ClearSign Technologies Corporation (NASDAQ: CLIR) received a purchase order for physical testing and demonstration of burners in the second phase of a 32-burner retrofit project at a California refinery, the company announced May 14.

The project involves installing ClearSign Core burners across two heaters and represents a new flat flame application of the company's technology. Testing will be conducted at Zeeco's full-scale test facility.

"This is particularly exciting as these burners will be another configuration of our new Core 2 technology, a flat flame application, which will further expand our addressable market to include new refining heater types," said Chief Executive Officer Jim Deller.

The order follows an initial computational fluid dynamics and engineering order from the same customer that ClearSign announced on October 7, 2025. The company said the project advancement came after a demonstration event in Tulsa for decision-makers and prospective clients.

ClearSign develops combustion and sensing technologies for industrial emission reduction and efficiency improvements. The company's products are used in energy, chemical, petrochemical, transport and power industries.