RTO waste heat comprehensive utilization device and method for isophthalonitrile process tail gas treatment

Abstract

The invention provides an RTO waste heat comprehensive utilization device and method for isophthalonitrile process tail gas treatment. The RTO waste heat comprehensive utilization device is characterized in that a waste heat utilization high-temperature flue gas pipeline with a waste heat utilization unit is arranged between an RTO combustion chamber and an outlet mixing box in parallel; the waste heat utilization stop valve is used for controlling the opening and closing of the waste heat utilization unit, so that the waste heat recovery can be effectively realized, the heat of the isophthalonitrile process tail gas is comprehensively utilized, the fuel is saved, the emission of pollutants is reduced, and the energy-saving and consumption-reducing effects are obvious while the environmental protection is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of pollutant treatment, and in particular to a device and method for comprehensive utilization of waste heat in a tail gas treatment process, and in particular to a device and method for comprehensive utilization of waste heat in an isophthalonitrile process tail gas treatment RTO. Background Art

[0002] The raw materials for synthesizing isophthalonitrile are meta-xylene, ammonia and air, which are subjected to ammoxidation reaction in a fluidized bed. The reaction requires an excess of about 50% ammonia, and the volume content of ammonia in the tail gas of the process is about 4%, and the content of other VOCs is about 1%. The existing technical means for treating isophthalonitrile tail gas mainly include absorption method, condensation method, adsorption method, incineration method, etc. Among them, the regenerator incineration method is a high-temperature pyrolysis treatment technology. The treated organic waste undergoes an oxidative combustion reaction in a regenerator. The harmful substances in the exhaust gas are oxidized and pyrolyzed at a high temperature of 760-1100°C and destroyed. The heat of the high-temperature gas is stored in the regenerator, and the next exhaust gas is preheated. After preheating, it enters the combustion chamber for oxidative pyrolysis. It is a treatment technology that can save fuel and achieve harmlessness of waste. The process has high heat exchange efficiency, low operating cost and high degree of automation. However, the ammonia content in the isophthalonitrile process tail gas is high and the exhaust gas calorific value is high. If it is not controlled, it is easy to cause the temperature to be difficult to control. The nitrogen oxides produced by the combustion of ammonia are high, and even cause great safety risks.

[0003] CN114321948A discloses a system and method for treating tail gas from an isophthalonitrile process, wherein the system comprises a process tail gas collection unit, a process tail gas mixing unit, an emergency treatment unit, an RTO unit, a tail gas denitration unit, a tail gas cooling unit and a tail gas emission unit; the process tail gas collection unit, the process tail gas mixing unit, the RTO unit, the tail gas denitration unit, the tail gas cooling unit and the tail gas emission unit are connected in sequence; the process tail gas collection unit is also directly connected to the tail gas emission unit through the emergency treatment unit. The tail gas from the RTO furnace after combustion is divided into three parts, the first part is directly discharged to the outlet mixing box, the second part returns to the inlet mixing box, and the third part passes through the second regenerator and the bottom cavity in the RTO furnace from top to bottom and then is discharged to the outlet mixing box.

[0004] However, as the inventors further studied, the temperature of the RTO furnace combustion chamber is 760-1100°C, while the temperature of the outlet mixing box is 250-350°C. The temperature difference of about 500°C causes the heat loss from the RTO furnace to the outlet mixing box to be still relatively large.

[0005] TO furnaces have a simple structure and no complex heat recovery system, so their maintenance and operation may be relatively straightforward. However, TO furnaces have low energy efficiency. Since direct-fired furnaces have no heat recovery mechanism, their energy efficiency is relatively low. During the combustion process, a large amount of heat energy is directly dissipated, resulting in high fuel consumption.

[0006] Therefore, it is necessary to develop a device and method for comprehensive utilization of waste heat from isophthalonitrile process tail gas treatment RTO to further improve the comprehensive utilization efficiency of waste heat and make full use of the heat of pollutants in the tail gas. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a device and method for comprehensive utilization of RTO waste heat in tail gas treatment of isophthalonitrile process. The key to the RTO waste heat comprehensive utilization device is to set a waste heat utilization high-temperature flue gas pipeline with a waste heat utilization unit in parallel between the RTO combustion chamber and the outlet mixing box, and control the opening and closing of the waste heat utilization unit by a waste heat utilization cut-off valve, which can effectively realize waste heat recovery, so that the heat of the isophthalonitrile process tail gas can be comprehensively utilized, fuel can be saved, and pollutant emissions can be reduced.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] One of the purposes of the present invention is to provide an isophthalonitrile process tail gas treatment RTO waste heat comprehensive utilization device, comprising: an RTO combustion chamber and an outlet mixing box, wherein a first high-temperature flue gas pipeline and a waste heat utilization high-temperature flue gas pipeline are arranged in parallel between the outlet of the RTO combustion chamber and the inlet of the outlet mixing box;

[0010] Among them, along the flue gas flow direction, a waste heat utilization shut-off valve and a waste heat utilization unit are sequentially arranged on the waste heat utilization high-temperature flue gas pipeline.

[0011] The device for comprehensive utilization of waste heat of RTO waste gas treatment of isophthalonitrile process of the present invention is mainly characterized in that a waste heat utilization high-temperature flue gas pipeline with a waste heat utilization unit is arranged in parallel between the RTO combustion chamber and the outlet mixing box, and the opening and closing of the waste heat utilization unit is controlled by a waste heat utilization cut-off valve, so that waste heat recovery can be effectively realized, so that the heat of the isophthalonitrile process tail gas can be comprehensively utilized, fuel can be saved, and the emission of pollutants can be reduced.

[0012] As a preferred technical solution of the present invention, the waste heat utilization high-temperature flue gas pipeline includes a second high-temperature flue gas pipeline and a third high-temperature flue gas pipeline arranged in parallel; the waste heat utilization unit includes a steam boiler and a TO furnace; the waste heat utilization shut-off valve includes a steam boiler high-temperature flue gas shut-off valve and a TO furnace high-temperature flue gas shut-off valve;

[0013] Along the flue gas flow direction, a steam boiler high-temperature flue gas shut-off valve and a steam boiler are sequentially arranged on the second high-temperature flue gas duct, and a TO furnace high-temperature flue gas shut-off valve and a TO furnace are sequentially arranged on the third high-temperature flue gas duct.

[0014] In the present invention, the waste heat utilization unit includes a steam boiler and a TO furnace arranged in parallel, that is, a first high-temperature flue gas duct, a second high-temperature flue gas duct with a steam boiler, and a third high-temperature flue gas duct with a TO furnace are arranged in parallel between the outlet of the RTO combustion chamber and the inlet of the outlet mixing box, and the waste heat of the RTO process tail gas is comprehensively utilized by generating steam for reuse through the steam boiler, and / or reducing the fuel consumption of the TO furnace through the TO furnace, so that the heat of the isophthalonitrile process tail gas is comprehensively utilized, while saving fuel and reducing the emission of pollutants.

[0015] As a preferred technical solution of the present invention, a steam boiler flue gas regulating valve is arranged on the second high-temperature flue gas pipeline between the steam boiler and the outlet mixing box.

[0016] As a preferred technical solution of the present invention, a TO furnace flue gas regulating valve is arranged on the third high-temperature flue gas duct between the TO furnace and the outlet mixing box.

[0017] As a preferred technical solution of the present invention, the first high-temperature flue gas duct is a circular duct or a square duct, and an insulation layer is provided inside the duct.

[0018] As a preferred technical solution of the present invention, the second high-temperature flue gas duct and the third high-temperature flue gas duct are respectively and independently circular ducts or square ducts, and a heat-insulating layer is provided inside the ducts.

[0019] As a preferred technical solution of the present invention, the steam boiler is a waste heat steam fire tube boiler, and the TO furnace is a direct-fired furnace.

[0020] It should be noted that the steam boiler described in the present invention is a waste heat steam fire tube boiler. Those skilled in the art can select the appropriate saturated steam pressure and boiler size according to the actual required heat exchange amount, and the present invention does not make too many restrictions here; the TO furnace is a direct-fired furnace, and the high-temperature flue gas inlet from the RTO combustion chamber is arranged at a position between the front and middle parts of the TO furnace.

[0021] The second object of the present invention is to provide a method for treating the RTO waste heat comprehensive utilization device using the isophthalonitrile process tail gas described in the first object, and the method includes the following contents:

[0022] The high-temperature flue gas from the RTO combustion chamber directly enters the outlet mixing box through the first high-temperature flue gas pipeline. At the same time, by controlling the opening and closing of the waste heat utilization cut-off valve, it is controlled whether part of the high-temperature flue gas from the RTO combustion chamber enters the waste heat utilization unit through the waste heat utilization high-temperature flue gas pipeline to achieve waste heat recovery, and finally enters the outlet mixing box;

[0023] Wherein, the temperature of the RTO combustion chamber is 760-1100°C, for example, 760°C, 800°C, 830°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1070°C or 1100°C, and preferably 830-1070°C. The temperature of the outlet mixing box is 250-350°C, for example, 250°C, 260°C, 280°C, 300°C, 310°C, 330°C or 350°C.

[0024] As a preferred technical solution of the present invention, the waste heat utilization high-temperature flue gas pipeline includes a second high-temperature flue gas pipeline and a third high-temperature flue gas pipeline arranged in parallel; along the flue gas flow direction, a steam boiler high-temperature flue gas shut-off valve and a steam boiler are sequentially arranged on the second high-temperature flue gas pipeline, and a TO furnace high-temperature flue gas shut-off valve and a TO furnace are sequentially arranged on the third high-temperature flue gas pipeline;

[0025] The high-temperature flue gas from the RTO combustion chamber directly enters the outlet mixing box through the first high-temperature flue gas pipeline. At the same time, by controlling the high-temperature flue gas cut-off valve of the steam boiler and / or the high-temperature flue gas cut-off valve of the TO furnace, it is controlled whether part of the high-temperature flue gas from the RTO combustion chamber enters the steam boiler and / or the TO furnace to achieve waste heat recovery and finally enters the outlet mixing box; during this period, the flow rate of the high-temperature flue gas is adjusted by controlling the steam boiler flue gas regulating valve and / or the TO furnace flue gas regulating valve;

[0026] Wherein, the temperature of the RTO combustion chamber is 760-1100°C, and the temperature of the outlet mixing box is 250-350°C.

[0027] As a preferred technical solution of the present invention, the pressure of the RTO combustion chamber is -500 to 500Pa, such as -500Pa, -300Pa, -100Pa, 0Pa, 100Pa, 200Pa, 400Pa or 500Pa, and the pressure of the outlet mixing box is -1500 to -500Pa, such as -1500Pa, -1300Pa, -1100Pa, -1000Pa, -800Pa, -600Pa or -500Pa, etc.;

[0028] The outlet flue gas temperature of the steam boiler is 150-500°C, for example, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C or 500°C, and preferably 200-400°C;

[0029] The outlet flue gas temperature of the TO furnace is 500-900°C, for example, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C or 900°C, and the pressure of the TO furnace is -1000Pa-0Pa, for example, -1000Pa, -900Pa, -800Pa, -600Pa, -500Pa, -300Pa, -100Pa or 0Pa, etc.

[0030] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0031] (1) The device for comprehensive utilization of waste heat of RTO process tail gas treatment of isophthalonitrile of the present invention is mainly characterized in that a waste heat utilization high-temperature flue gas pipeline with a waste heat utilization unit is arranged in parallel between the RTO combustion chamber and the outlet mixing box, and the opening and closing of the waste heat utilization unit is controlled by a waste heat utilization cut-off valve, so that waste heat recovery can be effectively realized, so that the heat of the isophthalonitrile process tail gas can be comprehensively utilized, fuel can be saved, and pollutant emissions can be reduced;

[0032] (2) The RTO waste heat comprehensive utilization device for treating tail gas from the isophthalonitrile process of the present invention comprises a waste heat utilization unit comprising a steam boiler and a TO furnace arranged in parallel, wherein the steam boiler is used to generate steam for reuse, and / or the TO furnace is used to reduce the fuel consumption of the TO furnace, so that the heat of the tail gas from the isophthalonitrile process is comprehensively utilized, while saving fuel and reducing the emission of pollutants. While being beneficial to the environment, it has obvious energy-saving and consumption-reducing effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process according to Example 1 of the present invention;

[0034] In the figure: 1-RTO combustion chamber; 2-steam boiler; 3-TO furnace; 4-export mixing box; 5-steam boiler high-temperature flue gas shut-off valve; 6-TO furnace high-temperature flue gas shut-off valve; 7-steam boiler flue gas regulating valve; 8-TO furnace flue gas regulating valve; 9-RTO high-temperature flue gas regulating valve. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0036] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0037] Example 1

[0038] This embodiment provides a device for comprehensive utilization of RTO waste heat from tail gas treatment in an isophthalonitrile process, such as Figure 1As shown, it comprises: an RTO combustion chamber 1 and an outlet mixing box 4, wherein a first high-temperature flue gas duct, a second high-temperature flue gas duct and a third high-temperature flue gas duct are arranged in parallel between the outlet of the RTO combustion chamber 1 and the inlet of the outlet mixing box 4;

[0039] Among them, along the flue gas flow direction, an RTO high-temperature flue gas regulating valve 9 is arranged on the first high-temperature flue gas pipeline, a steam boiler high-temperature flue gas shut-off valve 5 and a steam boiler 2 are arranged in sequence on the second high-temperature flue gas pipeline, and a TO furnace high-temperature flue gas shut-off valve 6 and a TO furnace 3 are arranged in sequence on the third high-temperature flue gas pipeline, that is, the waste heat utilization unit includes a steam boiler 2 and a TO furnace 3 arranged in parallel;

[0040] A steam boiler flue gas regulating valve 7 is provided on the second high-temperature flue gas pipeline between the steam boiler 2 and the outlet mixing box 4; a TO furnace flue gas regulating valve 8 is provided on the third high-temperature flue gas pipeline between the TO furnace 3 and the outlet mixing box 4;

[0041] Among them, the first high-temperature flue gas duct, the second high-temperature flue gas duct and the third high-temperature flue gas duct are independently circular ducts, and an insulation layer is provided inside the ducts; the steam boiler 2 is a waste heat steam fire tube boiler, and the TO furnace 3 is a direct-fired furnace.

[0042] Example 2

[0043] This embodiment provides an RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process. Compared with Embodiment 1, the only difference is that the second high-temperature flue gas duct and the steam boiler high-temperature flue gas shut-off valve 5, steam boiler 2, and steam boiler flue gas regulating valve 7 arranged thereon are completely omitted.

[0044] Example 3

[0045] This embodiment provides an RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process. Compared with Example 1, the only difference is that the third high-temperature flue gas duct and the TO furnace high-temperature flue gas shut-off valve 6, TO furnace 3, and TO furnace flue gas regulating valve 8 arranged thereon are completely omitted.

[0046] Comparative Example 1

[0047] This comparative example provides an RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process. Compared with Example 1, the only difference is that the second high-temperature flue gas duct and the steam boiler high-temperature flue gas shut-off valve 5, steam boiler 2, and steam boiler flue gas regulating valve 7 arranged thereon are completely omitted, and the third high-temperature flue gas duct and the TO furnace high-temperature flue gas shut-off valve 6, TO furnace 3, and TO furnace flue gas regulating valve 8 arranged thereon are completely omitted, that is, the high-temperature flue gas from the RTO combustion chamber 1 can only enter the outlet mixing box 4 through the first high-temperature flue gas duct with the RTO high-temperature flue gas regulating valve 9, and the RTO waste heat cannot be comprehensively utilized.

[0048] Application Example 1

[0049] This application example provides a method for using the isophthalonitrile process tail gas treatment RTO waste heat comprehensive utilization device described in Example 1, and the method includes the following contents:

[0050] The high-temperature flue gas from the RTO combustion chamber 1 directly enters the outlet mixing box 4 through the first high-temperature flue gas pipeline. At the same time, by controlling the steam boiler high-temperature flue gas cut-off valve 5 and / or the TO furnace high-temperature flue gas cut-off valve 6, it is controlled whether part of the high-temperature flue gas from the RTO combustion chamber 1 enters the steam boiler 2 and / or the TO furnace 3 to achieve waste heat recovery and finally enters the outlet mixing box 4; during this period, the flow rate of the high-temperature flue gas is adjusted by controlling the steam boiler flue gas regulating valve 7 and / or the TO furnace flue gas regulating valve 8;

[0051] Among them, the RTO combustion chamber 1 is in normal operation, the temperature of the RTO combustion chamber 1 is 980°C, and the temperature of the outlet mixing box 4 is 300°C; the pressure of the RTO combustion chamber is -100Pa, and the pressure of the outlet mixing box is -1500Pa;

[0052] After the electrical instrumentation system, water replenishment and steam system preparation of the steam boiler 2 are completed, the steam boiler 2 is ready for flue gas intake. The steam boiler high-temperature flue gas cut-off valve 5 is opened, and the steam boiler flue gas regulating valve 7 is opened to introduce the high-temperature flue gas from the RTO combustion chamber 1 into the steam boiler 2. The flue gas flux is adjusted by adjusting the opening of the steam boiler flue gas regulating valve 7. The boiler drum pressure of the steam boiler 2 is adjusted by the boiler outlet steam valve. The outlet flue gas temperature of the steam boiler is controlled to be 240°C.

[0053] After the electrical, instrumentation systems and feed system preparations of the TO furnace 3 are completed, and the TO furnace 3 is ready for flue gas inlet, the TO furnace flue gas regulating valve 8 is first opened to maintain the pressure in the TO furnace at -100Pa, and the TO furnace high-temperature flue gas cut-off valve 6 is opened to introduce high-temperature flue gas from the RTO combustion chamber. The flue gas flux is adjusted by adjusting the opening of the TO furnace flue gas regulating valve 8; the outlet flue gas temperature of the TO furnace is controlled to be 700°C; the TO furnace 3 first opens the TO furnace flue gas regulating valve 8, and then opens the TO furnace high-temperature flue gas cut-off valve 6, because the TO furnace should be operated in a state of slight negative pressure. In contrast, there is no order in which the two valves before and after the steam boiler 2 are opened;

[0054] In actual use, the steam boiler 2 and the TO furnace 3 are independent of each other and can be used in any order. They can be used separately or simultaneously.

[0055] In summary, the device for comprehensive utilization of waste heat of RTO waste gas treatment of isophthalonitrile process tail gas of the present invention is mainly to set a waste heat utilization high-temperature flue gas pipeline with a waste heat utilization unit in parallel between the RTO combustion chamber and the outlet mixing box, and control the opening and closing of the waste heat utilization unit by a waste heat utilization cut-off valve, so as to effectively realize waste heat recovery, so that the heat of the isophthalonitrile process tail gas can be comprehensively utilized, fuel can be saved, and pollutant emissions can be reduced.

[0056] Specifically, the RTO waste heat comprehensive utilization device for treating tail gas of isophthalonitrile process of the present invention comprises a steam boiler and a TO furnace arranged in parallel, and the steam boiler is used to generate steam for reuse, and / or the TO furnace is used to reduce the fuel consumption of the TO furnace, so that the heat of the tail gas of isophthalonitrile process is comprehensively utilized, while saving fuel and reducing the emission of pollutants, which is beneficial to environmental protection and has obvious energy-saving and consumption-reducing effects; in actual operation tests, the steam boiler and / or the TO furnace are used for waste heat recovery, and the surplus heat generated by the RTO treatment tail gas can be 100% recovered. If only the steam boiler is used to recover the waste heat, the RTO treatment of the tail gas of isophthalonitrile process with an air volume of 100,000 Nm3 / h can stably generate 3.5T / h of steam, that is, the heat of about 2.1 million kcal / h can be stably recovered; if only the TO furnace is used to utilize the waste heat, about 244Nm3 / h of natural gas can be saved.

[0057] The present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0058] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0059] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0060] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A device for comprehensive utilization of RTO waste heat from tail gas treatment in an isophthalonitrile process, characterized in that: include: An RTO combustion chamber and an outlet mixing box, wherein a first high-temperature flue gas duct and a waste heat utilization high-temperature flue gas duct are arranged in parallel between the outlet of the RTO combustion chamber and the inlet of the outlet mixing box; Among them, along the flue gas flow direction, a waste heat utilization shut-off valve and a waste heat utilization unit are sequentially arranged on the waste heat utilization high-temperature flue gas pipeline.

2. The RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process according to claim 1, characterized in that: The waste heat utilization high temperature flue gas pipeline includes a second high temperature flue gas pipeline and a third high temperature flue gas pipeline arranged in parallel; the waste heat utilization unit includes a steam boiler and a TO furnace; the waste heat utilization shut-off valve includes a steam boiler high temperature flue gas shut-off valve and a TO furnace high temperature flue gas shut-off valve; Along the flue gas flow direction, a steam boiler high-temperature flue gas shut-off valve and a steam boiler are sequentially arranged on the second high-temperature flue gas duct, and a TO furnace high-temperature flue gas shut-off valve and a TO furnace are sequentially arranged on the third high-temperature flue gas duct.

3. The RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process according to claim 2, characterized in that: A steam boiler flue gas regulating valve is arranged on the second high-temperature flue gas pipeline between the steam boiler and the outlet mixing box.

4. The RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process according to claim 2, characterized in that: A TO furnace flue gas regulating valve is arranged on the third high-temperature flue gas duct between the TO furnace and the outlet mixing box.

5. The RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process according to claim 1 or 2, characterized in that: The first high-temperature flue gas duct is a circular duct or a square duct, and an insulation layer is provided inside the duct.

6. The RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process according to claim 2, characterized in that: The second high-temperature flue gas duct and the third high-temperature flue gas duct are respectively and independently circular ducts or square ducts, and a heat-insulating layer is provided inside the ducts.

7. The RTO waste heat comprehensive utilization device for tail gas treatment of isophthalonitrile process according to claim 2, characterized in that: The steam boiler is a waste heat steam fire tube boiler, and the TO furnace is a direct-fired furnace.

8. A method for using the RTO waste heat comprehensive utilization device for treating tail gas from an isophthalonitrile process according to any one of claims 1 to 7, characterized in that: The method includes the following contents: The high-temperature flue gas from the RTO combustion chamber directly enters the outlet mixing box through the first high-temperature flue gas pipeline. At the same time, by controlling the opening and closing of the waste heat utilization cut-off valve, it is controlled whether part of the high-temperature flue gas from the RTO combustion chamber enters the waste heat utilization unit through the waste heat utilization high-temperature flue gas pipeline to achieve waste heat recovery, and finally enters the outlet mixing box; Wherein, the temperature of the RTO combustion chamber is 760-1100°C, and the temperature of the outlet mixing box is 250-350°C.

9. The method according to claim 8, characterized in that The waste heat utilization high-temperature flue gas pipeline comprises a second high-temperature flue gas pipeline and a third high-temperature flue gas pipeline arranged in parallel; along the flue gas flow direction, a steam boiler high-temperature flue gas shut-off valve and a steam boiler are sequentially arranged on the second high-temperature flue gas pipeline, and a TO furnace high-temperature flue gas shut-off valve and a TO furnace are sequentially arranged on the third high-temperature flue gas pipeline; The high-temperature flue gas from the RTO combustion chamber directly enters the outlet mixing box through the first high-temperature flue gas pipeline. At the same time, by controlling the high-temperature flue gas cut-off valve of the steam boiler and / or the high-temperature flue gas cut-off valve of the TO furnace, it is controlled whether part of the high-temperature flue gas from the RTO combustion chamber enters the steam boiler and / or the TO furnace to achieve waste heat recovery and finally enters the outlet mixing box; during this period, the flow rate of the high-temperature flue gas is adjusted by controlling the steam boiler flue gas regulating valve and / or the TO furnace flue gas regulating valve; Wherein, the temperature of the RTO combustion chamber is 760-1100°C, and the temperature of the outlet mixing box is 250-350°C.

10. The method according to claim 9, characterized in that The pressure of the RTO combustion chamber is -500~500Pa, and the pressure of the outlet mixing box is -1500~-500Pa; The outlet flue gas temperature of the steam boiler is 150-500°C; The outlet flue gas temperature of the TO furnace is 500-900° C., and the pressure of the TO furnace is -1000 Pa-0 Pa.

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