Full-load denitration bypass flue system

Abstract

The utility model discloses a full-load denitration bypass flue system which comprises a bypass flue, the two ends of the bypass flue are communicated with the smoke output end of a pulverized coal boiler and the smoke input end of an SCR device respectively, and a first smoke flow adjusting device is arranged on the bypass flue. A second flue gas flow adjusting device is arranged on the main flue between the flue gas output end of the pulverized coal boiler and the flue gas input end of the SCR device, a temperature sensor is arranged at the flue gas input end of the SCR device, and the first flue gas flow adjusting device, the second flue gas flow adjusting device and the temperature sensor are all electrically connected with the control system. According to the utility model, when the boiler runs at a low load, the bypass flue can directly lead out part of high-temperature flue gas at the flue gas output end of the pulverized coal boiler to the flue gas input end of the SCR device, so that the temperature of the flue gas entering the SCR device is increased, and the SCR device works in an optimal reaction temperature interval.

Description

Technical Field

[0001] The utility model belongs to the technical field of boiler denitration, and in particular relates to a full-load denitration bypass flue system. Background Art

[0002] The 100MW~360MW class pulverized coal boilers all use selective catalytic reduction denitrification technology (SCR technology for short) to denitrify the boilers. The optimal reaction temperature of the SCR device is between 300 and 400°C. However, the boiler is in a low-load state when it is put into operation, and the inlet flue gas temperature of the SCR device is often lower than 300°C, making the nitrogen oxides emitted by the SCR device unable to meet national environmental protection requirements. Utility Model Content

[0003] In order to overcome the defects of the prior art, the utility model provides a full-load denitration bypass flue system, which can enable the SCR device to operate in an optimal reaction temperature range during the operation of the boiler.

[0004] The purpose of the utility model is achieved through the following technical solutions:

[0005] A full-load denitration bypass flue system, which is arranged on the main flue between the pulverized coal boiler and the SCR device, comprises:

[0006] A bypass flue, the two ends of which are respectively connected to the flue gas output end of the pulverized coal boiler and the flue gas input end of the SCR device;

[0007] A first smoke flow regulating device, the first smoke flow regulating device is arranged on the bypass flue;

[0008] A second flue gas flow regulating device, which is arranged on the main flue between the flue gas output end of the pulverized coal boiler and the flue gas input end of the SCR device;

[0009] A temperature sensor, which is arranged at the flue gas input end of the SCR device;

[0010] A control system is electrically connected to the first smoke flow regulating device, the second smoke flow regulating device and the temperature sensor.

[0011] In one embodiment, the first smoke flow regulating device includes a first electric regulating baffle electrically connected to the control system.

[0012] The beneficial effect of adopting the above technical solution is that the first electric adjustable baffle can adjust the flue gas flow entering the bypass flue by adjusting the opening.

[0013] In one embodiment, the first smoke flow regulating device comprises an electric closing damper electrically connected to the control system.

[0014] The beneficial effect of adopting the above technical solution is that the electric closing damper can completely close the bypass flue to prevent the high-temperature flue gas at the flue gas output end of the pulverized coal boiler from directly entering the SCR device when the flue gas temperature of the SCR device is higher than the optimal reaction temperature, thereby facilitating temperature control.

[0015] In one embodiment, the second smoke flow regulating device includes a second electric regulating baffle electrically connected to the control system.

[0016] The beneficial effect of adopting the above technical solution is that the second electric adjustable damper can adjust the flue gas flow entering the SCR device from the main flue by adjusting the opening, so as to reduce the flue gas flow entering the SCR device from the main flue when the flue gas temperature of the SCR device is lower than the optimal reaction temperature, thereby increasing the high-temperature flue gas entering the SCR device from the bypass flue, which is beneficial to temperature control.

[0017] In one embodiment, the bypass flue includes a main pipe and several branch pipes connected to the main pipe, the end of the main pipe away from the branch pipe is connected to the flue gas output end of the pulverized coal boiler, and the end of the branch pipe away from the main pipe is connected to the flue gas input end of the SCR device.

[0018] In one embodiment, a non-metallic expansion joint is provided on the main pipe.

[0019] The beneficial effects of adopting the above technical solution are: the non-metallic expansion joint is used to absorb the expansion of the boiler heating surface in three directions: downward, to the sides and to the rear of the furnace, so as to ensure that the main flue and the heating surface of the wall are not torn.

[0020] In one embodiment, a metal expansion joint is provided on the branch pipe.

[0021] The beneficial effect of adopting the above technical solution is that the metal expansion joint is used to absorb the expansion of the branch pipe itself and the expansion of the main flue in two directions to ensure that the branch pipe and the main flue are not torn.

[0022] In one embodiment, an economizer is provided on the main flue between the flue gas output end of the pulverized coal boiler and the flue gas input end of the SCR device, and the second flue gas flow regulating device is provided at the output end of the economizer.

[0023] In one embodiment, the control system is a DCS control system.

[0024] In one embodiment, the bypass flue is a stainless steel flue.

[0025] The beneficial effect of adopting the above technical solution is that the bypass flue is set as a stainless steel flue to adapt to the high temperature of the exhaust flue gas.

[0026] The beneficial effects of the utility model are:

[0027] When the boiler is running at a low load, the bypass flue can directly lead part of the high-temperature flue gas from the flue gas output end of the pulverized coal boiler to the flue gas input end of the SCR device, so as to increase the temperature of the flue gas entering the SCR device, thereby making the SCR device operate in an optimal reaction temperature range; in addition, the temperature sensor can detect the flue gas temperature at the flue gas input end of the SCR device, so as to facilitate the adjustment of the flow rate of the flue gas led out from the bypass flue through the first flue gas flow regulating device and the second flue gas flow regulating device, so that the flue gas temperature of the SCR device is always in the optimal reaction temperature range, which is beneficial for the SCR device to operate in the optimal reaction temperature range, thereby making the SCR device meet environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings.

[0029] in:

[0030] Figure 1 A schematic structural diagram of an embodiment of the utility model is shown;

[0031] Figure 2 Shows Figure 1 A top view of

[0032] In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0033] Reference numerals:

[0034] 1- pulverized coal boiler, 2- first electric regulating damper, 3- electric closing damper, 4- non-metallic expansion joint, 5- main pipe, 6- branch pipe, 7- metal expansion joint, 8- SCR device, 9- main flue, 10- second electric regulating damper, 11- economizer. DETAILED DESCRIPTION

[0035] The utility model will be further described below in conjunction with the accompanying drawings.

[0036] The utility model provides a full-load denitrification bypass flue system, such as Figure 1 and Figure 2 As shown, it is arranged on the main flue 9 between the pulverized coal boiler 1 and the SCR device 8, and includes:

[0037] A bypass flue, the two ends of which are connected to the flue gas output end of the pulverized coal boiler 1 and the flue gas input end of the SCR device 8 respectively;

[0038] A first smoke flow regulating device, the first smoke flow regulating device is arranged on the bypass flue;

[0039] A second flue gas flow regulating device, which is arranged on the main flue 9 between the flue gas output end of the pulverized coal boiler 1 and the flue gas input end of the SCR device 8;

[0040] A temperature sensor, which is arranged at the flue gas input end of the SCR device 8;

[0041] A control system is electrically connected to the first smoke flow regulating device, the second smoke flow regulating device and the temperature sensor.

[0042] It can be understood that when the boiler is running at a low load, the bypass flue can directly lead part of the high-temperature flue gas at the flue gas output end of the pulverized coal boiler 1 to the flue gas input end of the SCR device 8, so that the flue gas temperature entering the SCR device 8 is increased to above 300°C, so that the SCR device 8 operates in the optimal reaction temperature range to meet the commissioning requirements of the SCR device 8; in addition, the temperature sensor can detect the flue gas temperature at the flue gas input end of the SCR device 8, so as to facilitate the first flue gas flow regulating device and the second flue gas flow regulating device to adjust the flow of the flue gas led out of the bypass flue, so that the flue gas temperature of the SCR device 8 is always in the optimal reaction temperature range, which is beneficial for the SCR device 8 to operate in the optimal reaction temperature range, and then the SCR device 8 meets the environmental protection requirements.

[0043] In one embodiment, the first smoke flow regulating device includes a first electric regulating baffle 2 electrically connected to the control system.

[0044] It can be understood that the first electric adjustable damper 2 can adjust the flue gas flow entering the bypass flue by adjusting the opening.

[0045] In one embodiment, the first smoke flow regulating device comprises an electric closing damper 3 electrically connected to the control system.

[0046] It is understandable that the electric closing damper 3 can completely close the bypass flue to prevent the high-temperature flue gas at the flue gas output end of the pulverized coal boiler 1 from directly entering the SCR device 8 when the flue gas temperature of the SCR device 8 is higher than the optimal reaction temperature, thereby facilitating temperature control.

[0047] In one embodiment, the second smoke flow regulating device includes a second electric regulating baffle 10 electrically connected to the control system.

[0048] It can be understood that the second electric adjustable baffle 10 can adjust the flue gas flow entering the SCR device 8 from the main flue 9 by adjusting the opening, so as to reduce the flue gas flow entering the SCR device 8 from the main flue 9 when the flue gas temperature of the SCR device 8 is lower than the optimal reaction temperature, thereby increasing the high-temperature flue gas entering the SCR device 8 from the bypass flue, which is beneficial to temperature control.

[0049] In one embodiment, the bypass flue includes a main pipe 5 and a plurality of branch pipes 6 connected to the main pipe 5 , wherein one end of the main pipe 5 away from the branch pipe 6 is connected to the flue gas output end of the pulverized coal boiler 1 , and one end of the branch pipe 6 away from the main pipe 5 is connected to the flue gas input end of the SCR device 8 .

[0050] It should be noted that the first electric adjustment baffle 2 and the electric closing baffle 3 are both arranged at an end of the main pipe 5 away from the branch pipe 6 .

[0051] In one embodiment, a non-metal expansion joint 4 is provided on the main pipe 5 .

[0052] It can be understood that the non-metallic expansion joint 4 is used to absorb the expansion of the boiler heating surface in three directions: downward, to the sides and to the rear of the furnace, so as to ensure that the main flue 9 and the heating surface of the wall are not torn.

[0053] In one embodiment, a metal expansion joint 7 is provided on the branch pipe 6 .

[0054] It can be understood that the metal expansion joint 7 is used to absorb the expansion of the branch pipe 6 itself and the expansion of the main flue 9 in two directions to ensure that the branch pipe 6 and the main flue 9 are not torn.

[0055] In one embodiment, an economizer 11 is provided on the main flue 9 between the flue gas output end of the pulverized coal boiler 1 and the flue gas input end of the SCR device 8 , and the second flue gas flow regulating device is provided at the output end of the economizer 11 .

[0056] In one embodiment, the control system is a DCS control system.

[0057] In one embodiment, the bypass flue is a stainless steel flue.

[0058] It can be understood that the bypass flue is configured as a stainless steel flue to accommodate the high temperature of the exhaust flue gas.

[0059] In addition, it should be noted that the CFD flow field simulation technology can accurately calculate the resistance of the main flue 9 and the bypass flue, and can also accurately determine the required flue gas volume of the bypass flue to meet the flue gas temperature requirement at the flue gas input end of the SCR device 8.

[0060] The working process of the utility model is:

[0061] When the pulverized coal boiler 1 is running at low load and the flue gas temperature at the flue gas input end of the SCR device 8 is lower than 300°C, the DCS control system gives instructions to automatically open the first electric adjustment damper 2 and the electric closing damper 3, and adjust the amount of flue gas entering the bypass flue through the opening of the first electric adjustment damper 2; if the flue gas temperature at the flue gas input end of the SCR device 8 is still lower than 300°C at this time, the second electric adjustment damper 10 can be closed to increase the flue gas flow entering the bypass flue, thereby adjusting the flue gas temperature at the flue gas input end of the SCR device 8;

[0062] When the pulverized coal boiler 1 is running at high load, the flue gas temperature at the flue gas input end of the SCR device 8 is higher than 400°C. The electrically closed damper 3 can isolate the high-temperature flue gas from entering the bypass flue, so that the bypass flue is shut down, thereby adjusting the flue gas temperature at the flue gas input end of the SCR device 8.

[0063] In the description of the present invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0064] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments, and other arrangements may be designed without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the features described in the various dependent claims and herein may be combined in a manner different from that described in the original claims. It may also be understood that the features described in conjunction with the individual embodiments may be used in other described embodiments.

Claims

1. A full-load denitration bypass flue system, arranged on a main flue (9) between a pulverized coal boiler (1) and an SCR device (8), characterized in that: include: A bypass flue, wherein two ends of the bypass flue are respectively connected to a flue gas output end of the pulverized coal boiler (1) and a flue gas input end of the SCR device (8); a first smoke flow regulating device, wherein the first smoke flow regulating device is arranged on the bypass flue; a second flue gas flow rate regulating device, the second flue gas flow rate regulating device being arranged on a main flue (9) between a flue gas output end of a pulverized coal boiler (1) and a flue gas input end of a SCR device (8); a temperature sensor, the temperature sensor being arranged at a flue gas input end of the SCR device (8); A control system, wherein the control system is electrically connected to the first smoke flow regulating device, the second smoke flow regulating device and the temperature sensor.

2. A full-load denitrification bypass flue system according to claim 1, characterized in that: The first smoke flow regulating device comprises a first electric regulating baffle (2) electrically connected to the control system.

3. A full-load denitrification bypass flue system according to claim 2, characterized in that: The first smoke flow regulating device comprises an electric closing damper (3) electrically connected to the control system.

4. A full-load denitrification bypass flue system according to claim 1, characterized in that: The second smoke flow regulating device comprises a second electric regulating baffle (10) electrically connected to the control system.

5. A full-load denitrification bypass flue system according to claim 1, characterized in that: The bypass flue comprises a main pipe (5) and a plurality of branch pipes (6) connected to the main pipe (5); one end of the main pipe (5) away from the branch pipe (6) is connected to a flue gas output end of a pulverized coal boiler (1); and one end of the branch pipe (6) away from the main pipe (5) is connected to a flue gas input end of an SCR device (8).

6. A full-load denitrification bypass flue system according to claim 5, characterized in that: The main pipe (5) is provided with a non-metal expansion joint (4).

7. A full-load denitrification bypass flue system according to claim 5, characterized in that: The branch pipe (6) is provided with a metal expansion joint (7).

8. A full-load denitrification bypass flue system according to claim 1, characterized in that: An economizer (11) is arranged on the main flue (9) between the flue gas output end of the pulverized coal boiler (1) and the flue gas input end of the SCR device (8), and the second flue gas flow rate regulating device is arranged at the output end of the economizer (11).

9. A full-load denitrification bypass flue system according to claim 1, characterized in that: The control system is a DCS control system.

10. A full-load denitrification bypass flue system according to claim 1, characterized in that: The bypass flue is a stainless steel flue.

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