Menene Silica Alumina Ratio na Zeolite Molecular Sieve

Menene Matsayin Silica Alumina Na Zeolite Molecular Sieve?

Matsakaicin silica alumina (SiO₂/AlO₃molar rabo) shine mahimmin ma'auni na tsari don ainihin aikin zeolite kwayoyin sieves, yana tasiri kai tsaye da kwanciyar hankali na tsarin su, rarraba rukunin acid, da pore topology. Bari mu koyi game da nau'in -halaye, tsari{2}} alaƙar aiki na sieves kwayoyin halitta na zeolite tare da ma'auni daban-daban na aluminium{3}, da kuma dacewa da aikace-aikacen su a cikin sinadarai na petrochemicals, kare muhalli, da sauransu.

Ma'anar Silica Alumina Ratio

• Matsakaicin silica alumina yana nufin rabon molar ko rabon atomic (Si/Al) na silicon - oxygen tetrahedron (SiO)₄) zuwa aluminum - oxygen tetrahedron (AlO₄) a cikin tsarin sieve kwayoyin halitta. Kuma ƙimar sa yana ƙayyade ƙimar cajin tsarin, da kuma hanyar biyan kuɗi.
• Low silica alumina rabo na kwayoyin sieve yana da babban nauyin caji mara kyau a cikin tsarin, kuma yana buƙatar babban adadin diyya. Tsarin silica alumina rabon siliki na siliki yana mamaye da ƙarfi Si-O-Si bonds, kuma tsarin sa na saman yana da ƙarfi sosai. Silica alumina rabo yana daidaita ƙarfin acid, rarraba girman pore da hydrophobicity na sieve kwayoyin, yana sa ya dace da yanayin masana'antu daban-daban.

Rarraba Na Zeolite Molecular Sieve

Tsarin Tsarin Tsarin Silica Alumina Ratio

• Tsarin acidity: Aluminum atoms sune tushen wuraren Brønsted acid acid, kuma silica alumina rabo kai tsaye yana rinjayar girman acid da ƙarfi: Lokacin da silica alumina rabo ya karu daga 20 zuwa 150, yawan adadin wuraren acid mai rauni (desorption a 120 digiri) da kuma karfi acid shafukan (desorption ragewa) a 400% H 400 digiri. Matsakaicin rukunin wuraren acid mai ƙarfi a cikin babban silica alumina rabo (kamar ZSM-5-300) yana raguwa, yana hana haɓakar canjin hydrogen, kuma zaɓin propylene yana ƙaruwa zuwa 81.5%.
• Tsarin pore da aikin adsorption: Lokacin da silica alumina rabo na ZSM-22 sieve kwayoyin halitta ya karu daga 40 zuwa 130, ƙarar pore ya fara ƙaruwa zuwa 0.25 cm³/g sannan ya ragu zuwa 0.18 cm³/g, because the framework shrinkage is aggravated under high silicon conditions. ZSM-5 molecular sieve with a silica alumina ratio of >100 yana da karfin adsorption na 41 MG / g don toluene, wanda shine 70% mafi girma fiye da na ZSM-5 tare da silica alumina rabo na 38, saboda haɓakar hydrophobicity yana rage haɓakar adsorption na kwayoyin ruwa.
• Kwanciyar zafi da dorewar hydrothermal: Low{0}}silicon Y- nau'in (SiO)₂/Al₂O₃=2) yana fuskantar rugujewar kwarangwal a digiri 660, yayin da babban - siliki ZSM-5 (SiO)₂/Al₂O₃>30) zai iya jure yanayin zafi har zuwa digiri 900. Lokacin da silica alumina rabo a cikin Cu / SSZ-13 mai kara kuzari ya karu daga 6 zuwa 16, yawan riƙewar ayyukan SCR ya karu daga 45% zuwa 85% bayan maganin hydrothermal a digiri 800 / 16h, saboda raguwa a cikin ƙimar ciniki.

Dabarun Adafta Silica Alumina Ratio A cikin Aikace-aikacen Masana'antu

• Fatsawar ruwa mai kaifi (FCC): Lokacin da silica alumina rabon USY kewayon sikelin ƙwayoyin cuta ya kasance 6-8, zaɓin coke yana raguwa da maki 2.5 cikin ɗari kuma yawan man mai haske yana ƙaruwa da kashi 3%.
• Methanol zuwa olefins (MTO): Lokacin da rabon silica alumina na SAPO-34 keɓaɓɓen ƙwayar ƙwayar cuta shine 0.3-0.5, zaɓin ethylene / propylene ya kai 80%. Maɗaukakin silica alumina rabo yana haɓaka jigilar carbon na polycyclic aromatic hydrocarbons kuma yana haifar da kashewa.
• VOCs adsorption: Ƙarfin adsorption na ZSM-5 kwayoyin sieve tare da silica alumina rabo na 300 don jerin benzene shine 120 mg / g, kuma an ƙara lokacin shiga zuwa 66 min, wanda ya fi 40 mg / g na carbon da aka kunna.
• NOx cire: Lokacin da silica alumina rabo na Cu / LTA mai kara kuzari ne 16-23, da NOx hira kudi zauna a 90% bayan hydrothermal tsufa a 600 digiri, wanda yana da duka biyu high aiki da karko.
• Sarrafa miyagun ƙwayoyi saki: Low silica alumina rabo (1.5 ~ 2.0) nau'in A zeolite kwayoyin sieve cimma ci gaba da saki na ibuprofen ta pore size tsari, tare da 24h saki kudi na 95%.
• CO₂kama: Amine{0}} nau'in nau'in nau'in nau'in nau'in zeolite mai aiki (Silica alumina ratio 2.5) yana kula da CO₂karfin adsorption na 12 wt% a ƙarƙashin yanayi mai laushi, kuma juriya na ruwa yana ƙaruwa sau 3.