Can Solar Energy Be Used to Efficiently Produce Hydrogen from Water?

[gravenewworld]

On-Demand Hydrogen System Ready To Roll
A catalytic process that produces high-pressure H2 from liquid hydrocarbons as needed improves the prospects for using H2 as a fuel

The University of North Dakota's Energy & Environmental Research Center (EERC) has announced development of a catalytic process that produces high-pressure hydrogen gas as needed from any type of liquid hydrocarbon, improving the prospects for using H2 as a fuel. The on-demand system, covered under U.S. patent 20060225348, can be used like a regular gasoline pump to fill up fuel-cell-powered vehicles, construction machinery, and electronic equipment with H2 while it is made from natural gas, gasoline, or renewable fuels such as bioethanol or biodiesel, EERC Associate Director of Research Thomas A. Erickson notes. This approach improves hydrocarbon fuel efficiency, permits easier trapping of CO2 and pollutants during H2 production, and avoids the need for a national H2 distribution infrastructure, Erickson adds. The steam-reforming process uses commercially available catalysts to strip hydrogen from carbon and purify it, similar to steam methane reforming in oil refineries. What makes the method unique, Erickson points out, is the ability to maintain H2 at pressures up to 12,000 psi, rather than isolating H2 at ambient pressure and then compressing it before use. EERC is working with industry partners and the U.S. military to commercialize the technology.




Source: ACS

 

[Ivan Seeking]

You can't provide a link?

It doesn't say is how efficient the process may be. That is what really matters. Also note that a patent is not a scientific reference. There are plenty of bogus patents out there.

 

[russ_watters]

I don't see anything in that that implies they've done anything new. Steam reforming is not a new process and though it provides us with a bridge to a hydrogen economy, it isn't capable of sustaining one since it still requires fossil fuels.

[edit] Incidentally, copying and pasting the whole first line into google returns only this thread...

 

[Ygggdrasil]

Why is converting liquid hydrocarbons to hydrogen fuel preferential to just using the liquid hydrocarbons as fuel? Neither approach decreases our dependence on foreign oil and both approaches create carbon dioxide. Now, if the carbon dioxide could be captured and sequestered, reforming hydrocarbons at a centralized plant could, in theory, make this process emission free. Unfortunately, no good carbon capture and sequestration technologies exist yet. So, this approach solves neither of the major problems which we would like a hydrogen (or other alternative fuel) program to accomplish.

Now, I could see that the gain in efficiency from using a fuel cell could make this process more energy efficient than directly burning the hydrocarbons. However, I would guess that this gain in efficiency would be lost when you consider the energy needed to store the hydrogen (pressurizing it or liquefying it) and transport it.

Ultimately, hydrogen is just a means of storing energy, not an energy source in itself. Unless the hydrogen comes from a non-fossil fuel source (such as nuclear energy, solar, wind, etc.) it will not provide significant relief to the environmental, economic, and social problems created by fossil fuels. Thus, developing alternative energy sources to create hydrogen should be a prerequisite to widespread use of hydrogen fuels.

 

[russ_watters]

Why is converting liquid hydrocarbons to hydrogen fuel preferential to just using the liquid hydrocarbons as fuel?

The major benefit is that a fuel cell is goverend by different themodynamics than an internal combusion engine and may be able to run more efficiently.

 

[gravenewworld]

You can't provide a link?

It doesn't say is how efficient the process may be. That is what really matters. Also note that a patent is not a scientific reference. There are plenty of bogus patents out there.

It was a news blip from the American Chemical Society's weekly magazine Chemical and Engineering News. I can't link to it because you won't be able to read it unless you are a subscriber.

 

[Ivan Seeking]

It was a news blip from the American Chemical Society's weekly magazine Chemical and Engineering News. I can't link to it because you won't be able to read it unless you are a subscriber.

Yep. I saw the ACS but thought it was worth checking.

 

[Ivan Seeking]

Ultimately, hydrogen is just a means of storing energy, not an energy source in itself. Unless the hydrogen comes from a non-fossil fuel source (such as nuclear energy, solar, wind, etc.) it will not provide significant relief to the environmental, economic, and social problems created by fossil fuels. Thus, developing alternative energy sources to create hydrogen should be a prerequisite to widespread use of hydrogen fuels.

One hopeful candidate for the production of hydrogen is algae. Among others, there is a group at MIT working on this - not to be confused with algae produced biodiesel and ethanol.
https://www.physicsforums.com/showthread.php?t=211274

 

[chemisttree]

Here is the text of http://appft1.uspto.gov/netacgi/nph...8".PGNR.&OS=DN/20060225348&RS=DN/20060225348" No fee required.

Looks like SMR at much higher pressure and only slightly lower temperature.

The present invention is similar to SMR in that both processes can involve the use of natural gas as a hydrogen carrier, water as a reactant, and a catalyst to promote methane reforming to hydrogen and carbon dioxide. However, there are several distinctions between the two processes. One distinction is the temperature and pressure ranges utilized in the reforming reaction. In the present invention, the reactor is maintained within temperature and pressure ranges of approximately 375.degree.-640.degree. C. and 2000-12,000 psi, respectively. In contrast, SMR utilizes reaction temperatures and pressures ranging from about 700.degree.-1000.degree. C. and 30-735 psi, respectively. Another distinction is that the present invention can be utilized with hydrogen carriers other than natural gas/methane, including--but not limited to--propane, butane, methanol, and ethanol.

(from the patent application)

 

[Wellesley]

Hydrogen fuel is here?

Hmmm...I have a feeling that the issue of a 12,000 psi container at -640 degrees C, in a car will hamper the actual production of hydrogen fueled cars for a while.

... Ultimately, hydrogen is just a means of storing energy, not an energy source in itself. Unless the hydrogen comes from a non-fossil fuel source (such as nuclear energy, solar, wind, etc.) it will not provide significant relief to the environmental, economic, and social problems created by fossil fuels. Thus, developing alternative energy sources to create hydrogen should be a prerequisite to widespread use of hydrogen fuels.

Hydrogen can be split from water molecules although the process isn't very efficient. Since the Earth (for now) is abundant with water, some consider Hydrogen as a renewable source of energy.

 

[chemisttree]

Hmmm...I have a feeling that the issue of a 12,000 psi container at -640 degrees C, in a car will hamper the actual production of hydrogen fueled cars for a while.

True, but the point was that you had production going on at point of sale rather than a centralized plant which would require a completely new and expensive distribution system from that plant to the point of sale.

Hydrogen can be split from water molecules although the process isn't very efficient. Since the Earth (for now) is abundant with water, some consider Hydrogen as a renewable source of energy.

No one considers hydrogen in of itself a renewable source of energy. It is a way to store energy from other sources (which may include renewable ones like hydroelectric, wind and solar) only.

 

[Wellesley]

True, but the point was that you had production going on at point of sale rather than a centralized plant which would require a completely new and expensive distribution system from that plant to the point of sale.

I understand that this new method could possibly simplify the process of making hydrogen viable as a fuel. Yet, isn't moving production of hydrogen from a central factory, to an actual pumping station, analogous to extracting gasoline from crude oil at a gas station? If hydrogen were produced at a central station, it would seem as if it would be the same process currently used with gasoline production.

No one considers hydrogen in of itself a renewable source of energy. It is a way to store energy from other sources (which may include renewable ones like hydroelectric, wind and solar) only.

You are right, it isn't a renewable source per se. Although, if hydrogen were extracted from water, the source of energy (water) would remain viable for a long time. In a way, I meant that water could be considered as an abundant source of energy, even though it technically isn't renewable.

 

[TVP45]

I shouldn't think this is a breakthrough. More than 90% of US hydrogen is now made by steam reforming. Although the hydrogen is easy to use and quite clean at the point of use, it still requires much energy to make and presents us with problems (not unsolvable, but cumbersome) associated with catalysts. The US DOE has an energy information administration that puts out a lot of analysis on the economics of various energy sources, although they fail to clearly enough make the point that hydrogen is not a primary source.
http://www.eia.doe.gov/
I should point out that economics is the prime criterion since that will drive investment. Government has the ability to shift economic viabilities, but the bulk of the investments must come from the private sector.

 

[Ygggdrasil]

You are right, it isn't a renewable source per se. Although, if hydrogen were extracted from water, the source of energy (water) would remain viable for a long time. In a way, I meant that water could be considered as an abundant source of energy, even though it technically isn't renewable.

Water isn't the source of energy here. From thermodynamics, we know that you have to ADD energy to water in order to get hydrogen. Otherwise, you could not gain energy by burning hydrogen. Thus, the source of energy is the electricity you use to split the water molecules. And, since most electricity (in the US at least) comes from coal, this method of producing electricity (in addition to being fairly inefficient) is not very green and non-renewable.

One way to create hydrogen renewably would be to use algae or some other microbe to produce hydrogen (as mentioned by Ivan Seeking). In this case, the energy used to split water (or other compounds) comes from sunlight, a renewable resource. The other way would be to develop green, renewable sources of electricity for electrolysis.

 

[Wellesley]

Water isn't the source of energy here. From thermodynamics, we know that you have to ADD energy to water in order to get hydrogen. Otherwise, you could not gain energy by burning hydrogen. Thus, the source of energy is the electricity you use to split the water molecules. And, since most electricity (in the US at least) comes from coal, this method of producing electricity (in addition to being fairly inefficient) is not very green and non-renewable.

One way to create hydrogen renewably would be to use algae or some other microbe to produce hydrogen (as mentioned by Ivan Seeking). In this case, the energy used to split water (or other compounds) comes from sunlight, a renewable resource. The other way would be to develop green, renewable sources of electricity for electrolysis.

You are right. Maybe the third time's a charm: Hydrogen can be produced from water, although this process is rather inefficient. Hydrogen can also be considered as an abundant storage source of energy, but not a renewable source of energy.

Sorry about that...

 

[Ygggdrasil]

Water is a "source" of energy insomuch as a refrigerator is a source of food. With a refrigerator, you put can food in and you can take food out, but you can't take more food out that food you've put in. Even worse, with many sources of hydrogen, you have a freeloading roommate who will consume some of your food and drink. So, if you put in a six pack of beers, you might end up drinking only four of them.

 

[alxm]

You are right. Maybe the third time's a charm: Hydrogen can be produced from water, although this process is rather inefficient. Hydrogen can also be considered as an abundant storage source of energy, but not a renewable source of energy.

Well, producing hydrogen from water by ordinary electrolysis is inefficient.

There's no reason, though, why you can't produce it efficiently and directly from solar energy. If you can find the right catalyst. (preferably a cheap one) There's a lot of research going into that.

Main strategies would be organometallic catalysts (rhodium complexes iirc) and engineering an enzyme (say, combine photosystem II with a dehydrogenase, or something like that). It's all theoretically sound. Just a damn hard thing to pull off in practice.