Circulated Molten Salt Systems

Circulated molten salt systems are used to distribute hot liquid salt as a heat medium to heat exchangers or other process heat consumers.

Function & Design

Once the energy is needed, the molten salt circulation process begins. Most systems maintain the salt above its freezing point to avoid the process of remelting, but during commissioning or a cold restart situation the salt is melted in a hot salt tank. The molten salt is then circulated through a closed loop system using a circulation pump specifically designed for pumping hot salt.  Fluid circulates from the hot salt tank to a fired heater or electric heater, out to the user, and then back again to the hot salt tank.

The system is generally designed in such a way that hot salt will return to the hot salt tank if and when the circulation pumps are turned off. It is unique from other closed loop heating systems because of the freezing point of the salt.  The system has to be designed using a hot salt tank, to which the fluid always returns when the system is down.

These systems should be heated and designed to prevent freezing or thermal shock in the circulation piping. Molten salt is stored in these systems at temperatures of 1050°F at normal atmospheric pressure. In these systems, sensors are applied to measure and monitor liquid levels, pressures, temperatures, and flow rates.

Circulated molten salt systems can provide plants with an integrated energy storage option designed to meet specific application needs. This energy storage concept is commonly used in solar power plants to store heat energy for power production at night time or overcast periods.

Sigma Thermal offers circulated molten salt systems for your energy needs in our products including HC1, HC2, convection heater, and electric heaters. Should you have any questions about molten salt systems, contact Sigma Thermal.