Carbon Capture

...but the current H2 process is extremely good for CO2 recovery. The current H2 process makes a very pure CO2 by-product stream that can be, and sometimes is already, easily recovered by scrubbing to make food grade CO2 product. If someone insists the CO2 could be piped underground to sequester it.

The OP chemistry may have some use, but I doubt commercial large scale H2 production is going to compete with today's steam methane reforming, even if we have to sequester the CO2.

Where it might fit in is on-board a car to make H2 from methane. So far it's been hard to find a good way to make H2 on board from other fuels, but that's certainly been tried.

 

Clever approach.

Bob Wilson

 

You need a lot more methane which is probably lots more fossil fuel as this doesn't get the energy of burning the carbon. Think of it this way, you frack to get natural gas, then you take a lot of the energy and make coal and some is available as hydrogen.

Wouldn't it be easier to stop mining coal and burning it, then make coal from natural gas?

Economics is what stop that. Hopefully regulation can slow coal burning.

They claim by 2020 there will be a plant in australia that produces hydrogen from coal, sequesters the co2 and then ships the hydrogen to japan. That seems really expensive but cheaper than this process.

 

But then you probably have added $3/kg to the cost of the hydrogen that is already over $13/kg in California. That is why they won't do it.

On a natural gas power plant sure maybe, but way to expensive for hydrogen for transport fuel when its competing with electricity and oil. But yes better than the method outlined here.

 

My understanding is:

CH{4} + 75.3kJ/mol -> C + 2H{2}​

Source: https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/49_1_Anaheim_03-04_0973.pdf

So we need some energy:

C + O{2} -> CO{2} + 393.5kJ/mol

75.3kJ/mol / 393.5kJ/mol ~= 20%

or​

solar/wind and find something useful for the carbon​

So I'm open to this approach because it results in two useful products.

Bob Wilson

 

You are taking the methane and other hydrocarbons in natural gas then not using the reaction C + O2 -> CO2. That means you are giving up a lot of the energy.

Sure, its worse digging up and burning coal, so why not use the energy in the carbon in natural gas and not dig up and burn the coal. That coal is going to also produce a lot of mercury and ash, the diging it up causes a lot of water pollution.

Yep. and right now in the US natural gas is cheap, but its not unlimited. Its going to take a lot more natural gas if you don't burn the oxygen. That will raise the price of natural gas, making coal more favorable. Will you dig up more coal to make that up? If so then its a loser in terns of ghg and economics.

Yes it will be okay, but will china not burn more coal if natural gas becomes more expensive? You need to find a way to make it economic.

Adding wind to the grid offsets natural gas. Wind and natural gas ccgt reduce coal.

How much money will it take to consume more natural gas in this reaction.

If wind based hydrogen costs $6, SMR hydrogen $2 and this process $5/kg but consumes twice the natural gas as SMR, why not do half wind half SMR (also $5/kg). That might cost exactly the same as this process, but consume 1/4 the natural gas. Eventually if you are advocating higher and higher consumption of a resource, you will raise the price. Fracking is not an environmentally free process there is water pollution involved that must be counted. GHG is not the only important thing.

 

Bob the key to this "improvement" over CCS (carbon dioxide capture and sequestration) is that you don't ever use that energy going produced by oxidizing the carbon. CCS is not 100% effective, but I have to believe that natural gas has some value and using a lot more also may not be great (leaks in production probably mean using more also produces some ghg, as well as higher natural gas prices).

Its
CH4 + O2-> C + 2H2 +O2 - energy -> C + 2H2O + energy

versus

CH4 + 2H2O + 2O2 -> CO2 + 4H2 +2O2 - energy -> CO2 + 4H2O + energy

In the second case we get a lot more energy out of the reactions but get extra co2 that we don't want. I don't know the full energy ballance because I don't know the efficiency of this molten tin process to produce the hydrogen, but I would be surprised if it didn't take twice as much methane per molecule of H2 assuming methane is the energy that is consumed in H2 production.

 

Agreed but sequestering carbon (or using it for industrial processes) should be quite feasible. However, I'm also curious when compared to electrolysis energy:

H2O +285.8kJ/mo --> .5O2 + 1H2 # Need to double it to make the equivalent amount of hydrogen

2H2O + 571.6kJ -->. O2 + 2H2 # The same amount of hydrogen as reducing CH4

So I'm seeing a 571.6 / 75.3 or ~7.5 times improvement in hydrogen production over electrolysis.

Then comes the fun part, seeing if the carbon can become a structural product like nano-tubes or carbon-fiber strands. Something strong enough to make vehicle body parts. Hummmmm, diamond coated windshields anyone?

Bob Wilson

 

Interesting press release about a CO2 scrubber...

Breakthrough CO2 Technology Eliminates Vehicle Exhaust Fumes At The Source

States Dr. Michael Kralik, Senior Physicist and Chief Science Officer for Nova: "Carbon dioxide molecules behave according to a well-known set of harmonic resonances which generate the fields that attract and bind the oxygen atoms to the central carbon atom. By subjecting the gas to intensely dissonant field effects, we are able to disrupt the spin polarity and oscillation frequencies that bind the atoms together."​

Got that?

 

:

You have a lot magic going on here. In cxidization of methane we have
CH4 + 2O2 -> 810 kJ + CO2 + 2H2O

SMR then oxydation
CH4 +H2O +2O2 -> CO2 + 3H2 + 3/2 O2 + 87 KJ -> 810 KJ + CO2 + 3H2O

Partial oxydation of methane, then oxydation
CH4 + O2 -> C + 2H2 + O2 - 75 kJ -> 407 KJ + C + 2H2O

btw
Energy from Fossil Fuels
2H2O -> 2H2 + O2 - 482 KJ -> 2H2O

In other words if processes were 100% efficient producing the carbon versus carbon dioxide reduces energy from 810 to 407 from oxidation of methane. The process only produces 50.2% of the energy, but wait its worse. These systems aren't 100% efficient, say they both are 80% efficient. In SMR we use appoximately 20%x810 = 162 KJ - 87 KJ from the reaction = 75 KJ of energy from more methane burn to keep it going. With inefficiently thrown in we get about 2.7 molecules of H2 from each SMR molecule of CH4, with the difference in energy given off in heat.

Let's do the same with this partial oxydation. 482 (energy of resulted hydrogen) x 20% = 96 KJ + 75 KJ needed for the reaction = 171 KJ needed, lets say we get it from oxydizing the hydrogen, we get 1.4 Molecules of H2 from each molecule of methane, assuming this rough guestimate of 171 KJ needed. That gets you 92% more Hydrogen for each molecule of H2, with the difference coming from extra hydrogen from splitting water and less methane being burned to drive the reaction. Would need real efficiencies to get better estimates, but this requires in the ball park of twice the methane consumed for each molecule of hydrogen since much of the methane's energy is used breaking carbon hydrogen bonds, but energy is not released by creating new bonds.

The process has been around since the 80s, and could easily be used, although is probably much less than 80% efficient as I used above, while SMR often is higher. The problem with this production is how much carbon black do we need versus hydrogen.

http://www.carbon-black.org/index.php/what-is-carbon-black

If we produced 3% of hydrogen by this method, that would produce more carbon black than is produced today. Hydrogen and methane are just much more important comodities. Sure if you produced 10% of hydrogen this way today, price would drop on carbon black to next to nothing and you would need to dispose or store some more of it every year.

I'm not sure how if demand for hydrogen spikes and we use this method carbon black is a valuable product at all. Its better to judge it purely on CO2 production against much higher methane consumption and higher cost of the hydrogen (because it is consuming more fossil fuel to produce the same amount of hydrogen). THe last I checked the problem with using hydrogen for transportation was more about high cost of the hydrogen and refueling network, and the large demand on methane. This method makes both of those problems worse, while attacking one that I'm not sure exists. Why not use that difference in government cash to shut down old coal which would reduce ghg much greater per government dollar.

 

The space elevator, if ever implemented, will need a large amount of carbon for the lift cable.

Carbon to replace steel and aluminum in aircraft and other transportation appliances help reduce the amount of fuel needed to operate them.

Carbon to replace structural steel and concrete will also allow skyscrapers to build higher.

Costs may block much of this in the short term, but in the longer term I suspect there will be a good market for non-combustion uses for the carbon output.

 

Carbon fiber is made by carbonizing plastic strands. Powdered carbon won't help there.

 

Hey the numbers were close enough, it was the way bob was using them that made me look them up.
+1

In CCS we can sequester about 90% of the CO2 for around 10% of the energy. Is that last 10% worth all the fracking pollution and the higher price of the hydrogen and methane?

Only if you aren't allowed to make it the other way. If you are allowed to do smr then then this process won't be able to compete economically.

Why not just tax the coal? What is the point of taxing the cycling natural gas plants too? If you do both then you keep burning more coal and produce more ghg than if you just tax the coal.

If hydrogen is competing with oil for transportation, why make it sequester the carbon and make it even more expensive than gasoline? It doesn't make much sense.

Together those policies produce a lot more ghg, than simply taxing the coal and the oil. It also reduces OPECs power if we just tax the oil and not ghg from alternative lower ghg methods for transportation.

There is no free lunch in the chemistry. The real cost of SMR which uses some of the power of oxydizing the carbon in methane to split water is probably the best economic way to make hydrogen, unless you are going tax coal enough to eliminatte its use. The best renewable way to make hydrogen is splitting water with off peak wind. The government can distort these though.

But hydrogen production is tiny in terms of global ghg emissions. Coal electricity then oil transportation are the big ones. If governments concentrate here its not going to do much good.

Not sure where you are coming from here, coal does not provide cycling power. For that you are talking natural gas or biogas ccgt or ocgt plants to play with wind and solar. So yes, you could instead of wasting the methane by making hydrogen production less efficient, use it to in fast cycling ccgt plants along with renewables to replace the coal. We don't need to pay cash to shut down coal, just produce regulations that stop favoring it, and it will naturally go away. Some of the money you don't spend on this hydrogen and carbon from methane could be spent upgrading the grid, and encouraging renewables and ccgt plants.

I thought the argument in needing coal, that industry puts out, is there isn't enough natural gas, and coal is cheaper. This scheme definitely plays into keeping coal arround, if you make methane more expensive.

 

a gallon of gasoline produces less than 10 kg of carbon dioxide. To make it cost more than this hydrogen you would need to tax it at $0.50/kg of carbon dioxide- $5/gallon tax. But if you tax coal electricity at $0.50/kg then you would be taxing it at about $0.50/kwh. The economies in the Midwest and eastern states would grind to a halt. You simply can't tax it that high without massive unemployment. So how is it going to be cheaper than gasoline?

Pick a value and look at the consequences. If you need to make hydrogen this way, then fuel cell cars make even less sense then they do today. You can't greenwash the fossil without massively making the cost even higher.

$1/gallon gas tax, $50/ton coal tax would reduce greenhouse gas without nearly the cost in jobs. If you insist on doing a carbon tax on all carbon the odds are you will simply do what happened during clinton's attempt, and end up with more coal and ghg.

 

I'm not thinking of carbon fiber as is commercially available now. I'm thinking ahead to graphene and nanotubes, which are stronger.