Carbon Dioxide surface sequestration with alkaline earth silicates: A response to G.R.L. Cowan.

A couple of weeks ago I posted a comment in response to this post by Rod Adams on the Atomic Insights Blog:

http://atomicinsights.blogspot.com/2008/10/comparing-scale-of-used-nuclear-fuel-to.html

The next comment on the thread was from G.R.L. Cowan, who denied that CO2 sequestration was a pipedream, and proposed that excess CO2 can be neatly sequestered by reacting it with crushed alkaline earth silicates, such as olivine and serpentine. There was something of a debate on that thread which I shan’t recapitulate here. I did not participate, as my knowledge of the field was inadequate for me to do so. Nonetheless it was an intriguing proposition, and I have been considering it ever since. I was actually inspired to get in touch with an old friend who I have not contacted for many years to get his input. He holds a doctorate in chemistry, although he hastens to add that his field of specialisation is polymer chemistry and he is unwilling to declare confidently one way or the other on the practicality of this proposal. He did state that he considers the term ‘clean coal’ an oxymoron, and shares my opinion that the ideal carbon sequestration strategy is to leave the coal where it is in the first place, but he also concedes that the chemistry for alkaline earth silicate sequestration does work, although we might question the economics. Here following is the email he sent me in reply, which he has graciously permitted me to quote:

Ahoy Finrod, An interesting ramble which covers many possibilities, but facts are more difficult especially since so much is at its infancy. A perfunctory glance at the net shows the chemistry is well known i.e. it is scientifically established process. However, while the thermodynamics may be favourable, evidently the kinetics are not so much so. In other words, while the overall journey may be downhill, it is uphill for at least part of the way. Getting over the activation hump is the key and there are 2 main ways to achieve this: a) wait for long enough - scatter the stuff around and walk away in expectation it will do its thing eventually. Grinding it up finely is one way to accelerate the process - after all these rocks have been sitting around for millions of years. If not for this activation energy I would expect life could be quite startling as rocks randomly exploded around us, especially if we breathed on them. b) force the issue using e.g. heat/catalysis as discussed in article below (which I selected more or less randomly). This all involves more inputs. So while thermodynamics may rule, kinetics will dictate when this will happen. I am not sufficiently knowledgeable to say if and when this process would become viable, but as we discussed on the phone, there is a hell of a lot of work and machinery involved in locating and crushing all these rocks....and all of this is consuming other resources and generating other byproducts. And are there other side effects of all the dust and carbonates we are generating in the process? CO2 is not our sole enemy.

The ‘article below’ referred to is:

Making rocks
Nature has the best track record for sequestering carbon dioxide from the air into the ground, through the process of weathering. Carbon dioxide is slightly acidic and as it reacts with rocks and soil, it converts into other chemical forms. The only problem in putting nature to work on carbon sequestration is that the process takes too long by human standards. In order to help limit the amount of carbon dioxide in the atmosphere, some geologists are looking to speed the weathering process up through industrial means — converting carbon dioxide into carbonate rocks.“We end up making rocks,” says Klaus Lackner of the Earth Engineering Center at Columbia University. But they have to start with rocks first. To do so, they use magnesium silicates, a class of peridotite rocks that include serpentine and olivine. Exposing magnesium silicate to an aqueous solution of the slightly acidic carbon dioxide forms carbonate and silicate, such as sand. Presto-chango, the carbon dioxide is gone and new carbonates and silicates have replaced the original rock. And the process is exothermic, producing heat. “So its thermodynamics are downhill, it happens spontaneously,” Lackner explains. This is why weathering in nature also occurs over time. So why aren’t we mass-producing carbonate rocks with our abundance of carbon dioxide? Again, time is the limiting factor. The world has an abundance of magnesium silicate rocks, but reacting those rocks with only carbon dioxide is a slow process. “We are trying to take the process and accelerate it for an industrial setting,” Lackner says. In order to speed the reaction up, a stronger acid is also needed and, in some cases, additional heat. The Albany Research Center in Oregon, and Ohio State University, are both working on building cost-efficient methods. Ultimately, achieving large-scale sequestration will mean building power plants at magnesium silicate mines around the world that would convert the olivine and serpentine into carbonates. The newly formed carbonates would then be put back into the mines for permanent disposal.The Ohio group is fine-tuning their high-pressure, high-temperature, three-phase fluidized bed reactor, an apparatus that uses a mixture of acids to dissolve serpentine in an aqueous solution of carbon dioxide. “In 30 minutes we can convert about 25 percent of solid magnesium silicate to carbonate at 1,000 [pounds per square inch] pressure and 80 degrees Celsius,” says Ah-Hyung Alissa Park, lead author on a presentation about this technique at the American Institute of Chemical Engineers in November. “At higher temperatures and pressures the conversion rate goes up.” Still, the science is in its infancy, Lackner says. “It is an example of where we learn more the cleverer and better we will get.”

So there we have it. My mind is open on this subject. I still think it’s quite interesting… although I do question the economics of ameliorating the consequences of coal use through mining and crushing five or six times as much rock as the coal we burn. If there is a way around that issue, someone please let us know.

One question which has occurred to me is just how powerfully is the carbon bound up in the resulting mineral? If it is only bound lightly, could we use these carbonates to recycle the carbon back into liquid fuel using power from nuclear reactors? While the economics of using this technique to continue burning coal might not necessarily work, perhaps it has other uses in an advanced nuclear economy.

Further Considerations of the Complexity Ethic.

Thinking back on the time when my friend first announced the complexity ethic to me, I know he was reading a number of books on subjects such as ecology, sustainability, energy policy, peak oil and general history. I’ve asked him if he recalls any particular material which influenced him to consider complexity from an ethical perspective. The following is the list which he came up with:

Emergence: The connected lives of ants, brains, cities and software.
Steven Johnson, Touchstone Press, 2001.

The Hidden Connections: A science for sustainable living.
Fritjof Kapra, Harper-Collins, 2002

Sync: The emerging science of spontaneous order.
Steven Strogatz, Theia, 2003.

Ubiquity: The science of history… or why the world is simpler than we think.
Mark Buchanan, Crown Publishers, 2000.

Our discussions on these and other topics formed a kind of loose dialogue (occasionally broken off for long periods) which my friend and I have been having on the prospects for humanity for many years now.

Academia’s interest in the topic of complexity goes back much further than the turn of the century, of course. Consider the following:

“Organized complexity here means that the character of the structures showing it depends not only on the properties of the individual elements of which they are composed, but also on the manner in which the individual elements are connected with each other. In the explanation of the working of such structures we can for this reason not replace the information about the individual elements by statistical information, but require full information about each element if from our theory we are to derive specific predictions about individual events. Without such specific information about the individual elements we shall be confined to what on another occasion I have called mere pattern predictions- predictions of some of the general attributes of the structures that will form themselves, but not containing specific statements about the individual elements of which the structures will be made up.

This is particularly true of our theories accounting for the determination of the systems of relative prices and wages that will form themselves on a well-functioning market. Into the determination of these prices and wages there will enter the effects of particular information possessed by every one of the participants in the market process- a sum of facts which in their totality cannot be known to the scientific observer, or to any other single brain. It is indeed the source of the superiority of the market order, and the reason why, when it is not suppressed by the powers of government, it regularly displaces other types of order, that in the resulting allocation of resources more of the knowledge of particular facts will be utilized which exists only dispersed among uncounted persons, than any one person can possess.”

-F.A. Hayek, “The Pretence of Knowledge’ (1974 Nobel Lecture).

And this:

“…we have both observational and theoretical reasons to believe that the general principle holds: Complexity is an important factor in producing stability. Complex communities, such as the deciduous forests that cover much of the eastern United States, persist year after year if man does not interfere with them… a cornfield, which is a man-made stand of a single kind of grass, has little natural stability and is subject to instant ruin if it is not constantly managed by man.”

-P.R. Ehrlich and A.H. Ehrlich, Population, Resources and environment. (Freeman, San Francisco, 1970) p.159.

Friedrich Hayek and Paul Ehrlich seem to be saying very similar things here, although in different contexts. Having those two individuals in agreement with each other is surely remarkable enough to flag that something interesting and unusual is going on with this topic.

The Ethics of Complexity.

About half-a-decade ago I was helping a friend in his garden when he announced to me his new ethical framework. I was involved in that instant in ripping weeds out of the garden bed, a task which my friend was constrained from by repeated attacks of gout, and for which he paid me richly in beer and bourbon.

“I’ve just come up with a new ethical system.” He said. “It only has one commandment: Thou shalt not reduce complexity!” Later on he decided that particular expression of the core concept was too negative, and proposed “Foster complexity!” as a more positive formulation.

I paused in my labours for a bit to consider this idea. I thought at the time that it had considerable merit, and I still do. When we consider the central ethical tenets of the major philosophical and religious systems, we can see that pretty much all of them are expressing the same basic idea in different ways, and with different emphases, but what is that core idea? Although it is perhaps obscured in some interpretations, they all seem to attempt to provide a cultural framework for the maximisation of complexity in one form or another.

If someone is murdered, the complexity of the universe is diminished. If a forest burns up, complexity is diminished. If a peasant-society’s crops fail due to drought, complexity is greatly reduced. If a city is levelled by a nuclear bomb, complexity is greatly reduced. Most, if not all undesirable things and situations seem to involve a reduction in complexity, while most if not all desirable things appear to be an enhancement of complexity in one form or another.

One thing that greatly interested me about this notion is the possibility that complexity can be mathematically defined and quantified. If we reach that capability, I suspect that many complex ethical questions are susceptible to a mathematical solution… such as the relative balance of interest between environmental and economic concerns.

Well that’s all well and good, but what does it have to do with nuclear power?

Perhaps when considering the merits and downsides to various energy solutions, we might ask ourselves how their implementation will impact the net complexity of our environment and economy. Does the proposed technology have a severe impact on the net complexity of the living world? Does it allow for the growth of complex, intricate social and economic forms in our society, or does it constrain them through impoverishment and resource diversion? Over my next few posts I might consider some of these issues in relation to nuclear power and its competitors.

About this blog.

We exist in a sea of electromagnetic force, and are for the most part utterly subject to its dictates. One other force makes itself blatantly known in the course of our mundane activities, namely gravitation, but electromagnetism packs far more power in its punch. It takes a mass the magnitude of Earth to make us weigh ten Newtons to the kilogram, but with a simple rearrangement in the structure of a vanishingly, ridiculously tiny portion of Earth’s mass, we can override the gravitational force of this entire planet, and stand on two feet (by burning sugar in our cells) … or fly to the other side of it in a 747 (by burning hydrocarbons in a jet engine).

The sheer divide of magnitude between the two phenomena is obscured in our minds by the fact that the only kind of object great enough for us to sensibly experience the power of the lesser force is a world. The world is our universe. How can a basic overall fact of life which everyone experiences (stuff falls down) have any relation to the growth of plants, or the warmth of the hearth on a winter’s eve?

The proportional difference between the amount of mass needed to make a sensible impact for the strong nuclear force and the electromagnetic force is nowhere near as great as that between the electromagnetic and gravitational force, but it is huge nonetheless. Once again we are faced with a sharp fracturing of our experience, but this time in a direction which contradicts our innate sense of cause and effect to a much greater degree than the considerations leading us to appreciate the weakness of gravity. This time we move in the direction of far greater power, and the realm of graphic, iconic consequence.

The images of the early nuclear age have a certain amount of baggage which we need to move beyond to make informed choices for the future. This blog is my humble attempt to encourage people to make that move.