Anti-corrosion and anti-blocking flue gas continuous soot blowing system for heat transfer element of air pre-heater

Abstract

The utility model discloses an anti-corrosion and anti-blocking flue gas continuous soot blowing system for a heat transfer element of an air pre-heater, which is characterized in that a flue gas extraction pipeline for extracting hot flue gas in an inlet flue of the air pre-heater or hot flue gas in an outlet flue of the air pre-heater is arranged in the inlet flue of the air pre-heater or in the outlet flue of the air pre-heater; a flue gas booster fan is arranged on the flue gas extraction pipeline, and the output end of the flue gas extraction pipeline is divided into three paths, namely a primary air inlet channel, a secondary air inlet channel and a hot flue gas inlet channel; the primary air inlet channel, the secondary air inlet channel and the hot flue gas inlet channel are respectively communicated with a primary air flue soot blowing flue gas main pipe, a secondary air flue soot blowing flue gas main pipe and a hot flue gas flue soot blowing flue gas main pipe which are arranged at a primary air inlet, a secondary air inlet and a hot flue gas inlet; and a plurality of soot blowing nozzles are arranged on the primary air flue soot blowing flue gas main pipe, the secondary air flue soot blowing flue gas main pipe and the hot flue gas flue soot blowing flue gas main pipe. The air pre-heater can effectively prevent the heat transfer element of the air pre-heater from being corroded and blocked.

Description

Technical Field

[0001] The utility model relates to a flue gas continuous soot blowing system for anti-corrosion and anti-blocking of heat transfer elements of air preheaters. Background Art

[0002] China is a world manufacturing power, and energy consumption based on coal is indispensable for its energy structure. It is the cornerstone of the energy base. One of the important equipment in coal-fired boilers is the air preheater. Air preheater performance 1): Improve heat exchange performance. By using the heat of flue gas in the flue at the tail of the boiler to heat the air entering the boiler, the heat exchange performance of the boiler is improved and the heat loss is reduced. Air preheater performance 2): Reduce heat loss. The air preheater effectively utilizes the heat of flue gas, thereby reducing heat loss. Air preheater performance 3): Improve boiler efficiency. By heating the air entering the boiler, the inlet air temperature in the boiler is increased, thereby improving the boiler efficiency. Air preheater performance 4): Improve combustion efficiency. The air preheater heats the air required for combustion and reduces the exhaust gas temperature, thereby improving the combustion efficiency in the boiler. Air preheater performance 5): Reduce exhaust gas temperature. By preheating the air, the heat carried away by the exhaust gas is reduced, thereby reducing the exhaust gas temperature. It is an indispensable and important equipment in the boiler system.

[0003] The main problems in the operation of boiler air preheater are blockage and corrosion. The first is the NH 3 SO in flue gas 3 and H 2 O reacts to form ammonium bisulfate (NH 4 HSO 4 ), which causes blockage and corrosion in the low temperature section of the air preheater. The generation of ammonium bisulfate not only increases the operating resistance of the air preheater and reduces the circulation heat exchange capacity, but also aggravates the corrosion and ash blockage of the heat exchange components. In addition, SO generated by coal combustion 2 Active ingredient V in denitrification device 2 O 5 This further accelerates the catalytic action of NH 4 HSO 4 The generation of acid also leads to an increase in the flue gas dew point temperature, aggravating the acid corrosion and blockage of the air preheater.

[0004] The moisture in the flue gas has a dual effect on the blockage and corrosion of the air preheater. When the moisture in the flue gas drops to the dew point temperature after the heat exchange, the condensable part of the flue gas condenses to form dew droplets, which is called "condensation". The highly corrosive sulfuric acid and sulfurous acid solutions formed after this "condensation" phenomenon cause corrosion to metal equipment. Secondly, the slag formed at low temperatures causes corrosion, and the sulfuric acid liquid condensed on the low-temperature heating surface will also adhere to the dust in the flue gas to form sticky ash that is difficult to remove, making the flue gas channel unsmooth or even blocked.

[0005] The presence of moisture in the flue gas of the air preheater not only directly causes corrosion through the "condensation" phenomenon, but also indirectly affects the blockage and corrosion of the air preheater by promoting the aggravation of ash accumulation and low-temperature corrosion. Therefore, controlling the moisture content in the flue gas is crucial to prevent the blockage and corrosion of the air preheater.

[0006] Boiler air preheater, referred to as air preheater. The most important thing for a boiler in combustion is to have a suitable temperature and sufficient oxygen to meet the combustion. The air contains a large amount of oxygen, and the demand for oxygen is as indispensable as blood in the human body. In order to improve the combustion efficiency of the boiler, the air preheater needs to raise the normal temperature air to meet the needs of efficient combustion. At the same time, it also reduces the boiler exhaust temperature and further improves the thermal efficiency of the boiler. It is an indispensable and important equipment in the boiler system.

[0007] The main reasons for air preheater corrosion and blockage include but are not limited to the following:

[0008] 1. The cold end temperature of the air preheater is low. Especially in winter, the ambient temperature is low, including the humidity and water components in the cold air, which easily forms a humid environment in the air preheater. When the flue gas dew point generates dew droplets, highly corrosive sulfuric acid and sulfurous acid solutions are formed to corrode the heat transfer components, and then encounter the ash particles in the flue gas to bond, thereby increasing the possibility of corrosion and ash accumulation and blockage.

[0009] 2. Influence of SCR denitration system. The automatic regulation performance of ammonia spraying in the denitration system is poor, and ammonia escape and catalysts will lead to the production of ammonium bisulfate. As the flue gas temperature in the air preheater decreases (150℃-200℃), ammonium bisulfate will naturally form a liquid, aggravating the corrosion and blockage of the air preheater.

[0010] 3. Poor soot blowing device. The steam soot blowing is not drained enough, or the steam itself condenses into water when it is cooled, or the water vapor component in the flue meets the sulfur dioxide and sulfur trioxide gas in the flue gas, which will produce acid smoke. When the air preheater rotates to the cold end and the temperature drops again, it will condense into an acid solution, thereby corroding the corrugated plate and causing adhesion and blockage.

[0011] 4. Currently, there are five forms of soot blowing for air preheaters. The most common one is steam soot blowing, but the corrosion and blockage of air preheaters have never been eliminated because steam itself is a moisture carrier. The other soot blowing forms cannot solve the corrosion and blockage of heat transfer components caused by the flue gas temperature changes during the heat exchange process of the air preheater. Utility Model Content

[0012] The utility model aims to provide a flue gas continuous soot blowing system for air preheater heat transfer element corrosion and blockage prevention, which can effectively prevent the air preheater heat transfer element from corrosion and blockage.

[0013] The technical solution of the utility model is:

[0014] A flue gas continuous soot blowing system for preventing corrosion and blocking of heat transfer elements of an air preheater comprises an air preheater body, on which a flue gas inlet, a flue gas outlet, a primary air inlet, a primary air outlet, a secondary air inlet and a secondary air outlet are arranged, wherein: a flue gas extraction pipeline for extracting hot flue gas in the air preheater inlet flue or the air preheater outlet flue is arranged in the air preheater inlet flue or the air preheater outlet flue, a flue gas booster fan is arranged on the flue gas extraction pipeline, and an output of the flue gas extraction pipeline is provided. The end is divided into three channels, namely the primary air inlet channel, the secondary air inlet channel and the hot flue gas inlet channel. The primary air inlet channel, the secondary air inlet channel and the hot flue gas inlet channel are connected with the primary air duct sootblowing flue gas mother pipe, the secondary air duct sootblowing flue gas mother pipe and the hot flue gas duct sootblowing flue gas mother pipe installed at the primary air inlet, the secondary air duct sootblowing flue gas mother pipe and the hot flue gas duct sootblowing flue gas mother pipe respectively. A plurality of sootblowing nozzles are installed on the primary air duct sootblowing flue gas mother pipe, the secondary air duct sootblowing flue gas mother pipe and the hot flue gas duct sootblowing flue gas mother pipe.

[0015] The nozzle opening of the sootblowing nozzle is in a flat rectangular shape, and a plurality of sootblowing nozzles are arranged in a line on the corresponding sootblowing flue gas main pipe, forming a hot flue gas nozzle that is closely connected on the left and right, and the heat transfer elements of the air preheater are purged without omission.

[0016] The lower part of the sootblowing nozzle is in the form of a waist that is concave inwards, the upper part is in the form of an enlarged trumpet mouth, and the nozzle mouth is in a flat rectangular shape.

[0017] The utility model discloses a continuous soot blowing system for preventing corrosion and blocking of heat transfer elements of air preheater, which not only makes the blowing and cleaning keep the heat transfer elements dry and clean, but also recirculates a small amount of hot flue gas to increase the primary and secondary air temperatures at the cold end, without consuming new energy, greatly improving the problem of low average temperature at the cold end, and eliminating the corrosion and blockage of air preheater. For boiler combustion, the primary air temperature is increased, which is very beneficial to the pulverizing and drying treatment of coal mill, and the accumulation time of raw coal in the coal mill is reduced, and the current of coal mill will be greatly reduced. The increase of secondary air temperature is conducive to the ignition and combustion of coal powder and stability, shortening the combustion time of coal powder and improving the combustion efficiency. Increasing the air temperature means reducing the exhaust gas temperature and absorbing more heat in the flue gas, which is to improve the heat conversion efficiency. The corrosion and blockage of air preheater are eliminated, the differential pressure of air preheater is reduced, the air leakage rate is reduced, and the current of primary fan, secondary fan and suction fan are all reduced synchronously. Not only that, tens of tons of soot blowing steam are saved every day, and some are hundreds of tons. The additional power generation of these steams is accumulated to tens of millions of degrees, and tens of thousands of tons of pure desalted water are saved. It is a practical measure to save energy, reduce consumption, and improve environmental protection efficiency.

[0018] The utility model uses the hot flue gas in the flue before entering the air preheater as a soot blowing medium, which reduces the moisture content in the flue gas of the air preheater to the greatest extent from the source, so that the flue gas of the air preheater as a whole exchanges heat with the air in a dry environment. This is an innovation that not only saves a lot of heat energy and a lot of pure water, but also completely changes the phenomenon of low-temperature condensation of flue gas caused by the entry of cold air at the cold end of the air preheater. Because the hot flue gas is used to continuously blow the cold end heat transfer element with a small flow rate and high flow rate, the cold and wet flue gas no longer exists, the fluidity of the ash particles is improved, and the cold end heat transfer element is dry and unobstructed.

[0019] The utility model uses free hot flue gas to continuously blow from the primary and secondary cold air inlets below, promotes temperature rise along the wind direction, and changes the phenomenon of easy condensation at the cold end. Another way is to blow from the upper flue gas inlet along the flue gas flow direction. The flue gas contains a small amount of ash particles, which are blown downward along the flue gas flow direction. Under the action of double flow rate flushing, each corrugated plate is dry and clean. Because each circle is being purged, the ash accumulated on the corrugated plate is not sticky in a dry environment, and the ash particles have strong fluidity, keeping the intervals of the corrugated plates unobstructed. Change the previous practice of cleaning → contamination → blowing → re-contamination → re-blowing. Of course, there are several existing soot blowing forms. If the blowing is continuous and uninterrupted, the cost is staggering and the operating cost is too high.

[0020] The soot blowing nozzles of the utility model are fixed on respective mother pipes, and the mother pipes are fixed and face the rotation direction of the air preheater. Each corrugated plate is purged three times for each rotation of the air preheater, and no piece is leaked. From the ignition of the boiler, the soot blowing is continuous and uninterrupted to keep the corrugated plate clean and free from soot.

[0021] The utility model soot blowing nozzle is a special nozzle, the purpose is to increase the nozzle outlet flow rate, the left and right adjacent nozzles cover the same area. The nozzle flow diameter is enlarged in turn according to the cell area, and the flow rate matches the blowing area. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0023] Figure 1 A schematic diagram of a flue gas continuous soot blowing system for preventing corrosion and blocking of heat transfer elements of an air preheater provided in an embodiment of the utility model;

[0024] Figure 2 A schematic diagram of the arrangement of the main flue gas continuous soot blowing pipe for the air preheater heat transfer element anti-corrosion and anti-blocking provided by the embodiment of the utility model;

[0025] Figure 3 A schematic diagram of the arrangement of the flue gas continuous soot blowing nozzles for the air preheater heat transfer element anti-corrosion and anti-blocking provided by the embodiment of the utility model;

[0026] Figure 4 A front view schematic diagram of a flue gas continuous soot blowing nozzle structure for an air preheater heat transfer element that prevents corrosion and blockage, provided by an embodiment of the utility model;

[0027] Figure 5 A schematic diagram of a flat rectangular nozzle opening of a flue gas continuous soot blowing nozzle for preventing corrosion and blocking of an air preheater heat transfer element provided in an embodiment of the present invention.

[0028] Reference numerals:

[0029] 1. Air preheater body, 2. Flue gas inlet, 3. Primary air outlet, 4. Secondary air outlet, 5. Flue gas extraction pipeline, 6. Flue gas booster fan, 7. Pressurized flue gas to the flue gas side soot blowing main pipe, 8. Pressurized flue gas to the primary air side and secondary air side soot blowing main pipe, 9. Flue gas outlet, 10. Primary air inlet, 11. Secondary air inlet, 12. Flue gas duct soot blowing main pipe, 13. Primary air duct soot blowing main pipe, 14. Secondary air duct soot blowing main pipe, 15. Air preheater rotation direction, 16. Soot blowing nozzle, 17 Nozzle mouth, 18, Flue gas isolation valve. DETAILED DESCRIPTION

[0030] A flue gas continuous soot blowing system for preventing corrosion and blocking of heat transfer elements of an air preheater comprises an air preheater body 1, on which a flue gas inlet 2, a flue gas outlet 9, a primary air inlet 10, a primary air outlet 3, a secondary air inlet 11, and a secondary air outlet 4 are arranged, a flue gas extraction pipeline 5 for extracting hot flue gas in the air preheater inlet flue or the air preheater outlet flue is arranged in the air preheater inlet flue or the air preheater outlet flue, a flue gas booster fan 6 is arranged on the flue gas extraction pipeline, and an output end of the flue gas extraction pipeline is provided. It is divided into three routes, namely the primary air inlet channel, the secondary air inlet channel and the hot flue gas inlet channel. The primary air inlet channel, the secondary air inlet channel and the hot flue gas inlet channel are connected with the primary air duct sootblowing flue gas mother pipe 13, the secondary air duct sootblowing flue gas mother pipe 14 and the hot flue gas duct sootblowing flue gas mother pipe 12 installed at the primary air inlet, the secondary air duct and the hot flue gas inlet respectively. A plurality of sootblowing nozzles 16 are installed on the primary air duct sootblowing flue gas mother pipe, the secondary air duct sootblowing flue gas mother pipe and the hot flue gas duct sootblowing flue gas mother pipe.

[0031] The nozzle opening 17 of the sootblowing nozzle is in a flat rectangular shape. A plurality of sootblowing nozzles are arranged in a line on the corresponding sootblowing flue gas main pipe, forming a hot flue gas nozzle that is closely connected on the left and right, so that the heat transfer elements of the air preheater are purged without omission.

[0032] The lower part of the sootblowing nozzle is in the form of a waist that is concave inwards, the upper part is in the form of an enlarged trumpet mouth, and the nozzle mouth is in a flat rectangular shape.

[0033] A method for continuous flue gas soot blowing to prevent corrosion and blockage of heat transfer elements of an air preheater, firstly, soot blowing particles are extracted, which are hot flue gas in the flue of a boiler, and are hot flue gas in the flue of an air preheater inlet or in the flue of an air preheater outlet; then, the extracted high-temperature flue gas is pressurized and divided into three paths for soot blowing of the air preheater, and the high-temperature flue gas is continuously purged, namely, a primary air inlet channel, a secondary air inlet channel, and a hot flue gas inlet channel; the nozzle is arranged on a soot blowing flue gas main pipe facing the rotation direction of the air preheater, so that the cold air that enters the heat transfer element first can be preheated.

[0034] High-temperature flue gas pressurization adopts flue gas booster fans. One or more flue gas booster fans are used to pressurize the extracted flue gas, and then sent to the cold end of the primary air inlet, the cold end of the secondary air inlet and the hot end of the flue gas inlet respectively, to perform uninterrupted and continuous soot blowing on the heat transfer elements of the air preheater.

[0035] A plurality of sootblowing nozzles are fixedly arranged in the primary air inlet duct, the secondary air inlet duct and the hot flue gas inlet duct respectively. These nozzles are installed on the sootblowing flue gas main pipe of the primary air duct, the sootblowing flue gas main pipe of the secondary air duct and the sootblowing flue gas main pipe of the hot flue gas duct.

[0036] The soot blowing nozzles are fixed on their respective mother pipes, and the mother pipes are fixed on the bin grid facing the direction of rotation. Every time the air preheater rotates one circle, each corrugated plate is purged three times without leakage. From the ignition of the boiler, the soot blowing is continuous and uninterrupted to keep the corrugated plate clean and free from dust.

[0037] The utility model uses one or two booster fans independently or interconnected, which can be isolated during normal soot blowing and can serve as backup for each other. The high-temperature flue gas (including low-temperature flue gas) sucked out is pressurized and then divided into three channels for air preheater soot blowing, namely the primary air inlet channel, the secondary air inlet channel, and the flue gas inlet channel. The nozzles are arranged along the direction of rotation to preheat the cold air that enters the heat transfer element first. The cold end of the air preheater is the key part to prevent corrosion and blockage of the air preheater. The most commonly used method in the prior art is steam soot blowing, where 300-degree steam instantly condenses into wet steam or condenses, generating sticky ash particles that will quickly react and form a plate; the sticky ash particles allow sulfur oxides in the flue gas to have a residence space, generating concentrated sulfuric acid or sulfurous acid between each other, and gradually forming a cement-like reaction plate; the catalyst and ammonia (NH 3 ) escape, which is even more powerful, combining with sulfur oxides in the flue gas to form highly corrosive ammonium bisulfate (NH 4 HSO 4). Under the continuous purge of high-temperature flue gas in the utility model, these situations can only drift to other parts with the flue gas, and cannot stay in the air preheater, so corrosion and blockage cannot occur. Under the continuous high-temperature and high-flow rate purge of the flue gas inlet, there is a basis for keeping the gap channel of the corrugated plate smooth. The use of high-temperature flue gas for purging does not depend on the flow rate or the pressure, but on the speed of the flue gas flow at the nozzle outlet and the flue gas temperature. The cleaned air preheater corrugated plate after maintenance is continuously purged with high-temperature flue gas and high flow rate. The dust particles in the flue gas have no place to stand, and the dust that has just adhered is flushed. Under the high-speed, high-temperature, and particle-combined flue gas flushing, the dust that has just adhered to the corrugated plate and rotated less than a circle is like a broom blocking dust. The dust floats with the flue gas, keeping the corrugated plate clean.

[0038] The biggest change of the utility model over other previous sootblowing methods is uninterrupted sootblowing, renewal of sootblowing mesons, increase of meson temperature, especially increase of average temperature of cold end, which are all free of cost waste utilization, thus saving and avoiding additional energy consumption and equipment maintenance, and the sootblowing effect is remarkable.

[0039] The utility model utilizes the hot flue gas at the air preheater inlet to continuously purge the corrugated plate of the heat transfer element of the air preheater, thereby increasing the average temperature of the cold end wind temperature and the flue gas temperature, and eliminating the harm of wet flue gas at the cold end of the air preheater. After the air preheater is overhauled, the corrugated plate of the heat transfer element is neatly cleaned. After the boiler is ignited, the air preheater is preheated according to the flue gas temperature. The continuous flue gas purge device of the air preheater is immediately started, and the recycled flue gas helps the heat transfer element to heat up. When the flue gas heats up the air temperature once to meet the pulverizing conditions, the boiler starts the coal mill to pulverize the coal, and the combustion of pulverized coal accelerates the increase of flue gas temperature and wind temperature. Since the pressurized flue gas continuously purges the corrugated plate of the heat transfer element, it can also increase the primary air temperature at the cold end and the secondary air temperature at the cold end, and prevent the average temperature of the cold end from being lower than the dew point temperature. The soot blower uses hot flue gas instead, which greatly reduces the moisture in the flue gas and resolves the phenomenon of flue gas condensation caused by flue gas temperature fluctuations.

[0040] The utility model adopts a special expansion flat nozzle to increase the nozzle flow rate. High-temperature and high-flow flue gas continuously flushes the corrugated plate to form a dry environment. Dust on the heat transfer element corrugated plate cannot adhere to the clean and dry corrugated plate. There is no dust accumulation, no ash blockage, no chance for sulfide and ammonium bisulfate to stay, no possibility of corrosion, and avoids the potential safety hazards caused by blockage and corrosion of the heat transfer element corrugated plate.

[0041] After the boiler is started and ignited, the continuous soot blowing device for the air preheater to prevent corrosion and blockage is started, and the flue gas isolation valve 18 is opened to form a continuous purge of hot flue gas, while also accelerating the heat exchange and temperature rise of the corrugated plate of the heat transfer element. The boiler is fed with pulverized gas for combustion, and the flue gas begins to contain various gas components and dust particles. Among them is sulfide produced during combustion. After the denitrification is put into use, ammonia escape carries (NH 3 ), these gases change with the flue gas temperature and gather in the environment. Under the action of wet flue gas, ammonium bisulfate (NH4 HSO 4 ) will appear in liquid form, sticking to the corrugated plate and accumulating more, while ammonium bisulfate (NH 4 HSO 4 ) Strong corrosive substances, which are difficult to remove after sticking to the corrugated plate. It is the main cause of corrosion and blockage of the corrugated plate of the heat transfer element of the air preheater.

[0042] The continuous flue gas soot blowing technology for anti-corrosion and anti-blocking of heat transfer components of air preheater is aimed at the low temperature of primary air inlet 10 and secondary air inlet 11 at the cold end of air preheater, which derives dust particles under the influence of wet flue gas environment. Some dust particles stick to each other, the flow rate slows down, the flue gas heat exchange is reduced, and the dust adheres to the corrugated plate. As time goes by, the sticky dust accumulates more and more, which is caused by sulfide, moisture in flue gas, and ammonia escape (NH 3 ) provides a generation environment for the aggregation reaction, ammonium bisulfate (NH 4 HSO 4 ) is inevitable. To prevent this from happening, improvements should be made in the sootblower and the sootblowing form. Sootblowing can increase the average temperature of the cold end; sootblowing can change the drying environment of the corrugated plate; sootblowing can increase the flue gas flow rate and enhance the heat exchange effect; sootblowing can always keep the corrugated plate clean. Without the breeding of ash and slag, there will be no environment for the flue gas to stay, and these substances will have no time and space to react. The ultimate goal is to eliminate the safety hazards of corrosion and blockage of the air preheater.

[0043] How to prevent corrosion and blockage of the corrugated plate of the heat transfer element of the air preheater? The purpose of continuous blowing of high-temperature flue gas is that the hot flue gas enters the air preheater and transfers the heat to the cold air. At the same time, its own temperature will drop. The flue gas temperature in the air preheater decreases layer by layer from the upper part to the lower part, and the stickiness of the dust appears as the temperature drops. The key to the continuous soot blowing technology of the heat transfer element of the air preheater to prevent corrosion and blockage is to install the flue gas duct soot blowing flue gas mother pipe (i.e. the flue gas side soot blowing mother pipe) 12 at the flue gas inlet 2. The mother pipe is equipped with several special soot blowing nozzles 16, and the nozzle mouth is a flat rectangular nozzle 17. The high-temperature flue gas ejected from the nozzle is several times the flue gas flow rate in the flue. Although the flow rate is not large, the concentration is high, which pushes the hot flue gas downward to accelerate the transfer of heat exchange and clear the dust on the corrugated plate. The dust sticking to the corrugated plate does not take longer than one rotation of the air preheater before it is swept away by the dust particles entrained by the high-temperature and high-speed steam flow, and the dust accumulation phenomenon no longer exists.

[0044] How to prevent blockage and corrosion? The first step to prevent corrosion is to eliminate the appearance of wet flue gas, that is, to increase the average temperature of the cold end, especially in winter. The function of the air preheater is to heat the air entering the boiler. The air temperature varies with the seasons. The inlet air temperature is usually increased to about 40°C. Theoretically, the average temperature is 80°C to avoid the flue gas dew point temperature. In actual operation, the corrugated plate of the heat transfer element still has dust adhering to the plate due to the low temperature at the cold end, and it is seriously corroded. This phenomenon can be seen by comparing it with the corrugated plate at the hot end. The continuous soot blowing technology for anti-corrosion and anti-blocking flue gas of the air preheater heat transfer element still highlights the characteristics of high temperature and high steam flow. At the cold air inlet (i.e., the primary air inlet 10 and the secondary air inlet 11), the inlet air side soot blowing mother pipe (i.e., the primary air duct soot blowing flue gas mother pipe 13 and the secondary air duct soot blowing flue gas mother pipe 14) is installed to concentrate the limited airflow and blow all-round and without omission to each corrugated plate, creating a heat exchange of the corrugated plate in a ventilated and dry state. There is humidity in the air, which enters the heat exchange element of the air preheater. The cold air releases moisture and the flue gas temperature drops during the heating process, which easily causes condensation in the low-temperature flue gas. The high-temperature and high-flow hot flue gas is continuously blown away, and the vague wet and sticky phenomenon on the corrugated plate is blown away. The high flow rate blows through and deep along the wind direction. Various types of substances appearing in the boiler combustion have no gathering space and no time to combine, so they float with the wind, eliminating the potential safety hazards of dust accumulation, blockage and corrosion of the corrugated plate of the heat transfer element of the air preheater. Its safety, economy and environmental protection are very prominent, contributing to the realization of the dual carbon goals today.

[0045] The illustrative descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without contradicting each other.

[0046] The above are only specific implementations of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A flue gas continuous soot blowing system for preventing corrosion and blocking of heat transfer elements of an air preheater, comprising an air preheater body, on which a flue gas inlet, a flue gas outlet, a primary air inlet, a primary air outlet, a secondary air inlet and a secondary air outlet are arranged, wherein: A flue gas extraction pipeline for extracting hot flue gas in the air preheater inlet flue or the air preheater outlet flue is arranged in the air preheater inlet flue or the air preheater outlet flue, and a flue gas booster fan is arranged on the flue gas extraction pipeline. The output end of the flue gas extraction pipeline is divided into three paths, namely a primary air inlet channel, a secondary air inlet channel, and a hot flue gas inlet channel. The primary air inlet channel, the secondary air inlet channel, and the hot flue gas inlet channel are connected with the primary air duct sootblowing flue gas mother pipe, the secondary air duct sootblowing flue gas mother pipe, and the hot flue gas duct sootblowing flue gas mother pipe installed at the primary air inlet, the secondary air inlet, and the hot flue gas inlet, respectively. A plurality of sootblowing nozzles are installed on the primary air duct sootblowing flue gas mother pipe, the secondary air duct sootblowing flue gas mother pipe, and the hot flue gas duct sootblowing flue gas mother pipe.

2. The anti-corrosion and anti-blocking flue gas continuous soot blowing system for heat transfer elements of air preheater according to claim 1 is characterized by: The nozzle opening of the sootblowing nozzle is in a flat rectangular shape, and a plurality of sootblowing nozzles are arranged in a line on the corresponding sootblowing flue gas main pipe, forming a hot flue gas nozzle that is closely connected on the left and right, and the heat transfer elements of the air preheater are purged without omission.

3. The anti-corrosion and anti-blocking flue gas continuous soot blowing system for heat transfer elements of air preheater according to claim 2 is characterized by: The lower part of the sootblowing nozzle is in the form of a waist that is concave inwards, the upper part is in the form of an enlarged trumpet mouth, and the nozzle mouth is in a flat rectangular shape.

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