Carbon dioxide concentration for manned spacecraft using a molten carbonate electrochemical cell

Abstract

A high-temperature molten carbonate electrochemical cell has been tested for

Lithium silicate based membranes for high temperature CO2 separation

“…Although the present level of membrane separation technology is immature compared with the other processes, the membrane separation process is considered to be one of the least energy-demanding processes if membranes that could withstand the process temperature and conditions are available. Although membrane separation of CO 2 is reported widely [4,5], apart from molten salt based CO 2 concentrators as reported by Winnick et al in 1982 [6], membranes that could withstand high temperatures in the order of 500-600 o C are rarely reported. Furthermore, membranes such as microporous silica membranes, even if they could be processed with high CO 2 separation factors at high temperature, will definitely allow higher permeance of lighter molecules such as hydrogen making selective separation of CO 2 practically impossible from (for e.g.)…”

Faradaic electro-swing reactive adsorption for CO2 capture

“…10 The first of such systems was developed by Winnick et al, for the electrochemical capture of CO 2 in spacecraft cabins using molten carbonates. 11 However, the low concentration of CO 2 in such applications poses a challenge, mainly due to the low driving forces for mass transfer and the large quantities of other species present in air in addition to CO 2 . 12 Thus, carbon capture is a multi-scale problem, where the CO 2 -rich streams to be treated vary greatly in volume, concentration and composition, and different criteria need to be fulfilled to ensure optimal processing depending on whether sources are industrial or small-scale (e.g., power plants or oil and gas heaters), concentrated or dilute (exhausts from combustion or air in confined spaces), and clean or contaminated with other pollutants.…”

Carbonate Dynamics and Opportunities With Low Temperature, Anion Exchange Membrane-Based Electrochemical Carbon Dioxide Separators

“…Electrochemical processes are promising alternatives for the separation, concentration, and compression of CO2 since they are not bound by thermochemical cycles and so their theoretical energy requirements will always be lower [15][16][17] [REFS. High temperature electrochemical cells based on ceramic and molten carbonate electrolytes have been considered [18][19][20][21], but these systems require high heat input and suffer dynamic (operation) instabilities in addition to the electrical cost, making low temperature systems more suitable for large-scale CO2 separation. One low temperature electrochemical approach that has been recently explored is the sorption of CO2 by electrochemically reduced disulfides (thiolates) in tetraalkyl phosphonium/ammonium ionic liquid (IL) leading to the formation of thiocarbonates.…”