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Post by sigurdur on Oct 27, 2016 13:25:57 GMT
I have no problems with Hydrogen. However, Hydrogen has problems with metal. It bonds with it, making it very brittle. NDSU has been working for years, trying to find a hydrogen/diesel mix that doesn't cabbage out engines. Cat is one of the sponsors for this. So far, everything goes well for about 800 hrs, and then valves break, cracks appear in the block.....etc. Ceramic seems to be the answer, but so far they haven't produced a ceramic valve/piston/ etc assmbly that can withstand the pressures over an extended run time. Maybe some day? The hope was farmers could put up wind turbines and generate their own fuel. There are a couple of things I'm thinking about as I read this, Sig. The first one is that there is more than one type of hydrogen engine. I think what you are talking about is the internal combustion hydrogen engine. It has been experimented with, and I think you're right about one of its biggest weaknesses. I'm thinking primarily about hydrogen fuel cells. That's very different. It's also possible to line the storage and delivery systems with substances that don't react so readily with hydrogen, and so metals don't touch the hydrogen, except in the internals of the power cell where metals may catylize the power-producing reactions. Am I right in understanding what you're talking about? It doesn't matter the source of the hydrogen, what matters is the interaction between the metals and the hydrogen. The unit that they developed used gas hydro produced somewhere else. North Dakota folks are rather innovative. Basin electric set up a prototype plant to produce hydrogen using wind turbines as the source of the electricity for the conversion. The idea was to store energy to drive a turbine when there was no wind. The metallurgy problems became evident in that experiment as well. Not sure if they are still searching, or have stopped the project. Storing the gas is difficult, as it leaches so easily. The turbines, as built, didn't hold up well either. The only practical use of hydrogen in a vehicle is to use a fuel cell so that production is done and used quickly. There have been advances in ceramics of late that may allow a functional long lived power train in a vehicle. Potentially, at some point that may happen for heavy equipment as well. Interest has waned as the price of diesel has declined and the economics today, and for the immediate future, indicate that the potential payback, cost/benefit ratio isn't feasible.
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Post by slh1234 on Oct 27, 2016 15:22:25 GMT
Sig, it doesn't sound like we're on the same wavelength. Let me see if I can bring it together. I wasn't implying that the source of the hydrogen makes any difference. It makes a difference in trace impurities, but they are largely inconsequential to what I was saying. What I was talking about was the difference specifically between an internal combustion hydrogen engine vs. hydrogen cell electrical production to power a car/other. "The hydrogen internal combustion engine is simply a modified version of the traditional gasoline-powered internal combustion engine." (Ref: en.wikipedia.org/wiki/Hydrogen_internal_combustion_engine_vehicle). BMW is the main auto-maker that I'm aware of that has developed a car using a hydrogen internal combustion engine. The Toyota Mirai uses the hydrogen fuel cell to produce electricity, and the electricity powers electrical motors which propel the car. A quick summarization of the fuel cell is here: en.wikipedia.org/wiki/Fuel_cellI understand you to be talking about hydrogen embrittlement: en.wikipedia.org/wiki/Hydrogen_embrittlement . Definitely this exists with many metals, although it appears that not all metals or alloys are susceptible to it. The article seems to place the main hazard of hydrogen embrittlement in the manufacturing or welding processes. I don't know for sure, but I could see a possibility for hydrogen embrittlement occurring with a hydrogen internal combustion engine, as that would seem to put hydrogen in contact with metals at a high temperature and pressure. However; I could see lining the contact surfaces with materials that are not susceptible to hydrogen embrittlement as possibly preventing or minimizing this. I have read about ceramic engines, and although I don't know for sure, that doesn't sound like a durable engine. I don't know for sure what BMW does to address hydrogen embrittlement. I see five different classifications of hydrogen storage tanks (not including metal hydride storage). I was looking to see who defines these as it doesn't appear to be ASME, with which I am most familiar. However; when you view these categories of storage tank, not all of them are metal. The vehicles I am aware of that are powered by hydrogen fuel cells use a type IV tank which does not have metal in contact with hydrogen: en.wikipedia.org/wiki/Hydrogen_tankProduction of the hydrogen is another moving part, but it doesn't necessarily need to put metal in contact with stored hydrogen. The only place I know of where electrolysis puts a metal in direct contact with hydrogen is possibly on the surface of the cathode, but even there, it would appear that it is possible to use a carbon electrode instead of a metal electrode. The process certainly isn't new, and it is done commercially for applications where CO cannot be allowed as a trace impurity since CO is a trace impurity in deriving hydrogen from hydrocarbons. I simply disagree with your assertion that the only practical use of hydrogen is where production is done and used quickly. In fact, that would make it entirely impractical since it takes energy to produce the hydrogen, and the energy is then used to produce electricity in the fuel cell. That's why I was thinking of hydrogen production via solar powered electrolysis, storage and pressurization in the (probably type IV) tanks, refueling in the type IV vehicle fuel tanks, and use in the fuel cell to power the car. I really think we have the technology pretty well established to be able to power cars. We don't have the infrastructure for it. Some applications, such as jet engines, probably will never be a good application for hydrogen fuel. Heavy equipment may not be there now, but may be in the future. Certainly, things such as warehouse forklifts could be powered with hydrogen with the current state of technology, though. Does that bring us onto the same page?
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Post by sigurdur on Oct 27, 2016 15:57:25 GMT
Yes.
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Post by icefisher on Oct 27, 2016 16:56:10 GMT
I don't know for sure what BMW does to address hydrogen embrittlement. Support for the BMW dealership repair services network?
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Post by Ratty on Oct 28, 2016 0:17:41 GMT
Interesting discussion, broadened my understanding. Thanks all.
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Post by sigurdur on Oct 29, 2016 14:40:34 GMT
theconversation.com/hydrogen-could-become-the-new-fuel-for-cooking-heres-how-66241“Too much dirt,” says Justine about the difficulties of cooking with charcoal for her household of five. She’s a mother and market trader in the town of Sogakope in south-east Ghana, and referring to the soot that is produced because charcoal doesn’t burn completely. The reason she still uses it? “Cheap,” she shrugs. Justine’s neighbour Janet is also complaining. She cooks with firewood but it produces too much smoke. It is a typical problem in a country where most cooking involves burning fuels like these. Women do most of the cooking and collect the fuel, and they are becoming more and more aware of the dangers of air pollution in the home.
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