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Carbon dioxide "shortage"

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Brock
1390402.  Mon Sep 20, 2021 2:02 pm Reply with quote

Well OK then. I hadn't realized that the process that creates CO2 as a by-product during the production of ammonia resulted in liquid CO2 rather than the gas. I shall need to read up on it more.

 
Brock
1390430.  Tue Sep 21, 2021 3:52 am Reply with quote

As it happens, this issue came up on Radio 4's Today programme this morning, in an interview with Stuart Haszeldine, Professor of Carbon Capture and Storage at the University of Edinburgh. (Starts around 1:12:45.)

https://www.bbc.co.uk/sounds/play/m000zt8s

As a short-term solution to the crisis, Prof Haszeldine suggested three solutions:
(1) Government subsidy of the two fertiliser plants in Merseyside and Teesside, so that they produce CO2 as their main product rather than a by-product.
(2) Taking CO2 from the brewing and grain distilling industries, which already produce hundreds of thousands of tonnes of very pure food-grade CO2 as a by-product. Some capture CO2 to use internally, but a lot is vented and not used.
(3) Importing CO2 from fertiliser plants in Europe - in particular there's one to the south-west of Oslo which already imports into Teesside.

Then at 1:14:55, Nick Robinson asked a similar question to mine at the start of the thread. Here's a slightly edited transcript:

Quote:
NR: Longer-term, could there be any link with our desire to remove CO2 from the air to deal with climate change and our need for it in manufacturing?

SH: Yes. We need to capture CO2 at immense scales - tens, hundreds of millions of tons per year, much more than we need for fire extinguishers, food packaging or dry cleaning. That's something that we can and should be doing. It's likely that in October this year the Government will announce two industrial complexes which will be starting to capture very large amounts of CO2.

NR: Primarily for climate change, but could it also be used to reduce our over-dependence on a couple of foreign-owned fertiliser firms?

SH: It would increase diversity of supply, which is a good hedge against one of our sources of supply going offline. But the wholesale use of CO2 is relatively minor compared with the millions of tons that need to be captured and stored deep underground for reducing the effects of climate change.


So, far from being a "silly thing to do", it looks as though the UK may be about to embark on precisely the course of action that I was suggesting!

 
crissdee
1390436.  Tue Sep 21, 2021 4:24 am Reply with quote

You say that like "government action" and "silly thing to do" are necessarily opposites!

 
PDR
1390442.  Tue Sep 21, 2021 5:07 am Reply with quote

Brock wrote:

So, far from being a "silly thing to do", it looks as though the UK may be about to embark on precisely the course of action that I was suggesting!


I heard the same interviews, and other than just the vague general principle there was nothing about how it would be done on an industrial scale, so I'm sticking to my view that it is not practicable on an engineering and/or economic basis.

These are not trivial problems, and there is little point in using a CO2 liquefaction process that itself has a large energy/carbon footprint.

PDR

 
Celebaelin
1390445.  Tue Sep 21, 2021 5:53 am Reply with quote

A few things occur to me - firstly CO2 recovery from eg natural gas power stations should be possible; take this item from 2011 as at the very least a reasonable starting point. Ultimately this should (or could) also make electricity cheaper.

Quote:
Abstract:

The chapter begins with a description of the industrial CO2 production process. The remainder of the chapter is focused on oxy-combustion flue gas CO2 purification, including process description, energy consumption, CO2 recovery, capture costs, emissions, recent advances and future outlook.

https://www.sciencedirect.com/science/article/pii/B9781845696719500119



Secondly, and I'm unsure whether this is cost efficient in either economic or CO2 emission terms (unless you use power from a plant that reclaims its CO2), freezing air (or more importantly in this specific case brewery off-gas) down to -78C would solidify any carbon dioxide content as dry ice. Now solids are not a great form for product collection and maintaining operation of plant but since N2 (and presumably O2 as a result of the same process) is already produced by fractional distillation of liquid air a methodology to cope with this must already exist. CO2 is transported, stored and handled in liquid form, either at ambient temperature (in cylinders or non-insulated storage tanks at a pressure of 45-65 bar) or refrigerated (in insulated tankers and storage tanks) at temperatures between -35 C and -15 C and pressures of 12 to 25 bar so we can infer that one of those would be the best form in which to produce carbon dioxide from our new source - initially it would be whatever the advantages of other specifications might be.

https://www.linde-gas.com/en/images/LMB_Safety%20Advice_01_66881_tcm17-165650.pdf

Oh, and thirdly we should have switched to cellulose-based plastics in all suitable roles a long time ago and the complete* bio-degredation of waste materials generated by this stream could easily produce a CO2 rich gas under the in-tank action of eg actinomycetes as the plastic would act as the micro-organisms respiratory carbon source@. Meanwhile these production methods as a whole would actually strip carbon dioxide from the atmosphere by sequestering the carbon in the form of usable plastics, their precursors, other products and potentially liquid CO2 reserves.

* as opposed to enzymically digesting the waste cellulose down to, say, a paste from which new cellulosic plastics could be made. Since I'm already on record with this idea elsewhere I'll say that you can make sugars if you digest down far enough and you can do lots of things with sugar made from the waste stream if only people weren't so pigheaded about existing (and as we now mainly accept, failing) technologies.

@ almost completely analogous with brewing except you don't get a product as well. Existing industrial biofermenters are another potential source with the added benefit that they make antibiotics and stuff while they're doing it. You could do this with green waste too - compost it in a controlled manner essentially.

P.S. One further thought occurs - can CO2 production ever be carbon neutral as making CO2 is its whole purpose; or at least much of it. Even if the effect of the processes actually reduce atmospheric CO2 through sequestering there's no denying the output. Offsetting would essentially consist of planting softwood trees or similar which would eventually become a feedstock for building materials, paper manufacture etc. meaning because of wastage and eventual passage into the refuse stream some proportion of them have to be replaced as well as planting new trees for that year's production. Any financial benefits that might be gained by being carbon neutral might need to be re-examined in this instance as potentially the best way to reduce atmospheric CO2 could turn out to be increased CO2 production; it's a convoluted path of possibilities but that might be the case because of eg transport times and increasing quantities held in reserve on an ongoing basis assuming an expanding market. Clearly the concern also applies to any future carbon tax that may be implemented.

Also I can't get it out of my head that CO2 freezes at -44C. This is something I 'learned' at school only to find out much later that it's wrong; unless I remember to remember though I'll always trot out the incorrect -44C figure.


Last edited by Celebaelin on Wed Sep 22, 2021 6:11 am; edited 1 time in total

 
dr.bob
1390491.  Tue Sep 21, 2021 9:47 am Reply with quote

Celebaelin wrote:
P.S. One further thought occurs - can CO2 production ever be carbon neutral as making CO2 is its whole purpose; or at least much of it. Even if the effect of the processes actually reduce atmospheric CO2 through sequestering there's no denying the output.


I guess it depends how the CO2 is initially produced. It's often claimed that burning wood to heat your home is carbon neutral since the only carbon released into the atmosphere is the carbon that was absorbed by the tree as it grew and that carbon will once again be absorbed by another tree before it's chopped down and burned again.

It's the circle of life.

(cue the music!)

Ingonyama nengw' enamabala

 
PDR
1390518.  Tue Sep 21, 2021 11:41 am Reply with quote

It also depends what you mean by "carbon positive". In the usual context it's about the release of substances into the atmosphere that create/exacerbate greenhouse effects (or whatever the current term is). Producing CO2 solely to be bottled and then "consumed" as a chemical precursor or as feed hydroponics (to name but two) then it is never released into the atmosphere and so its production could be deemed "carbon negative".

PDR

 
Celebaelin
1390602.  Wed Sep 22, 2021 6:34 am Reply with quote

dr.bob wrote:
It's often claimed that burning wood to heat your home is carbon neutral since the only carbon released into the atmosphere is the carbon that was absorbed by the tree as it grew and that carbon will once again be absorbed by another tree before it's chopped down and burned again.

That's a very blinkered way of looking at it IMO; it would imply that it's not the fault of the CO2 producer if nature doesn't sort the problem out. When there isn't sufficient vegetation to absorb the emissions within 'easy reach' of the point of generation that compounds the problem as there is what I'll chose to call a 'transit time' element which increases the CO2 content of the atmosphere because of the delay in removing it.

We need to compensate for CO2 of all sorts and the principle of 'polluter pays' should apply making eco-friendly energy more competitive (unless some fuel/power companies chose not to pass the price increase on to their customers).

The reported CO2 shortage could be instrumental in making these changes happen and in enabling new technologies; if so then I'll only be a bit more than 25 years ahead of my time.

 
Celebaelin
1390616.  Wed Sep 22, 2021 7:52 am Reply with quote

PDR wrote:
It also depends what you mean by "carbon positive". In the usual context it's about the release of substances into the atmosphere that create/exacerbate greenhouse effects (or whatever the current term is). Producing CO2 solely to be bottled and then "consumed" as a chemical precursor or as feed hydroponics (to name but two) then it is never released into the atmosphere and so its production could be deemed "carbon negative.

If the eventual fate within a pre-determined timescale* is that the carbon is returned to the atmosphere as CO2, CH3 or other related compounds then that must be considered as 'release'. The CO2 used for the purposes of food preservation is essentially immediately returned to the atmosphere - its sequestration lasts a matter of weeks. Carbon sequestered in food sources also quickly cycles back into the atmosphere (assuming no overall increase in biomass) so after harvesting only that element held as reserve foodstocks would count as sequestering. Carbon in paper products has diverse fates and a quick analysis is hampered by the fact that the EPA municipal waste figures and the UK.GOV annual waste stream figures appear to differ by a factor of 5@. A distinction between recycled and non-recycled products and products which constitute a substantial intention for sequestration (such as published books) should be made I guess. Furniture and finished and fitted tonnages of building materials would naturally have a longer lifespan as sequestered carbon - I'd imagine the average expectation could be over 50 years.

* This needs some exacting analysis using reliable data to determine realistic time periods for the various categories.

@ 2018
EPA - 292.4M tonnes of municipal waste, 23.05% paper products (?67.4M tonnes?)
UK.GOV - Commercial & Industrial 42.6M tonnes, Household 26.4M tonnes, with 153.2M tonnes not assigned to these two categories (222.2M tonnes total) 3.7% paper products (8.22M tonnes)

Statista suggests UK consumption of paper products to be over 8M tonnes/annum which would fit the UK.GOV figures and suggest that perhaps the 23.05% is the fraction in the Household waste category with the balance coming from Commercial & Industrial waste (the rest of the waste stream is largely from dredging, demolition and excavation). I would suggest that the UK consumption of paper is higher than this 8M tonne figure but that we throw away about 8.2M tonnes year (down from about 9.3M tonnes roughly 30 years ago).

https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/national-overview-facts-and-figures-materials
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1002246/UK_stats_on_waste_statistical_notice_July2021_accessible_FINAL.pdf

As a final worrying thought have a look at this.

https://www.theworldcounts.com/embed/populations/124?background_color=white&color=black&font_family=%22Helvetica+Neue%22%2C+Arial%2C+sans-serif&font_size=14'

 
dr.bob
1390694.  Thu Sep 23, 2021 5:16 am Reply with quote

Celebaelin wrote:
That's a very blinkered way of looking at it IMO; it would imply that it's not the fault of the CO2 producer if nature doesn't sort the problem out.


I don't think that's an entirely fair comment.

AIUI the argument goes that burning carbon that comes from sources that have been grown within recent times (e.g. within a person's lifetime) is significantly better for the environment than burning carbon that's been locked away for millions of years.

If the industrial revolution had been solely powered by wood* then surely levels of CO2 in the atmosphere wouldn't have changed very much. There is a constant cycle of releasing carbon into the air which is then recaptured by new plants which grow.

The main problem with climate change has been the burning of fossil fuels. This is carbon that's been removed from the air and locked away in the ground. Now that we're releasing that back into the atmosphere, we're returning to levels of CO2 not seen since the dinosaurs roamed the Earth.



*We'll leave aside how utterly impractical this is for the moment

 
Celebaelin
1390733.  Thu Sep 23, 2021 9:58 am Reply with quote

I can understand that people who burn wood in an attempt to have less of an ecological impact might find my take on the matter unsympathetic but the fact is they are still accelerating the return of sequestered carbon to the form of atmospheric CO2 even if they're only using fallen branches and sources such as unusable/discarded wood from managed forest.

It would take me a lot of work that I'm not about to dive into to form an opinion on the separate impacts of coppicing for charcoal, deforestation for agriculture, wood burning and the utilisation of fossil fuels but the order I've listed those factors in is, I suspect, that of increasing impact on elevated CO2 levels. My point however is not about extent it is about the fundamental nature of the process at this point when we need to achieve an overall carbon negative methodology for energy provision.

I'm not denying that fossil fuels are the biggest problem but they are just that - the biggest but not the only contributor to elevated carbon dioxide levels. I fear that turning over areas of largely unproductive mountainside to coniferous forest will not be enough to redress the rapid rise in atmospheric CO2. We need to create methodologies within a commercial context that make carbon sequestration not only desirable and necessary but also profitable and then let that process loose in the world (clearly with me as the franchisor ideally) and let people make money saving the planet!

Not that I think this exaggerated case is achievable but imagine if we could replace all the oil-based plastics with biodegradable cellulose-based plastics that left to their own devices would rot* away over a rather shorter timescale than natural wood does. Within limits this would allow the regulation of CO2 emissions by variation in the levels of activity in one or more areas of 'the cellulose-based plastic cycle' and could make collection of discarded packaging for recycling from any region a potentially profitable activity@ negating much of the need for the utilisation of fresh plant feedstocks. Essentially it's a limited scope man-made imitation of the carbon cycle that's more closely suited to human needs and intended to ameliorate the detrimental impact that 8 billion humans have on the planet that spawned them.

* I don't much care for this word but on the basis that "short words are best and old words when short are the best of all" it must be better than 'compost'.

@ As an example levels of recycling of paper and paper products are relatively stable even as the use of paper has declined slightly. 3.1M tonnes are collected for recycling (~38% of the presence the waste stream) compared to roughly 30 years ago when it was 3.3M but from a larger total (~35%).

 
PDR
1390766.  Thu Sep 23, 2021 1:59 pm Reply with quote

Celebaelin wrote:

Not that I think this exaggerated case is achievable but imagine if we could replace all the oil-based plastics with biodegradable cellulose-based plastics that left to their own devices would rot* away over a rather shorter timescale than natural wood does.


It could have undesirable side-effects, of course. I commend the book "Doomwatch - Mutant 59: the plastic-eaters" [by] Kit Pedler and Gerry Davis for some thoughts on the potential consequences.

PDR

 
Celebaelin
1390767.  Thu Sep 23, 2021 3:33 pm Reply with quote

Unless I miss your drift - which is of course entirely possible - you're suggesting that stuff which will utilise oil based plastics will evolve if we leave loads of it around.

I put it to you that this would be extraordinarily bad news and would negate many of the positives about using oil based plastics by dint of making them (more) perishable.

I'll leave it there in case that wasn't your point... but if that was your point it seems like an enormously silly one given a moment's thought.

On checking the title you mention here silly does seem to be the salient concept.

 
PDR
1390811.  Fri Sep 24, 2021 5:36 am Reply with quote

The book was the novelised version of an episode of Doomwatch (a BBC techno-drama series from the 70s). The story was about the development of a bacterium designed to eat a particular plastic to be used in plastic packaging, thereby negating the problem of accumulating landfill (quote far-sighted for the 70s). The story turns to disaster when the bacterium mutates and starts eating other kinds of plastics.

The point I was making was the related one that if we switched from non-degradable oil-based plastics to degradable cellulose plastics (or other plant-based ones like PLA) we need to be sure we understand the consequences that will go with their limited life. We need to be sure that they have a guaranteed minimum safe working life, and we need to design so that their ultimate failure is graceful. So if they were used for insulation, or the outer enclosures of double-insulated devices, they would create a latent safety hazard unless the design approach was suitably clever. Ideally you'd want some visible indication, like plastics which changed colour just before they failed or something.

We've been here before - metal selections in Lancia car structures, high-alumina cement etc.

PDR

 
Celebaelin
1390870.  Fri Sep 24, 2021 2:07 pm Reply with quote

I'm sure cellulose plastics would be unsuitable for a lot of uses, they're not terribly flexible, not particularly strong and easily combustible but as packaging for perishable food and perhaps drinks they are probably serviceable (or perhaps could be made to be) because the secreted enzymes that degrade them, in the somewhat rare event that the relevant organisms would be present, would act much more slowly on the packaging than on the saleable contents of such packaging. There may be some technical uses for which cellulose plastics could be employed and if so then frankly 'great' but that wasn't really what I was thinking about. The organisms which degrade cellulose are relatively few in number but in an essentially nutrient free environment they might get a foothold and cause problems with a cellulose plastic component in the long term. Without knowing more about the technical details of the particular cellulose product (degree of cross-linking in particular) it's impossible to offer specifications about an imagined component but there is some room for maneuver regarding the form of the plastics generated which suggests a possible range of characteristics could be produced without impeding the 'biodegradability' which is central to the point of maximising the use of cellulose polymers.

Chemical modification of the cellulose (or it's constituents prior to polymerisation) might, with some further biotechnological/chemical jiggery-pokery, provide a product suitable for some engineering uses but is, IMO at this point, likely to be a direct replacement for the corresponding oil-based product and thus have similar characteristics as regards disposal.

Without putting in too much further thought such direct substitution is likely to be true of lignin derived products as well but they are certainly going to be far less biodegradable generally as there really are very few organisms that digest lignin and they do so in vivo only to gain access to underlying cellulose not as a nutritional source in and of itself (AFAIK).

 

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