Session: 07-01: Technoeconomic Analysis of CSP Receivers and Particle Storage Technologies

Paper Number: 132239

132239 - High-Capacity Skip Hoist Design 

Abstract: 

Particle based concentrating solar power (CSP), with research beginning in the 1980s, was determined to be the best candidate for next-generation technology by the Department of Energy (DOE) and funded for a pilot scale demonstration in 2021 due to its promise to increase solar to electric efficiency and decrease price of CSP relative to prior technologies such as nitrate molten salts. Particle CSP systems, notable for higher operating temperatures, utilizes ceramic particles to directly absorb heat from concentrated solar flux and store the heat in large silos before the heat is used to power a high efficiency Brayton power cycle. The particles are extremely abrasive and at high temperatures equipment such as containment material, flow control valves, and ducting can undergo significant degradation.  

Accelerating research into particle based CSP scale has illuminated the need for improved commercial-scale component testing. Sandia National Laboratories (SNL) is currently developing a High Temperature Particle Recirculation LoOP (HoTPROP) to meet this need, a high-flow, electrically heated test facility allowing for lifecycle evaluation of pilot scale valves and test articles. The HotPROP facility will use sintered bauxite particles from CARBO Ceramics Inc, which feature high solar absorbance and stability at high temperatures. Currently, SNL is working with King Saud University (KSU), who has developed a smaller scale recirculation system operating at ~350 °C for pre-testing while the KSU tower is being built, utilizing the same CARBO Ceramic Inc. particles. The KSU setup uses a hoist and skip bin for vertical particle transportation to the top of a gravity fed test loop. It is designed for a skip inventory mass of roughly 120 kg, lifted approximately 10 m by a hoist placed on top of the tower, and overturned via curved guide rails to deposit the particles into the top hopper (which flow through the tower at 1 kg/s) before returning to a lower stow position for recirculation. (After KSU’s tower construction is completed, the components will be raised and integrated within the tower, with the goal of testing up to 600°C.) SNL’s HoTPROP facility will scale this existing system extensively, using a 2240 kg particle payload lifted approximately 19 m for continuous operation up to 500 hours. The HoTPROP facility will feature a high temperature skip hoist capable of maintaining a continuous 25 kg/s mass flow over a test article at 800 °C, and will be designed for minimal heat loss through the insulated skip bin which can withstand temperatures of 900° C.

SNL’s HoTPROP skip hoist will charge and discharge autonomously with counterweight valve systems controlling the inventory levels in a skip charging hopper, or “pre-skip”. Particle flow into the pre skip will be stopped once the desired weight of 2240 kg is reached.  Upon arrival of the skip, the skip lid is lifted for the pre-skip to deposit the particles into the particle lift. A ground-based hoist will raise the skip to the top of the facility where rails will overturn it, emptying the particles into a top hopper.

Further expanding upon KSU’s design, SNL will be considering ways to minimize heat loss during the skips filling, transit, and draining. SNL will also be analyzing the particle’s physical impact on the equipment throughout the testing, i.e., stationary force by the particles on the skip and hoppers, force of impact by the particles on the skip and hoppers while charging/discharging, and, quantifying the severity of abrasion due to the flow of particles at a 25 kg/s flow rate.

Presenting Author: Felicia Brimigion Sandia National Laboratories

Presenting Author Biography: I am a mechanical engineering graduate student working on my third degree. I obtained my first degree in Geology with a minor in physics from Keene State College in 2015. I have always been passionate about being kind to the planet and wanting to assist wherever I can in renewable energies. After taking some time off to figure out how I would achieve that, I decided to return to academics and graduated with a Bachelor of Science in Mechanical Engineering from UNM in 2021. I am currently pursuing my master’s at UNM where I have enjoyed working on UNM’s Solar Splash program with a team that designed and manufactured a solar powered boat to race against other schools' solar powered boats. I have worked as a student intern at Sandia National Laboratories since the summer of 2019, originally in MEMs, and transferred to the Solar Tower working with CSP the summer of 2021. I work with Nathan Schroeder and Randy Brost studying high temperature particle based CSP, and SOFAST mirror optimization, respectively. Outside of engineering, I thoroughly enjoy hiking, reading, movies, crafting, and gaming.

Authors:

Felicia Brimigion Sandia National Laboratories
Dimitri Madden Sandia National Laboratories
Shaker Alaqel King Saud University
Nathan Schroeder Sandia National Labs