Production of hydrocarbon fuels from waste plastic

Abstract

The present invention relates to a method for producing fuel and additional hydrocarbons from waste plastic comprising the steps of providing at least one plastic material; exposing said at least one plastic material to a primary cracking to obtain a first hydrocarbon fluid; said first hydrocarbon fluid being a gas; exposing said first hydrocarbon gas to a catalytic hydrogenation to obtain a second hydrocarbon fluid; fractional separation of said second hydrocarbon fluid to obtain at least one final product. The present invention further relates to a waste recycling system for recycling waste plastic into fluid hydrocarbon compounds.

1 . A method for producing fuel and additional hydrocarbons from waste plastic comprising the steps of
 providing at least one plastic material;   exposing said at least one plastic material to a primary cracking to obtain a first hydrocarbon fluid; said first hydrocarbon fluid being a gas;   exposing said first hydrocarbon gas to a catalytic hydrogenation to obtain a second hydrocarbon fluid;   fractional separation of said second hydrocarbon fluid to obtain at least one final product.   
     
     
         2 . The method according to  claim 1  further comprising a step of condensation after said step of catalytic hydrogenation, wherein said second hydrocarbon fluid is obtained via at least said steps of catalytic hydrogenation and condensation and wherein said second hydrocarbon fluid is a multi-phase hydrocarbon fluid. 
     
     
         3 . The method according to  claim 2  further comprising a step of separation after said step of condensation, wherein said second hydrocarbon fluid is obtained at least via said steps of catalytic hydrogenation, condensation and separation and wherein said second hydrocarbon fluid is a first hydrocarbon liquid obtained from said multi-phase hydrocarbon fluid during separation. 
     
     
         4 . The method according to any of the preceding claims further comprising a step of pre-hydrogenation catalytic cracking performed prior to the step of catalytic hydrogenation, and wherein said first hydrocarbon fluid is obtained at least via said steps of primary cracking and pre-hydrogenation catalytic cracking. 
     
     
         5 . The method according to any of the preceding claims further comprising a step of post-hydrogenation catalytic cracking performed after the step of catalytic hydrogenation and wherein said second hydrocarbon fluid is obtained at least via said steps of catalytic hydrogenation and post-hydrogenation catalytic cracking. 
     
     
         6 . The method according to  claim 3  wherein said separation further results in the formation of a first non-condensable hydrocarbon gas and wherein at least a part of said first non-condensable hydrocarbon gas is recirculated to and burnt in a gas burner to provide heat to said primary cracking. 
     
     
         7 . The method according to  claim 6 , wherein said at least a part of said first non-condensable hydrocarbon gas is exposed to further processing before being burnt such as further condensation and separation. 
     
     
         8 . The method according to any of the preceding claims, wherein three final products are obtained from said fractional separation step, these products being a light fraction such as mainly C6 to C10; a medium fraction such as mainly C11 to C20 and a heavy fraction such as mainly C21 and above. 
     
     
         9 . The method according to  claim 8 , wherein said light fraction is condensed and optionally separated resulting in at least a light non-condensable hydrocarbon gas, and wherein at least a part of said light non-condensable hydrocarbon gas is recirculated to and burnt in a gas burner to provide heat to said primary cracking. 
     
     
         10 . The method according to any of the preceding claims wherein said at least one plastic material is HDPE, LDPE, PP and/or PS. 
     
     
         11 . The method according to any of the preceding claims wherein said primary cracking is performed by anaerobic thermal cracking. 
     
     
         12 . The method according to any of the preceding claims wherein said primary cracking is performed at a temperature between 300° C. to 550° C., preferably between 380° C. and 460° C., such as around 420° C. . 
     
     
         13 . The method according to any of the preceding claims, wherein said primary cracking is performed at a pressure range of 0.1 to 10 bar, preferably in the range of 0.7 to 2 bar, such as around 1 bar. 
     
     
         14 . The method according to any of the preceding claims, wherein said primary cracking is performed without catalysts. 
     
     
         15 . The method according to any of the preceding claims, wherein said primary cracking comprises minerals to reduce the reaction temperature and/or capture elements such as Cl or S. 
     
     
         16 . The method according to any of the preceding claims further comprising filtering and optionally cooling after the step of primary cracking. 
     
     
         17 . The method according to any of the preceding claims, wherein said catalytic hydrogenation is performed at operating temperatures between 150-280° C., preferably between 190-230° C., such as around 200° C. 
     
     
         18 . The method according to any of the preceding claims, wherein said catalytic hydrogenation is performed at a pressure range of 0.1 to 10 bar, preferably a range of 0.5 to 5 bar, like in the range of 0.7 to 2 bar, such as in the range of 0.9 to 1.1 bar, preferably around 1 bar. 
     
     
         19 . The method according to any of the preceding claims further comprising a step of circulating of said second hydrocarbon fluid to a holding tank prior to fractional separation. 
     
     
         20 . The method according to any one of the  claims 8 - 19 , wherein said heavy fraction is recycled to the step of primary cracking, catalytic cracking and/or catalytic hydrogenation or to said holding tank. 
     
     
         21 . The method according to  claim 20 , wherein said heavy fraction is exposed to a step of heavy fraction cracking before being recycled to the step of primary cracking, catalytic cracking and/or catalytic hydrogenation or to said holding tank. 
     
     
         22 . A waste recycling system for recycling waste plastic into fluid hydrocarbon compounds comprising
 a primary cracking reactor capable of receiving at least one plastic material and producing a first hydrocarbon fluid from said at least one plastic material by a primary cracking, said first hydrocarbon fluid being a gas;   a catalytic hydrogenation reactor capable of receiving said first hydrocarbon fluid and producing a second hydrocarbon fluid by catalytic hydrogenation,   and a fractional separator capable of fractional separation of said second hydrocarbon fluid to obtain at least one final product,   
       where said primary cracking reactor is in fluid connection with said catalytic hydrogenation reactor and said catalytic hydrogenation reactor is in fluid connection with said fractional separator. 
     
     
         23 . The system according to  claim 22 , wherein said system further comprises a condenser for producing said second hydrocarbon fluid together with said catalytic hydrogenation reactor and resulting in said second hydrocarbon fluid being a multi-phase hydrocarbon fluid, and wherein said catalytic hydrogenation reactor is further fluidly connected with said fractional separator through said condenser. 
     
     
         24 . The system according to  claim 23 , wherein said system further comprises a post-condensation separator for separating said multi-phase hydrocarbon fluid to provide a first hydrocarbon liquid and a first non-condensable hydrocarbon gas, and wherein said condenser is further fluidly connected with said fractional separator through said post-condensation separator. 
     
     
         25 . The system according to any of the  claims 22 - 24 , wherein said system further comprises a pre-hydrogenation catalytic cracking reactor, wherein said primary cracking reactor is further fluidly connected with said catalytic hydrogenation reactor through said pre-hydrogenation catalytic cracking reactor. 
     
     
         26 . The system according to any of the  claims 22 - 25 , wherein said system further comprises a post-hydrogenation catalytic cracking reactor, wherein said catalytic hydrogenation reactor is further fluidly connected with said fractional separator through said post-hydrogenation catalytic cracking reactor. 
     
     
         27 . The system according to any one of the  claims 22 - 26 , wherein said primary cracking reactor is an anaerobic thermal cracking reactor. 
     
     
         28 . The system according to any one of the  claims 22 - 27 , wherein said system further comprises a holding tank for storing the second hydrocarbon fluid prior to fractional separation, where said catalytic hydrogenation reactor is fluidly connected with the fractional separator at least via said holding tank. 
     
     
         29 . The system according to any one of the  claims 22 - 28 , wherein said system further comprises a gas burner for providing heat to said primary cracking reactor, said gas burner is fluidly connected with said post-condensation separator. 
     
     
         30 . The system according to any one of the  claims 22 - 29 , wherein the system further comprises a heavy fraction cracking reactor, said heavy fraction cracking reactor being in fluidly connection with said fractional separator for receiving a heavy fraction obtained from the fractional separation process and wherein said heavy fraction cracking reactor is further fluidly connected with said primary cracking reactor, said pre-hydrogenation catalytic cracking reactor, said post-hydrogenation catalytic cracking reactor and/or said catalytic hydrogenation reactor. 
     
     
         31 . The system according to any one of the  claims 22 - 30 , wherein the system further comprises a post-fractional separation condenser, a non-condensable gas separator and a gas burner, said post-fractional separation condenser being in fluidly connection with said fractional separator for receiving a light fraction obtained from the fractional separation process and wherein said post-fractional separation condenser is further fluidly connected with said non-condensable gas separator for separating a light non-condensable hydrocarbon gas; said non-condensable gas separator being further fluidly connected with said gas burner. 
     
     
         32 . Use of a system as described in any of the  claims 22 - 31  or a method as described in any of the  claims 1 - 21  for producing fuel and additional hydrocarbons from waste plastic. 
     
     
         33 . Use according to  claim 32 , wherein said fuel is Diesel.