Flue gas guiding device for SCR (selective catalytic reduction) outlet flue of coal-fired boiler

Abstract

The utility model discloses a flue gas guiding device for an SCR (Selective Catalytic Reduction) outlet flue of a coal-fired boiler, which belongs to the technical field of boiler thermal engineering equipment and comprises an SCR denitration reactor, and an outlet of the SCR denitration reactor is arranged downwards and is connected with a fly ash collecting hopper; one side of the fly ash collecting hopper is connected with a flue communicated with the fly ash collecting hopper, an upper-stage air preheater and a guide plate are arranged in the flue, one end of the guide plate extends to an inlet of the upper-stage air preheater, and the other end of the guide plate extends to an outlet of the SCR denitration reactor. According to the utility model, the continuous guide plate is additionally arranged in the connecting flue from the outlet of the SCR denitration reactor to the inlet of the upper-stage air preheater, so that the effect of balancing the flue gas flow on the two sides of the upper-stage air preheater is achieved, and the problem of unbalanced flue gas flow velocity and heat exchange is solved. The fly ash collecting hopper is arranged to collect pulverized coal ash passing through an outlet of the SCR denitration reactor, so that the problem that a channel of the air preheater is blocked due to deposition of the pulverized coal ash is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of boiler thermal engineering equipment, in particular to a flue gas guide device for an SCR outlet flue of a coal-fired boiler. Background Art

[0002] Coal-fired boilers are important equipment in the field of industrial energy. Their working principle is to generate heat by burning coal powder, and heat water to generate steam for various industrial purposes. During the operation of coal-fired boilers, coal powder and oxygen undergo combustion reaction to generate high-temperature flue gas, which is discharged from the boiler with waste heat. In order to improve the utilization efficiency of the boiler, economizers and air preheaters are usually installed to use flue gas for heat exchange with water and air. After the flue gas is cooled by heat exchange, it is discharged after removing various harmful substances.

[0003] In the prior art, since most SCR denitrification reactors are installed on the basis of the original boiler shaft flue, the process in which the flue gas passes through the upper economizer to enter the SCR denitrification reactor and flows into the upper air preheater needs to go through multiple turning processes. Due to the effect of centrifugal force, a velocity difference between the inside and outside of the turning radius will be formed when the flue gas turns. After passing a bend, most of the flue gas will enter the next process from the outer bend, resulting in an unbalanced flue gas flow rate in the lower process, and then causing uneven heat exchange. The low-speed area will also cause fly ash deposition, blocking the air preheater channel, and ultimately causing problems such as increased boiler exhaust temperature, increased electrical consumption of the induced draft fan, and the inability of the boiler to operate at high load. Utility Model Content

[0004] In order to solve the above technical problems, the utility model proposes a flue gas guide device for the SCR outlet flue of a coal-fired boiler, which achieves the effect of balancing the flue gas flow on both sides of the upper air preheater by adding a continuous guide plate in the connecting flue from the outlet of the SCR denitration reactor to the inlet of the upper air preheater, so as to solve the problem of uneven flue gas flow rate and heat exchange. The utility model also collects the coal fly ash passing through the outlet of the SCR denitration reactor by setting a fly ash collection bucket, so as to solve the problem of fly ash deposition blocking the air preheater channel.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is:

[0006] A smoke guide device for an SCR outlet flue of a coal-fired boiler comprises an SCR denitration reactor, wherein the outlet of the SCR denitration reactor is arranged downward and is connected to a fly ash collecting hopper; one side of the fly ash collecting hopper is connected to a flue communicating therewith, wherein an upper air preheater and a guide plate are arranged in the flue, wherein one end of the guide plate extends to the inlet of the upper air preheater, and the other end extends to the outlet of the SCR denitration reactor.

[0007] Furthermore, the guide plate includes a first guide portion, a second guide portion and a third guide portion, one end of the first guide portion extends to the outlet of the SCR denitration reactor, and the other end is connected to one end of the second guide portion, the other end of the second guide portion is connected to one end of the third guide portion, and the other end of the third guide portion extends to the inlet of the upper air preheater.

[0008] Furthermore, the first guide portion and the third guide portion are both arranged perpendicularly to the second guide portion, and the second guide portion is arranged parallel to the outlet of the SCR denitration reactor and the inlet of the upper air preheater.

[0009] Further, the connection between the first guide portion and the second guide portion is transitioned through an arc, and the connection between the second guide portion and the third guide portion is transitioned through an arc.

[0010] Furthermore, the first guide portion divides the outlet of the SCR denitration reactor into two equal parts, and the third guide portion divides the inlet of the upper air preheater into two equal parts.

[0011] Furthermore, the upper air preheater is located obliquely below the SCR denitration reactor.

[0012] Furthermore, a lower-stage economizer is provided in the flue, and the lower-stage economizer is located below the upper-stage air preheater.

[0013] Furthermore, a lower-stage air preheater is provided in the flue, and the lower-stage air preheater is located below the lower-stage economizer, and an outlet of the lower-stage air preheater is communicated with an outlet of the flue.

[0014] Furthermore, the outlet of the flue is arranged upward.

[0015] Due to the adoption of the above technical solution, the utility model has the following beneficial effects:

[0016] The utility model sets a continuous guide plate between the outlet of the SCR denitration reactor and the inlet of the upper air preheater, which can effectively balance the flue gas flow and velocity of the upper air preheater, the lower economizer, and the lower air preheater, avoid the problem of unbalanced flue gas velocity and heat exchange, increase the flue gas velocity, avoid the ash accumulation and blockage of the air preheater and economizer caused by low flue gas velocity, and effectively extend the cleaning cycle of the boiler air preheater and economizer. Since the air preheater and economizer have less ash, their heat exchange efficiency can be effectively improved. In addition, by evenly diverting the flue gas, the problem of excessive flue gas velocity of the air preheater and economizer, flushing the economizer tube bundle and causing wear and leakage can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1This is a schematic diagram of the structure of a smoke guide device for the SCR outlet flue of a coal-fired boiler proposed by the utility model;

[0018] Among them, the markings in the attached figure are: 1-SCR denitrification reactor, 2-guide plate, 3-fly ash collection bucket, 4-upper air preheater, 5-lower economizer, 6-lower air preheater. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] Example

[0021] like Figure 1 -shown, a flue gas guide device for the SCR outlet flue of a coal-fired boiler comprises an SCR denitration reactor 1. The outlet of the SCR denitration reactor 1 is arranged downward and is connected to a fly ash collecting hopper 3. The fly ash collecting hopper 3 is used to collect coal fly ash to prevent the fly ash from being deposited and blocking the air preheater channel.

[0022] One side of the fly ash collecting hopper 3 is connected to a flue communicating therewith, in which an upper air preheater 4 and a guide plate 2 are arranged, one end of the guide plate 2 extends to the inlet of the upper air preheater 4, and the other end extends to the outlet of the SCR denitration reactor 1.

[0023] Specifically, the guide plate 2 includes a first guide part, a second guide part and a third guide part. One end of the first guide part extends to the outlet of the SCR denitration reactor 1, and the other end is connected to one end of the second guide part. The other end of the second guide part is connected to one end of the third guide part, and the other end of the third guide part extends to the inlet of the upper air preheater 4. The first guide part and the third guide part are both arranged vertically with the second guide part, and the second guide part is arranged parallel to the outlet of the SCR denitration reactor 1 and the inlet of the upper air preheater 4. The connection between the first guide part and the second guide part is transitioned by an arc, and the connection between the second guide part and the third guide part is transitioned by an arc. The arc setting is conducive to the diversion of flue gas. The first guide part divides the outlet of the SCR denitration reactor 1 into two equal parts, and the third guide part divides the inlet of the upper air preheater 4 into two equal parts. In this way, the flue gas at the outlet of the SCR denitration reactor 1 is divided into two equal parts and passes through the front and rear sides of the upper air preheater 4 respectively.

[0024] The upper air preheater 4 is located obliquely below the SCR denitration reactor 1. A lower economizer 5 is provided in the flue, and the lower economizer 5 is located below the upper air preheater 4. A lower air preheater 6 is provided in the flue, and the lower air preheater 6 is located below the lower economizer 5, and the outlet of the lower air preheater 6 is connected to the outlet of the flue. The outlet of the flue is arranged upward.

[0025] The utility model sets a continuous guide plate 2 between the outlet of the SCR denitration reactor 1 and the inlet of the upper air preheater 4, which can effectively balance the flue gas flow and velocity on both sides of the upper air preheater 4, the lower economizer 5, and the lower air preheater 6, avoid the problem of unbalanced flue gas flow velocity and heat exchange, increase the flue gas flow velocity, avoid the ash accumulation and blockage of the air preheater and economizer caused by low flue gas flow velocity, and effectively extend the cleaning cycle of the boiler air preheater and economizer. Since the air preheater and economizer have less ash, their heat exchange efficiency can be effectively improved. In addition, by evenly diverting the flue gas, the problem of excessive flue gas flow velocity of the air preheater and economizer, flushing the economizer tube bundle and causing wear and leakage can be avoided.

[0026] The above description is a detailed description of the preferred feasible embodiment of the utility model, but the embodiment is not used to limit the scope of the patent application of the utility model. All equivalent changes or modified changes completed under the technical spirit suggested by the utility model should fall within the patent scope covered by the utility model.

Claims

1. A flue gas guide device for an SCR outlet flue of a coal-fired boiler, comprising an SCR denitration reactor, characterized in that: The outlet of the SCR denitration reactor is arranged downward and is connected to a fly ash collecting hopper; one side of the fly ash collecting hopper is connected to a flue communicating therewith, and an upper air preheater and a guide plate are arranged in the flue, one end of the guide plate extends to the inlet of the upper air preheater, and the other end extends to the outlet of the SCR denitration reactor.

2. A smoke guide device for an SCR outlet flue of a coal-fired boiler according to claim 1, characterized in that: The guide plate includes a first guide portion, a second guide portion and a third guide portion, one end of the first guide portion extends to the outlet of the SCR denitration reactor, and the other end is connected to one end of the second guide portion, the other end of the second guide portion is connected to one end of the third guide portion, and the other end of the third guide portion extends to the inlet of the upper air preheater.

3. A smoke guide device for the SCR outlet flue of a coal-fired boiler according to claim 2, characterized in that: The first guide portion and the third guide portion are both arranged perpendicularly to the second guide portion, and the second guide portion is arranged parallel to the outlet of the SCR denitration reactor and the inlet of the upper air preheater.

4. A smoke guide device for an SCR outlet flue of a coal-fired boiler according to claim 3, characterized in that: The connection between the first guide portion and the second guide portion is transitioned through an arc, and the connection between the second guide portion and the third guide portion is transitioned through an arc.

5. A smoke guide device for an SCR outlet flue of a coal-fired boiler according to claim 4, characterized in that: The first guide portion divides the outlet of the SCR denitration reactor into two equal parts, and the third guide portion divides the inlet of the upper air preheater into two equal parts.

6. The smoke guide device for the SCR outlet flue of a coal-fired boiler according to claim 1, characterized in that: The upper air preheater is located obliquely below the SCR denitration reactor.

7. A smoke guide device for an SCR outlet flue of a coal-fired boiler according to claim 6, characterized in that: A lower-stage economizer is arranged in the flue, and the lower-stage economizer is located below the upper-stage air preheater.

8. The smoke guide device for the SCR outlet flue of a coal-fired boiler according to claim 7, characterized in that: A lower-stage air preheater is arranged in the flue, and the lower-stage air preheater is located below the lower-stage economizer. The outlet of the lower-stage air preheater is communicated with the outlet of the flue.

9. A smoke guide device for an SCR outlet flue of a coal-fired boiler according to claim 8, characterized in that: The outlet of the flue is arranged upward.

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