Seeking Info on the Energy Used by German CCS Plant
September 19th, 2008
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For those who don’t know, Germany has just opened the first “clean coal” and “carbon free” power plant that burns coal and captures all the exhaust emissions, the compresses the Co2 for storage in geological formations. The plant is supposedly 30 megawatts (a peashooter) and cost about 85 million Euro (a bout 100 million US dollars).
The small pilot plant is getting a lot of attention despite being small and astronomically expensive per megawatt. Also, it isn’t exactly “carbon free” since the Co2 emissions are actually trucked away by diesel-powered trucks. But of course, this is just a proof-of-concept and officials insist that in a full scale plant it could be done much more efficiently with a pipeline.
The technology is quite complex and also energy intensive in and of itself. First, nearly pure oxygen is required. To achieve this, air must be compressed and then repeatedly put through a series of fractional distillation stages to concentrate oxygen from about 20% to more than 99%. But before it can be compressed it must first be dehumidified and filtered. So before you can even burn anything, you have to dry, filter and seperate the air to get nearly pure oxygen.
The burner must be of a specialized type which can be fueled and emptied of ash continuously without interrupting the airtight seal. It must also be a multi-stage system that returns the exhaust at high temperature to eliminate any tars of volatile organics that might gum up the complex exhaust processing afterward, even if present in only small amounts.
After the coal is burned the exhaust gas must go through a series of steps. First, fly ash and particulates must be removed. It must be put through a series of settling chambers followed by course and fine filters to keep even the finest ash and particulate particles from getting through to the next steps. Mercury vapor, volatile organic compounds and other unwanted contaminates must be removed by a series of dry and wet scrubbers.
Aside from the particulate matter, heavy metals and organic compounds, the exhaust also contains a significant amount of sulfur dioxide and other sulfur compounds. These must be removed with specialized scrubbers. Reportedly the plant uses a regenerative gypsum system, although this is likely only one stage of the desulfurization, as gypsum systems normally do not result in complete removal of sulfur compounds (necessary for the capture of the exhaust CO2), so it’s likely that the exhaust gas is finally scrubbed by lime-based scrubbers.
After this, the exhaust must be dried of all moisture. Finally, the dried, filtered and desulfurized gas is once again compressed and refrigerated to seperate the CO2 from any residual unburned oxygen, which is fed back to the burner. The Co2 which remains is compressed and stored for transport to disposal (or possibly even sale for industrial use)
Now here’s what I really want to know and have been unable to find out:
Just how much does this process take? I’m assure it’s a real lot. But when they say that the plant is “30 megawatts” do they mean the net energy produced after all the energy consuming processes are accounted for? I’d assume so. (Although it really would not surprise me that much to find out the plant is a net consumer of energy).
What I’d really like to know is how much energy is generated by the turbines of the plant and how much of that energy ends up going to run the systems and processes of the plant. It would really not surprise me at all to find out the plant actually has a generating capacity of 150 megawatts and that the 30 megawatt output is what is left over after 120 megawatts is consumed by all the distillation, scrubbers, compressors and other equipment involved.
The fact that this thing can generate more energy than it consumes (assuming that is the case), however, is still a pretty damn amazing feat of engineering.
This entry was posted on Friday, September 19th, 2008 at 11:16 pm and is filed under Enviornment, Misc, Politics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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September 21st, 2008 at 6:32 pm
Joffan said:
Unfortunately the desert location suffers from dearth of moisture that will impact the reaction rates adversely, if not bring it to a halt altogether.
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September 22nd, 2008 at 12:49 am
Cosmo said:
Yes. That is generally how it works. These idiots need a lesson in economics 101. They seem to think that expenses can just be levied on big companies and only the fat cats will pay. They don’t seem to understand the concept of ratepayers or employees or general economic health. They also seem to think that it is a good way to “create jobs” to hand out gluttonous amounts of money to pay for people to do things that don’t accomplish much and that an industry with extremely low worker productivity is somehow a good thing because it means more workers for a given amount of return.
It’s got a very strong anti-capitalist thing, class warfare, anti-corporate, anti-private enterprise, pro-distributed power, pro-distributed wealth, pro-distributed poverty.
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September 22nd, 2008 at 11:22 am
G.R.L. Cowan, hydrogen-to-boron convert said:
That might be a good way to address the existing legacy CO2 or it might be the ONLY way to do so that is effective, but I do not think it’s a reason to say we should keep using coal and we can just turn around and capture the Co2 in the atmosphere to balance the new CO2.
I think out first priority should be stopping putting any new CO2 into the atmosphere, or at least putting a lot less CO2 in the atmosphere – as little as we reasonably can. THEN we can think about maybe addressing atmospheric removal.
To me the idea you have has potential but it makes about a much sense as giving someone with a horrible bleeding wound a blood transfusion before you even bother bandaging up the wound and stopping the bleeding. What’s the point? It’ll just come out again if you don’t stop the problem. After you stop it then you can consider fixing the damage.
There is nothing clean about coal. It should be left in the ground.
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September 22nd, 2008 at 12:32 pm
Yes, coal burning must stop.
If we don’t have access to the wound, but do have access to a blood vessel we can use for the transfusion, then the analogy becomes accurate. We won’t refuse to save the patient just because we cannot use the method we would prefer. Or anyway, we shouldn’t.
Has coal burning stopped yet? My recommendation to that effect is several minutes old!
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September 22nd, 2008 at 12:37 pm
Oops, I didn’t realize the blockquote tag would do that. The words I quoted were Dave G’s, not mine.
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September 23rd, 2008 at 12:57 am
The reason that I am so wary about this whole “clean coal” program, is that even though it seems like a bad idea on so many levels I am afraid that it will gain some sympathic ears who hold influential political offices. Then the whole program gets billions of dollars of taxpayer money wasted on it because all of the subsidies that would be required to keep the program as well as any FutureGen facilities up and running. Eventually, the whole thing will become so entrenched, that any future politician who tries to dismantle it would be committing political suicide.
Sure it does not work, but since when has that ever stopped anybody from throwing money at it? Look at ethanol! The whole “ethanol economy” is clearly unworkable, yet record levels of subsidies go to biofuels every year, even if they are produced at a net energy loss. Any politician who threatened to end the ethanol program would soon find himself confronting an angry mob of agricultural producers who have set up large portions to of company strategy towards mining ethanol subsidies. Rural voters in farming communities would also be greatly upset, because if their ethanol subsides were cut off they would think it is a sign of “The Man” keeping them down and vote accordingly. Solar and wind power are both ill-conceived and impractical energy sources for baseload generation, governments around the world STILL dump money into keeping them afloat.
I apologize for this lengthy post, but it often seems like where energy production is concerned, the more idiotic the idea, the more financial and governmental support it will probably get. “Clean coal” might be the next ethanol disaster. I sure hope not.
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