Sealing challenges in the solar power industry
Solar power is one of the fastest growing renewable energy segments world-wide with its unique sealing challenges. The applications are characterized by a combination of high temperatures and very aggressive media. In this field traditional material selections reach their limits and only advanced materials and designs help end-users sealing molten salt systems effectively.
Challenges
- Graphite is often the preferred choice, when high temperature applications have to be sealed. However, when graphite comes in contact with molten salt at elevated temperatures it creates a chemical reaction (oxidation)
- Molten Salts are very corrosive
- The melting point of mixture is approx. 220°C, below that temperature, it solidifies
BPG 7829 Solar Set
There are a number of components in CSP plants such as heat exchangers, pumps, valves, flanged connections that requires adequate sealing. In order to address the sealing challenges in these industrial-scale installations Burgmann Packings offers a wide array of sealing solutions for molten salt service. BPG 7829 Solar Set is designed for the use in molten salt applications.
The packing set combines latest material science with special engineered material set up. BPG 7829 is made of a unique combination of engineered components. The bottom of the set is additionally equipped with a metal cap to protect the set against aggressive or oxidizing media. The metal cap at the top will protect the set against influence of the atmosphere at high temperatures. The core of the set features an advanced sealing material composition with progressive low-friction impregnation which additionally protects the set against aggressive media. Furthermore, the set is supported by intermediate, mineral-based high-temperature barrier discs which create a reliable low leakage sealing solution.
Concentrated Solar Power Plants
In the area of conventional fossil power plants, liquid salt storage systems have the potential to make them more flexible by integrated heat storage or to convert them into heat storage power plants. In solar thermal power plants, liquid salt storage systems are already in commercial use for demand-driven power generation often used at elevated temperatures.
Within the Concentrated Solar Power plant (CSP) the concentrated sunlight heats molten salt to over 530°C. The heated molten salt then flows into a thermal storage tank where it is stored, maintaining 98% thermal efficiency, and eventually pumped to a steam generator. The steam drives a standard turbine to generate electricity. A CSP tower with eight or 10 hours of molten salt storage is currently much cheaper than a solar PV farm with an equivalent amount of lithium-ion batteries.
In the case of fluctuating power generation from renewable energies, molten salt reservoirs can be used in power plant technology to stabilize volatile renewable electricity. Furthermore, the fields of application include energy-intensive industrial processes such as the production of steel, iron, non-ferrous metals, glass, cement or chemical products. Liquid salt storage can increase energy efficiency in these processes.
