摘要:
An improved method for preparing various sorbent shapes such as beads for use in gas separation processes is disclosed. Highly siliceous nanoporous materials in their crystalline powder form are stabilized by thermal pretreatment prior to their contact with a mineral binder. The resulting sorbent shapes maintain their crystalline structure particularly when the pH value of the mineral binder in its aqueous suspension is greater than 10. The sorbent beads that result from this process, are especially suitable for the separation of gaseous low-molecular-weight hydrocarbons such as paraffins, olefins, and their mixtures from carbon dioxide in wet atmospheres.
摘要:
An improved method for preparing various sorbent shapes such as beads for use in gas separation processes is disclosed. Highly siliceous nanoporous materials in their crystalline powder form are stabilized by thermal pretreatment prior to their contact with a mineral binder. The resulting sorbent shapes maintain their crystalline structure particularly when the pH value of the mineral binder in its aqueous suspension is greater than 10. The sorbent beads that result from this process, are especially suitable for the separation of gaseous low-molecular-weight hydrocarbons such as paraffins, olefins, and their mixtures from carbon dioxide in wet atmospheres.
摘要:
A composite zeolite product is prepared by crystallizing a sodium ion- or sodium ion- and potassium ion-containing alumina-silica hydrogel under conditions which result in the production of a zeolitic composite which contains both zeolite type A and zeolite type X crystal domains. The composite is ion exchanged with divalent cations. In a preferred embodiment, calcium ions constitute a substantial number of the composite's exchangeable cations and the type X portion of the composite zeolite product has a silicon-to-aluminum atomic ratio in the range of 0.9 to less than 1.15. The composite is a nitrogen oxide- and hydrocarbon-selective adsorbent which can be incorporated into an atmospheric air prepurification plant downstream of a water vapor-selective adsorbent and a carbon dioxide-selective adsorbent.
摘要:
Zeolites exchanged with lithium, caesium or rubidium cations and polyvalent cations (e.g. pure earths or Group III cation) are prepared by first partially ion-exchanging a sodium-containing zeolite, a potassium-containing zeolite or a sodium- and potassium-containing zeolite with polyvalent cations, then heat-treating the partially polyvalent cation-exchanged zeolite, then ion exchanging the heat-treated zeolite with ammonium cations, and then reacting the ammonium cation-exchanged zeolite with a water-soluble lithium compound under conditions which result in the removal of ammonia from the reaction zone.