Device for producing low-carbon olefin from waste plastics

Abstract

The utility model discloses a device for producing low-carbon olefin from waste plastics. The device comprises a waste plastic hydro-liquefaction unit and a waste plastic oil catalytic cracking unit, the waste plastic hydro-liquefaction unit is used for completely converting waste plastic into plastic liquefied oil and hydrogenating to remove sulfur, nitrogen, chlorine and metal impurity elements; and the plastic liquefied oil is subjected to a catalytic cracking reaction by the waste plastic oil catalytic cracking unit to obtain low-carbon olefin products such as ethylene, propylene and butylene. According to the utility model, the waste plastics are converted into high-added-value low-carbon olefins to the maximum extent through online integrated coupling of waste plastic hydro-liquefaction and catalytic cracking.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of waste plastic recycling technology, specifically relates to a device for producing low carbon olefin from waste plastic. BACKGROUND

[0002] The high-value utilization of waste plastics is one of the effective ways to reduce environmental pollution and improve resource utilization efficiency. Chemical recycling technology is considered as an "upgraded" waste plastic utilization method that can realize closed-loop recycling. Through technologies such as thermal cracking, thermal cracking, catalytic cracking, and catalytic cracking, waste plastics are converted into chemicals or liquid fuel oil.

[0003] Currently, waste plastic chemical recycling mainly relies on thermal cracking and catalytic pyrolysis.

[0004] The processing method and processing system for fluidized cracking of waste plastic with publication number CN117660038 A, the liquefied waste plastic obtained by the liquefaction unit, the liquefied waste plastic oil obtained by the viscosity reduction cracking unit, enters the contact cracking reaction unit and the fluidized contact agent for cracking reaction, and separates to obtain dry gas, liquefied gas, gasoline fraction, diesel fraction and wax oil fraction. The patent can realize continuous processing of waste plastic, but there are problems such as high impurity content of liquefied waste plastic oil, poor performance of catalyst, and low added value of products.

[0005] In summary, the defects of the prior art are that the waste plastic impurities Cl and Si have high content, which directly contact with the catalytic cracking catalyst, and there are problems such as easy poisoning of the catalyst and serious corrosion of the equipment. UTILITY MODEL CONTENT

[0006] In order to overcome the above technical problems, the purpose of the utility model is to provide a device for producing low carbon olefin from waste plastic, which integrates and couples online waste plastic hydrogenation liquefaction and catalytic cracking to maximize the conversion of waste plastic into high value-added low carbon olefin.

[0007] In order to achieve the above purpose, the utility model adopts the technical scheme of:

[0008] A device for producing low carbon olefin from waste plastic, comprising a waste plastic hydrogenation liquefaction unit and a waste plastic oil catalytic cracking unit;

[0009] The waste plastic hydrogenation liquefaction unit completely converts waste plastic into plastic liquefied oil through a hydrogenation liquefaction reactor 2, while hydrogenating and removing sulfur, nitrogen, chlorine and metal impurity elements;

[0010] The waste plastic oil catalytic cracking unit catalytically cracks the plastic liquefied oil to obtain ethylene, propylene and butene low carbon olefin products.

[0011] The waste plastic hydroliquefaction unit comprises a raw material tank 1, a hydroliquefaction reactor 2 and a hot high-pressure separator 4;

[0012] The outlet of the raw material tank 1 is connected with the inlet of the hydroliquefaction reactor 2, the outlet of the hydroliquefaction reactor 2 is connected with the hot high-pressure separator 4, and plastic liquefied oil is obtained;

[0013] The top outlet of the hot high-pressure separator 4 is connected with the inlet of the catalytic cracking reactor 7 for conveying the gas phase product 5, and the bottom outlet of the hot high-pressure separator 4 is connected with the inlet of the fractionating column 9.

[0014] The catalytic cracking unit comprises the catalytic cracking reactor 7 and the fractionating column 9, and the catalytic cracking reactor 7 converts the waste plastic liquefied oil into ethylene, propylene and butene low-carbon olefin products;

[0015] The outlet end of the catalytic cracking reactor 7 is connected with the inlet end of the fractionating column 9;

[0016] The bottom outlet end of the hot high-pressure separator 4 conveys the heavy fraction oil 6 to the inlet end of the fractionating column 9 through a pipeline.

[0017] The side line outlet end of the fractionating column 9 outputs the recycling oil 12, which is returned to the feed inlet end of the catalytic cracking reactor 7 through a pipeline.

[0018] The bottom outlet of the fractionating column 9 outputs the column bottom heavy oil 13, and the column bottom heavy oil 13 is partly conveyed to the bottom of the raw material tank 1 as the circulating heavy oil 14 and partly output as the external heavy oil 15.

[0019] The device has the advantages that:

[0020] 1. The device realizes material relay, heat complementation and process coupling through the online coupling of the waste plastic hydroliquefaction and catalytic cracking processes, has the advantages of short process flow, high product added value and strong market competitiveness.

[0021] 2. The device can not only effectively remove harmful impurities in the waste plastic under the hydrogenation condition, but also maximize the conversion of the waste plastic into liquefied oil, and can reduce the equipment corrosion, so that suitable raw materials are provided for the subsequent catalytic cracking device and the continuous and stable operation of the device is ensured.

[0022] 3. The device realizes the closed-loop recycling and high-value utilization of the waste plastic by converting the waste plastic into high-added-value low-carbon olefins through the two steps of hydroliquefaction and catalytic cracking. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The device is a structure schematic diagram.

[0024] Reference signs:

[0025] 1-Raw material tank; 2-Hydrogenation liquefaction reactor; 3-Reaction product; 4-Hot high-pressure separator; 5-Gas phase product; 6-Heavy distillate oil; 7-Catalytic cracking reactor; 8-Catalytic cracking reaction product; 9-Fracturing tower; 10-Dry gas; 11-Liquefied gas; 12-Recycled oil; 13-Bottom heavy oil; 14-Circulating heavy oil; 15-External heavy oil. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings.

[0027] like Figure 1 As shown, an apparatus for producing low-carbon olefins from waste plastics includes a waste plastic hydrogenation liquefaction unit and a waste plastic oil catalytic cracking unit.

[0028] The waste plastic hydrogenation liquefaction unit includes a feed tank 1, a hydrogenation liquefaction reactor 2, and a hot high-pressure separator 4. Waste plastic, catalyst, dechlorination agent, and heavy oil are mixed in the feed tank 1 to form a uniform slurry. The outlet of the feed tank 1 is connected to the bottom inlet of the waste plastic hydrogenation liquefaction reactor 2, the outlet of the hydrogenation liquefaction reactor 2 is connected to the inlet of the hot high-pressure separator 4, the top outlet of the hot high-pressure separator 4 is connected to the inlet of the catalytic cracking reactor 7, and the bottom outlet of the hot high-pressure separator 4 is connected to the inlet of the fractionation tower 9.

[0029] The waste plastic catalytic cracking unit includes a catalytic cracking reactor 7 and a fractionation tower 9. The gaseous product 5 from the top outlet of the hot high-pressure separator 4 enters the bottom inlet of the catalytic cracking reactor 7 and reacts with the high-temperature catalytic cracking catalyst. The catalytic cracking reaction product 8 is mixed with heavy distillate oil 6 and then enters the fractionation tower 9 to obtain dry gas 10, liquefied gas 11, recycled oil 12, and bottom heavy oil 13, respectively. The recycled oil 12 is returned to the inlet of the catalytic cracking reactor 7 to continue the reaction. Part of the bottom heavy oil 13 is returned to the feed tank 1 of the waste plastic hydrogenation liquefaction unit as recycled heavy oil 14, and the other part is output as external heavy oil 15.

[0030] Furthermore, the waste plastic raw material in the waste plastic hydrogenation liquefaction unit can be one or more of PP, PE, PS, PVC, and PET, with a maximum particle size not exceeding 150 micrometers.

[0031] Furthermore, the operating temperature of the waste plastic hydrogenation liquefaction unit is 380-450℃, the operating pressure is 1-10MPa, and the reaction space velocity is 0.1-3.0h. -1 The hydrogen-to-oil ratio is 500-2000 NL / kg.

[0032] Furthermore, the catalytic cracking unit operates at a temperature of 500-700℃, a catalyst-to-oil ratio of 10-30, a reaction time of 0.2-3 seconds, and a pressure of 0.1-0.3 MPa.

[0033] The working principle of the utility model is:

[0034] The waste plastic, catalyst, dechlorination agent and heavy oil enter the raw material tank 1, are stirred and prepared into uniform slurry, are sequentially delivered by the high-pressure pump, are mixed with hydrogen in the pipeline, are preheated by the heating furnace, enter the hydrogenation liquefaction reactor 2, carry out hydrogenation liquefaction reaction, the reaction product 3 enters the hot high-pressure separator 4 and is separated to obtain the gas phase product 5 and the heavy distillate oil 6, the gas phase product 5 can be directly or after condensation treatment as catalytic cracking raw material, enters the catalytic cracking reactor 7 entrance, the heavy distillate oil 6 is mixed with the catalytic cracking reaction product 8 and then enters the fractionating tower 9, is separated by the fractionating tower 9 to obtain the dry gas 10, the liquefied gas 11, the back-refining oil 12 and the bottom heavy oil 13, part of the bottom heavy oil returns to the waste plastic hydrogenation liquefaction unit raw material tank 1 as the circulating heavy oil 14, and the other part is output as the external heavy oil 15.

Claims

1. An apparatus for producing low carbon olefins from waste plastics, characterized in that, The unit comprises a waste plastic hydroliquefaction unit and a waste plastic oil catalytic cracking unit. The waste plastic hydroliquefaction unit completely converts waste plastic into plastic liquefied oil through a hydroliquefaction reactor (2), while removing sulfur, nitrogen, chlorine and metal impurities by hydrogenation. The waste plastic oil catalytic cracking unit performs catalytic cracking reaction on the plastic liquefied oil to obtain ethylene, propylene and butene low-carbon olefin products. The waste plastic hydroliquefaction unit comprises a raw material tank (1), a hydroliquefaction reactor (2) and a hot high-pressure separator (4). The outlet of the raw material tank (1) is connected with the inlet of the hydroliquefaction reactor (2), and the outlet of the hydroliquefaction reactor (2) is connected with the hot high-pressure separator (4) to obtain plastic liquefied oil. The top outlet of the hot high-pressure separator (4) is connected with the inlet of the catalytic cracking reactor (7) for conveying gas phase products (5), and the bottom outlet of the hot high-pressure separator (4) is connected with the inlet of the fractionating column (9).

2. The apparatus for producing low-carbon olefins from waste plastics according to claim 1, characterized in that, The catalytic cracking unit comprises a catalytic cracking reactor (7) and a fractionating column (9), and the catalytic cracking reactor (7) converts waste plastic liquefied oil into ethylene, propylene and butene low-carbon olefin products. The outlet end of the catalytic cracking reactor (7) is connected with the inlet end of the fractionating column (9). The bottom outlet end of the hot high-pressure separator (4) delivers heavy distillate oil (6) to the inlet end of the fractionating column (9) through a pipeline.

3. The apparatus for producing low-carbon olefins from waste plastics according to claim 2, characterized in that, The side line outlet end of the fractionating column (9) outputs recycled oil (12) which is returned to the feed inlet end of the catalytic cracking reactor (7) through a pipeline.

4. The apparatus for producing low carbon olefins from waste plastics according to claim 2, wherein, The bottom outlet of the fractionating column (9) outputs bottom heavy oil (13), and a part of the bottom heavy oil (13) is delivered as circulating heavy oil (14) to the bottom of the raw material tank (1) through a pipeline, and another part is output as external heavy oil (15).

Images