Olefin and aromatics production by the catalytic pyrolysis of polymers

Abstract

The invention comprises methods of catalytically pyrolyzing plastics. Since it has been discovered that plastics provide insufficient coke to provide adequate heat during catalyst regeneration, heat-forming additives can be introduced into the methods. Systems and compositions useful in the catalytic pyrolysis of plastics are also described.

1 - 66 . (canceled) 
     
     
         67 . A process for converting plastics to olefinic monomers comprising:
 heating a plastic feed to a pyrolysis temperature of at least 400° C. to pyrolyze the plastic feed;   contacting with catalyst to produce a catalytic product stream comprising at least about 50 wt % of olefinic monomers;   separating the catalytic product stream from a bulk of the catalyst; and   quenching the catalytic product stream.   
     
     
         68 . The process of  claim 67  further comprising contacting the vaporous pyrolysate stream with catalyst at a temperature of at least 500° C. 
     
     
         69 . The process of  claim 67  further comprising continuously feeding said plastic feed to a pyrolysis zone in which the heating step occurs. 
     
     
         70 . The process of  claim 69  further comprising passing said vaporous pyrolysate stream to a catalytic zone in which said contacting step occurs. 
     
     
         71 . The process of  claim 70  wherein said catalytic zone is a moving bed or a fixed bed of catalyst. 
     
     
         72 . The process of  claim 71  further comprising carrying said vaporous pyrolysate stream in a diluent gas from a pyrolysis zone to said catalytic zone and contacting said vaporous pyrolysate stream in said diluent gas with said catalyst. 
     
     
         73 . The process of  claim 67  further comprising fluidizing said catalyst with a diluent gas; contacting said catalyst with said plastic feed at pyrolysis temperature to produce said vaporous pyrolysate stream; and contacting said vaporous pyrolysate stream with said catalyst at catalytic pyrolysis temperature to provide said catalytic product stream. 
     
     
         74 . The process of  claim 73  further comprising separating the catalytic product stream from a bulk of said catalyst and quenching said catalytic product stream. 
     
     
         75 . The process of  claim 67  further comprising quenching said catalytic product stream to below 450° C. 
     
     
         76 . A process for converting plastics to olefinic monomers comprising:
 heating a plastic feed to pyrolyze the plastic feed to provide a vaporous pyrolysate contacting the vaporous plastic pyrolysate stream with a catalyst having a silica-to-alumina ratio of at least 20 at a temperature of about 500 to about 700° C. to produce a catalytic product stream comprising at least about 50 wt % of olefinic monomers;   separating the catalytic product stream from a bulk of the catalyst;   quenching the catalytic product stream to below 500° C. within 5 seconds after said separation by heat exchange with water.   
     
     
         77 . The process of  claim 67  wherein the quenching step comprises quenching to below 500° C. 
     
     
         78 . The process of  claim 77  wherein the quenching step comprises quenching with a liquid organic product of the process. 
     
     
         79 . The process of  claim 77  wherein the catalytic process stream is quenched within 5 seconds after said separation. 
     
     
         80 . The process of  claim 67  wherein the catalyst comprises ZSM-5. 
     
     
         81 . The process of  claim 67  wherein the catalyst comprises ZSM-11 having a SiO 2 /Al 2 O 3  molar ratio of 50. 
     
     
         82 . The process of  claim 67  wherein the olefin monomers comprise ethylene and propylene. 
     
     
         83 . The process of  claim 67  wherein the catalytic process stream comprises 50 to 70 wt % of C 2 -C 4  alkenes. 
     
     
         84 . The process of  claim 67  having a residence time of 8 seconds or less. 
     
     
         85 . The process of  claim 67  wherein the step of quenching is conducted to a temperature between the boiling point of the olefinic monomers and the boiling point of toluene. 
     
     
         86 . The process of  claim 67  wherein the step of quenching comprises quenching with water. 
     
     
         87 . The process of  claim 67  further comprising a downstream conversion of the olefinic monomers. 
     
     
         88 . The process of  claim 87  co-located with a steam cracking facility.