Preliminary Investigation of Vortex Phase Separator-Based Spacecraft Cabin Air Dehumidification Subsystem for CO2 Removal

Date

2023-07-16

Journal Title

Journal ISSN

Volume Title

Publisher

2023 International Conference on Environmental Systems

Abstract

Cabin atmosphere revitalization, more specifically CO2 removal, is a key technology to pursue long-duration, crewed space missions. The ISS currently uses the Carbon Dioxide Removal Assembly (CDRA) that employs desiccant (silica gel) and solid sorbent (zeolite) to remove humidity and CO2 from cabin air, respectively. However, CDRA has challenges with high reliability and low maintenance requirements. Air dehumidification is an important process for state-of-the-art and emerging technologies since it helps provide higher CO2 removal efficiency and purer CO2 downstream product. The desiccant in CDRA degrades over time, causes substantial reduction in water removal capacity,?and would require an additional energy cost for regeneration. A promising technology to perform successful dehumidification in support of new CO2 removal systems is the Vortex Phase Separator (VPS). The VPS operation in microgravity relies on creating and maintaining a liquid vortex, which offers centrifugal acceleration in replacement of gravitational acceleration, within a right circular cylinder. Warm and humid air enters the VPS, breaks into very small bubbles, and passes through cold liquid desiccant. Rapid, direct heat and mass exchange between the liquid and gas phases facilitates high water absorption and/or condensation capability, and allows for high throughput per unit energy consumed. This preliminary study investigates the VPS for cabin air dehumidification as part of NASA's spacecraft CO2 removal systems under consideration. A prototype microgravity VPS system was designed, built, and tested to separate water vapor from a warm, humid air stream to characterize its performance using water and ionic liquid (IL) in the separator. Experiments with 77 SCFH airflow rate and 200 ml IL charge demonstrated the VPS capability to reduce up to 45% of water content in a humid air stream.

Description

Chirag Byanjankar, University of North Texas, USA
Alexander Sarvadi, University of North Texas, USA
Huseyin Bostanci, University of North Texas, USA
Cable Kurwitz, Texas A&M University, USA
Grace Belancik, NASA Ames Research Center, USA
ICES302: Physio-chemical Life Support- Air Revitalization Systems -Technology and Process Development
The 52nd International Conference on Environmental Systems was held in Calgary, Canada, on 16 July 2023 through 20 July 2023.

Keywords

Air Revitalization, Carbon Dioxide Removal, Vortex Phase Separator, Liquid Desiccant

Citation