Fugitive Amine Scrubbing Using Electrostatic Precipitation (Flexible Funding 2021)

If you’re reading this, you’re probably interested in learning about this project or got lost somewhere on the internet. This was one of those projects that came about from a random idea to a problem presented at the UKCCSRC “what are industries’ needs?” events. I spoke with one of the panel speakers from Petrofac (Chet Biliyok) and started discussing the idea, and a few months later, here I am writing about the outcomes of the project that arose. (Thank you UKCCSRC for funding the idea and turning it into this project)

Amines are compounds that are commonly used in the carbon capture processes to strip CO₂ out of the flue gas. But this CO₂ capture process isn’t perfect as some of the amines can leave the top of the tower as aerosols or vapours – this is called amine slip. When they escape into the atmosphere, they can have negative effects on the environment and human health. In this blog post, I’m going to talk about some ways to prevent fugitive amine emissions.

First and foremost, it’s important to understand where fugitive amines come from. In carbon capture processes it’s often caused by the stripper columns operating conditions not being controlled accurately or it can be caused by a fluctuation upstream of the CO₂ capture step. So, there is potential to reduce amine slip by controlling processes more accurately.

Another way to prevent fugitive amine emissions is to use engineering controls. These are measures that are put in place to prevent or reduce the release of fugitive amines into the atmosphere. For example, some facilities may use a water wash step, where water is sprayed into the top of the CO₂ stripping column to reduce the temperature and coalesce/condensate some of the amine slip. To improve the effectiveness of this water wash step, it’s also possible to add an aqueous acid to the water to produce an acid wash and even a UV light step after that to help further.

Location of the amine electrostatic precipitator relative to the CO2 capture plant

These water wash steps are currently the best available technology, but maybe there’s something better, as even these technologies don’t work under transient conditions. There’s another issue too – environmental limits for amines and their degradation products (nitrosamines) are getting tighter and harder to reach. We are also likely to see regulations get more stringent as carbon capture technology is more widely deployed. This is the reason that new technology is required and why the technology I developed in this project is important.

The aim of this project was to mathematically validate and scrutinise the potential of a new amine slip recovery technology based on wet electrostatic precipitation. The Cranfield University team (Siqi Wang – PhD Candidate, Alek Gonciaruk – Research Associate) were fantastic and jumped straight in, building a MATLAB model to simulate an electrostatic precipitator and setting up the system. We had regular meetings with the Petrofac team (Chet Biliyok and Duncan Harrison) to get input into our boundary and initial conditions, to ensure our model was representative. Petrofac were also heavily involved in critically evaluating the technology, checking facts and helping with the engineering – thank you Duncan and Chet.

The outputs of the modelling and work on the project was generally good news. It definitely threw up some surprises that we weren’t expecting and meant the engineering of the system needed careful thought but, crucially, no showstoppers.

Modelling results of amine ESP showing aerosols moving towards collection plate

Building on from this project, I ran an individual thesis project conducting further modelling at Cranfield University – thank you Potsawee Yiengvanichchakul. This modelling went into even more depth and built on the knowledge gained in this UKCCSRC project. Going further, I was fortunate to secure funding in the UKCCSRC’s Flexible Funding 2022 call to build a prototype system – you’ll be hearing about this soon!

This project was a fantastic start to developing the next generation of amine slip prevention technology and UKCCSRC must be thanked (again) for enabling it. Since starting the project and learning of the issue in detail, I’ve noted the need for other supplementary technology to be developed including actually measuring the amines and their degradation products in the flue gas – no mean feat at the limits the Environment Agency has set.