A high-temperature corrosion and coking resistant boiler furnace water wall structure

Abstract

The application discloses a kind of water-cooled wall structure of anti-high temperature corrosion and anti-coking boiler furnace in the technical field of boiler processing, including water circulation compression circulating unit, acoustic soot blower and water-cooled pipe group, and compression circulating unit is communicated with water-cooled pipe group to form closed cooling water circulation loop;Water-cooled pipe group contains multiple vertical water-cooled pipes that are uniformly arranged along the longitudinal direction of the side wall of boiler furnace, adjacent vertical water-cooled pipes are spliced and sealed, and all vertical water-cooled pipes are divided into edge main pipes on both sides of furnace, and a plurality of intermediate pipes between the edge main pipes on both sides;Multiple groups of transverse water-cooled pipes are horizontally arranged between the two edge main pipes, and the transverse water-cooled pipes are arranged in parallel along the longitudinal direction at equal intervals, and the two ends of each transverse water-cooled pipe are communicated with the edge main pipes on both sides;V-shaped slotted fin is fixedly arranged in the gap surrounded by vertical water-cooled pipe and transverse water-cooled pipe;S-shaped fin is integrally fixed on the fire-facing side of transverse water-cooled pipe facing the flame of furnace, so as to overcome the defects of uneven heat exchange, easy coking, high corrosion rate and poor decoking effect of traditional water-cooled wall.

Description

Technical Field

[0001] This invention relates to the field of boiler processing technology, specifically to a boiler furnace water-cooled wall structure that is resistant to high-temperature corrosion and coking. Background Technology

[0002] As the core heat-receiving and pressure-bearing component of the boiler, the water-cooled wall of the boiler furnace is in direct contact with high-temperature flue gas, molten ash and alkali metal corrosive media for a long time. During operation, it generally suffers from two common problems: high-temperature corrosion of the tube wall and coking of the heating surface. These problems directly shorten the service life of the water-cooled wall, reduce the heat exchange efficiency of the boiler, and in severe cases, can lead to tube rupture and shutdown accidents.

[0003] In the existing technology field, water-cooled walls are often formed by combining water-cooled pipes with fins. By opening guide grooves on the surface of the fins and adding coatings, the possibility of coking and corrosion on the surface can be reduced, thereby increasing the service life.

[0004] However, this method is not suitable for the random movement of flue gas in the vertical furnace, the uneven distribution of flue gas velocity along the surface of the water-cooled wall, and the continuous accumulation of ash and coke in dead corners such as the roots of fins and gaps between tubes. Conventional soot blowers are fixed in place and do not have matching guide channels to constrain the blowing airflow. The sound wave energy is dispersed and cannot be used to clean the dead corners where coke has accumulated. Frequent shutdowns are required for manual cleaning, which affects the continuous operation time of the boiler.

[0005] Based on this, the present invention designs a boiler furnace water-cooled wall structure that is resistant to high-temperature corrosion and coking, in order to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a boiler furnace water-cooled wall structure that is resistant to high-temperature corrosion and coking. It features a zoned water circulation for balanced heat exchange, dual-guide fins for directional slag removal, a three-layer gradient high-temperature resistant and anti-corrosion coating, and an integrated design of guide channels and ultrasonic directional purging. This design completely overcomes the shortcomings of traditional water-cooled walls, such as uneven heat exchange, easy coking, rapid high-temperature corrosion, and poor coking removal.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A boiler furnace water-cooled wall structure that is resistant to high-temperature corrosion and coking includes a water-circulating compressor unit, an acoustic soot blowing device, and a water-cooled pipe assembly. The compressor unit is connected to the water-cooled pipe assembly to form a closed cooling water circulation loop. The water-cooled pipe assembly includes multiple vertical water-cooled pipes evenly arranged longitudinally along the side wall of the boiler furnace. Adjacent vertical water-cooled pipes are connected and sealed by S-shaped cross-section connecting baffles. All vertical water-cooled pipes are divided into edge main pipes on both sides of the furnace and several intermediate pipes located between the edge main pipes on both sides. The connecting baffles are formed with longitudinal guide grooves extending vertically. Multiple sets of horizontal water-cooled pipes are horizontally installed between the two sets of edge main pipes, and are arranged parallel to each other at equal intervals along the longitudinal direction. Each horizontal water-cooled pipe is connected to the two edge main pipes at both ends, and a suction pump assembly is installed at the connection between the horizontal water-cooled pipe and the edge main pipe. The suction pump assembly is used to introduce the water in the edge main pipe into the horizontal water-cooled pipe for secondary heat exchange. V-shaped slotted fins are fixedly installed in the gap formed by the vertical and horizontal water-cooling pipes. Multiple V-shaped elongated guide grooves are opened on the side of the V-shaped slotted fins facing the furnace flame. Sonic soot blowers are arranged at the upper end of the V-shaped elongated guide grooves. S-shaped fins are integrally fixed on the fire-facing side of the middle pipe facing the furnace flame. The surface of the S-shaped fins is concave to form a transverse guide groove. Sonic soot blowers are arranged at both ends of the transverse guide groove.

[0008] Preferably, the transverse guide grooves are evenly arranged along the wave direction of the S-shaped fins, and the sonic blowing airflow output by the sonic soot blower covers the entire heated surface of the S-shaped fins in a directional manner along the transverse guide grooves, which is used to flush away the ash and slag attached to the transverse guide grooves.

[0009] Preferably, the S-shaped fin is composed of a three-layer anti-corrosion and high-temperature resistant composite layer consisting of a nickel-iron-based alloy underlayer, a ceramic intermediate coating, and an alumina surface layer, arranged sequentially from the substrate to the fire-facing side. The nickel-iron-based alloy underlayer has a thickness of 0.8–1.5 mm, the ceramic intermediate coating has a thickness of 0.3–0.6 mm, and the alumina surface layer has a thickness of 0.1–0.3 mm. The three-layer composite layer as a whole can withstand high-temperature flue gas corrosion above 1200°C.

[0010] Preferably, the V-shaped elongated guide groove has its opening facing the direction of the flue gas flow in the furnace, which is used to guide the high-temperature flue gas to continuously scour the root of the V-shaped grooved fins and the wall of the vertical water-cooled pipe, thereby inhibiting the adhesion and coking of molten ash.

[0011] Preferably, the top view of the connecting baffle is S-shaped, and a longitudinal guide groove is formed on the surface of the connecting baffle.

[0012] Preferably, the suction pump assembly includes a small circulating pump and a flow regulating valve. Each set of horizontal water-cooled pipes is independently equipped with a suction pump assembly, which can independently adjust the water circulation flow rate inside a single horizontal water-cooled pipe.

[0013] Preferably, the sonic soot blowing device is synchronously connected to the furnace control system, and can alternately blow the transverse guide channel and the V-shaped elongated guide channel in different time periods.

[0014] Preferably, expansion gaps are provided on the backfire side of the S-shaped fin, the connecting baffle, and the V-shaped slotted fin.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention employs a combination of vertical and horizontal water-cooled pipes, coupled with V-shaped grooved fins and S-shaped fins to form a dual-pipe, dual-flow-guiding fin composite reinforced water-cooled wall structure, comprehensively improving the protection performance of the furnace sidewall heating surface. The two ends of the horizontal water-cooled pipes are connected to the main edge pipes on both sides of the furnace. Utilizing the suction pump assembly on the pipes, water saturated with heat or with insufficient heat exchange in the edge pipes can be introduced into the horizontal water-cooled pipes for secondary heat exchange, fully absorbing the waste heat from the flue gas. This structure can evenly distribute the cooling water flow between the edge pipes and the intermediate pipes, balancing the heat exchange load of each pipe, eliminating localized high-temperature areas on the pipe wall at the source, effectively inhibiting high-temperature sulfidation corrosion and alkali metal molten corrosion, significantly slowing down the rate of pipe wall corrosion and thinning, and greatly extending the overall service life of the water-cooled wall.

[0016] 2. In this invention, S-shaped finned corrugated plate-formed transverse guide grooves are provided on the fire side to manage the transverse flue gas and provide a guiding channel for the acoustic purging airflow. On the other hand, V-shaped slotted fins are arranged in the gap between the vertical and horizontal water-cooling pipes. The fins have V-shaped elongated guide grooves with the groove openings facing the flue gas flow direction. The high-temperature flue gas can continuously and rapidly scour the fin roots and the vertical water-cooling pipe walls, relying on the kinetic energy of the flue gas to blow away the molten ash and prevent the ash and ash from cooling and solidifying to form a coke layer. The dual-fin zoned guide covers the entire heated surface of the water-cooled wall, achieving active anti-coking and significantly reducing the thickness of coke accumulation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a front view of the present invention; Figure 2 This is a schematic diagram of the front view structure of the present invention; Figure 3 This is a top view of the present invention; Figure 4 This is a schematic diagram of the S-shaped fin structure in this invention; Figure 5 This is a partial cross-sectional view of the S-shaped fin in this invention; Figure 6 This is a schematic diagram of the V-shaped slotted fin structure in this invention.

[0019] The attached diagram lists the components represented by each number as follows: 1. Vertical water cooling pipe; 101. Edge main pipe; 102. Middle pipe; 2. Horizontal water cooling pipe; 3. Connecting baffle; 301. Longitudinal guide groove; 4. S-shaped fin; 401. Horizontal guide groove; 402. Nickel-iron base alloy bottom layer; 403. Ceramic intermediate coating; 404. Alumina surface layer; 5. V-groove fin. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1-6 The present invention provides a technical solution: A boiler furnace water-cooled wall structure that is resistant to high-temperature corrosion and coking includes a water-circulating compressor unit, an acoustic soot blowing device, and a water-cooled pipe assembly, characterized in that: the compressor unit is connected to the water-cooled pipe assembly to form a closed cooling water circulation loop; The water-cooled tube assembly includes multiple vertical water-cooled tubes 1 that are evenly arranged longitudinally along the side wall of the boiler furnace. Adjacent vertical water-cooled tubes 1 are connected and sealed by S-shaped cross-section connecting baffles 3. All vertical water-cooled tubes 1 are divided into edge main tubes 101 on both sides of the furnace and several intermediate tubes 102 located between the edge main tubes 101 on both sides. The connecting baffles 3 have longitudinal guide grooves 301 extending vertically on their surface. Multiple sets of horizontal water-cooled pipes 2 are horizontally installed between the two sets of edge main pipes 101, and are arranged parallel to each other at equal intervals along the longitudinal direction. Each horizontal water-cooled pipe 2 is connected to the two edge main pipes 101 at both ends. A suction pump assembly is installed at the connection between the horizontal water-cooled pipe 2 and the edge main pipe 101. The suction pump assembly is used to introduce the water in the edge main pipe 101 into the horizontal water-cooled pipe 2 for secondary heat exchange. V-shaped slotted fins 5 are fixedly installed in the gap formed by the vertical water-cooled pipe 1 and the horizontal water-cooled pipe 2. Multiple V-shaped elongated guide grooves are opened on the side of the V-shaped slotted fins facing the furnace flame. Sonic soot blowers are arranged at the upper end of the V-shaped elongated guide grooves. S-shaped fins 4 are integrally fixed on the fire-facing side of the horizontal water-cooled pipe 2 facing the furnace flame. The surface of the S-shaped fins 4 is recessed to form a horizontal guide groove 401. Sonic soot blowers are arranged at both ends of the horizontal guide groove 401.

[0022] This invention employs a combination of vertical water-cooled pipes 1 and horizontal water-cooled pipes 2, along with V-shaped grooved fins 5 and S-shaped fins 4, to form a dual-pipe, dual-flow-guiding fin composite reinforced water-cooled wall structure, comprehensively improving the protection performance of the furnace sidewall heating surface. The two ends of the horizontal water-cooled pipes 2 are respectively connected to the edge main pipes 101 on both sides of the furnace. Relying on the suction pump assembly on the pipes, water saturated with heat absorption or with insufficient heat exchange in the edge main pipes 101 can be introduced into the horizontal water-cooled pipes 2 for secondary heat exchange, fully absorbing the waste heat from the flue gas. This structure can evenly distribute the cooling water flow between the edge main pipes 101 and the intermediate pipe 102, balancing the heat exchange load of each pipe, eliminating localized high-temperature areas on the pipe wall from the root, effectively inhibiting high-temperature sulfidation corrosion and alkali metal molten corrosion, significantly slowing down the rate of pipe wall corrosion and thinning, and greatly extending the overall service life of the water-cooled wall.

[0023] In this invention, S-shaped fins with corrugated fin surfaces are provided on the fire side to create transverse flow channels 401, which guide the transverse flue gas and provide a guiding channel for the acoustic purging airflow. On the other hand, V-shaped slotted fins are arranged between the vertical water-cooled pipe 1 and the horizontal water-cooled pipe 2. The fins have V-shaped elongated flow channels with the openings facing the flue gas flow direction. High-temperature flue gas can continuously and rapidly scour the fin roots and the wall of the vertical water-cooled pipe 1. Through the dual-fin flow guiding structure combined with directional flue gas scouring, the molten ash is blown away by the kinetic energy of the flue gas, preventing the ash from cooling and solidifying to form a coke layer. The dual-fin zoned flow guidance covers the entire heated surface of the water-cooled wall, achieving active anti-coking and significantly reducing the thickness of coke buildup.

[0024] The transverse guide grooves 401 are evenly arranged along the wave direction of the S-shaped fins 4. The sonic blowing airflow output by the sonic soot blower covers the entire heated surface of the S-shaped fins 4 along the transverse guide grooves 401, which is used to flush away the ash and slag attached to the transverse guide grooves 401. The S-shaped fins 4 are arranged on the fire side, and the transverse guide grooves 401 are formed on the wave plate surface of these fins, which sorts the transverse flue gas and provides a guiding channel for the sonic blowing airflow.

[0025] The S-shaped fin 4 is constructed from the substrate to the fire-facing side as a three-layer composite layer for corrosion protection and high-temperature resistance: a nickel-iron alloy base layer 402, a ceramic intermediate coating 403, and an alumina surface layer 404. The nickel-iron alloy base layer 402 has a thickness of 0.8–1.5 mm, the ceramic intermediate coating 403 has a thickness of 0.3–0.6 mm, and the alumina surface layer 404 has a thickness of 0.1–0.3 mm. The three-layer composite layer as a whole can withstand high-temperature flue gas corrosion above 1200℃. In this invention, the nickel-iron alloy base layer 402 has strong adhesion to the fin substrate, preventing the coating from peeling off completely at high temperatures; the ceramic intermediate coating 403 blocks the penetration of sulfur and chlorine corrosive media; and the alumina surface layer 404 is resistant to high-temperature flue gas erosion above 1200℃ and resists the adhesion of molten ash. This three-layer composite protection system overcomes the shortcomings of existing single coatings, which are prone to cracking and have poor corrosion resistance. It maintains an intact protective layer under long-term high-temperature corrosion conditions, significantly reducing the risk of pipe wall corrosion thinning and pipe bursting.

[0026] Among them, the V-shaped elongated guide groove faces the direction of the flue gas flow in the furnace, which is used to guide the high-temperature flue gas to continuously scour the root of the V-shaped slotted fin 5 and the wall of the vertical water cooling pipe 1, and inhibit the adhesion and coking of molten ash.

[0027] The connecting baffle 3 has an S-shaped cross-section when viewed from above, and a longitudinal guide groove 301 is formed on the surface of the connecting baffle 3. The continuous longitudinal guide groove 301 on the surface of the baffle 3 in this invention can guide the high-temperature flue gas in the furnace vertically downward along the water-cooled wall, breaking the flue gas vortex and local dead angles caused by traditional flat membrane baffles; after the flue gas velocity is evenly distributed, molten fly ash is difficult to remain and adhere in the gaps between tubes and at the root of the fins, reducing the conditions for coking from the flue gas flow level, and simultaneously improving the overall heat exchange uniformity of the water-cooled wall.

[0028] The suction pump assembly includes a small circulating pump and a flow regulating valve. Each set of horizontal water-cooled pipe 2 is equipped with an independent suction pump assembly, which can independently adjust the water circulation flow rate inside a single horizontal water-cooled pipe 2. The independent flow regulating valve can adjust the water circulation volume separately according to the combustion load of different areas of the furnace.

[0029] Among them, the acoustic soot blowing device is synchronously connected to the furnace control system, and can alternately blow the transverse guide channel 401 and the V-shaped long strip guide channel in different times.

[0030] Expansion gaps are provided on the backfire side of the S-shaped fins 4, the connecting baffles 3, and the V-shaped slotted fins 5. The alternating thermal stress caused by boiler start-up and shutdown and load fluctuations can be released through the gaps, preventing thermal fatigue cracks at the welds between the fins, baffles, and water-cooled pipes, improving the overall structural stability of the water-cooled wall, and reducing structural damage and water leakage pipeline failures under high-temperature conditions.

Claims

1. A boiler furnace water-cooled wall structure resistant to high-temperature corrosion and coking, comprising a water-circulating compressor unit, an acoustic soot blowing device, and a water-cooled pipe assembly, characterized in that: The compressor unit is connected to the water-cooled pipe assembly to form a closed cooling water circulation loop. The water-cooled pipe assembly includes multiple vertical water-cooled pipes (1) that are evenly arranged longitudinally along the side wall of the boiler furnace. Adjacent vertical water-cooled pipes (1) are joined and sealed by connecting baffles (3) with S-shaped cross sections. All vertical water-cooled pipes (1) are divided into edge main pipes (101) on both sides of the furnace and several intermediate pipes (102) located between the edge main pipes (101) on both sides. The connecting baffles (3) have longitudinal guide grooves (301) that extend vertically on their surface. Multiple sets of horizontal water-cooled pipes (2) are horizontally installed between the two sets of edge main pipes (101) and are arranged parallel to each other at equal intervals along the longitudinal direction. Each horizontal water-cooled pipe (2) is connected to the two edge main pipes (101) at both ends. A suction pump assembly is installed at the connection between the horizontal water-cooled pipe (2) and the edge main pipe (101). The suction pump assembly is used to introduce the water in the edge main pipe (101) into the horizontal water-cooled pipe (2) for secondary heat exchange. V-shaped slotted fins (5) are fixedly provided in the gap between the vertical water-cooled pipe (1) and the horizontal water-cooled pipe (2). The side of the V-shaped slotted fins (5) facing the furnace flame has multiple V-shaped elongated guide grooves. The upper end of the V-shaped elongated guide grooves is correspondingly arranged with sonic soot blowers. The side of the horizontal water-cooled pipe (2) facing the furnace flame is integrally fixed with S-shaped fins (4). The surface of the S-shaped fins (4) is concave to form a horizontal guide groove (401). The sonic soot blowers are correspondingly arranged at both ends of the horizontal guide groove (401).

2. The boiler furnace water-cooled wall structure for preventing high-temperature corrosion and coking according to claim 1, characterized in that: The transverse guide groove (401) is evenly arranged along the wave direction of the S-shaped fin (4). The sonic blowing airflow output by the sonic soot blower covers the entire heated surface of the S-shaped fin (4) along the transverse guide groove (401) to flush the ash and slag attached to the transverse guide groove (401).

3. The boiler furnace water-cooled wall structure for preventing high-temperature corrosion and coking according to claim 1, characterized in that: The S-shaped fin (4) consists of a three-layer anti-corrosion and high-temperature resistant composite layer, consisting of a nickel-iron alloy bottom layer (402), a ceramic intermediate coating (403), and an alumina surface layer (404), arranged sequentially from the substrate to the fire-facing side. The nickel-iron alloy bottom layer (402) has a thickness of 0.8 to 1.5 mm, the ceramic intermediate coating (403) has a thickness of 0.3 to 0.6 mm, and the alumina surface layer (404) has a thickness of 0.1 to 0.3 mm. The three-layer composite layer as a whole can withstand high-temperature flue gas corrosion above 1200℃.

4. The boiler furnace water-cooled wall structure for preventing high-temperature corrosion and coking according to claim 1, characterized in that: The V-shaped elongated guide groove faces the direction of the flue gas flow in the furnace, and is used to guide the high-temperature flue gas to continuously scour the root of the V-shaped slotted fins (5) and the wall of the vertical water cooling pipe (1), thereby inhibiting the adhesion and coking of molten ash.

5. The boiler furnace water-cooled wall structure for preventing high-temperature corrosion and coking according to claim 1, characterized in that: The top view of the connecting baffle (3) is S-shaped, and a longitudinal guide groove (301) is formed on the surface of the connecting baffle (3).

6. The boiler furnace water-cooled wall structure for preventing high-temperature corrosion and coking according to claim 1, characterized in that: The suction pump assembly includes a small circulating pump and a flow regulating valve. Each set of horizontal water cooling pipes (2) is independently equipped with a set of suction pump assemblies, which can independently adjust the water circulation flow rate inside a single horizontal water cooling pipe (2).

7. The boiler furnace water-cooled wall structure for preventing high-temperature corrosion and coking according to claim 1, characterized in that: The sonic soot blowing device is synchronously connected to the furnace control system and can alternately blow the transverse guide channel (401) and the V-shaped long strip guide channel at different times.

8. A boiler furnace water-cooled wall structure for preventing high-temperature corrosion and coking according to claim 1, characterized in that: Expansion slots are provided on the back side of the S-shaped fin (4), the connecting baffle (3), and the V-shaped slotted fin (5).

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