Balanced air duct cleaning system

Abstract

The present invention discloses a balanced air duct cleaning system, comprising a balanced air duct, wherein both ends of the balanced air duct are respectively connected to a secondary hot air duct, each secondary hot air duct is connected to an air preheater, and each air preheater is also respectively connected to a primary hot air duct and a flue, and is characterized in that an ash dispersing device for dispersing fly ash in the balanced air duct is provided at the bottom of the balanced air duct, and an ash blowing and cleaning device for blowing away fly ash on the inner wall of the balanced air duct is also provided in the balanced air duct. The balanced air duct cleaning system provided by the present invention is simple in design, convenient for modification, low in cost, and widely applicable. By setting up the system of the present invention, during the long-term operation stage of the boiler, it is ensured that the boiler can continue to operate safely under the condition that a single-side air preheater fails or suddenly stops, thereby improving the safety and reliability of the boiler equipment.

Description

Technical Field

[0001] The invention relates to a balanced air duct cleaning system, belonging to the technical field of balanced air duct structures of pulverized coal boilers. Background Art

[0002] For pulverized coal boilers with double-row air preheaters at the rear, a balancing air duct is generally set at the outlet of the hot secondary air duct of the air preheater to connect the hot air outlets of the air preheaters on both sides. When one side of the air preheater fails or is under maintenance, the secondary hot air can enter the secondary hot air duct on that side through the balancing air duct to ensure the normal operation of the boiler burner.

[0003] According to design experience and product research, on conventional pulverized coal furnace equipment, the balance air duct is generally arranged near the secondary hot air outlet of the air preheater, and holes are opened at the hot air outlet air ducts of the air preheaters on both sides and a connecting air duct is set. Due to the design based on the air duct, the ash removal and ash removal equipment is generally not considered.

[0004] Due to the structural characteristics of the rotary air preheater, the flue gas side is prone to conduct fly ash to the wind side. When the double-row air preheater is operating normally, there is generally no gas flow in the balanced air duct, but fly ash is easy to accumulate inside the balanced air duct. After a period of operation, fly ash accumulates, deposits or may block the balanced air duct. At this time, if one side of the air preheater fails or is suddenly closed, the balanced air duct will not be able to meet the ventilation needs, seriously affecting the safe operation and maintenance of the boiler. At the same time, during the design stage, the balanced air duct and its steel structure generally do not consider the possibility of ash accumulation in the balanced air duct. After long-term ash accumulation, the load on the balanced air duct increases, which may cause a safety accident of balanced air duct collapse. Summary of the invention

[0005] The technical problem to be solved by the present invention is: how to prevent the fly ash on the flue gas side from accumulating inside the balanced air duct.

[0006] In order to solve the above technical problems, the technical solution of the present invention is to provide a balanced air duct cleaning system, including a balanced air duct, wherein both ends of the balanced air duct are respectively connected to a secondary hot air duct, each secondary hot air duct is connected to an air preheater, and each air preheater is also respectively connected to a primary hot air duct and a flue gas duct, and is characterized in that an ash removal device for guiding fly ash in the balanced air duct is provided at the bottom of the balanced air duct, and an ash blowing and cleaning device for blowing away fly ash on the inner wall of the balanced air duct is also provided in the balanced air duct.

[0007] Preferably, the ash removal device comprises an ash removal pipeline, both ends of which are respectively connected to the bottom of the flue and the balance air duct; and an ash removal control valve is provided on the ash removal pipeline.

[0008] Preferably, at least one first hole is provided at the bottom of the balancing air duct, the first hole is connected to the flue through at least one ash removal pipe, and at least one ash removal control valve is provided on the ash removal pipe.

[0009] Preferably, one end of the ash removal pipe connected to the flue is arranged at the flue at the inlet of the air preheater.

[0010] Preferably, one end of the ash removal pipe connected to the flue is arranged at the flue at the outlet of the air preheater.

[0011] Preferably, the soot blowing and cleaning device comprises a purge air duct, both ends of which are respectively connected to the primary hot air duct and the balance air duct; and a purge control valve is provided on the purge air duct.

[0012] Preferably, the balancing air duct is provided with at least one second hole, and the second hole is connected to the primary hot air duct through at least one purge air duct; and the purge air duct is provided with at least one purge control valve.

[0013] Preferably, the connection position between the purge air duct and the balancing air duct is arranged at the top, side or bottom of the balancing air duct.

[0014] Preferably, the end of the purge air duct connected to the primary hot air duct is arranged at the primary hot air duct at the outlet of the air preheater.

[0015] The present invention uses the dust removal pipe and the purge air duct at the bottom of the balanced air duct to realize the dust removal and dust cleaning functions of the balanced air duct. Through the balanced air duct dust cleaning system of the present invention, the possibility of dust accumulation in the balanced air duct can be reduced, the risk of blockage and collapse of the balanced air duct can be reduced, and the safety and reliability of boiler operation can be improved.

[0016] The present invention makes relatively few design changes to the original conventional design of the balanced air duct, and can be adopted for newly built boilers or boilers in use. The balanced air duct cleaning system provided by the present invention is simple in design, convenient in modification, low in cost, and widely applicable. By setting up the system of the present invention, during the long-term operation stage of the boiler, the boiler can continue to operate safely under the condition that the single-side air preheater fails or suddenly stops, thereby improving the safety and reliability of the boiler equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a structural schematic diagram of a balanced air duct cleaning system. DETAILED DESCRIPTION

[0018] In order to make the present invention more clearly understood, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0019] Example 1

[0020] The present invention provides a balanced air duct cleaning system, such as Figure 1As shown, it includes an ash discharging pipe A1 and an ash discharging control valve 1, a purge air duct A2 and a purge control valve 2. The two ends of the balancing air duct 3 are respectively connected to the secondary hot air duct 7 connected to the outlet of the air preheater 4. One or more first holes are set at the bottom of the balancing air duct 3, and the air is introduced into the inlet flue 6 of the air preheater 4 through one or more ash discharging pipes A1. At the same time, at least one ash discharging control valve 1 is set on the ash discharging pipe A1. One or more second holes are set on the top, side or bottom of the balancing air duct 3, and the air is connected to the primary hot air duct 5 connected to the outlet of the air preheater 4 through one or more purge air ducts A2. At the same time, at least one purge control valve 2 is set on the purge air duct A2. When the boiler is in normal operation, the ash discharging pipe A1 and the purge air duct A2 are opened regularly to realize the ash cleaning and ash discharging functions of the balancing air duct 3.

[0021] In this embodiment, the dust removal duct A1 utilizes the pressure difference between the wind and smoke sides to achieve the dust removal function while avoiding the addition of equipment such as dust removal pumps; the purge air duct A2 utilizes primary hot air as the purge air to achieve dust cleaning while avoiding the addition of equipment such as soot blowers.

[0022] The system of the present invention is applicable not only to the balanced air duct 3 of the hot secondary air, but also to the balanced air ducts at other positions of the boiler.

[0023] Example 2

[0024] In this embodiment, the ash removal duct A1 at the bottom of the balanced air duct 3 can be introduced into any position of the outlet flue 6 of the air preheater 4 as required.

[0025] The rest is the same as Example 1.

Claims

1. A balanced air duct cleaning system, comprising a balanced air duct (3), wherein both ends of the balanced air duct (3) are respectively connected to a secondary hot air duct (7), each secondary hot air duct (7) is connected to an air preheater (4), and each air preheater (4) is also respectively connected to a primary hot air duct (5) and a flue (6), characterized in that: The bottom of the balancing air duct (3) is provided with an ash removal device for removing fly ash in the balancing air duct (3), and the balancing air duct (3) is also provided with an ash blowing and cleaning device for blowing away fly ash on the inner wall of the balancing air duct (3); The ash removal device comprises an ash removal pipeline (A1), the two ends of which are respectively connected to the bottom of the flue (6) and the balance air duct (3); an ash removal control valve (1) is provided on the ash removal pipeline (A1); The bottom of the balancing air duct (3) is provided with at least one first hole, the first hole is connected to the flue (6) through at least one ash removal pipe (A1), and the ash removal pipe (A1) is provided with at least one ash removal control valve (1); The soot blowing and cleaning device comprises a purge air duct (A2), the two ends of which are respectively connected to a primary hot air duct (5) and a balance air duct (3); a purge control valve (2) is provided on the purge air duct (A2); The balancing air duct (3) is provided with at least one second hole, and the second hole is connected to the primary hot air duct (5) through at least one purge air duct (A2); and the purge air duct (A2) is provided with at least one purge control valve (2).

2. A balanced air duct cleaning system as claimed in claim 1, characterized in that: The end of the ash removal pipe (A1) connected to the flue (6) is arranged at the flue (6) at the inlet of the air preheater (4).

3. A balanced air duct cleaning system as claimed in claim 1, characterized in that: The end of the ash removal pipe (A1) connected to the flue (6) is arranged at the flue (6) at the outlet of the air preheater (4).

4. A balanced air duct cleaning system as claimed in claim 1, characterized in that: The connection position between the purge air duct (A2) and the balancing air duct (3) is arranged at the top, side or bottom of the balancing air duct (3).

5. A balanced air duct cleaning system as claimed in claim 1, characterized in that: The end of the purge air duct (A2) connected to the primary hot air duct (5) is arranged at the primary hot air duct (5) at the outlet of the air preheater (4).

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