Device and method for oxidation treatment of polyurethane

Abstract

The invention belongs to the technical field of polyurethane waste treatment, and particularly relates to a device and method for oxidation treatment of polyurethane. The polyurethane oxidation treatment device comprises a polyurethane storage bin, a water purification tank, a preheater, an oxygen tank, a pressurizer and an oxidation kettle, a discharging opening of the polyurethane storage bin is communicated with a feeding opening of the oxidation kettle, and the polyurethane storage bin is used for conveying polyurethane waste into the oxidation kettle; purified water stored in the purified water tank is conveyed to the oxidation kettle after being heated by the preheater, and is used for providing supercritical water for the oxidation kettle; oxygen stored in the oxygen tank is pressurized by the pressurizer and then is conveyed to the oxidation kettle for providing high-pressure oxygen for the oxidation kettle. The device for oxidation treatment of polyurethane has the beneficial effects that the device for oxidation treatment of polyurethane can efficiently treat polyurethane under the low-temperature condition, meanwhile, pollutants such as nitrogen oxides can be prevented from being generated, and generated CO2 gas is purer and is convenient to capture so as to reduce the greenhouse effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyurethane waste treatment, and particularly relates to a device and method for oxidizing polyurethane. BACKGROUND

[0002] Based on the changes in physical and chemical properties of water when it is transformed into a supercritical state above its critical temperature (374℃) and critical pressure (22.1 MPa). In this state, the density of water is close to that of a liquid, but its physical and chemical properties change significantly, such as increased density, reduced viscosity, increased diffusion coefficient, and reduced dielectric constant. The viscosity and diffusion coefficient are even close to those of a gas, which enables oxygen and other oxidizing agents to rapidly and uniformly mix with organic matter in wastewater.

[0003] Supercritical water treatment of organic wastewater has relatively mature technology, however, in the field of solid waste, especially polyurethane and other polymer waste treatment, the advantages of supercritical water treatment have not been realized. In view of the advantages such as treatment efficiency, it is necessary to develop corresponding supercritical water treatment technology for polyurethane. SUMMARY

[0004] The application provides a device and method for oxidizing polyurethane, aiming to solve the problem that existing polyurethane waste is mainly treated by incineration, and NOx and CO are generated. X pollution emissions.

[0005] The first aspect of the application provides a device for oxidizing polyurethane, comprising a polyurethane storage bin, a clean water tank, a preheater, an oxygen tank, a pressure intensifier, and an oxidation kettle; The discharge port of the polyurethane storage bin is connected to the feed port of the oxidation kettle, for conveying polyurethane waste to the oxidation kettle; The clean water stored in the clean water tank is heated by the preheater and then conveyed to the oxidation kettle, for providing supercritical water to the oxidation kettle; The oxygen stored in the oxygen tank is pressurized by the pressure intensifier and then conveyed to the oxidation kettle, for providing high-pressure oxygen to the oxidation kettle.

[0006] The device for oxidizing polyurethane described in the application uses supercritical water as a medium to complete rapid oxidation of polyurethane under low temperature conditions. Due to the low temperature level, the energy consumption is low. Due to the characteristics of supercritical fluid, the treatment efficiency is high. Under this condition, the oxidation process does not produce pollutants such as nitrogen oxides and carbon monoxide.

[0007] According to some embodiments of the device for oxidizing polyurethane described in the application, the discharge port of the oxidation kettle is connected to the water inlet of the clean water tank.

[0008] According to some embodiments of the device for oxidizing polyurethane described in the application, an air outlet is provided on the clean water tank.

[0009] The second aspect of the present application provides a method for oxidizing polyurethane, which is performed by the device for oxidizing polyurethane according to the first aspect of the present application.

[0010] According to some embodiments of the method for oxidizing polyurethane, the polyurethane waste stored in the polyurethane storage bin is transported to the oxidation kettle, and at the same time, the water in the water tank is heated by the preheater and then transported to the oxidation kettle, and the oxygen in the oxygen tank is pressurized by the pressurizer and then transported to the oxidation kettle, and the oxidation reaction is performed.

[0011] According to some embodiments of the method for oxidizing polyurethane, the mass ratio of the polyurethane waste and the water transported to the oxidation kettle is 1: (10-15).

[0012] According to some embodiments of the method for oxidizing polyurethane, the mass ratio of the oxygen and the water transported to the oxidation kettle is 1: (5-7.5).

[0013] According to some embodiments of the method for oxidizing polyurethane, the temperature of the water transported to the oxidation kettle is 90-100℃.

[0014] According to some embodiments of the method for oxidizing polyurethane, the pressure of the oxygen transported to the oxidation kettle is 22-23MPa.

[0015] According to some embodiments of the method for oxidizing polyurethane, the temperature of the oxidation reaction is 374-400℃, the pressure of the oxidation reaction is 22.1-22.5MPa, and the time of the oxidation reaction is 0.8-1.5h.

[0016] The beneficial effects of the present application include that the device for oxidizing polyurethane can efficiently treat polyurethane under low temperature conditions, while avoiding the generation of pollutants such as nitrogen oxides, and the generated CO2 gas is more pure, which is convenient for capture to reduce the greenhouse effect. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The figure is a structural schematic diagram of the device for oxidizing polyurethane according to the present application. In the figure: 1, polyurethane storage bin; 2, preheater; 3, water tank; 4, oxygen tank; 5, pressurizer; 6, oxidation kettle. DETAILED DESCRIPTION

[0018] The embodiments of the present application are described in detail below, and the examples of the embodiments are exemplary and are intended to explain the present application, but cannot be understood as a limitation of the present application.

[0019] In this disclosure, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present disclosure. Exemplary representations of the above terms in this specification are not necessarily directed to the same embodiment or example. Moreover, the described particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. In addition, different embodiments or examples described in this specification and features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0020] The embodiment of the present application provides a device for oxidizing polyurethane, which comprises a polyurethane storage bin, a clean water tank, a preheater, an oxygen tank, a pressure device and an oxidation kettle. The discharge port of the polyurethane storage bin is connected with the feeding port of the oxidation kettle, and is used for conveying polyurethane waste to the oxidation kettle. The clean water stored in the clean water tank is heated by the preheater and then conveyed to the oxidation kettle, and is used for providing supercritical water to the oxidation kettle. The oxygen stored in the oxygen tank is pressurized by the pressure device and then conveyed to the oxidation kettle, and is used for providing high-pressure oxygen to the oxidation kettle.

[0021] The device for oxidizing polyurethane provided by the present application uses supercritical water as a medium, and completes rapid oxidation of polyurethane under low-temperature conditions. The device has low energy consumption due to the low temperature level. The device has high processing efficiency due to the characteristics of supercritical fluid. The oxidation process under the condition does not produce pollutants such as nitrogen oxides and carbon monoxide.

[0022] In some embodiments of the present application, the exhaust port of the oxidation kettle is connected with the water inlet of the clean water tank. After the polyurethane waste is treated by the oxidation kettle, carbon dioxide, water vapor and nitrogen are generated, and are discharged into the clean water tank. Due to pressure relief and temperature drop, the water vapor is converted into water, and the carbon dioxide and nitrogen are discharged into the atmosphere.

[0023] In some embodiments of the present application, the clean water tank is provided with an air outlet. The air outlet is arranged to discharge carbon dioxide and nitrogen.

[0024] The embodiment of the present application further provides a method for oxidizing polyurethane, which adopts the device for oxidizing polyurethane according to the first aspect of the present application to perform oxidation treatment.

[0025] In some embodiments of the present application, the method comprises the following steps: conveying the polyurethane waste stored in the polyurethane storage tank to the oxidation kettle; at the same time, conveying the water in the water tank to the oxidation kettle after being heated by the preheater, and conveying the oxygen in the oxygen tank to the oxidation kettle after being pressurized by the pressurizer; and performing an oxidation reaction. The method for oxidizing polyurethane described in the present application uses supercritical water as a medium to complete the rapid oxidation of polyurethane under low temperature conditions, has low energy consumption due to the low temperature level, has high treatment efficiency due to the characteristics of supercritical fluid, and does not produce pollutants such as nitrogen oxides and carbon monoxide in the oxidation process under this condition.

[0026] In some embodiments of the present application, the mass ratio of the polyurethane waste and water conveyed into the oxidation kettle is 1: (10-15), such as 1:10, 1:12, 1:13, 1:15, etc.

[0027] In some embodiments of the present application, the mass ratio of the oxygen and water conveyed into the oxidation kettle is 1: (5-7.5), such as 1:5, 1:6, 1:7, 1:7.5, etc.

[0028] In some embodiments of the present application, the temperature of the water conveyed into the oxidation kettle is 90-100℃. For example, 90℃, 93℃, 95℃, 98℃, 100℃, etc.

[0029] In some embodiments of the present application, the pressure of the oxygen conveyed into the oxidation kettle is 22-23MPa, such as 22MPa, 22.5MPa, 22.8MPa, 23MPa, etc.

[0030] In some embodiments of the present application, the temperature of the oxidation reaction is 374-400℃, the pressure of the oxidation reaction is 22.1-22.5MPa, and the time of the oxidation reaction is 0.8-1.5h. If the oxidation reaction temperature is higher than the range value (the same for the pressure), the conversion of the nitrogen element contained in the polyurethane to NOx will be promoted, and pollutants will be produced; if it is lower than the range value, the chemical reaction efficiency is low, and the oxidation and degradation of the polyurethane are not complete. x

[0031] The technical solutions of the present application are further described below in conjunction with the embodiments.

[0032] Embodiment 1 ​The device for oxidizing polyurethane comprises a polyurethane storage bin, a clean water tank, a preheater, an oxygen tank, a pressure device and an oxidation kettle. The discharge port of the polyurethane storage bin is connected with the feeding port of the oxidation kettle, and is used for conveying polyurethane waste to the oxidation kettle. The clean water stored in the clean water tank is heated by the preheater and then conveyed to the oxidation kettle, and is used for providing supercritical water to the oxidation kettle. The oxygen stored in the oxygen tank is pressurized by the pressure device and then conveyed to the oxidation kettle, and is used for providing high-pressure oxygen to the oxidation kettle.

[0033] The device described in the application processes polyurethane waste to generate water, carbon dioxide and nitrogen, which are discharged from the exhaust port of the oxidation kettle into the clean water tank. The water discharged into the clean water tank is reused, and the carbon dioxide and nitrogen discharged into the clean water tank are discharged from the gas outlet provided on the clean water tank.

[0034] Example 2 The method for oxidizing polyurethane comprises the following steps: conveying the polyurethane waste stored in the polyurethane storage bin to the oxidation kettle; at the same time, conveying the water in the clean water tank to the oxidation kettle after being heated to 100℃ by the preheater, and conveying the oxygen in the oxygen tank to the oxidation kettle after being pressurized to a pressure of 22.1 MPa by the pressure device; controlling the mass ratio of the polyurethane waste and the water conveyed into the oxidation kettle to be 1:10 (wherein the conveying amount of the polyurethane waste is 100 kg / h), and the mass ratio of the water and the oxygen to be 5.5:1, and oxidizing under the conditions of a reaction temperature of 374℃ and a pressure of 22.1 MPa for 1.4 h. The reaction process is as follows: (C 10 H8N2O2C6H 14 O3) n +O2→CO2+H2O+N2.

[0035] Example 3 The method for oxidizing polyurethane described in Example 3 is different from that of Example 2 only in that the temperature of the oxidation reaction in the process of oxidizing polyurethane described in Example 3 is different from that of Example 2.

[0036] The specific operation steps include: The method for oxidizing polyurethane comprises the following steps: conveying the polyurethane waste stored in the polyurethane storage bin to the oxidation kettle; at the same time, conveying the water in the clean water tank to the oxidation kettle after being heated to 100℃ by the preheater, and conveying the oxygen in the oxygen tank to the oxidation kettle after being pressurized to a pressure of 22.1 MPa by the pressure device; controlling the mass ratio of the polyurethane waste and the water conveyed into the oxidation kettle to be 1:10 (wherein the conveying amount of the polyurethane waste is 100 kg / h), and the mass ratio of the water and the oxygen to be 5.5:1, and oxidizing under the conditions of a reaction temperature of 374℃ and a pressure of 22.1 MPa for 1.4 h. The reaction process is as follows: (C 10 H8N2O2C6H 14 O3) n +O2→CO2+H2O+N2.

[0037] Example 4 The method for oxidizing polyurethane in Example 4 differs from that in Example 2 only in that the temperature of the oxidation reaction in the process of oxidizing polyurethane in Example 4 is different from that in Example 2.

[0038] The specific operation steps include: The polyurethane waste stored in the polyurethane storage bin is transported to the oxidation kettle; at the same time, the water in the clean water tank is heated to 100°C by the preheater and then transported to the oxidation kettle, and the oxygen in the oxygen tank is pressurized to a pressure of 22.1 MPa by the pressurizer and then transported to the oxidation kettle; the mass ratio of the polyurethane waste and water transported into the oxidation kettle is controlled to be 1:10 (wherein the transportation amount of the polyurethane waste is 100 kg / h), the mass ratio of the water and oxygen is controlled to be 5.5:1, and the oxidation reaction is carried out at a reaction temperature of 450°C and a pressure of 42.3 MPa for 1.4 h. The reaction process is as follows: (C 10 H8N2O2C6H 14 O3) n +O2→CO2+H2O+N2.

[0039] Example 5 The method for oxidizing polyurethane in Example 5 differs from that in Example 2 only in that the temperature of the oxidation reaction in the process of oxidizing polyurethane in Example 5 is different from that in Example 2.

[0040] The specific operation steps include: The polyurethane waste stored in the polyurethane storage bin is transported to the oxidation kettle; at the same time, the water in the clean water tank is heated to 100°C by the preheater and then transported to the oxidation kettle, and the oxygen in the oxygen tank is pressurized to a pressure of 22.1 MPa by the pressurizer and then transported to the oxidation kettle; the mass ratio of the polyurethane waste and water transported into the oxidation kettle is controlled to be 1:10 (wherein the transportation amount of the polyurethane waste is 100 kg / h), the mass ratio of the water and oxygen is controlled to be 5.5:1, and the oxidation reaction is carried out at a reaction temperature of 300°C and a pressure of 8.5 MPa for 1.4 h. The reaction process is as follows: (C 10 H8N2O2C6H 14 O3) n +O2→CO2+H2O+N2.

[0041] Example 6 The method for oxidizing polyurethane in Example 6 differs from that in Example 2 only in that the time of the oxidation reaction in the process of oxidizing polyurethane in Example 6 is different from that in Example 2.

[0042] The specific operation steps include: The polyurethane waste stored in the polyurethane storage tank is transported to the oxidation kettle; at the same time, the water in the clean water tank is heated to 100℃ by the preheater and then transported to the oxidation kettle, and the oxygen in the oxygen tank is pressurized to a pressure of 22.1 MPa by the pressure intensifier and then transported to the oxidation kettle; the mass ratio of the polyurethane waste and water transported into the oxidation kettle is controlled to be 1:10 (wherein the transportation amount of the polyurethane waste is 100 kg / h), and the mass ratio of the water and oxygen is controlled to be 5.5:1, and the oxidation reaction is carried out at a reaction temperature of 374℃ and a pressure of 22.1 MPa for 2.5 h. The reaction process is as follows:(C 10 H8N2O2C6H 14 O3) n +O2→CO2+H2O+N2.

[0043] Example 7 The method for oxidizing the polyurethane described in Example 7 is different from that of Example 2 only in that the oxidation reaction time in the process of oxidizing the polyurethane described in Example 7 is different from that of Example 2.

[0044] The specific operation steps include: The polyurethane waste stored in the polyurethane storage tank is transported to the oxidation kettle; at the same time, the water in the clean water tank is heated to 100℃ by the preheater and then transported to the oxidation kettle, and the oxygen in the oxygen tank is pressurized to a pressure of 22.1 MPa by the pressure intensifier and then transported to the oxidation kettle; the mass ratio of the polyurethane waste and water transported into the oxidation kettle is controlled to be 1:10 (wherein the transportation amount of the polyurethane waste is 100 kg / h), and the mass ratio of the water and oxygen is controlled to be 5.5:1, and the oxidation reaction is carried out at a reaction temperature of 374℃ and a pressure of 22.1 MPa for 0.5 h. The reaction process is as follows:(C 10 H8N2O2C6H 14 O3) n +O2→CO2+H2O+N2.

[0045] Example 8 The method for oxidizing the polyurethane described in Example 8 is different from that of Example 2 only in that the oxidation reaction time in the process of oxidizing the polyurethane described in Example 8 is different from that of Example 2.

[0046] The specific operation steps include: Polyurethane waste stored in the polyurethane storage silo is transported to the oxidation reactor; simultaneously, water in the purified water tank is preheated to 100°C and then transported to the oxidation reactor, while oxygen in the oxygen tank is pressurized to 22.1 MPa and then transported to the oxidation reactor; the mass ratio of polyurethane waste to water transported to the oxidation reactor is controlled at 1:10 (with a polyurethane waste transport rate of 100 kg / h), and the mass ratio of water to oxygen is 5.5:1. The oxidation reaction is carried out for 3.5 hours at a reaction temperature of 374°C and a pressure of 22.1 MPa. The reaction process is as follows: (C 10 H8N2O2C6H 14 O3) n +O2→CO2+H2O+N2.

[0047] An evaluation of the effect of the oxidative treatment method for polyurethane described in this application: The results are shown in Table 1.

[0048] Note: Product NO x Molar ratio / % refers to the conversion of nitrogen to NO in polyurethane. x molar percentage; The N2 molar ratio of the product refers to the molar percentage of nitrogen in the polyurethane that has been converted into N2. Other impurity nitrogen product molar ratio / % refers to the molar percentage of nitrogen in polyurethane converted into other impurity nitrogen products.

[0049] Table 1

[0050] Table 1 shows that when the reaction temperature is 374-385℃, the degradation rate of polyurethane is 100%; the nitrogen in the polyurethane is completely converted into nitrogen gas. When the reaction temperature is too high (the reaction temperature in Example 4 is 450℃), the nitrogen in the polyurethane undergoes NO oxidation. X The conversion reaction produces pollutants; when the reaction temperature is too low (the reaction temperature in Example 5 is 300°C), the polyurethane is not completely degraded and the nitrogen element is not completely oxidized and converted, resulting in nitrogen-containing impurity products such as toluene diisocyanate and NH3.

[0051] A comparison of Examples 1 and 6-8 shows that reaction time is a key factor affecting the polyurethane oxidation efficiency described in this application. If the polyurethane has already completely degraded within the set reaction time, extending the reaction time will not provide further benefit to the polyurethane degradation, thus reducing the processing efficiency of the polyurethane per unit time; insufficient reaction time will lead to incomplete polyurethane degradation.

[0052] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. An apparatus for oxidizing polyurethane, characterized in that, This includes a polyurethane storage tank, a clean water tank, a preheater, an oxygen tank, a pressurizer, and an oxidation reactor; The outlet of the polyurethane storage silo is connected to the inlet of the oxidation reactor, and is used to transport polyurethane waste into the oxidation reactor. The purified water stored in the purified water tank is heated by the preheater and then transported to the oxidation reactor to provide supercritical water to the oxidation reactor; The oxygen stored in the oxygen tank is pressurized by a pressurizer and then delivered to the oxidation reactor to provide high-pressure oxygen to the oxidation reactor.

2. The apparatus for oxidizing polyurethane according to claim 1, characterized in that, The exhaust port of the oxidation reactor is connected to the inlet of the purified water tank.

3. The apparatus for oxidizing polyurethane according to claim 1, characterized in that, The water purification tank is equipped with an air outlet.

4. A method for oxidizing polyurethane, characterized in that, The oxidation treatment is performed using the apparatus for oxidizing polyurethane as described in any one of claims 1-3.

5. The method for oxidizing polyurethane according to claim 4, characterized in that, Includes the following steps: Polyurethane waste stored in the polyurethane storage silo is transported to the oxidation reactor; at the same time, water in the clean water tank is heated by a preheater and then transported to the oxidation reactor, and oxygen in the oxygen tank is pressurized by a pressurizer and then transported to the oxidation reactor; the oxidation reaction is carried out.

6. The method for oxidizing polyurethane according to claim 5, characterized in that, The mass ratio of polyurethane waste to water transported to the oxidation reactor is 1:(10-15).

7. The method for oxidizing polyurethane according to claim 5, characterized in that, The mass ratio of oxygen to water supplied to the oxidation reactor is 1:(5-7.5).

8. The method for oxidizing polyurethane according to claim 5, characterized in that, The temperature of the water supplied to the oxidation reactor is 90-100℃.

9. The method for oxidizing polyurethane according to claim 5, characterized in that, The pressure of the oxygen supplied to the oxidation reactor is 22-23 MPa.

10. The method for oxidizing polyurethane according to claim 5, characterized in that, The oxidation reaction is carried out at a temperature of 374-400℃, at a pressure of 22.1-22.5 MPa, and for a time of 0.8-1.5 h.

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