Adsorbent Modification And Process Simulation In Oxygen Adsorption Enrichment

In this thesis, the preliminary study is carried out for the development of enriched-oxygen process using waste heat,first, the effects on enriched-oxygen of commercial molecular sieves in different oxygen enrichment processes are considered and main factors affecting the process are invistigated; Secondly, the ion exchange approaches are explored for developing new enriched-oxygen zeolite molecular sieve (ZMS). In the ion exchange experiments , the approaches of calcium (or strontium or lithium) ion direct exchange,(potassium/ alkali )-ammonium-Lithium method and (alkali)-calcium-lithium channels are adopted to modify the raw material( 5A-2, 13X-1, self-LSX zeolite). The modified ZMS are characterized by measuring N2 adsorption capacity, ion exchange degree, XRD etc.; Finally, a single bed and two-bed vacuum PSA oxygen enrichment are simulated using ASPEN ADSIM software to predict separation performance of the synthesized adsorbent.A good adsorption performance adsorbent and a matching process are essential for an oxygen enrichment process. The enriched-oxygen ZMS of UOP and Shanghai Chemical Industry Institute are evaluated with two-bed or three-bed processes. In the experiment, regeneration method, adsorption and pressure equalizing time are considered as important operation parameters. The current commercial molecular sieves are of large specific heat and low separation performance, unsuitable for PSA oxygen enrichment process using waste heat.In the calcium - lithium modified ZMS, it is concluded that the exchange time is few, the adsorption capacity is greatly improved, (at 25oC, 0.1MPa, nitrogen adsorption capacity of CaX3-100 is 0.89mmol / g, Li-X7′is 0.78mmol / g). For (potassium) - ammonium– lithium method, the amount of used lithium is less and more than 90% of the exchange degree can be achieved for one lithium-step reaction.By ASPEN ADSIM, breakthrough and two-bed enriched-oxygen process are simulated, for synthesized CaX3-100, the oxygen concentration of two-bed enriched-oxygen process simulation reached 91.5%, and the recovery rate is 44.3%.