NUS engineers invent a way to store natural gas in solid form in just 15 minutes

Good for Singapore's energy security.

Sulaiman Daud | December 03, 2020, 01:00 PM

The smart cookies at the National University of Singapore (NUS) have done it again.

A team of engineers from the Department of Chemical and Biomolecular Engineering at the NUS Faculty of Engineering, led by Assoc. Professor Praveen Linga, have invented a way to make transporting natural gas an easier process.

Their new method (which should be given a cool name, like the Solidifier), converts natural gas into a non-explosive solid by adding a low-toxicity additive mixture they invented.

This process takes place in just 15 minutes, according to a Dec. 3 press release from NUS.

So how did they do it?

The NUS team duplicated a naturally-occurring process that turns natural gas into solid gas hydrates. Water molecules form "cages" that trap natural gas molecules, forming a solid substance known as combustible ice.

However, this process usually takes millions of years to occur naturally, according to research fellow Gaurav Bhattacharjee, who also worked on the project.

Previously, researchers have found ways to speed up the process. But they did so using highly toxic substances that were unsafe for the environment and the people exposed to them.

But the NUS team used a substance known as L-tryptophan, which is an essential amino acid in human diets. The muscle-building amino acid somehow also speeds up the caging of natural gas molecules into solid hydrates.

The new additive mixture is the fastest-working one to date, more than twice as fast as existing standards, while also being less toxic both for the environment and people.

Why does it matter?

Right now, natural gas for commercial use is usually stored in liquefied form at about -160 degrees celsius, compressing it to almost 250 times atmospheric pressure.

This is neither cheap nor safe to store for a long period of time.

And the issue is particularly relevant to countries like Singapore, where 95 per cent of energy needs comes from natural gas.

But with the NUS method, natural gas can now be stored at just -5 degrees celsius, and at normal atmospheric pressure. The conditions are similar to the average home freezer.

This would make storing natural gas much easier. According to the press release:

"The NUS researchers are now aiming to convert larger volumes of gas into smaller volumes of solid at a pilot scale of 100 kilogrammes per day. If successful, this will enable the commercial adoption of the solidified natural gas technology and create a solid that is stable to store at atmospheric pressure. They hope to eventually scale it up for industrial use."

The research was funded in part under the Energy Innovation Research Programme (ERIP), which is administrated by the Energy Market Authority (EMA) and funded by the National Research Foundation (NRF).

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Top image from NUS.