Production of hydrocarbons from pyrolysis of tyres

Abstract

The present invention relates to the development of a process of microwave pyrolysis of end-of-life tyres for the production of high added value pyrolysis oils containing a fraction greater than 40% by weight of distiliable hydrocarbons comprised between 20 and 265° C., and sulphur content less than 1% by weight.

1 . A process comprising subjecting to pyrolysis end-of-life tyres (ELT) by way of irradiation with microwaves (MW), wherein:
 (a) the vapours derived from the pyrolysis reaction are conveyed in a fractionation system before being sent to a condensation system;   or:   (b) the delivery of the MW is adjusted to such a power level as to obtain a mean percentage pyrolysis rate (V M % ) of between 0.30 and 2.00/min and/or a mean heating rate (V M risc ) less than 20° C./min and the vapours derived from the pyrolysis reaction are directly sent to a condensation system, without being conveyed in a fractionation system before being sent to the condensation system;   for obtaining pyrolysis oils having a sulphur content of <1% by weight and said oil having a fraction of hydrocarbons distillable at a temperature comprised between 20 and 265° C., said fraction of hydrocarbons being greater than 40% by weight.   
     
     
         2 . The process according to  claim 1 , subparagraph (a), wherein the fractionation system is selected from:
 Dephlegmator with air-cooling   Dephlegmator with column filled with Fenske, Rashig, Pall, Lessing, and Cross-Partition rings   Dephlegmator with column filled with Berl or Intalox saddles   Dephlegmator with column filled with glass beads of various diameters (0.5 to 4 mm)   Dephlegmator with plate column   or an analogous industrially viable system.   
     
     
         3 . The process according to claim, wherein the delivery of the MW is adjusted to such a power level as to obtain a V M %  greater than 0.4/min and/or a mean heating rate (V M risc ) greater than 5° C./min, for obtaining pyrolysis oils having a sulphur content of <1% by weight and having a fraction of hydrocarbons distillable at a temperature comprised between 20 and 220° C., said fraction of hydrocarbon being greater than 60% by weight. 
     
     
         4 . The process according to  claim 3  wherein the delivery of the MW is adjusted to such a power level as to obtain a V M %  greater than 1.0/min and/or a mean heating rate (V M risc ) greater than 10° C./min. 
     
     
         5 . The process according to  claim 1 , subparagraph (b), wherein the delivery of the MW is adjusted to such a power level as to obtain a mean percentage pyrolysis rate (V M % ) comprised between 0.30 and 1.30/min and/or a mean heating rate (V M risc ) comprised between 5 and 15° C./min, for obtaining pyrolysis oils having a sulphur content of <1% by weight and having a fraction of hydrocarbons distillable at a temperature comprised between 20 and 265° C., said fraction of hydrocarbons being greater than 50% by weight. 
     
     
         6 . The process according to  claim 1 , subparagraph (b), wherein the delivery of the MW is adjusted to such a power level as to obtain a mean percentage pyrolysis rate (V M % ) less than 0.60/min and/or a mean heating rate (V M risc ) less than 6° C./min, for obtaining pyrolysis oils having a sulphur content of <1% by weight and having a fraction of hydrocarbons distillable at a temperature comprised between 20 and 220° C., said fraction of hydrocarbons being greater than 60% by weight. 
     
     
         7 . The process according to  claim 1  wherein the power is delivered in an increasing manner. 
     
     
         8 . The process according to  claim 1  wherein to reduce the sulphur content in the pyrolysis oils, during the process a sulphurated compounds sequestering agent. 
     
     
         9 . The process according to  claim 1  wherein, one or more generators operating at a frequency of 2.45 GHz are used for the delivery of the MW.