Catching carbon: This illustration shows the layout of a plant with carbon capture and storage.
Siemens
A new carbon-capture method will be tested at a German coal plant.
A new process for scrubbing carbon dioxide (CO2) from power-plant exhaust gases could make carbon capture a more affordable option for the energy industry. The process, which is to be tested in Germany this summer, promises to remove up to 90 percent of CO2 from flue gases while using far less energy than other methods.
Existing carbon-capture methods reduce a plant's efficiency by about 11 percent. The new process, developed by Siemens, could reduce this efficiency loss to just 9.2 percent. This may not seem like much of an improvement, "but in a power plant, that's a huge benefit," says Tobias Jockenhoevel, head of the project at Siemens, in Erlangen, Germany. Capturing CO2 will always consume a certain amount of energy, says Jockenhoevel, so the aim is to find ways to keep these losses to a minimum.
In theory, 99.9 percent of the CO2 emitted from a power plant could be removed using the process, but Jockenhoevel says that 90 percent is the economic optimum in terms of infrastructure costs and how much energy is required: "The last 10 percent costs too much."
In August, the Siemens process will be put to the test at a pilot facility built by Siemens and the energy company E.ON: the Staudinger coal-fired plant, near Frankfurt. The plant will be adapted so that part of its exhaust gases are fed into a chimney containing a 25-meter-high column that gives off a solvent mist that reacts with CO2 under pressure. As the flue gases pass through the mist, the CO2 is chemically absorbed, leaving residual gases to pass out of the chimney. The CO2 can then be separated from the solvent, which can be reused.
"It's basically like washing the gases," says Jockenhoevel. It is a standard approach to scrubbing CO2; the novelty of the process comes down to the solvent used and the way it is recovered, says Jockenhoevel.
"There's a lot of research looking for new solvents," says Amparo Galindo, a physical chemist in the Carbon Capture and Storage group at Imperial College London. Currently, the most preferred solvent is monoethnolamine (MEA). "MEA reacts very strongly, but the difficulty with it lies in recapturing it so you can reuse it," which requires a lot of energy, she says.
Genetically engineered enzymes are the key to a new carbon-capture method.
Greater efficiency in solvent regeneration would be a significant step. However, paragraph 4 refers to pressurizing the entire flue gas stream prior to introduction of the mist. Depending on the pressure levels, this could offset gains in regeneration efficiency, especially since compression steals electricity whereas thermal regeneration only steals heat. Moreover, pressure vessels that can handle on the order of 50,000 cubic meters of flue gas per minute will be very large and have a high capital cost relative to liquid columns.
While the article does not have the details to compare this with other capture processes, there is lots of literature in the USDOE web site, and especially so for the sequestration partnership areas and their reports. A number of companies are still researching chemical processes for capture and there are a number of variations. There are major differences if one is to install a system on a pulverized coal plant or a gasification plant. Also, retrofitting an existing plant can be very difficult and very likely too expensive to meet any reasonable dispatch schedule.
And then there is the whole issue of pipelines and below ground sequestration.
Again I must ask WHY? Look at the long-term data and see there is no nexus between CO2 levels and temperature. But research does show CO2 critical to plant life. Why then spend a fortune to reduce CO2?
540 million years ago CO2 was 7000ppm (when land animals appeared).
170 million years ago CO2 was 1700ppm (when dinosaurs roamed the Earth)
250 years ago CO2 was 250ppm (after Little Ice Age)
currently, because of man, CO2 is 385ppm.
Plant life dies at 150-180ppm through asphyxiation.
CO2 is a finite resource. Nature has been sequestering it underground for 540 million years. At the rate of decrease over the last 170 million years, Earth would have hit 150ppm in about 10 million years. Odd as it may seem, man had inadvertently increased the life essential CO2 concentrations, and if we were to disappear today, the added CO2 probably adds another 10 million years to plant life on Earth. However, man is clever, and may find a way to bury CO2 and make it unavailable to nature at an accelerated rate. Thus, we may yet find a way to kill off most of the planet's plant life, thus ending the 3rd atmosphere.
The global agricultural growth rate has increased 30+% because of the increase of CO2 in the past 250 years. It is projected to increase further with any continued rise of CO2. What is the political end game? Are ecopoliticians trying to reduce CO2 to preindustrial 250ppm? Do you realize that we would lose the 30% agricultural gain and thus cause massive STARVATION across the planet? And do you know what happens when global concentrations drop to about 150ppm? Most life on Earth DIES. Is this what you want to promote? Does the ability of science to accomplish a task overwhelm the sensibility of whether it is right or wrong?
the whole idea hinges on political neeeds of a "NEW WORLD ORDER" run by a certain select groups who want to reduce the world populations so these groups have more easier control on the remaining folks and it makes it easier to keep the food supplies in their control so their whims are considered first above all in order to servive!
There is a far better way of using carbon dioxide which will provide economic benefit for hundreds or thousands of years to come , which is to build up the level of carbon stored in soils , thus increasing the productivity agricultural and forestry land , allowing the world to produce more food and biofuel for a growing world population . Various techniques are currently being used to achieve this such as conservation tillage , and others may become widespread in the near future such as the addition of charcoal to the soil . What this means is that we do not need to capture CO2 directly at power stations at great expense , and also we do not need a carbon trading scheme since it is in the farmers financial interest anyway to to care for their soils properly . Keep it simple .
Since it is ABSOLUTELY essential that we find ways of feeding a growing world population , soil building is something that we have to place more focus on doing . Ocean fertilization would be a good thing too .
As a timber grower with 124 acres, I agree enriching the soil with carbon is a smart use because much of it returns to the air eventually. But nature continues to bury carbon in ocean and lake sediment such that much of it is unavailable to natural recirculation. There will always be loss of carbon. The question is how fast will we lose it. Our tapping hydrocarbons is an unnatural return of carbon to the atmosphere, that has benefited all plants on Earth.
"benefitted all plants on earth"
No, it hasn't.
Many plants grow poorly with increased levels. Studies have shown that crops grow diseased and unhealthy, kind of like the herbicide that stimulates plants to grow too fast and die.
They are adapted to the current levels of CO2.
CO2, before people came on the scene changed much slower and plants evolved to current levels.
Like any nutrient, increased levels are not necessarily good. You put too much nitrogen, potassium or phosphorus or certain needed trace elements on plants and they die also. Water is also a needed nutrient but pour too much on them and they rot.
global agriculture has increased because of use of fertilizers and new plant breeds, not because of increased CO2.
Secondly we DON'T have to sequester it all underground. If we would use carbon as a primary construction material, such as we now make airplanes and bikes, it would evolve into a major industry and sequester all that carbon in human structures without having to bury it. Plus any primary emitters could actually make money recycling it into carbon girders, carbon fibers to reinforce concrete, carbon wall panels, carbon fiber cars, etc. Prices will undoubtedly drop magnitudes when these become in widespread use.
And if you're hinting that we should go helter skelter and let carbon levels top out, remember that at those times in the earth's history when carbon levels were much higher, so were sea levels and temperatures. And no people were around to lament the lack of air conditioning or to be bothered by dragon flies with three foot wingspans.
If you're not one of the 70% of world citizens who live very close to the coastlines, no problem with rising sea levels, melting glaciers that eliminate year round fresh water sources, etc.
Woops, I guess you were just making vague out of context arguments you found on some website by people desperate to deny there is a problem. Common - I won't bother myself to find real research that contradicts my view or read real science journals. Common view - I'm comfortable so nothing bad must be happening.
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protn7
72 Comments
scrubbing co2
Since enzymes work on amino acids and there are thousands of enzymatic reaction it might help to throw some enzymes into the mix along with the amino acid solvents
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ka5s
59 Comments
Re: scrubbing co2
Most of the energy from burning coal comes from oxidizing carbon. It takes as least that much energy, given inefficiencies, to reduce the product CO2 to carbon and oxygen again. Where does that energy appear in the process described here?
Reply
ms
190 Comments
Re: scrubbing co2
It doesn't. The point is not to convert the CO2 back to carbon and oxygen, merely to keep the CO2 out of the atmosphere. Various techniques have been proposed for doing this, such as pumping it into deep wells or dissolving it in rocks. At least one idea does convert it back by pumping it through growing algae; that uses solar power for the conversion.
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ka5s
59 Comments
Re: scrubbing co2
This has the consequence that we must now handle the solvents used AND store the scrubbed CO2. I expect a leak will make the news inside of fifty years.
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9012120006
1 Comment
Re: scrubbing co2
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