Carbon Capture and Sequestration 8

[awhicker84]

Hi all,

Is there a forum on this community dealing with carbon capture and sequestration?

This is a huge potential industry and we need it. I'd like to read up on the current engineering problems and solutions.

Thanks and cheers,

 

[JAE]

Have you browsed the forum lists?

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[awhicker84]

Yes. Did I miss it?

 

[SlideRuleEra]

From search engine "Google Scholar": Carbon Capture and Sequestration

or the old-fashion way:

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[awhicker84]

Haha, I understand how to Google the words. I was wondering if there is any engineering forum / topic areas dedicated to it on this site. In my spare time, I will be attempting some carbon capture and sequestration.

 

[awhicker84]

Also, when fall arrives and your tree vacuum loses its leaves, CO2 is added back to the atmosphere. When your CO2 vacuuming tree dies, it most likely decomposes and also releases its CO2 back into the atmosphere.

Trees aren't a great solution for putting CO2 back into the ground, hence the interesting engineering problem of somehow getting CO2 out of the air and then keeping it out of the air.

 

[SlideRuleEra]

Well, I didn't intend the "tree" to be only a joke. There is serious investigation of large scale forest management for sequestration.

Anyway... on Eng-Tips, since 9 May 2000, there have been exactly 52 threads that include the words "carbon sequestration". So, doubt you will find much discussion here.

Perhaps you will want to read about the seven advanced "Carbon Capture Technology" projects the US Department of Energy announced (16 Feb 2018) that they will be funding.

or, Drax Electric Power Station project announcement (21 May 2018).

or, maybe the Petra Nova facility that began operation in January 2017. One of only two operating.

Another is the 110 MW Boundary Dam plant. The second operating station.

Kemper abandoned plans for capture in June 2017.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[JAE]

There may only be 52 threads so far but maybe because there isn't a specific forum for that topic.
On the other hand there are forums here that aren't that active either.

I've Ref Flagged your post and asked management to review your question.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[moltenmetal]

Carbon capture and sequestration is an "industry" only in the sense that it is being studied by people for money.

It is also, in my opinion, a dangerous distraction from what we really need to be doing, which is focusing on the elimination of the burning of fossils directly for energy.

A simple mass balance will explain why: just look at how much fossil carbon we're burning each year for energy right now, convert that all to CO2, and calculate a volume as a liquid. Now try to imagine finding a new hole that big, somewhere on earth, each and every year.

Any process which is going to store CO2 in a form other than as CO2 itself is going to require energy. That begs the obvious question: why not avoid wasting that energy and simply use whatever source you were planning to waste on converting CO2 to something else, into a means to replace the fossils we're currently burning? By so doing, you'll not only avoid the CO2 emissions, but also all the toxic emissions that inevitably come along with burning fossils!

Thermodynamics explains why the fact that CO2 is a desired combustion product, also necessarily makes it an undesirable feedstock for almost every chemical or material. A handful of highly oxidized species may make sense to make using CO2 as a feedstock, i.e. working backwards from a thermodynamic point of view- but it's quite a small handful, none of which would be reasonably consider to be a fuel. If you want a fuel, you'd be better off starting with literally ANY other form of carbon than CO2 or carbonate. Of course if we are going to ignore thermodynamics, we should simply convert all the CO2 to diamonds and oxygen and go have a beer.

Once we've stopped burning fossils for energy directly- hopefully in the next 50 years- we can start talking about processes to enhance the rate at which nature takes CO2 back out of the atmosphere.

The limited natural capacity we have for storing CO2 as a gas, we'll need just to satisfy our desire to keep roasting carbonate rocks to make cement etc.

 

[epoisses_]

Plus the atmosphere would run out of oxygen. I don't see any better solution for the surplus CO2 other than photosynthesize it all back, whether we have the trees do it or whether we help them somehow.

 

[awhicker84]

Moltenmetal,

We need both CO2-less energy and carbon capture. I think it will be an entire menu of options if we want to solve the global warming problem.

There are people focusing on how to capture all the CO2 exiting power plants.

Unfortunately, even if we stop producing all CO2 today (or capture it 100%), the earth will still go thru a big warming cycle. If we continue as business as usual for 50 more years, we're possibly dooming ourselves to either barely surviving as a species to possibly not surviving at all. I think it is estimated that a business as usual would be an increase of 4 C by year 2100. We're melting permafrost and glaciers and acidifying oceans with 1 C increase. It's not going to be pretty.

Scientists agree that the polar bear is already extinct and coral reefs are doomed, for example. Ocean acidification is going to cause huge problems. Droughts are getting worse (Syria civil war, California wildfires). Sea levels will rise. At some point methane release from permafrost and the antarctic ice sheet will cause a strong negative feedback loop that we may have a really hard time stopping, even while taking CO2 out of the atmosphere.

At this point, we need more than stopping CO2 production, we need negative CO2 production.

We're working with microbes to see if we can create carbonate -> calcium carbonate (limestone). As far as I know, the big companies are using chemistry (which is probably smarter, but microbes are so cool). Biggest challenge is (obviously) making a process that is a net CO2 negative. The companies right now are producing a product instead of burying the CO2. One company makes rocks to replace gravel, I think. It doesn't really matter as long as the CO2 stays out of the atmosphere.

We took stuff out of holes, we can put it back in.


Slide Rule Era,

That's interesting. I'm going to take a look. I did hear about farming techniques that could help pump CO2 back into the ground via plants. Maybe this is similar?


Cheers,

 

[lacajun]

Ion Engineering, Boulder, CO

They've been at it for 10 years now.

Pamela K. Quillin, P.E.
Quillin Engineering, LLC
NSPE-CO, Central Chapter
Dinner program:

http://nspe-co.org/events.php

 

[GregLocock]

Much as I like trees they are a con when it comes to carbon capture. They live for a few hundred years at most (and as a commercial venture more like 50) at which point all the CO2 they have sequestred is temporarily stored as wood or paper, or released immediately back into the atmosphere as it decomposes.

Cheers

Greg Locock


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[SlideRuleEra]

Permanent reforestation of large areas where trees were removed years ago is where the interest in carbon capture and storage is centered. I agree, trees come and go, forests have long term potential. The potential benefit is modest, but can be done. Here is one paper: "Carbon Capture and Storage in Forests".

Trees... forests... these are "small potatoes". The big push for carbon capture and storage is for coal-fired electric generating stations. I'm a novice reading about carbon capture/storage, but do have a fair amount of first-hand experience with design, construction, (and to a limited extent) operation of coal-fueled electric generating stations in the USA.

As a fuel for the future, coal is GONE, and it has nothing to do with technology, politics or the environment. The economics for coal vanished about 15 or 20 years ago with low cost natural gas becoming available.

1) The best coal plants are about 34% Correction: 47% + (thermally) efficient. A combined cycle natural gas is at least 50% efficient... over 60% can be done.

2) A modern coal plant would cost (if any were to be built) about $2 to $3 million per megawatt of gross generating capacity. A natural gas plant, about $1 million per megawatt.

3) Natural gas burns cleaner than coal. A modern coal plant has a precipitator for fly-ash removal, scrubber (flu gas desulfurization) to remove sulfur compounds, SCRs (selective catalytic reactors) to remove nitrogen compounds. This equipment consumes a lot of electric power (parasitic losses). Current technology for carbon removal requires even more power. For reference, a coal plant has about 10% total parasitic loss (e.g. a typical existing, modern 600 MW plant uses about 60 MW for it's own operation). Natural gas avoids much of this environmental equipment with reduced parasitic loss.

See Scientific American, "Will the U.S. Ever Build Another Big Coal Plant?"

http://www.SlideRuleEra.net

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[awhicker84]

Thanks!

I'll give it a look.

 

[ScottyUK]

SRE - the big ultra supercritical coal stations are currently achieving efficiencies in the mid to high 40's. 50% thermal efficiency isn't too far away. 34% was being achieved 40 years ago.

Low-cost gas will be short-lived, the North Sea being a great example of how to waste a reserve of clean, easily controllable fuel capable of supplying domestic and commercial for centuries by burning it in just thirty years in utility-scale power plants. One of those CCGT's paid my mortgage for ten years, but it was still a short-sighted energy policy. I think coal might rise again to fill the gap if nuclear new-build remains massively expensive.

Will nuclear fusion ever make it from prototype into commercial operation? And if it does - what will the cost be, and will it be worth it if it is clean?

 

[SlideRuleEra]

Thanks, Scotty, I stand corrected.

I don't know about a coal revival in the US, we burned low sulfur coal from eastern Kentucky, hauled on unit trains, but much of it in other places is "dirty" lignite.

Hope fusion comes along, for the last 60 years it has always been "10 years away". Things do seen a little different now.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[RickyTickyTavi]

Also keep in mind, that while yes when a tree dies, part of its carbon re-enters the atmosphere, but other portions are sequestered by other organisms as part of the carbon cycle, and a percentage are sequestered by none other than the soil, which over millions of years turns it back into hydrocarbons for us to burn. Even if that value is less than 1 percent, planting forests is an easy, relatively cheap, and there are secondary and tertiary benefits aside from just carbon sequestration.

 

[miningman]

I think Scottys comments re North Sea Gas are extremely valid but I also think that on a global scale it is too easy to be influenced by local knowledge. There are absolutely massive reserves of gas in Western Canada, and the only reason why it is not being exported to Japan today is political and environmental objections to pipeline construction. I believe the Aussies have already stepped up to take advantage of the opportunity.... liquified NG is already a huge global trade.

I also believe that coal will have its day again , but not as a conventional thermal fuel. The technology exists today to gasify coal... yes its still a fossil, carbon based fuel but it eliminates the sulphur problem. With further R+ D I believe we will have no choice eventually....theres so much of the stuff still available and all the renewables will not be on line in a timely manner.

And to me, trapping the CO2 ultimately as Calcium Carbonate makes sense, altho Im not sure if thermodynamics or entropy of the chemistry makes sense. Equally Ive never understood the basic energy aspects of compressing CO2 and pumping back underground somehow. Compressed air is such a inefficient method of energy transmission. where are the net gains coming from. Or is this another boondoggle being foisted on the ultimate consumer.

 

[moltenmetal]

awhicker84: given that we continue with the profligate combustion of fossils for energy, if we need to not only stop using fossils for energy but actually actively sequester atmospheric CO2 at the same time to avoid global catastrophe, you're basically saying we're screwed. There is no feasible way to store the amount of CO2 we're dumping each year, and I'm confident that we won't be inventing one any time soon either for the reasons previously mentioned in my post. Those are reasons of thermodynamics and elementary mass balance, so they're rather hard to argue against.

Again, the entire focus on CCS in past has been to allow us to continue burning fossils, without the AGW guilt- and to me, that is totally counterproductive. It's merely a way to piss through our finite, precious fossil resources even faster, because a substantial fraction of the produced energy will be needed to separate the CO2 and store it - assuming we have somewhere to store it. And if the means to store it involves converting it into something other than CO2 after the CO2 has been produced, the net energy generation will be NEGATIVE- thermodynamics virtually ensures that.

We need those fossil resources to use as chemical feedstocks. In comparison to the challenge of replacing our fossil feedstocks with renewable-sourced materials, the challenge of replacing our fossil energy use with low emission alternatives like renewables and nuclear is actually pretty easy- it's just a matter of money and political will. It doesn't even require any new inventions, although new inventions that will help are inevitable as they are being made every day.

It's a different matter to consider coking fossils to strip them of their hydrogen for energy, burying the resulting coke rather than burning it. That is in fact thermodynamically possible for everything other than coal. This approach is being seriously considered for biofuels production such that the biofuels become truly CO2 negative. Regrettably, since biofuels can't make money competing with fossils without subsidy or mandates or both, even IF they burn the char for energy, you're talking about very, very expensive energy in that case.