Solvay has just installed a regenerative thermal oxidation process to capture methane from a 500-meter deep shaft ventilating its mine in Green River, Wyoming. It’s the first time an RTO has been used for trona, which Solvay and others process into washing soda or sodium carbonate, an essential raw material for not only detergents, but glass, tires, EV batteries…you name it.
When it comes to emissions, the trona industry has been able to fly below the radar somewhat, avoiding the same scrutiny applied to other industries. While a mine emits large volumes of waste air via ventilating shafts, the greenhouse gas content is relatively small and comprised of naturally occurring methane and some process related emissions. That means flaring and capturing the GHGs was never an option.
There’s a handful of companies that operate in Green River — known as the trona capital of the world — but it’s Solvay’s plot that stands out from the crowd with the 10 RTO modules.
“The RTO is the biggest project we’ve done for a very long time. It’s really driven by the customers,” Solvay CEO Philippe Kehren said in an interview with chemicalESG. “This is why we are the first mover.”
The RTO will cut Solvay’s GHG emissions at a group level by 8%. When the Belgian company expands production by 600,000 tons next year to serve export markets in Latin America and Southeast Asia, emissions will still be down 4%.
The oxidiser already covers a big part of the mine, and the chemical process could be duplicated to remove GHGs from the entire site, Kehren said.
Being a first mover in the chemical industry can be tricky, just ask Air Products’ CEO Seifi Ghasemi. The industrial gas maker is getting blow back from some investors for racing ahead with green hydrogen projects without clarity on off take deals and pricing.
In Solvay’s case, it was customers seeking more sustainable supplies of soda ash that helped drive the project forward. Investors, in the main, get it, CFO Alexandre Blum told chemicalESG.
“The use of RTOs is an innovative approach to improving the environmental impact of soda ash production. It can be a highly-cost effective way to manage industrial emissions – reducing VOCs and Hazardous Air Pollutants,” said Edward Middleton, director at etasca, a London-based energy transition and sustainable chemicals advisory. “They have high heat recovery rates – reducing the need for additional energy or significant incremental operating costs.”
Kehren said one of the challenges was finding the right ceramics to ensure the units would operate long enough to make the project economically viable.
The RTO is the latest step in Solvay’s EU1.2 billion sustainability plan through 2040. It already phased-out the use of coal at its Green River soda ash plant in favour of natural gas.
“Investors, I would say, appreciate the fact that, when we do these type of investments, we do them progressively,” Blum said. “Whatever their personal convictions or investment thesis, they know that it will come at some stage. We try to make the investments profitable even when it’s voluntary.”
There’s no national carbon market in the US but Solvay found a way to valorise the captured emissions in Green River thanks to California, where there is a formal cap-and-trade program and compliance monitoring. Plus, sustainably produced chemicals and materials tend to command a premium, although the size of the markup is a topic for debate.
“I would say it is not enough,” said Kehren. “We need the support of customers and not all of them are ready to support this.”
After discovering a synthetic route to making soda ash some 160 years ago, Solvay is planning another big upgrade.
It’s come up with a new technology that does away with the traditional lime kilns, replacing them with an electrochemical process powered by renewable energy.
“People who are not moving in the direction of sustainability, they progressively get out of the market,” Kehren added. “Purchasing departments will select the ones that are trending in the right direction. Some are less mindful and have been taken out.”