By Paul-Emmanuel Just and Karl Stephenne on Jul 8, 2020
For over a decade, Shell researchers and engineers have worked towards solutions to reduce the carbon footprint of fossil fuels used for energy production. These solutions can be applied by energy producers to meet current and anticipated CO2 emissions regulations.
One proven method is carbon capture.
To lower the carbon footprint from the combustion of various fossil fuels, Shell has invested in carbon capture technologies, including Shell’s CANSOLV CO2 capture. CANSOLV CO2 capture technology targets low-pressure streams for both pre- and post-combustion applications.
To learn more about the development, implementation, and future applications of Shell’s CANSOLV CO2 capture, we spoke with Dr. Paul-Emmanuel Just, the research and development team lead for CANSOLV’s DC-103 solvent, and Karl Stephenne, the lead process engineer behind the deployment of two Shell CANSOLV licensed plants in Canada and South Africa.
Q: Could you tell us about the development of Shell’s CANSOLV CO2 capture?
Paul-Emmanuel Just: About 15 years ago, I started working as a chemist at the company that began the development of the CANSOLV technology prior to its acquisition by Shell. They were developing solvents for SO2 scrubbing and wanted to get in the business of CO2 scrubbing.
For CO2 capture, in the early days and after we were acquired by Shell, we experimented with several solvents. We started in the lab with very small units to screen for several different solvents. When we found a good solvent in terms of energy-intensity and stability, we would go to sites to conduct piloting campaigns and test the robustness of the new solvents on real flue gas.
We’d have a small pilot unit installed in a type of marine container you see on ships. For two to three months, we would have a mini-Cansolv unit in this container, and we would plug it in the exhaust at various sites, like a coal-fired power plant or a gas-fired power plant, to test solvents in various conditions for stability and energy efficiencies. We travelled to Norway, the U.S.A., and Canada, testing these new solvents.
We learned a lot from our trials. We would go back to the lab, back to the drawing board, and try to improve our product. One issue we had when scaling up from the lab to the real flue gas pilot test was the compatibility of solvents with real-life applications, for instance with the impurities in the flue gas we were trying to treat.
We could not simulate impurities in the lab, as we were always working with clean gas. We brought our experience with the real-life operation back to the lab in order to make the product more robust. There was a lot of back and forth until we came up with the DC-103 solvent that was really strong.
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Designing the Pilot Plant
Karl Stephenne: When I was hired to work on the CANSOLV process in 2004, they were testing CO2 capture technology in the lab. They needed a pilot plant to test it at a larger scale and at client sites. They asked me to design and build a pilot plant. I was really excited by the mandate. I saw this as an opportunity to work for a company with environmental technologies.
We came up with the design of a 40 ft-long modularised mobile unit that fits in a standard marine shipping container. We fit in all the process equipment, including the very high towers that we would pull out of the container and mount on top once on site.
We travelled with this mobile unit and tested CO2 capture technology around the world. At first, we worked with companies looking to invest in reducing the carbon emissions of coal, and we helped them develop carbon capture solutions.
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Testing the DC-103 Solvent at Demonstration Scale
Paul-Emmanuel Just: After the on-site piloting phase, we conducted testing at a demonstration test centre in Alabama, called the National Carbon Capture Center (NCCC), where we tested our solvent with much bigger machines. They can process anywhere from 5 to 20 tonnes of CO2 capture per day.
The demo scale, though larger than our pilot test, was still about 50 times smaller than the real application would be. We went to the Technology Centre Mongstad (TCM) in Norway to conduct larger runs (up to 100 tonnes of CO2 captured per day) to test our solvent. When this was successful, we were confident we had a good product that we could put on the market.
Typically, the development timeframe from when you test your solvent in a beaker in the lab until you can put it on the market takes about 7 to 10 years. It can seem long, but it was relatively fast for deployment on such a large scale.
Q: How did CANSOLV SO2 capture inform the development for CANSOLV CO2 capture?
Paul-Emmanuel Just: Our development for CO2 capture was based in large part on our learnings from SO2 capture. The chemistry is relatively similar between SO2 and CO2, and they both react in similar ways with solvents. The biggest difference is about energy savings.
Let’s say for a power plant to remove CO2, the amount of CO2 is so large that it may consume up to 40% of the energy produced just to try to capture the CO2. It wouldn’t make sense. So a large part of our work was focused on creating a solvent that would consume the least amount of energy possible.
There was a trade-off between the solvent’s energy intensity and stability. We had an experience where we’d developed a very good solvent that didn’t consume a lot of energy, but unfortunately, it wasn’t very stable and fell apart rapidly. I believe with the CANSOLV DC-103 solvent, we found the best of both worlds: very low energy consumption and a very stable blend.
Q: What did the Shell Catalysts & Technologies team learn from the first commercial applications of CANSOLV CO2 capture?
Karl Stephenne: CANSOLV initially was targeting the coal industry for both SO2 and CO2 capture technologies. But there are more opportunities emerging for CO2 capture from natural gas. In Canada, for example, coal is being phased out by the government and the natural gas market is expected to grow significantly over the coming decades.
The first large-scale deployment of CANSOLV CO2 capture was a project in Saskatchewan, Canada, which was funded, to some extent, by the Canadian government. I was the lead process engineer and the technical interface with the detailed engineering firm. We worked through all the challenges together and when we ran a performance test, we were satisfied by the unit’s performance.
The project owner had the ambition of deploying carbon capture in more units. They wanted to build in-house expertise, so they took on the responsibility of commissioning the plant. We’ve maintained an ongoing relationship with them to ensure the optimal performance of the unit.
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Natural Gas Combustion Application in South Africa
Karl Stephenne: We also worked on a very successful project in South Africa. The kick-off meeting to the unit start-up took only about two years. I was the project manager as well as the lead process engineer.
It was an application that was easier because natural gas combustion is not as contaminated as a coal-fired application. We collaborated very effectively with the engineering firm for the detailed design. They were committed to making this project a success. The project started up in 2013, and this was rapidly followed by a successful performance test run, and everyone was satisfied by the application.
Q: What are the current and future applications for CANSOLV CO2 capture?
Paul-Emmanuel Just: We found a very good solvent. Not only among Shell CANSOLV researchers, but other developers have also tried over the past ten years to develop better solvent formulations.
We are now at the very bottom of the thermodynamic minimum, so I don’t think we can come up with solvents that will be better in terms of energy intensity. There will be some fine-tuning, but most of the chemistry has been sorted out.
Most of the improvements will come from smarter designs and engineering — the construction of the Shell CANSOLV unit and how to save costs with materials, the modularisation of equipment, and with replication.
Lowering the carbon intensity of low-pressure flue gas
Karl Stephenne: Shell has changed the face of the natural gas industry significantly with Shell gas reserves and liquified natural gas (LNG) technologies. In some parts of the world, power production using gas is now a better commodity. But it’s still carbon intensive — around half that of coal when used to generate electricity — but still more than renewables.
Shell wants to help make natural gas more sustainable, and carbon capture technology can be a part of the solution.
Editor’s note: Shell has announced an ambition to be a net-zero emissions business by 2050, in step with society. We intend to work towards this ambition in three ways: through our aim to be net-zero on all the emissions from the manufacture of all our products, through our aim to reduce the carbon intensity of the energy products we sell, and through our aim to serve as a decarbonisation partner to our customers.
Shell’s CANSOLV team is working across Shell to help lower emissions. Shell is also looking to sell more lower-carbon energy products such as renewable power, biofuels, and hydrogen over time in step with our customers’ needs and preferences. Our ambition also means working together with our customers to address emissions as a result of continued demand for oil and gas, through both natural processes such as reforestation, as well as technology to capture and store away CO2.
And while our business plans today will not get us to where we want to be, we want to play our part and contribute to the global effort to tackle climate change as we provide energy the world needs. We intend to remain in tune with society as it works towards the goals of the Paris Agreement. CANSOLV CO2 capture technology will continue to be an important and strategic option in a wide array of solutions for both Shell and our customers.