KR-102963992-B1 - WASTE PLASTIC HYDROLYSIS PROCESS

Abstract

The present invention relates to a waste plastic hydrolysis process. Specifically, the present invention relates to a waste plastic hydrolysis process comprising: S1) a step of introducing waste plastic, water, and a metal salt of an aliphatic ( C4 - C20 ) carboxylic acid into a reactor and mixing them to produce a mixture; S2) a step of hydrolyzing the mixture to produce pyrolysis oil; and S3) a step of purifying the pyrolysis oil.

Inventors

• 강기혁
• 서필원
• 박선영
• 김도경
• 윤다님

Assignees

• 한국화학연구원

Dates

Publication Date

20260513

Application Date

20230927

Claims (12)

1. S1) A step of introducing waste plastic, water, and a catalyst precursor into a reactor and mixing them to produce a mixture; S2) A step of producing pyrolysis oil by hydrolyzing the above mixture at 250 to 500 ℃; S3) A waste plastic hydrolysis process comprising the step of refining the above pyrolysis oil; A waste plastic hydrolysis process in which the catalyst precursor comprises an aliphatic carboxylic acid metal salt having C4 to C20 carbon atoms.
2. In Article 1, A waste plastic hydrolysis process in which the metal of the above-mentioned aliphatic carboxylic acid metal salt comprises one or more selected from Ni, Mo, and Fe.
3. delete
4. In Article 1, A waste plastic hydrolysis process in which the above-mentioned aliphatic carboxylic acid metal salt comprises one or more selected from Ni-octoate, Mo-octoate, and Fe-octoate.
5. In Article 1, A waste plastic hydrolysis process in which the mixing in step S1) above is carried out at 150 to 200 ℃.
6. delete
7. In Article 1, A waste plastic hydrolysis process in which the hydrolysis reaction in step S2) above is carried out at 50 to 200 bar.
8. In Article 1, A waste plastic hydrolysis process comprising 10 to 100 parts by weight of water per 100 parts by weight of waste plastic in step S1) above.
9. In Article 1, A waste plastic hydrolysis process in which the content of the catalyst precursor introduced in step S1) is 1,000 to 3,000 ppm based on waste plastic.
10. In Article 1, A waste plastic hydrolysis process in which the hydrolysis reaction in step S2) above is carried out for 1 to 12 hours.
11. In Article 1, A waste plastic hydrolysis process in which purification in step S3) above is performed by flash distillation or centrifugation.
12. In Article 1, A waste plastic hydrolysis process in which the mixture of catalyst and residual oil generated in step S3) is fed into step S1) and recycled.

Description

WASTE PLASTIC HYDROLYSIS PROCESS The present invention relates to a waste plastic hydrolysis process. Research is being conducted to process the aforementioned waste vinyl that is not included in the items collectible by the Environmental Corporation, such as conventional bale silage film, fertilizer bags, and reflective film, and in particular, research is being conducted to provide low-boiling point pyrolysis oil by pyrolyzing the aforementioned waste vinyl. Methods for decomposing the above waste plastics include thermal cracking process, fluid catalytic cracking process, hydrocracking process, supercritical water oxidation, and hydropyrolysis. The aforementioned supercritical water oxidation method has the advantage of faster efficiency in the oxidative decomposition of C-C bonds compared to general thermal decomposition rates due to the strong oxidative reactivity of supercritical water; however, it presents a serious problem of equipment corrosion due to the oxidizing, solubility, and diffusivity of supercritical water. In particular, since corrosiveness increases further when using feeds with high impurity levels, there is a limitation that only raw materials with almost no impurities can be used. In addition, in the case of the above hydrothermal decomposition, although the corrosiveness of the equipment is lower than that of the supercritical water oxidation method, the high content of impurities such as coke can clog the nozzles of the equipment, potentially causing equipment failure; consequently, it is difficult to perform a continuous process such as a batch reactor. Accordingly, while the reaction time can be reduced to suppress the generation of the aforementioned impurities, this may lead to problems such as a decrease in the efficiency of the decomposition reaction, so research is needed to overcome this. Figure 1 is a schematic diagram of the waste plastic hydrolysis process of the present invention. Figure 2 is an image of TEM-EDX analysis of catalyst particles derived from a metal precursor during the hydrolysis step. Figure 3 is a graph showing the distribution of gaseous/liquid/solid products of the pyrolysis oil after the hydrolysis step of the examples and comparative examples. Figure 4 is a graph showing the distribution of liquid products after the hydrolysis step of the examples and comparative examples. Figure 5 is a graph analyzing the reaction pathways after the hydrolysis step of the examples and comparative examples. Figure 6 is a graph showing the impurity content after the hydrolysis step of the examples and comparative examples. The present invention will be described in more detail below through specific examples or embodiments, including the attached drawings. However, the following specific examples or embodiments are merely references for the detailed description of the present invention and the present invention is not limited thereto and may be implemented in various forms. Furthermore, unless otherwise defined, all technical and scientific terms have the same meaning as generally understood by one of the art to which the present invention pertains. The terms used in the description of the present invention are merely for the purpose of effectively describing specific embodiments and are not intended to limit the present invention. Additionally, the singular form used in the specification and the appended claims may be intended to include the plural form unless specifically indicated otherwise in the context. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. In addition, in the present invention, Naphtha means a C6 - C10 carbon compound, MD is an abbreviation for Middle distillate and means a C10 - C20 carbon compound, VGO is an abbreviation for Vacuum gas oil and means a C20 - C40 carbon compound, and VR is an abbreviation for Vacuum residue and means a carbon compound of C40 or higher. The present invention provides a waste plastic hydrolysis process comprising: S1) introducing waste plastic, water, and a catalyst precursor into a reactor and mixing them to produce a mixture; S2) reacting the mixture with hydrolysis to produce pyrolysis oil; and S3) purifying the pyrolysis oil, wherein the catalyst precursor comprises an aliphatic metal salt of a carboxylic acid. The above waste plastic hydrothermal decomposition process has the advantage of reducing the generation of CO or CO2 compared to the existing hydrothermal decomposition method, without causing equipment corrosion due to the oxidative, solubility, and diffusivity of the conventional supercritical oxidation reaction. In addition, the above-mentioned waste plastic hydrolysis process has the advantage of maximizing the yield of VGO while simultaneously suppressing the generation of impurities such as coke as much as possible. In other words, the present inv