Cryogenic adsorption

Catalytic Adsorption. This method can reduce impurities, such as H2, O2, CO, and hydrocarbons, to less than 10 ppb. The catalyst converts these impurities into CO2, H2O, and other species that can then be removed by molecular sieves and cryogenic adsorption. 

Cryogen-free electromagnets, 23 856 Cryogenic adsorption processes, 73 461 Cryogenic air separation, 77 275-278, 752-753... 

Collection. Procedures commonly used to collect vapor-phase organic compounds include whole-air, cryogenic, adsorption, absorption, and de-rivatization methods. Whole-air sampling involves the capture of an air parcel in a container. Stainless steel canisters or plastic bags constructed from an inert material, such as Teflon or Tedlar, are most commonly used. Each of... 

Jain R, Tseng JT. Production of high-purity gases by cryogenic adsorption. AIChE 1997 Annual Meeting, Paper 33b. Los Angeles, 1997. 

The cryogenic adsorption system was specially developed to measure adsorption isotherms of H2 and D2. This system is equipped with a closed helium cycle two-stage Gifford McMahon refrigerator to operate under cryogenic conditions. The adsorption temperature can be kept constant within 0.03 K at 20 K. Adsorption isotherms are obtained by gas adsorption manometry. This method is based on the measurement of the gas pressure in a calibrated, constant volume, at a known temperature. The dead space volume was calculated from a helium calibration measurement at the temperature of interest. Thermal transpiration effect was calibrated according to the work by Takaishi and Sensui [41]. 

In cryogenic adsorption, smaller bed volumes suffice, but the feed must be pretreated to remove condensibles. The fire hazard with charcoal remains and may be worse, because of the possibility of adsorption of ozone produced by radiolysis of oxygen. 

CAVERN cryogenic adsorption vessel enabUng rotor nestling CAW calcium tungstate aluminum sodalite... 

Ismail [41] has reported a detailed analysis of the surface area and morphology of graphite fibers after plasma treatment and high temperature oxidation (HTO). He found that the Active Surface Area (ASA) of the fibers, as measured by O2 absorption, increased from 0.029 m /g to 0.154 vc /g (a 430% increase) with only a 2% bum-off in an O2 plasma. This is essentially the same increase as was found for a HTO of much longer duration. The BET area, as measured using the cryogenic adsorption of Kr, increased only slightly for either treatment. He attributed the apparent differences in area to chemical adsorption of the O2 by active sites left on the surface of the fibers by the plasma treatment. 

It is customary to concentrate the major gaseous fission products (krypton, xenon, and iodine) by cryogenic adsorption. Schell et al. (1997) made the initial efforts to develop an automated portable system for online separation and concentration, with the potential for measuring environmental levels of radioactive gases, including Kr, C, H,... 

Fedorov, A.N., Investigation and improvement of cryogenic adsorption purification of argon from oxygen, Gas Sep. Purif, 9(2), 137-145 (1995). 

Depending on the purity required, hydrogen can be further processed by cryogenic adsorption, solvent absorption, pressure swing adsorption (PSA), cryogenic absorption using liquid nitrogen, membrane separation, and metal hydride adsorption. 

Temperature control - sample Sample prep, from sub-freezing to elevated cryogenic adsorption... 

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