Corrosion in Molten Salts for Solar Thermal Power

Abstract

Global energy needs continue to grow steadily with increasing population and standard of living. While fossil fuels have been a major source of our energy, they are no longer favorable due to their greenhouse gas emissions and atmospheric pollution; the development of carbon-free sources of energy is crucial. Solar energy promises unlimited amounts of emissions-free energy but suffers from intermittency issues that require expensive secondary energy storage systems to act as baseload power. A thermal energy storage (TES) system can store heat and provide a continuous source of power. Concentrated solar power (CSP) is carbon-free and can ideally be combined with a TES system to provide continuous power. These combined systems operate by focusing a large area of sunlight onto a receiver that contains a TES material to convert the sunlight into thermal energy.

Solar Salt above 600 °C: Impact of Experimental Design on Thermodynamic Stability Results

“…Consequently, oxide ion formation can thermodynamically never reach equilibrium and should continue to increase during the lifetime of the plant to an unacceptable level. This can potentially result in aggravated corrosion, which is a crucial factor hindering TES with nitrate salts by moving to higher operating temperatures [22][23][24].…”

Demonstration of the stabilization of solar salt at 620 C with a semi-closed configuration in a 100 kg-scale

“…O 2− , O 2 − , - ) takes places, as can be seen in reaction (2). Despite the fact that reaction (2) is widely accepted, the exact stoichiometry has not been verified yet and other reaction paths might be favored at different temperatures and gas compositions [ 12 , 17 , 18 ]. in recent years, experiments in a laboratory scale (≤150 g) showed the possibility of stabilizing molten Solar Salt at elevated temperatures up to 620 °C either by purging the gas atmosphere with reactive gases (NO x and O 2 ) or by closing the system and conserving the evolving gases under pressure build-up inside the system [ 19 , 20 ].…”

Optical Basicity for Understanding the Lewis Basicity of Chloride Molten Salt Mixtures

“…Molten halide salts are a valuable media for heat transfer and storage in concentrating solar power (CSP) energy conversion, nuclear power reactors, and for thermal energy storage (TES) . Due to their ability to operate at high temperatures, these salts can facilitate increases in thermodynamic energy conversion efficiency and enable the production of alternative products like hydrogen and industrial chemicals.…”