How Practical is Hydrogen Generation?

Not being any expert in this field, it's just following common-sense to suggest that a practical breakthrough needed for this "holy grail" of a hydrogen-motor, would be a chain-reaction of electrolysing water, and re-combining hydrogen and oxygen (burning), in small repeatable portions, not by accumulating, cooling the separated gases, then burning them, and for obvious reasons. Here - small is beautiful. That is not to say it hasn't been achieved already, somewhere, but bought off to be silenced since the fifties, as the myth goes on. Yuval P Mate, Haifa, Israel

Hydrogen is hopelessly expensive and ill suited to low cost uses.

It is fine for spacecraft and other similar uses where cost is not a problem.

http://www.ballard.com/be_informed/fuel_cell_technology/how_the_technology_works

The Ballard system keeps on failing on economic grounds and it uses methanol, or methane as the source of hydrogen, so the cost of creating hydrogen from those feeds reduces the efficiency.

http://www.thenewatlantis.com/archive/15/zubrin.htm

I was watching the History channel and there was this movie on German airship that carried Hydrogen to lift the airship. While the airship looked great passenger ship in air, it suffered serious accident and was burnt with lots of flame due to hydrogen in it. Many people lost their life but some were saved as airship like balloon used to fly low. I was wondering how they could make it to fly from Germany to USA in about 80 hours. Perhaps Helium balloon ship are safe as Helium does not react to Oxygen and can not catch fire.

Airship that you are refering is (was) Hinderburg. And in those days thes use Hydrogen only becouse it was chiper then Helium, wich was in great deficency. So it was more economical to use Hydrogen insted of Helium.

Hinderburg, to make that short time acrose the Atlantic, had to have large engines to prepel it forward

Anyhove Germans knew about problems with Hydrogen, but contry was in pre war state and in a recesion. But they msut show the world that they are best in more or less evrything they build. Don't forget thet Hitler finaced airship program, And that airsips ware used in 2th World War to bombard GB

The USA also refused to sell helium to germany for some reason, probably Hitler/war related.

http://en.wikipedia.org/wiki/Hindenburg_disaster

The after accident airship were supply airships and only show models. The Hindenburg accident was also believed as sabotage and this information was suppressed.

I agree that Germans did know very fine engineering in that period but taking that to war was a serious mistake. It perhaps might have been the man made cause of disaster for the airship. Whatever may be the cause, it only shows that Hydrogen was not a good engineering for the airship and was a real danger. Knowledge takes us to risk minimization.

That is throu, but as I wrote it was economical reason to use Hydrogen instead of Helium. Germans knew how Hydrogen was, but they used it anyway.

Spliting molecule of H2O into Hydrogen and Oxgen consumes more enegy then is produced reasembling it. But thare are many industry branches that wasts enormes amount of energy in verious forms thant could be used to power prces of spliting Hydrogen and Oxgen. Consecutively it could tilt the balance the other way.

For energy, the Hydrogen may be good but danger much higher so we need different attitude and education to adopt this technology. People will find way to live with risk and by proper way to reduce the risk.

Current world attitude is love and affection with poor world and sharing technology with other and not to worry too much on how some are behind others. If people with knowledge have this attitude to look from money from those who neither have knowledge or resources then it makes them unsocial and human. Brotherhood is the key for human existence and old way of dominating over the others is history. We today talk across the entire world and share our knowledge and feelings. Our hope is in earth as good place to live and perhaps for all. When people show one kind of power, then others also find other ways to demonstrate it and make the world painful. I am not for technology for war but from good human life for all. In fact I will advocate one earth one country and all part of it. To reach to that, first we should think that we are one within smaller distance.

We all should talk about Hydrogen as possible fuel to find way to produce and use it in small business places and homes.

Not economic. The USA had the only known sources of helium in volume from their natural gas wells at that time.

The USA refused to sell as they saw Hitler for what he was.

We have liquid Helium plants but not sure where from they bring their gas. I also can see kids balloons being filled by Helium gas that lifts it. Perhaps they may be getting it as a product from Petroleum Gas resource now we have.

I'm no expert here, but, SFIK, most of the deaths in the Hindenberg disaster were of people who jumped off the gondola. Those who stayed with the airship until it landed all survived. About twice as many people died when the USS Akron (a helium-filled airship) crashed. It seems likely that the hydrogen contributed to the drama, but would not have been the initial cause of the accident or have been responsible for the death toll - other than in psychological terms, perhaps.

BTW, I believe the sabotage theory is typical of the sort of conspiracy theory that tends to surround dramatic events. Regular examination for developing weaknesses was not the norm at that time, and similarly constructed vessels (I think that is the right description) were found to have all sorts of fatigue issues when examined several years later; in addition, the enclosure for the hydrogen was prone to static generation and itself of flammable materials. If these craft had been built and inspected remotely to modern aircraft standards, I think it is probable that their successors would be flying to this day.

Fyz

The point here is that Hydrogen burns and it caused Hindenburg accident. Water layer in Hindenburg accident saved few people from burning out as they were wet and did find time to escape. Hindenburg accident was recorded as this event was to be radio-cast. As the airship collapsed, its front tip actually went up in place of going down as it was having light gas Hydrogen. That perhaps made people to jump out of fire. Those were behind were also saved even though the ship touched ground from back side and collapsed completely from back to front in a dramatic way. Event took almost few minutes and people had time ti think as out outer layer was in flame and inner layer was protected by water with no fire. Hydrogen was filled in outer cavity and it also has a water layer in the same place. I think Hindenburg was the best possible design and engineers took everything they could do to make a capsule of power. How Hindenburg accident took place is of less importance to me now but the Hindenburg accident has shown that it can happen any time and it can kill people is very important. There is very little recorded information on other accidents and Hindenburg accident is something we know as it happened from recorded pictures.

Pushing Hydrogen in public places will be seen as more accidents and more causalities. Dealing with burns is already a very difficult thing to do. It sure will bring out greater technology that may promise safety. Use and through technology era has little hope. Many people these days don't believe in building homes and live in hotels. Even though life is not permanent, the home building and putting things together that will last, will be safe to use, will be worth being impressive to look at is only from past. In India, we have too many people and good home is not possible for so many people when people are growing like worms. In many countries the value system has fallen to a very low level because they have no way to reach the resources as good citizens. In 140 countries of the world, the governments don't care for their people and civilization is yet to be seen to provide minimum standard of life to all. In India, women carry tons of head-loads each day in the form of bricks or mud only to get peanuts to eat. This is what government promises as employment. They won't teach these people to use tractors or trucks and provide them resources to live a healthy human life. Our government knows TAX, TAX and more TAX. It is so in many poor countries.

Hindenburg was a reasonable design for the time, but checks and preventative maintenance were simply not on the agenda. On the basis that flammable materials are dangerous, we should ban petrol from cars and kerosene from aircraft. Using more modern materials, I know of no insoluble bars to its use in airships. As regards power generation, here are loads of issues - the main one being that it is just one of many transfer media for energy that is generated elsewhere - so there is no basis for pretending that it is particularly carbon-friendly. The only question is one of economics - there is no doubt that, at sufficient price, hydrogen can be made as safe as existing automotive arrangements

I agree that we will learn to live with dangers and will find ways to reduce accidents. If accidents will take place then we will not know as death will come quickly. Our desire to use unlimited energy will make us unsafe and yet will provide way to live that may sound safe. Are NASA shuttles safe? Here safe is not a question but some how few success are more charming that equal number of failure and death of many. Some of the technologies will emerge just because of need and not for lots of safety. Is there anything called safe war? We still have technology that claims safety to men in the field. It is all relative and each time definition will change.

Yuvalmate,

Yes we all want the "holy grail" of free energy and perpetual motion, but only the larcenous among us claim to be developing it!

The problem is simply that it takes more energy to separate hydrogen from oxygen than we get back from their recombination. The best real hope would be that somehow, energy presently being wasted by some process could be factored into the separation part of the equation and tilt the balance the other way.

There are so many problems with hydrogen that the present hype is nothing more than a distraction for the foreseeable future from meaningful, practical things we could and should be doing now.

Regards, Greg

what about the sea and electrolysis useing wave motion and current flow as power source the energy is free

Yes, but you are falling into the classic trap of devaluing the energy. It is much more efficient to convert the wave power into electricity and feed it into the main electrical grid than to convert the wave power into electricity, use the electricity to power an electrolyser to extract hydrogen (with seawater=very, very poor efficiency I might add), then use the hydrogen gas to power some other process. Extra steps in the process all reduce the energy extraction system's overall efficiency. It's the same as burning coal in a process to make another fuel that is not as good. Your better off just burning the coal as a fuel source in these cases.

there is also a buy product and that is o2 and when combined with hydrogen in 2-1 ratio and used as fuel, which is a very efficient fuel the byproduct is water and there is no nitrates or ay other nastys produced.so no ozone depletion it's clean it's good.

Dear Andrew and dear others,

I was on the latest Michelin Bibendum Challenge that was held near Paris in 2006.

There was a forum about hydrogen as a future fuel for vehicles but all experts agreed that there is no real future for the hydrogen fuel cell as it is too expensive. first of all because of the cost of fuel cells that have been in development since a few decades that shows that the cost asymptote will stick at around 300 USD per Kilowatt. Second reason is the energy efficiency of hydrogen generation and use. Tesla Motors published a good paper about this and you can download it on http://www.teslamotors.com/media/white_papers.php?js_enabled=1

So hydrogen from electrolysis would be good business for electric power plants but not for energy consumers that use hydrogen from electrolysis (too expensive per useful kWh). The state of the art level of energy needed to generate hydrogen (in the industry of electrolysis machines) is of about 4,3 kWh per m3 of hydrogen gaz at normal pressure and 25°C.

Of course if hydrogen is generated from waste heat then the cost picture may turn out more interesting. (check patent US6862330B2 on www.freepatentsonline.com for example)

Other processes seem to exist that have high efficiencies of converting water into hydrogen but I personally have no proof yet that all the information on the internet is valid. Think for example of the Joe Cell, Professor Kanarev's electrolysis, Stanley Meyer's electrolysis, Möller's Atomic Hydrogen Generator (MAHG). Has anyone independent validated these technologies and identified the electric energy needed for the conversion? According to the claims on these technologies the hydrogen should be generated when needed..... Funny how this energetically matches with laws of nature.

Then there is the problem of safety and the problem of leakage out of tanks (small molecules go through seals more easily, even if they are "tight" : how much hydrogen have you got left if you don't use your hydrogen powered car for a month... BMW should have some answers as they have experience on the latest 7 series)

If you use PV cells there are other technologies to store and retrieve energy when needed that are quite efficient and that require smaller investments and simpler technology. Eccess electric energy can be used to pump up water in reservoirs. This is done by several hydro powerplants. One of the Markerwaard projects in the Netherlands also planned to do this with excess electric energy from windfarms.

You can also use batteries.

You can also sell to the grid and buy back when needed; I guess this requires the lowest investment (just the bi-directional counter and an inverter) and a good contract with your electricity supplier. If you buy and sell at the same price I think that is fine. Here in France EDF is buying electricity from wind farms at 8,2 cents per kWh whereas it cost about 3,2 (all cost included) to make them while the market price was at 5,4 cents per kWh some time ago. So there are examples of countries that try to promote renewable energy source through price politics. Some people or companies make business from this... (produce at 3,2 and sell at 8,2)

For small scale production selling to the grid seems the best way to me.

But if everyone does that the system does not work. Powerplants would run only on part time and cost would be higher. PV cells do not produce at night so then every one should store locally.

I hope to have given you some understanding of the basics.

By the way, what solar cells do you have? Did you lay your hands on the Grätzel cell or those from Konarka?

Interesting concept here.

http://www.acsa2000.net/hshrt/

I like the Maglev idea enormously.

Thanks

Andrew

Dear Randolph, thank you for a superb and very comprehensive answer. I didn't expect my original question to spark (sic) a discussion about the Hindenberg!

Your reply makes depressing reading for me as I had become quite excited about the possibilities. My thoughts were that the electrolysis would be a very cheap process, requiring only the capital cost of PV and a good supply of potassium hydroxide. Once you have the hydrogen, there are many ways to use it, fuel cells, infernal combustion engine etc.

Why can't the fuel cell be cheap? Manufacturing cost is irrelevant, once there is a commitment, there are ways to manufacture at low cost. Is it always the raw material cost? Why not re-value platinum? It's only expensive because we say it's expensive. Our paper money has no intrinsic value, it's only what we set it at.

If the problem is that there just simply isn't enough platinum, then that's a different matter, but I'm sure there are emerging technologies in hydrogen powered fuel cells.

I think that the fact that the likes of Toshiba are heavily investing in DMFC (direct methanol fuel cells) mean that there must be mileage in that side of the technology, also I see a big future in bio-methanol as well as bio-ethanol, but not used in a very inefficient IC engine.

Getting back to hydrogen, the safety isn't really an issue, we already use really dangerous fuels. It doesn't get much worse than petrol vapour and we cope with that. What may be a problem is the public perception that hydrogen is dangerous stuff. I'm a very keen sailor and I would far rather have hydrogen on board than the butane or propane normally used. Hydrogen doesn't hang around in the bilges waiting for a spark!

Next point, why does hydride storage have to be expensive? It is a very efficient medium, very safe but still a ridiculous price, why? My guess is, not a competitive industry yet.

In the UK, we already have a fantastic gas pipeline infrastructure, perfect for hydrogen when the natural gas runs out.

Surely, though, the best reason for using hydrogen is that it is so clean, right through the process. I'm not going to give up on it yet!

Thanks for everyone's comments so far.

Andrew

Dear GreenChoice,

How relevant is cost?

Hydroscot just left a message with a link to www.fuelcellscotland.com . On that website the target price of 500$ per kW is the target and considered better than the cost of competitors' fuel cells. Compare this with a gasoline engine that runs your car: an 80kW engine costs about 1200$ which is 15$ per kW.

Suppose you need a 50kW fuel cell for the car that you would normally drive with an 80kW gasoline engine then your fuel cell would cost 25000$. On a car that costs something like 15000$ you would increase the price by 24000$. Nobody would buy that even if it is ecological. If at the same time you see biofuels being developed at reasonable cost the CO2 issue can be solved as well with low cost, low risk, no big changes of infrastructure, and no changes of human behaviour. (you will continue to fill her up as you have always done)

So I would rather look at biofuel in conventional combustion engines or at nanomolecule based battery electric vehicles. These batteries are going through rapid developments these days.

Do not forget that you calculated energy consumption for a car built of metal that is heavy. What if we could reduce weight of car for at least 50%? How big engine would you need then?? not 80kW but only 40 Kw for same performance. And moder composites allow you to do just that. Yes they are expensive because they are not mass produced. But if they would be?? What then? And if car weight could be reduced to just 30% of todays car? We all know that we would not sacrifice performance that easily!

Lye(potassium hydroxide) dissolves glass- safer is sodium hydroxide(caustic soda)- but you can use sodium bicarbonate, hydrogen peroxide, common salt & several other including battery acid- as has been said electrolytic production is more energy consuming than repay- but what does work is hydrogen production from an exothermic reaction when aluminium is placed in the above solutions in a closed container with an outlet thru a water trap to prevent backexplosion as the H2 & O recombine in the presence of a spark(static is enough)- apart from this, I have lit the emission( Brown,s Gas), which burns with an orange tinge to the flame. Over 30 years ago, several experimenters developed water powered on demand cars using this principle- but you don,t see any driving down the street now- this is not to say that the principle is invalid, just that further development is needed, & keep it to yourself if you are successful!.

I don't know much about this subject myself, but you may be interested in the following links:

www.fuelcellscotland.com

Also Hydrenergy Power Generation Systems Ltd specialise in the development and manufacture of hydrogen based decentralised power generation systems for domestic use.

Email info@hydrenergypowersystems.com

Did you know, that Island is becoming first Hydrogen country??? Meaning that thay have enormeus geotermal energy potencial for producing Hydrogen and that they will have all thair transportation needs based od Hydrogen.

The production of hydrogen at home is fraught with danger. But using sulphuric acid and lead electrodes the acid only needs to be 5% per Vol of water the higher the current the more gas produced but heating of the solution will become a problem.

The Hindenburg disaster was not just because of hydrogen being used.

The metallic coating used to protect the cloth covering was largely to blame it had aluminium and iron oxide in a flammable lacquer, it burnt at a very high temp and the hydrogen only helped to feed a fatal fire caused by a static discharge caused by flying through thunder clouds. This is the accepted scientifically proven fact. The mooring rope was wet and made the fatal path for the discharge.

Hello BrainWave

I think you have some good idea of this Hindenburg disaster.

Let me understand this first that the "Aluminum and Iron Oxide" in presence of Hydrogen will burn. Do you have details on this? I will like to experiment with this one.

I know that Aluminum is a Rocket solid fuel. Can you talk more about it?

My 2d's worth, agreeing with brainwave: finely divided aluminium burns fiercely in air, as does the basic lacquer used for the Hindenburg - in common with many lacquers used for air-planes at the time (one of these, shellac, is still widely used for models SFIK). Paradoxically, it turns out that the iron-oxide behaves to some extent as a catalyst. The lightness of the hydrogen means that its escape will cause a draught that fans the flames, but helium will be little different in this respect. Whenever the hydrogen becomes involved in the fire, it too will burn - but the flames will rise relatively rapidly, whereas the aluminium and lacquer, being heavier than air, will fall initially until the updraught develops to take them away.

Fyz

Dear Physicist

That is quite a lot of Chemistry I ever expected from a Physicist. I will try burning Aluminum powder and will add some Iron Oxides also. Fe2O3 etc. I will then add some Hydrogen to see how it burns. I think after seeing the recorded play for that accident, I now feel like doing all this to learn a bit that you all know a lot better than me. Good.

Maybe - but then I'm only a jobbing physicist, which equates to a bit of a jack-of-all trades.

I believe these were aluminium flakes, which gives a large surface area to assist in burning. Plus, I don't know this, but I suspect the flakes may have been created directly into the lacquer, which would reduce the depth of the alumina passivation layer - which protects the surface against continuing oxidation. However, that is probably largely academic once the fire is established, because aluminium melts at 660degC, at which point the oxide layer will be disrupted.

Before you start any experiments, I assume that you know the type of precautions you need to take. You are probably familiar with the use of small amounts of finely divided magnesium in fireworks. It's worth being aware that the enthalpy of formation of alumina is rather higher than that of magnesium oxide. That is to say, once aluminium actually burns, the heat generated per unit of aluminium is somewhat greater than you'd get from magnesium.

Regards

Fyz

Dear Physicist

You said you are a working Physicist. I thought there are only working engineers. I like this new name to Physics of a Physicist who is not a Physicist and yet is a Physicist. Is you chemistry also a working chemistry?

While the chemistry of my brain is not coping up easily, I will try to put things together now.

Alumina sure does not burn and is a pretty good ceramic material used in furnace up to 2000C. You said making Alumina is a bigger firework. Hum!

Aluminum (or Aluminium) I have melted in a furnace and did not burn at 800C so let me see how I can burn it in small flakes. I was actually heating some quartz bottles placed on an Aluminum sheet that was placed in a furnace to heat up to 400C but control went wrong and there are 800C in the furnace and Aluminum sheet melted like water. To get back my bottles, I switched OFF the furnace and Aluminum solidified. However, the quartz bottles got embedded into the Aluminum and perhaps got bonded to Aluminum. Inside the quartz bottles were crystals of CaF2 and LiF. CaF2 melted and dissolved LiF. I lost both of them. I just was shocked with the chemistry of melting point of crystals, glass and metal and also how solution could dissolve other crystals at high temperature and bonding of glass to metal in one go.

I will use safe furnace so not to worry about. However, experiment will be safe, I can't predict. I have seen so many odd things in the life that I never trust theories. That is one reason to test this Hydrogen Airship Explosion theory.

I suspect that Hydrogen will need some ventilated furnace so let me put it in more safe condition.

I obviously wasn't clear: it's an aluminium firework. When aluminium reacts with oxygen it forms alumina (when it is able to do this fast enough, we call it burning). As expressed in most references, the enthalpy of alumina is the amount of energy that is released when one mol. of alumina is created by burning aluminium in oxygen. If you use aluminium saucepans, the only thing that stops them going up in flames is that the initial reaction (4.Al+3.O2->2Al2O3+heat) forms a non-porous surface coating of alumina, which dramatically slows down any further oxidation.

The least dangerous item in your experiment is probably the by product of burning hydrogen - at least once it cools down. I wouldn't be so confident about alumina dust or the hydrocarbons from burning lacquer in an environment where there is limited oxygen availability.

Reading the last sentence - I wasn't aware of any explosion, though it can happen if the particles are small enough and the surfaces not oxidised (even ordinary flour suspended in air can be quite dramatic if the mix is right). The combustion may have been initiated by electrical discharge due to tribological effects (like lightning), or even true lightning - I've no way of knowing; either would sound like an explosion.

BTW, I try to avoid chemistry - you might care to read Lord Rayleigh on the subject.

Fyz

Did someone call me?

Anyway, as part of my very varied job I work on and sign off equipment designed for use in hazardous areas (refineries, powder processing plants, etc). You really would be surprised just how dangerous fine dust particles are. In the right concentrations virtually any dust is explosive for example - aluminium, sugar, wheat, flour, the list goes on. The finer the particle size, the more powerful the potential explosion. Cement dust is the exception for some reason.

I was surprised that thermite has not been mentioned yet = Aluminium + Iron oxide = heat (and a lot of it). Up to about 2500 deg C. Takes a lot of heat to start the reaction going but when initiated this compound will go straight through just about anything. Magnesium works well to start the reaction (as does strong acid). You need to ensure that the particle size is as fine as possible. More information can be found on Wikipedia.

Oh, and aluminium dust also works well as a demolition class explosive (if you know how to set up the reaction). No, I will not tell you how.

It seems you are closer to the real issues here than I, so I'm glad I invoked your spirit. Thanks for the pointer - of course the iron oxide can provide a 'nice' concentrated source of oxygen for the aluminium reaction. That would be a great explosive if it was contained in any thickness. Fortunately, in the Hindenburg it was only a thin skin - enough to get things started very nicely. Would we merely have to melt the aluminium to get this reaction well and truly going, or does it have to be rather hotter than that?

BTW, I think that most cements are already fully oxidised, so the only available exothermic reaction is with water - and the amount of heat there is about right to raise the temperature by 100-degC. But you probably knew that.

Fyz

Welllllll, the aluminium/iron compound would have to be brought up to around 2500 deg C or more before the exothermic reaction started (which is substantially hotter than the melting point, almost the boiling point!). As for an explosive, it could be made to flash, but due to the nature of the reaction I don't believe you could get a big bang and powerful pressure wave out of it. Wikipedia has some good information on it.

Generally my job in this area is to prevent explosions.

As for the Hindenburg, close examination of the video taken seemed to show that the metalwork failed AFTER the skin burned off (deformation and structural failure due to heat) and didn't really contribute to the reaction.

As a side note we also sell special thermite charges to create equal-potential earth joints for earth mats and for earthing building rebar, etc. The thermite also contains a filler metal that melts and flows into a carbon block mold to form a permanent joint. Fun, fun stuff. In this case we use a small gun with a striker that shoots out sparks from a magnesium strip to ignite the thermite. Brand names are Cadweld and Tectoweld.

I thought I was referring to aluminium flakes which I believed to have been a filler in the lacquer - but I could easily be wrong about this. If the temperature you quote is correct under these conditions*, I don't really see how the Hindenburg fire would have initiated the thermite reaction except where the hydrogen was already contributing to the fire - unless of course the whole thing was started by an electrical discharge. No, I wouldn't expect an explosion either.

*Actually, I read the 2500+ as being the temperature produced by the Thermite reaction, not the initiation temperature.

Fyz

Its hard to say what happened and what reactions actually occurred without knowing the chemical composition of the lacquer, aluminium flake size, skin composition, temperature, etc.

Mind you watching the video of it happening is worth a thousand words.

Well, magnesium burning temp is around 2200 deg C, so its somewhere around there when using that method. I don't know exactly what temp is required as it depends on particle size, etc.

Ok Hindenburg the aluminium was in the form of metal flakes and intimately mixed both with the lacquer and powdered iron oxide. Several experiments have shown that the reation did not initiate the thermite reaction but did none the less raised the temp to over 500deg C still plenty hot enough to burn very fast. The fabric burning and falling into the hydrogen storage bags caused enough heat to cripple the frame and make the airship fold up.

Dear Brainwave

Can you draw a simple model of a cross section of this airship design? I will like to have some close idea of how it was built.

Dear all,

Here is a link to "Hydrogen Research"

NASA and American universities of Nevada and Florida work on novel methods of Hydrogen Generation. Click on link to get to the page with a lot of documents and presentations:

http://www.hydrogenresearch.org/

http://www.hydrogenresearch.org/NRM_Nov05.htm

http://www.hydrogenresearch.org/links.htm a lot of links to other websites about hydrogen.

Enjoy these links and happy Easter.

Randolph

Hello Jack of all Trades

That last thing about explosive welding sure is a very good thing to bring out here. Do you have some link to it? I will like to read it. Very interesting one.

I greatly appreciate your comments and that of Physicist. I think you both are real life engineers with lots of care to your profession. This one thing makes me take lots of interest in science and engineering and many others also can get inspired. Nice thing to discuss technology and never mind if it slightly goes this way and that way.

The fire work men are sure with greater knowledge. I now appreciate that thing. I will visit the village of Shivakashi in Tamilnadu where in each house firework devices are manufactured and they export several million dollar worth of it each year. The color they get from from quantum energies are very impressive. That all it needs is a fine powder was not so much known to me except that I knew about the solid rocket fuel which is a fine mixture of metal particles.

This discussion yielded reasonable information.

Well, its not really explosive welding its Exothermic Welded (a bit like pouring molten metal). A nice slide I found.........

http://www.atitec.com/support/tectoweld/slideshow/slide1.html

Companies producing are http://www.erico.com/products.asp?folderid=138

and http://www.tectoweld.com/

Now these joints are not formed by an explosion. For that we look at another product we deal with here. It is called an implosion compression connector. It is similar to a standard compression fitting but instead of using a set of dies and a 60 ton (force that is) tool to compress the joint onto the cable (overhead aluminium HV cables in our case), the implosion joint is fitted with a special cord of explosive charge, spirally wound over the joint. So, the customer fits cable in, stands back, detonate explosive with remote detonator, and then we have a completed joint. Very handy when trying to re-terminate overhead HV conductor when it is in position on the towers.

..."The color they get from from quantum energies are very impressive"...I was not aware that Tamilnadu was at the forefront of quantum research and development.

As always you are a joy to talk to.

Just catching up on some old posts. The Americans use thermite demolition bombs to go through concrete. I designed an up dated version were I combined Mg powder and Ammonium perchlorate they called it the MOAB. I orignaly thought of a deep penetration version. At a distance it looks just like an atomic explosion. Makes a daisey cutter look like a hand grenade. They then took up a new 5000lb version super penetrating version. Goes through 30 foot of concrete like through soft butter.

Yes they use iron oxide and aluminium powder to weld rail Thermite mix it is ignited either by oxy acetylene of magnesium ribbon. The aluminium reduces the iron oxide to pure iron it only takes a few Min's to weld a rail section. Google Thermite.

Boy, you guys really get into it. I like that, but it does make for a lot of reading. Anyway, on the subject of hydrogen airship explosions, notice that hydrogen burns upward, doesn't blow like some explosions I've seen on tv. If you're going to be in a hydrogen ship (which I'd like to do if I can solve some technical problems) be prepared to escape. Have a firewall between your cabin and the rest of the ship. Have your cabin release from the ship if you're high enough for a cabin parachute to lower you safely. Keeping the cabin would be very nice if you're over water. If you're low, the worst case scenario, you're going to have to base jump..You're chute is on you at all times, even sleeping. 50 feet or lower is probably the most dangerous; short for base, long for much else. In that case I think I would try to ride it down and hope the firewall works.

Mythbusters experimented with various mixtures approximating the doped covering of the Hindenburg. This video first shows burn testing without hydrogen present (significant), and a second test with hydrogen in the envelope.

http://dsc.discovery.com/video...&titleId=412163304

For your information : The original Hindenburg caught fire so easily because of the highly flamable laquer that was used to seal the cloth that contained the hydrogen.

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Best regards,
Joff Lu
Seniod Solar Power (Shanghai) Co.,Ltd
Factory office
3-447 HengxingRoad,Shanghai,200120 China
Tel:+86 21 29422769
Fax:+86 21 29422769-15
Mob: +86- 13611984614
E-mail: joff@seniod-solar.com
Website: www.seniod-solar.com