Green ethylene

Ethylene is a major industrial chemical, hitherto produced from hydrocarbons, and producing lots of carbon dioxide in its production.  Polythene/polyethylene is made from ethylene.

The University of Singapore has just discovered a process which produces ethylene from water and carbon dioxide at room temperature, using renewable electricity.

Artificial photosynthesis device developed by the research team

at National University of Singapore (Source: PV Magazine)

An artificial photosynthesis device developed by a team of of scientists from the National University of Singapore (NUS) could provide a greener alternative to current ethylene production, employing a completely renewable energy source, while simultaneously converting CO2 with the help of copper catalysts.

According to the findings published in ACS Sustainable Chemistry & Engineering, NUS achieved an unprecedented 1.5% solar-to-ethylene energy efficiency (the total solar-to-carbon-fuels energy efficiency is 2.9%).

Current industrial production of ethylene employs steam cracking of saturated hydrocarbons at 750°C to 950°C, which translates to an enormous consumption of energy, emitting about two tons of carbon dioxide for every ton of ethylene produced.The process, developed by the NUS team, takes place at room temperature and pressure, with only the use of benign chemical reagents.

The researchers have also added a battery to store excess solar energy, thus ensuring stable and continuous production of ethylene, and are now developing suitable catalysts that can be used in similar systems to produce liquid fuels such as ethanol from CO2 and H2O.

“We believe that our work, which is a product of efforts for the last two years, will play a crucial role to address key challenges in the realization of a scalable artificial photosynthesis system to produce clean fuels sustainably,” said assistant Professor Jason Yeo Boon Siang.

[Read more here]

Think about this: instead of producing two tonnes of CO2 per tonne of ethylene, this process will absorb about 0.8 tonnes of CO2 per tonne of ethylene produced (working from the molecular weights of hydrogen and carbon)  What's more, this process can be developed to produce methane, ethanol and methanol.

Of course, it isn't yet commercial.  And there's no mention of costs.  But in, say, 5 years' time, as it becomes ever more obvious that global warming is intensifying, and the consequences of climate change become more obvious and more serious, technologies like this will be embraced even if they are more expensive, because the costs of global warming will be obviously even greater. 

Years and years ago, The Economist magazine wrote an article after the first oil crisis, saying that it  would lead to a reduction in the oil intensity of economies as all the best brains in the world worked out how to use less oil for the same output.  That actually happened, to such an extent that oil prices then fell, and the decline in oil intensity levelled off.  Now the world knows with great clarity (despite the nightmare of Trump and the Republicans) that we have to slash carbon emissions to zero.  And the best brains in the world are working on it.