Sealing system of flue gas recirculation shut-off valve of mechanical grate garbage incinerator

Abstract

The utility model relates to the technical field of flue gas recirculation of waste incineration boilers, in particular to a sealing system of a flue gas recirculation shut-off valve of a mechanical grate waste incinerator, which introduces secondary air through the sealing system of the flue gas recirculation shut-off valve. The problems of sealing and nozzle blocking prevention after flue gas recirculation shutdown can be solved, the effect of mutual standby of secondary air and recirculated flue gas can be achieved, the investment cost of a sealing fan and a sealing air heater is saved, free switching and flexible adjustment can be achieved according to the emission concentration of NOX (nitric oxide), the whole system is simple in structure, and operation is convenient. And the power consumption and the input cost can be effectively reduced, and an effective solution is provided for the mechanical grate garbage incinerator to inhibit the generation of nitrogen oxides.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas recirculation of garbage incineration boilers, in particular to a sealing system of a flue gas recirculation shut-off valve of a mechanical grate garbage incinerator. Background Art

[0002] Flue gas recirculation technology is a low-nitrogen combustion technology used in mechanical grate waste incinerators. Its general principle is to introduce clean flue gas from the outlet of the induced draft fan and return it to the front and rear arches of the incinerator, using clean flue gas to replace part of the secondary air to participate in waste combustion, and inhibiting the generation of nitrogen oxides by reducing the oxygen content in the furnace.

[0003] The activation and deactivation of this flue gas recirculation system depends on the combustion conditions within the incinerator. When the combustion conditions require the deactivation of the flue gas recirculation system, the shut-off valve of the recirculation pipe needs to be closed. However, when the shut-off valve is closed, there is a problem of flue gas from the furnace flowing back into the recirculation pipe, causing the recirculation pipe nozzle to be blocked. In addition, the backflow of flue gas from the furnace into the recirculation pipe will also cause condensation.

[0004] In order to solve the above two problems that occur when the flue gas recirculation system is deactivated, most of the existing technologies adopt the method of adding a sealed air system at the shut-off valve of the flue gas recirculation. This type of sealed air system mainly includes a sealed fan and a sealed air heater, so the operating power consumption is also high, which increases the operating cost.

[0005] Therefore, it is necessary to design a sealing system for the flue gas recirculation shut-off valve of a mechanical grate waste incinerator. By efficiently combining the sealing system of the flue gas recirculation shut-off valve with the secondary air system, it is possible to save investment and operating costs and solve the problems of blockage and condensation of the flue gas recirculation pipe nozzle. Summary of the Invention

[0006] The purpose of the utility model is to overcome the shortcomings of the existing technology and provide a sealing system for the flue gas recirculation shut-off valve of a mechanical grate waste incinerator. Through the efficient combined use of the sealing system of the flue gas recirculation shut-off valve and the secondary air system, it can not only save investment and operating costs, but also solve the problems of blockage and condensation water in the flue gas recirculation pipe nozzle.

[0007] In order to achieve the above-mentioned objectives, the utility model provides a sealing system for a flue gas recirculation shut-off valve of a mechanical grate garbage incinerator, the incinerator is connected to a bag dust collector through a horizontal flue, the bag dust collector is connected to an induced draft fan through a first flue gas exhaust pipe, the induced draft fan is connected to a chimney through a second flue gas exhaust pipe, the second flue gas exhaust pipe is connected to a manual shut-off valve 1 through a first flue gas recirculation pipe, the manual shut-off valve 1 is connected to a secondary fan through a second flue gas recirculation pipe, the secondary fan is connected to an electric shut-off valve 1 through a third flue gas recirculation pipe, the electric shut-off valve 1 is connected to the incinerator through a fourth flue gas recirculation pipe, the incinerator is connected to an electric shut-off valve 2 through a third air inlet pipe, the electric shut-off valve 2 is connected to the secondary fan through the second air inlet pipe, the secondary fan is connected to the first air inlet pipe, the second air inlet pipe is connected to the manual shut-off valve 2 through the fourth air inlet pipe, the manual shut-off valve 2 is connected to the third flue gas recirculation pipe through the fifth air inlet pipe, and the manual shut-off valve 2 is connected to the fourth flue gas recirculation pipe through the sixth air inlet pipe.

[0008] Compared with the existing technology, the utility model introduces secondary air through the flue gas recirculation shut-off valve sealing system, which can not only achieve the sealing and nozzle blocking problem after the flue gas recirculation is stopped, but also achieve the role of secondary air and recirculated flue gas as a backup for each other, saving the investment cost of the sealed fan and the sealed air heater, and can be used according to NO X The emission concentration of (nitrogen oxides) can be switched freely and flexibly adjusted. The overall system structure is simple, which can effectively reduce power consumption and investment costs, and provide an effective solution for mechanical grate waste incinerators to inhibit the generation of nitrogen oxides. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a system schematic diagram of the present utility model.

[0010] Description of Reference Numerals

[0011] Incinerator 1, bag filter 2, induced draft fan 3, chimney 4, flue gas recirculation fan 5, secondary fan 6, manual shut-off valve 1 7, electric shut-off valve 1 8, manual shut-off valve 2 9, electric shut-off valve 2 10, second flue gas recirculation pipe 11, first flue gas recirculation pipe 12, second flue gas recirculation pipe 13, third flue gas recirculation pipe 14, fourth flue gas recirculation pipe 15, fifth air inlet pipe 16, sixth air inlet pipe 17, fourth air inlet pipe 18, first air inlet pipe 19, second air inlet pipe 20, third air inlet pipe 21, horizontal flue 22, first flue gas exhaust pipe 23. DETAILED DESCRIPTION

[0012] The present invention will now be further described with reference to the accompanying drawings.

[0013] See also Figure 1The utility model provides a sealing system for a flue gas recirculation shut-off valve of a mechanical grate garbage incinerator. The incinerator 1 is connected to the bag dust collector 2 through a horizontal flue 22. The bag dust collector 2 is connected to the induced draft fan 3 through a first flue gas exhaust pipe 23. The induced draft fan 3 is connected to the chimney 4 through a second flue gas exhaust pipe 11. The second flue gas exhaust pipe 11 is connected to a manual shut-off valve 7 through a first flue gas recirculation pipe 12. The manual shut-off valve 7 is connected to a secondary fan 6 through a second flue gas recirculation pipe 13. The secondary fan 6 is connected to an electric shut-off valve 8 through a third flue gas recirculation pipe 14. Then, the electric shut-off valve 1 8 is connected to the incinerator 1 through the fourth flue gas recirculation pipe 15, the incinerator 1 is connected to the electric shut-off valve 2 10 through the third air inlet pipe 21, the electric shut-off valve 2 10 is connected to the secondary fan 6 through the second air inlet pipe 20, the secondary fan 6 is connected to the first air inlet pipe 19, the second air inlet pipe 20 is connected to the manual shut-off valve 2 9 through the fourth air inlet pipe 18, the manual shut-off valve 2 9 is connected to the third flue gas recirculation pipe 14 through the fifth air inlet pipe 16, and the manual shut-off valve 2 9 is connected to the fourth flue gas recirculation pipe 15 through the sixth air inlet pipe 17.

[0014] The working principle of this utility model is as follows:

[0015] When the flue gas recirculation of the mechanical grate waste incinerator is disabled, the electric shut-off valve 8 and the manual shut-off valve 7 need to be closed. At this time, the sealing system of the flue gas recirculation provided by the present invention can open the manual shut-off valve 29 to introduce the secondary air of the secondary fan 6 from the second air inlet pipe 20 to the fifth air inlet pipe 16 and the sixth air inlet pipe 17 before and after the closed electric shut-off valve 8. The secondary air enters the incinerator 1 through the second air inlet pipe 20, the sixth air inlet pipe 17 and the fourth flue gas recirculation pipe 15, which can prevent the flue gas of the incinerator 1 from flowing back into the fourth flue gas recirculation pipe 15, so as to avoid clogging the nozzle of the fourth flue gas recirculation pipe 15 and generating flue gas condensate.

[0016] Secondary air is introduced from the second air inlet pipe 20 and enters the incinerator 1 through the fourth air inlet pipe 18, manual shutoff valve 2 9, sixth air inlet pipe 17, and fourth flue gas recirculation pipe 15, providing a sealing air barrier for the pipeline downstream of the electric shutoff valve 1 8 (i.e., the fourth flue gas recirculation pipe 15). The secondary air then flows through the fifth air inlet pipe 16 to provide a sealing air barrier for the pipeline upstream of the electric shutoff valve 8 (i.e., the third flue gas recirculation pipe 14). Manual shutoff valve 2 9 serves as a connecting valve between the secondary air inlet pipe and the flue gas recirculation pipe. The opening and closing of manual shutoff valve 2 9 controls the sealing air flow for the electric flue gas recirculation shutoff valve 8.

[0017] In addition, the secondary air enters the incinerator 1 through the third air inlet pipe 21 and the fourth flue gas recirculation pipe 15 respectively. The secondary air passing through the fourth flue gas recirculation pipe 15 serves as the first layer of secondary air, and the secondary air passing through the third air inlet pipe 21 serves as the second layer of secondary air, which can realize the layered combustion of garbage in the incinerator 1 and improve the combustion efficiency of garbage.

[0018] The above are only preferred embodiments of the present invention and are intended to help understand the method and core concept of this application. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be pointed out that for those skilled in the art, certain improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

[0019] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They 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 orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0020] The utility model solves as a whole the problems of flue gas backflow and high energy consumption of the sealing system in the prior art in order to overcome the problem of flue gas recirculation occurring after the shutdown of the waste incinerator. Through the efficient combined use of the sealing system of the flue gas recirculation shut-off valve and the secondary air system, it can save investment and operating costs, and solve the problems of blockage of the flue gas recirculation pipe nozzle and condensation water. The overall system structure is simple, which can effectively reduce power consumption and investment costs, and provide an effective solution for suppressing the formation of nitrogen oxides in mechanical grate waste incinerators.

Claims

1. A sealing system for a flue gas recirculation shut-off valve of a mechanical grate waste incinerator, characterized in that: The incinerator (1) is connected to the bag filter (2) through a horizontal flue (22), the bag filter (2) is connected to the induced draft fan (3) through a first flue gas exhaust pipe (23), the induced draft fan (3) is connected to the chimney (4) through a second flue gas exhaust pipe (11), the second flue gas exhaust pipe (11) is connected to the manual shut-off valve (7) through a first flue gas recirculation pipe (12), the manual shut-off valve (7) is connected to the secondary fan (6) through a second flue gas recirculation pipe (13), the secondary fan (6) is connected to the electric shut-off valve (8) through a third flue gas recirculation pipe (14), the electric shut-off valve (8) is connected to the fourth flue gas recirculation pipe ( 15) is connected to the incinerator (1), the incinerator (1) is connected to the electric shut-off valve 2 (10) through the third air inlet pipe (21), the electric shut-off valve 2 (10) is connected to the secondary fan (6) through the second air inlet pipe (20), the secondary fan (6) is connected to the first air inlet pipe (19), the second air inlet pipe (20) is connected to the manual shut-off valve 2 (9) through the fourth air inlet pipe (18), the manual shut-off valve 2 (9) is connected to the third flue gas recirculation pipe (14) through the fifth air inlet pipe (16), and the manual shut-off valve 2 (9) is connected to the fourth flue gas recirculation pipe (15) through the sixth air inlet pipe (17).

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