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Topic: Hydrogen economy  (Read 22973 times)

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Offline Borek

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Re: Hydrogen economy
« Reply #15 on: November 04, 2006, 07:32:00 PM »
1. Hydrogen is flammable, but by the time it has caught fire it will be high in the air.

Have you seen Hindenburg crash?

Quote
2. There are more advantages to hydrogen than there are disadvantages.

Where did you get that opinion?
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Offline Donaldson Tan

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Re: Hydrogen economy
« Reply #16 on: December 08, 2006, 04:57:54 PM »
I would like to bounce an idea arround. Last spring for a graduate project, I took up the challenge of producing hydrogen with low energies. I looked at biotechnology as an answer. I proposed a method of identifying enzyme catalysts based on protein structures obtained from RCSB.ORG.

Are you involved with this research?

Scientists have combined two molecules that occur naturally in blood to engineer a molecular complex that uses solar energy to produce hydrogen gas from water, says research published today in the Journal of the American Chemical Society.

This molecular complex can use energy from the sun to create hydrogen gas, providing an alternative to electrolysis, the method typically used to split water into its constituent parts. The breakthrough may pave the way for the development of novel ways of creating hydrogen gas for use as fuel in the future.

Professors Tsuchida and Komatsu from Waseda University, Japan, in collaboration with Imperial College London, synthesised a large molecular complex from albumin, a protein molecule that is found at high levels in blood serum, and porphyrin, a molecule which is used to carry oxygen around the body and gives blood its deep red colour. Porphyrin molecules are normally found combined with metals, and in their natural state in the blood they have an iron atom at their centre. The scientists modified the porphyrin molecule to swap the iron for a zinc atom in the middle, which completely changed the chemistry and characteristics of the molecule.

This modified porphyrin molecule was then combined with albumin; with the albumin molecule itself being modified by genetic engineering to enhance the efficiency of the process. The resulting molecular complex was proven to be sensitive to light, and can capture light energy in a way that allows hydrogen gas to be produced from water molecules.

Dr Stephen Curry New Window, a structural biologist from Imperial College London's Division of Cell and Molecular Biology who participated in the research explains: "This work has shown that it is possible to manipulate molecules and proteins that occur naturally in the human body by changing one small detail of their make-up, such as the type of metal at the heart of a porphyrin molecule, as we did in this study.

"It's very exciting to prove that we can use these biological structures as a conduit to harness solar energy to produce hydrogen gas from water. In the long term, these synthetic molecules may provide a more environmentally friendly way of producing hydrogen gas, which can be used as a 'green' fuel."

Journal Article: "Photosensitised reduction of water to hydrogen using human serum albumin complexed with zinc protoporphyrin IX", Journal of the American Chemical Society
« Last Edit: December 08, 2006, 05:33:31 PM by geodome »
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Offline P-man

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Re: Hydrogen economy
« Reply #17 on: December 20, 2006, 06:07:22 PM »
1. Hydrogen is flammable, but by the time it has caught fire it will be high in the air.

Have you seen Hindenburg crash?

Quote
2. There are more advantages to hydrogen than there are disadvantages.

Where did you get that opinion?

Hindenburg... what makes you think hydrogen was the most flammable thing aboard the ship?

And all the facts point out that hydrogen, unfortunatly for oilmen, has more advantages than disadvantages.
Pierre.

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Offline Borek

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Re: Hydrogen economy
« Reply #18 on: December 20, 2006, 06:19:14 PM »
And all the facts point out that hydrogen, unfortunatly for oilmen, has more advantages than disadvantages.

As usual, you have no idea what you are talking about, but you are preaching as if you have spent all your life researching hydrogen.
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Offline constant thinker

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Re: Hydrogen economy
« Reply #19 on: December 20, 2006, 10:03:12 PM »
I can think of an advantage to hydrogen over oil from a U.S. stand point (also applies to other areas I guess).
Decreased CO2 emissions from cars, and lower pollution in large cities from cars.

Disadvantage...
It'll take A LOT of energy to liberate enough hydrogen (assuming you take the straight hydrogen into your car route).

In the U.S. a lot of our power, really the vast majority  of it, is produced from either burning coal(49.7%). Increased energy demands for the production of hydrogen equals increased demand for coal in the energy (electricity) production sector of the market. Coal releases CO2 last I checked, and isn't a clean way to produce energy. Petroleum accounts for 3% of the production of electricity. This number will probably go up dramatically if we switched from oil because oil prices would most likely plummet do to lack of demand so production of electricity through oil will go up because it will be cheap. This won't solve the oil dependency problems.

As of right now their are major hurdles to having a vastly adopted hydrogen economy. This doesn't mean we shouldn't start now, it just means we have to keep in mind other issues like storage, replacing/adding infrastructure, getting people to adopt it, rebuilding the power grid possibly, and the increased demand of electricity.

Statistic...
2,513,609 thousand metric tons of CO2 (about 2.5 X 109) were released from electricity production in 2005. This number isn't going down.
The U.S. averaged 58,977,400 gallons of gas per month in 2005. That shows how energy hungry the U.S. is.

[Edit]I added some statistics.
All of them can be found on http://www.eia.doe.gov/.
« Last Edit: December 20, 2006, 10:20:29 PM by constant thinker »
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Offline DevaDevil

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Re: Hydrogen economy
« Reply #20 on: December 21, 2006, 04:01:52 PM »
I think hydrogen as car fuel (fuel cell cars) is a great way of getting the carbon mono and -dioxide and other polluting gases as NOx, for the most part out of the city and towards less populated areas.This will reduce smog in metropoles.

However, as mentioned before storage of hydrogen is an issue. Risks are not as great, since a hydrogen flame will be hot, but burn almost vertically due to the volatileness, unlike liquid fuels that tend to spread out. Just keep the oxygen content in hydrogen storage 0 to minimize explosion risks. Leaking of course needs to be minimized because of energy loss.

The generation of hydrogen from water of whatever other proton-containing fuel can be achieved with decent efficiency (little energy loss) at least. But then like mentioned before you need real durable ways of generating these fuels and of transfering the energy to hydrogen.
Water electrolysys has about an efficiency of 60-70% I believe to have read.
Ethanol reforming is in an advanced state now, lots of research is done on catalysts to maximize efficiency. A nice review article can be found here for ppl who have access to ACS journals.
For those who cannot: Energy Fuels, 19 (5), 2098 -2106, 2005

We'll have to see what it will be. Lots of advantages with hydrogen, but still some big disadvantages to overcome

Remember, hydrogen is only an energy carrier, not a basic energy source. The search for altenative energy is related to the hydrogen economy but hydrogen alone will not be a new energy source.

Offline constant thinker

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Re: Hydrogen economy
« Reply #21 on: December 21, 2006, 08:33:33 PM »
Hmmm 60-70%. I thought it was worse. Yea, I referring to splitting water for hydrogen. When it comes to ethanol, we talked about it as a possible alternative fuel once, and with some interesting math we figured out that we may not be able to produce enough ethanol to satisfy energy demands.

I personally am thinking that nuclear power will grow significantly (in the U.S. at least) in the next 10-15 years. No matter what, we (the world this time) will need to start moving towards other fuels that aren't petroleum based.

My post before was just trying to illustrate that as of right now, hydrogen won't solve are problems. It's a technology that in my opinion is in its infancy. Until it matures more it won't be feasible on the macro scale.
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Offline Yggdrasil

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Re: Hydrogen economy
« Reply #22 on: December 22, 2006, 12:30:59 AM »
I think I remember reading that the efficiency of electrolysis (at normal temperatures), is close to 40-50%.  The efficiency is higher when the electrolysis is performed at higher temperatures (e.g. using the heat radiated from nuclear power plants), however.

I agree that hydrogen can eventually become the major fuel in our society, but there need to be major scientific breakthroughs before this technology will work and we need to develop a "green" source of electricity to power hydrogen production.  Whether these developments come in time for hydrogen to replace gasoline before global oil prices begin to skyrocket and greenhouse gas emissions get out of hand is questionable.

Offline billnotgatez

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Re: Hydrogen economy
« Reply #23 on: December 22, 2006, 11:15:01 PM »
Quote
Hindenburg... what makes you think hydrogen was the most flammable thing aboard the ship?

The Hindenburg burned in 34 seconds, which would not have happened if it were filled with helium.

Quote
Risks are not as great, since a hydrogen flame will be hot, but burn almost vertically due to the volatileness, unlike liquid fuels that tend to spread out.

The hydrogen energy lobby says this just to promote their cause, but they are biased in their assessment.



Offline Donaldson Tan

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Re: Hydrogen economy
« Reply #24 on: December 23, 2006, 12:44:31 AM »
What's wrong with exploding about 150 liters of hydrogen... only 0.01 millihindenburgs by my calculations...
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

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