For your next project Glort you can set up a conversion plant to turn your excess hydrogen into ammonia and start up a filling station. You have most of the necessary plant Hydrogen Nitrogen from the air one of your famous burners for the heat. You only need a dive compressor for the pressure.

glort

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Re: Solar Generated Hydrogen
« Reply #10 on: August 08, 2018, 02:12:31 PM »

Yes, I saw that too.  Really just another publicity stunt I think.
The only thing I know about ammonia is that a pelican like me should not be playing around with it for my good and everyone else in a 5 Km radius.

I was only thinking about doing another burner vid again today. I reckon my new neighbour would really love it.
Had the thought many times over the last few years to do burner vids and tried to do a few but these days I rarely feel like being funny although being my natural idiot self might just be enough to make people laugh.


glort

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Re: Solar Generated Hydrogen
« Reply #11 on: August 14, 2018, 09:53:31 AM »

I have been bleeding off the Hydrogen  from my tank every day or 2 over the last week.  For some reason the thing seems to have come good and is producing a reasonable amount of gas, i'd guess around 50l on a sunny day.

Today I thought I'd try some of the gas to make sure I was getting something flameable.
I got a small sandwich plastic bag and filled it best I could with the Hydrogen trying to keep the air out.  Put it on a nearby shelf and lit it.
I was deaf for 5 Minutes afterwards.  Felt the shock wave as it went off.

Didn't scare me, happened too qucik and wasn't unexpected BUT, does worry me.  I don't now know If I am somehow getting Oxygen in the Hydrogen which I cannot see any possible way ( but i'm far from an expert on this) or the hydrogen did mix with air in the bag..... Which I would have also thought unlikley.

When I did the Hydrogen from the aluminum, I bled that into a garbage bag and set fire to about 10L and got the expected lazy rich flame.... which was what I was expecting today not a deflagration that nearly pushed me on my backside and sounded like a gunshot in a closed room.

Bit wary of this now.  Thinking I'll get a balloon and put a (  small amount ) of gas in that and see how it goes. I may be able to keep the air out better.
Hopefully then I get a loping flame not another explosion. Not sure how to try and just burn it out a tube safely.

The experience did make me think about these guys that play with the hohoho gas.  They are either a lot braver or far more stupid than I am.
I am sure there are ways of handling this stuff but I cannot see that anything so Volatile is ever going to be reliable or even possible to call safe in the broadest term.  You can run electrical arcs through petrol and it would do a thing, you can run sparks in a bottle of LPG forever and you won't get a burp but this stuff is just looking for an excuse to detonate.

If this was just Hydrogen mixed with air, having oxygen mixed in as well is just a death wish.  I had played a little with HOHOHO before but forgotten just  what lethal stuff it is.
If hydrogen and a bit of air is this explosive, I think I'll put it down to a learning experience and move on.   It would be something for people with more skill, concentration and precision than I have.

ajaffa1

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Re: Solar Generated Hydrogen
« Reply #12 on: August 14, 2018, 12:13:30 PM »
Been there, done that, burned the tee shirt. Blew the shed windows out once. Very dangerous stuff.

I`ve often wondered if it would be possible to do electrolysis on something like WVO. This should produce much more hydrogen and much less oxygen along with a good amount of carbon dioxide which should act as burn retardant.

Many years back there was talk of a carburetor that did something similar and returned very impressive MPG figures, think it got killed off by the oil companies.

Bob

mike90045

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Re: Solar Generated Hydrogen
« Reply #13 on: August 14, 2018, 02:29:02 PM »
you only need   few % of air to make it explosive, and it has a very wide range of explosive mix.

Hydrogen possesses the NFPA 704's highest rating of 4 on the flammability scale because it is flammable when mixed even in small amounts with ordinary air; hydrogen gas and normal air can ignite at as low as 4% air due to the oxygen in the air and the simplicity and chemical properties of the reaction.


Mixtures

    "The flammability limits based on the volume percent of hydrogen in air at 14.7 psia (1 atm, 101 kPa) are 4.0 and 75.0. The flammability limits based on the volume percent of hydrogen in oxygen at 14.7 psia (1 atm, 101 kPa) are 4.0 and 94.0."
    "The limits of detonability of hydrogen in air are 18.3 to 59 percent by volume"[6]
    "Flames in and around a collection of pipes or structures can create turbulence that causes a deflagration to evolve into a detonation, even in the absence of gross confinement."

(For comparison: Deflagration limit of gasoline in air: 1.47.6%; of acetylene in air,[7] 2.5% to 82%)


The Hindenburg airship burned, it did not explode.  It's suspected that the aluminum powder paint was a major contributor to the tragedy, but it was not hydrogen exploding or burning, hydrogen flame is invisible (it burns blue in the UV range) and if it had exploded, the bystanders would be deaf.
« Last Edit: August 14, 2018, 02:32:36 PM by mike90045 »

glort

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Re: Solar Generated Hydrogen
« Reply #14 on: August 14, 2018, 03:02:04 PM »

Mixtures

    "The flammability limits based on the volume percent of hydrogen in air at 14.7 psia (1 atm, 101 kPa) are 4.0 and 75.0. The flammability limits based on the volume percent of hydrogen in oxygen at 14.7 psia (1 atm, 101 kPa) are 4.0 and 94.0."
    "The limits of detonability of hydrogen in air are 18.3 to 59 percent by volume"[6]
    "Flames in and around a collection of pipes or structures can create turbulence that causes a deflagration to evolve into a detonation, even in the absence of gross confinement."

Strooth!  they are huge margins!
I never thought to look up the flammability Limits.  That explains a lot.  I think the way that bag went off today was more of a detonation.  It certainly was cracking loud and the shockwave was certainly felt.

Clearly even pure Hydrogen demands a lot more respect than I had for it. I mistakenly was thinking it was much like LPG or other gasses where the stuff was pretty lazy in a rich mixture but his is different.

I was thinking after my hearing came back what would happen if I lit the whole Drum of this stuff off.  It would have to take the side of the shed out and I would definately at best be left with permanent damage and likely life threatening injuries if that much went off.  I reckon this was about 150Ml. If I set off the definite 80L+ that was in the drum.....

I'm loosing motivation for this stuff.  I can see the opportunity for one to blow their head off very easily. If that were to backflash into a tank of the stuff, it does not bear thinking about.
Does make me laugh though, all this concern about explosives getting into the hands of terrorists and you can do this in your back yard with drain cleaner or even common salt and water if you want.  I'm not sure if I read you can't Compress HOHOHO gas very much or it self detonates or if it were something else.  Either way, even a few PSI of this into an enclosed container could do some very serious Damage.  Might still be a low order explosive ( depends on the detonation speed) but it sure would be easy to make a lot of it for no money at all to make up for a lack of actual explosive energy.