Browsing by Author "Loeffelholz, David"
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Item Carbon Dioxide Removal by Ionic Liquid System (CDRILS): Continuous Operation and Full-Scale Brassboard Testing(50th International Conference on Environmental Systems, 7/12/2021) Henson, Phoebe; Kamire, Rebecca; Yates, Stephen; Skomurski, Sean; Zaki, Rehan; Bonk, Ted; Loeffelholz, DavidThe Carbon Dioxide Removal by Ionic Liquid System (CDRILS) is a light weight, low volume CO2 management technology for air revitalization in commercial and long duration human space missions. CDRILS is based on continuous recirculation of an ionic liquid sorbent between hollow fiber scrubber and stripper contactors. This paper reports further progress in advancing the Technology Readiness Level of the technology. A fully integrated lab-scale CDRILS has been built for an extended durability trial under continuous operation, and in-progress results are reported on its performance. A second CDRILS capable of operating full-scale hollow fiber contactors has also been built, and larger scale integrated scrubber-stripper studies are discussed. Preliminary work has probed the potential for the CDRILS to perform a trace contaminant control function in addition to CO2 and humidity management. Ongoing stability studies on the ionic liquid and membrane contactor components have now reached the 2-year milestone and continue to show little or no degradation of these materials. An updated estimate for system size, weight, and power and prototype design are also presented.Item Scale-up of the Carbon Dioxide Removal by Ionic Liquid Sorbent (CDRILS) System(2019-07-07) Henson, Phoebe; Kamire, Rebecca; Yates, Stephen; Bonk, Ted; Loeffelholz, David; Zaki, Rehan; Fox, Eric; Kaukler, William; Henry, ChristopherThe Carbon Dioxide Removal by Ionic Liquid Sorbent (CDRILS) system is designed for efficient, safe and reliable carbon dioxide (CO2) removal from cabin air on long-duration missions to the Moon, deep space, and Mars. CDRILS integrates an ionic liquid sorbent with hollow fiber membrane contactors for rapid CO2 removal and recovery. The liquid-based system provides continuous CO2 delivery, which avoids complicated valve networks to switch between absorbing and desorbing beds and enables simpler integration to the Sabatier without the need for the CO2 Management System (CMS). Ionic liquids are particularly desirable as liquid absorbents for space applications since they are non-volatile, non-odorous, and have high oxidative stability. The hollow fiber membrane contactors offer both high contact area and rigorous containment between the gas and liquid phases in a microgravity environment. Scale-up of the CDRILS technology has presented a series of fascinating challenges, since the interaction between hollow fiber properties, ionic liquid properties and performance is complex. Properties measured with lab-scale hollow fiber contactors are used to estimate the performance of contactors that are similar in size and form factor to those to be used in flight-scale demonstrations. To accomplish this, component and system models have been built to relate the key scrubber and stripper design and operating variables with performance, and experiments directed to validate the models have been performed. System size, weight and power are all sensitive to component selection, arrangement, operating conditions and scaling. Reliability will be extremely important for any long-range mission and depends critically on the stability of the ionic liquids and of the scrubber and stripper contactors. We will report on our continuing long term stability experiments for the ionic liquid and contactor materials, and our investigation of the physical properties of additional ionic liquids.Item Unit Operation Performance Testing of Cascade Distillation Subsystem(44th International Conference on Environmental Systems, 2014-07-13) Loeffelholz, David; Baginski, Ben; Patel, Vipul; MacKnight, Allen; Schull, Sarah; Sargusingh, Miriam; Callahan, MichaelThe Cascade Distillation System (CDS) is a waste water recovery technology being developed under NASA’s Advanced Exploration System (AES) water recovery project. The Cascade Distiller (CD) is the principal component of the CDS. The CDS prototype unit was extensively tested at NASA Johnson Space Center (JSC) during 2008 and 2009. In 2012 the need for additional CD testing was identified to determine thermodynamic, hydraulic, and distillation performance through experiment at operating conditions of interest. This paper discusses this operational testing performed at Honeywell in 2012 on the prototype Cascade Distiller. The thermodynamic performance demonstrated an average specific energy for recovered water of 92 watt-hr/kg. The limiting process recovery of distilled water was 95% of the feed on a weight basis. The distillation performance was tested using a chemical analysis method that used a water soluble red dye. This new method allows qualitative and quantitative measures of the concentrations of salt in the CD and the distillation efficiency.