Treatment method for preventing pipe explosion of boiler economizer

Abstract

The invention relates to a treatment method for preventing tube explosion of a boiler economizer, which belongs to the technical field of dry quenching boilers, and comprises the following steps of: additionally arranging anti-abrasion tiles on the windward sides of the ends of a first row of finned tubes and a second row of finned tubes, and spraying an anti-abrasion material on the windward sides of the first row of finned tubes, the second row of finned tubes and a third row of finned tubes to form an anti-abrasion coating; a flow guide pipe is arranged over the position between the first row of abraded finned tubes and the adjacent finned tubes in the same row, and the flow guide pipe is located between the first row of finned tubes and the second row of finned tubes. The invention solves the problem of frequent pipe explosion of the coal economizer of the dry quenching boiler, reduces the steam loss, avoids frequent shutdown and maintenance of the waste heat boiler, and avoids the use of water coke in the blast furnace.

Description

Technical Field

[0001] This invention belongs to the field of dry quenching coke boiler technology and relates to a method for preventing economizer tube rupture in boilers. Background Technology

[0002] The dry quenching boiler is a crucial component of the entire dry quenching process system. Its proper operation directly impacts the operation of the dry quenching unit and the recovery of waste heat from power generation. With the continuous development of dry quenching technology, significant improvements have been made to the system and equipment in areas such as reducing investment, lowering energy consumption, and increasing thermal efficiency, making the dry quenching system safer, more reliable, and more stable. The main function of the dry quenching boiler is to lower the temperature of the inert circulating gas in the dry quenching system and absorb heat to generate steam for the turbine generator, thus achieving energy savings.

[0003] The economizer of the dry-quenched coke boiler is located in the low-temperature zone at the bottom of the boiler, formed by the economizer wall panels. The economizer tube bundle is a spiral finned tube, consisting of 56 tubes wound upwards at an angle to form a staggered bundle, connected in the middle by pressed elbows. After the feedwater enters the economizer header, the flue gas flows upwards in the opposite direction, enters the economizer outlet header, and then enters the steam drum water space through connecting pipes. The economizer is a suspended structure, with the tube bundle suspended from the crossbeam by spiral finned tube clamps. The two ends of the crossbeam are fixed to the economizer wall panels, and the force is then transferred to the elevation platform through the economizer wall panels.

[0004] With the increase in the processing capacity of dry quenching units, the increased circulating air volume and boiler inlet suction lead to an increase in the internal velocity of the boiler body. This intensifies the wear of boiler pipes by coke powder in the flue gas circulation system, resulting in a shortened service life of the boiler pipes. Excessive flue gas velocity is a direct cause of severe economizer wear. The wear on the heated metal surface is directly proportional to the kinetic energy and the number of impacts of fly ash particles. The kinetic energy of fly ash particles is proportional to the square of their velocity, and the number of impacts is proportional to the first power of their velocity. Thus, the wear of the finned tubes is directly proportional to the cube of the flue gas velocity. Therefore, boiler tube rupture accidents are prone to occur in the economizer area.

[0005] A tube rupture in a dry quenching coke boiler is a major accident in production. The water and steam leaking from the ruptured tube enter the dry quenching furnace with the circulating gas and react with the red-hot coke to form a water-gas reaction, causing a sharp increase in the H2 and CO content in the circulating gas. If measures are not taken in time, a serious boiler explosion may occur. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for preventing economizer tube rupture in boilers, so as to solve the problem of frequent economizer tube rupture in dry quenching coke boilers.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for preventing boiler economizer tube rupture involves installing wear-resistant tiles on the windward side of the first and second rows of finned tubes, and spraying wear-resistant material onto the windward side of the first, second, and third rows of finned tubes to form a wear-resistant coating.

[0009] Optionally, when the first row of finned tubes is worn, a guide pipe is provided directly above the worn finned tube in the first row and its adjacent finned tube in the same row, and the guide pipe is located between the first row of finned tubes and the second row of finned tubes.

[0010] Optionally, the diameter of the guide tube is less than or equal to the diameter of the finned tube.

[0011] Optionally, the two ends of the guide tube are welded to the economizer crossbeam and the water-cooled wall, respectively.

[0012] Optionally, the width of the movable smoke baffle is increased so that the movable smoke baffle overlaps with the projection of the abrasion-resistant tile located below it in the horizontal plane.

[0013] Optionally, the overlap width is ≥40mm.

[0014] Optionally, the wear-resistant material is a nickel-based alloy.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. Solved the problem of frequent tube ruptures in the economizer of dry quenching coke boilers.

[0017] 2. Reduced steam loss. Taking a steel plant experiencing 5 economizer tube ruptures in a dry quenching coke boiler per year as an example, with an average shutdown time of 23 hours each time, and a boiler steam production capacity of 79 tons of steam / hour, and a cost of 90 yuan per ton of steam, the annual economic benefit after implementing this method is: 90 yuan * 79 tons / hour * 23 hours * 5 times = 817,650 yuan.

[0018] 3. It avoids frequent shutdowns for maintenance of waste heat boilers, as frequent boiler start-ups and shutdowns would significantly shorten the boiler's service life.

[0019] 4. It avoids the use of water coke in the blast furnace, which helps stabilize various process indicators of the blast furnace, extends the service life of the blast furnace, and is conducive to the long-term smooth operation of the blast furnace.

[0020] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of the method for preventing boiler economizer tube rupture according to the present invention.

[0023] Attached reference numerals: 1. Finned tube; 2. Wear-resistant tile; 3. Crossbeam; 4. Water-cooled wall; 5. Guide pipe; 6. Original movable smoke baffle; 7. Newly added smoke baffle; 8. Wear-resistant coating. Detailed Implementation

[0024] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0025] Please see Figure 1 A method for preventing boiler economizer tube rupture involves installing anti-wear tiles 2 on the windward side of the ends of the first and second rows of finned tubes, and spraying wear-resistant material on the windward side of the first, second, and third rows of finned tubes to form a wear-resistant coating 8. The wear-resistant material can be a nickel-based alloy.

[0026] When the first row of finned tubes is worn, a guide pipe 5 is installed directly above the worn finned tube in the first row and its adjacent finned tube in the same row, and the guide pipe 5 is located between the first row of finned tubes and the second row of finned tubes.

[0027] Optionally, the diameter of the guide tube 5 is less than or equal to the diameter of the finned tube 1; the two ends of the guide tube 5 are welded to the economizer crossbeam 3 and the water-cooled wall 4, respectively.

[0028] To prevent wear and leakage of the finned tube below the movable smoke baffle, the present invention modifies the movable smoke baffle by increasing its width so that the projection of the movable smoke baffle and the wear-resistant tile 2 located below it in the horizontal plane overlaps, preferably with an overlap width ≥ 40 mm.

[0029] Example

[0030] A method for preventing economizer tube rupture in boilers includes the following steps:

[0031] 1. Anti-wear tiles 2 are installed on the windward side of the first and second rows of finned tubes, ensuring that the airflow only wears the anti-wear tiles 2, thus protecting the economizer finned tubes 1. When solid fuels are burned in the boiler, the flue gas often carries a large amount of ash particles. When these ash particles flow through the convective heating surface finned tubes with the flue gas, their impact and cutting action cause wear. One function of the anti-wear tiles 2 is to prevent the protected economizer tube section from directly contacting the ash particles in the flue gas. Another function is to reduce the flue gas velocity in the gap between the economizer tube bend and the furnace wall, thereby reducing wear on the tube section at that location.

[0032] 2. Apply wear-resistant material to the windward side of the first, second, and third rows of finned tubes to form a wear-resistant coating. Nickel-based alloys are a class of metallic materials based on iron, nickel, cobalt, and copper, capable of long-term operation at temperatures above 600℃ and under certain stress. Nickel-based alloys possess high high-temperature strength, good oxidation and corrosion resistance, and excellent fatigue performance, fracture toughness, and wear resistance. Nickel-based alloys have a single austenitic structure, exhibiting good structural stability and reliability at various temperatures, thereby improving the corrosion resistance and wear resistance of the economizer finned tubes.

[0033] 3. Installing a guide pipe 5: Measure the diameter and spacing of the first row of finned tubes on the economizer's windward side. The standard design diameter of finned tube 1 is 45mm, and the standard design spacing is 105mm. If the measured finned tube diameter is ≤43mm, or the finned tube spacing is ≥112mm, add a guide pipe 5 with an outer diameter of 42mm and a thickness of 8mm 75mm above the center of the finned tubes where the data deviates. The two ends of the guide pipe 5 are welded to the crossbeam 3 and the water-cooled wall 4, respectively. This method protects the finned tubes that have been worn by dust erosion, as the guide pipe 5 reduces the direct impact of dust in the flue gas on the sides of the first row of worn finned tubes and the front of the corresponding finned tubes in the second row. Furthermore, the installation of the guide pipe is quick.

[0034] 4. Increase the width of the movable smoke baffle: A new smoke baffle 7 is added to the edge of the original movable smoke baffle 6 in the economizer, so that the projection of the movable smoke baffle 7 on the horizontal plane overlaps with that of the wear-resistant tile 2 located below it. The new smoke baffle 7 is sealed and welded to the original movable smoke baffle 6. The movable smoke baffles on the manhole and outlet sides of the economizer are installed unevenly in height and with inconsistent spacing. When flue gas flows through the economizer, dust enters the gaps between the movable smoke baffles and accelerates its flow, causing wear and leakage of the finned tubes below the movable smoke baffles. Increasing the width of the movable smoke baffle from 80mm to 150mm allows the projection of the movable smoke baffle on the horizontal plane to overlap with that of the wear-resistant tile 2 located below it, with an overlap width of 40mm, effectively preventing wear and leakage of the finned tubes below the movable smoke baffle.

[0035] Experiments have verified that after modifying the dry quenching coke boiler using this method, tube rupture no longer occurred, steam loss was reduced, frequent shutdowns of the waste heat boiler for maintenance were avoided, and the use of water coke in the blast furnace was prevented.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preventing economizer tube rupture in boilers, characterized in that: Wear-resistant tiles (2) are installed on the windward side of the first and second rows of finned tubes, and wear-resistant materials are sprayed on the windward side of the first, second and third rows of finned tubes to form a wear-resistant coating (8).

2. The method for preventing boiler economizer tube rupture according to claim 1, characterized in that: When the first row of finned tubes is worn, a guide pipe (5) is installed directly above the worn finned tube in the first row and its adjacent finned tube in the same row, and the guide pipe (5) is located between the first row of finned tubes and the second row of finned tubes.

3. The method for preventing boiler economizer tube rupture according to claim 2, characterized in that: The diameter of the guide tube (5) is less than or equal to the diameter of the finned tube (1).

4. The method for preventing boiler economizer tube rupture according to claim 2, characterized in that: The two ends of the guide pipe (5) are welded to the economizer beam (3) and the water-cooled wall (4) respectively.

5. The method for preventing boiler economizer tube rupture according to claim 1, characterized in that: Increase the width of the movable smoke baffle so that the movable smoke baffle overlaps with the projection of the abrasion-resistant tile (2) located below it in the horizontal plane.

6. The method for preventing boiler economizer tube rupture according to claim 5, characterized in that: Overlap width ≥ 40mm.

7. The method for preventing boiler economizer tube rupture according to claim 1, characterized in that: The wear-resistant material is a nickel-based alloy.

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