Electrochemistry

[P-man]

Hey I want to research electrochemistry, seeing as I'm doing a project on fuel cells, I thought it would be a good time to start. Where can I start? Do you know any good books? Websites?

[UncleAl]

Google

"electrochemistry" textbooks 63,300 hits

"electrochemistry" tutorial 97,200 hits

 

Library. The base electrochemistry is not a big deal. The little stuff (overpotential, kinetics, efficiency, poisoning, lifetime) will kill you. Fuel cells are physically delicate, finickey about what they eat, inconvenient to maintain, expensive. You can get around some of that, but you cannot get around all of that. Inconvenience is conserved. Fuel cells are used when there is no better solution, or when somebody else is picking up the tab, or when you have an acre of floor space decorated with engineers (e.g., molten carbonate fuel cells for utility power backup).

 

"Reality must take precedence over public relations, for Nature cannot be fooled." Richard Feynman.

 

The E*L*E*C*T*R*I*C car. Physically impossible, politically maladroit.

The H*Y*D*R*O*G*E*N car. Worse.

[P-man]

Hey! Fuel Cells are good. They're not impossible OR expensive. Ballard has reduced the platinum content in the catalyst by 40%, therefore making it cheaper.

http://www.ballard.com

[Tormod]

Hey! Fuel Cells are good. They're not impossible OR expensive. Ballard has reduced the platinum content in the catalyst by 40%, therefore making it cheaper.

http://www.ballard.com

 

Please be more specific when posting links - this looks like an ad, not a relevant post. Can you point us to a more relevant page at their site?

[CraigD]

The E*L*E*C*T*R*I*C car. Physically impossible, politically maladroit.

Politically maladroit, I can see, but physically impossible?! One sees electric cars of all shapes, sizes, and uses every day. Your statement is akin to claiming that a hot air balloon is impossible, just because it’s less practical for a specific application than other aircraft.

The H*Y*D*R*O*G*E*N car. Worse.

I’m suspicious that the recent romance of government and business with the hydrogen fuel cell electric car is mostly an appeal to a well-meaning but poorly-informed “green” public (eg: “purchase you next overpriced new vehicle from us – the money goes straight into research to produce a new generation of pollution-free wonder vehicles”) What’s worse, some well-intended legislation, such as California’s zero-emission vehicle incentives, actually appear to be working against the introduction of lower polluting vehicles.

 

Other than being difficult to contain enough of to get you very far, hydrogen is a wonderful fuel. I’m troubled that, with all the publicity about hydrogen fuel cells, power and transportation planners seem to have forgotten that the simplest way to get mechanical energy from hydrogen gas is to simply burn it, and use the heat in any of a number of heat engines. Combustion by-products prevent such a system (unless a closed H & O system) from being completely zero emission, but it’s dramatically cleaner than gasoline or diesel engines, even considering emissions from power plants required to produce the hydrogen.

[CraigD]

Hey I want to research electrochemistry, seeing as I'm doing a project on fuel cells, I thought it would be a good time to start. Where can I start? Do you know any good books? Websites?

Per my and UncleAl’s previous posts, you might want to broaden you research to take in the larger picture of energy production and use. At any given time, the technical solutions publicized and favored by government and industry are not always optimal.

[P-man]

I'll get back with a better link to a great video.

[UncleAl]

Politically maladroit, I can see, but physically impossible?!

You have a gas tank filled with 80 lbs of gasoline. You inhale several times that much air by weight, burn the mixture, etc., and the car goes from here to there. Maybe 300 miles later you refill the tank with 70 lbs of gasoline.

 

You have a 1200 lb battery pack. You drive maybe 60 miles. How much does the battery pack now weigh? 1200 lbs. Gas tanks don't wear out when you fill them. Deep discharge and sizzle recharge a lead acid battery daily you have maybe 6 months usable life - as physical reality demonstrated.

 

Self-contained electric vehicles are (low-load)(time), low velocity, short range. Golf carts to forklifts. You don't have 100 horsepower golf cars or 80 mph forklifts. The E*L*E*C*T*R*I*C car died the first business day after government subsidies were suspended.

 

hydrogen is a wonderful fuel.

Hydrogen is a disaster as a fuel. It is the worst physical leak, the worst virtual leak, it embrittles steel, and its combustion produces massive quantities of nitrogen oxides. You can't mine hydrogen, you make it Second Law of Thermodynamics. There is no hydrogen distribution network.

 

Housewife with room temp IQ gets out of car and hooks up to 23 kelvins liquid hydrogen refill? 10,000 psi hydrogen refill? You gotta be kidding. I worked in a place that was plumbed for hydrogen for quartzblowing torches. If a line did not hold pressure, everybody slopped diluted shampoo everywhere, with vigor, until the leak was found. They didn't need a foreman to tell them to work faster or more diligently. BOOM!

[CraigD]

Ok, so hydrogen is more difficult to distribute and store than gasoline, and harder to get to as high an energy density. The clear advantage it has is that it can be created from a variety of sources of energies, particularly solar electric and other “inexhaustibles”.

 

UncleAl, If I recall correctly, you’ve pointed out in previous threads that other renewable fuels such as alcohol and biodiesel are very energetically inefficient, and potentially more polluting than oil products. Yet, the scientific consensus is that, eventually, humankind will no longer have adequate supplies of oil to produce the quantities of gas and diesel required to supply our mobile power needs. Predictions as to when this crisis will occur vary, but only a minority maintain that it will never come.

 

Even if such promising sources as ocean-floor methane hydrates prove abundant and accessible, they only postpone, not eliminate the inevitable exhaustion of hydrocarbon stored energy. I’m unaware of any efficient technique for converting energy from inexhaustible sources into hydrocarbons (though this could simply ignorance on my part).

 

:confused: If not high-energy-density mechanical (eg: flywheel, compressed gas) chemical (eg: battery), hydrogen or another renewable, what do you propose to take the place of hydrocarbons for our future mobile energy needs?

[UncleAl]

what do you propose to take the place of hydrocarbons for our future mobile energy needs?

Nothing. First World civilization will collapse after the planet is exhausted of its minable dense energy reservoirs. The first big hit will be Baby Boomer retirement in America and Europe imploding the Welfare State by 2015. The second big hit will be the end of recoverable petroleum by 2050. The rational act is to build nukes, many many nuclear power reactors with full fuel recycle, and stop burning petroleum. That may give another 20 years to discover a way out in physics. Or not. Controlled fusion is hopeless crap.

 

What usable hydrocarbon resources remain after oil? Coal is near useless for conversion to liquid fuels or petrochemical feedstocks. It is an incredible sponge for hydrgen to get rid of the unsaturation. it is not a source of linear hydrocarbons short of conversion to synthesis gas and Fisher-Tropsh reassembly. Horrible and inefficient. Huge excess CO2 emission compared to burning petroleum.

 

1) Continental shelf methane hydrate. That is a ***** to recover. Pressure destabilization of the massive deposits could lead to positive feedback runaway decomposition to free methane. That in turn has two possible ends: Setting the local atmosphere on fire or creating a very real intensely augmented Greenhouse Effect. Adding few ppm of CO2 to 380 ppm already in the air is piffle. Adding ppm methane to zero methane closes a major atmospheric infrared transparency.

 

2) Athabasca tar sands. Tar sands require at least 30% of recovered energy for beneficiation. The net recoverable deposits are then 1/3 smaller than stated and they are profligate CO2 emitters/joule produced. The product is heavy oil. It requires extensive reforming and refining, and eats lots of hydrogen doing it - more CO2 emissions and non-recoverable energy input before it is burned as fuel.

 

3) Colorado oil shale. Oil shale is really a low rank coal (5-25 wt-% organics) in calcareous marlstone (sedimentary rock from lake bottom varve deposition). Shale oil is freed by thermolysis. That popcorns the stone and produces vast amounts of lime (and CO2). Where are ya gonna stick the residue? It won't all fit back in the hole. Groundwater leachate will be pH 12-14 forever. Shale oil has a pour point around room temp (potentially embarrassing in pipelines in the winter). Entrained rock dust is incredibly abrasive during transport and valving. Shale oil is is heavily unsaturated - another hydrogen sponge. It is rich with nitrogen (percents; kills acidic zeolite supports) and arsenic (tens of ppm; kills noble metal catalysts in the zeolite). Shale oil is the perfect refinery poison.

 

Social collapse around 2015, technological collapse around 2050. The only uncertainty is Bush the Lesser. He has been remarkably successful dragging the date for Ragnarok into the here and now by exhausting all US financial reserves and elasticities. 1929 was small stuff. Have a nice day.

[GAHD]

Now that all the doomsayers have spoken, shall we actually discuss electrochemistry?

[HydrogenBond]

The current theory for the center of the earth is a metallic iron (nickel) core. Iron wants to rust or form cations on the surface of the earth because the surface defines an oxidation potential. If this earth core theory is true, we should be able to tap into the core's amazing reduction potential, i.e,, extra electrons that can be oxidized by the surface oxidation potential. The earth should be like a giant battery. We can then use this electrochemical potential to generate hydrogen gas, oil or anything reduced we need on the surface.The supply should theoretically be endless, at least for humans, seeing that the metallic core is 1000 times more massive that the oceans.

 

There is no reason why electrons can not be condicted through the plasma mantle and then through the mineral water continuum up to the surface. This should create a potential between the oxygen atmosphere and the oceans. The oceans are slightly negative or pH slightly basic. The evaporation of water by the sun, creates electrophilic potential within the hydrogen of water, i.e, break hydrgoen bonds, this should further increase the electrochemical potential between the core and surface. Rain reduces the water vapor by allowing the hydrogen of water to once again share electron density as liquid water.

[nkt]

Harsh but fair.

 

Where to start with rubbishing HydrogenBond's idea?

 

Firstly, it's rather tricky to get to the magma. Secondly, using up all our fresh water is not a good long term plan. Thirdly, rust (Fe02, Fe2O3) is bigger than Iron (Fe). Fourthly, what percentage of global O2 would you like to see removed? Every time you burn anything it would deplete the O2 in the air further, as it would create water. Water which you then convert into rust, to recycle the H2. Wonderful! No air and no water, and an earth that was split apart.

 

Of course, that's only if you can get it to work. Which I seriously doubt. Thank God!

[HydrogenBond]

It won't work because there is not an iron core in the center of the earth. That is 1960's speculation due to iron being magnetic, such that 2+2 equals five. I was poking fun at that theory. If it did exist the potential could be slowly conducted with H protons from the surface due to critical water reaching the mantle, electron from the core would use this H migration to flow countercurrent the surface. But the ocean levels are not dropping, i.e., losing hydrogen. There no electro-chemical potential of the magnitude suggested by an iron core.

 

If we did have an iron core, we would use the slight negative charge within the ocean to feed electrons to atmospheric oxygen. We burn the same amount of oxygen with fossile fuels, just in this case we would not make CO2 or NOx. At the same time, nobody is worried about the oxygen levels dropping through combustion because it is renewed all the time. The supposed iron core is 1000 larger than the ocean and should never wear out. The ocean could never become neutral, because they are buffered by the minerals, and would be renewed by the core.

 

UncleAl lighten up.

[nkt]

So your post was one of those mysterious ones that aren't a joke until you are called on it?

[UncleAl]

It won't work because there is not an iron core in the center of the earth.

******. The Earth's core is a ball of iron the size of Mars - and not merely from satellite orbit and seismic data,

 

http://www.es.ucsc.edu/~glatz/geodynamo.html

http://www.es.ucsc.edu/~glatz/GarysImages/inner_core.gif

[CraigD]

It won't work because there is not an iron core in the center of the earth.

OK, I’ll bite. Why do you believe there’s not an iron core in the center of the earth? In particular, where did all the primordial iron go? Stellar spectroscopy estimates a greater amount of iron than can be accounted for by its observed presence in the crust. Is the predicted core iron dispersed through the crust and mantle, or is it not present in the Earth at all?

 

I suggest relying in a separate Earth Science thread – we’re getting far from P-man’s original questions.