Method and system for producing refined hydrocarbons from waste plastic pyrolysis oil

Abstract

Embodiments of the present disclosure relate to a method and system for producing refined hydrocarbons from waste plastic pyrolysis oil. The methods and system for producing refined hydrocarbons from waste plastic pyrolysis oil according to the embodiments of the present disclosure may minimize formation of an ammonium salt (NH 4 Cl) and may prevent an adhesion phenomenon of impurity particles in a reactor in a refining process of waste plastic pyrolysis oil containing impurities including chlorine and nitrogen. In addition, the methods and system for producing refined hydrocarbons according to the embodiments of the present disclosure may have excellent refining efficiency and may implement a long-term operation of a process because deactivation of a catalyst used in the process is prevented, and may produce refined hydrocarbons having excellent quality due to a significantly low content of impurities and a significantly low content of olefins may be provided from waste plastic pyrolysis oil.

1 . A method for producing refined hydrocarbons from waste plastic pyrolysis oil, the method comprising:
 a dehydration operation of applying a voltage to a first mixed solution comprising waste plastic pyrolysis oil, washing water, and a demulsifier to provide a dehydrated solution;   a first hydrotreating operation of subjecting, to a first hydrotreating, a second mixed solution comprising the dehydrated solution and a sulfur source to produce a first stream comprising refined oil;   a second hydrotreating operation of subjecting, to a second hydrotreating, the refined oil in the first stream to produce a second stream, and   a gas-liquid separation operation of separating the second stream to a gas stream comprising hydrogen gas and a liquid stream comprising the refined oil.   
     
     
         2 . The method of  claim 1 , wherein in the dehydration operation, the waste plastic pyrolysis oil is greater in volume than the washing water. 
     
     
         3 . The method of  claim 2 , wherein in the dehydration operation, the waste plastic pyrolysis oil and the washing water are in the first mixed solution at a volume ratio of 1:0.001 to 1:0.5. 
     
     
         4 . The method of  claim 1 , wherein in the dehydration operation, the waste plastic pyrolysis oil and the demulsifier are in the first mixed solution at a volume ratio of 1:0.000001 to 1:0.001. 
     
     
         5 . The method of  claim 1 , wherein the voltage is applied as an alternating current or a combination of an alternating current and a direct current. 
     
     
         6 . The method of  claim 1 , wherein the voltage is applied through at least one pair of vertical electrodes. 
     
     
         7 . The method of  claim 1 , further comprising, after the application of the voltage in the dehydration operation, removing a rag layer from the first mixed solution. 
     
     
         8 . The method of  claim 1 , wherein the dehydration operation is performed under a temperature condition of 20° C. to 300° C. 
     
     
         9 . The method of  claim 1 , wherein a ratio of a content of moisture in the waste plastic pyrolysis oil to a content of moisture in the dehydrated solution is 1:0.0001 to 1:0.9. 
     
     
         10 . The method of  claim 1 , wherein in the dehydration operation, the dehydrated solution is additionally dehydrated by condensation of moisture. 
     
     
         11 . The method of  claim 1 , wherein a weight ratio of nitrogen to chlorine in the second mixed solution is 1:1 to 1:10. 
     
     
         12 . The method of  claim 1 , wherein the sulfur source includes a sulfur-containing oil. 
     
     
         13 . The method of  claim 12 , wherein the sulfur-containing oil is included in an amount of less than 0.5 parts by weight with respect to 100 parts by weight of the dehydrated solution. 
     
     
         14 . The method of  claim 1 , wherein the sulfur source includes one or more sulfur-containing organic compounds selected from the group consisting of a disulfide-based compound, a sulfide-based compound, a sulfonate-based compound, and a sulfate-based compound. 
     
     
         15 . The method of  claim 1 , wherein the first hydrotreating is performed in the presence of a molybdenum-based hydrotreating catalyst. 
     
     
         16 . The method of  claim 15 , wherein the molybdenum-based hydrotreating catalyst is a catalyst in which a molybdenum-based metal, or a metal including one or two or more selected from nickel, cobalt, and tungsten, and a molybdenum-based metal are supported on a support. 
     
     
         17 . The method of  claim 1 , wherein the first hydrotreating operation is performed under a pressure condition of 50 bar to 150 bar. 
     
     
         18 . The method of  claim 1 , further comprising, after the gas-liquid separation, washing the gas stream with water and recycling the hydrogen gas in the gas stream to the first hydrotreating operation. 
     
     
         19 . The method of  claim 1 , wherein in the second hydrotreating operation, a refined fraction separated by distilling the refined oil in the first hydrotreating operation is subjected to the second hydrotreating. 
     
     
         20 . The method of  claim 1 , wherein in the second hydrotreating operation, mixed oil obtained by mixing the refined oil in the liquid stream and petroleum hydrocarbons is subjected to the second hydrotreating.