(128a) High Operating Temperature Transfer and Storage (HOTTS) System for Concentrated Solar Power Generation and Industrial Heat Integration

Authors: 
Bonino, C., RTI International
Cook, B., RTI International
Hlebak, J., RTI International
Baldasaro, N., RTI International
Gould, R., North Carolina State University

Heat transfer and storage technologies for industrial processes, such as concentrated solar power and metals production, are limited by the high temperature stability of their constituent materials. We are developing a High Operating Temperature Transfer and Storage (HOTTS) process, which will enable high quality heat integration at temperatures up to and exceeding 1,100°C. The HOTTS process integrates two key technologies: a high-temperature, material of construction (MOC) and a novel particle-based heat transfer fluid (pHTF). The MOC is composed of Mo-Si-B composites, which exhibit excellent oxidative and erosive resistance. The pHTF flows freely, can be conveyed by air, and resists sintering in overnight storage conditions.

In this study, we report on approaches to apply the MOC as a protective coating for molybdenum substrates, including a solution-based technique. We compare the coating coverage, morphology, and substrate adhesion to the oxidative stability of the composite at temperatures above 1,100°C in air. This composite material offers the potential to combine the excellent high temperature mechanical properties of Mo (e.g., creep strength) with the oxidative protection of Mo-Si-B. We also discuss the development of a pilot-scale system for evaluating the heat transfer performance of the pHTF. Heat-transfer coefficients are determined for mass fluxes above 100 kg/m2-s in moving- and fluidized-bed-type configurations. Engineering approaches to integrate the MOC into the HOTTS process, as well as heat integration strategies into industrial processes will also be discussed.