New catalyst for hydrogen fuel cells resists CO contamination

Jul 19, 2010 by Lin Edwards report
Image credit: Journal of the American Chemical Society

(PhysOrg.com) -- Hydrogen fuel cell vehicles promise faster refueling and the ability to travel longer distances before refueling than battery-powered cars, but they are susceptible to poisoning by carbon monoxide (CO). Now, scientists in the US and Japan have created new nanoparticles catalysts that enable hydrogen fuel cells to resist CO poisoning.

Hydrogen fuel cells use platinum electrocatalysts to combine hydrogen and to produce water and generate electricity. The problem is that the hydrogen is produced from sources such as gasoline, natural gas, or , and the process often introduces carbon monoxide into the gas. Even miniscule amounts of carbon monoxide in the hydrogen are sufficient to bind to the platinum catalysts and prevent them working. Scientists at Brookhaven National Lab in New York have recently found a platinum/ruthenium that blocks CO poisoning, but since this catalyst is extremely expensive, researchers have been seeing an alternative.

The new catalyst was developed by Professor Héctor Abruña and colleagues from Cornell University, the National Institute for Materials Science in Ibaraki, Japan, and the University of Pennsylvania. They began with the knowledge that tungsten alloys resist CO poisoning. Tungsten is not used in electrodes because it is a poor electrical conductor, so Abruña and the team added tungsten to nanoparticles of titanium dioxide, which is a good electrical conductor. The result was titanium tungsten oxide nanoparticles, which they coated with platinum to make an electrode.

The researchers tested their nanoparticles catalysts with hydrogen contaminated with two percent , and found performance was reduced by only five percent compared to 30 percent for ordinary catalysts.

Abruña said he is not sure how the new catalyst works, and much more testing is required, but he thinks a likely mechanism is that hydroxide (OH-) groups bind during the reaction to the titanium tungsten oxide near to the platinum, where they are close enough to the CO molecules to react and form CO2.

If the tests prove successful and the new catalyst can be made economically, it could spark renewed interest in using liquid fuels such as gasoline in cars to make the hydrogen required to power fuel cells. This in turn could enable fuel cells cars to have a longer range than those using gaseous hydrogen and those using gasoline conventionally.

The research paper was published in the Journal of the American Chemical Society.

Explore further: Team pioneers strategy for creating new materials

More information: Highly Stable and CO-Tolerant Pt/Ti0.7W0.3O2 Electrocatalyst for Proton-Exchange Membrane Fuel Cells, J. Am. Chem. Soc., Article ASAP, Publication Date (Web): July 12, 2010. pubs.acs.org/doi/abs/10.1021/ja102931d

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Husky
4 / 5 (4) Jul 19, 2010
let me get this straight a gasoline powered hydrogen generating fuel cell, i can imagine a reduction of emissions in advanced designs, but gasoline is not exactly the energycarrier for hydrogen to solve potential oil supply problem allthough many oil companies would love this technology to extend the use of black gold into the green age, a better carrier would be electricity in advanced batteries, electricity supplied by nuclear or renewable sources
degojoey
4 / 5 (3) Jul 19, 2010
I agree, just another way to keep Big Oil in charge of it all.. AGAIN.
Ethelred
5 / 5 (5) Jul 19, 2010
This is not just a Big Oil ploy. Hydrogen fuel cells have a storage problem. So would cells based on methane. Alcohol would not have that problem and isn't part of Big Oil.

However using tungsten and platinum in many millions of vehicles seems to have materials problems. Not enough material. Platinum isn't merely expensive. It's rare and tungsten is pretty hard to get as well.

Ethelred
Skeptic_Heretic
3.5 / 5 (2) Jul 19, 2010
Alcohol would not have that problem and isn't part of Big Oil.
Actually Big Ethanol and Big Oil are bed buddies.
Shakescene21
3.3 / 5 (3) Jul 19, 2010
Producing hydrogen from fossil fuels should not be the goal. Hydrogen should be produced from water by electrolosis, with electricity produced from solar, geothermal, nuclear, renewables, etc.

Using clean hydrogen produced with clean electricity, the hydrogen fuel cell is a direct competitor with the chemical storage battery.
El_Nose
3 / 5 (6) Jul 19, 2010
What is the issue with using hydrogen from gasoline...

It sounds like people are just upset that this version of a solution doesn't put someone out of business. Which is silly to spurn inovation becuase someone will still make money off of it.

THis sounds like a great intermediate step... but people should understand Hydrogen is reletively expensive to produce, if you seperate it from water you are putting more energy in that you are getting out. And long hydrocarbons are a great source of the stuff. So unless someone has a great idea for stroage of hydrogen - which they are working on , and safe transportation of hydrogen, which they are working on -- using gasoline minus all the additives which ups the cost, sounds like a great idea. It uses technology we are fimiliar with and leaves room for future innovation and solves the biggest concern - emmisions.

This is the second step to atrificial fossil fuels and brings ethonol back as a possible substitute. With no emmision
gunslingor1
4 / 5 (3) Jul 19, 2010
El Nose - the problem with producing hydrogen from fossil fuels is that it will be far less efficient and more polluting than just using the gas. Besides, pound for pound, electrolosis would use less energy. Electrolosis could be achieved at high temperatures in non-polluting nuclear generating stations, i.e. zero net carbon.

I think your problem with everyone else above is that they recognize that fossil fuels are holding the species back, we have no need for them anymore. Why hold on to an antiquated product that kills people and destroys the planet, especially when we have things far better in every way.

"The problem is that the hydrogen is produced from sources such as gasoline, natural gas, or ethanol, and the process often introduces carbon monoxide into the gas."
-absolutely rediculous. Anyone considering producing hydrogen from fossil fuels or by burning fossil fuels is either ignorant or a stooge for big oil.

These people are gangsters.
taka
1 / 5 (3) Jul 19, 2010
And nobody recognise that hydrogen is extremly hard to handle... If jou need green fuel jou should produce gas from solal or whatever energy and use it, will be much more practikal then using hydrogen. But untill there exist natural oil this production step is smarter to drop. What is aktually needed is fuel chell working on hydrocarbons direktly, that is soo much better then just to born them.
gunslingor1
2.7 / 5 (3) Jul 19, 2010
And nobody recognise that hydrogen is extremly hard to handle... If jou need green fuel jou should produce gas from solal or whatever energy and use it, will be much more practikal then using hydrogen. But untill there exist natural oil this production step is smarter to drop. What is aktually needed is fuel chell working on hydrocarbons direktly, that is soo much better then just to born them.


taka,

And you think gasoline is easy to handle?

Tests have occured where they intentally ignited the fuel in both a hydrogen car and a gas car. The hydrogen car ends up shooting a 4 ft flame out the back, that's all, the car still ran when refueled. The gasoline engine however, exploded.

Do your research buddy.
Javinator
3.7 / 5 (3) Jul 19, 2010
Gasoline is stored at atmospheric pressure(essentially... it would actually be vapour pressure of the gasoline/air mix in the gas tank at whatever temp the gas is at, but it's still pretty low within the gas tank).

The pressure at which hydrogen is stored depends on the amount of hydrogen you're trying to fit into the set volume that is the fuel tank. It's a pretty simple gas so it fits the ideal gas law pertty well which means its pressure increases linearly with the mass of hydrogen added to the tank.

A "4 foot flame out the back" isn't exactly as minor as you're making it seem. The direction and magnitude of this flame depends on the weakest point in the tank and the quantity of hydrogen in the tank.

Generally gas tanks don't explode because the gas/air ratio in the gas tank doesn't allow for an explosion.

I'm not saynig gasonline is safe and shouldn't be handled with care, but don't tout a highly pressurized explosive gas as any safer just because it's "green".
Skeptic_Heretic
1.3 / 5 (3) Jul 19, 2010
I'm not saynig gasonline is safe and shouldn't be handled with care, but don't tout a highly pressurized explosive gas as any safer just because it's "green".
How about we tout it as safer because it is safer?

Gasoline pools keeping the fuel in the fire. Hydrogen, being far lighter than air, escapes vertically. That creates the "4' flame" effect, but it doesn't allow for spreading explosive liquids.

Secondly, we're talking far different operating oxidation temperatures. Hydrogen diffuses much more readily, making hydrogen fumes far more difficult to combust than gasoline fumes. Couple this with the operational flame temperatures and the fact that Hydrogen cannot self oxidize and you're in a bit of a pickle if you're a gasoline proponent when it comes to safety.
CavemanDev
4.5 / 5 (2) Jul 19, 2010
The unfortunate reality is that hydrogen fuel cells currently only approach commercial viability if the hydrogen is produced from hydrocarbon sources (I believe the main process used is steam reforming of methane).

While the end goal is to produce hydrogen from clean sources, researchers still have to live in the real world. Only when electricity from alternative sources becomes cheaper than the fossil fuels we are currently using will people actually pay for that clean hydrogen.

That said, the above catalyst has significant value, both as a means of furthering fuel cell research by creating engines that don't die after a couple years, and as a means of centralizing CO2 emissions. It is a lot easier to sequester CO2 in an industrial plant than in a few thousand cars.
CavemanDev
5 / 5 (1) Jul 19, 2010
Secondly, we're talking far different operating oxidation temperatures.

This statement has no bearing on the rest of your arguement. Also, "oxidation temperature"? Do you mean ignition temperature?

Hydrogen diffuses much more readily, making hydrogen fumes far more difficult to combust than gasoline fumes.

Increased diffusion only makes combustion more difficult if you have a small amount of gas and want to disperse it easily. If you have a gas leak from a tank(large source), it makes it EASIER to ignite because the concentration gradient covers a wider area, exposing the combustible mixture (proper air/fuel mix) to a wider range of ignition sources.

Couple this with the operational flame temperatures

The fact that hydrogen has a different flame temperature (ie. the temperature of the flame) only has a bearing in certain cases (generally, the weakening of materials exposed to the flame). Not as big an issue for a vehicle that is already in flames.
Javinator
5 / 5 (3) Jul 19, 2010
Forget combustion. You have a higly pressurized vessel stored within the car. You don't need fire for an explosion. To store a useful amount of hydrogen in a car you'd need more than a couple pressurized cylinders worth of hydrogen and those things pack quite a punch when you knock the regulator off.

Just as there are specific instances where gasoline is dangerous (ie. the pooling of fuel under a stationary car that catches fire), there are instances where hydrogen would be dangerous as well. Hydrogen at high pressures does not "escape vertically". It escapes in whatever the direction the hole is in and then, after the gas slows down, will rise. A 4 foot flame pointed at a passenger would finish them off pretty quick.

I'm not a gasoline proponent, but saying hydrogen is safer or easier to handle than gasoline is just incorrect.
CavemanDev
5 / 5 (2) Jul 19, 2010
and the fact that Hydrogen cannot self oxidize


Gasoline cannot self-oxidize under normal circumstances. It needs an oxidizing agent. Just like hydrogen.

Also, you keep using the word "operational". Could you explain what you mean by that?
H2Wins
not rated yet Jul 19, 2010
Compressed hydrogen as a storage medium for vehicles will be obsolete in a few years when liquid hydrogen hydrides become commercially available. These hydrides are contained at ambient temperature and non-pressurized. They have a characteristic similar to kerosene and are transported and dispensed the same way that diesel is dealt with today. Lawrence Weisdorn
jerryd
not rated yet Jul 19, 2010


Fuelcells or Foolcells as those who really know call them, are expensive, short lived and not eff despite what they tell you. A regular ICE is more eff than a fuelcell by the time all the losses are added up.

Gunslinger, Email me again if you want. I didn't see your email from last yr until yesterday. Didn't know they had emails!!
PPihkala
not rated yet Jul 20, 2010
If we have electricity made from whatever source, best use for it is to charge a battery with it and then use that battery to move a vehicle by discharging it through an electric motor. That process has the least losses. Using electricity to make hydrogen and then to use that hydrogen to move a vehicle is just plain stupid. If our primary energy happens to be hydrocarbons, like oil, then it still probably is wisest to burn that oil locally and use that to make electricity and heat in combined cycle. And then again to use that electricity to move those vehicles. As a bonus we get the rest heat and because it's big plant that is not moving, it's far easier to do what ever flue gas cleaning one wants. At least compared to 1000's of cars burning those hydrocarbons as gasoline or diesel, and then trying to clean after them. Just count how much 1000's of catalytic converters do cost. And every gasoline car has one. So bring me my electric car already. For EL vs ICE, goto www.teslamotors.com
gunslingor1
not rated yet Jul 20, 2010
"While the end goal is to produce hydrogen from clean sources, researchers still have to live in the real world. Only when electricity from alternative sources becomes cheaper than the fossil fuels we are currently using will people actually pay for that clean hydrogen."
-Nuclear is far cheaper and more profitable than fossil fuels, even with the over regulation. You only refuel every two years.

Forget fuel cells, they are still a ways away, how about the hydrogen internal combustion engine. They have been manufactured. Add hybrid technology and heat recovery and you've outperformed gasoline engines in every way.

The tests are conclusion, hydrogen is in fact safer than gasoline. Do the research, though it is hard to find.. it has been supressed...but cannot be ignored.
Javinator
5 / 5 (1) Jul 20, 2010
The tests are conclusion, hydrogen is in fact safer than gasoline. Do the research, though it is hard to find.. it has been supressed...but cannot be ignored.


Luckily you provided me with a link to help.

Anyways, it basically boils down to the fact that you have an explosive gas in a pressurized tank.

Hydrogen is safer than gas in certain circumstances? Sure.

Hydrogen is more dangerous than gas in certain circumstances? Sure.

Is gasoline safe? Of course not.

Is compressed hydrogen gas safe? Not a chance.

Unfortunately we're not there with chemical storage yet since the hydrogen equivalents that are "safe" are generally difficult or require expensive catalysts to extract the hydrogen from and the hydrogen equivalents that readily release hydrogen are pretty damn dangerous.

I definitley believe chemical storage is the way to go for future hydrogen storage. We've just got to find the right way (ie. stumble on some nice cheap catalyst or something).
gunslingor1
not rated yet Jul 20, 2010
Javinator,

There are already alternative safer designs than a bottle of compressed hydrogen, things that far outpace the safety of gas.

For example, one such design puts a special type of sponge in the hydrogen storage device. hydrogen is still pressurized, but it is prevented from escaping faster than it is supposed to by the sponge. Also, when this vessel catches fire, it burns very slowly as each pocket in the spong it ignited. Guess who owns the patten to this now- Exxon.

Sorry again about sources.. it's very hard to find once big oil gets their hands on the patents... just burried.
Javinator
5 / 5 (2) Jul 20, 2010
Gunslingor,

From a quick google search (since that's where I'm assuming you're getting most of this information), the only stuff I could find about hydrogen "sponges" was on metal hydrides.

Metal hydrides are pretty common and are used in chemistry labs all the time.

Metal hydrides are quite expensive and generally quite violently with water to evolve hydrogen gas. Usually explosively so.

I'm not saying hydrogen is bad or that it's not the way of the future, but it's not "safe". It just isn't. As with any fuel it has to be handled carefully.

Just because the accident scenarios and mechanisms aren't the same for gasoline are different doesn't make it safer.

The "tests" you are referring to sound pretty biased or made up. I could do a test where you splash water on gasoline and splash water on a metal hydride and we'll see which one explodes. Would that mean gas is safer? Not at all. It just means you can splash water on it.

Fast is they're both dangerous.
gunslingor1
not rated yet Jul 20, 2010
Javinator,

I agree, every energy source will have it's dangers. Even hydroelectric, dams can collapse; even wind, HURRICANE!

I'm not arguing that hydrogen is as safe as water budy. But if safety is your primary concern, as many people with kids, then you can be rest assured that hydrogen CAN be SAFER than any gasoline engine implementation.

Reread the post, I was responding to taka who said "And nobody recognise that hydrogen is extremly hard to handle..."; I was correcting his ignorant brain who, like lots of others, failed to recognize that gas is also hard to handle so his is a moot point. Your response was a defense for him. H and gas are both volatile, obviously.

No, I was not refering to hydrides. It is quite litterally a sponge where you squeze out hyroden..the only perpose is to encapsulate and separate H storage so it burns very controlably. Like house insulation.

I agree with JerryD. Either H combustion w/ hybrid and heat recovery or electric are most viable.
Javinator
not rated yet Jul 20, 2010
I'm not arguing that hydrogen is as safe as water budy. But if safety is your primary concern, as many people with kids, then you can be rest assured that hydrogen CAN be SAFER than any gasoline engine implementation.


Car gas tanks are designed how they are because it's a cheap way to mass produce gas tanks and still have them safe enough to pass safety codes. There are likely safer designs and patents for gas tanks that exist compared to those found in the cars on the road today, but since they would be more expensive to make and automakers have no need for them, they are not used.

Theoretically, these patented hydrogen storage ideas could be safer than the current gas tanks in cars, but whether they are ever actually used in hydrogen powered vehicles when they are mass produced is a different story. It will depend on safety codes, cost, public pressures (ie. if the public is scared of hydrogen, then the tank design will be marketable. People aren't scared of gas.)
gunslingor1
not rated yet Jul 20, 2010
I agree, everything depends on design... a gas tanks haven't changed in years.. yes there are safer versions.

None of this is my concern..

My concern is when people scream how dangerous hydrogen is, yet ignore the dangers of gasoline.

I am an engineer, systems should be designed appropriately. Tests have occured. I found a restatement of the tests (good luck finding the video, though I have seen it many years ago):
http://www.enerli..._206.htm

Rebuttal or concession?
Javinator
5 / 5 (1) Jul 20, 2010
Definitely rebuttal ;)

My concern is when people scream how dangerous hydrogen is, yet ignore the dangers of gasoline.


I'm not doing this. I'm saying they're both fuels and they're both dangerous. Which of the two is safer is completely dependant on circumstance.

I read the article you gave. It's pretty vague about the conditions of the test.

http://www.unusua...tion.pdf is a much better source of information.

For gasoline the fuel line is punctured directly in the middle of the car and is ignited from directly below the car.

For the hydrogen fuel tank, it is assumed that the tank will fail at the pressure release device (likely a rupture disk).

I see a touch of bias where the gas leak is assumed to develop in probably the worst possible place for a gas leak on a car whereas the hydrogen leak develops in a designed location... CONTINUED
Javinator
5 / 5 (1) Jul 20, 2010
CONTINUED...such that the apparent 15-20 foot (not 4 foot) flame is pointed away from the rest of the car.

The hydrogen fuel tanks are designed to be much safer than those for gasoline (a point I mentioned in my previous post). It would be interesting to see what the experiment would be like if the gasoline tank were equipped with similar safety features or if say the hydrogen leak developed at the bottom of the tank as opposed to the top.

Regardless, the test was basically a comparison of apples and oranges and does not definitely show that hydrogen as a fuel is safer than gasoline as a fuel. I could likely design a biased experiment in which a hydrogen filled car explodes but it wouldn't prove anything other than that hydrogen is explosive is certain conditions.

My concern is when people scream how dangerous hydrogen is, yet ignore the dangers of gasoline.


My concern is when people see the benefits of a green technology and ignore the potential safety hazards.
Skeptic_Heretic
not rated yet Jul 20, 2010
I see a touch of bias where the gas leak is assumed to develop in probably the worst possible place for a gas leak on a car whereas the hydrogen leak develops in a designed location... CONTINUED
I think the reason for that would be that the corrosive powers of mother nature typically attack metal fuel lines before they attack plastic piping. Every car I worked on when I was younger leaked in just about the same spot, right where the fuel lines followed up the frame rail into the fuel filter area. Now whether that's due to stress from changing the filter or it's just a natural weak point I can only guess. Now that is anecdotal, but I'm tlaking somewhere in the area of a few thousand cars, all varying makes and models. It is still only as useful as an anecdote for evidencial purposes.
gunslingor1
not rated yet Jul 20, 2010
Skeptic, thanks, I learn something new everyday.

Javinator, I agree, we are talking apples and oranges. The comparison of which is safer is rediculous, that is why it is not my concern. I was only humoring taka because he was implying that gas is somehow safer than hydrogen. The only test ever conducted on the matter shows that hydrogen is in fact safer. Show me one that says gas is safer.

This is a rediculous discussion, we both agree there are dangers with both fuels, advantages and disadvantages. But if someone, anyone, ever tries to make a claim that one is safer than the other.. it would have to be hydrogen because no test have proven otherwise while 1 test has proven that hydrogen is safer.

But I agree. they are both explosive for god sakes. Trust me I'm not ignoring this.
Javinator
not rated yet Jul 20, 2010
That's fair enough for reasoning for leak location development SH.

I still feel that's more a comparison in design of the cars/fuel tanks/fuel injection system as opposed to comparison in the safety of the fuels.

I wonder what it would cost to design cars with better safety systems. I feel like the safety features described on the hydrogen fuel tank from that article could be applied to common gas tanks.
gunslingor1
not rated yet Jul 20, 2010
Those systems weren't safety systems, they are integral to the functioning of the vehicle, minus one.

Javinator
not rated yet Jul 20, 2010
"They include sensors for hydrogen that activate shut-off solenoids
in the hydrogen tank, and computer programming to shut off fuel supply if fuel flow exceeds that
used by the fuel cell, or fuel flow delivered drops by a predetermined amount."

These are what I'm referring to.
El_Nose
4 / 5 (2) Jul 20, 2010
@gunslingor1 -- and the people that voted this guys comments up

Please do the math before considering gasoline must be bad -- and producing hydrogen from gas is silly.

1) the article is talking about stripping hydrogen from gas in a fuel cell -- no mention of using combustion -- but the article does not state what the by products will be

2) Electrolosis has never been an effecient way or obtaining hyrdogen - at least not on Earth - this is a matter of energy, it takes more energy to release the hydrogen that the hydrogen is worth.

3) Pv=nRt
1 kg of gasoline can be held easily in a gas tank -- but if you wanted the equivalent energy in hydrogen of 44.4 MJ in a container of similar size lets sat 15L - which is a lot bigger than you need @ around 70 Farenheit or 296K -- the equation becomes

P = ( 0.31 * 8.314472 * 296 ) / 15
= 762.93 Pascals ~ 7 atmospheres

1 kg of gas is .72 L
10 kg of gas= 444 MJ

El_Nose
4 / 5 (2) Jul 20, 2010
cont...

but just 1 kg of hydrogen needs a container that can hold 2289 Pascals of pressure -- that is not gonna fit in a car my friend. And if you put say .5kg of H in a tank you have about as much energy as 2 gallons of gas.

energy density per kg hydrogen blows everyone away at 142 MJ/kg hyrdogen pound - or kg per kg is a beast. Unfortunately NO ONE can carry around a kg of hydrogen

4)this is a viable solution - while we work on how to transport pure hydrogen, and produce it cheaply.

5)
Electrolosis could be achieved at high temperatures in non-polluting nuclear generating stations, i.e. zero net carbon.


well yes this is true -- but it is a waste of energy that could be offsetting the use of coal and oil power plants. And nuclear reactors do have a very real waste product. While I am all for creating nuclear plants like daisies all over the world -it does not deal with the issue of waste storage. Or the fact that nuclear fuel is a heck of lot more rare
Skeptic_Heretic
not rated yet Jul 20, 2010
but just 1 kg of hydrogen needs a container that can hold 2289 Pascals of pressure -- that is not gonna fit in a car my friend. And if you put say .5kg of H in a tank you have about as much energy as 2 gallons of gas.
Assuming your math is correct that would be a tank that holds a measley 22 atm of pressure, for reference most pressurized gas tanks can withstand about 5x that pressure on land. Secondly gasoline has a far higher energy density than hydrogen but you're greatly underestimating hydrogen with your above figure.
gunslingor1
not rated yet Jul 21, 2010
El Nose... fossil fuels shouldn't be used... there are byproducts.. very little difference between burning hydrocarbons or stripping off H atoms.. It's still a somewhat uncontrolled random chemical reaction with infinite varieties of byproducts including volital organic compounds.

I do realize electrolysis is somewhat inefficient... 60% efficiency is achievable with traditional methods... 90% is achievable with high temperature modern reactors. My point is that this will be more efficient than charging stations... you already loss 25-35% on transmission lines alone... plus, charging is an inherently inefficient process... batterys get hot, current is wasted to ground.

It doesn't matter though, we have more important issues. Either H2 or electric or both at the same time, it doesn't matter at this point... as long as we stop burning (excluding stuff that produces water like H2). Both fuel sources have advantages/disadvantages, both are perfectly good solutions if designed right.
Javinator
5 / 5 (1) Jul 21, 2010
It's still a somewhat uncontrolled random chemical reaction with infinite varieties of byproducts including volital organic compounds.


There are no chemical reactions that have infinite varieties of byproducts. If you know what's going into the reactor you generally know what's coming out. That's just how chemistry works. Your byproducts and their concentrations will be based on the operating parameters of the reactor (pressure, temperature, initial concentrations, etc.)

I do agree that burning methane and steam reformation are similar. In the beginning you start with CH4 and O2 and in the end you'll end with CO2, H2O (and other lesser byproducts depnding on completeness of combustion etc)

The only difference wrt environment is where the reactants (pollutants) are released. Burning methane will release the products of the combustion reaction at the source of combustion. Generating hydrogen from methane will release all of the byproducts at the refinery/plant except H2O
CavemanDev
5 / 5 (1) Jul 21, 2010
El Nose,

First, the article is not talking about "stripping hydrogen from gas" in a fuel cell (which, btw, is an incorrect statement. Stripping is the process of using a carrier gas to remove volitile species from a liquid mixture). The article is talking about using hydrogen gas that has been previously produced from fossil fuels, and dealing with any impurities that would result from that.

Second, the idea with electrolysis is that you can use OTHER energy sources to produce hydrogen. The fact that it is not economical now does not mean it won't be in the future once fossil fuel supplies run short.
CavemanDev
5 / 5 (1) Jul 21, 2010
The fact that nuclear waste is hard to handle is an issue, but keep in mind that the actual volume of waste is very small. Coal produces other nasty species that are also difficult to deal with - coal ash contains heavy metals that can be a problem to dispose of properly. Most of this ends up in landfills.

I'm not saying that's as bad as nuclear waste pound for pound, but I don't think people realize that these things can have as big an impact on their health and well-being. Especially considering that coal ash production is measured in millions of tonnes.
gunslingor1
1 / 5 (1) Jul 21, 2010
Jav-symantics
all refining processes result in impurities. long chain fatty acids, amino acids, etc are all present in the gasoline. Anthing that was once alive burns unpredictable, life just necessitates the largest and most complex of molecules. Just take a simple pile of a single protein, each time you burn it, you'll get new compounds. Infinitely is always relative budy.

Caveman,
Please realize that .02% of the weight of most types of coal is uranium and other radioactive chemicals. What this means is that a Coal plant puts more uranium into the air in a five year period than a nuke uses and stores in it's 50 year life span. Coal is actually more valuable for the uranium it contains than for burning. Which is better, uranium, mercury, large quantities of CO2, SOx, Nox, mercury, arsenic, thousands of volital organic compuns, and more, going straight into the air we breath... or a nice discrete flask of contained and controllable uranium every 2 years?
Skeptic_Heretic
5 / 5 (2) Jul 21, 2010
Jav-symantics
all refining processes result in impurities. long chain fatty acids, amino acids, etc are all present in the gasoline. Anthing that was once alive burns unpredictable, life just necessitates the largest and most complex of molecules. Just take a simple pile of a single protein, each time you burn it, you'll get new compounds. Infinitely is always relative budy.

No, "infinite" isn't relative. Secondly if you burn a pile of proteins you will not receive an infinite number of compounds nor will the concentrations change. Chemistry isn't up to the observer, there are rules, and with those rules, predictable results.
Javinator
3 / 5 (1) Jul 21, 2010
The purpose of a refinery is to remove impurities and to separate the different hydrocarbons from one another based on chain length. There are often multiple columns in series to further refine the products.

Gasoline does not burn differently with different reaction products every time. If it did then cars running on wouldn't work very well because of how unpredictable the energy of combustion of the fuel would be (different products means a different exothermic reaction which means a different energy output).

WRT nuclear:

There's a HUGE difference between the natural uranium that occurs in the ground and the radioactive fission products that are produced in a nuclear reactor. U-238 from the ground is an alpha emitter. That basically means don't eat it and it won't hurt you. Fission products emit high energy beta/gamma radiation. You'd never get close enough to spent fuel for the alpha to be an issue.

I actually support nuclear, but you're giving some pretty inaccurate info
Skeptic_Heretic
2 / 5 (1) Jul 21, 2010
There's a HUGE difference between the natural uranium that occurs in the ground and the radioactive fission products that are produced in a nuclear reactor. U-238 from the ground is an alpha emitter. That basically means don't eat it and it won't hurt you. Fission products emit high energy beta/gamma radiation. You'd never get close enough to spent fuel for the alpha to be an issue.
Fission products only emit high energy radiation when they are enriched or fissle. U-238 is not fissle, nor would a typical stage 3 reactor be what we want to build seeing as we've upgraded the technology by leaps and bounds.

Nuclear waste is simply nuclear fuel for another reactor type. Our nuclear policies and bad propaganda give the false impressions above that you're trying to dismiss but accidentally reinforcing.
Javinator
5 / 5 (2) Jul 21, 2010
Coal is also most definitely NOT more valuable because of the small amount of uranium it contains. Uranium is mined from uranium mines. It is not refined from coal because it would not be worth it for the small amount that you'd retrieve.

gunslingor1
not rated yet Jul 21, 2010
Skeptic,

Infinite numbers do not exist, there is no value associated with infinity in the real world. It just means more than we can count, more than we can observe or more than we know. It's a theoretical concept to make up for unknown extremely large quantities in physics.

your right, a pile of proteins won't produce a number of compounds that continues forever, but it will produce different things... hell forget about the pile.. forget proteins. Lets assume you burn DNA. There are 100 billion rungs in a humans DNA, each containing 2 of four aminio acids which are highly complex molecules in themselves. When you start attaching oxygen to the rungs, they will break off in an unpredictable manner, unless you happen to be controlling exactly where and when the oxygen is attached to the long chain which you do not do for a fuel. Even hydrogen burning: nitrogen in the air is also oxidized to produce NOx. The air contains microbes which burn, etc. We're not in the lab here.
gunslingor1
5 / 5 (2) Jul 21, 2010
Alright guys, this conversation has turned a bit facetious.

We all are on the same side. It's difficult to get ones point across on a thread, especially with the boss right around the corner.

I'm out. See you next thread.
CavemanDev
not rated yet Jul 21, 2010
@gunslingor1,

You seem to think I was arguing against nuclear. I was not. HOWEVER, your statements are not necessarily correct.

Nuclear waste is not *just* uranium. It is a mixture of fission products of varying activities, most of which are unpleasant in some regard, in addition to any uranium that does not fission or transmute.

Most of the ash and crap from coal is contained (at least it has been since the 80's). Yes there is still lots that comes out. In principle, coal waste is easier to deal with. The catch is that there is a lot more.

I agree with you about preferring what a nuclear reactor puts out, but your hyperbole gives the wrong impression that nuclear waste is safer than coal waste.
Javinator
not rated yet Jul 21, 2010
Nuclear waste from some reactors can be used in other reactors (ie. PWR reactor waste still contains a high U-235 concentration than the natural uranium used in CANDUs), but the waste itself is still highly radioactive until properly processed.

U-238 is not fissile, but will absorb neutrons in a reactor and will eventually beta decay into plutonium which IS fissile.

When a fission event occurs in a high mass atom (uranium, plutonium), fission products are formed. The ratio of neutrons to protons in stable U and Pu nuclei is actually higher than that of the nuclei of the daughter products (Xe for example). When a fission event occurs, the high n:p ratio from U or Pu remains in the daughter products resulting in unstable (or radioactive) nuclei. It's these fission products that release the high energy gamma and beta radioation as they decay.

The reason nuclear is still better in spite of the dangerous waste is because of the ridiculously low volumes of waste for the energy made.
Skeptic_Heretic
5 / 5 (1) Jul 21, 2010
Skeptic,

Infinite numbers do not exist, there is no value associated with infinity in the real world.
Infinity is the presence of ALL values, this is why infinity is both real and not relative.

your right, a pile of proteins won't produce a number of compounds that continues forever, but it will produce different things... hell forget about the pile.. forget proteins. Lets assume you burn DNA.
Here's the problem. DNA is not a single molecule or collection of molecules. It is a moniker used to depict billions of different molecules so of course you'll get billions of different products from combustion of "DNA".

Gasoline is a combination of a fixed quantity of particular hydrocarbons. Those hydrocarbons react in a particular way based upon the environment they are reacting in. When you combust gasoline under standard conditions you receive H2O, CO, CO2, and a few other reactants in fixed quantities. No grand hypothetical needed.
taka
1 / 5 (2) Jul 21, 2010
I point that hydrogen is harder to handle, not more dangerous! Whenever there is energy there is also the danger. But any danger can be dealt with and eliminated; the question is on money (and weight, and volume, and waste products and so on...). I can easily handle enough gas to travel 100 miles with bucket. Tray that with hydrogen... The storage in the car is only the beginning of problems.

So even if there is available green and cheap hydrogen the wisest thing will be to use it to synthesize gas from it... Or may be sugar, but something tenser anyway. The energy density on normal pressure is what matters.
Skeptic_Heretic
not rated yet Jul 21, 2010
Taka, are you jsut trying to be difficult or do you have a valid point to make on the topic?
taka
1 / 5 (1) Jul 21, 2010
It is amazing how some are unable to see simple truth that is under their nose. Sometimes I am unable to resist and point on it, like this child who tell that wait a moment, the King is naked. Skeptic_Heretic, know that classical tale? Dangerous exercise of course, without anonymity I definitely did not dare. Some had even made effort to vote me down, for something just stupid nobody won't bother. The bad news is the truth does not change if you hide it under carpet.

What the topic by the way, I read comments and forget what about the original article was.
Javinator
Jul 21, 2010
This comment has been removed by a moderator.
taka
1 / 5 (1) Jul 21, 2010
No need to go so high. Just a bit higher the nuclear waste is dealt with... There are also infinite numbers, DNA burning (DNA is simple molecule by the way, contain only 4 different nuclear acids and some sugars) and other interesting staff. Who cares what is on the top after that?
Javinator
not rated yet Jul 21, 2010
I love it when discussions go on tangents. You learn more than you thought you might. As long as post are relevant to those about it what does it matter if it goes off topic?

What the topic by the way, I read comments and forget what about the original article was.


Who cares what is on the top after that?


Apparently you do.
Skeptic_Heretic
not rated yet Jul 21, 2010
DNA burning (DNA is simple molecule by the way, contain only 4 different nuclear acids and some sugars) and other interesting staff. Who cares what is on the top after that?


So go ahead and tell me what will result from the below chemical reaction.

H3PO4 plus C5H10O4 plus C6H14N2O2 plus C5H5N5 plus C5H5N5O plus C5H6N2O2 plus C4H5N3O plus O2.

Make sure you account for your percentages based on the composition of each within your own DNA code and adjust the ratios for each based upon their presences within each cell.
taka
1 / 5 (1) Jul 22, 2010
Sorry, Javinator, actually I agree with you. Just I get pushed and went a bit sharp.

Skeptic_Heretic, this jour reaction will give really simple result - H2O, CO2, NO3. Of curse, if there is not enough heat or O2 it will give also a lot of intermediate things, but these things you will get independently of from what you start with.