ClearSign Burner Demonstrates Flexible, Low-NOx Fueling for Industrial Operations

ClearSign Technologies Corporation, with NETL project management support and funding through the Small Business Innovation Research (SBIR) program, recently demonstrated its revolutionary process burner in front of a live industry audience at the Zeeco test facility in Broken Arrow, Oklahoma. The burner successfully operated on fuels ranging from 100% natural gas to 100% hydrogen while keeping nitrogen oxides (NOx) at ultra-low levels (under 5 parts per million) without any post-combustion treatment.

Industrial process burners are foundational to U.S. refining and chemical operations because they supply the heat powering nearly every facility in the country. Operators routinely have access to hydrogen-rich refinery off-gases or other mixed gas streams that provide low-cost fuel, but access remains untapped due to limitations in existing burner technology.

"ClearSign's project was designed to solve this challenge by delivering fuel flexibility throughout a full operating range with ultra-low NOx performance," said NETL's Drew O'Connell, who managed the project. "Their success is the kind of outcome the SBIR program is designed to produce - moving from prototype to successful industry demonstration in under four years, underscoring how a small-business-led innovation can strengthen U.S. industry and domestic energy systems."

ClearSign achieved their project goals through their proprietary burner design that uses a novel partial pre-mix of air and fuel, leading to greater optimization. Over the course of the project, ClearSign iterated that design - in partnership with testing partner Zeeco - to ensure the burner would scale and operate reliably in real-world conditions while holding to the program's ultra-low NOx performance specifications.

"Hosting the ClearSign demonstration at our test facility let us put a development project through the same witnessed-test discipline we use for any commercial burner program. The unit operated cleanly across every fuel and every load we asked of it during the demonstration, and we look forward to continuing to work with ClearSign and NETL as the technology moves into field deployment," said Darton Zink of Zeeco.

This multi-year SBIR effort produced burner hardware, a design-iteration history, and a multi-window dataset across two burner sizes, serving as a springboard for the next commercialization step: installing the ClearSign burner in an operating customer facility. The demonstration was deliberately structured to give the prospective host-site community a direct, hands-on view of the technology and to accelerate the path to field deployment.

Beyond emissions performance, the burner is designed to retrofit into most existing process-heater installations. Internal flue gas recirculation, fuel-lean premixing, and a patented distal flameholder - all packaged inside a compact burner head - control flame chemistry directly, without selective catalyst reduction or any other bolt-on aftertreatment. No other commercially available burner has demonstrated this combination of ultra-low NOx performance, ease of use and operational flexibility across the complete natural-gas-to-hydrogen fuel composition range, and ClearSign is now extending the same engineering methodology to a broader range of burner sizes and configurations to cover the full process-heater market.

"In addition to developing a burner technology capable of meeting the strictest U.S. air regulations, our objectives for this project were to provide a product that was easy to install and use for operators, and that is provided to our customers, and operated in a manner consistent with industry norms. The outcome is an emissions control solution that is both cost efficient for our customers and provides ClearSign a robust technology platform facilitating expansion into wider refining and petrochemical processes," said Jim Deller, chief executive officer of ClearSign Technologies.

NETL is a U.S. Department of Energy (DOE) national laboratory dedicated to innovating and accelerating the nation's energy solutions in hydrocarbons, geothermal energy, and critical minerals production. The Lab further strengthens its impact by engaging with industry, academia, and other stakeholders through four strategically located Centers of Excellence: Coal, Critical Minerals and Advanced Alloys, Oil & Gas, and Geothermal. With research sites in Albany, Oregon; Morgantown, West Virginia; and Pittsburgh, Pennsylvania, NETL operates as one laboratory to create advanced energy technologies that support DOE's mission and enable affordable, reliable, and secure energy to fuel human prosperity.