Prediction – greens still won’t be able to get past the word “coal”.
Researchers at MIT have shown the benefits of a new approach toward eliminating carbon-dioxide (CO2) emissions at coal-burning power plants.
Their system, called pressurized oxy-fuel combustion, provides a way of separating all of the carbon-dioxide emissions produced by the burning of coal, in the form of a concentrated, pressurized liquid stream. This allows for carbon dioxide sequestration: the liquid CO2 stream can be injected into geological formations deep enough to prevent their escape into the atmosphere.
Finding a practical way to sequester carbon emissions is considered critical to the mitigation of climate change while continuing to use fossil fuels, which currently account for more than 80 percent of energy production in the United States and more than 90 percent worldwide. CO2 emissions from fossil fuels are projected to rise by more than 50 percent worldwide by 2030.
It might seem paradoxical to reduce the carbon footprint of a coal plant by making its emissions into a more concentrated stream of carbon dioxide. But Ahmed Ghoniem, the Ronald C. Crane (1972) Professor of Mechanical Engineering and leader of the MIT team analyzing this new technology, explains: “this is the first step. Before you sequester, you have to concentrate and pressurize” the greenhouse gases. “You have to redesign the power plant so that it produces a pure stream of pressurized liquid carbon dioxide, to make it sequestration ready.”
There are various approaches to carbon capture and sequestration being developed and tested, and the oxy-fuel combustion system “is one of the technologies that should be looked at,” says Barbara Freese, lead author of a report on coal power by the environmental group Union of Concerned Scientists. Ghoniem says that of the approaches to oxy-fuel combustion, he and his MIT colleagues are the only academic team examining a pressurized combustion system for carbon dioxide capture.
A paper describing the approach appeared in August in the journal Energy. The Italian energy company ENEL, the sponsor of the research, plans to build a pilot plant in Italy using the technology in the next few years.
Ghoniem explains that any system for separating and concentrating the carbon dioxide from a power plant reduces the efficiency of the plant by about a third. That means that it takes more fuel to provide the same amount of electricity. Therefore, finding ways to minimize that loss of efficiency is key to making carbon-sequestration systems commercially viable.
Reducing the penalty
There will always be some energy penalty to such capture-enabled systems, because it requires some energy to separate gases that are mixed together, such as separating carbon dioxide from the combustion gases emerging from an air-based combustion chamber or oxygen from air for oxy-fuel combustion. As an analogy, “mixing salt and pepper is very easy, but separating them takes energy,” he says. “Nobody in their right mind will jump into this and do it unless we can reduce the energy penalty and the extra cost, and only if it is mandated to reduce CO2 emissions” he says. And that’s what the new process is designed to do.
Other groups have been looking into oxy-fuel combustion, in which pure oxygen is fed into the combustion chamber to produce a cleaner and more concentrated emissions stream (a mixture of oxygen and CO2 replaces ordinary air for combustion, which is nearly 79 percent nitrogen and 21 percent oxygen, thus eliminating more than three-quarters of the resulting flue gases). The focus of their studies is a system that adds one more element, putting the whole combustion chamber under pressure, which results in a more concentrated, pressurized emissions output.
Ghoniem says even though this process uses more energy at the beginning of the combustion cycle because of the need to separate oxygen from air and pressurize it, the increased efficiency of the power cycle raises the net output of the plant and reduces the compression work needed to deliver CO2 at the requisite state for sequestration, as compared to the unpressurized carbon-capture systems; in other words, the overall energy penalty is reduced. “You have to deliver carbon dioxide at high pressure for sequestration,” he points out. The system simply introduces some pressurization earlier in the process, so the output stream requires less compression at the end of the process while extracting more energy from the combustion gases.
The pressurization of the combustion system also reduces the size of the components and hence the plant, which could “reduce the footprint of needed real estate, and potentially the price of components,” he says. It is expected to lead to an overall improvement of about 3 percent in net efficiency compared to an unpressurized system, and with further research and development this can probably be improved to about a 10 to 15 percent net gain from the current values, he says.
That could be key to gaining acceptance for carbon capture and sequestration (CCS) as a way to allow the continued growth of coal power while curtailing its emissions. The Union of Concerned Scientists report last year, “Coal Power in a Warming World,” said: “CCS is still an emerging technology. It has the potential to substantially reduce CO2 emissions from coal plants, but it also faces many challenges.”
Freese says that “the potential of this technology is there, but it needs to be demonstrated” whether it can work as expected and be economically viable. “We want to see what these actual results are before committing” to implementing such systems. Also, she added, all carbon-sequestration plans “don’t solve all the other fuel-cycle problems — all the problems associated with mining.” In fact, because all such plants are inherently less efficient, “you’d need to mine more coal” for a given energy output.
The new MIT research has the potential to help narrow that gap, if it really does prove capable of reducing the efficiency penalty enough to make such plants competitive, and if the planned ENEL pilot plant in Italy based on this technology is successfully built and tested to confirm the practicality of the concept.
Ghoniem concedes that much more research is still needed for CCS technology. The three areas that need study most, he says, are systems’ integration to determine the operating conditions at which the different components work together for highest efficiency; component-level research to optimize of the design of individual parts of the new system, especially the combustion chamber; and process analysis to examine the details of the physics and chemistry involved. His group has been concentrating on detailed computer simulations of the process to aid in the design of better systems.
Other team members include graduate students James Hong and G. Chaudhry, Prof John Brisson, Randall Field from MITEI and Marco Gazzino from ENEL.
John Podesta is the man who hired “Green Jobs Czar” Van Jones a few days after he was forced to resign.
No word on what Van is actually going to do, other then continue milking the scam, of course.
It is a very common view amongst those who get paid from taxes (BBC being one). Unless a recession were very deep and continued for an extended period their income 9and pension) is secure. Their only view of the recession comes to them second hand. “What recession?” is a fair question if you are paid the same each month regardless. Even if the Government has to borrow the money it still appears in your Bank at the end of the month.
In my experience they are also a lot happier than the general population to punish “industry”. There is just no direct connection to their world.
This basic disconnect from industry and even economics 101 leads to this kind of thinking (from a different thread)
The belief seems to be that there is some kind of separation between “us” and the “fossil fuel industries”. Worse is the naive belief that “they” will suffer a “loss of income”. No concept of passing the increased production costs onto customers or of the results of those increased prices. Total disconnect, they are paid regardless and as far as they are concerned any disparity between their pay and rising prices will just have to be rectified somehow.
Perhaps something along these lines will get them re-connected? (sorry)
Smokey (06:22:52)
Thanks for the reminder. Why isn’t this taught in every relevant class?
Maybe it’s time for someone to repeat R. W. Wood’s experiment on a larger scale, with some variations (e.g. fill one rock-salt house with pure CO2, one with no CO2), and publicize it in advance and as conclusions come in.
I’m sure there are folks here who could design experiments that would anticipate any amount of nit-picking by Alarmists, and that would be dramatic enough to appeal to the media.
/Mr Lynn
This is not new. Pressurized combustion systems for large power plants were taught when I was in college in the early 1970’s. It sounds great in theory – but the practical problems are immense.
One of the greatest problems is injecting a solid fuel – coal – into the pressurized combustion chamber. For large coal lump sizes, one uses lock hoppers with pressure seals. Not a reliable design as these are plagued with failures. For finely ground coal powder, one could fluidize the powder with high pressure air (or in this case, oxygen) but run the risk of fire. A third alternative is to form a slurry of coal powder and a liquid then pump the slurry into the combustion chamber. None of these alternatives are cheap.
What they also do not mention is that the high-pressure CO2 exiting the combustion chamber is not pure, but has water vapor, sulfur oxides, and particulate matter. The stream of gases would be cooled to condense the water vapor into water. The resulting water would contain dissolved CO2 which would release when the pressure on the water is reduced – yielding a great fizzing of CO2 into the atmosphere.
This process needs a lot of development work, just like it did in the 1970’s.
There is no way such a plant can compete on cost or reliability with a combined cycle gas turbine plant using cheap, abundant, clean-burning natural gas.
No one is mentioning that when we sequester CO2 we actually sequester twice
as much Oxygen as Carbon; I guess that is ok, no one needs the Oxygen, right?
What a waste of money, effort, time and resources. Taking free aerial fertilizer for plants out of the air and burying it. With the implicit assumption that this trace-gas fertilizer controls the climate?
The post-modern age is well under way.
Ghoniem explains that any system for separating and concentrating the carbon dioxide from a power plant reduces the efficiency of the plant by about a third.
So we will need a thirty three percent increase in energy output to make up for it. Mind numbing stupidity by The Union of Concerned Scientists.
RE: Wood and greenhouses.
Water and ventilation (assisted for quick results) combined being probably the fastest (practical) way to cool things back down again and keep them that way.
Why it is almost as though that water cycle stuff has some purpose after all. Who knew?
No form of power generation is acceptable to the Greens.
They don’t want fossil fueled power because of CO2.
They don’t want nuclear power because of concerns over waste storage and possible radioactive leaks. ( Even though US nuclear power plants have an outstanding safety record.)
They don’t want windmills because they kill birds and spoil the view.
They don’t want solar because it would cover vast tracts of desert and and presumably destroy the habitat for desert dwelling critters.
We need a national debate on power generation. I propose we have it in January and that we shut off all forms of energy for one week; no gasoline, no coal fired power, no nuclear power, no natural gas. At the end of the week the nature of the debate will have improved dramatically and the green meanies will be shown the door.
Big oil is in America, Offshore. Kinda hard to carry picket signs and get on cameras in water
good point on sequestering O2 when we pump CO2 and the other point:
Plants that receive excess CO2 consume less water.
RE: MartinGAtkins (07:42:41) :
Ghoniem explains that any system for separating and concentrating the carbon dioxide from a power plant reduces the efficiency of the plant by about a third.
So we will need a thirty three percent increase in energy output to make up for it. Mind numbing stupidity by The Union of Concerned Scientists.
– No – we need a 50% increase in energy output to make up for it
– i.e. a 50% increase in energy costs…..
I don’t care how accurate that is, he’s going to have to find phrasing which sounds less dangerous. 🙂
And to the person that was worried about the heavy metals emissions, modern plants already try to stop that. That’s why they have piles of radioactive fly ash to dispose of, rather than the simpler disposal of belching black smoke.
Incidentally, I think a traditional coal fired plant should include belching black smoke. So the photo with white water vapor trickling out of the exhaust pipes (“smokestack” is not descriptive), and all the emissions equipment clustered between the boilers and exhaust, is of a modern plant rather than a traditional one. I wonder how hard it is for greens to find photos of U.S. smokestacks belching black smoke for their web sites; probably not hard if they steal them from each other.
Re: Wood and Greenhouses,
He did say then, that there was a temperature difference of 1C, but didn’t specify which was the warmest. Brilliant.
The problem with extrapolating this experiment is that we don’t know what happens to the absorbed (by glass) IR. Does it re-radiate back to the ground or does it just warm the glass? If it doesn’t reradiate, then it can’t be analogous to CO2. And if it does re-radiate, then it must add some warming. So I don’t think this is very helpful either. In any case, there are plenty of sealed flask type experiments that measure the re-radiation of CO2 very accurately, and it is real.
IMO, skeptic arguments that deny the reality that CO2 has a greenhouse forcing, or somehow violates the second law of thermodynamics, just exposes us to ridicule.
More exasperation for practical engineers. So most of the coal is burned in the northeastern quarter of the country (some in the west) and natural gas and oil are produced in the south and west – the reservoirs are a little separated. A fair amount of natural gas is now produced from coal seams which reduces the reservoir availability a bit. Also, I’m trying to envision how this sequestration will work outside the lab. CO2 is liquid, the critical temp is 31C (may be close to this at depth of oil and gas) and the critical pressure is 74bars (oil well about 1km deep is about 250 bars). The reservoirs contain fluids – remaining oil and gas, salt water, H2S in communicating pores. Someone walk me through the process: You have liquid CO2, you connect it up to a reservoir, assuming one is close at hand, and then what happens?
It looks like they found a way make the combustion more efficient – almost enough to make a plant with carbon capture competitive, so they say. If they can get a 10-15% improvement in the efficiency, or even the 5% they claim to have now, then maybe there is something useful here. Throw out the carbon capture part of the project and you’re left with more efficient combustion which would make all coal-based energy cleaner and cheaper.
Another thing – since water vapor is a “greenhouse gas”, why is there no talk of capturing the water? Power plants produce enough water vapor to produce significant clouds, and I have even seen snow fall from the clouds produced from a large power plant near Indiana, PA.
RE: “Traditional coal power plant – Image from USGS”
OMG … what a terrifying image! I can SEE the evil CO2 coming out of those stacks … see that white “smoke?” BAN IT!!! BAN IT ALL!!! /sarc
RE: “At a further penalty, it could be shipped to the South Pole and kept refrigerated under the ice by electricity from windmills.”
Right next to “The Blob!” – LOL!
Well, the day is getting shorter if you’re in the N.H. There’s time for you to do some building and testing before Spring approaches and it’s time to turn on the webcam. Hmm…salt… You can’t simply put your demonstration outdoors because of that rain thing which sometimes gets in the way of the sunlight.
I wonder where one gets rock salt material for such things. I see there are opaque salt blocks being sold for kitchen use, where it’s both “considered purest” and containing dozens of “beneficial trace minerals”. Looks like halite is the key search term for raw material, while “sodium chloride infrared window” finds the high quality stuff.
Just think how long it took for those lovely blue-green algae to bestow the benefits of free clean green renewable OXYGEN on planet earth, so we homo sapiens sapiens could evolve, and revel in it.
So now we have a bunch of idiots who want to go backwards, and tie up all that free clean green renewable Oxygen in rocks again.
These busibodies have rocks in their heads; that’s what they have.
Why don’t those MIT geniuses figure out how to recycle the CO2 to extract the oxygen from it and turn the carbon into fishing rods and golf clubs.
After all, they want to recycle water or hydrocarbons to get clean green HYDROGEN for the future energy revolution, so why not Oxygen as well.
We are living on a planet run by idiots.
If I reduce the efficiency of a coal fired power plant “by about a third”; based on my extensive mathematics credentials, my model suggests that I actually net about two thirds of the energy I used to get; and then applying a well known computer modelling AlGorythm I can deduce that in future extrapolation I would need to burn 50 percent more coal in the future, to obtain the same energy that I can get now.
That would mean I would run out of coal much sooner than previous models suggested, and I would have less future time to develop free green clean non-polluting infinite thermonuclear energy from the top 1/16th of an inch of San Francisco Bay.
It is NEVER an advantage to simultaneously raise costs, reduce efficiency, and increase resource depletion all at the same time. Follow that route, and we will all end up back in the trees gathering figs, like our ancestors used to do.
George E. Smith (10:15:24) :
Thanks for your wise words George but may I add the word “dangerous” to “idiots”.
I grew up during the Cold War and served with our Air Force.
The “dangerous idiots” in our Governments, our Scientific Institutions and our Mainstream Media pose a bigger threat to us than the Russians during the Cold War.
I have seen the best minds of my generation wasted on stupid ideas like carbon sequestration. Geez.
Just to reiterate: pressurized combustion of solid fuel is not going to happen. For gaseous or liquid fuels, yes, we do that already in gas turbines. But not for solid fuel like coal. The difficulties of feeding the solid fuel into a pressurized combustion chamber make this too unreliable and too costly.
The MIT proposal is much ado about nothing.
This article is a great example of burying bad news by keeping talking.
Gas compression is very energy intensive. Compressing CO2 to 80 bars takes many Megawatts. The article is correct when it says CCS thermal efficiency will be lower by about one third.
Not to miss the point, let’s just rephrase that:
– there will need to be a CCS coal plant for every two, just to operate the three CCS processes,
– or, another way, the three CCS plants will have the same net electrical output of two “conventional” stations, but will consume the same fuel as three “conventional” stations.
Research to improve efficiency by playing around with the point of compression, and hoping reduce real estate footprint by using smaller components ….. errr, yeah, right.
Beyond the substantial cost and lost efficiency…
Is it likely that sequestration will cause an earthquake. No one has ever sequestered a significant amount of CO2. What we do know is that an earthquake can be induced by pumping water into the ground. It happened near the Rocky Mountain Arsenal back in the 60’s. In 1962 they started pumping water into a well for the disposal of chemicals. Earthquake activity in the area increased soon after. They postponed the pumping for a while and the earthquake activity decreased. When pumping resumed, so did the earthquakes. Studies showed that the earthquake activity centered around the well.
I know that state governments have been approached with the liability question and they flat out said no way. There is too much political risk in taking on that responsibility.
An earthquake near a sequestration field would ruin any company without government protection…even if the earthquake was not triggered by CO2. We all know that truth and logic endangered ideas in American court rooms when tons of money is involved.
There are many hurdles for carbon sequestration. Personally, I think it is all a waste of time an money. I’m sure the MIT people working on this could accomplish great things. It’s a shame to see them waste their time and brain power on such nonsense.