Tagged: carbon dioxide

Turning CO2 into ethanol: is this the new hydrogen?

Last week my facebook feed nearly overflew with shares of an amazing discovery: a group of US scientists of the Oak Ridge National Laboratory in Tenessee had accidently stumbled upon a catalyst that turns CO2 into ethanol. For those of you unfamiliar with catalysts, they are materials or substances that speed up or slow down the rate of a chemical reaction by providing a ‘reactive site’. The catalyst itself is not altered during the process (don’t run away, the article won’t get more complicated than this ;) ).

Well well, I thought. It’s about the fourth or fifth time this year I read about a new technique to suck CO2 out of the air. This one sparked my interest more than previous discoveries, though. (more…)

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The ABC of climate change: Carbon Capture Storage

Carbon Capture Storage (CCS) is an integrated set of technologies that prevent carbon dioxide from being released into the atmosphere during the combustion of fossil fuels. It is mainly mentioned in the context of large power plants running on coal, gas or biomass.

There are three main steps to avoid CO2 escaping into the air:

  1. Seperate the carbon dioxide from the other exhaust gases
  2. Compress and transport the CO2 via pipelines to a suitable site for geological storage, typically salt caves, old mines etc
  3. Inject the CO2 deep underground, often at depths of more than one kilometer
Graphical representation of the Carbon Capture and Storage process (graph: University of Nottingham)

Graphical representation of the Carbon Capture and Storage process (graph: University of Nottingham)

CCS is not a new technology and has been applied since the mid nineties, although the amount of CO2 captured and stored remains marginal.

Carbon Capture and Storage got renewed attention when the IPCC’s latest progress report (fall of 2014) announced that the technology was crucial if we want to limit Earth’s temperature rise below 2°C by 2100. They estimated that big emissions cuts would cost more than double when not applying CCS technologies.

Although some say that CCS will allow us to keep consuming fossil fuels at an increasing rate, that is not really true. The processes itself are energy intensive so the overall efficiency of the energy generation process including the carbon capture goes down significantly. In addition, there are concerns regarding the long-term storability and possible leakage of the CO2 out of the caves and rock formations.

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The ABC of climate change: Atmospheric lifetime

The atmospheric lifetime of a greenhouse gas refers to the approximate amount of time it would take for the anthropogenic increase (i.e. increase due to human behavior) to an atmospheric pollutant concentration to return to its natural level. That can happen as a result of either being converted to another chemical compound or being taken out of the atmosphere via a so-called sink. The lifetime depends on the pollutant’s sources and sinks as well as its reactivity.

The lifetime of a pollutant is often considered together with the mixing of pollutants in the atmosphere –a long lifetime will allow the pollutant to mix throughout the atmosphere. Average lifetimes can vary from about a week ( e.g. sulfate aerosols, small particles in a gas) to more than a century (e.g. carbon dioxide). The chart below shows the atmospheric lifetime of four common greenhouse gases.

In the graph you see that carbon dioxide is hanging around in the atmosphere for quite a long time after we emit it, longer than other greenhouse gases like methane. But you may have heard people talking about methane being 20 times or even 50 times stronger than carbon dioxide. Such statements are quite misleading without further clarification. In fact, that’s the reason why scientist have come up with something called the Global Warming Potential, which looks at the overall effect of a greenhouse gas over the timespan of 100 years after it has been emitted. Even though methane has disappeared after 12-15 years, the net effect is still 23 times stronger than carbon dioxide!

Source

 

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Photo of the week: Rabbit gut microbes to clean up steel production?

If ArcellorMittal's pilot project to turn CO into bio-ethanol turns out economiccaly viable, it will apply the technology in all its steel production plants, such as this one in Bremen (photo: JesterRaiin)

Steel is still the most important engineering material, with a yearly production of around 1,7 billion tonnes. Unfortunately, the process to produce steel starting from iron ore is heavily polluting the atmosphere. Both CO and CO2 are produced, with the first one often burned to produce CO2 as well. When you do the math, you find that for each ton of steel, roughly two tonnes of carbon dioxide are emitted. The contribution of the steel industry to the global CO2 emissions is estimated to be around 5%.

Reason enough to investigate the possibilty of reducing the footprint, thought bioengineering company LanzaTech. They developed the Clostridium microbe based on rabbit gut microbes, to capture carbon monoxide and converting it to ethanol.  “What we are talking about is turning an environmental liability into a financial opportunity,” said Jennifer Holmgren, chief executive of LanzaTech. The ethanol can be used to fuel cars and airplanes. ArcelorMittal, the world’s biggest steel producer, is about to start a pilot project in their production faciliy in Ghent, Belgium to test out the technology. When completed in 2018, the facility will produce up to 47 000 tonnes of ethanol. It’s estimated that for every ton of ethanol, carbon dioxide emissions are reduced by 2.3 tonnes. When the conversion process proves to be economiccaly viable, the company will roll out the technology in all her facilities over the world.

If ArcellorMittal's pilot project to turn CO into bio-ethanol turns out economiccaly viable, it will apply the technology in all its steel production plants, such as this one in Bremen (photo: JesterRaiin)

If ArcelorMittal’s pilot project to turn CO into bio-ethanol turns out to be economically viable, the company will apply the technology in all its steel production plants, such as this one in Bremen (photo: JesterRaiin)

Sources
LanzaTech
TheGuardian
MIT

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Photo of the Week: a loaf of bread will be smaller in 2050

What in heaven’s name has climate change to do with the size of a loaf of bread? Well, probably more than you would assume. Scientists of Australian company AgFace (short for Australian Grains Free Air CO2 Enrichment facility) are investigating the influence of higher levels of carbon dioxide in our atmosphere on agricultural crops like wheat. The effect on grains is complex. Although the plants grow faster, they contain less protein. And apparently it also alters the viscosity of dough and how a loaf of bread rises, as can be seen in the picture below. The smaller loaf was baked from grains that were grown in carbon dioxide levels around 550ppm, the expected level by 2050 (we’re hovering around 400ppm, 350ppm is generally accepted as being the limit to avoid serious climate disruption). The larger one is made from the same amount of wheat, grown in today’s conditions. AgFace is investigating breeds which would reduce the loss of protein content. If this could be achieved, there is at last a positive side at high carbon dioxide levels in our atmosphere.

Higher levels of carbon dioxide affect the amount of proteins in grains, as well as the dough's elasticity and rising process resulting in a smaller loaf of bread (photo Simone Dalton)

Higher levels of carbon dioxide affect the amount of proteins in grains, as well as the dough’s elasticity and rising process resulting in a smaller loaf of bread (photo Simone Dalton)

Source
Sydney Morning Herald

 

 

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