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 .- 18 . (canceled) 
     
     
         19 . A method for preparing a catalyst, comprising:
 mixing 10-65 wt % ZSM-5 zeolite modified by P and one of the metals selected from Fe, Co or Ni, and having an anhydrous chemical expression, calculated by oxide, of (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 M is a metal selected from Fe, Co, or Ni, x is the atom number of M, and Y is a number needed to satisfy the oxidation state of M, 0˜60 wt % clay, and 15˜60 wt % inorganic oxide binder, with 0.5˜15 wt % of one or more transition metal additives selected from the metals of Group VIIIB and 2˜25 wt % P additive; and   spray-drying the obtained mixture;   wherein said components above are calculated by dry basis and the transition metal additive and the P additive are calculated by oxide, and   wherein the contents of the transition metal additive and the P additive do not include the contents of the transition metal and P in the modified ZSM-5 zeolite.   
     
     
         20 . The method according to the  claim 19 , 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 . 
     
     
         21 . The method according to the  claim 19 , in which M is Fe. 
     
     
         22 . The method according to the  claim 19 , in which the metal of Group VIIIB is selected from one or more of Fe, Co and Ni. 
     
     
         23 . The method according to the claim  1 , in which the contents of the modified ZSM-5 zeolite is 20˜50 wt %, the contents of the clay is 10˜45 wt %, the contents of the inorganic oxide binder is 25˜50 wt %, the contents of the transition metal additives selected from the metals of Group VIIIB is 1.0˜10 wt %, and the contents of the P additive is 5˜15 wt %, calculated by dry basis. 
     
     
         24 . The method according to the  claim 23 , in which the metal of Group VIIIB is Fe. 
     
     
         25 . The method according to the  claim 19 , in which the clay is selected from one or mixture of more than one of kaolin, metakaolin, diatomite, sepiolite, attapulgite clay, montmorillonite and rectorite. 
     
     
         26 . The method according to the  claim 19 , 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. 
     
     
         27 . The method according to the  claim 19 , in which the transition metal additive of Group VIIIB is introduced by adding transition metal compounds to the mixture in any step before spray-drying, or introduced after spray-drying through immersion or chemical adsorption of transition metal compounds and calcination. 
     
     
         28 . The method according to the  claim 27 , in which the transition metal compounds are selected from the group consisting of the oxide, hydroxide, chloride, nitrate, sulphate, phosphate and organic compounds of the transition metals. 
     
     
         29 . The method according to the  claim 28 , in which the transition metal compounds are one or more selected from the group consisting of the chloride, nitrate, sulphate and phosphate of the transition metals. 
     
     
         30 . The method according to the  claim 19 , in which the P additive is introduced by adding phosphorous compounds to the mixture before spray-drying. 
     
     
         31 . The method according to the claim  1 , in which the P additive is introduced by phosphorus-alumina sol. 
     
     
         32 . A catalyst, which is prepared by the method of any of the  claims 19 - 31 .