![]() ![]() Just 0.04% is CO 2, compared to 78% nitrogen and 21% oxygen. However, as the CO 2 is spread over such a vast area, it is very dilute in the air. These emissions are the primary driver of climate change. On hearing about the CO 2 shortage, most people will instantly think: ‘Hang on a minute! If we have too much CO 2 in the atmosphere, why can’t we just take some of that and use it in the food, health and agriculture industries?’ And that’s a great question.Ĭurrently, we emit around 40 billion tons of CO 2 into the atmosphere every year. ![]() Just how control of most of the UK’s fertiliser and CO 2 production has come to end up in the hands of a single US-owned company is a question that politicians will have to answer, but chemists can do something to prevent this problem reoccurring, by coming up with new ways to produce CO 2. ‘There are technologies that can capture CO 2 from the air but since the source of CO 2 is very dilute, it is relatively expensive’ We rely on a just-in-time model instead, buying gas when it’s needed on the wholesale market. The situation is the same across Europe, where there is also a natural gas shortage, but the UK is worse hit because we don’t have as much gas storage. In fact, just two fertiliser plants in the north of England supply over 60% of the food industry’s CO 2 requirements and it’s these two plants (owned and run by US operator CF Industries) that temporarily shut down. The fact that the price of natural gas can influence the availability of a completely different commodity further down the supply chain gives you an indication of the UK’s dependence on this one single source of CO 2 production. Source: © Claus Lunau/Science Photo LibraryĬapturing carbon dioxide from the air is not like pie in the sky, but it’s currently prohibitively expensive All our eggs in one basket In fact, so huge is the price of natural gas that it recently became uneconomical for some fertiliser plants to operate, so they shut down. This is because of factors such as a cold winter in 2020, calm weather reducing the amount of electricity generated by wind and the economy waking up again after the Covid-19 lockdown. During 2021 the price of gas has increased from just under 50p per therm to over £2.50 per therm. So, what has all this got to do with the recent shortage of CO 2? The problem is the natural gas starting material, or rather the cost of it. ‘Unfortunately, the amount of CO₂ produced by the fertiliser industry far exceeds the quantity needed by other industries, so most fertiliser plants don’t bother capturing it,’ he says. However, not all fertiliser plants are geared up for CO 2 capture, reveals Mark. The hydrogen gas goes on to be used in the production of ammonia, while the CO 2 is either captured and sold as a commodity or vented into the atmosphere as waste. In fact, it’s in the food industry that the shortage of CO 2 was felt most keenly (it’s also used in greenhouses to promote plant growth and to decaffeinate coffee), and threatened stocks on supermarket shelves.Ī worksheet to assess prior knowledge and understanding of the carbon cycle from the Education in Chemistry website: rsc.li/3FtvGpI Meanwhile, in the meat industry, high concentrations of the gas are used to replace oxygen in the air animals breathe, rendering them unconscious before they are slaughtered,’ Mark continues. ‘The microbial organisms that cause food to perish need oxygen to survive, so packaging salad leaves with CO₂, not oxygen, keeps them fresh. Freeze it and you produce dry ice, which is used to keep medical materials, including Covid vaccines, chilled during transport,’ he explains. Compress it in a cylinder and you have a fire extinguisher. Trap it in high pressure bubbles in sweets and you get popping candy. ‘When added to beverages, it gives them their fizz. In the case of a CO 2 shortage, could learners prioritise which industries should have access to the CO 2 supply?īeing thermodynamically stable, heavier than air and with no liquid phase at atmospheric pressure, CO 2 is one of the most useful industrial gases we have, says Mark Lorch, head of chemistry, biochemistry and chemical engineering at the University of Hull. Learners should be able to recall the processes by which carbon dioxide moves into or out of the atmosphere. Ask learners why it might be difficult to extract carbon dioxide from the atmosphere for use in industrial applications. Discuss some examples of carbon dioxide usage in industry from this article. ![]()
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