Boiler decoking system, coal-fired boiler and coal-fired boiler decoking method

Abstract

The present invention discloses a boiler decoking system, a coal-fired boiler and a coal-fired boiler decoking method, which can perform decoking under different boiler operating conditions and improve decoking effect and economy. The boiler decoking system comprises a decoking powder supply device, a supply pipeline (11) and a conveying and pressurizing device. The inlet of the supply pipeline (11) is connected to the inside of the decoking powder supply device, and the outlet of the supply pipeline (11) extends into the boiler and is opposite to the coking position in the boiler, and is used to convey the powder in the decoking powder supply device. The inlet of the conveying and pressurizing device is connected to a compressed air source (6), and the outlet of the conveying and pressurizing device is connected to the decoking powder supply device, and is used to convey compressed air into the decoking powder supply device, so that the compressed air is mixed with the powder in the decoking powder supply device to form an air-powder mixture, and the air-powder mixture is ejected from the outlet of the supply pipeline (11) and then sprayed toward the coking position in the boiler to remove the coke blocks at the coking position.

Description

Technical Field

[0001] The invention belongs to the technical field of boilers, and in particular relates to a boiler decoking system, a coal-fired boiler and a coal-fired boiler decoking method. Background Art

[0002] High-alkali coal has large reserves and thick coal seams, and the cost of open-pit mining is relatively low. This type of coal has the characteristics of low sulfur, low ash, moderate volatile matter and medium-to-high calorific value. In recent years, it has become a relatively economical and high-quality thermal coal for thermal power units. However, the content of alkali metals such as Na and K in high-alkali coal is relatively high (4%-10%), the ash melting point is low, and it has serious contamination and coking characteristics, which affects the safe and stable operation of boilers, and to a certain extent limits the large-scale use of this type of coal.

[0003] In order to deal with the coking problem of high-alkali coal during boiler combustion, in addition to adjusting the coal blending ratio, regular decoking using steam soot blowing is also one of the means to control the large-scale development of slagging contamination.

[0004] Under different load conditions, the severity of coking on the heating surface of the furnace is different, and the use of steam soot blowing will reduce the temperature in the boiler. Therefore, the boiler needs to meet a certain load when steam soot blowing. Steam soot blowing under a lower load can easily cause the furnace to flame out. At the same time, steam soot blowing is not economical because it requires additional heating of water to form high-temperature steam, and the decoking effect is not obvious. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a boiler decoking system, a coal-fired boiler and a coal-fired boiler decoking method in view of the above-mentioned deficiencies in the prior art, which can decoke under different operating conditions of the boiler and improve the decoking effect and economy.

[0006] In the first aspect, an embodiment of the present invention provides a boiler decoking system, which includes a decoking powder supply device, a supply pipeline and a conveying and pressurizing device. The decoking powder supply device is used to supply powder. The inlet of the supply pipeline is connected to the inside of the decoking powder supply device, and the outlet of the supply pipeline extends into the boiler and is opposite to the coking position in the boiler, and is used to convey the powder in the decoking powder supply device. The inlet of the conveying and pressurizing device is connected to a compressed air source, and the outlet of the conveying and pressurizing device is connected to the decoking powder supply device, and is used to convey compressed air into the decoking powder supply device, so that the compressed air is mixed with the powder in the decoking powder supply device to form an air-powder mixture, and the air-powder mixture is ejected from the outlet of the supply pipeline and then sprayed toward the coking position in the boiler to remove the coke blocks at the coking position.

[0007] In some embodiments, the outlet end of the supply pipeline is bifurcated to form a plurality of first sub-pipelines, and the outlets of the plurality of first sub-pipelines extend into the boiler and are respectively opposite to a plurality of coking positions in the boiler; a decoking nozzle is provided at the outlet of each first sub-pipeline, and the air-powder mixture is sprayed out by the decoking nozzle. An adjustable baffle is provided in each decoking nozzle, and the inclination angle of each adjustable baffle is adjustable to adjust the flow direction of the air-powder mixture sprayed out by the corresponding decoking nozzle.

[0008] In some embodiments, the conveying and pressurizing device includes a conveying and pressurizing main pipe and a conveying pipeline. The inlet of the conveying and pressurizing main pipe is connected to a compressed air source for conveying compressed air. The inlet of the conveying pipeline is connected to the outlet of the conveying and pressurizing main pipe, and the outlet of the conveying pipeline is connected to the interior of the decoking powder supply device, for conveying compressed air to the interior of the decoking powder supply device, and conveying the air-powder mixture formed after the compressed air and powder are mixed into the supply pipeline. The conveying and pressurizing device also includes a plurality of pressurizing pipelines, and the plurality of pressurizing pipelines are arranged in a one-to-one correspondence with the plurality of first sub-pipelines, and the inlet of each of the pressurizing pipelines is connected to the outlet of the conveying and pressurizing main pipe, and the outlet of each of the pressurizing pipelines is connected to the corresponding first sub-pipeline, for conveying compressed air to the corresponding first sub-pipeline, so as to increase the air pressure of the air-powder mixture in the corresponding first sub-pipeline.

[0009] In some embodiments, the boiler decoking system further includes a control component. The control component includes a first compressed air control valve, a second compressed air control valve and a mineral powder control door. The first compressed air control valve is arranged at the inlet of the conveying boosting main pipe, and is used to control the opening of the conveying boosting main pipe. There are multiple second compressed air control valves, and multiple second compressed air control valves are arranged in a one-to-one correspondence with multiple boosting pipes. Each second compressed air control valve is arranged at the outlet of the corresponding boosting pipe, and is used to control the opening of the corresponding boosting pipe. There are multiple mineral powder control doors, and multiple mineral powder control doors are arranged in a one-to-one correspondence with multiple first sub-pipelines. Each mineral powder control door is arranged on the corresponding first sub-pipeline and is located at the front end of the outlet of the corresponding boosting pipe, and is used to control the opening of the corresponding first sub-pipeline.

[0010] In some embodiments, the control assembly further comprises a controller. The controller is electrically connected to the first compressed air control valve, each of the second compressed air control valves, and each of the mineral powder control doors, respectively, and is used to control the opening of the first compressed air control valve, each of the second compressed air control valves, and each of the mineral powder control doors respectively under the control of a corresponding control signal.

[0011] In some embodiments, the control assembly further comprises a plurality of baffle adjusters. The plurality of baffle adjusters are arranged in one-to-one correspondence with the plurality of adjustable baffles, each of the baffle adjusters is arranged outside the boiler, and is connected to the corresponding adjustable baffle through a transmission rod, and is used to adjust the inclination angle of the corresponding adjustable baffle when in motion. The controller is also electrically connected to each of the baffle adjusters, and is used to control the motion of each of the baffle adjusters under the control of a corresponding control signal.

[0012] In some embodiments, the control component further includes a plurality of coking monitors. The plurality of coking monitors are arranged in one-to-one correspondence with the plurality of coking positions in the boiler, and each of the coking monitors is arranged at a corresponding coking position in the boiler and is electrically connected to the controller, and is used to obtain image information and temperature information at the corresponding coking position and transmit the information to the controller. The controller is also used to determine the coking degree of the corresponding coking position based on the received image information and temperature information at the coking position, and to control the opening of the first compressed air control valve, the corresponding second compressed air control valve, the corresponding mineral powder control door, and the corresponding baffle regulator according to the coking degree, so as to spray the air-powder mixture to different areas of the corresponding coking position to remove the coke blocks at the coking position.

[0013] In some embodiments, the decoking powder supply device includes a grinder, which is used to grind the silica-alumina mineral into powder after receiving the mineral, and can adjust the particle size of the ground mineral powder. The inlet of the supply pipeline is connected to the inside of the grinder; the outlet of the delivery pipeline is connected to the inside of the grinder, and is used to deliver compressed air to the inside of the grinder. The controller is also electrically connected to the grinder, and is also used to adjust the particle size of the powder ground by the grinder according to the degree of coking.

[0014] In some embodiments, the powder is made of silicon-aluminum ore powder; in the silicon-aluminum ore powder, the mass fraction of silicon-aluminum compound is greater than or equal to 65%, and the mass fraction of aluminum oxide is greater than or equal to 15%, and the particle size R of the silicon-aluminum ore powder is 90 Satisfaction: 25% ≤ R 90 ≤30%.

[0015] Therefore, the boiler decoking system provided by the embodiment of the present invention can provide powder by providing a decoking powder supply device, and by providing a supply pipe and a conveying and pressurizing device, the inlet of the supply pipe is connected with the inside of the decoking powder supply device, and the outlet of the supply pipe is extended into the boiler and is opposite to the coking position in the boiler, and the inlet of the conveying and pressurizing device is connected with the compressed air source, and the outlet of the conveying and pressurizing device is connected with the decoking powder supply device, so that the compressed air source can convey compressed air to the decoking powder supply device through the conveying and pressurizing device, and the compressed air is mixed with the silica-alumina ore powder in the decoking powder supply device to form an air-powder mixture, and the air-powder mixture is sprayed out from the outlet of the supply pipe and sprayed toward the coking position in the boiler to remove the coke blocks at the coking position.

[0016] The inventor of the present application found that compared with the steam soot blowing method in the prior art, the air-powder mixture has higher energy after being ejected, and the use of the air-powder mixture for decoking can improve the removal effect of the coke block; further, the air-powder mixture preferably uses silicon-aluminum ore powder, because silicon-aluminum ore powder is easy to obtain, the cost is low, and the silicon-aluminum ore powder does not need to be additionally heated during decoking, so the use of silicon-aluminum ore powder for decoking has higher economy; and silicon-aluminum ore powder can increase the ash melting point of coal ash, so that the coal ash is not easy to melt and coke; silicon-aluminum ore powder also has good ion adsorption, which can adsorb and fix the alkali metals released during coal combustion (react with the alkali metal substances in the flue gas to form high melting point aluminosilicates), reducing the corrosion and coking of the alkali metals on the boiler wall. The silicon-aluminum ore powder itself has good thermal stability, can maintain a certain scouring rigidity in the high temperature environment of the furnace, and is difficult to affect the combustion in the boiler. Therefore, the boiler decoking system in the embodiment of the present invention can be used under different operating states and loads of the boiler, and can also ensure the safe and stable operation of the boiler during the decoking process.

[0017] In a second aspect, an embodiment of the present invention further provides a coal-fired boiler, comprising a boiler body and the boiler decoking system of the first aspect. A combustion space is formed inside the boiler body. An outlet of a supply pipe in the boiler decoking system extends into the boiler body and is opposite to a coking position in the boiler body, and is used to spray an air-powder mixture to the coking position in the combustion space of the boiler body to remove coke blocks at the coking position.

[0018] In a third aspect, an embodiment of the present invention further provides a method for decoking a coal-fired boiler. The method for decoking a coal-fired boiler adopts the boiler decoking system in the embodiment, and the method for decoking a coal-fired boiler comprises: introducing compressed air into the powder in the decoking powder supply device to mix the compressed air with the powder to form an air-powder mixture; and spraying the air-powder mixture to the coking position in the boiler through a supply pipe to remove the coke blocks at the coking position opposite to the outlet of the supply pipe.

[0019] In some embodiments, before removing the coke blocks at the coking location, the coal-fired boiler decoking method also includes: obtaining the coking degree at the coking location; and controlling the openings of the first compressed air control valve, the second compressed air control valve, and the mineral powder control door according to the coking degree.

[0020] In some embodiments, obtaining the degree of coking at the coking position specifically includes: obtaining image information and temperature information at the coking position; and obtaining the degree of coking at the corresponding coking position according to the image information and temperature information at the coking position.

[0021] In some embodiments, after obtaining the coking degree of the coking position, before controlling the openings of the first compressed air control valve, the second compressed air control valve, and the mineral powder control door respectively according to the coking degree, the coal-fired boiler decoking method further includes: calculating the target particle size of the powder according to the coking degree to grind the mineral into powder of the target particle size. The controlling the openings of the first compressed air control valve, the second compressed air control valve, and the mineral powder control door respectively according to the coking degree specifically includes: calculating the openings of the first compressed air control valve, the second compressed air control valve, and the mineral powder control door respectively according to the powder of the target particle size and the size of the supply pipeline.

[0022] The coal-fired boiler and the coal-fired boiler decoking method provided in the embodiments of the present invention have the same beneficial effects as the above-mentioned boiler decoking system, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : A structural diagram of a coal-fired boiler provided in an embodiment of the present invention;

[0024] Figure 2 : A top view of a coal-fired boiler provided in an embodiment of the present invention;

[0025] Figure 3 : A structural diagram of an adjustable baffle provided in an embodiment of the present invention.

[0026] Among them, 1- grinder; 2- feeder; 3- silo; 4- data collector; 5- controller; 6- compressed air source; 7- decoking nozzle; 8- high temperature convection heating surface; 11- supply pipeline; 12- first sub-pipeline; 41- coking monitor; 51- second compressed air control valve; 52- mineral powder control door; 53- first compressed air control valve; 54- control line; 61- conveying booster main pipe; 62- conveying pipeline; 63- booster pipeline; 71- adjustable baffle. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0028] Embodiment 1:

[0029] like Figure 1 As shown, an embodiment of the present invention provides a boiler decoking system, which is applied to a coal-fired boiler to remove coke inside the coal-fired boiler.

[0030] like Figure 1 As shown, the boiler decoking system includes a decoking powder supply device, a supply pipeline 11 and a conveying pressurizing device.

[0031] The decoking powder supply device is used to supply the powder.

[0032] Exemplarily, the decoking powder supply device is arranged near the boiler. The above powder is a rigid powder, and the powder can have a good flushing effect when moving at a high speed, for example, the above powder is formed by materials such as kaolin, slag or gasified slag.

[0033] In this embodiment, the powder is described by taking silicon aluminum ore powder as an example.

[0034] The inventors of the present application discovered that the components of coal ash are divided into acidic oxides and alkaline oxides, and the degree of coking mainly depends on the alkali-acid ratio in the coal ash. Usually, it is not easy to coke if the alkali-acid ratio is controlled below 0.5. That is, the higher the acidic oxide components (silicon, aluminum, titanium) in the coal ash, the more conducive to controlling coking. Among the current decoking minerals, silicon aluminum oxide has an absolute advantage in economy and can have good scouring rigidity. Compounds such as iron, calcium, and magnesium, on the one hand, have a fluxing effect in a high-temperature environment and cannot maintain good rigidity, and on the other hand, have no economic cost advantage.

[0035] Silica-alumina ore powder includes silicon oxide and aluminum oxide, which has high melting point, high hardness, good wear resistance and chemical stability, and can withstand the high temperature environment inside the boiler. Silica-alumina ore powder is easy to obtain and has low cost, which can improve the economic efficiency of the boiler decoking system.

[0036] Exemplarily, the decoking powder supply device can store silica-alumina ore powder inside, or the decoking powder supply device can directly grind silica-alumina minerals into silica-alumina ore powder.

[0037] The composition of silica-alumina ore powder is similar to that of slag. After use, the silica-alumina ore powder can be discharged together with the slag of the coal-fired boiler to reduce the impact on the environment.

[0038] Exemplarily, the silica-alumina mineral can be the slag of a coal-fired boiler. In this case, the convenience of obtaining the silica-alumina mineral can be improved, further improving the economy of the boiler decoking system, and facilitating the utilization of the slag of the coal-fired boiler and avoiding the amount of slag that ultimately needs to be processed.

[0039] The inlet of the supply pipe 11 is connected to the inside of the decoking powder supply device, and the outlet of the supply pipe 11 extends into the boiler and is opposite to the coking position in the boiler, and is used to transport the silicon-aluminum ore powder in the decoking powder supply device. The inlet of the conveying and pressurizing device is connected to the compressed air source 6, and the outlet of the conveying and pressurizing device is connected to the decoking powder supply device, and is used to transport compressed air into the decoking powder supply device, so that the compressed air is mixed with the silicon-aluminum ore powder in the decoking powder supply device to form an air-powder mixture, and the air-powder mixture is sprayed from the outlet of the supply pipe 11 to the coking position in the boiler to remove the coke blocks at the coking position.

[0040] like Figure 1 and Figure 2 As shown, a furnace is formed in the boiler, and the coking position in the boiler is usually on the furnace wall and the high-temperature convection heating surface 8 of the furnace. After coking on the furnace wall and the high-temperature convection heating surface 8 of the furnace, the thickness of the tube wall will be affected, the heat exchange time of the working medium and the flue gas will be prolonged, and the heat exchange efficiency of the boiler will be reduced.

[0041] Exemplarily, the compressed air source 6 may be an external compressed air pipeline, or an air compressor.

[0042] Exemplarily, the pressure of the compressed air provided by the compressed air source 6 is between 2 MPa and 5 MPa, which can provide sufficient air volume.

[0043] like Figure 1 As shown, after the compressed air enters the decoking powder supply device from the outlet of the conveying and boosting device, the silicon-aluminum ore powder will be blown up, and then mixed with the silicon-aluminum ore powder to form an air-powder mixture. With the continuous input of compressed air, the air-powder mixture can flow along the supply pipe 11, and spray out from the outlet of the supply pipe 11 to the coking position in the boiler. Because the silicon-aluminum ore powder has a high melting point, high hardness, good wear resistance and chemical stability, it can withstand the high temperature environment inside the boiler, and after spraying to the coking position in the boiler, it flushes the coke blocks in the coking position in the boiler to remove the coke blocks in the coking position.

[0044] Compared with the steam soot blowing method in the prior art, the silica-alumina ore powder has a larger mass, and the air-powder mixture has a higher energy after being ejected, which can improve the removal effect of the coke block; the silica-alumina ore powder is easy to obtain (the slag can be used directly), the cost is low, and the silica-alumina ore powder does not need to be additionally heated during decoking, so the use of silica-alumina ore powder for decoking has a higher economy; and the silica-alumina ore powder can increase the ash melting point of the coal ash, so that the coal ash is not easy to melt and coke; the silica-alumina ore powder also has good ion adsorption, which can adsorb and fix the alkali metals released during the coal combustion process (react with the alkali metal substances in the flue gas to form high-melting-point silicate), reducing the corrosion and coking of the alkali metals on the pot wall. The silica-alumina ore powder itself has good thermal stability, can maintain a certain scouring rigidity in the high-temperature environment of the furnace, and is difficult to affect the combustion in the boiler. Therefore, the boiler decoking system in the embodiment of the present invention can be used under different operating states of the boiler (under different loads), and the safe and stable operation of the boiler can be guaranteed during the decoking process.

[0045] Therefore, the boiler decoking system provided in the embodiment of the present invention can provide powder by providing a decoking powder supply device, and by providing a supply pipe 11 and a conveying and pressurizing device, the inlet of the supply pipe 11 is connected to the inside of the decoking powder supply device, and the outlet of the supply pipe 11 extends into the boiler and is opposite to the coking position in the boiler, and the inlet of the conveying and pressurizing device is connected to the compressed air source 6, and the outlet of the conveying and pressurizing device is connected to the decoking powder supply device, so that the compressed air source 6 can convey compressed air to the decoking powder supply device through the conveying and pressurizing device, and the compressed air is mixed with the powder in the decoking powder supply device to form an air-powder mixture, and the air-powder mixture is sprayed out from the outlet of the supply pipe 11 and sprayed toward the coking position in the boiler to remove the coke blocks at the coking position.

[0046] The inventor of the present application has found that compared with the steam soot blowing method in the prior art, the air-powder mixture has higher energy after being ejected, which can improve the removal effect of the coke block; further, the air-powder mixture preferably uses silicon-aluminum ore powder, because silicon-aluminum ore powder is easy to obtain, low cost, and silicon-aluminum ore powder does not need to be additionally heated during decoking, so the use of silicon-aluminum ore powder for decoking has higher economy; and silicon-aluminum ore powder can increase the ash melting point of coal ash, so that the coal ash is not easy to melt and coke; silicon-aluminum ore powder also has good ion adsorption, which can adsorb and fix the alkali metals released during coal combustion (react with the alkali metal substances in the flue gas to form high melting point aluminosilicates), reducing the corrosion and coking of the alkali metals on the boiler wall. Silica-aluminum ore powder itself has good thermal stability, can maintain a certain scouring rigidity in the high temperature environment of the furnace, and is difficult to affect the combustion in the boiler. Therefore, the boiler decoking system in the embodiment of the present invention can be used under different operating states of the boiler (under different loads), and can also ensure the safe and stable operation of the boiler during the decoking process.

[0047] There is also a method of using a decoking agent in the prior art. The decoking agent is usually compounded with a variety of chemical substances, mainly including an oxidant, a catalyst, a loosening agent, etc. When the decoking agent is put into the boiler, under a high temperature environment, the oxidant reacts with the carbon and other combustible substances in the coke to produce gases such as carbon dioxide; the catalyst accelerates this reaction process, causing the coke to burn and decompose to a certain extent. At the same time, the loosening agent reduces the adhesion between the coke and the heated surface, making the coke loose and porous, and falling off and discharged under the scouring of flue gas or its own gravity.

[0048] However, decoking agents are usually expensive, and there is a risk of damage to the boiler due to physical and chemical reactions during decoking. In addition, large pieces of coke and residual decoking agent that fall off are easily moved to the rear flue for discharge, affecting the environment.

[0049] The silicon-alumina ore powder in this embodiment is cheap, and will not change the physical and chemical properties of the coke block when decoking through the flushing effect, making it difficult to form large coke blocks that fall off, thereby reducing damage to the boiler. The silicon-alumina ore powder after decoking can also be discharged together with the slag, which can reduce the impact on the environment.

[0050] In some embodiments, in the silica-alumina ore powder, the mass fraction of the silica-alumina compound is greater than or equal to 65%, and the mass fraction of aluminum oxide is greater than or equal to 15%, and the particle size R 90 Satisfaction: 25% ≤ R 90 ≤30%.

[0051] For example, the mass fraction of the silicon-aluminum compound may be 65%, 75% or 85%, etc. The mass fraction of aluminum oxide may be 15%, 20% or 25%.

[0052] By adjusting the content of silicon-aluminum compounds and alumina in the silicon-aluminum ore powder, the physical and chemical properties of the silicon-aluminum ore powder, such as density, hardness, and looseness, can be adjusted, so that the physical and chemical properties of the silicon-aluminum ore powder can be convenient for transportation, difficult to react in the boiler, and the silicon-aluminum ore powder can have a better removal effect on coke blocks at the coking location.

[0053] Particle size R 90 It refers to the size of the sieve aperture when the residue (particles retained on the sieve) accounts for 90% of the total mass of the sample in particle size analysis. The unit is generally micrometer (μm).

[0054] For example, the particle size R of the silica-alumina powder is 90 It can be 25%, 27% or 30% etc.

[0055] Through the above settings, the particle size of the silicon-alumina ore powder can be controlled to ensure that the silicon-alumina ore powder has sufficient energy when sprayed to the coking position, and to avoid erosion of the furnace wall and high-temperature convection heating surface 8 of the furnace by the silicon-alumina ore powder, thereby reducing the maintenance cost of the boiler.

[0056] In some embodiments, Figure 1 and Figure 2 As shown, the outlet end of the supply pipe 11 is bifurcated to form a plurality of first sub-pipes 12, and the plurality of first sub-pipes 12 extend into the boiler and are respectively opposite to a plurality of coking positions in the boiler. Figure 2 and Figure 3 A decoking nozzle 7 is provided at the outlet of each first sub-pipeline 12, and the air-powder mixture is sprayed out by the decoking nozzle 7. An adjustable baffle 71 is provided in each decoking nozzle 7, and the inclination angle of each adjustable baffle 71 is adjustable, so as to adjust the flow direction of the air-powder mixture sprayed out by the corresponding decoking nozzle 7.

[0057] Exemplarily, the plurality of first sub-pipes 12 are arranged in one-to-one correspondence with the plurality of coking positions in the boiler, and the outlet of each first sub-pipe 12 extending into the boiler is opposite to a coking position.

[0058] Exemplarily, a plurality of decoking nozzles 7 are respectively disposed around the furnace and in the middle area of ​​the high-temperature convection heating surface 8 in the boiler. The decoking nozzles 7 are arranged according to the actual situation of the furnace. The spacing of the decoking nozzles 7 is specifically determined by the coking position in the furnace, the size of the coke blocks and the spraying distance of the air-powder mixture sprayed by the decoking nozzles 7. Ultimately, the air-powder mixture sprayed by the decoking nozzles 7 can decoke all coking positions.

[0059] Exemplarily, the spray distance of the air-powder mixture sprayed from the decoking nozzle 7 is about 1m-2m in the high-temperature radiation area of ​​the boiler (combustion center area, furnace wall, etc.), and the spray distance in the high-temperature convection heating surface 8 area is about 5m-6m.

[0060] For example, Figure 3 As shown, the opening of the decoking nozzle 7 is gradually reduced to increase the flow rate and spray distance of the air-powder mixture sprayed from the decoking nozzle 7, thereby increasing the decoking range of the air-powder mixture.

[0061] For example, Figure 3 As shown, a rotating shaft is fixed at the opening of the decoking nozzle 7, for example, the rotating shaft is welded inside the decoking nozzle 7, and an adjustable baffle 71 is rotatably arranged in the decoking nozzle 7 through the rotating shaft. When the adjustable baffle 71 is rotated, the flow direction of the air-powder mixture sprayed out of the corresponding decoking nozzle 7 can be adjusted.

[0062] Exemplarily, the extension direction of the rotating axis can be flexibly set according to the situation of the decoking position, for example, perpendicular to the length direction of the coke block at the decoking position, so that after rotating the adjustable baffle 71, the air-powder mixture sprayed by the corresponding decoking nozzle 7 can be decoked in the length direction of the coke block.

[0063] Through the above arrangement, the flow direction of the air-powder mixture sprayed from the corresponding decoking nozzle 7 can be adjusted by adjusting the adjustable baffle 71, so that the air-powder mixture can be sprayed to other areas, so that different areas can be decoked in turn, thereby increasing the decoking range of each decoking nozzle 7.

[0064] In some embodiments, Figure 1 As shown, the conveying and pressurizing device includes a conveying and pressurizing main pipe 61 and a conveying pipeline 62. The inlet of the conveying and pressurizing main pipe 61 is connected to the compressed air source 6 for conveying compressed air. The inlet of the conveying pipeline 62 is connected to the outlet of the conveying and pressurizing main pipe 61, and the outlet of the conveying pipeline 62 is connected to the inside of the decoking powder supply device for conveying compressed air to the inside of the decoking powder supply device, and conveying the air-powder mixture formed by mixing the compressed air with the silicon-alumina ore powder to the supply pipeline 11.

[0065] For example, Figure 1 As shown, the outlet of the conveying pipeline 62 is connected to the middle position inside the decoking powder supply device, so that the compressed air in the conveying pipeline 62 can be mixed with the silicon-alumina ore powder after being conveyed to the inside of the decoking powder supply device.

[0066] For example, Figure 1 As shown, the supply pipe 11 is connected to the top of the decoking powder supply device so that the evenly mixed air-powder mixture enters the supply pipe 11.

[0067] In some embodiments, Figure 1 As shown, the conveying boosting device also includes a plurality of boosting pipes 63, and the plurality of boosting pipes 63 are arranged in one-to-one correspondence with the plurality of first sub-pipes 12. The inlet of each boosting pipe 63 is connected to the outlet of the conveying boosting main pipe 61, and the outlet of each boosting pipe 63 is connected to the corresponding first sub-pipe 12, so as to convey compressed air to the corresponding first sub-pipe 12 to increase the air pressure of the air-powder mixture in the corresponding first sub-pipe 12.

[0068] The multiple boost pipes 63 are arranged in one-to-one correspondence with the multiple first sub-pipes 12, which means that the number of the boost pipes 63 and the first sub-pipes 12 are the same, and one boost pipe 63 is arranged in correspondence with one first sub-pipe 12, and the same applies below.

[0069] Exemplarily, the boost pipe 63 can adjust the pressure of the air-powder mixture in the first sub-pipeline 12 to between 0.3 MPa and 0.8 MPa.

[0070] like Figure 1 As shown, the compressed air provided by the compressed air source 6 can be delivered to each boosting pipe 63 through the delivery boosting main pipe 61, and enter each first sub-pipeline 12 through each boosting pipe 63, thereby additionally increasing the amount of compressed air in the first sub-pipeline 12, increasing the air pressure of the air-powder mixture in the first sub-pipeline 12, and increasing the flow rate and spraying distance of the air-powder mixture when it is sprayed out from the decoking nozzle 7 at the outlet of the first sub-pipeline 12, thereby increasing the energy of the air-powder mixture and thus improving the decoking effect.

[0071] In some embodiments, Figure 1 As shown, the boiler decoking system also includes a control component. The control component includes a first compressed air control valve 53, a second compressed air control valve 51 and a mineral powder control door 52. The first compressed air control valve 53 is arranged at the inlet of the conveying and boosting main pipe 61, and is used to control the opening of the conveying and boosting main pipe 61. There are multiple second compressed air control valves 51, and multiple second compressed air control valves 51 are arranged in a one-to-one correspondence with multiple boosting pipes 63. Each second compressed air control valve 51 is arranged at the outlet of the corresponding boosting pipe 63, and is used to control the opening of the corresponding boosting pipe 63. There are multiple mineral powder control doors 52, and multiple mineral powder control doors 52 are arranged in a one-to-one correspondence with multiple first sub-pipelines 12. Each mineral powder control door 52 is arranged on the corresponding first sub-pipeline 12 and is located at the front end of the outlet of the corresponding boosting pipe 63, and is used to control the opening of the corresponding first sub-pipeline 12.

[0072] Exemplarily, the first compressed air control valve 53 is an electric control valve, and the opening of the first compressed air control valve 53 can be adjusted between 0-100% (fully closed when adjusted to 0, and fully open when adjusted to 100%, the same below) to adjust the flow of compressed air passing through the first compressed air control valve 53.

[0073] The total flow rate of the compressed air source 6 delivered to the delivery and boosting main pipe 61 can be adjusted by adjusting the first compressed air control valve 53 to control the air pressure and air volume of the compressed air delivered to the delivery pipe 62 and the boosting pipe 63 .

[0074] Exemplarily, the second compressed air control valve 51 is an electric control valve, and the opening degree of the second compressed air control valve 51 can be adjusted between 0-100% to adjust the flow rate of compressed air passing through the second compressed air control valve 51 .

[0075] By adjusting the second compressed air control valve 51 , the total flow rate delivered from the boost pipe 63 to the first sub-pipeline 12 can be adjusted to control the air pressure and air volume of the compressed air delivered to the first sub-pipeline 12 and adjust the content of compressed air in the air-powder mixture in the first sub-pipeline 12 .

[0076] Exemplarily, the mineral powder control door 52 is an electric control valve, and the opening of the mineral powder control door 52 can be adjusted between 0-100% to adjust the flow of the air-powder mixture passing through the mineral powder control door 52 .

[0077] By adjusting the mineral powder control gate 52, the total amount of the air-powder mixture delivered to the first sub-pipeline 12 by the supply pipeline 11 can be adjusted to adjust the content of silicon-aluminum mineral powder in the air-powder mixture in the first sub-pipeline 12. The content of aluminum mineral powder will affect the decoking effect of the air-powder mixture.

[0078] In summary, the flow rate, air pressure, and content of silica-alumina ore powder of the air-powder mixture sprayed from the decoking nozzle 7 of the first sub-pipeline 12 can be adjusted, the flow rate and spraying distance of the air-powder mixture sprayed from the decoking nozzle 7 can be adjusted, and finally the decoking effect of the air-powder mixture can be adjusted, which helps to improve the decoking efficiency and reduce unnecessary energy consumption (for example, when the thickness of the coking position is small, the flow rate and spraying distance of the air-powder mixture can be reduced).

[0079] In some embodiments, Figure 1 As shown, the control component also includes a controller 5. The controller 5 is electrically connected to the first compressed air control valve 53, each second compressed air control valve 51, and each mineral powder control door 52, respectively, and is used to control the opening of the first compressed air control valve 53, each second compressed air control valve 51, and each mineral powder control door 52 under the control of a corresponding control signal.

[0080] For example, Figure 1 As shown, the controller 5 is electrically connected to the first compressed air control valve 53 , each second compressed air control valve 51 , and each mineral powder control door 52 through a plurality of control lines 54 .

[0081] Exemplarily, the controller 5 may be a general-purpose microprocessor that can receive control signals and issue corresponding control instructions, and can also run programs and perform calculations.

[0082] Exemplarily, the control component further includes a control panel, which is electrically connected to the controller 5 and is used to send control signals to the controller 5 .

[0083] Exemplarily, a plurality of control buttons or knobs are provided on the control panel, and corresponding control signals can be sent to the controller 5 by operating the control panel.

[0084] Alternatively, the control panel may also be a touch panel, which sends corresponding control signals to the controller 5 through touch actions.

[0085] Through the above configuration, the first compressed air control valve 53 , each second compressed air control valve 51 , and each mineral powder control door 52 can be controlled by the controller 5 .

[0086] In some embodiments, Figure 1 As shown, the control assembly further includes a plurality of baffle regulators. The plurality of baffle regulators are arranged one-to-one with the plurality of adjustable baffles 71, each baffle regulator is arranged outside the boiler, and is connected to the corresponding adjustable baffle 71 through a transmission rod, and is used to adjust the inclination angle of the corresponding adjustable baffle 71 when in motion. The controller 5 is also electrically connected to each baffle regulator, and is used to control the motion of each baffle regulator under the control of a corresponding control signal.

[0087] Exemplarily, the damper adjuster may be an electric adjuster, and a transmission rod passes through the furnace wall of the boiler.

[0088] When the inclination angle of the adjustable baffle 71 needs to be adjusted, a corresponding control signal is sent to the controller 5 through the control panel. The controller 5 sends a control instruction to the baffle adjuster to activate the baffle adjuster and drive the adjustable baffle 71 to move through the transmission rod to adjust the inclination angle of the adjustable baffle 71.

[0089] Through the above arrangement, the tilt angle of the adjustable baffle 71 can be controlled by the controller.

[0090] In some embodiments, Figure 1 and Figure 2 As shown, the control component also includes a plurality of coking monitors 41. The plurality of coking monitors 41 are arranged in one-to-one correspondence with the plurality of coking positions in the boiler, and each coking monitor 41 is arranged at a corresponding coking position in the boiler and is electrically connected to the controller 5, and is used to obtain image information and temperature information at the corresponding coking position and transmit the information to the controller 5. The controller 5 is also used to determine the coking degree of the corresponding coking position according to the received image information and temperature information at the coking position, and to control the opening of the first compressed air control valve 53, the corresponding second compressed air control valve 51, and the corresponding mineral powder control door 52 according to the coking degree, and to control the corresponding damper regulator to spray the air-powder mixture to different areas of the corresponding coking position to remove the coke blocks at the coking position.

[0091] It should be noted that the coking location in the boiler is usually located in the water-cooled wall area, and the temperature of the coking location will be higher than the temperature of other non-coking water-cooled wall areas.

[0092] Exemplarily, the coking monitor 41 is a camera that uses visible light detection and infrared detection.

[0093] The video and temperature data collected by the coking monitor 41 can also be transmitted to an external display for display, so that the coking condition of the coking position can be visualized.

[0094] Exemplarily, a heat insulating material is disposed outside each coking monitor 41 to prevent the coking monitor 41 from being damaged by high temperature.

[0095] For example, Figure 1 As shown, the image information and temperature information at the coking position acquired by the multiple coking monitors 41 are collected and summarized by the data collector 4 and then transmitted to the controller 5 .

[0096] Exemplarily, the controller 5 may determine the area, thickness, distribution position, etc. of the corresponding coking position according to the received image information and temperature information at the coking position.

[0097] For example, the controller 5 can be set (for example, by program setting) to determine that the area and thickness of the coking position reach a preset value (for example, the area exceeds 2m 2 , the thickness exceeds 20 mm), the controller 5 automatically controls the opening of the first compressed air control valve 53, the corresponding second compressed air control valve 51, the corresponding mineral powder control door 52, and the corresponding baffle regulator to start decoking the coking position.

[0098] Exemplarily, the coking monitor 41 can obtain image information and temperature information at the coking position in real time. Therefore, the controller 5 can judge the coking degree of the corresponding coking position in real time, and control the opening of the first compressed air control valve 53, the corresponding second compressed air control valve 51, and the corresponding mineral powder control door 52 in real time according to the coking degree, and control the corresponding baffle regulator action.

[0099] Exemplarily, the controller 5 can calculate the target openings of the first compressed air control valve 53, the corresponding second compressed air control valve 51, the corresponding mineral powder control door 52, and the target positions of the corresponding damper regulators in real time according to the degree of coking, and control the first compressed air control valve 53, the corresponding second compressed air control valve 51, and the corresponding mineral powder control door 52 to the target openings, and control the damper regulator to move to the target position.

[0100] Exemplarily, the control process of the controller 5 can also be set by setting a program, such as setting the opening and opening and closing time of the first compressed air control valve 53, the second compressed air control valve 51 and the mineral powder control door 52 (for example, the single opening time is about 1s-5s. After a single decoking, the controller 5 judges the degree of coking again, and then determines whether to open the first compressed air control valve 53, the second compressed air control valve 51 and the mineral powder control door 52 for decoking again), adjusting the distance and intensity of the air-powder mixture injection, and adjusting the adjustable baffle 71 to adjust the injection angle of the air-powder mixture.

[0101] Through the above configuration, the controller 5 can determine the coking degree of the corresponding coking position according to the image information and temperature information at the coking position, and automatically defocus the coking position.

[0102] In some embodiments, Figure 1 As shown, the decoking powder supply device includes a grinder 1, which is used to grind the mineral into mineral powder after receiving the mineral, and can adjust the particle size of the ground mineral powder. The inlet of the supply pipeline 11 is connected to the inside of the grinder 1. The outlet of the delivery pipeline 62 is connected to the inside of the grinder 1, and is used to deliver compressed air to the inside of the grinder 1. The controller 5 is also electrically connected to the grinder 1, and is also used to adjust the particle size of the silicon aluminum ore powder ground by the grinder 1 according to the degree of coking.

[0103] In this embodiment, when the mineral powder is silica-alumina mineral powder, the above-mentioned mineral is silica-alumina mineral.

[0104] In some examples, such as Figure 1 As shown, a silo 3 is arranged above the grinding machine 1, and a feeder 2 is arranged between the silo 3 and the grinding machine 1. The silo 3 is used to receive and store minerals, and the feeder 2 is used to transport the minerals to the grinding machine 1.

[0105] For example, when the coking degree is serious (the coking area is large and the coking thickness is thick), the controller 5 can control the grinder 1 to grind the silica-alumina mineral into a larger particle size to increase the energy of the silica-alumina ore powder spraying out of the decoking nozzle 7, thereby improving the decoking capacity of the air-powder mixture; when the coking degree is relatively light (the coking area is small and the coking thickness is thin), the controller 5 can control the grinder 1 to grind the silica-alumina mineral into a smaller particle size to reduce the energy of the silica-alumina ore powder spraying out of the decoking nozzle 7, thereby avoiding erosion of the furnace wall and the high-temperature convection heating surface 8 of the furnace by the silica-alumina ore powder, thereby avoiding increasing the maintenance cost of the boiler.

[0106] Through the above arrangement, the controller 5 can control the particle size of the silicon-alumina ore powder ground by the grinder 1 according to the coking degree, so as to adjust the energy of the silicon-alumina ore powder spraying out of the decoking nozzle 7, thereby adjusting the decoking effect on the coking position.

[0107] In summary, compared with the prior art, the beneficial results of the present invention are:

[0108] (1) The boiler decoking system provided by the embodiment of the present invention uses silicon-aluminum ore powder as the flushing medium, which has more economic advantages and decoking efficiency than the traditional decoking method. At the same time, the silicon-aluminum ore powder will not change the physical and chemical properties of the coke block, avoiding the coke block from moving to the tail flue with the change of the negative pressure in the furnace. The used silicon-aluminum minerals can be discharged together with the slag, reducing the impact on the environment.

[0109] (2) Through the cooperation of the coking monitor 41 and the controller 5, the boiler decoking system provided by the embodiment of the present invention can realize real-time intelligent monitoring of the coking degree at the coking position, and accurately control the injection conditions of the air-powder mixture (including flow rate, injection distance, injection time and injection angle, etc.) according to actual conditions, which helps to improve the decoking efficiency and reduce unnecessary energy consumption.

[0110] (3) By adjusting the grinding particle size of the grinder 1 and the injection conditions of the air-powder mixture, the boiler decoking system provided in the embodiment of the present invention can reduce the erosion problem of the furnace wall and the high-temperature convection heating surface 8 caused by the silicon-alumina ore powder, thereby reducing the boiler maintenance cost.

[0111] (4) The coking monitor 41 can collect image information and temperature information in real time and feed back the information to the controller 5 via signals, so that the decoking operation of the boiler decoking system is more timely and accurate.

[0112] (5) The coking monitor 41 uses visible light detection and infrared detection to achieve infrared visualization of the coking position, thereby improving the accuracy and real-time performance of coke detection.

[0113] Embodiment 2:

[0114] The embodiment of the present invention further provides a coal-fired boiler, which can be used in thermal power generation. The coal-fired boiler includes a boiler body and the boiler decoking system of embodiment 1. A combustion space is formed inside the boiler body. The outlet of the supply pipe 11 in the boiler decoking system extends into the boiler body and is opposite to the coking position in the boiler body, and is used to spray an air-powder mixture to the coking position in the combustion space of the boiler body to remove the coke at the coking position.

[0115] Exemplarily, the powder in the wind-powder mixture is silica-alumina powder.

[0116] Exemplarily, the boiler body uses high-alkali coal as combustion material.

[0117] High-alkali coal has the characteristics of low sulfur, low ash, moderate volatile matter and medium-to-high calorific value, but has coking characteristics.

[0118] By setting up a boiler decoking system, the coke generated by the boiler body when using high-alkali coal can be removed, thereby preventing coke blocks from affecting the safe and stable operation of the coal-fired boiler. This will enable the coal-fired boiler to use high-alkali coal, improve the fuel source of the coal-fired boiler, and expand the scope of use of high-alkali coal.

[0119] The following is an example to illustrate the decoking process and effect of a coal-fired boiler:

[0120] Example 1:

[0121] The coal-fired boilers are two 350MW supercritical unit boilers. At 70% of the rated load, coking frequently occurs on the furnace wall and high-temperature convection heating surface 8, affecting the normal operation and efficiency of the coal-fired boiler. According to the feedback from the coking monitor 41 around the furnace and the high-temperature convection heating surface 8, the coking area at the coking position is about 4m 2 , thickness is about 25mm.

[0122] Under the control of the controller 5, the grinder 1 grinds the raw material of silicon-aluminum mineral (the total amount of silicon-aluminum compounds is ≈70%, and the proportion of aluminum oxide is ≈20%) to a particle size of R 90 The controller 5 adjusts the angle of the adjustable baffle 71 to align with the coking position.

[0123] The controller 5 adjusts the opening of the first compressed air control valve 53 to 30%, and the compressed air is mixed with the silicon-aluminum ore powder ground by the grinder 1 through the delivery pipeline 62 to form an air-powder mixture, which is then sent to the supply pipeline 11 and enters the first sub-pipeline 12. The controller 5 adjusts the opening of the ore powder control door 52 to 40%, and adjusts the opening of the second compressed air control valve 51 to 30%. The air-powder mixture in the first sub-pipeline 12 is further pressurized by the compressed air input from the booster pipeline 63 and then ejected through the decoking nozzle 7, with an ejection time of 2 seconds.

[0124] After the coking monitor 41 provides feedback again, the controller 5 readjusts the angle of the adjustable baffle 71, the opening of the first compressed air control valve 53, the second compressed air control valve 51 and the mineral powder control door 52, and the air-powder mixture in the first sub-pipeline 12 is further pressurized through the booster pipe 63 and then sprayed out through the decoking nozzle 7, with a spraying time of 1 s.

[0125] After the two injections of the air-powder mixture, 85% of the coke on the furnace wall and the high-temperature convection heating surface 8 fell off, and the flushing and decoking effect was good. During the flushing process, the carbon content of the fly ash slowly increased and then decreased, fluctuating by 0.1% before and after, and finally stabilized at about 0.5%. The flushing process did not cause changes in the combustion of the coal-fired boiler. The surface wear of the furnace wall and the high-temperature convection heating surface 8 was checked, and there was no obvious change compared with before flushing.

[0126] Example 2:

[0127] In the variable load range of 30%-50% of the rated load, the coal-fired boiler has obvious coking in the middle and lower areas of the furnace wall, which cannot be removed by steam soot blowing. When the load is low, steam soot blowing will increase the probability of boiler flameout.

[0128] According to the feedback from the coking monitor 41 in the furnace radiation heat exchange area, the coking area at the coking location is about 10m 2 The thickness is about 30mm, and the decoking process adopts a decoking flushing sequence from top to bottom.

[0129] Under the control of the controller 5, the grinder 1 grinds the raw material of silicon-aluminum mineral (the total amount of silicon-aluminum compounds is ≈70%, and the proportion of aluminum oxide is ≈20%) to a particle size of R 90 The controller 5 adjusts the angle of the adjustable baffle 71 to align with the coking position.

[0130] The controller 5 adjusts the opening of the first compressed air control valve 53 to 40%, and the compressed air is mixed with the silicon-aluminum ore powder ground by the grinder 1 through the delivery pipeline 62 to form an air-powder mixture, which is then sent to the supply pipeline 11 and enters the first sub-pipeline 12. The controller 5 adjusts the opening of the ore powder control door 52 to 50%, and adjusts the opening of the second compressed air control valve 51 to 40%. The air-powder mixture in the first sub-pipeline 12 is further pressurized by the compressed air input from the booster pipeline 63 and then ejected through the decoking nozzle 7, with an ejection time of 1 second.

[0131] According to the feedback from the coking monitor 41, the coke removal situation is obtained, and the injection times and injection time are adjusted.

[0132] After the air-powder mixture was sprayed, 70% of the coke fell from the furnace wall and high-temperature convection heating surface 8, and the flushing and decoking effect was good. The flushing process did not cause changes in combustion. Through this process, the harder coke in the reduction area of ​​the water-cooled wall can be effectively removed. At the same time, by synchronously monitoring the steam-water system to adjust the temperature deviation, the heat exchange of the furnace can be effectively improved.

[0133] Embodiment 3:

[0134] The embodiment of the present invention also provides a method for decoking a coal-fired boiler. The method for decoking a coal-fired boiler adopts the boiler decoking system in Example 1. The method can remove coke blocks in the coal-fired boiler and reduce the operating cost of the coal-fired boiler.

[0135] Coal-fired boiler decoking methods include: S100-S200.

[0136] S100, introducing compressed air into the powder in the decoking powder supply device to mix the compressed air with the powder to form an air-powder mixture.

[0137] The above-mentioned powder is a rigid powder, and the powder can have a good flushing effect when the powder moves at a high speed. For example, the above-mentioned powder is a powder formed by materials such as kaolin, slag or gasified slag.

[0138] In this embodiment, the powder is described by taking silicon aluminum ore powder as an example.

[0139] Exemplarily, in the silica-alumina ore powder, the mass fraction of the silica-alumina compound is greater than or equal to 65%, and the mass fraction of the alumina is greater than or equal to 15%.

[0140] For example, the mass fraction of the silicon-aluminum compound may be 65%, 75% or 85%, etc. The mass fraction of aluminum oxide may be 15%, 20% or 25%.

[0141] Particle size R of silica-alumina ore powder 90 Satisfaction: 25% ≤ R 90 ≤30%.

[0142] Particle size R 90 It refers to the size of the sieve aperture when the residue (particles retained on the sieve) accounts for 90% of the total mass of the sample in particle size analysis. The unit is generally micrometer (μm).

[0143] For example, the particle size R of the silica-alumina powder is 90 It can be 25%, 27% or 30% etc.

[0144] Through the above settings, the particle size of the silicon-alumina ore powder can be controlled to ensure that the silicon-alumina ore powder has sufficient energy when sprayed to the coking position, and to avoid erosion of the furnace wall and high-temperature convection heating surface 8 of the furnace by the silicon-alumina ore powder, thereby reducing the maintenance cost of the boiler.

[0145] Exemplarily, the pressure of the compressed air is between 2 MPa and 5 MPa, and the formed air-powder mixture has a relatively high air pressure (for example, between 0.3 MPa and 0.8 MPa).

[0146] Compressed air can blow up the silica-alumina ore powder and then mix it with the silica-alumina ore powder to form an air-powder mixture, so that the silica-alumina ore powder can be transported in the form of an air-powder mixture, and the air-powder mixture has a higher air pressure.

[0147] S200, spraying the air-powder mixture toward the coking position in the boiler through the supply pipe 11 to remove the coking blocks at the coking position opposite to the outlet of the supply pipe 11.

[0148] Because the silica-alumina ore powder has a high melting point, high hardness, good wear resistance and chemical stability, it can withstand the high temperature environment inside the boiler. When the air-powder mixture is sprayed toward the coking position in the boiler, the air-powder mixture has a high initial velocity and energy, so that the silica-alumina ore powder in the air-powder mixture can flush the coking position in the boiler to remove the coke blocks at the coking position. Compared with the steam soot blowing method in the prior art, the air-powder mixture has higher quality, and the silica-alumina ore powder has higher energy after being sprayed out, which can improve the removal effect of the coke blocks; the silica-alumina ore powder is easy to obtain and has a low cost. The silica-alumina ore powder does not need to be additionally heated during decoking, so the use of silica-alumina ore powder for decoking has high economic efficiency; and the silica-alumina ore powder can increase the ash melting point of the coal ash, making it not easy for the coal ash to melt and coke; the silica-alumina ore powder also has good ion adsorption, which can adsorb and fix the alkali metals released during the coal combustion process (reacting with the alkali metal substances in the flue gas to form high-melting-point aluminosilicates), reducing the corrosion and coking of the alkali metals on the pot wall. Silica-alumina ore powder itself has good thermal stability, can maintain a certain scouring rigidity in the high-temperature environment of the furnace, and is difficult to affect the combustion in the boiler. Therefore, this coal-fired boiler decoking method can be used under different operating conditions of the boiler (under various loads), and can also ensure safe and stable operation of the boiler during the decoking process.

[0149] In some embodiments, Figure 1 As shown, when the boiler decoking system includes a control component, and the control component includes a first compressed air control valve 53, a second compressed air control valve 51, and a mineral powder control door 52, before removing the coke blocks at the coking position, the coal-fired boiler decoking method also includes: obtaining the coking degree at the coking position; and controlling the opening of the first compressed air control valve 53, the second compressed air control valve 51, and the mineral powder control door 52 according to the coking degree.

[0150] For example, when the coking degree at the coking position is serious (large coking area and thick thickness), refer to Figure 1, the openings of the first compressed air control valve 53, the second compressed air control valve 51, and the mineral powder control door 52 can be adjusted to be larger. At this time, the flow rate of compressed air flowing through the conveying and pressurizing main pipe 61 and the first compressed air control valve 53 increases, and the compressed air can be introduced into the decoking powder supply device through the conveying pipe 62 to introduce more compressed air, thereby increasing the content of silicon-aluminum ore powder in the air-powder mixture and the flow rate of the air-powder mixture input into the supply pipe 11; at the same time, the opening of the mineral powder control door 52 is also adjusted to be larger, so that more air-powder mixture in the supply pipe 11 can be input into each first sub-pipeline 12; the opening of the second compressed air control valve 51 is also adjusted to be larger, so that more compressed air in the conveying and pressurizing main pipe 61 can be delivered to each first sub-pipeline 12, thereby increasing the air pressure in each first sub-pipeline 12. In summary, the flow rate of the air-powder mixture in each first sub-pipeline 12, the content of silica-alumina powder in the air-powder mixture, and the air pressure of the air-powder mixture are increased, and ultimately the sprayed air-powder mixture has a higher flow rate and a larger flow rate to flush the coking position and improve the decoking effect.

[0151] Similarly, when the coking degree at the coking location is relatively light (small coking area and thin thickness), refer to Figure 1 The openings of the first compressed air control valve 53, the second compressed air control valve 51, and the mineral powder control door 52 can be adjusted to be smaller, thereby reducing the flow rate of the air-powder mixture in each first sub-pipeline 12, the content of silicon-aluminum mineral powder in the air-powder mixture, and the air pressure of the air-powder mixture, and ultimately making the sprayed air-powder mixture have a lower flow rate and a smaller flow rate, reducing the decoking effect, avoiding the air-powder mixture from eroding the furnace wall and the high-temperature convection heating surface 8 of the furnace, and reducing the maintenance cost of the boiler.

[0152] Therefore, the openings of the first compressed air control valve 53, the second compressed air control valve 51 and the mineral powder control door 52 can be flexibly adjusted according to the degree of coking at the coking position, so as to flexibly adjust the decoking effect of the air-powder mixture.

[0153] In some embodiments, the above-mentioned obtaining the degree of coking at the coking position specifically includes: obtaining image information and temperature information at the coking position; and obtaining the degree of coking at the corresponding coking position according to the image information and temperature information at the coking position.

[0154] Exemplarily, the coking degree of the coking location includes the area, location and thickness of the coke block at the coking location.

[0155] Exemplarily, the image information and temperature information at the coking position may be acquired through the coking monitor 41 . The coking monitor 41 can acquire the image information at the coking position through visible light and acquire the temperature information at the coking position through infrared light.

[0156] Exemplarily, the area size and position information of the coke at the coking position may be obtained through the image information at the coking position.

[0157] It should be noted that the coking position in the boiler is usually located in the water-cooled wall area, and the temperature of the coking position will be higher than the temperature of other water-cooled wall areas. The thickness of the coking position is different, and the temperature of the coking position is also different. Therefore, the thickness information of the coking position can be obtained by detecting the temperature of the coking position.

[0158] In some embodiments, after obtaining the coking degree of the coking position, before controlling the openings of the first compressed air control valve 53, the second compressed air control valve 51, and the mineral powder control door 52 respectively according to the coking degree, the coal-fired boiler decoking method also includes: calculating the target particle size of the powder according to the coking degree, so as to grind the mineral into powder of the target particle size.

[0159] Exemplarily, the above-mentioned mineral is a silica-alumina mineral.

[0160] For example, when the degree of coking at the coking location is serious (large coking area and thick thickness), larger silica-alumina ore powder particles are needed to ensure that the silica-alumina ore powder particles have sufficient energy to flush the coke blocks at the coking location; when the degree of coking at the coking location is relatively light (small coking area and thin thickness), smaller silica-alumina ore powder particles are used to ensure that the silica-alumina ore powder particles have sufficient energy to flush the coke blocks at the coking location.

[0161] Therefore, controlling the target particle size of the silica-alumina ore powder according to the degree of coking can achieve effective flushing of the coke blocks at the coking location.

[0162] In some embodiments, the openings of the first compressed air control valve 53, the second compressed air control valve 51, and the mineral powder control door 52 are controlled respectively according to the degree of coking, specifically including: calculating the openings of the first compressed air control valve 53, the second compressed air control valve 51, and the mineral powder control door 52 respectively according to the target particle size of the silica-alumina ore powder and the size of the supply pipeline 11.

[0163] It is understandable that when the pressure of the compressed air provided by the compressed air source 6 is constant, the larger the target particle size of the silicon-alumina ore powder, the greater the air volume required to drive the silicon-alumina ore powder to move and mix into an air-powder mixture. The larger the size of the supply pipeline 11, the more conducive it is to transport more air-powder mixture.

[0164] Exemplarily, the target particle size of the silica-alumina ore powder is larger and the size of the supply pipeline 11 is larger, and the opening of the first compressed air control valve 53 is also set to be larger (for example, 70%) to deliver more compressed air to mix with the silica-alumina ore powder through the delivery pipeline 62. The larger-sized supply pipeline 11 can also deliver more air-powder mixture to the first sub-pipeline 12. At this time, the openings of the second compressed air control valve 51 and the mineral powder control door 52 can be set to be larger (for example, both set to 70%), so that the air pressure of the air-powder mixture in the first sub-pipeline 12 is maintained higher, so that the air-powder mixture in the first sub-pipeline 12 can be sprayed out faster.

[0165] Exemplarily, the target particle size of the silica-alumina ore powder is small, the size of the supply pipeline 11 is small, and the opening of the first compressed air control valve 53 is also set to be small (for example, 30%) to deliver an appropriate amount of compressed air to mix with the silica-alumina ore powder through the delivery pipeline 62, so that the mixed air-powder mixture contains a sufficient amount of silica-alumina ore powder to avoid too little silica-alumina ore powder in the air-powder mixture and affecting the decoking effect. The smaller size of the supply pipeline 11 can make the air-powder mixture have a suitable flow rate in the supply pipeline 11, so that the air-powder mixture can be smoothly transported to the first sub-pipeline 12. At this time, the openings of the second compressed air control valve 51 and the mineral powder control door 52 can be set to be small (for example, both set to 30%), so that the air-powder mixture in the first sub-pipeline 12 has a suitable injection speed when it is sprayed, and the content of silica-alumina ore powder in the air-powder mixture is maintained.

[0166] Furthermore, when calculating the openings of the first compressed air control valve 53 , the second compressed air control valve 51 , and the mineral powder control door 52 , the pressure of the compressed air provided by the compressed air source 6 may also be referred to.

[0167] In the above manner, the openings of the first compressed air control valve 53, the second compressed air control valve 51, and the mineral powder control door 52 can be obtained, so that the first compressed air control valve 53, the second compressed air control valve 51, and the mineral powder control door 52 can be controlled according to the calculation results.

[0168] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A boiler decoking system, characterized in that: include: A decoking powder supply device for supplying powder; a supply pipe (11), wherein the inlet of the supply pipe (11) is connected to the interior of the decoking powder supply device, and the outlet of the supply pipe (11) extends into the boiler and is opposite to the coking position in the boiler, and is used to transport the powder in the decoking powder supply device; and, A conveying and boosting device, wherein the inlet of the conveying and boosting device is connected to a compressed air source (6), and the outlet of the conveying and boosting device is connected to the decoking powder supply device, and is used to convey compressed air into the decoking powder supply device, so that the compressed air is mixed with the powder in the decoking powder supply device to form an air-powder mixture, and the air-powder mixture is ejected from the outlet of the supply pipe (11) and then sprayed toward the coking position in the boiler to remove the coke blocks at the coking position.

2. The boiler decoking system according to claim 1, characterized in that: The outlet end of the supply pipeline (11) is bifurcated to form a plurality of first sub-pipelines (12), and the outlets of the plurality of first sub-pipelines (12) extend into the boiler and are respectively opposite to a plurality of coking positions in the boiler; a decoking nozzle (7) is provided at the outlet of each first sub-pipeline (12), and the air-powder mixture is sprayed out by the decoking nozzle (7); An adjustable baffle (71) is arranged inside each of the decoking nozzles (7), and the inclination angle of each of the adjustable baffles (71) is adjustable, so as to adjust the flow direction of the air-powder mixture sprayed out by the corresponding decoking nozzle (7).

3. The boiler decoking system according to claim 2, characterized in that: The conveying and pressurizing device comprises: a conveying and pressurizing main pipe (61), the inlet of which is connected to the compressed air source (6) for conveying compressed air; and, a conveying pipeline (62), wherein the inlet of the conveying pipeline (62) is connected to the outlet of the conveying booster main pipe (61), and the outlet of the conveying pipeline (62) is connected to the interior of the decoking powder supply device, and is used to convey compressed air to the interior of the decoking powder supply device, and convey the air-powder mixture formed by mixing the compressed air and the powder to the supply pipeline (11); The conveying and boosting device further comprises a plurality of boosting pipes (63), wherein the plurality of boosting pipes (63) are arranged in one-to-one correspondence with the plurality of first sub-pipes (12), the inlet of each of the boosting pipes (63) is connected to the outlet of the conveying and boosting main pipe (61), and the outlet of each of the boosting pipes (63) is connected to the corresponding first sub-pipe (12), so as to convey compressed air to the corresponding first sub-pipe (12) to increase the air pressure of the air-powder mixture in the corresponding first sub-pipe (12).

4. The boiler decoking system according to claim 3, characterized in that: Also included are control components; The control component comprises: A first compressed air control valve (53) is arranged at the inlet of the delivery booster main pipe (61) and is used to control the opening of the delivery booster main pipe (61); a second compressed air control valve (51), wherein the number of the second compressed air control valves (51) is plural, and the plural second compressed air control valves (51) are arranged in one-to-one correspondence with the plural boosting pipelines (63), and each second compressed air control valve (51) is arranged at the outlet of the corresponding boosting pipeline (63) to control the opening degree of the corresponding boosting pipeline (63); and, A mineral powder control door (52), wherein the number of the mineral powder control doors (52) is multiple, and the multiple mineral powder control doors (52) are arranged in a one-to-one correspondence with the multiple first sub-pipelines (12). Each of the mineral powder control doors (52) is arranged on the corresponding first sub-pipeline (12) and is located at the front end of the outlet of the corresponding boosting pipeline (63), and is used to control the opening of the corresponding first sub-pipeline (12).

5. The boiler decoking system according to claim 4, characterized in that: The control component also includes a controller (5); The controller (5) is electrically connected to the first compressed air control valve (53), each of the second compressed air control valves (51), and each of the mineral powder control doors (52), respectively, and is used to control the opening of the first compressed air control valve (53), each of the second compressed air control valves (51), and each of the mineral powder control doors (52) under the control of corresponding control signals.

6. The boiler decoking system according to claim 5, characterized in that: The control assembly also includes a plurality of baffle adjusters; A plurality of baffle adjusters are arranged in one-to-one correspondence with a plurality of adjustable baffles (71), each of the baffle adjusters is arranged on the outside of the boiler and connected to the corresponding adjustable baffle (71) via a transmission rod, and is used to adjust the inclination angle of the corresponding adjustable baffle (71) when in action; The controller (5) is also electrically connected to each of the baffle regulators and is used to control the action of each of the baffle regulators under the control of a corresponding control signal.

7. The boiler decoking system according to claim 6, characterized in that: The control assembly also includes a plurality of coking monitors (41); A plurality of coking monitors (41) are arranged in one-to-one correspondence with a plurality of coking positions in the boiler, and each of the coking monitors (41) is arranged at a corresponding coking position in the boiler and is electrically connected to the controller (5) to acquire image information and temperature information at the corresponding coking position and transmit the information to the controller (5); The controller (5) is also used to determine the coking degree of the corresponding coking position based on the received image information and temperature information at the coking position, and control the opening of the first compressed air control valve (53), the corresponding second compressed air control valve (51), and the corresponding mineral powder control door (52) according to the coking degree, and control the action of the corresponding baffle regulator to spray the air-powder mixture to different areas of the corresponding coking position to remove the coke blocks at the coking position.

8. The boiler decoking system according to claim 7, characterized in that: The decoking powder supply device comprises a grinder (1), which is used to grind the mineral into powder after receiving the mineral, and can adjust the particle size of the ground mineral powder; The inlet of the supply pipe (11) is in communication with the interior of the grinder (1); the outlet of the delivery pipe (62) is in communication with the interior of the grinder (1) for delivering compressed air to the interior of the grinder (1); The controller is also electrically connected to the grinder (1) and is also used to adjust the particle size of the powder ground by the grinder (1) according to the degree of coking.

9. The boiler decoking system according to any one of claims 1 to 8, characterized in that: The powder is silica-alumina ore powder; In the silicon-aluminum ore powder, the mass fraction of silicon-aluminum compounds is greater than or equal to 65%, and the mass fraction of aluminum oxide is greater than or equal to 15%, and the particle size of the silicon-aluminum ore powder is R 90 Satisfaction: 25% ≤ R 90 ≤30%.

10. A coal-fired boiler, characterized in that: include: The boiler body, the interior of which forms a combustion space; and, The boiler decoking system according to any one of claims 1 to 9, wherein the outlet of the supply pipe (11) in the boiler decoking system extends into the boiler body and is opposite to the coking position in the boiler body, and is used to spray an air-powder mixture toward the coking position in the combustion space of the boiler body to remove coke blocks at the coking position.

11. A method for decoking a coal-fired boiler, characterized in that: Using the boiler decoking system according to any one of claims 1 to 9, the method comprises: Passing compressed air into the powder in the decoking powder supply device to mix the compressed air with the powder to form an air-powder mixture; The air-powder mixture is sprayed toward the coking position in the boiler through the supply pipe (11) to remove the coking blocks at the coking position opposite to the outlet of the supply pipe (11).

12. The method for decoking a coal-fired boiler according to claim 11, characterized in that: Using the boiler decoking system as claimed in claim 4; Before removing the coke blocks at the coking position, the coal-fired boiler decoking method further comprises: Obtain the coking degree of the coking position; The openings of the first compressed air control valve (53), the second compressed air control valve (51) and the mineral powder control door (52) are controlled respectively according to the coking degree.

13. The method for decoking a coal-fired boiler according to claim 12, characterized in that: The obtaining of the coking degree of the coking position specifically includes: Acquire image information and temperature information at the coking position; The coking degree of the corresponding coking position is obtained according to the image information and temperature information at the coking position.

14. The method for decoking a coal-fired boiler according to claim 13, characterized in that: After obtaining the coking degree of the coking position, before respectively controlling the openings of the first compressed air control valve (53), the second compressed air control valve (51), and the mineral powder control door (52) according to the coking degree, the method further includes: Calculating the target particle size of the powder according to the coking degree to grind the mineral into powder of the target particle size; The steps of controlling the openings of the first compressed air control valve (53), the second compressed air control valve (51), and the mineral powder control door (52) respectively according to the coking degree specifically include: According to the target particle size of the powder and the size of the supply pipeline (11), the openings of the first compressed air control valve (53), the second compressed air control valve (51) and the mineral powder control door (52) are calculated respectively.

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