Shell workers completed working on CANSOLV SO₂ standing outside of carbon capture and storage.

Behind Shell Technologies: CANSOLV SO₂ and CO₂ Capture with Devin Shaw

In response to emissions regulations and environmental concerns, plant operators have adopted technologies to remove pollutants like SO₂ and CO₂ from industrial off-gases.

By Devin Shaw on Jul 19, 2020

Shell CANSOLV SO2 and CO2 capture systems use tailored, amine-based absorbents to capture pollutants from various flue gas streams and to produce SO2 and CO2 as by-products that can be sold, reused, or stored.

Currently, the applications for SO2 scrubbing systems are widespread, due to government mandates that limit SO2 emissions from refineries, power plants, and chemical plants. Meanwhile, the applications for CO2 capture remain concentrated to projects where government-backed initiatives are advancing CO2 emissions reduction technology and incentivising carbon storage with tax credits.

With increasing global action from public and private sectors to combat climate change and reduce CO2 emissions, Shell Catalysts & Technologies spoke with Devin Shaw, commercial director for CO2 capture and carbon capture and storage (CCS), to learn about how CANSOLV was developed and where it’s headed.

Q: How did you get involved with Shell CANSOLV technology?

I was hired by the company which began the development of the CANSOLV technology prior to its acquisition by Shell, based in Montreal, Canada. This was back in 2007, right before it was acquired. The company was looking for someone experienced deploying and selling advanced technologies in a commercial setting.

Prior to the acquisition by Shell, the company had some success in selling SO2 scrubbing licenses. They were looking to develop and commercialise the DC solvent, the CO2 capture solvent, which had a very interesting potential future. At the time, it was still in the lab and tested, and wasn’t fully developed or commercialised yet.

Full deployment in the CO2 capture space

The biggest change from when I arrived to now is the full deployment in the CO2 capture space.

The projects that consider large-scale deployment of CO2 capture technologies are quite unique, as they require large-scaled expenditures and a specialised technical base. There are still very few of them globally.

Shell’s acquisition of the technology allowed for CANSOLV’s advanced development and brought additional wherewithal to support large projects. The marketing and access to resources were dramatically increased. Within Shell, we had groups of specialists in every point of contact in the technology, and expanded budget for research and development.

Q: Could you tell us about CANSOLV’s early days?

It started with just four engineers and chemists working in Canada on development of amines for use in the oil and gas industry, including amines specifically tailored to capture H2S and clean refinery gas streams or natural gas streams.

The developers were working in the mid- to late-80s and saw that in the United States specifically, the Environmental Protection Agency (EPA) had significant regulations put in place to dramatically limit the emissions of SO2, which was known at the time to cause acid rain.

Developing an Amine for SO2 Capture

These four guys decided: what better way was there to capture SO2 economically than to use an amine? An amine is a regenerable technology, so you capture your pollutant, in this case, SO2, and then you can separate the pure pollutant and reuse the amine.

Compared to the conventional technology, such as caustic or limestone, which are once-through technologies that absorb pollutants and form another product that is essentially waste — an amine is regenerable and produces a lot less waste. It is more economical in how customers don’t have to purchase 100% of the amine every time they need to capture SO2. They can regenerate it.

That was the original thought back in the 80s; the developers tested the technology internally in the lab, and thought it had a lot of promise. The initial tests of the technology have proven that it was successful, but it still required more efforts to be deployed commercially.

Learn More About Amine Gas Treating

Industry Response to the EPA’s Clean Air Act

Then in 1990, the EPA released the Clean Air Act, and the response from market — which back then was primarily the coal-fired power plant market, and was the biggest polluter of SO2 — was to switch to low-sulphur coal rather than to invest in large-scale flue-gas desulphurisation equipment. That essentially delayed the need to invest in equipment. The SO2 capture technology was promising, but had no commercial value at that moment, and therefore was put on the shelf.

This was when the technology’s four developers presented a business case and a request to buy the technology and take it private.

Q: Could you tell us about the development of Shell CANSOLV DS and DC-103 solvents?

The two solvents are quite similar, but they serve different markets entirely. The DS solvent was initially deployed in 2001, while DC-103 was commercially deployed in 2014. If I were to show you a flowsheet of the two processes, you wouldn’t be able to tell the difference. The amines themselves are slightly different; they absorb different molecules. CANSOLV DS is custom made to target a much more acidic species, SO2, while CANSOLV DC-103 targets CO2, which is more alkaline. They have slight tweaks to them that change performance dramatically, but the main equipment is nearly identical.

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Core Solvent Improved but Retains Fundamental Integrity

Solvents are always in development, but fundamentally, they haven’t changed, and the reason being is that they are very good solvents. We’ve developed different ways to inhibit degradation, to slow down the destruction of amine, which can occur when the gas stream you are treating contains oxygen, and we’ve developed construction in different ways to improve how things work.

We have learnings that come from operating plants. We’ve tweaked the percentages — there are different water contents that you use that affect performances — and over the years, we’ve collected a lot of data to optimise performance even further. But the core solvent itself is still what it was twenty years ago.

Q: What are the current and future applications for Shell CANSOLV CO2 capture?

The world of CO2 capture relies on government regulation and voluntary, corporate leadership in taking on a project, because in almost all of environmental regulations around the world, plant operators have an option to not capture CO2.

This contrasts with SO2 capture applications, where reducing emissions is required for a plant’s license to operate. You cannot emit SO2 or H2S from your refinery, power plant, or chemical plant in most parts of the world; it’s prohibited by law.

Discover H2S to Sulphur Conversion

Future Growth in CO2 Capture and Storage

The issue with CO2 of course is global climate change. We need to get CO2 out of our emissions and not into the air. We have a way of doing that that’s deployed and technically proven, based on technology we’ve been using for many years. But in terms of a commercial context, the application of CO2 capture is not the issue; it’s what to do with the product.

There’s a very limited market that purchases CO2: the beverage and food industry, or plastics, or enhanced oil recovery (EOR). Other than EOR, those are all small volume applications. Moving CO2 out of the atmosphere to the point where it actually mitigates climate change would require capturing a massive amount of CO2 that has no commercial destination. To help limit the impact of climate change, the Global CCS Institute has estimated that more than 2,000 CO2 capture facilities are needed by 2040.1 Currently, the number of large-scale CCS facilities has grown to over 50 around the world.2

CO2 capture relies almost uniquely on government regulations that valorise CO2. As mentioned, there are a few places where this is happening today, but it’s ramping up significantly as governments internationally are coming up with their own carbon schemes. Canada has a carbon tax, the U.S. has the 45Q tax credit, and Europe has a price for carbon that is slated to increase dramatically in the next ten years.3 4 5

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An Ongoing Need for CO2 Management Technologies

It may be that in the far future, we won’t need carbon capture and storage at all because we will have developed an energy source that is not carbon based. It could be through cold fusion, or some kind of technology that generates energy that does not create CO2 as a by-product.

Another path to a lower-carbon energy future may be made possible through energy storage. Instead of needing a new non-carbon based energy source, we could have breakthrough developments in energy storage, such as a new high capacity, lightweight battery, that would enable taking wind, hydro, and solar power from wherever and whenever it is made, store it, and use it on demand elsewhere.

In order to make that kind of future possible, we, as Shell, are constantly investing in CO2 capture technologies and increasing renewables into the energy mix that we provide.

Subsequently, there will also be an increasing need for technologies that manage CO2 and the CO2 capture and storage technologies will continue to play a key role in the energy transition.

Download the Switching to ADIP-X or Sulfinol Fact Sheet to Discover How to Enhance the Economics of Acid Gas Removal