PUMPING CO2 INTO THE GROUND

You know the geology - will it work? Will it stay where it's put?

Thats what the research proposals are trying to find out Lk. I know that the DOE, The U of Wyoming, and the Polish EPA are working on the studies at coal mines, and saline ground water bodies. Theoretically, at the temperatures and pressures involved at 2-3 kilometer depths, CO2 should be a solid .

So, how do you feel about subducting nuclear waste into trench systems? Is this more or less risky than that? Is that still on the table? Hmmmm, or did I just make that concept up (it's been so long since I think I reas that)....?

Farmer,

I am not familiar with the unit "Kk", can you enlighten me?
Also, what energy source would be used to isolate the CO2, pressurize, and pump it below ground? Would the emissions from this process negate the effects of disposing of the CO2 by this method (not to mention the energy needed to extract any methane generated)?

Would it be simpler to pump the CO2 into the oceanic abyss where the pressure and temp are conducive to dissolving it thereby affecting a "carbon dioxide" sink in the ocean?

JM

littelk,

I see no problem with burying nuclear waste in a trench. The problem has always been where the trench is. The Yucca Mountain project in Nevada has for years suffered from the "Not in my backyard!" problem. The disposal problem has always been one of nuclear energy's Achille's Heel issues.

JM

Jim-Sorry, (states with embarassment) Im not sure what Kk is except Kilokelvin , I meant kM (kilometers) Ive gotta learn to use the spell check routinely.
As far as the research for storing (actually sequestering) the CO2. Nobody wanted to offer demo funds for sending CO2 to the deep oceans because , well, we just dont know enough about what will happen. the same goes for nuclear wastes. We dont yet understand the propogation of the deep ocean subduction zones because noone has yet drilled them out. This may be academic in the near future, Im sure that some research lab like Lawrence Livermore will join together with scripps or woods Hole to do deep subduction drilling.

The CO2 , as far as I know would be liquified under pressure (I cannot recall what the

phase diagram of CO2 looks like under P/T conditions)

If wed pump CO2 into coal seams at .8 to 1.6 KM. The CO2 adsorbs onto the coal and CH4 is released. the neat thing with coal is that cO2 closes the fracture storage areas but other associated coalfield gases , like N , actually open the fractures and enhance the storage areas.

LittleK-Im not a big fan of dumping our crap into subduction zones until we learn more about their structures and how fast subduction occurs (we estimate it at about 4 cm /yr) All subduction zones dip TOWARD the continents, not away from them. Also , all subduction zones are associated with cascade type volcanic fields. These volcanoes are particularly nasty explosive types that are always moving about the suture line due to a number of factors that we dont understand well enough to begin using the areas for trash disposal. I know this was very popular as a concept in the 80s but then, people started listing what we know and what were the risks and the risks outnumbered the "what we knows"

Farmer,

Thanks, I suspected as much but thought it was a distance unit that I perhaps was unfamiliar. I remember the first time I encountered the term "hectare" I believed it was a misspelling of acre, I was wrong.

JM

Assuming that any appreciable amounts of CO2 could be harvested from the atmosphere in this way, it would need to be extracted either through fractional distillation of air, or chemical absorption using materials such as sodium hydroxide or lime.

Fractional distillation of large quantities of air, i.e. on a global scale, would be prohibitively expensive.

Lime is generated by heating limestone to drive off Carbon Dioxide - the very thing you are trying to collect using the lime! So there is no net benefit. Other alkalies can absorb CO2, releasing it by the addition of acids. Again, prohibitively expensive to process such chemicals on a massive global scale.

Perhaps it would be easier and cheaper to plant a lot more vegetation to absorb the increased CO2 levels?

Perhaps leaving CO2 levels as they are will help stave off the next ice age for a bit longer? Given that over geologic time scales, CO2 is continually diminishing and over millions of years may become too low to support vegetation at all, I say eliminate ozone depleters but keep the CO2!

...following

Kevin. The purpose of the Polish and DOE research is not to take atmospheric CO2, but to collect and compress CO2 at SOURCES, like power plants and pump this underground. The oceans are the best CO2 sink for disperesed atmospheric CO2, it gets incorporated into the ocean column and into CaCO3(as you said about making lime from limestone) However, an almost equivalent amt is released from the oceans.
CO2 sequestering is just a new way of capturing, compressing, and pumpingthis greenhouse gas to get it out of the system.

farmer,

It seems the question must be asked: At what efficacious point can one effectively and economically extract CO2 and deposit it into a "sink". Most "SOURCES" are envisioned where the CO2 is in gaseous form (witness your example of power plants). This is not different than atmospheric gaseous CO2. The problem, of course is chemically "locking up" the CO2 that is in the form of gas, thus Kevin's point.

Life forms lock up a lot of CO2 and prevent its deposition into the atmosphere as a gas. All life forms are useful but shellfish, diatoms (CaCO3) and plants; especially woody plants (containing both carbohydrates and cellulose) are excellent ways to lock the CO2 up for long periods of time (note: one only needs to lock up carbon and the same goal is reached). So, we can either encourage their reproduction and discourage their destruction via oxidation or we can employ their energy source to rid ourselves of the CO2... the Sun.

It is the energy from outside our "closed" global system that seems to be the key to solving the CO2 regulation problem and not the chemical method of sequestration itself.

JM

james-
The worldwide, manmade(from fossil fuel combustion) sources of CO2 generate an additional 7 billion tons per year. This is above all natural sources (according to the 2001 DOE repts). CO2 can easily be liquified and sequestered.By doing so its got a number of enviro pluses
1 Using it in nearly depleted oil wells is a means of secondary recovery besides long term storage,

2If its pumped into deep coal mines below the fractured zones, it can, by desorption, allow the release of methane which can be easily recoveredbesides storing the CO2

3It can be sequestered in ophiolitic and basic magma rocks. here the chemistry will allow the tie up of CO2 as carbonates by exchange of silicates, which woud be released as silane, a soluble form of sila liquid which sets like a gel.

4It can be stored in Salt domes and deep salts because these rocks act very plastically

The research is, like all research should, just looking at means and feasibility. The 7Billion tons , at best, can probably be reduced by source capture and sequestering , by only about 1/2 , or 3.5 billion tons. The March issue of geotimes (a geology trade magazine) had a propoganda article in it about CO2 sequestration because it will probably employ a whole slew of geology grad students down the pike.

CO2 is easy to capture and compress at sources, It can be liquified
and tanked or stored in pressure tanks. lots of "natural" spring waters like Poland Springs and Apollinaris, get their water from one place, and their (natural)CO2 from mines located elswhere, and they carbonate the water in a bottling plant, . Factories, power plants etc. natural sources account for an additional x billion tons and these are more dispersed.. Its interesting that, of the natural CO2 that the ocean takes up and plants transpire, there is an equal amt of loss in respiration when photosynthesis ceases .

One important point about sequestration, it has to be able to be stored and held for 500 or more years, with the idea that , by then, our successors will be out of the greenhouse gas business.

carbon dioxide sequestering
Hi,
I was surfing the net about CO2 sequestration in aquifers and came across this forum. Me and my friends just started on a project about CO2 sequestering in aquifers, we were wondering if any of you have any idea what is usually done when the aquifer temperature passes the critical temperature of CO2 ( which is about 31 deg.C) when there is no distinction between liquid and gas phase. As far as I know CO2 sequestering is also done in geothermal reservoirs where the temperature is pretty high. And also can you give some reference or any information about how the viscosity of the water changes when more CO2 is dissolved in water.
thanks a lot!

~Farmerman etall typed:~ Posted: Sat Apr 05, 2003 12:26 am Post subject: PUMPING CO2 INTO THE GROUND
Mankind generates 7 billion tons of carbon as CO2 a year, In order to drop the greenhouse gases by at least a third, novel science experiments by Polish Scientists and the US DOE are investigating collecting and pumping CO2 into saline aquifers at 2Kk depths or coal mines between 2.5 to 5.0Kk ft. depleted oil reservoirs, oil shales, and mafic ~not in my dictionary~ rock bodies. The depths planned are so that the P/T will render the CO2 stable as a solid or liquid and it can be mineralogically taken up ~does that mean removed by humans oe combined chemically with the rock as carbonates?~ in thousands of years (a geologic blink)

If it works, many new industries will be formed that can cash in on CO2 reserves (COs in coal mines can generate ~displace?~ methane by adsorption) . I think its worth funding, for our grandchildrens sake
littlek
Posted: Sat Apr 05, 2003 2:30 pm Post subject:

You know the geology - will it work? Will it stay where it's put? ~my guess is it will take more than a century for 1% to reach the surface from randomly selected sites~
That's what the research proposals are trying to find out Lk. I know that the DOE, The U of Wyoming, and the Polish EPA are working on the studies at coal mines, and saline ground water bodies. Theoretically, at the temperatures ~typically 350 degrees K?~ and pressures involved at 2-3 kilometer depths, CO2 should be a solid

littlek
Posted: Sat Apr 05, 2003 4:27 pm Post subject:
So, how do you feel about subducting nuclear waste into trench systems? Is this more or less risky than that? Is that still on the table? Hmmmm, or did I just make that concept up (it's been so long since I think I reas that)....?

JamesMorrison
Posted: Mon Apr 07, 2003 12:21 pm Post subject: er,

Also, what energy source would be used to isolate the CO2, pressurize, and pump it below ground? Would the emissions from this process negate the effects of disposing of the CO2 by this method (not to mention the energy needed to extract any methane generated)?
~I agree; the energy to get the CO 2 to a depth of 2KM in rock or 10 KM in ocean will likely exceed the energy from the recoverd methane the first century, so a net energy loss and a gain in CO2 is likely if the methane = CH4 is burned~
Would it be simpler to pump the CO2 into the oceanic abyss where the pressure and temp are conducive to dissolving it thereby affecting a "carbon dioxide" sink in the ocean? ~i understand this is also a pilot program in progress~

JamesMorrison
littelk,
I see no problem with burying nuclear waste in a trench. The problem has always been where the trench is. The Yucca Mountain project in Nevada has for years suffered from the "Not in my backyard!" problem. The disposal problem has always been one of nuclear energy's achille's Heel issues.
farmerman.
As far as the research for storing (actually sequestering) the CO2. Nobody wanted to offer demo funds ~they are afraid of lawsuits/lawyer, boo hiss~ for sending CO2 to the deep oceans because , well, we just don't know enough about what will happen. the same goes for nuclear wastes. We don't yet understand the propagation of the deep ocean subduction zones because no one has yet drilled them out. This may be academic in the near future, I'm sure that some research lab like Lawrence Livermore will join together with scripps or woods Hole to do deep subduction drilling.

The CO2 , as far as I know would be liquified under pressure (I cannot recall what the

phase diagram of CO2 looks like under P/T conditions)

If we pump CO2 into coal seams at .8 to 1.6 KM. The CO2 adsorbs onto the coal and CH4 is released. the neat thing with coal is that cO2 closes the fracture storage areas but other associated coalfield gases , like N , actually open the fractures and enhance the storage areas. ~is that good or bad?~
LittleK-Im not a big fan of dumping our crap into subduction zones until we learn more about their structures and how fast subduction occurs (we estimate ~but most are 2000 KM from a continent = 50,000,000 Years?~ it at about 4 cm /yr) All subduction zones dip TOWARD the continents, not away from them. Also , all subduction zones are associated with cascade type volcanic fields. These volcanoes are particularly nasty explosive types that are always moving about the suture line due to a number of factors that we don't understand well enough to begin using the areas for trash disposal. I know this was very popular as a concept in the 80s but then, people started listing what we know and what were the risks and the risks outnumbered the "what we knows ~high level radio active waste spewing from a volcano would be bad. Is the probability even one per million per million years at randomly selecteted subduction zone locations. In a million years the high level waste will typically be low level? Neil?~

neil-Im a little confused. I guess you were sort of quoting somee of us in this past discussion. I see various questions and maybe if we explore them in smaller chunks. Remember, Im an old guy who aint as fast on the uptake as I used to be.

What percent of that 7 billion tons of carbon as CO2 is produced in large facilities such as power plants (where it would be practical to collect it and compress it), and what percentage is from small producers (your car, lawnmower, home furnace etc) where it would not be practical to collect it?

That could have a lot to do with the cost benefit relationship, Jim. I was wondering, too.

Farmerman
Can you tell us anything about the natural gas that's going back in the ground in alaska? My skimpy knowledge about it, I heard there's enough going back into the ground every day to light up Calif. for a week.

Here are some "back of the envelope" type calculations. Please understand that everything here is an estimate or approximation.

Some reservoirs produce mainly gas, some a combination of oil and gas, and some mostly oil. Production engineers express this as the "GOR", or "gas to oil ratio". In the Field I work in, the value is roughly 700 - we produce 350 million standard cubic feet (SCF) of gas along with 500,000 barrels per day (BPD) of oil.

I haven't seen the values for the Alaska North Slope (ANS) for a long time, but 800,000 BPD of oil at a GOR of 500 probably wouldn't be too far off the mark. That translates to 400 million SCF of gas a day.

I'm trying to remember how much gas we used for heating and cooking when we lived in Texas. The best I can come up with is about 1700 SCF a day. If this is anywhere near close, then the ANS gas that is currently re-injected into the oil reservoir would serve about 235,000 homes.

There are a few alternatives to disposing of the produced gas through re-injection. There have been proposals to build a 800 mile gas pipeline parallel to the crude oil pipeline to Valdez harbor. The gas would then be chilled to -260 F to liquify it(LNG), and would be shipped to the lower 48 in specialty tankers. Another proposal is to build a 5000 mile long pipeline from ANS through Canada to the lower 48. The third, more intriguing proposal is to build a synfuels plant at ANS, turn the gas into a synthetic liquid, and send it through the existing crude oil pipeline in batch flow. Unfortunately, the economics do not allow for any of these options. (though I can't help but think that for the 80 billion we spent in Iraq we could have built a lot of pipelines, synfuel plants, and LNG tankers).

Hope this helps.