KR-102963482-B1 - Conversion of waste plastics into petrochemicals

KR102963482B1KR 102963482 B1KR102963482 B1KR 102963482B1KR-102963482-B1

Abstract

A process and system for converting waste plastic includes feeding waste plastic into a melting tank and heating the waste plastic in the melting tank to form molten plastic. The molten plastic is recovered from the melting tank and fed to a pyrolysis reactor. In the pyrolysis reactor, the molten plastic is heated to a pyrolysis temperature to produce pyrolysis oil products and liquid pitch products. Subsequently, the pyrolysis oil is separated into a pyrolysis gas fraction, a light pyrolysis oil fraction, an intermediate pyrolysis oil fraction, and a heavy pyrolysis oil fraction.

Inventors

차크라보티, 수딥토
페르날드, 다니엘, 티.
가이먼, 데이비드, 리
헤르바네크, 론
집, 리처드, 존
컴즈, 조니, 도일
린지, 보디, 린

Assignees

루머스 테크놀로지 엘엘씨

Dates

Publication Date: 20260511
Application Date: 20220114
Priority Date: 20210115

Claims (20)

As a method of converting waste plastic, Step of supplying waste plastic to a melting tank; A step of heating the waste plastic in the above melting tank to form heated molten plastic; A step of withdrawing the heated molten plastic from the melting tank and supplying the heated molten plastic to a pyrolysis reactor; A step of heating the heated molten plastic to a pyrolysis temperature in the above pyrolysis reactor to produce a pyrolysis oil product and a liquid pitch product; A step of separating the above pyrolysis oil product into a pyrolysis gas fraction, a light pyrolysis oil fraction, an intermediate pyrolysis oil fraction, and a heavy pyrolysis oil fraction; A step of dividing at least one of the above intermediate pyrolysis oil fraction and the above heavy pyrolysis oil fraction into a first part and a second part, respectively; and The method comprises the step of mixing at least one of the first portion of the intermediate pyrolysis oil fraction and the first portion of the heavy pyrolysis oil fraction with the heated molten plastic. A method in which the above mixing is performed inside the melting tank or downstream of the melting tank and upstream of the pyrolysis reactor.
The method according to claim 1, wherein the waste plastic is provided to the melting tank as partially or completely melted waste plastic recovered from the extruder, and the method further comprises the step of partially or completely melting the waste plastic of the extruder.
The method of claim 1 further comprises the step of controlling the temperature of the pyrolysis reactor to limit the temperature of the heated molten plastic to a temperature below the temperature at which charcoal or coke is formed, wherein the temperature of the pyrolysis reactor is within the range of 350℃ to 700℃.
In claim 1, the step of dividing the heated molten plastic into a first part and a second part; A step of mixing the above second portion with the waste plastic located upstream of the melting tank; and A method further comprising the step of supplying the above-mentioned first portion to the above-mentioned pyrolysis reactor.
A method according to claim 1, further comprising the step of contacting the waste plastic with nitrogen at a temperature sufficient to remove water from the waste plastic before supplying the waste plastic to the melting tank.
In claim 1, the step of dividing the heavy pyrolysis oil fraction into a first part and a second part; and A method further comprising the step of supplying a second portion of the above heavy pyrolysis oil fraction to the melting tank.
In claim 1, the step of dividing the intermediate pyrolysis oil fraction into a first part and a second part; and A method further comprising the step of quenching the pyrolysis oil recovered from the pyrolysis reactor using a second portion of the intermediate pyrolysis oil fraction as a quenching medium.
In claim 1, the step of dividing only the heavy pyrolysis oil fraction into a first part and a second part; and The method includes the step of mixing a first portion of the above heavy pyrolysis oil fraction with the above heated molten plastic, A method further comprising the step of performing the above mixing downstream of the melting tank and upstream of the pyrolysis reactor.
A method according to claim 1, further comprising the step of providing heat directly or indirectly to one or both of the melting tank or the pyrolysis reactor through the combustion of the pyrolysis gas fraction.
A method according to claim 1, further comprising the step of mixing an alkaline reagent with the heated molten plastic downstream of the melting tank and upstream of the pyrolysis reactor, reacting the alkaline reagent with chlorine contained in the heated molten plastic to form an alkaline salt, and recovering the alkaline salt along with the liquid pitch product.
A method according to claim 1, further comprising the step of withdrawing a steam stream from the melting tank and optionally treating the steam stream to remove any halogen contained therein.
As a system for pyrolyzing waste plastic, melting tank; and Includes a pyrolysis reactor, The above-mentioned melting tank is, An inlet configured to receive a feed stream containing waste plastic from a waste plastic supply system; A heating system configured to heat the waste plastic from a supply temperature to a melting temperature to produce molten plastic; and It includes an outlet configured to output the molten plastic, and The above pyrolysis reactor is, An inlet configured to receive the molten plastic; A heating system configured to heat the molten plastic to a pyrolysis temperature; A first outlet for recovering pyrolysis oil; A second outlet for recovering pitch products; A control system configured to control the heating system to limit the temperature of the molten plastic to a temperature for the production of the pitch product; comprising A separation system configured to separate the above pyrolysis oil into a pyrolysis gas fraction, a light pyrolysis oil fraction, an intermediate pyrolysis oil fraction, and a heavy pyrolysis oil fraction; and A flow line and mixing system configured to mix with the molten plastic by supplying at least one of the above-mentioned intermediate pyrolysis oil fraction and the above-mentioned heavy pyrolysis oil fraction; further comprising A system in which the mixing system is provided inside the melting tank or positioned downstream of the melting tank outlet and upstream of the pyrolysis reactor inlet.
In paragraph 12, the waste plastic supply system comprises an extruder for partially or melting the waste plastic.
In claim 12, a flow line disposed between the melt tank outlet and the pyrolysis reactor inlet and configured to divide the molten plastic into a first portion and a second portion supplied to the pyrolysis reactor inlet; and; A system further comprising a mixing system configured to mix a second portion of the molten plastic with the waste plastic upstream of the inlet and downstream of the waste plastic supply system.
In Clause 12, the waste plastic supply system comprises a supply hopper and a screw conveyor, and the system, A nitrogen supply line and a nitrogen supply line for supplying nitrogen to at least one of the above-mentioned supply hopper and the above-mentioned screw conveyor; and A system further comprising a nitrogen heater configured to heat nitrogen to a temperature higher than 100℃.
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A system according to claim 12, further comprising a quenching system configured to quench the pyrolysis oil recovered through the first outlet as part of the intermediate pyrolysis oil fraction.
A system further comprising, in paragraph 12, a flow line configured to supply the pyrolysis gas fraction as fuel to a heater.

Description

Conversion of waste plastics into petrochemicals The embodiments of the present disclosure generally relate to converting waste plastics into petrochemicals, fuels, and other useful intermediates and products. Environmental concern regarding the need to recover and recycle waste plastics is rapidly increasing. However, plastic pyrolysis technology is still in the early stages of development in the industry. The embodiments of the present invention relate to a thermochemical process and system useful for converting waste plastics into petrochemical products, fuels, and other intermediates or final products. In one embodiment, the embodiments of the present invention relate to a process for converting waste plastic. The process comprises the steps of feeding waste plastic into a melting tank, and heating the waste plastic in the melting tank to form molten plastic. The molten plastic is recovered from the melting tank and fed to a pyrolysis reactor. In the pyrolysis reactor, the molten plastic is heated to a pyrolysis temperature to produce a pyrolysis oil product and a liquid pitch product. Subsequently, the pyrolysis oil is separated into a pyrolysis gas fraction, a light pyrolysis oil fraction, an intermediate pyrolysis oil fraction, and a heavy pyrolysis oil fraction. In another aspect, embodiments of the present invention relate to a system for pyrolyzing waste plastic. The system comprises a melting tank having an inlet configured to receive a feed stream containing waste plastic from a waste plastic feed system. The melting tank further comprises a heating system configured to heat the waste plastic from a feed temperature to a melting temperature to produce molten plastic, and an outlet configured to output the molten plastic. The system for pyrolyzing waste plastic further comprises a pyrolysis reactor having an inlet configured to receive the molten plastic, a heating system configured to heat the molten plastic to a pyrolysis temperature, and a first outlet for recovering pyrolysis oil. The pyrolysis reactor further comprises a second outlet for recovering pitch products. The system further comprises a control system configured to control the heating system to limit the temperature of the molten plastic to a temperature for producing pitch products (and below a temperature at which significant char or coke is formed). FIG. 1 illustrates a simplified process flow diagram of a system according to one or more embodiments disclosed herein. FIG. 2 illustrates a simplified process flow diagram of a system according to one or more embodiments disclosed herein. FIG. 3 illustrates a simplified process flow diagram of a system according to one or more embodiments disclosed herein. The embodiments of the present invention relate to a thermochemical process for converting waste plastics into useful petrochemical products, fuels, and other intermediates or final products. The embodiments of the present invention also relate to the design and control of a pyrolysis reactor. Polymers capable of being pyrolyzed to form waste plastic pyrolysis oil may include thermoplastic resins, thermosetting resins, and elastomers. For example, waste materials that are pyrolyzed to form waste plastic pyrolysis oil may include, among many other thermoplastic resins, polystyrene, polypropylene, polyphenylene sulfide, polyphenylene oxide, polyethylene, polyetherimide, polyether ether ketone, polyoxymethylene, polyether sulfone, polycarbonate, polybenzimidazole, polylactic acid, nylon, and acrylic polymers such as polymethyl methacrylic acid (PMMA). Waste plastic pyrolysis oil useful herein may also be formed from various unsaturated or saturated elastomers and rubbers known in the art, such as polybutadiene, isoprene, styrene-butadiene, ethylene vinyl acetate, and many others. The embodiments of the present invention may be strong enough to process a portion of heteroatom-containing polymers, including those listed above as well as others known in the art, but the heteroatom content of the waste plastic pyrolysis oil produced should typically be less than 2 wt%, for example, less than 1 wt% or less than 0.5 wt%. Waste plastic can be converted into pyrolysis oil using a system according to an embodiment of the present invention. The system may include a melting tank and a pyrolysis reactor as main components. The system may also include, as described below, a waste plastic feeding system, a pyrolysis oil separation system, and one or more heating systems. Generally, a waste plastic feeding system is a system configured to provide a waste plastic feed to a melting tank, and since many different configurations can be used, it is not particularly limited. In some embodiments, the waste plastic feeding system may include a feeding hopper, which may be filled with a certain amount of waste plastic, such as chips, pellets, flakes, attenuated fibers, shredded plastic, and other forms of waste plastic that can be accepted from a recycler or