CO2 Removal from Plant Stacks 3

[MJCronin]

I was wondering,.....with the current emphasis on "greenhouse gases" and global warming, how practical is it to remove CO2 from the effluent of a Combustion turbine power plant ? Are there any demo or pilot plants in operation ?

How is the CO2 collected and where does it go ?

How about a gas-fired combined cycle installation ? (The kind, of course, that is now being constructed all over the USA) If the plant emitts less CO2, don't we end up with a big pile of "something" that requires disposal ?

I realize that nuclear plants really are bad in the eyes of many, and that nobody want's them on the planet.... but, after we burn through all of our natural gas and had a few more war's in the mid-east over control of oil...... what is our only real option ??

Who knows something about the practicality of CO2 removal ?

Any websites ?

Thank You !!!

MJC

 

[jsteverm]

It is practical and there are commercial installations that remove CO2 from flue gas. With the current technology the cost effectiveness depends on the local CO2 market. If there is a greenhouse gas market then you might see more installations.

Chemical absorbtion is the most suitable method of removing CO2 from exhaust gases whre the CO2 concentration is typically between 5% and 15% by vol. There is a commercially available process which uses aqueous solution of amines as solvents. Using this process, a recovery factor of 90% of CO2 in feed flue gas is possible. The separation process of carbon dioxide by chemical
absorption consists of two steps:
1. the absorption of CO2 by chemical solvents at a low
temperature (40-65°C)
2. the recovery of CO2 from chemical solvents by using low
grade heat (a temperature in the range of 100-150°C),
usually extracted from power plants.

I think MHI is one vendor of these systems.

 

[steve58]

There is one combined cycle power plant in the United States that has a CO2 recovery plant that removes CO2 from the exhaust gases (Northeast Energy Associates in Bellingham, MA). It has been operating for 10 years and recovers the CO2 via chemical absorption. The CO2 is then compressed, filtered and refrigerated and sold into the New England CO2 market. The process design was by Fluor Daniel.

Note that, while this process does strip CO2 out of the exhaust gas, the ultimate "resting place" of this CO2 is probably still in the atmosphere. The Co2 is sold into the market and used for things like carbonation of beverages, electronics manufacturing, dry ice, etc.

 

[MJCronin]

Steve58,

Thank you for your comments.... you have confirmed what I have suspected - that the ultimate repository for CO2 (and all other greenhouse gasses) is the atmosphere....... if there is a brief stop in a carbonated beverage ( or beer, for that matter)what untimate difference does this make to "global warming" ?

I suspect that we will find that any permanent absorbtion and storage of CO2 will be far more expensive than any of our lawyer/lawmakers or environmentalists will lead us to believe.

Does anyone know of any studies or methods that are being evaluated currently ?

Are there any chemists out there in cyberspace that can shed light on any options available ?

MJC

 

[MortenA]

Well it does contribute some - since the CO2 could be produced by other means and thereby adding up instead of beeing "re-used".

There as been some "scince fiction" scheem dealing with sea bootom storage (many areas of the sea have sufficient depth to ensure that the CO2 stays liquid and liquid CO2 is heavier than water) or re-injection into oil/gas reservoirs

Best Regrads

Morten Andersen

 

[DeltaCascade]

Regarding "fossil fuels", like methane (CH4), the carbon in the CO2 (burnt CH4) comes from geological formations. CO2 can be returned to geological formations, such as commercially practiced in some enhanced oil recovery where CO2 is re-injected to oil fields. Similiarly, underground alkaline formations can assimilate CO2, etc. It is understood that the Alberta Research Council, and others, are working towards such new processes. Chemical Engineers, Geologists and Geophysicists .. there's a ground breaking combination! By then, maybe concern would arise about atmospheric O2 depletion?

Ultimately, it appears that a hydrogen based economy powered by nuclear energy will replace our oil based economies, and bio-energy (solar), like vegetable oil fuel will also help .. injecting CO2 to greenhouses sounds interesting, although perhaps expensive. Ultimately, it appears that the source of all our energy is nuclear energy...

One thing to note in a hydrogen economy, hydrogen is so light that it escapes from the atmosphere into space ... so lets not waste that. Interesting future challenges... gotta love chemical engineering...

 

We´re intrested on a CO2 flue gas recovery sistem to intal it on a thermal electrical steam plant in Venezuela. The plant has 3 unit o of 460 MW each one.

I´m making the reserch here in Venezuela but at until now we dont have much information about it, pleas if anyone can give us some information we will realy apriciate that.

 

[ceesjan]

Check

http://www.ieagreen.org.uk/capt1.htm

You will find basic knowledge of CO2 capture.
Furthermore you will find out that CO2 capture
decreases plant efficiency by approx. 10 pct
points, and will result in much higher energy
prices.

 

I want to thank "ceesjan" for the information about the web page of CO2 Capture. It realy was very helpful.

 

[quark]

I think groing trees is one option.

Regards,

Truth: Even the hardest of the problems will have atleast one simple solution. Mine may not be one.

 

[dickwilber]

MJCronin,

One question you asked in passing hasn't been addressed: why do gas-fired combined cycle plants emit less carbon dioxide?

Two answers:

1. Natural gas contains a much higher percentage of hydrogen and lower percentage of carbon than the other usual fossil fuels, coal and oil. Therefor, for a given energy output, more water vapor (H2O) and less carbon dioxide (CO2) is produced. (And so do other gas fired steam electric generating plants, but then I have heard it stated that water vapor is also a greenhouse gas - presumably, however, it is more beneficial to the environment than CO2.)

2. Combined cycle gas-turbine (versus simple cycle gas turbine) plants are much more efficient than conventional steam electric generating plants. FYI: a simple cycle gas turbine is simply a jet engine using a turbine to turn a generator; a combined cycle electric generating system utilizes the power of the jet to turn a turbine wheel attached to a generator, then runs the hot gases through a steam boiler and uses the steam power to generate additional electricity.

I am in favor of combined cycle power generation (fuels other than natural gas are also used, though they are generally less friendly to the environment than the gas fired units), even though they are partially responsible for ending my 30 year career servicing the power industry.

 

[cameo]

i would to know what is the suitable process to remove 25% CO2 to 3% CO2 in gas processing plant. whoever has any info on that matter, please let me know.

 

[MetalGuru]

Continuing along this line of queries...
I would be interested to know of any products for emissions removal from the exhaust of heavy fuel oil generating plant. - or if a similar device as discussed previously can be adapted for use with these.
I would appreciate any practical knowledge or advice, and also any other information to do with emissions and limiting greenhouse gases.

Thanks

 

[rmw]

MJCronin, and cameo,

Just look at it this way. The CO2 is present because the energy in a hydrocarbon fuel was released when its carbon and some oxygen (among other contributors to the combustion process) combined. To tie up the carbon in any fashion other than natural processes like growing trees, thank you Quark, and grass, etc., the conversion of the CO2 to any form other than beer foam is going to require more energy to reverse the process than was released in the creation of the CO2.

Frankly, I am a fan of carbon storage. First grow the tree, like Quark says, but if it is allowed to grow old and die and fall over in the forest, then, it too, releases the carbon it captured as CO2 as it rots, using again the atmosphere as the final resting place of CO2.

However, when a tree is cut down and made into a piece of lumber, and put into a use that ties it up for a long time, such as a wall in a structure, or a timber in a mine, or into a piece of paper that will sit in a file cabinet for 100 years, or be put into a landfill dump, then the carbon that the tree removes from the atmosphere is stored. Anything that is burned just releases the carbon again into the atmosphere (here we are again).

Other materials store carbon in minor amounts, but wood and paper are the best, so the tree huggers are actually working against us. Hug a logger. Build a wood house.

rmw

 

[Fizzhead]

Gentlemen:

All the ideas above have been interesting. However, I would like to point out that you have ignored the largest carbon respository on our planet, the oceans. Take a look at ocean water chemistry (not deep sequestration as was mentioned above) and you'll see that the worlds oceans scavenge CO2 from the atmosphere and convert it to carbonates which eventually are incorporated into coral reefs and limestone. They will continue to do so as long as we preserve them. One of the reasons we don't really know the global warming effects of CO2 better than we do is the lack of knowledge concerning CO2 absorption by the worlds oceans. We know it occurs, just haven't defined the mechanisms well enough to use them as an accurate part of our predictive efforts.

rmw, you are right, trees eventually grow old, fall down and decay. But, if we've planted a new tree to replace it, then we'll balance that out! However, the trees we cut right now to make all that lumber and paper are the ones that were removing CO2 from the atmosphere yesterday. Real problem is that we aren't putting them back! Worldwide, deforestation is a huge problem and this is only one of the ramifications. So please be selective about the loggers you hug!

Quark, have you tried to figure out how much beer foam we might need to generate? Seems to me that we could sit around under a tree at the seaside drinking all of that beer and consider ourselves quite the world savers!

 

[rmw]

I only hug the lawyers that replant the forests that they log, so that they, (or their children) can log again in the future. In the part of the country in which I live, there is more forest growing today than there was 50 years ago due to good reforestation techniques.

I lament the slash and burn land clearing techniques of some countries with wonderful rain forests.

Sequester some CO2, build a log house, and file away some papers.

rmw

 

[tomatge]

rmw

"I only hug the LAWYERS ..."

I suspect this is something of a Freudian slip - you know, where you say one thing but really mean your mother.

 

[rmw]

tomatge,

Good catch.

It was late, way past my bedtime. What a slip!!! Somebody sabatoged my post, I'm sure. I couldn't have said that, could I???

I am still laughing!!

I gotta e mail this to my friends. They need a laugh.

Now, go out and hug a logger. I won't want to suggest what to do to a lawyer in a forum as fine as this one.

rmw

 

[sspence]

I came across a website talking about Plasma Breakdown of CO2 & NOx into Amino Acids. Then the solids can be disposed if (i.e. landfill).

Is this possible?
(in the process of contacting my University PhD professor, specializing in Nuclear & Plasmas).

 

[davidbeach]

Somehow it doesn't sound quite right to talk about taking molecules of a few atoms and "breaking them down" into much more complex molecules.