Gasification Technology R&D

[madokie]

Coal gasification offers one of the most versatile and clean ways to convert coal into electricity, hydrogen, and other valuable energy products.

The first coal gasification electric power plants are now operating commercially in the United States and in other nations, and many experts predict that coal gasification will be at the heart of the future generations of clean coal technology plants for several decades into the future. For example, at the core of the U.S. Department of Energy's FutureGen prototype power plant will be an advanced coal gasifier. <> Read more about FutureGen>

Rather than burning coal directly, gasification breaks down coal - or virtually any carbon-based feedstock - into its basic chemical constituents. In a modern gasifier, coal is typically exposed to hot steam and carefully controlled amounts of air or oxygen under high temperatures and pressures. Under these conditions, carbon molecules in coal break apart, setting off chemical reactions that typically produce a mixture of carbon monoxide, hydrogen and other gaseous compounds.

Gasification, in fact, may be one of the best ways to produce clean-burning hydrogen for tomorrow's automobiles and power-generating fuel cells. Hydrogen and other coal gases can also be used to fuel power-generating turbines or as the chemical "building blocks" for a wide range of commercial products.


http://www.fe.doe.gov/programs/powersystems/gasification/index.html

[eppur_se_muova]

1. And where does that CO end up? Burned to CO2, usually.

No matter whether you burn coal directly or indirectly, it STILL MAKES CO2. Coal gasification may prevent SOx and even much NOx and mercury pollution, but it doesn't stop CO2 -- which in the long run will finish off the planet.

[madokie]

2. do you understand the gasification process? not much co2 being made

[eppur_se_muova]

3. Yes, I am a professional chemist, thank you very much. C + H2O --> CO + H2

That's the basic reaction, and it has been around for years and years. Afterwards, you can combine the H2 and CO to make other things -- but mostly, the CO is used to make more H2 (and CO2): CO + H2O --> CO2 + H2 If you want, you CAN recombine the CO and H2 to make things like CH3OH and CH4 -- BUT -- almost all the H2 you are making has been made by the process above, which produces CO2 (a *small* amount of H2 comes from hydrogen in the coal). Note the article refers to 'partial oxidation' -- that's why you get H2 out -- but the CARBON is still oxidized. If you intend to use the syngas (CO & H2) to make liquid fuel, that liquid fuel will be burned to make CO2. If you burn only the H2, you had to make CO2 (by the equations above) to make the H2. Every joule of energy you get out of coal, whether gasified or burned directly, comes at the expense of CO2 production. Only the pathway varies, not the end result.

It seemed to me the point of the original article was to push this as a ZERO-EMISSIONS technology. True, NOx and SOx are supressed (as I noted before, which answered your question before you asked), which IS a good thing, but you can't call it ZERO emissions unless you consider CO2 -- the one greenhouse gas that is causing the bulk of the problem -- NOT a pollutant. This "new" development is being touted as a ZERO emissions technology because of the ASSUMPTION that all the CO2 can be pumped underground, where it will magically disappear without ever causing any problems ever (except any which is converted to fuel for transport, which will result in CO2 being dumped directly into the atmosphere). "Sequestration" is not even proven technology yet, and can't ever be a permanent solution. The more dirt you sweep under the rug, the lumpier the rug gets, until eventually the dirt comes right back out.

The whole point of "clean coal" technology is that it lets the energy companies continue to make money off of coal, rather than developing alternatives. If you *HAVE* to burn coal, it would be better to burn it by gasification, but it would be better to figure out a way not to use coal as a fuel. That is a REALLY tall order. But with coal producing CO2 in such quantities it has to be reined in, or nothing else that's done in the fight against global warming is going to matter.

edit for spelling

[madokie]

4. actually I wasn't saying anthing, just posting the article

at present coal looks as if it is a necessity. I agree we must do better but this is a step in the right direction.

[eppur_se_muova]

5. That sounds more like it, but I'm not sure the companies developing it ...

see it the same way. Once they've got the process up and running, they're not going to give up their investment easily.

Coal gasification was a great idea for the '70's, when we were trying to suppress particulate pollution, and the '80's, when we realized the impact of acid rain. But for now, it seems like we should be pushing other developments, not something that solves a small part of a big problem ... and possibly diverts money and manpower from other developments. So I tend to smell red herring whenever coal gasification comes up.

Oh, and I still don't buy the "sequestration" dreck.

[NNadir]

6. There is nothing, nothing, nothing about coal that can ever be clean.

Fischer-Tropsch chemistry, coal gasification, is the absolutely most filthy thing. It is precisely that against which all environmentalists must fight.

It is not new or inventive. It is a dangerous form of suicide that will prove fatal to most forms of life on earth.