System for the production of synthetic fuels

Abstract

A system and method for producing synthetic fuels are disclosed in which a slurry comprised of a particulate solid portion and a carrier liquid portion is provided. The solid portion comprises (i) a feedstock of carbon-containing polymeric materials that are substantially free of each of halogen, sulfur and nitrogen atoms, and contain about 5 to about 25 percent by weight water, and (ii) a catalytic amount of metal particles. The carrier liquid portion is a hydrocarbon/oxyhydrocarbon composition. The feedstock constitutes about 10 to about 60 weight percent of the slurry. The slurry is heated anaerobically to provide an elevated temperature of about 250° to about 455° C. and a pressure of about 20 to about 50 atmospheres that are maintained for a time period sufficient to provide a combustible liquid fuel at least 80 percent of which contains about 6 to about 21 carbon atoms per molecule.

1 . A method of producing a combustible liquid fuel that comprises the steps of:
 a) providing a slurry comprised of a particulate solid portion and a carrier liquid portion, said solid portion comprising (i) a feedstock of carbon-containing polymeric materials that are substantially free of each of halogen, sulfur and nitrogen atoms, said feedstock containing about 5 to about 25 percent by weight water, (ii) a catalytic amount of Group VIII, IB, IIB, IIIA, or IVA metal particles comminuted to pass through a No. 18 Standard Sieve, and (iii) a carrier liquid portion that is a hydrocarbon/oxyhydrocarbon composition, wherein the feedstock constitutes about 10 to about 60 weight percent of said slurry and said hydrocarbon/oxyhydrocarbon composition having the viscosity and boiling characteristics of gasoline to lubricating oil;   b) heating the slurry anaerobically to provide an elevated temperature of about 250° to about 455° C. and a pressure of about 20 to about 50 atmospheres;   c) maintaining said elevated temperature and pressure for a time period sufficient to provide a combustible liquid fuel at least 80 percent of which contains about 6 to about 21 carbon atoms per molecule, whereby maintenance at higher temperature and pressure for a constant time period lead to a product containing fewer carbon atoms per molecule as does maintenance at a constant temperature and pressure with a longer period of time.   
     
     
         2 . The method according to  claim 1 , wherein the particulate feedstock carbon-containing polymeric materials are comprised of biomass including one or both of a cellulosic material and lignin. 
     
     
         3 . The method according to  claim 1 , wherein the one or both of a cellulosic material and lignin are provided by a source selected from the group consisting of wood chips, sawdust, brush, hay, straw, switch grass, corn stalks, kudzu, paper and cardboard, and mixtures thereof 
     
     
         4 . The method according to  claim 1 , wherein the particulate feedstock carbon-containing polymeric materials are comprised of a synthetic polymer. 
     
     
         5 . The method according to  claim 4 , wherein the synthetic polymer is a rubber. 
     
     
         6 . The method according to  claim 5 , wherein the comminuted metal particles and the rubber synthetic polymer are provided by comminuted tires. 
     
     
         7 . The method according to  claim 6 , wherein 80% or more of the comminuted tires have a largest dimension of less than about 500 microns. 
     
     
         8 . The method according to  claim 6 , wherein the particulate feedstock pieces comprise shredded tire particles, 80% or more of which have a largest dimension of less than about 300 microns. 
     
     
         9 . The method according to  claim 1 , wherein at least 80 percent of said combustible liquid fuel is comprised of molecules that contain about 6 to about 12 carbon atoms per molecule. 
     
     
         10 . The method according to  claim 1 , wherein at least 80 percent of said combustible liquid fuel is comprised of molecules that contain about 12 to about 21 carbon atoms per molecule. 
     
     
         11 . The method according to  claim 1 , wherein at least 80 percent of said combustible liquid fuel is comprised of molecules that contain about 15 to about 19 carbon atoms per molecule. 
     
     
         12 . The method according to  claim 1 , wherein the particulate feedstock carbon-containing polymeric materials are comprised of biomass including one or both of a cellulosic material and lignin in combination with ground tire particles. 
     
     
         13 . The method according to  claim 1 , wherein the catalytic metal particles are comprised of one or more Group VIII metals. 
     
     
         14 . The method according to  claim 13 , wherein the catalytic metal particles are comprised of iron. 
     
     
         15 . The method according to  claim 1 , wherein at least about 80% of the catalytic metal particles are sized to pass through a No. 35 Standard Sieve. 
     
     
         16 . The method according to  claim 1 , wherein at least about 80% of the catalytic metal particles are sized to pass through a No. 50 Standard Sieve. 
     
     
         17 . The method according to  claim 1 , wherein a portion of the combustible fuel produced is recycled to provide part of the carrier liquid portion of the slurry. 
     
     
         18 . The method according to  claim 1 , wherein the metal particles are present at about 1 to about 10 weight percent of the feedstock. 
     
     
         19 . The method according to  claim 18 , wherein the metal particles are present at more than about 5 weight percent of the feedstock. 
     
     
         20 . The method according to  claim 1 , wherein the particulate feedstock carbon-containing polymeric materials are comprised of a mixture of cellulosic material and synthetic polymer. 
     
     
         21 . The method according to  claim 1 , wherein the feedstock contains about 15 to about 20 percent by weight water 
     
     
         22 . The method according to  claim 1 , including the additional step of using shock waves to break up long chain polymers into shorter chain polymers