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Old 09-02-2011, 15:38   #31
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the biggest problem of switching to Hydrogen is storing enough, as you can just compress it, as with propane it is liquid, but if you are making it on an ongoing basis that shouldn't be too big of an issue.
As to safety, I'd get a few hydrogen sniffers to let you know if you get a leak or look into adding an odorant,
Most fuels are burning hydrogen as hydrocarbons, CH4 is methane to make H2O X2 and CO2 when burned. The more complex the more energy per chain, but the chains are heavier and tipicly burn slower, relitively.
As to adding hydrogen to your engine, are you planning on pure H2 or browns gas? Browns gas is very dangerous to store.
With running a stove, I would recomend purging the line well before lighting, as if your fuel line has an air/hydrogen mix in it it could ignite in the line, but after it is just H2 not an issue, you will just need and adjustable regulator and different jets.
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Old 09-02-2011, 17:58   #32
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You guys are awesome!

I want to thank all of you for taking this seriously and constructively.

After reading many of the posts, it does sound very risky.

The point of the project is complete freedom from external fuel supply. I can visualize a very difficult time ahead and do not want to depend on anybody to provide my basic life sustenance. Yes, today supply is cheap and readily available! Can you count on tomorrow?

I will tinker and if I can demonstrate a viable system, I will gladly share. This summer I will try to give a report.
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Old 09-02-2011, 18:25   #33
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I think the problem with your plan to use hydrogen is that you are underestimating how much power it will take to generate even a small amount of hydrogen and how fast you will consume it. Given the efficiencies of current methods for generating hydrogen on a small scale I seriously doubt that you'll make enough to last more than a few seconds if you're burning it. For hot water you would be much better off using simple a solar thermal collector and to divert excess wind power into a resistance element. You can now buy hybrid solar panels that combine solar thermal and photovoltaic collection. The solar thermal cools the photovoltaics, making them more efficient. Even if you could compress it to 700 bar (nearly 10000 PSI) you would still need 8 times the volume of hydrogen as you would diesel. 700 Bar is way more pressure than a scuba tank can hold. At scuba pressures you would need more than 25 liters of storage capacity to equal 1 liter of diesel or 15 liters to equal 1 liter of LPG. You would need a very high tech system to compress the hydrogen from atmospheric pressure to 3000 PSI without blowing yourself up. I would question on whether you could actually do that on a small scale without using more energy to compress the gas than you have in the container. Look at the energy value of hydrogen/liter at atmospheric pressure on the graph. It's almost zero. You would need to collect the hydrogen in some sort of large balloon like bag. The fact is Hydrogen is just very inefficient form of energy storage. For cooking you would be much better off putting charging a large battery bank and cooking with a microwave. At least most of the energy goes into the food and not into heating the air in the boat. You can get 80-90% of the energy you put into a battery back out. You'll never approach that level with hydrogen as current generation methods are probably less than 50% efficient in the generation and then you have to compress it to store it. I would guess your overall efficiency will be 20% or less.
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Old 09-02-2011, 18:36   #34
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Originally Posted by TheWatchman View Post
I want to thank all of you for taking this seriously and constructively.

After reading many of the posts, it does sound very risky.

The point of the project is complete freedom from external fuel supply. I can visualize a very difficult time ahead and do not want to depend on anybody to provide my basic life sustenance. Yes, today supply is cheap and readily available! Can you count on tomorrow?

I will tinker and if I can demonstrate a viable system, I will gladly share. This summer I will try to give a report.
A few more practical thoughts:

* You need to use freshwater, not seawater. Seawater will give chlorine gas instead of H2, which is bad.

* H2 has a VERY broad range between explosive limits; that is, the range of explosive mixtures (LEL to UEL) is MUCH wider than other fuels. That combined with a high flame speed will result, I think, in a very different burner design.

* The flame is basically invisible. We've had hydrogen fires in the refinery, and even big ones are hard to spot; mostly, they're hot. Very hard to be certain when they are out. We also use hydrogen burners in the lab (long story); the ONLY way we can tell if they are lit is by placing something cold (chrome plated wrench, glass) in front of the flame and watching for condensation.

+1 on the microwave...

or burn biomass or eat cold food.
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Old 09-02-2011, 23:24   #35
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Didn't anyone read my post.

You don't need to store hydrogen, for this application, you just make it as you need it.

It is well known than aluminium and sodium hydroxide with water produce hydrogen.(lots of it)
If your source of aluminium is cheap, recycled or from discarded soft drink cans.
That is CHEAP energy.
It is relatively easy to make a gasoline engine run on hydrogen (it has been done many times.

Look we are not trying to save the planet here.
We are looking at a cheaper source of powering a boat, not cars or aircraft, simply boats.

Why can't it be done.?

Please comment on the concept i am presenting.
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Old 10-02-2011, 00:24   #36
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beau, what you describe is what my friend has in his pickup. It works.

He gets a measurable improvement in gas mileage. However the brushes in the alternator are taking a beating.

I think he is close to breaking even on the investment in parts for the mods after a couple of years effort. If the alternators survive just a little bit better it will start to pay off. He's working on dual alternators now. He's a major tinkerer just out to have fun.

He won't be able to pass by the gas pump ever though. Can't produce enough electricity in a four wheel vehicle to do that.

Gas for cooking? Hot water? Might be doable.
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Old 10-02-2011, 01:16   #37
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Four winds,
I am interested in what type of system your friend is using.
I have found that there are a number of hydrogen systems being used as a supplement to gasoline on cars, to increase milage and range and it does appear to work even on diesels.
However the commercial systems I have seen so far appear to work by using electrolisis a very inefficient method of producing hyrogen.

What i am trying to suggest is that hydrogen based systems using Aluminium and Gallium or Sodium hydroxide may help cruising boaters increase range and costs.
And it is not based on complicated technology but it may take a new(improved) practical application method, which is well suited to cruisers.
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Old 10-02-2011, 04:29   #38
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Didn't anyone read my post.

You don't need to store hydrogen, for this application, you just make it as you need it.
OK, so let's see the numbers. A single stove burner has 2kW heating power on the average, give or take some. I personally wouldn't touch the lye+aluminium H2 generation method with a long pole (too dangerous, have you ever seen the results of lye burns to skin or eyes? Not a pretty sight...), so the only remaining method is water electrolysis. And, as already mentioned, you will need pure water for that. Where will you get it on a boat and at what energy cost?

Now, the best reported energy efficiency of electrolysis I am aware of is about 60%. For the amateur setup, a figure of 50% is probably the more rational assumption, maybe even too optimistic. So, to store 2kW in Hydrogen using electrolysis, you will need to input 4kW of electric power to the tanks...

Now, this power has to come from somewhere. No fossil fuels.. So either solar cells or wind generator. I do not have efficiency numbers for wind generators handy, but good commercially available solar cells have energy efficiencies in the range of 17%. Let's assume you buy something really good (and expensive) and you get 20%... This means you need 20kW of solar irradiation to produce needed H2 'on the go'. The standard solar irradiation used for such calculations is 1kW per square meter. So, you will need 20 square meters of high efficiency solar panels just to run a single stove burner 'as you go'.

Quote:
It is well known than aluminium and sodium hydroxide with water produce hydrogen.(lots of it)
If your source of aluminium is cheap, recycled or from discarded soft drink cans.
That is CHEAP energy.
It is relatively easy to make a gasoline engine run on hydrogen (it has been done many times.

Look we are not trying to save the planet here.
We are looking at a cheaper source of powering a boat, not cars or aircraft, simply boats.

Why can't it be done.?

Please comment on the concept i am presenting.
Almost everything can be done. Whether it is practical is another story.
Have a look here: Re: What are the products of Aluminum + Sodium Hydroxide? and calculate how many grams of aluminium and sodium hydroxide are needed to run a 2kW burner for an hour should you insist on this method of producing H2. Calculate the amount of water needed too... Now estimate the needed storage space on a boat, say, for a month.
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Old 10-02-2011, 04:46   #39
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Didn't anyone read my post.

You don't need to store hydrogen, for this application, you just make it as you need it.

[...]

Why can't it be done.?

Please comment on the concept i am presenting.
OK, I posted a long answer to your question, but it seems to have disappeared (why?). Long story short, making H2 as you need it is not practical. Numbers don't lie. I estimated, that to supply hydrogen needed for a single 2kW burner using electrolysis you would need approx. 20 square meters of solar cell panels at peak insolation. Lye+Alu is IMO too dangerous (skin/eye burns possibility).
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Old 10-02-2011, 06:09   #40
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Finally Jim Cate and Bill Streep get to the real safety concern about using hydrogen, keeping the molecule contained. Plenty of the fuels and liquids already in use and stored on boats will blow you up but the risks and methods to manage them are well established.

If it leaks hydrogen is much less likely to accumulate in a boat since it is much lighter than air but less likely does not mean it can't happen in the right circumstances.

In addition to storing the hydrogen there are the issues with production and the current energy (in)efficiencies or dangers with the processes.

However the potential environmental benefits with using a pollution free (depending of course on generation from water with green energy) and renewable fuel should be strong motivators to solve the technical and safety problems.
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Old 10-02-2011, 06:23   #41
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joshua slocum boiled his alarm clock in vinager,to make it work,so he could get an accrate fix,i wouldn't do that with a gps the size of a wrist watch,or any gps.

but funny thing is at the end of the day the equipment achieves the same thing,a position.

their is light at the end of the tunnel but at the moment we are boiling the alarm clock..........
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Old 10-02-2011, 06:33   #42
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Making enough Hydrogen to do the job in a limited space is a real challenge. As has been pointed out by the other posts. 1. more volatile than other flammable gasses, 2. leaks readily, (you dont realize the difference until you use it, we use hydrogen to find leaks in stainless steel vacuum fittings, it will seep through 1/2 inch of stainless steel). 3. expensive to make 4. difficult to store in any quantity, low energy per volume. 5. Flame is invisible, actually burns in ultraviolet. 6. Burns hot, difficult to control.

If you could make a special stove that took aluminum and caustic soda that generated the gas right under the burners, that migh work except I don't think the reaction would make the gas at a steady enough rate to power the burner. Once the flame goes out, (its invisible remember), you would quickly have an explosive situation. Hydorgen explodes in almost any concentration.
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Old 10-02-2011, 06:43   #43
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A hydrogen generator to produce a hydrogen flame will of course work. They are used for some types of small precision welding work. Please note that the generator will produce both hydrogen and oxygen, and these must be kept separate for safety (at least until used), or in your case discard the oxygen. If not then you will have both the fuel and the oxidizer premixed in perfect proportion (ka-boom).

The real issue is efficency. You lose energy turning electricity into hydrogen and oxygen, lose again throwing away the oxygen and lose again turning the hydrogen back to water. It would be more efficent to use the electricity to heat an electric burner directly.
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Old 10-02-2011, 06:44   #44
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...
It is well known than aluminium and sodium hydroxide with water produce hydrogen.(lots of it)
The explosion of aluminum dust and H2 will be seen a hundred miles away!

One problem I see with your method is that the reaction is hard to stop if it gets out of control (I'd venture that most school lab fires are related to that experiment). Your friend may park the truck on the shoulder and watch the fire from afar. In a boat you don't have that privilege.

I think is great to play around with the idea. But I wouldn't put that thing in a boat together with my family.
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Old 10-02-2011, 06:49   #45
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TheWatchman:

When you pull into the anchorage, drop your hook and fire up your hydrogen fired stove, how about flying a special burgee flag- one with a bomb symbol, so we can all know to move.

Seriously, hydrogen is 1000 times more likely to leak than propane. And if a leak catches fire (and it is very likely to do so, sometimes just from the static electricity generated) it burns with an almost invisible flame.

Good for rocket fuel however.

David
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