From the American Chemical Society , an environmentalist’s nightmare.
Desalination of drinking water, fracking, and methane hydrates all wrapped up into one positive outcome.
Using a form of ‘ice that burns’ to make potable water from oil and gas production
In the midst of an intensifying global water crisis, scientists are reporting development of a more economical way to use one form of the “ice that burns” to turn very salty wastewater from fracking and other oil and gas production methods into water for drinking and irrigation. The study on the method, which removes more than 90 percent of the salt, appears in the journal ACS Sustainable Chemistry & Engineering.
Yongkoo Seol and Jong-Ho Cha explain that salty wastewater is a byproduct of oil and gas production, including hydraulic fracturing, or fracking. These methods use water and produce as a byproduct almost 10 barrels of salty water for every barrel of oil. That water could help people in water-stressed regions. But it can’t be desalinated economically with traditional methods. Seol and Cha knew that an alternative called “gas hydrate desalination” showed promise. A gas hydrate consists of only water and a gas such as methane, the stuff of natural gas. Thus, when hydrates form, salts and other impurities are left behind. When the hydrate breaks down, the gas and pure water are released. However, forming the gas hydrate used in desalination required costly chilling of the water to 28 degrees Fahrenheit. Seol and Cha sought to develop a less costly version of the method, which involves a variation on methane hydrates, chunks of ice retrieved from deep below the sea that burst into flame when brought to the surface.
They describe development and laboratory testing of a new type of gas hydrate desalination technique. They formed the hydrates from water and carbon dioxide with the gases cyclopentane and cyclohexane, which made the method work more efficiently. It removed more than 90 percent of the salt compared to 70 percent with the previous gas hydrate technique. And the process works at near-room temperature, reducing the need for chilling.
The authors acknowledge funding from the U.S. Department of Energy’s National Energy Technology Laboratory.
The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 163,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.
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Wow! a process that combines natural gas (from fracked wells) plus evil CO2 (from the atmosphere) to turn fracking fluids into clean drinking water! And the natural gas is then released for use as clean energy. Perfect!
Take away Al Gore’s Nobel Prize and give it to these guys.
Desalination of drinking water, fracking, and methane hydrates all wrapped up into one positive outcome.
And, just for an added bonus, they use CO2 to improve the desalination at room temperature.
Interesting piece of chemistry, but I believe they are using cyclopentane or cyclohexane instead of methane, LH. Alternatives would be to use deepwell to extract brine for the fracking fluid and return it or return the fracking brine to fresh water with something like reverse osmosis if the fresh water is in short supply. In any event, it all sounds like quite an added cost.
Watch this issue get hushed up, bribed off and sent down the memory hole. This can not be in the true interests of the powers that be.
I’m waiting for the “Oh, but” people to show up. This news is just waiting to be rationalized into plausible unreality.
Very interesting! With a 90% desalination rate, produced water from many reservoirs would still be too salty for surface discharge (in my area of operation in OK at least). Typically the formation water I encounter is 100,000-135,000 ppm.
Cyclohexane (b.p. 81 C) and cyclopentane (b.p. 49 C) are both liquids at room temperature, not gases.
Looking at the paper, the hydrate is made at elevated pressure (3.1 MP = 31 bars), and cold (-4.5 C) temperature. Apparently hydrate formation becomes more efficient when there are two guest molecules, one larger and one smaller. The hydrates take a different structure depending on the guest, and with two guest molecules the hydrate structure includes two different-sized ice chambers. The two molecules in this case are CO2 and one of the cyclanes. The hydrate unit contains four CO2 molecules stacked 2 over 2, flanked on each side by a cyclane molecule.
They don’t burn the ice to get the water. The hydrate, once formed, is stable all the way to 16 C. Almost Ice IX. 🙂 So, the way it works is they make the hydrate using contaminated process water, filter the gas hydrate away from the process impurities, and then liberate the water by warming the hydrate past 16 C. The guest molecules escape and are recovered for re-use.
The remaining problem is that the recovered water is saturated in cyclopentane or cyclohexane, which makes it non-potable. Getting drinkable water requires distillation or reverse osmosis.
Still, it’s a big improvement, potentially anyway. Pilot plant studies are required to know for sure.
I had no idea that so much process water is produced by oil production, though. Reading the paper, apparently lots of ingenious ways exist for dealing with it on land. At sea, it’s apparently just discharged. Marine bacteria would have no problem dealing with the dissolved organics in discharged process water, but fish may not like the discharge area.
I’m confused about the statement “10 barrels of salty water for every barrel of oil”. My wife is originally from northern Pennsylvania, which has been ground zero for natural gas exploration via fracking. I see the wells and catchment ponds for drilling fluids everytime we visit her family. As I understand it, water and additives are injected into the borehole to fracture the rock and then pumped out at which point the well is connected to the gas pipeline grid. I’ve seen no physical evidence that water comes from these wells during the actually production of gas and nothing has been written about it in the anti-fracking local press either. Perhaps oil wells are done differently but at the outset it seems that the proceses would be nearly identical.
Dave: water is almost always produced with oil and gas. The formation needs to be water wet, to produce effectively. I know some oil wells in fields with water injection, that produce 95% water, and 5% oil.This is not water from fracing, but native formation water or the injected water. It will be about 3% salt.
Most oil wells have water separation at the well site, or at the battery where a number of wells flow to.
The water is usually recycled and re-injected.
Please, please, please. Take it from an industry insider, and one whose Master’s Thesis was on hydraulic fracturing, it is ‘fracing’ and not ‘fracking’. If you must, use an apostrophe, thus: frac’ing.
An interesting approach, but quite impractical in the field. Cyclo-hexane and cyclo-pentane are a bit pricy. Cyclo-hexane runs $4.29/gal, $1500/Ton. It makes me think of using tuna and crab as bait for flounder and catfish.
Out in the field, we have copius amounts of light hydrocarbons along with the salty formation fluid. Those light HC’s are near worthless at the well head in some places and are flared. It makes more sense to desalinate with the methane you can’t send to market anyway.
Now if there was a way to employ the available light HC’s in an energy and cost efficient hydrate-desalinization process, and discharge irrigation quality water to the nearby farms, that would be a win-win for a lot of folks.
Apparently there is some water used to develop the wells, some is in the formation, and some is injected to coax the oil or gas out? Would someone from the industry do a quick summary?
Les: there are a great many reservoirs that produce zero water and most certainly do not need to be water wet to produce effectively, quite the opposite. Basic geology tells us that when production is dependent upon structure water indicates little to no oil and gas present (gas on top, then oil, then water). Nearly all old traditional fields produce little to no water, the technology to deal with large amounts of water only really became commonplace in the mid to late 90’s.
That is not to say that very large amounts of oil and gas have not been produced from water wet zones, but this is a relatively recent development.
Some say the world with end in fire,
Some say in ice.
From what I tasted of desire
I hold with those who favor fire.
But if I had to perish twice
I think I know enough of hate
To say that for destruction ice
Is also great
And will suffice.
Robert Frost
Ten barrels of water per barrel of oil produced? If that’s what they are using then they are idiots. The actual numbers are about a hundredth of that, about 0.1 to 0.5 bbl water per bbl oil … they are also recycling more and more of the water.
w.
Chris4692:
Some water is used in the drilling process – a small amount
Some reservoirs produce water, some don’t – amount varies
In the post-drilling completion phase frac jobs use water, the amount can range from a few hundred barrels to hundreds of thousands of barrels. Water can also be used as a drive mechanism to flush hydrocarbons upwardly in a formation structure in a process used as water flood.
Very general explantion.
BTW I quoted the Frost poem because I like it and was reminded by the “ice that burns” mental image. Don’t read anything more into it.
Willis Eschenbach: I’m sorry but your numbers are incorrect. I’ve worked on profitable wells that produce over 5000 barrels of water a day for 50 barrels of oil and 500 MCF gas a day.
I may be an idiot, but my idiocy has made me lots and lots of money.
Tom G(ologist) says:
August 28, 2013 at 9:42 am
Please, please, please. Take it from an industry insider, and one whose Master’s Thesis was on hydraulic fracturing, it is ‘fracing’ and not ‘fracking’. If you must, use an apostrophe, thus: frac’ing.
Thank you for your interesting info, Tom, but if it is always spelled frack outside the industry, then it rhymes with crack, not with face. The word derives from fracture, which is pronounced like crack and has no k. This tells me why industry insiders omit the k, but their version will never catch on with the general public. Eventually, the public will win and the more practical fracking spelling will appear in industry articles as well. You might be able to get away with calling and spelling it fracting.
@Louis Hooffstetter says:
August 28, 2013 at 8:26 am
Unfortunately All the big guy Gore’s Nobel prize was for “Peace” – whatever that is. No science involved. And that about sums it up.
On the oil vs water arguments: There is obviously a very big difference between different wells and – in the interests of making their paper sound better – the authors used the worst case they could find.
I would be very very surprised if ALL oil was accompanied by 10x the volume of salty water (just think about the volumes involved for a moment and think about on-shore oil producing regions – is Texas really producing 10 x more water than oil in all of those nodding donkeys?), but maybe in some cases this is an accurate measure.
No, what these guys have done is develop a high temperature gas hydrate and are trying to get hold of oil company money (or, more probably, government money taken from oil companies in environmental clean-up “fees”) by a well-known route – invent a problem for your solution. De-salination is a very expensive way to get fresh water and really only needed in extreme cases so they are looking for a different role for their technology.
Tom G(ologist) says:
August 28, 2013 at 9:42 am
Like the wind that “bloweth where it listeth”, the English language goes its own way … and that way is rarely logical. As you imply, “fracking” is a shortening of “fracturing”, which doesn’t have a “k” in it anywhere … so?
The problem is that the pronunciation of “fracing” is unclear. Is it pronounced to rhyme with “racing”? And as a result, to clarify things, people put a “k” in it.
How many people? Well, here’s the results of the GoogleFight:
As you can see, you are outvoted by about 200 to 1.
Now you have a choice about that. You can get up on your soapbox and say that industry insiders spell it differently … or you can resign yourself to the idiocy of how the language actually works, accept that that battle was lost a while ago, and choose another battle to fight.
I suggest the latter for the sake of your blood pressure, because racing, erasing, fracing, bracing, and tracing don’t actually rhyme in most folks’ lexicon.
w.
I love it when two problems are combined to make a solution or two.
The use of cyclopentane (CC5) and/or cyclohexane (CC6) would be as a vehicle for the hydrate slurry. Water doesn’t dissolve in them. Methane hydrate is a solid up to 55° F, so you need a carrier to move it around. If it forms in gas pipelines it makes a plug, so methanol is added to tie up the water and keep the clathrate from forming. Methane hydrate forms naturally under pressure at temperatures below 55° whenever you mix water vapor and methane. Other gases also form hydrate clathrates (CO2, Argon, ethane, propane). Desalinating the water is a side benefit.
Put the chemical engineers to work developing a continuous process to form the solid from the gas/water mixture under pressure and collect/remove the hydrate. I would suggest starting with frothing the water under a pressured blanket of cool methane. The hydrate would settle in the water and could be collected centrifugally. The final process need not use the CC5 or CC6.
ATTENTION TROLLS:
“…salty wastewater is a by-product of oil and gas production, including hydraulic fracturing, or fracking.” (above article)
Probably an exercise in futility, but wanted to head off trolls’ screaming that the water being cleaned above was “an old man’s only drinking water!!! Poisoned! How will we survive??!!!”
******************
@ur momisugly Tom the Geologist — good for you to try to save the language from corruption. The others above are correct, though, the ‘frac’ing” cause is lost. I’ve tried to use it (per your correction) and it made ZERO impact on this site. If these careful scientists don’t care, no one will. Grit your teeth and (grrrrr) embrace “fracking.” Like Kleenex and “It was me,” it’s here to stay. Sorry about that, dear ally for truth. You sure can’t say you didn’t try.
“Kleenex” — should be lower case “k” — spell checker didn’t get the memo (still calls them tissues, I guess)