chế tạo xúc tác fcc
TRANSCRIPT
Ch to xc tc FCC C rt nhiu phng php ch to cht xc tc FCC c cng b trong rt nhiu bng sng ch pht minh. Sau y, mt s phng php thng hay c cc nh sn xut xc tc s dng nht. 1. Phn loi cc phng php sn xut cht xc tc FCC Cht xc tc FCC c th c sn xut theo hai phng php chnh: a) Cc zeolit c tng hp trc, sau mi phi trn vo cht nn. b) Zeolit c hnh thnh (kt tinh) trong pha nn khong st t nhin. Phng php th nht hu nh c tt c cc nh sn xut cht xc tc FCC s dng. Vi phng php ny c hai iu kin khc bit: - Zeolit c trao i ion vi cc cation cn thit, sau mi phi trn vo cht nn (I). - Zeolit c trao i ion sau khi phi trn vi pha nn (II). Sn xut cht xc tc FCC theo cch (I) thng gm cc bc: (a) tng hp, trao i ion v bin tnh cu trc zeolit, (b) phi trn zeolit vi pha nn v (c) sy phun hn hp xc tc (zeolit + pha nn); theo cch (II), zeolit sau khi tng hp c trn vo pha nn v sy phun, tip n tin hnh trao i ion. 2. Ch to cc zeolit 2.1. Zeolit Y Hnh 3.12 gii thiu mt s kt tinh, trao i ion v bin tnh cu trc ca zeolit Y. Zeolit Y thng c iu ch dng NaY t ngun silic (ch yu l silica natri), ngun nhm (aluminat natri) v hydroxyt natri. Mt s cht mm khi mo cho qu trnh kt tinh NaY cng c thm vo hn hp gel tng hp zeolit. S kt tinh thng c tin hnh trong mt thit b kt tinh ln, ko di t 8 gi cho n vi ngy, ty thuc vo ngun nghin liu ban u, iu kin kt tinh, tinh th ca zeolit v thnh phn ha hc ca zeolit sn phm Zeolit sau khi kt tinh
Zeolit Y thng c iu ch dng NaY t ngun silic (ch yu l silicat natri), ngun nhm (aluminat natri) v hydroxyt natri. Mt s cht mm khi mo cho qu trnh kt tinh NaY cng c thm vo hn hp gel tng hp zeolit. S kt tinh thng c tin hnh trong mt thit b kt tinh ln, ko di t 8 gi cho n vi ngy, ty thuc vo ngun liu ban u, iu kin kt tinh, tinh th ca zeolit v thnh phn ha hc ca zeolit sn phm. Zeolit sau khi kt tinh c tc ra khi pha lng bng cc my lc ly tm v ra bng nc. NaY c cht lng tt phi c t s SiO2/Al2O2 5, b mt ring khong 800m2/g, tinh th cao (so vi zeolit chun). Tp cht khng ng k (pht hin bng XRD), kch thc ht c 1 5 m. 2.2. Trao i ion NaY sau khi tng hp c trao i ion vi cc cation t him (RE) hoc/v vi NH4+ chuyn zeolit NaY v dng hot ng v bn thy nhit. S trao i ion