Production of hydrocarbon fuels from plastics

Abstract

Disclosed herein is a kiln 100 for use in the production of hydrocarbon fuels from plastics. The kiln 100 comprises a scrubber 200 in fluid communication with a reaction chamber 130 , the scrubber 200 being configured to condense hydrocarbons in the reaction chamber gas product stream 501 above a predetermined upper hydrocarbon range for returning to the reaction chamber 130 for further heating in the absence of oxygen. Also disclosed herein is a method of converting waste plastics to a commercially-useful form by way of diesel or the like. The method comprises treating a crude fuel produced from plastics in a pyrolytic process with a first extraction step comprising counterflow liquid-liquid extraction, and a second extraction step comprising counterflow extraction of solvents from the first extraction step.

1 .- 44 . (canceled) 
     
     
         45 . A method for deriving fuel from plastics, the method comprising subjecting a quantity of plastics to a pyrolytic process, thereby to convert at least a portion of the plastics to a crude fuel; and extracting the fuel in a directly usable form by way of:
 a first extraction step comprising counterflow liquid-liquid extraction using one or more extraction solvents to extract one or more impurities from the crude fuel; and   a second extraction step comprising counterflow extraction of resultant contaminated extraction solvent(s) from the first extraction step.   
     
     
         46 . The method according to  claim 45 , wherein the second extraction step comprises changing the polarity of the resultant contaminated extraction solvent(s), thereby causing the resultant contaminated extraction solvent(s) to reject the extracted one or more impurities; and removing the rejected one or more impurities, thereby resulting in decontaminated extraction solvent(s). 
     
     
         47 . The method according to  claim 46 , comprising reversing the polarity of the decontaminated extraction solvent(s). 
     
     
         48 . The method according to  claim 46 , wherein the polarity of the resultant contaminated extraction solvent(s) is changed by addition of one or more polar compounds thereto; and wherein the polarity of the decontaminated extraction solvent(s) is reversed by distilling the one or more polar compounds therefrom to produce purified extraction solvent(s) for reuse in the first extraction step. 
     
     
         49 . The method according to  claim 48 , comprising collecting the one or more polar compounds distilled from the contaminated extraction solvent(s) for reuse in the method. 
     
     
         50 . The method according to  claim 45 , wherein the second extraction step comprises adding a light end non-polar solvent, or a mixture of light end non-polar solvents, to the extraction solvent(s) obtained from the first extraction step to extract therefrom aromatics and compounds of similar polarity to that of the light end non-polar solvent(s); and then removing the light end non-polar solvent(s) by distillation. 
     
     
         51 . The method according to  claim 45 , wherein the extraction solvent(s) comprise(s) one or more solvents selected from the group consisting of: N-methyl-2-pyrrolidone; and dipolar aprotic solvents. 
     
     
         52 . The method according to  claim 45 , comprising purifying the resultant contaminated extraction solvent(s) for reuse in the first extraction step. 
     
     
         53 . The method of  claim 52 , wherein purification of the resultant contaminated extraction solvent(s) is performed in a substantially continuous manner to provide for substantially continuous operation of the first and second extraction steps. 
     
     
         54 . The method according to  claim 52 , wherein purification of the resultant contaminated extraction solvent(s) comprises the resultant contaminated extraction solvent(s) entering a rising film evaporator under vacuum. 
     
     
         55 . The method according to  claim 45 , wherein, in the counterflow extraction of the first extraction step, the extraction solvent(s) enter(s) the top of a packed column and the crude fuel enters the bottom of the packed column. 
     
     
         56 . The method according to  claim 55 , wherein the resultant contaminated extraction solvent(s) carrying the impurities exit(s) the bottom of the packed column, and purified fuel exits the top of the packed column. 
     
     
         57 . The method according to  claim 45 , wherein the fuel is a diesel blend. 
     
     
         58 . The method according to  claim 45 , wherein the pyrolytic process by which the plastics are converted to the crude fuel takes place at from about 300° C. to about 450° C., over a period of about 30 minutes. 
     
     
         59 . The method according to  claim 45 , wherein the first and second extraction steps take place at substantially ambient pressure, at about 80° C. and over a counterflow extraction period of less than about 20 minutes. 
     
     
         60 . The method according to  claim 45 , wherein the crude fuel is a hydrocarbon fuel obtained from plastics processed using a kiln comprising:
 a reaction chamber;   a feed inlet for feeding plastics feed material into the reaction chamber;   a heater for heating the reaction chamber; and   a scrubber in direct fluid communication with the reaction chamber;   wherein the kiln is configured such that plastics feed material in the reaction chamber is heated in an absence of oxygen thereby to decompose at least a portion of the plastics feed material into a reaction chamber gas product stream comprising hydrocarbons suitable for use as fuel, and   wherein the scrubber is configured to remove hydrocarbons in the reaction chamber gas product stream above a predetermined upper hydrocarbon range for returning to the reaction chamber for further heating in the absence of oxygen.