Design, construction and testing of a pumped molten chloride circulation loop

Abstract

Next generation concentrating solar power (CSP) with thermal energy storage is envisioned to operate with a peak temperature of 700 °C or higher, but transitioning from a stainless steel to a nickel alloy infrastructure is prohibitively expensive. In light of this challenge, the present work investigates the use of refractory materials instead of nickel alloys. This thesis presents the design, construction and testing of a laboratory-scale pumped circulation loop made of refractory materials to circulate molten chloride salt above 700 °C. The components of the loop were initially constructed from conventional refractory materials such as graphite, carbon-carbon composite, molybdenum, and alumina, though the loop was subsequently adapted to test a laboratory-scale tank and pipe made of a novel calcium hexaluminate-based castable refractory designed to resist corrosion and penetration by molten chloride salt. In addition, this thesis describes the design and operation of a convection-enhanced rotating disk corrosion test apparatus to study the corrosion behavior of refractory materials in molten chloride salt under flowing conditions.