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Removing N2O with 13X Molecular Sieve by Temperature Swing Adsorption (TSA) Disclosure Number: IPCOM000021490D
Publication Date: 2004-Jan-21
Document File: 2 page(s) / 35K

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Removing N2O with 13X Molecular Sieve by Temperature Swing Adsorption (TSA)




The present invention is a method for sizing temperature swing adsorption beds for removal of N2O from an air stream. This is achieved by including additional 13X in the bed that will be used to remove N2O.


When an air stream is used for cryogenic separation, H2O and CO2 must be removed for safe and reliable operation of the cryogenic equipment. Both of these contaminants will form solids that plug operating equipment. To remove the H2O and CO2, a pre-purification unit (PPU) is used. One type of PPU is a Temperature Swing Adsorption (TSA) system.

A TSA typically consists of two vessels. One vessel is on-line operating on air. The other vessel is being regenerated with clean waste gas. The air leaving the online bed is free of H2O and all but a trace quantity of CO2. Normally, the amount of 13X in the TSA is sized so that only a trace amount of CO2 will break through at the end of the on-line time. In this way, approximately one third to two thirds of the ambient N2O will break through the TSA. The reason is that the selectivity of the 13X for N2O versus CO2 is low. As the 13X adsorbs CO2, the N2O is displaced from the 13X.

A typical breakthrough curve for N2O and CO2 is shown in Figure 1.


From the breakthrough curve, notice that the N2O breaks through long before CO2. For some types of equipment, having an N2O breakthrough as shown can be a problem. N2O can solidify and trap hy...