Catalyst and a Method for Cracking Hydrocarbons

Abstract

The invention discloses a catalyst and a method for cracking hydrocarbons. The catalyst comprises, calculated by dry basis, 10˜65 wt % ZSM-5 zeolite, 0˜60 wt % clay, 15˜60 wt % inorganic oxide binder, 0.5˜15 wt % one or more metal additives selected from the metals of Group VIIIB and 2˜25 wt % P additive, in which the metal additive is calculated by metal oxide and the P additive is calculated by P 2 O 5 . The method for cracking hydrocarbons using this catalyst increases the yield of FCC liquefied petroleum gas (LPG) and the octane number of FCC gasoline, as well as it increases the concentration of propylene in LPG dramatically.

1 . A catalyst, which comprises, calculated by dry basis, 10˜65 wt % ZSM-5 zeolite, 0˜60 wt % clay, 15˜60 wt % inorganic oxide binder, 0.5˜15 wt % one or more metal additives selected from the metals of Group VIIIB and 2˜25 wt % P additive in which the metal additive and the P additive are calculated by oxide. 
   
   
       2 . A catalyst according to  claim 1  in which the catalyst is consisted of, calculated by dry basis, 20˜50 wt % ZSM-5 zeolite, 10˜45 wt % clay, 25˜50 wt % inorganic oxide binder, 1.0˜10 wt % one or more metal additives selected from the metals of Group VIIIB and 5˜15 wt % P additive. 
   
   
       3 . A catalyst according to  claim 1  in which the ZSM-5 zeolite is modified by P and one of the metals selected from Fe, Co or Ni, the anhydrous chemical expression, calculated by oxide, is (0˜0.3) Na 2 O.(0.5˜5)Al 2 O 3 .(1.3˜10)P 2 O 5 .(0.7˜15)M x O y .(70˜97)SiO 2 , in which x is the atom number of M and Y is a number needed to satisfy the oxidation state of M. 
   
   
       4 . A catalyst according to  claim 3  in which the anhydrous chemical expression of ZSM-5 zeolite, calculated by oxide, is (0˜0.2) Na 2 O.(0.9˜3.5)Al 2 O 3 .(1.5˜7)P 2 O 5 .(0.9˜10)M x O y .(82˜92)SiO 2 . 
   
   
       5 . A catalyst according to  claim 3  in which M is Fe. 
   
   
       6 . A catalyst according to  claim 1  or  2  in which the metal of Group VIIIB is selected from one or more of Fe, Co and Ni. 
   
   
       7 . A catalyst according to  claim 6  in which the metal of Group VIIIB is Fe. 
   
   
       8 . A catalyst according to  claim 7  in which the XRD patterns comprise at least the characteristic diffraction peaks of FePO species at 2θ=16.35±0.5°, 26=26.12±0.5° and 2θ=30.94±0.5°. 
   
   
       9 . A catalyst according to  claim 1  in which the clay is selected from one or mixture of more than one of kaolin, metakaolin, diatomite, sepiolite, attapulgite clay, montmorillonite and rectorite. 
   
   
       10 . A catalyst according to  claim 1  in which the inorganic oxide binder is selected from one or mixture of more than one of pseudoboehmite, alumina sol, silica-alumina sol, water glass and  phosphorus-alumina sol. 
   
   
       11 . A catalyst according to  claim 1  in which the inorganic oxide binder is selected from one or mixture of more than one of pseudoboehmite, alumina sol and phosphorus-alumina sol. 
   
   
       12 . A method for cracking hydrocarbons in which the hydrocarbons are contacted with a catalyst mixture containing the catalysts disclosed in one of  claims 1 - 11  under the cracking condition, and then the cracked products are collected. 
   
   
       13 . A method according to  claim 12  in which the contact procedure of hydrocarbons and the catalyst mixture containing the catalysts disclosed in one of  claims 1 - 11  is proceeded on a fixed-bed reactor, a fluidized-bed reactor or a moving-bed reactor, the reaction temperature is 400˜650° C., the catalyst-to-oil weight ratio is 1˜25 and the weight hourly space velocity is 10˜120 h −1 . 
   
   
       14 . A method according to  claim 13  in which the reaction temperature is 420˜600° C., the catalyst-to-oil weight ratio is 3˜20 and the weight hourly space velocity is 15˜80 h −1 . 
   
   
       15 . A method according to  claim 12  in which the contact procedure of hydrocarbons and the catalyst mixture containing the catalysts disclosed in one of  claims 1 - 11  is proceeded on a riser reactor, the cracking condition including a reaction temperature of 400˜650° C., a catalyst-to-oil weight ratio of 1˜25 and a reaction time of 0.5˜15 s. 
   
   
       16 . A method according to  claim 15  in which the reaction temperature is 420˜600° C., the catalyst-to-oil weight ratio is 3˜20 and the reaction time is 0.5˜10 s. 
   
   
       17 . A method according to  claim 12  in which the content of the catalysts disclosed in one of  claims 1 - 11  in the catalyst mixture is 1˜30 wt %. 
   
   
       18 . A method according to  claim 17  in which the content of the catalysis disclosed in one of  claims 1 - 11  is 3˜20 wt %.