Renewable energy is one of the fastest-growing energy sources in many well developed as well as developing countries, with solar energy becoming increasingly popular for generating electricity or heating and desalinating water. The solar thermal power plant industry is driven by the efficiency of the media and the ability to retain heat through the process for maximum output of steam, and in turn, the generation of power. As part of the process of improved heat efficiency, media technology has developed to the use of molten salts at elevated temperatures, which are notably corrosive (60% NaNO3 + 40% KNO3), oxidising and abrasive. The ability to seal these salts, particularly with respect to service life and minimised down time, is a significant factor that contributes to overall process efficiency.
As temperature demands are increasing, the market demands are for more advanced, superior sealing options. As a result, cutting edge material technology has been constantly evolving in conjunction with new, unique stem sealing system constructions designed specifically to withstand a very harsh environment with the ultimate target to maximise stem packing service life and ensure effective sealing performance.
James Walker’s level of expertise in compression packing can help customers in the solar energy sector meet their valve sealing challenges in critical, high temperature applications thanks to the latest addition to the Supagraf® range. The company’s experience in packing development and manufacturing, alongside collaboration with valve Original Equipment Manufacturers (OEMs) and test houses, as well as end users and well-known EPC companies experiencing significant sealing challenges of molten salt, have been the key success factors driving the development of the most advanced packing solutions.
This work has seen the development and now launch of Supagraf® HT – designed specifically for ultra-high temperature applications, and with the ultimate goal of minimising leakage and maximising service life whist simultaneously improving the ease of valve maintenance for customers. The product also provides other important benefits, such as improved health and safety through reduced housekeeping and maintenance needs in concentrated solar power plants, as well as a reduction of product loss (molten salt) in the system, significantly improving operational efficiency through a reduced total cost of ownership.
“I am pleased to be able to expand the Supagraf® range with this new addition, enhancing our product portfolio to include Renewable Energy, which is one of the fast growing sectors and of strategic importance to our business. As you would expect from James Walker, Supagraf® HT is a new packing solution designed using state-of-the-art, cutting edge technology. Specifically intended for valve applications handling high temperature molten salt up to 650°C, the product consists of a set of rings made from a unique combination of engineered components in an innovative configuration, with excellent chemical and corrosion resistance to withstand the harsh environment. Such a design enables the product to seal the media from external atmosphere as well as protect the sealing elements in the packing set from aggressive, ultra-high temperature and abrasive molten salt. The way these materials are combined, positioned against media side and atmospheric side, supported by some innovative elements, plus depending on the valve type they have been designed for (rising stem valves – gate, globe valves or quarter turn valves – butterfly valves), ensure customers with critical valves handling high temperature molten salt have a mechanically and thermally stable packing solution that covers pressure classes from Class 150 up to Class 600.”
Jakub Marczyk, Global Product Manager for Gaskets & Compression Packing at James Walker
