A deeply coordinated integrated denitrification system and method for oil and gas boilers

Abstract

The present invention discloses a deeply coordinated integrated denitrification system and method for oil and gas boilers. The system comprises: an ammonia injection grid fixedly mounted on a heating surface; a primary rectifier fixedly mounted inside a denitrification inlet flue; a denitrification reactor fixedly mounted on the inner wall of a diverting smoke chamber; a secondary rectifier fixedly mounted inside a diverting smoke chamber; and a tertiary rectifier fixedly mounted inside a diverting smoke chamber. The method comprises the following steps: flue gas generated by the oil and gas boiler is mixed with ammonia gas ejected from the ammonia injection grid to generate a mixed gas; a portion of the mixed gas passes through the primary rectifier, the denitrification reactor, the secondary rectifier, and the tertiary rectifier and is then discharged, while the other portion of the mixed gas enters a urea pyrolysis furnace through an induced draft fan; and ammonia gas generated after pyrolysis in the urea pyrolysis furnace enters the denitrification inlet flue.

Description

Technical Field

[0001] The present invention relates to the field of denitration technology, and in particular to a deeply coordinated integrated denitration system and method for oil and gas boilers. Background Art

[0002] like Figure 1 As shown, in the conventional design of the denitrification system for oil and gas boilers, due to the low temperature of the hot air, the heat source for urea pyrolysis to produce ammonia usually adopts the method of hot air from the boiler air preheater + electric heater and then sending it to the urea pyrolysis furnace; at the same time, the denitrification inlet flue 11 and the denitrification reactor 40 adopt an external pull-out arrangement, and a separate denitrification inlet flue 11 and denitrification reactor 40 are set. The flue gas undergoes multiple turns and a large number of guide vanes + rectifiers need to be arranged to evenly distribute the flue gas, which has high resistance and occupies a large area, and cannot meet market requirements.

[0003] Invention content

[0004] The purpose of the present invention is to provide a deeply coordinated integrated denitrification system and method for oil and gas boilers to solve the problems mentioned in the above background technology.

[0005] According to a first aspect of the present invention, a highly coordinated integrated denitration system for oil and gas boilers is provided, which is used in conjunction with an oil and gas boiler having a heating surface fixedly mounted therein and a denitration inlet flue and a deflecting flue chamber formed therein, comprising:

[0006] an ammonia injection grid, the ammonia injection grid being fixedly mounted on the heating surface, with its nozzle directed toward the deflection smoke chamber;

[0007] A primary rectifier, the primary rectifier being fixedly mounted inside the denitrification inlet flue and located between the ammonia injection grid and the diverting smoke chamber;

[0008] A denitration reactor, the denitration reactor being fixedly mounted on the inner wall of the diverting smoke chamber;

[0009] a secondary rectifier, the secondary rectifier being fixedly mounted inside the diverting smoke chamber and below the denitration reactor; and

[0010] A three-stage rectifying device is fixedly installed inside the deflecting smoke chamber and is located below the two-stage rectifying device.

[0011] Furthermore, it also includes a denitrification urea pyrolysis ammonia production system, which includes an induced draft fan and a urea pyrolysis furnace. The induced draft fan outlet pipe is fixedly installed on the inner wall of the turning smoke chamber and is located above the secondary rectifier. The urea pyrolysis furnace is fixedly installed on the frame outside the denitrification inlet flue. The inlet of the urea pyrolysis furnace is connected to the outlet of the induced draft fan, and the outlet of the urea pyrolysis furnace is connected to the inlet of the ammonia injection grid.

[0012] Furthermore, the denitrification inlet flue extends in a horizontal direction.

[0013] Furthermore, the ammonia injection grid is used to limit the transverse pitch of the heating surface.

[0014] Furthermore, the primary rectifying device is a boiler superheater, and the secondary rectifying device is an economizer.

[0015] According to a second aspect of the present invention, there is provided a method comprising the following steps:

[0016] The flue gas generated by the oil and gas boiler is mixed with the ammonia gas sprayed from the ammonia injection grid to generate a mixed gas;

[0017] A portion of the mixed gas passes through the primary rectifier, the denitration reactor, the secondary rectifier, and the tertiary rectifier in sequence and is discharged, and another portion of the mixed gas enters the urea pyrolysis furnace through the induced draft fan;

[0018] Ammonia generated after pyrolysis in the urea pyrolysis furnace enters the denitration inlet flue and mixes with the flue gas.

[0019] The present invention provides a highly synergistic, integrated denitration system and method for oil and gas boilers. The primary, secondary, and tertiary rectifiers improve gas flow field unevenness, reduce resistance, and enhance the fully disturbed mixing of the injected reducing agent ammonia with the flue gas, significantly reducing ammonia escape and improving denitration efficiency. Furthermore, the system utilizes a deeply coupled approach, reducing its footprint. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a structural diagram of the prior art;

[0022] Figure 2 Schematic diagram of the structure of the system of the present invention;

[0023] Figure 3 for Figure 2 A schematic diagram of the enlarged structure of the middle part A;

[0024] Figure 4 It is a schematic diagram of the process structure of the present invention.

[0025] In the figure: 10- oil and gas boiler, 11- denitrification inlet flue, 12- turning smoke chamber, 20- ammonia injection grid, 30- primary rectifier, 40- denitrification reactor, 50- secondary rectifier, 60- tertiary rectifier, 71- induced draft fan, 72- urea pyrolysis furnace. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0028] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0030] In the description of the embodiments of the present application, it should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, or the orientation or positional relationship commonly understood by those skilled in the art, or the orientation or positional relationship in which the product of the application is usually placed when in use. This is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0031] In the description of the embodiments of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0032] See also Figure 1-3 The present invention provides a highly coordinated, integrated denitration system for oil and gas boilers. The system includes an oil and gas boiler 10, with a fixed heating surface installed within. A denitration inlet flue 11 and a denitration chamber 12 are formed within the boiler. The aforementioned features are based on prior art, and the detailed structure is omitted here. The system also includes an ammonia injection grid 20, a primary rectifier 30, a denitration reactor 40, a secondary rectifier 50, and a tertiary rectifier 60.

[0033] The ammonia injection grid 20 is fixedly installed on the heating surface, and the nozzle direction is toward the smoke chamber 12;

[0034] The primary rectifying device 30 is fixedly installed inside the denitrification inlet flue 11 and is located between the ammonia injection grid 20 and the turning smoke chamber 12 .

[0035] The denitration reactor 40 is fixedly mounted on the inner wall of the diverting smoke chamber 12 .

[0036] The secondary rectifying device 50 is fixedly installed inside the deflecting smoke chamber 12 and is located below the denitration reactor 40 .

[0037] The third-stage rectifying device 60 is fixedly installed inside the deflecting smoke chamber 12 and is located below the second-stage rectifying device 50 .

[0038] The specific operation process is as follows: the flue gas generated when the oil and gas boiler 10 is started enters the denitrification inlet flue 11, and the ammonia injection grid 20 is started at the same time. The ammonia gas sprayed from the nozzle of the ammonia injection grid 20 is mixed with the flue gas in the denitrification inlet flue 11 to generate a mixed gas. Part of the mixed gas passes through the primary rectifier 30, the denitrification reactor 40, the secondary rectifier 50 and the tertiary rectifier 60 in sequence and is then discharged. The multi-stage rectifier can improve the uneven flow field, enhance the sufficient disturbance mixing of the injected reducing agent ammonia and the flue gas, greatly reduce the amount of ammonia escape, and improve the denitrification efficiency. In addition, this system adopts a deep coupling combination method to reduce the system's footprint.

[0039] In one embodiment, a denitrification urea pyrolysis ammonia production system is also included, comprising an induced draft fan 71 and a urea pyrolysis furnace 72. The induced draft fan 71 outlet duct is fixedly mounted on the inner wall of the deflection smoke chamber 12, above the secondary rectifier 50. The urea pyrolysis furnace 72 is fixedly mounted on a frame outside the denitrification inlet flue 11. The inlet of the urea pyrolysis furnace 72 communicates with the outlet of the induced draft fan 71, and the outlet of the urea pyrolysis furnace 72 communicates with the inlet of the ammonia injection grid 20.

[0040] Another part of the mixed gas enters the urea pyrolysis furnace 72 under the action of the induced draft fan 71. This part of the mixed gas brings a certain high temperature to the urea pyrolysis furnace 72. The ammonia generated after the pyrolysis of the urea pyrolysis furnace 72 enters the denitrification inlet flue 11 and mixes with the flue gas, ensuring the continuous and stable operation of the pyrolysis furnace 72 when the boiler changes operating conditions, reducing the temperature gradient of the ammonia injection grid 20, solving the problem of insufficient reaction of urea in the urea pyrolysis furnace 72, improving the operating reliability of the urea pyrolysis furnace 72 system, eliminating the traditional electric heater heating, reducing heat loss, and achieving excellent energy-saving effects.

[0041] In one embodiment, the denitrification inlet flue 11 extends in a horizontal direction to reduce the deflection of the flue gas and improve the uniform flow effect of the flue gas.

[0042] In one embodiment, the ammonia injection grid 20 is used to limit the transverse pitch of the heating surface. The design is optimized, and the primary rectifier 30 is used as a turbulent to enhance the sufficient disturbance and mixing of the injected reducing agent ammonia and the flue gas, thereby improving the denitrification efficiency.

[0043] In one embodiment, the primary rectifying device 30 is a boiler superheater, and the secondary rectifying device 50 is an economizer.

[0044] The present invention customizes the integrated design of the oil and gas boiler 10 and the denitrification area according to the design input conditions, adopts a deep coupling combination method, and carries out a one-furnace-one-scheme design of the oil and gas boiler 10 in coordination with the denitrification according to the specific requirements of the project. Construct a multifunctional use of the heating surface and denitrification system of the oil and gas boiler 10 with multiple integrated designs. Achieve high denitrification performance (high denitrification efficiency, low ammonia escape, and excellent process uniformity), enhance heat transfer on the rear heating surface of the oil and gas boiler 10, avoid problems such as blockage, corrosion, and wear; can effectively reduce the system resistance of the traditional oil and gas boiler 10 + denitrification method, and reduce land occupation and equipment investment.

[0045] One method, see Figure 4 , including the following steps:

[0046] S10 , the flue gas generated during operation of the oil and gas boiler 10 enters the denitrification inlet flue 11 and mixes with the ammonia gas sprayed from the ammonia spray grid 20 to generate a mixed gas.

[0047] S20: A portion of the mixed gas passes through the primary rectifier 30, the denitrification reactor 40, the secondary rectifier 50, and the tertiary rectifier 60 in sequence before being discharged. The multi-stage rectifier can improve the uneven flow field and enhance the sufficient disturbance mixing of the injected reducing agent ammonia and the flue gas, significantly reducing the amount of ammonia escape and improving the denitrification efficiency. The other portion of the mixed gas enters the urea pyrolysis furnace 72 through the induced draft fan 71;

[0048] S30. Ammonia generated after pyrolysis of the urea pyrolysis furnace 72 enters the denitrification inlet flue 11 and mixes with the flue gas, ensuring the continuous and stable operation of the pyrolysis furnace 72 when the boiler changes operating conditions, reducing the temperature gradient of the ammonia injection grid 20, solving the problem of insufficient reaction of urea in the urea pyrolysis furnace 72, improving the operating reliability of the urea pyrolysis furnace 72 system, eliminating the traditional electric heater heating, reducing heat loss, and achieving excellent energy-saving effect.

[0049] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A highly coordinated integrated denitration system for oil and gas boilers, used in conjunction with an oil and gas boiler having a heating surface fixedly mounted therein and a denitration inlet flue and a deflecting flue chamber formed therein, characterized in that: include: an ammonia injection grid, wherein the ammonia injection grid is fixedly mounted on the heating surface, with the nozzle direction facing the turning smoke chamber; A primary rectifying device, the primary rectifying device is fixedly installed inside the denitrification inlet flue and is located between the ammonia injection grid and the turning smoke chamber; A denitration reactor, the denitration reactor being fixedly mounted on the inner wall of the diverting smoke chamber; a secondary rectifier, the secondary rectifier being fixedly mounted inside the diverting smoke chamber and below the denitrification reactor; as well as A three-stage rectifying device, the three-stage rectifying device is fixedly installed inside the diverting smoke chamber and is located below the two-stage rectifying device; A denitrification urea pyrolysis ammonia production system, comprising an induced draft fan and a urea pyrolysis furnace, wherein the induced draft fan outlet pipe is fixedly mounted on the inner wall of the diverting smoke chamber and is located above the secondary rectifier; the urea pyrolysis furnace is fixedly mounted on a frame outside the denitrification inlet flue; the inlet of the urea pyrolysis furnace is connected to the outlet of the induced draft fan, and the outlet of the urea pyrolysis furnace is connected to the inlet of the ammonia injection grid; The flue gas generated by the oil and gas boiler is mixed with the ammonia gas sprayed from the ammonia injection grid to generate a mixed gas; A portion of the mixed gas passes through the primary rectifier, the denitration reactor, the secondary rectifier, and the tertiary rectifier in sequence and is discharged, and another portion of the mixed gas enters the urea pyrolysis furnace through the induced draft fan; Ammonia generated after pyrolysis in the urea pyrolysis furnace enters the denitration inlet flue and mixes with the flue gas; The primary rectifying device is a boiler superheater, and the secondary rectifying device is an economizer.

2. The deeply coordinated integrated denitrification system for oil and gas boilers according to claim 1 is characterized by: The denitrification inlet flue extends in a horizontal direction.

3. The deeply coordinated integrated denitrification system for oil and gas boilers according to claim 1 is characterized by: The ammonia injection grid is used to limit the transverse pitch of the heating surface.

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