Molecular sievesyog cov ntaub ntawv tseem ceeb siv nyob rau hauv ntau yam kev lag luam rau kev sib cais molecules raws li lawv qhov loj thiab cov duab. Lawv yog crystalline hlau aluminosilicates nrog peb-dimensional interconnecting network ntawm alumina thiab silica tetrahedra. Feem ntau sivmolecular sievesyog 3A thiab 4A, uas txawv ntawm lawv qhov pore qhov ntau thiab tsawg thiab kev siv.
4A molecular sieves muaj qhov pore loj ntawm kwv yees li 4 angstroms, thaum3A molecular sievesmuaj qhov pore me me ntawm ib ncig ntawm 3 angstroms. Qhov sib txawv ntawm qhov pore loj ua rau muaj kev hloov pauv hauv lawv lub peev xwm adsorption thiab kev xaiv rau cov molecules sib txawv.4A molecular sievesfeem ntau yog siv rau lub cev qhuav dej ntawm cov pa roj thiab cov kua dej, nrog rau kev tshem tawm cov dej los ntawm cov kuab tshuaj thiab cov nkev ntuj. Ntawm qhov tod tes, 3A molecular sieves feem ntau yog ua haujlwm rau lub cev qhuav dej ntawm unsaturated hydrocarbons thiab polar compounds.
Qhov sib txawv ntawm qhov pore loj kuj cuam tshuam rau hom molecules uas tuaj yeem adsorbed los ntawm txhua hom molecular sieve. 4A molecular sieves zoo nyob rau hauv adsorbing loj molecules xws li dej, carbon dioxide, thiab unsaturated hydrocarbons, thaum 3A molecular sieves yog ntau xaiv rau me me molecules xws li dej, ammonia, thiab cawv. Qhov kev xaiv no yog qhov tseem ceeb hauv cov ntawv thov uas tshwj xeeb impurities yuav tsum tau muab tshem tawm los ntawm kev sib xyaw ntawm cov roj av lossis cov kua dej.
Lwm qhov tseem ceeb uas yuav tsum tau xav txog thaum xaiv ntawm3A thiab 4A molecular sievesyog lawv muaj peev xwm tiv taus ntau theem ntawm cov av noo. 3A molecular sieves muaj kev tiv thaiv ntau dua rau cov dej vapor piv rau 4A molecular sieves, ua rau lawv tsim nyog rau cov ntawv thov uas muaj kev txhawj xeeb. Qhov no ua rau 3A molecular sieves zoo tagnrho rau kev siv hauv huab cua thiab roj kom qhuav cov txheej txheem uas tshem tawm cov dej yog qhov tseem ceeb.
Nyob rau hauv cov nqe lus ntawm kev lag luam, 4A molecular sieves yog feem ntau siv nyob rau hauv zus tau tej cov oxygen thiab nitrogen los ntawm huab cua sib cais txheej txheem, raws li zoo raws li nyob rau hauv qhuav ntawm refrigerants thiab natural gas. Lawv lub peev xwm los tshem tawm dej thiab carbon dioxide zoo ua rau lawv muaj txiaj ntsig hauv cov txheej txheem no. Ntawm qhov tod tes, 3A molecular sieves pom kev siv dav hauv kev ziab ntawm unsaturated hydrocarbons, xws li cov pa tawg, propylene, thiab butadiene, nrog rau kev ua kom huv ntawm cov kua roj av.
Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias kev xaiv ntawm 3A thiab 4A molecular sieves nyob ntawm cov kev cai tshwj xeeb ntawm daim ntawv thov, suav nrog hom molecules yuav tsum tau adsorbed, qib ntawm cov av noo tam sim no, thiab qhov xav tau purity ntawm cov khoom kawg. Kev nkag siab qhov sib txawv ntawm cov molecular sieves yog qhov tseem ceeb rau kev xaiv cov kev xaiv tsim nyog tshaj plaws rau ib qho kev lag luam.
Hauv kev xaus, thaum ob leeg3A thiab 4A molecular sievesNws yog ib qho tseem ceeb rau ntau lub cev qhuav dej thiab kev ua kom huv si, lawv qhov sib txawv ntawm qhov pore loj, adsorption selectivity, thiab tiv thaiv cov av noo ua rau lawv haum rau cov kev siv sib txawv. Los ntawm kev nkag siab txog qhov sib txawv no, kev lag luam tuaj yeem txiav txim siab paub txog kev xaiv thiab siv cov molecular sieves los txhim kho lawv cov txheej txheem thiab ua tiav cov khoom xav tau purity.
Post lub sij hawm: Jun-27-2024