Method and system for producing refined hydrocarbons from waste plastic pyrolysis oil
Embodiments of the present disclosure relate to a method and system for producing refined hydrocarbons from waste plastic pyrolysis oil. The method 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 method 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 a low content of impurities and a low content of olefins from waste plastic pyrolysis oil.
1. A method for producing refined hydrocarbons from waste plastic pyrolysis oil, the method comprising:
a dehydration operation applying a voltage to a first mixed solution comprising waste plastic pyrolysis oil, washing water, and a demulsifier to provide a dehydrated solution;
a hydrotreating operation hydrotreating a second mixed solution comprising the dehydrated solution and a sulfur source to produce a stream comprising refined oil;
a gas-liquid separation operation separating the stream to produce a gas stream comprising hydrogen gas and a liquid stream comprising the refined oil;
a recycling operation recycling the hydrogen gas in the gas stream directly to the hydrotreating operation; and
an isomerization operation subjecting the refined oil in the liquid stream to isomerization.
2. The method of claim 1 , wherein in the dehydration operation the waste plastic pyrolysis oil is included in a greater volume than the washing water.
3. The method of claim 2 , wherein the waste plastic pyrolysis oil and the washing water are included in the first mixed solution at a volume ratio of 1:0.001 to 1:0.5.
4. The method of claim 1 , wherein the waste plastic pyrolysis oil and the demulsifier are included 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 dehydrated 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 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 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 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 molybdenum, or molybdenum and one or more of nickel, cobalt, and tungsten are supported on a support.
17. The method of claim 1 , wherein the hydrotreating is performed under a pressure condition of 50 bar to 150 bar.
18. The method of claim 1 , wherein the isomerization operation further comprises distilling the refined oil before isomerization.
19. The method of claim 1 , wherein the refined oil from the liquid stream is mixed with petroleum hydrocarbons prior to the isomerization operation.