Don't Be Complacent About Amine Use in Carbon Capture

2022-10-03 original Engineering

Amine-based solvents are widely used in current commercial-scale CCS (Carbon Capture and Storage) plants, and I had personally accepted this without particular question or concern.

I knew efforts to replace them were underway, but honestly I had never given any thought to the toxicity angle (I simply didn’t know about it), so I’m putting together a summary here, more or less as a memo.

Here’s my summary of what’s written in this article:

“What Is the Impact of Amine Emissions?“https://www.envirotech-online.com/news/gas-detection/8/breaking-news/what-is-the-impact-of-amine-emissions/58352

Amines are extremely useful for carbon dioxide removal

Removing carbon dioxide from exhaust gas (mainly from power plants) is an extremely important technical challenge from an energy policy standpoint as well. Processes using amine-based solvents operate at ambient temperature and pressure, which makes them easy to retrofit onto existing plants, and they hold up well enough in terms of cost and efficiency too.

At thermal power plants, waste heat can be used to release the CO2, and it’s also relatively easy to secure the energy needed to pressurize and liquefy it for pipeline transport.

So amine-based systems are currently the mainstream approach.

Amine leakage

Amine leakage can occur at various points in the process. It can turn up in exhaust gas, in wastewater, or leak from the components themselves.

And the important point is that no proper regulations govern this leakage.

Because of this, discussion of the purity of the captured carbon dioxide is extremely active, but discussion of amine leakage and its concentration is hardly active at all.

Nitrosamines

Nitrosamines are compounds that can form when amines are released into the atmosphere.

They have characteristics such as:

Extremely low biodegradability (they don’t naturally disappear if left alone)
High toxicity
High mobility (contamination spreads easily)

and can be described as among the worst substances in terms of harm to health and the environment.

However, current drinking water and the like actually contains only very small amounts of nitrosamines, so it is generally considered that there is no need to examine its effects. Because of this, nobody has carried out detailed research into how much impact would result, and at what level, if the concentration of amine-based substances rose even slightly.

Also, because no real regulation exists, there isn’t even measurement data on how much amine is actually being emitted, or at what rate, in real industrial settings.

The IEA holds that, from the standpoint of carbon offsets, CCS plants will need to scale up not by a few times but by several tens of times their current capacity. The IPCC concurs with this view.

But when that time comes, we actually have no idea how much amine these plants will release, or how much environmental damage and health harm will result (or fail to result).

Originally published in Japanese at https://clazytech.com/2022/10/1498/. Translated with LLM assistance and reviewed before publication.