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#21
August 12th 05, 12:22 AM
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Michael Coslo wrote: wrote: Michael Coslo wrote: What are the byproducts of converting seawater to hydrogen and oxygen? Mostly salt. And chlorine. As you mentioned in another post, sodium hydroxide. However I don't see that as a big problem. Either the electrolysis process can be made to not split the NaCl, or it can be recombined and the energy recovered. The main byproduct problem I see is that you'll have lots of salt. Hydrogen is seen as some sort of saving angel in the energy issue. Producing the hydrogen is a bit of a problem though. It takes a lot of energy to produce it. It has a pretty low volumetric energy density. Which means it is compressed and your fuel tank becomes a highpressure canister. Not only is the stuff flammable, like gasoline, but it's under high pressure. Two ways to go boom. But to the problem at hand, a somewhat practical method of producing H2 would be to electrolyze it, using Nuc power. The electrolysis plant would probably be set up near the ocean (let's not even talk of fresh water production - just ask the folks on the left coast about fresh water) So now we have an extraction plant that is powered by an unpopular power source, and has one big nasty polluting byproduct. Or we can use the other methods of generating H2. Of course, they cause as much pollution producing the fuel as if we just used the fuel in the first place. Maybe. There are all sorts of possible technologies to extract, transport and store hydrogen. For example, there's work being done to store the gas in metal hydrides. It could be extracted by using electricity made photovoltaically. Etc. The infrastructure would be interesting. The best looking way for hydride storage that I've heard of so far, is the replacement tank method. Interesting, and I suspect that teh real quick stop for fuel would become a thing of the past. Not with quick-connecting pipes. Leave it to the MEs. The big question is whether such processes can be made economically competitive. How much will a hydrogen car cost? How much will they cost to drive per mile? What are the maintenance costs? Maintenance would *probably* be improved. I suspect that engines would last longer, and be a lot cleaner to be around. Agreed! But the cost competitiveness problem still exists. The big problem is that there's probably no single magic long- term solution. Rather there are a bunch of small solutions that add up. Here's two favorites of mine: Imagine a tall (couple of hundred feet) hollow tower, in the desert. A vertical pipe, as it were, with holes around the bottom. Around its base is a large circular greenhouse whose roof slants toward the tower. When the sun is out, the air under the greenhouse roof is heated, and rises. This creates an artificial wind towards the tower. The warmed air goes up the tower, which contains a wind-driven generator. Works whether or not there is a breeze. The generator and its impeller are near ground level. Etc. Good process, and an old one. A lot of places in the middle east use those type of towers (usually lower) to bring cooling air into the house. The process also works for a limited amount of time after the sun goes down. The warm ground heats the air above it. The ground under the greenhouse roof can be farmed, if there's water available for irrigation. also There's a process called TDP (Thermal Depolymerization Process) that can supposedly break down various types of waste into fuel oil, gas and other usable products. For example, there's a pilot plant here in Philadelphia that takes sewage sludge (ugh) and breaks it down into a type of fuel oil, methane gas, water, and some other things that are usable as fertilizer. The result is also sterilized. If nothing else, it gets rid of the stuff! Which is a major problem today. Two birds, etc. Another plant in Carthage, MO, takes the waste from a turkey-processing plant and extracts oil, gas and some other products from it. The company claims that many other feedstocks can be used. Old tires, a chronic disposal problem, can allegedly be broken down into oil, gas, steel, fiberglass and carbon black. The process supposedly uses 15% of the product to run itself. hmm, not too bad... *IF* it really does what is claimed. That's the problem with a lot of new technologies: If they're for-real, the developers are very secretive about the actual process because they're afraid it will be stolen. If they're a scam, the developers are very secretive about the actual process because they're afraid it will be discovered to be a fake. Of course the above pilot plants produce fuel at the rate of a few hundred barrels a day. It's doubtful that either of the above will solve all our energy problems. It's also unclear as to whether they are economically feasible on a large scale. But if they are doable, they can sure help. In the case of TDP, a big part of the waste-disposal problem can be dealt with. 73 de Jim, N2EY |
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