Lessons Learned With Valve Design, Commissioning, and Testing at the STEP 10 MWe sCO2 Facility

Valves are one of the most important pieces of equipment in fluid systems, with their usage helping perform all aspects of operation and assisting with overall maintenance. Designing valves for severe service is a demanding task but designing them for supercritical CO2 (sCO2) can be even more challenging. With limited design and material guidance and a lack of industry expertise for large bore sCO2 valves, manufacturers often rely on previous design and experience from severe service, such as that of steam applications, which may not be suitable in this field. This paper aims to highlight the physical and technical challenges of valves through the design, commissioning and operation of large-scale sCO2 processes at the DOE STEP facility, providing detailed lessons learned from addressing these challenges. It discusses how the deficiencies identified were mitigated for project success, including aspects of mechanical design, controller, and material modifications. These lessons emphasize the importance of material selection, testing, and close monitoring of novel components through commissioning and nominal operations. This approach ensures optimal equipment operation and gathers information on whether changes will need to be performed for successful operation and longevity of these mechanical devices.