High-Temperature Molten Salt Valve Solutions for CSP Energy Storage
Application Description
CSP energy storage projects generally adopt a “tower/trough concentration + molten salt thermal storage” configuration. Molten salt is heated to about 565 °C in the solar field; its flow is controlled by molten salt control valves and shut-off valves; and it is then stored in thermal storage tanks. When power generation is required, the molten salt passes through a heat exchanger to produce steam that drives the turbine-generator set. The down-tower molten salt high-differential-pressure control valve is the most critical piece of equipment, operating under the harshest conditions in this application.
Application Focus
1. Down-tower molten salt high-differential-pressure control valve: under a large differential pressure the valve vibrates severely, is prone to control sticking and makes downstream pressure control difficult, and it carries a serious risk of molten salt leakage.
2. Molten salt shut-off and control valves: molten salt crystallizes easily, causing salt build-up in the valve cavity and blockage of the flow passage; the medium reaches 565 °C and is highly corrosive.
3. Molten salt butterfly valves: subjected to high temperature and pressure and to frequent thermal cycling and start/stop operations, the sealing structure is prone to failure.
Solution Overview
1. To overcome salt build-up in the valve cavity, a straight-through flow passage has been developed. The highest point of the valve cavity passage is kept flush with the lowest point of the pipeline, so that no salt is deposited inside the cavity.
2. To address vibration and cavitation in the high-differential-pressure control valve, a combined circulating-convection disc trim is adopted. The fluid is turned and made to collide inside the disc stack, achieving staged pressure reduction and deceleration, effectively controlling the flow velocity and eliminating vibration.
3. Electrical heat tracing is applied to the critical valve components to prevent molten salt solidification, and dedicated bonnet materials with silver-plated metal sealing rings resist structural damage at high temperature.
Customer Value
For the demanding conditions of CSP molten salt systems – high temperature, strong corrosion, large differential pressure, easy crystallization and thermal cycling – this solution prevents molten salt deposition in the valve cavity, suppresses the vibration caused by large differential pressure and withstands 565 °C corrosion and the thermal shock of frequent unit start-ups and shutdowns, helping customers reduce equipment failures, media leakage, unplanned downtime and maintenance costs.
Related Products
Molten Salt Control Valve H200
Molten Salt Butterfly Valve VB200
