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Refrigeration could cool down the cost of carbon capture and storage

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April 22, 2014

New research by Sintef scientists has found that refrigeration technology may reduce cost ...

New research by Sintef scientists has found that refrigeration technology may reduce cost by up to 30 percent (Photo: Shutterstock)

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For years carbon capture and storage (CCS) has been considered a costly but necessary step in reducing emissions and protecting our environment. New research by Scandinavian research organization Sintef has found that refrigeration technology may reduce costs by up to 30 percent, increasing the potential for faster implementation.

“We were able to show that there are a number of important potential improvements to be made in the process,” says Sintef research scientist Kristin Jordal. “That said, cold CO2 capture turned out to be one of the most promising technologies.”

So how does it work? Refrigeration of flue gases from large power stations and industrial plants causes the CO2 compounds to condense into liquid form. This liquid can then be transported through pipelines, in tanks, or on boats. The research suggests that this could use less energy than approaches that use chemicals or advanced materials to extract CO2, and could potentially decrease the cost to transport the carbon.

“CO2 captured in liquid form can be loaded straight aboard a vessel and be transported to offshore storage sites before pipelines have been laid,” says Jordal. “If our findings open up the possibility of cold CO2 capture, they could help to bring forward the introduction of CO2 storage beneath the North Sea.”

Core participants in the “Cold CO2 Capture” project discuss their results. From the left; ...

Core participants in the “Cold CO2 Capture” project discuss their results. From the left; chief scientist Petter Nekså, research scientist Kristin Jordal and David Berstad, MSc, all of SINTEF Energy Research (Photo: SINTEF/Thor Nielsen)

Beneath the North Sea you’ll find what is known as the Sleipner field, an area where around 11 million tons of CO2 has been injected since 1996, according to the British Geological Survey. The area has the potential to hold an unimaginably large amount of CO2. The British Geological Survey estimates its pore-space volume at 6 x 1011 m3, where 1 percent of that space could hold 50 years worth of emissions from 20 coal-fired plants.

The looming concern is what happens if the CO2 leaks? If CO2 were to be absorbed into the water, it would increase the acidity, potentially damaging the eco-system. In the interest of monitoring the movement of CO2 there have been six 3D seismic surveys completed. The most recent was done in 2008, and all have shown that the CO2 has remained securely in the shale below the sea.

Proponents suggest that CCS would be able to minimize our carbon output and its effect on green house gasses. The Intergovernmental Panel on Climate Change (IPCC) has maintained in its latest report and summary released on April 13, that implementing CCS on a global level is an integral step in protecting our atmosphere. The IPCC asserts that in order to create a scenario in year 2100 where we are likely to keep temperature change below 3.8° F (2° C), which is in line with the pre-industrial levels, CCS will need to play a key role in reducing emissions globally by 25-55 percent compared with 2010 emission levels.

Sound too good to be true? It might just be

Unfortunately, even in the ideal circumstances, CCS is not going to solve our climate challenges in the long term. Lets say CCS, as part of a portfolio of other emission-reducing technology, is successful in removing enough carbon in a timely manner to neutralize our species’ footprint. Eventually, there won’t be anywhere left to deposit the carbon. If we haven’t embraced renewable energy on a widespread scale by then, we’ll be back at square one.

And that’s only if the technology is in place in a timely manner. According to the Global CCS Institute, it can take 5-10 years to prepare a storage site for the collected carbon. This means that if a project commences today, it will be hard pressed to be storing carbon before 2020. As Kyle Sherer pointed out in his 2008 review of CCS, it was already questionable if there was enough time to effectively implement the technology six years ago, and today there are only 12 industrial scale CCS operations as opposed to the more than 2,300 coal-fired power plants identified by the IEA Clean Coal Centre.

The potential viability of refrigeration in CCS is an important step to overcoming cost and energy hurdles in the way of implementing carbon capture technology, but it will only be useful if companies and governments work together quickly to build the infrastructure required, so that researchers can move on to spending their time on more long-term solutions.

Sources: Sintef, ZEP

About the Author
Meg Alexander Meg Alexander started traveling around the world in 2014, and the road led her straight to Gizmag. As a child, she annoyed her family by asking "why?" and "how?" incessantly, and she hasn't stopped since. Coming from a long family line of journalists, it's only natural that she now formulates the answers she finds into articles.   All articles by Meg Alexander
6 Comments

Las time I looked, the CO2 went to liquid state only at 5.11 atmospheric pressures or above. At normal pressures it goes stright to solid state making it a bit difficult to pump (pun intended). So one has to compress the gas significantly before proceeding with liquification. Which in turn adds energy to the gas making cooling even more difficult.

To make long story short - I don't believe ever that any industrial player would invest in such an apparatus. It's easier to buy more CO2 quote.

Kaido Tiigisoon
23rd April, 2014 @ 03:47 am PDT

When the Feed CO2 concentration is sufficiently high (eg > 60%), pursuant to the so-called Inverse Lever Rule CO2 can indeed be captured via refrigeration with a very low energy and capital cost.

In fact, in the Permian Basin area of West Texas, for more than thirty years CO2 has been separated by refrigeration from natural gas produced in the context of longstanding Enhanced Oil Recovery programs. The largest of these refrigeration plants separates more than five million tons of CO2 each year. This is therefore a fully-proven process which importantly has a high tolerance of SO2 – an important consideration for CO2 capture for a coal-fired power plant. By comparison, the amine capture process currently favored for CCS has only rarely exceeded 1.5 million tons/year of capacity at a single plant, and has a tolerance of SO2 of just a few ppm – a level that has never been scrubbed to by any known commercial process on a sustained basis (for a short duration pilot test the amine solution can of course be repeatedly replaced, which is very expensive and creates an awkward environmental disposal problem).

Quite separately, in the Permian Basin gas separation membranes have also been used for more than thirty years to increase the CO2 concentration. The largest of these plants processes more than ten million tons of CO2 each year, so this is another fully proven process (which again has a high tolerance of SO2).

Moreover, in more than one plant gas separation membranes and refrigeration are used together at the same location in an optimal way. It therefore seems that the Gas Processors are very far ahead of the people Brussels who provide funding.

I have been studying these plants (and many others of direct relevance to CCS and beneficial CO2 use) in detail for more than seven years now. Their performance is impressive, and it is quite surprising they have not been embraced for CCS. If you would like to learn more about these plants and their implications for low cost CO2 capture and beneficial use, please find me via LinkedIn: David Willson, Stanbridge Capital.

Methanogen
23rd April, 2014 @ 08:44 am PDT

Why not use solar or wind energy to separate the captured CO2 into carbon and oxygen instead of storing it? I can imagine plants for this in areas where it is mostly sunny or windy the year round so you have energy for the process. Jobs are made, raw materials for other industries are created and the environment is helped along the way.

MK23666
23rd April, 2014 @ 10:01 am PDT

Methanogen's idea sounds good.

My idea is to make it a marketable product. Find a way to better store and ship it then ship it to the algae farms that are producing gas. Find a way to make electronics out of them using the new carbon method. Discover that it's actually beneficial to put some of it in some forms into the ocean. Make an x prize to find more uses of this product.

Ben Tumaru O'Brien
23rd April, 2014 @ 01:42 pm PDT

Or you could just bubble the emissions through water to dissolve the carbon dioxide and then grow alga in it to make animal feed and diesel fuel.

JoejustJoe
23rd April, 2014 @ 06:49 pm PDT

Some of the first machines have a marvelous way and efficiency at removing CO2 from the atmosphere.

Like all first machines, these things are rather large in size.

They actually self-replicate when given enough solar energy, soil, and water.

They're called Trees. They require no pay. They cost nearly nothing.

And scientists are still marveling at their engineering processes.

Daniel Gregory
24th April, 2014 @ 07:09 am PDT
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