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hello and welcome to technically speaking a podcast where scientists and engineers come together to chat about a common interest share knowledge and satisfy some curiosity i'm laura and in this episode i'm joined by antonia in ginor to talk about how carbon dioxide is used or produced in various industries and that just happens to follow unless you from our zero waste episodes that came just before these two so if you've not checked them out once you've finished listening to this go and have a
look back through our catalogue let's start off with for this episode antonia what do you know about co2 and how it's used in industry co2 stands for carbon dioxide and interestingly it's been in their headlines because of the recent gas prices being so high that we've actually got a carbon dioxide shortage in the uk and it's funny to think that because we're constantly talking about greenhouse gases we have too many so the fact that we're we're trying to cut it
but it's also actually a necessary part of various industries like food shows that co2 isn't just a bad thing yeah that's very true there are positives and negatives to it's a very good point uh ginwar do you agree with that yeah i think i relate to co2 personally because it is controversial and i'm quite attracted to controversial uh subjects actually it is in excess as antonia said in the atmosphere and it is changing our climate and in that term we are deploying a huge effort and large funds
to reduce it but at the same time co2 is also in shortage and to the point where it can threaten the national food security in a country like the uk yeah so i think the question now is how can we have an access and a shortage of the same material at the same time i think uh laura you can elaborate on that more because you've worked on kind of uh carbon capture and storage during your phd i did yes so i i finished my phd about eight years ago and it was about simulations of carbon capture at
the molecular level so i was essentially looking at how the energy industry could use technology to capture carbon dioxide from its emissions and from what i remember i mean it's eight years ago and my memory isn't great but it can be done but it's not necessarily straightforward and it would require a lot of energy to be put into that process to capture the co2 and then recover the material that you used to do the capture with back when i was doing this research which is
before 2013 it was said that the amount of energy you'd need to put into this process would effectively lead to more co2 production because it would require more energy than the industrial process would normally use yeah which is unfortunate i'm not sure that situation has changed too much in the intervening years i might be wrong because i haven't kept up to date with it but back then the idea was to just store and then dispose of the co2 from the energy industry rather than making
use of it when you when you say that the process requires more energy what kind of energy you're talking about yeah the materials i were looking at it seemed like it was quite a passive way of capturing it but then to regenerate that material so you can reuse it again you'd have to apply heat okay and heat may come from any source of heat so if i guess if you were going to use some sort of electrical heating the electricity production didn't generate any co2 then it would be more
sustainable okay at the time obviously before 2013 we were still quite reliant on coal for our energy supply yeah that would have pushed up the carbon dioxide emissions yeah yeah what sort of temperature were you having to regenerate the material because i think i think the challenge particularly in the uk for decarbonizing heat is just simply the temperatures required is greater than what electricity provides at a cost effective or carbon equivalent way to our mainly methane uh usage
yeah yeah you're stretching my memory here let's say let's say for argument's sake it's about 100 degrees celsius i would guess you've got quite a lot of material so quite a large heat input this isn't just like you know turning on a kettle say yeah you've got these huge chimney stacks or whatever it was to deal with and there was there were more complications than that because obviously you don't just have co2 coming out of a flue gas from a power station you've got other what are called small
penetrant molecules like nitrogen and various other things that would compete in that material to be captured by it as well as a co2 yeah so it's not just a straightforward saying you can stick something in the flue of a chimney and capture the co2 there are more things to consider so energy was one side of it and then what else it's trying to capture and then what to do with it afterwards was another thing thank you laura for clarifying that sorry i feel like i've been put on the
spot now it's uh so long since i've looked at this so we started talking about this because there was a co2 shortage in the news recently and it comes from methane antonia i think you were looking into this weren't you yeah it comes from using methane yes to make fertilizer so the business secretary convinced fertilizer plants to start up again for the production of co2 which which seems odd we're kind of short on food but it's not because of the fertilizer but it's
because we need 2-2 the co2 is a by-product of fertilizer production if i go into what i understand as the chemistry and hopefully someone else might jump in is a process called methane reforming a lot of chemical reactions happen in the steps to get to fertilizer but the first initial step is turning methane into carbon monoxide and hydrogen carbon monoxide is converted into carbon dioxide through further reaction with steam cleaning that up or in the industrial term scrub you can get quite
high purity of co2 liquefy it and then use it in other industries because it's a byproduct you don't necessarily run a plant to make co2 your main product is the fertilizer so the fact that we have a supply chain shortage is because of the gas prices being so high people don't want to purchase the high gas prices to make fertilizer and then that makes co2 get a high price ironically because of gas and energy prices going up it's a very weird interconnected supply chain world isn't
it it is it is indeed i guess that's like a lot of the supply chains you're saying gas that's like natural gas that i would burn on my hob when i'm cooking right sorry yes natural gas is mainly methane and i've jumped a few steps again see when i was reading about this in the news i just automatically went oh gas so they're burning it to heat something up because that's what i use gas for but you're right it does have methane in it and i haven't even considered that they
were using the methane for something else to make a chemical reaction take place so i feel a bit silly now i think it depends on your background when you get into chemical engineering there's all this talk about c methane reforming hydro cracking syn gas and then later on in this in the fertilized production there's the famous harbour bosch process ask any any chemical engineer or chemist they can tell you about harvard bosch not me oh i forgot it i think i mean i forgot it until last week
this reaction actually the seo plus plus team giving hydrogen and co2 it reminds me of using the co2 also as a feedstock for making methanol which is another energy source yeah and there's actually now two large pilot plants for production of methanol from co2 in japan which is a more direct way of producing methanol rather than adding steam to it to produce hydrogen and co2 and then use these two to produce methanol so the direct way is just to produce let's say captured co2
and hydrogen and make methanol in in a more sustainable way the key in this process is to use high pressure and sometimes using catalyst because co2 is really hard to to make it react so is the idea that they'll use co2 that will eventually be acquired from carbon capture technologies yeah it is indeed okay because i also associate methanol with burning things to eat stuff up this makes you sound like a pyromaniac i'm not but to me it seems counterproductive to
so if you're saying that the co2 is byproduct of converting methane which comes from natural gas which i've burned that just sounds like a really complicated way to make something that you can burn when you've already got something i suppose the beauty is is you remove the co2 but then if do you burn the methanol would methanol just produce co2 again yes or did they use methanol for something else the methanol you can use it for various stuff it can be a solvent
it can be used for further chemical reactions yeah i think it's just me that associates methanol with burning things is methanol a liquid at room temperature because maybe it's preferable to having methane which you know which is a gas at room temperature and then you'd have to pipe it around so it is a liquid in room temperature well in like sort of heating and transport it's definitely easier to handle liquids than it is gas so i suppose methanol might be preferable
even yeah but then i guess if you're thinking about burning it to release the energy i guess neither one of those things is practical if we're trying to reduce carbon footprints of various technologies because they both would produce co2 when they're burned right um yeah but then you could capture it again and just just close that cycle just go ahead full circle yeah yeah that's a look yeah i did say this followed on very well for my episode it's about zero away
so what they were talking about in the news was if this is shortage of co2 one of the industries that uses it is for food storage yeah preservation yeah you don't really think about how all these um the gases are used in these different industries the work that i did in the chemistry lab and i'm not a chemist i haven't done a lot of it but i the gases that we tended to use if you wanted something in their atmosphere either nitrogen or argan so whenever you get a package of food that is being
packaged in a protective atmosphere you know those bags of salad that you get in the supermarket they're always quite inflated like little pillows i've always just assumed that's just nitrogen because that's what i'm familiar with but apparently there's co2 in there as well you're right because nitrogen is inert and co2 is inert so if it's about that we may use both which one is cheaper i didn't get a very good answer as to why co2 would be used um although
i did find some companies that said that they could use nitrogen as well okay also that it's not a pure co2 or a pure nitrogen atmosphere they mix the gases sometimes depending on exactly what's being packaged that tells quite well about plants but whether they want to feed the plants actually since you or two while packaging them oh yeah so yeah before we started recording this episode and sonia and i were wondering if you have that bag of salad it's just salad leaves
right it's not got any roots it's not only soil is it still using that co2 because that's how plants photosynthesize basically is it dead or alive is it still doing its thing is it dead when it's packaged in that protective atmosphere i don't know do you want to eat a dead plant i think it's better if it's still a bit alive right something that you shared was um how people preserve meat and oxygen to keep to keep its color so same thing with plants right you'd want them to still
kind of look fresh fresh is it tasty i'm just reading about it at the moment and they said it's dead once you've just take it out of the soil but it's not if you put it back in the soil it goes it can come alive again but i always think that plants they do alchemy essentially they take soil and they turn it into food and i don't have to do anything i actually have to keep putting water on it i'm in aura plants a little bit they can do things that people can't like
scientifically we know how plants do it but for us it's still magic right we know we know how it works to marvel at the natural world i would say but we did have a bit of a conversation before we started recording about why you might use co2 over other gases my thinking it goes to again chemical reactions for purifying these gases could take a lot more energy so you also want them to be liquefied and from the top of my head i think co2 would be liquefied as a higher
temperature less cold temperature than nitrogen co2 sublimes doesn't it so it goes straight from the solid into a gas you can get a triple point for co2 which is where it can be in all three states i'm going to say at the same time that's probably not quite the right phrase i think that is the um the term isn't it maybe i just find it a bit a bit weird that a thing can be in three different states solid liquid and gas all at the same time it's very schrodinger's cat
like as a chemist i'm not very much surprised but i i can i cannot imagine it as you said i don't know how to imagine it i can imagine the liquid equilibrium diagram i can't imagine physically what exactly is that yeah me too like this is the episode we talk about science that we understand but don't quite comprehend we know what that graph looks like i don't know what it really looks like i think purity is probably quite important because i got the impression
that the reason that the methane is used and then the co2 is the byproduct you get mostly co2 of that so it's fairly pure and you need a particular purity of co2 um particular things like storing food yeah yeah it got to be a co2 for food grade isn't it antonio you mentioned that oxygen is used to package meat and apparently that's because the co2 can make the meat go rancid because it gets absorbed into the meat and acidifies it slightly i think my summary of when i was reading through
this is although the news is reported a lot that co2 is used in food packaging it's not only co2 it's more complicated than that that seems to be a common theme with our choice of podcast topics yeah and the more you start reading into this to prepare for each episode the more you go down this rabbit hole of all this this this aspect of this subject is really interesting like we've just spent about 10 minutes talking about food packaging and haven't really touched on
our our main focus of this episode about how we can can or can't um suck co2 out of the atmosphere and redress that this idea that there's too much in the atmosphere and not enough where we need co2 yeah so how do we capture it at the moment maybe we could discuss that a bit the work that i was doing in my phd and this isn't a technology that is currently in use as far as i'm aware but it was a polymer that looks a little bit like um well a little bit like the packaging
that's used to package that solid those plastic bags but it's kind of yellowy and a little bit crinkly and that's a membrane it's made of this polymer that's intrinsically porous so it had these these very tiny pores that were roughly the same size as the co2 molecule the the gases could pass through but it also had in mind group that the co2 would preferentially absorb onto the surface obviously they'd be trapped in these little cavities that quite liked to have the co2 sitting
there but then as i was saying the the intent was this would put on a gas or a coal-fired power station and there are other molecules in the gas that would also like to sit in those little tiny favorable sights so again it's more complicated than just sucking co2 out the atmosphere um i think there are some other technologies though actually there's a lot of ways of decontaminating or capturing anything that needs filtration or decontamination using a membrane or using any kind of adsorbent
which can be a polymer or a clay or a membrane there's always this problem of selectivity so we don't have still the technology that has this kind of high selectivity we're still at industrial level we are still using just we are just using the non-selective processes because the more the the advanced one are not really proven to be really selective whenever it comes to a medium where you have several competing components all together trying to get through that
membrane or trying to absorb on whatever adsorbent you have i don't think the technology is not advanced because of that am i talking i think i get it so you're sort of saying already in industry we don't use particularly selective technology you're researching more selective things but it's sort of not the barrier to it being implemented the barrier is other issues just because i know co2 from chemical from chemistry point of view that it is an inert molecule it means when the co2
forms and when the carbon and oxygen bind together they are at their lowest energy state so they just happy there they don't want to react with anything else unless you give them a lot of energy or you use really um advanced catalysts to do their reaction and therefore the use of co2 feedstock is not very economy maybe that's why the co2 is not or the co2 technology capturing technology is not quite advanced yet i think that was something that was one of your considerations or wasn't it was once
you've captured the co2 what can you even use it for wasn't it and it's so exactly but if we capture it what we're going to do with it oh yeah so when i was researching this the idea was that it would be disposed of somehow there was separate research looking at how it would be disposed of like there was a vague idea to just dissolve it into the sea which is obviously from what we see with climate change really not a good idea because it acidifies the sea yeah
but you're absolutely right there isn't really any there's no use for the co2 on a big scale so i guess no one's really motivated to find a technology that will do something because there are too many other barriers to implementation like what do you do with the co2 afterwards yeah if it can't be used to make something useful then we're just capturing more waste i think that is sort of the economic challenges as a company you wouldn't spend money separating out products that you don't need
unless it harmed the product in the end so you know up till now we never thought that burning fossil fuels was necessarily bad main product was energy and heat or electricity and then a byproduct was water vapor and and co2 and we thought yeah that's okay now we're realizing that we actually do need to separate it and you know if there's no income coming from it it it can be quite hard to sustain so yeah i think that is probably why we never thought to uh to separate it
you were talking about selectivity before and co2 is in the atmosphere in very small concentrations in comparison to nitrogen and oxygen so if if you are talking about developing that selective technology you're talking about a relatively small concentration of a gas that's also competing with other gases to be removed yeah i think most of the asian techniques that we work in the lab with they work with very very very low concentration talking about ppm or ppb so it's quite i think we're on
the same level so it's quite challenging to capture these ppm level molecules and leaving everything else just passing through the membrane or just not adsorbed yeah that was my impression uh antonia you were looking at some other technologies like sort of a liquid gas separation i guess what would you bubble the gas through some does that sound right or am i just making stuff up yeah you have a an absorption of the co2 into um into a liquid amine of some sort quinoa has
talked about is is selectivity if it's too selective and it doesn't let go of the molecule you can't reuse the amines you create another problem isn't it but because you want it to be a result reversible and kind of a way to liberate the the contaminants from whatever absorbent you have one of the sort of challenges is the a means recycling god i can't remember what i can't remember the word it was recovery i guess no no we can skip it we can spin it because i my brain has gone fried now so
i guess it's worth pointing out that there are other industries that also produce co2 and so i've done a little bit of work with cement and concrete production i know that it gets produced from that as well we mentioned that in the episode that we did on um how can you make me care about concrete quite a while ago now and it's also producing steel production as well and it sounds like that's one industry where it's going to be quite difficult to decarbonize so maybe that's where if
carbon capture technology is developed to a commercial scale that's where it would be used burning natural gas in the energy industry is quite interesting methane instead of it being a fossil fuel we could we could get it from an aerobic digestion but just remind me of the buses in bristol they are using methane rather than diesel or whatever so where do they get the methane from is it from anaerobic digestion i haven't asked the driver yet but i will whenever
i'm in bristol but what are they turning it into aren't they burning it to produce yeah i'm coming co2 to burning stuff again yeah why would we use methane instead of petrol or diesel the methane is a greenhouse gas but it's not it doesn't hold the heat in it as much or contributes much to global warming as much as co2 does right oh it does though on a shorter time scale it's more potent but it decomposes faster than co2 the biomethane gas that use the buses is it
comes from waste food and is supplied from anaerobic digesters biomethane gas offers more than 85 percent reduction in greenhouse gases compared to older diesel buses and helps to improve air quality here's um here's a really interesting one in the beer industry you'd sort of produce co2 from the fertilization not fertilizer fermentation process flordo lord see which type of fertilizer implants it is it's very confusing we definitely do not but well we do fertilize but we're
fermenting the crops to make beer but in that process the fermentation process you get carbon dioxide and later on in the process after they've filled their tank and they need to empty the tank they would actually use a bit of that carbon dioxide to push the beer back out because it's got the right kind of gases in there so rather than using oxygen containing air they would use co2 it's kind of funny to think that if a company didn't capture the carbon dioxide from
the fermentation process then they're sort of buying canisters of co2 to do that and it's if there was a way to capture it they could just reuse that but it's it's difficult on a on such a small scale to be able to create basically an entire other chemical plant attached to your existing plan to capture all that just for this very specific small use i see you see you're saying that the beer industry buys in co2 even though they produce it yes oh that is weird so we've made some home
brew um at home in like this specially made bucket thing and you're right it gives off this gas and it makes something you don't say noise and it doesn't it has changed me so much because it's not regular you can't predict when it's going to happen but it happens with enough frequency to distract you from what you're doing bizarre occasional burping semi random annoyance i suppose the disturbance is worth it in the end when you when you've got your home brew beer it can be you
never quite know what you're getting i mean i assume to some extent it depends on the quality of your tap porter yeah it's back to another podcast episode i guess it is another podcast episode how is your tap water doing recently it's it seems fine um i've not noticed any changes in flavor we're still using water there's still a big plan to bring water from elsewhere in the lake district so we can stop drinking partially boreholated water that is not a word and i feel like we're going so far off
topic but it was great to hear about how how's your little um bubbling burping is is it does it smell like fart like it smells like a brewery pretty much oh okay that's nice then that's that's a nice smell in a way i just remember that sweet i don't know if you used to have it when you were uh kids that sweet that when you put it in your mouth start bubbling and tickling because it has co2 actually inside oh is that what popping candy has in it so yeah i guess to try and sum up this very
rambling conversation so we talked about how um co2 was used or produced in the electricity industry we touched a little bit on steel and cement making and we talked quite a lot about the food industry and how it's used to preserve various products and of course we talked about the fertilizer industry and how that produces co2 and we talked a little bit about how it could be captured from other from industries rather than going into the atmosphere but either the technology or the willingness
isn't quite there to do it yet perhaps because it's so difficult to use co2 it is pretty much just a waste that goes into the atmosphere but i guess there's more work there to do to make that into a circular economy and reduce our carbon footprint in the world so i think we'll leave it there and if you want to ask us any questions or ask us what the hell have we just talked about you can find us on twitter or you can leave a comment on this episode the views expressed in this podcast
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