Multi-tube through-flow boiler and method for operating same
By using nozzles to inject steam in a multi-tube flow boiler, the large-scale generation and adhesion of residual ash in the combustion chamber caused by regenerated oil combustion is solved, and the effect of reducing the cleaning frequency and improving operation efficiency is achieved.
Patent Information
- Application Number
- CN202280101408.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-10-26
- Publication Date
- 2025-06-20
AI Technical Summary
In a multi-tube flow boiler using regenerated oil as fuel, residual ash in the combustion chamber is generated in large quantities, resulting in an increase in the cleaning frequency and the residual ash attached to the surface of the water pipe is difficult to completely remove.
In the operation of a multi-tube type flow boiler, the steam consumed obtained by intermittently ejecting the feedback through multiple nozzles, and the injection time and the injection angle are controlled to suppress the adhesion of residual ash to the surface of the water pipe.
It effectively suppresses the adhesion of residual ash to the surface of the water pipe, reduces the cleaning frequency, improves the operation efficiency of the boiler, and prevents the reduction of the surface temperature of the water pipe.
Smart Images
Figure CN120187985A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a multi-tube once-through boiler that generates steam by heating a plurality of water pipes, and particularly to a structure and an operation method for reducing the generation of residual ash adhering to the combustion chamber in a multi-tube once-through boiler that can use recycled oil as fuel. Background Art
[0002] For example, as disclosed in Patent Document 1 Figure 12 and Figure 13 As shown, the multi-tube once-through boiler is configured such that a plurality of water pipes are arranged vertically in a cylindrical combustion cylinder with upper and lower bottoms, and the annular upper header 1 and the lower header 2 are connected by two rows of water pipes, namely the inner water pipe row 3 and the outer water pipe row 4. The space between adjacent inner water pipe rows 3 and adjacent outer water pipe rows 4 is closed (closed fin 8), and a part of the space between the water pipes in the inner water pipe row 3 is opened (inner flue opening 5), thereby forming a combustion gas passage 7 between the inner water pipe row 3 and the outer water pipe row 4, and water is supplied to each water pipe from the lower header 2.
[0003] In the above structure, the following structure is formed: fuel is supplied to a burner 10 provided in the combustion cylinder and burned, thereby generating combustion gas in the combustion chamber 9. The combustion gas is supplied to the outside of the plurality of water pipes from the combustion gas passage 7 to heat and evaporate the boiler water in the water pipes, and the consumed steam is taken out from the upper header 1. In addition, the combustion exhaust gas passes through the combustion gas passage 7 and the outer flue opening 6 and is discharged from the flue 12 as the combustion exhaust gas with reduced temperature.
[0004] The peripheral portions of the upper header 1 and the lower header 2 are covered with a refractory material 13, and the entire combustion cylinder is covered with a heat insulating material 14.
[0005] However, in the above multi-tube once-through boiler, since the combustion chamber is sealed and it is difficult to clean the inside of the combustion cylinder, there is a problem that the fuel of the combustion gas burned by the burner is limited, and recycled oil composed of waste oil that easily generates residual ash cannot be used.
[0006] Therefore, the present inventor proposed a multi-tube once-through boiler of Patent Document 2 having a structure capable of using recycled oil (waste oil) as fuel for generating combustion gas for consumed steam.
[0007] According to this structure, by forming the combustion chamber into a cylindrical shape extending in the horizontal direction and forming a door (cover) on one end side facing the combustion chamber, it is possible to face the inside by opening and closing the door (cover), and it is easy to clean the combustion chamber, so that recycled oil (waste oil) can be used as fuel for combustion gas (refer to Patent Document 2).
[0008] Prior Art Documents
[0009] Patent Document
[0010] Patent Document 1: Japanese Patent Publication No. 2914647
[0011] Patent Document 2: Japanese Patent Publication No. 7099864 Summary of the Invention
[0012] Problems to be Solved by the Invention
[0013] However, in the proposed multi-tubular once-through boiler, although the inside of the combustion chamber can be cleaned by opening and closing the door (cover body), a large amount of residual ash is unexpectedly generated due to the use of recycled oil (waste oil), and accordingly, the cleaning frequency increases, resulting in a complicated cleaning operation. In particular, the cleaning of opening and closing the door (cover body) is carried out after the operation of the multi-tubular once-through boiler stops. Therefore, there is a problem that it takes time to completely remove the residual ash firmly attached to the inside of the combustion chamber and around the water pipes.
[0014] The present invention has been completed in view of the above actual situation, and its object is to provide a structure of a multi-tubular once-through boiler that can suppress the attachment of residual ash in the combustion chamber to the surface of the water pipes when using recycled oil (waste oil) as the combustion gas for generating consumption steam.
[0015] To achieve the above object, the multi-tubular once-through boiler (100) of the present invention has a combustion chamber (9) supplied with combustion gas from a burner (10) provided on one end side. A water pipe row composed of a plurality of water pipes is provided in the combustion chamber (9). The boiler water supplied into the water pipes is heated and evaporated by the combustion gas to extract consumption steam. The multi-tubular once-through boiler is characterized in that it uses recycled oil as fuel and has a plurality of nozzles arranged to spray steam to the surface side of the water pipe row and a spray control device for controlling the spray time of the steam from the nozzles. Thus, steam is intermittently sprayed during the operation of the multi-tubular once-through boiler to suppress the attachment of residual ash generated by the combustion of the recycled oil to the surface side of the water pipe row.
[0016] It is characterized in that the multi-tubular once-through boiler has a spray control device (85) for controlling the spray time of the steam sprayed from the nozzles, and steam is intermittently sprayed during the operation of the multi-tubular once-through boiler.
[0017] It is characterized in that the steam sprayed from the nozzles is used by feedback of the consumption steam obtained from the multi-tubular once-through boiler (100).
[0018] It is characterized in that the steam is supplied by branching the consumption steam taken out from the multi-tubular once-through boiler.
[0019] It is characterized in that a first nozzle row composed of a plurality of nozzles (50) is arranged at a position facing the water pipe row from the partition wall (30), and the partition wall (30) is provided in the combustion chamber (9) so that the combustion gas from the burner (10) collides and flows backward.
[0020] It is characterized in that the water pipe row is composed of an inner water pipe row (3) and an outer water pipe row (4).
[0021] A second nozzle row composed of a plurality of nozzles (60) is arranged at a position facing the gap between the inner water pipe row (3) and the outer water pipe row (4) from the inner surface side of the closing plate (40a) of the combustion chamber (9) provided on the burner (10) side.
[0022] It is characterized in that a third nozzle row composed of a plurality of nozzles (70) is arranged at a position facing the gap between the inner water pipe row (3) and the outer water pipe row (4) from the inner surface side of the closing plate (40b) behind the partition wall (30) provided on the side opposite to the burner (10).
[0023] It is characterized in that the injection angle of steam in each nozzle (50) of the first nozzle row is 100 degrees to 115 degrees.
[0024] And it is characterized in that the injection angle of steam in each nozzle (60, 70) of the second nozzle row and the third nozzle is 10 degrees to 20 degrees.
[0025] It is characterized in that this multi-tubular once-through boiler is provided with a flue (12) communicating with the combustion chamber (9), and a cyclone device (90) is connected to the flue (12).
[0026] It is characterized in that a bag filter (92) is connected to the outlet of the combustion gas in the cyclone device (90) via a cooling device (91) on the flue (12).
[0027] It is characterized in that a single bag filter (92) is connected to the cyclone device (90) and the cooling device (91).
[0028] Further, in a multi-tubular once-through boiler, both ends of each of a plurality of water tubes are communicated with each other, and boiler water is supplied to each water tube. On the other hand, a combustion chamber is formed inside each water tube, and combustion gas from the combustion chamber is supplied to the surface side of the plurality of water tubes to heat and evaporate the boiler water in the water tubes, and the consumed steam is taken out. It is characterized in that the multi-tubular once-through boiler uses recycled oil as fuel. The multi-tubular once-through boiler is formed with a door (cover body 22) on one end side facing the combustion chamber (9), and a burner (10) for supplying combustion gas to the combustion chamber (9) is provided on the outer side surface of the door (cover body 22). The combustion chamber (9) is in a cylindrical shape extending in the horizontal direction. Each of the water tubes is in an arc shape arranged on the left and right sides of the combustion chamber (9). For the water tube row arranged on the left side of the combustion chamber (9), it is connected by a linear left upper header (1L) provided at the upper end and a linear left lower header (2L) provided at the lower end respectively. For the water tube row arranged on the right side of the combustion chamber (9), it is connected by a linear right upper header (1R) provided at the upper end and a linear right lower header (1R) provided at the lower end respectively. The water tube row is composed of an inner water tube row (3) and an outer water tube row (4). Each water tube of the outer water tube row (4) is arranged between each water tube of the inner water tube row (3). Each water tube of the inner water tube rows (3) on the left and right is connected by a closing fin (8). Each water tube of the outer water tube rows (4) on the left and right is connected by a closing fin (8). A partition wall (30) is provided near the end of the inner water tube row (3) at the injection destination of the combustion gas to divide the combustion chamber (9), so that the supplied combustion gas all flows backward after hitting the partition wall (30) and returns to the door (cover body 22) side. And, an inner smoke passage opening (5) is formed between the end water tube of the inner water tube row (3) on the door (cover body 22) side of the combustion chamber (9) and the combustion chamber wall on the door (cover body 22) side. Cut portions (5A) are formed only on the closing fins (8) connecting the water tubes of the inner water tube row (3) and having a number of 10% to 20% of the total number of water tubes starting from the door (cover body 22) side. On the other hand, on the combustion chamber (9) side of the partition wall (30), a plurality of nozzles (50) for injecting steam are arranged in a manner of being arranged along the vicinity of the inner water tube row (3).
[0029] It is characterized in that a flue (12) communicating with the combustion chamber (9) is arranged on the upper surface of the combustion chamber (9) on the side opposite to the door side, and upper cut portions (41) are formed on a plurality of closing fins (8) of the outer water tube row (4) at the position facing the opening of the flue (12).
[0030] It is characterized in that a plurality of nozzles (60) for injecting steam into the gap are arranged at a position facing the gap between the inner water pipe row (3) and the outer water pipe row (4) in the door side of the combustion chamber (9).
[0031] It is characterized in that a plurality of nozzles (70) for injecting steam into the gap are arranged at a position facing the gap between the inner water pipe row (3) and the outer water pipe row (4) on the inner surface side of the closing plate (40b) provided on the side opposite to the door side of the combustion chamber (9).
[0032] In the operation method of a multi-tube once-through boiler, the multi-tube once-through boiler connects the two end sides of each of a plurality of water pipes respectively and supplies boiler water to each water pipe. On the other hand, a combustion chamber is formed inside each water pipe, and combustion gas from a burner provided at one end side of the combustion chamber is supplied to the surface side of a water pipe row composed of a plurality of water pipes to heat and evaporate the boiler water in the water pipe, and the consumed steam is taken out. It is characterized in that recycled oil is used as fuel, and steam is intermittently injected from the plurality of nozzles arranged during the operation of the multi-tube once-through boiler to the surface side of the water pipe row, thereby suppressing the adhesion of residual ash generated due to the combustion of recycled oil to the surface side of the water pipe row.
[0033] It is characterized in that the intermittent injection of steam in the operation method of the multi-tube once-through boiler is to inject for 5 to 15 seconds every 1 to 2 hours.
[0034] Advantages of the Invention
[0035] According to the present invention, in a multi-tube once-through boiler using recycled oil as combustion fuel, by intermittently injecting steam from a plurality of nozzles (50, 60, 70) during the operation of the multi-tube once-through boiler, the adhesion of residual ash generated due to the combustion of recycled oil to the surface side of the water pipe row (3, 4) can be suppressed.
[0036] By intermittently injecting steam during the operation of the multi-tube once-through boiler, the temperature drop of the water pipe row (3, 4) can be suppressed.
[0037] By feeding back the consumed steam obtained from the multi-tube once-through boiler (100), steam can be injected from the nozzles (50, 60, 70) without adding a steam generator.
[0038] By branching (84) the consumed steam obtained from the multi-tube once-through boiler (100), the consumed steam can be fed back for use.
[0039] By arranging the first nozzle row (nozzle 50) at a position facing the water pipe row from the partition wall (30), the generation of residual ash adhering to the water pipe row (inner water pipe row 3) when the combustion gas from the burner (10) collides and flows backward can be suppressed.
[0040] In the operation of a multi-tubular once-through boiler using recycled oil as a combustion fuel, by injecting steam from a plurality of nozzles (60) provided on the door side of the combustion chamber (9), generation of residual ash adhering to the gap between the inner water tube row (3) and the outer water tube row (4) is suppressed, and accumulation of combustion gas on the door side can be prevented to make the flow smooth.
[0041] In the operation of a multi-tubular once-through boiler (100) using recycled oil as a combustion fuel, by injecting steam from a plurality of nozzles (70) provided on the side opposite to the door side of the combustion chamber (9), generation of residual ash adhering to the gap between the inner water tube row (3) and the outer water tube row (4) can be suppressed.
[0042] By expanding the injection angle of the steam in the nozzle (50) to 100 degrees to 115 degrees, the injected steam easily hits the periphery of the water tube rows (3, 4), and generation of residual ash adhering to this part can be effectively suppressed.
[0043] By narrowing the injection angle of the steam in the nozzles (60, 70) to 10 degrees to 20 degrees, the injected steam is injected in a straight line direction and easily enters the gap between the inner water tube row (3) and the outer water tube row (4), and generation of residual ash adhering to this part can be effectively suppressed.
[0044] By connecting a cyclone device (90) to the flue (12), solid components (powder) can be removed from the combustion gas.
[0045] By connecting a bag filter (92) to the outlet of the combustion gas via a cooling device (91), powder in the combustion gas can be reliably removed in the bag filter (92).
[0046] By connecting a plurality of cyclone devices (90) and a cooling device (91) to one bag filter (92), the usage efficiency of the bag filter (92) can be improved and the structure can be simplified.
[0047] In the operation of a multi-tubular once-through boiler (100) using recycled oil as a combustion fuel, by injecting steam from a plurality of nozzles (50), generation of residual ash adhering to the inner water tube row (3) can be suppressed.
[0048] By forming an upper cut portion (41) on a plurality of closing fins (8) of the outer water tube row (4), combustion gas in the combustion chamber (9) can flow out from the upper cut portion (41) to the outside of the outer water tube row (4) and be guided to the flue (12). Description of the Drawings
[0049] Figure 1It is a side view explanatory drawing of a multi-tube once-through boiler showing one embodiment of the present invention.
[0050] Figure 2 It is a front view explanatory drawing of a multi-tube once-through boiler showing one embodiment of the present invention.
[0051] Figure 3 It is a front view explanatory drawing of the inner water tube row and the outer water tube row.
[0052] Figure 4 It is a partial cross-sectional explanatory drawing showing the connection structure of the upper header, the inner water tubes, and the outer water tubes.
[0053] Figure 5 It is a side view explanatory drawing of the inner water tube row and the outer water tube row.
[0054] Figure 6 It is a top view perspective explanatory drawing for explaining the structure inside the main body of the multi-tube once-through boiler.
[0055] Figure 7 It is a side view perspective explanatory drawing for explaining the structure inside the main body of the multi-tube once-through boiler.
[0056] Figure 8 It is for explaining the nozzle installation location Figure 6 VIII-VIII sectional explanatory drawing in
[0057] Figure 9 It is a perspective explanatory drawing of the main body viewed from the cover side for explaining the nozzle installation location.
[0058] Figure 10 It is a perspective explanatory drawing of the main body viewed from the combustion chamber side for explaining the nozzle installation location.
[0059] Figure 11 It is a system structure drawing for explaining the flow of combustion exhaust gas in the case of using multiple multi-tube once-through boilers.
[0060] Figure 12 It is a structure explanatory drawing showing the schematic structure of an existing multi-tube once-through boiler.
[0061] Figure 13 It is Figure 12 A-A sectional explanatory drawing of Detailed implementation mode
[0062] An embodiment of the multi-tube once-through boiler of the present invention will be described with reference to the accompanying drawings.
[0063] Figure 1 And Figure 2The external appearance of the multi-tubular once-through boiler 100 is shown. Relative to the hinge portion 21 mounted on the bottomed cylindrical main body 20 arranged horizontally and having both ends closed by the closing plate 40a and the closing plate 40b, a cover body 22 that serves as a door for opening and closing the front side of the main body 20 is rotatably mounted. A burner 10 is provided on the outer side surface of the cover body 22. By supplying fuel to the burner 10 and burning it (about 1500 °C), combustion gas is generated in the combustion chamber 9 sandwiched between the closing plate 40a on the cover body 22 side and the closing plate 40b inside the main body 20. The peripheral portion of the burner 10 on the combustion chamber 9 side is covered with a refractory material 13.
[0064] The combustion gas generated in the combustion chamber 9 of the main body 20 heats a plurality of water pipes provided inside the main body 20 from the surface side and is discharged as combustion exhaust gas from a flue 12 provided above the main body 20.
[0065] Water is supplied to the plurality of water pipes, and the periphery of each water pipe is heated by the combustion gas generated in the combustion chamber 9 to generate steam. The steam is discharged to the outside as consumption steam from a piping line 81 via a steam-water separator 80 for removing larger water droplets in the steam. A pressure gauge 82 for measuring the steam pressure and a safety valve 83 for releasing steam when the pressure rises are installed in the steam-water separator 80.
[0066] Regarding the multi-tubular once-through boiler 100 of the present invention, as the combustion gas for generating consumption steam, when only using recycled oil as fuel, in-depth research has been repeatedly carried out. As a result, it has been found that injecting steam into the combustion chamber during operation is beneficial to suppressing the adhesion of residual ash in the combustion chamber, and a structure for this has been proposed.
[0067] Recycled oil includes various used mineral-based waste oils such as engine oil, waste cooking oils represented by used tempura oil, waste animal and vegetable oils mainly obtained from animal fats, and oil collected from waste water containing oils discharged from kitchens such as restaurants by an oil collector (oil trap) and stored.
[0068] Hereinafter, with reference to Figures 3 to 6 The internal structure of the main body 20 of the multi-tubular once-through boiler 100 will be described.
[0069] A bottomed cylindrical combustion chamber 9 extending in the horizontal direction is formed in the center of the main body 20, and a plurality of arc-shaped water pipes are arranged so as to surround the periphery inside the combustion chamber 9.
[0070] The water pipe group arranged on the left inner side of the combustion chamber 9 in the plurality of arc-shaped water pipes is defined as the inner water pipe row 3L, and the upper ends are connected by the linear left upper header 1L, and the lower ends are connected by the linear left lower header 2L. Similarly, the water pipe group arranged on the right inner side of the combustion chamber 9 is defined as the inner water pipe row 3R, and the upper ends are connected by the linear right upper header 1R, and the lower ends are connected by the linear right lower header 2R. Moreover, the water pipes constituting the left and right inner water pipe rows 3L and 3R are connected by the closing fins 8.
[0071] Water pipes are arranged outside the inner water pipe row 3 and between the respective water pipes of the inner water pipe row 3, and these water pipe groups constitute the outer water pipe row 4. The outer water pipe row 4 is arranged outside the left and right inner water pipe rows 3 respectively. Similar to the left and right inner water pipe rows 3, the upper ends of the water pipe group on the left side are connected to the left upper header 1L, and the lower ends are connected to the left lower header 2L. The upper ends of the water pipe group on the right side are connected to the right upper header 1R, and the lower ends are connected to the right lower header 2R. Moreover, between the respective water pipes constituting the left and right outer water pipe rows 4, similar to the inner water pipe row 3, they are connected by the closing fins 8.
[0072] Moreover, the combustion chamber 9 is partitioned by providing a partition wall 30 made of a refractory material 13 near the end of the inner water pipe row 3, which is the injection destination of the combustion gas inside the main body 20, and the combustion gas ejected from the burner 10 is configured to all flow backward after colliding with the partition wall 30. On the combustion chamber 9 side of the partition wall 30, a refractory material 13 with sufficient thickness is arranged so that it will not be deformed even if high-temperature combustion gas collides. For the closing plate 40b, in order to prevent deformation, a heat insulating material 14 is also arranged on its inner part.
[0073] On the combustion gas supply side (the cover 22 side), an inner smoke passage port 5 is formed between the inner side wall of the cover 22 and the end water pipe, and a cutout portion (inner smoke passage port 5A) is formed on the closing fin 8 that connects the water pipes of the inner water pipe row 3. That is, as Figure 6 shown, cutout portions (the slanted portions in Figure 5 ) are respectively formed on the three closing fins 8 from the cover 22 side. The cutout area of this cutout portion is formed by openings in three stages that are the widest on the cover 22 side. This is because, by increasing the cutout portion (refer to Figure 5 ) at the position of the outlet of the combustion gas closer to the burner 10, the combustion gas flowing backward after colliding with the partition wall 30 easily returns to the vicinity of the cover 22 side.
[0074] In this example, cut portions (diagonal line portions) are formed only on three closing fins 8 with respect to 19 water pipes, but the number of closing fins 8 on which the cut portions are formed is preferably such that cut portions are formed at about 10% to 20% with respect to the total number of water pipes. That is, in this example, two to three cut portions are formed with respect to 19 water pipes so that there is no resistance to the flow of combustion gas and the combustion gas reliably flows backward.
[0075] Next, with reference to Figures 6 to 10 the structure of the nozzle row provided in the combustion chamber 9, which is a characteristic part of the present invention, will be described.
[0076] On the inner surface side of the partition wall 30 provided on the side opposite to the gate side of the combustion chamber 9, a plurality of nozzles 50 (first nozzle group) for injecting steam are annularly arranged at positions along the inner side of the inner water pipe row 3.
[0077] Specifically, as shown in Figure 6 and Figure 8 a plurality of nozzles 50 with injection ports facing the combustion chamber 9 are provided on a circular pipe 51 arranged along the inner side of the inner water pipe row 3 in the combustion chamber 9.
[0078] Moreover, at positions on the lid body 22 side of the combustion chamber 9 facing the gap between the inner water pipe row 3 and the outer water pipe row 4, a plurality of nozzles 60 (second nozzle group) for injecting steam into the gap are annularly arranged along the gap between the water pipe rows.
[0079] Specifically, as shown in Figure 6 , Figure 9 and Figure 10 a pair of semi-circular pipes 61 are provided in the combustion chamber 9, and steam is supplied to each semi-circular pipe 61 from the outside via a pipe 62, whereby steam is supplied along the semi-circular pipes 61 and steam is injected from a plurality of nozzles 60 provided on the semi-circular pipes 61.
[0080] In addition, on the partition wall 30 side of the combustion chamber 9, at positions facing the gap between the inner water pipe row 3 and the outer water pipe row 4, a plurality of nozzles 70 (third nozzle group) for injecting steam into the gap are annularly arranged along the gap between the water pipe rows.
[0081] Specifically, as shown in Figure 6 and Figure 8 a plurality of nozzles 70 are provided on a circular pipe 71 arranged between the inner water pipe row 3 and the outer water pipe row 4 in the combustion chamber 9.
[0082] As shown in Figure 2 and Figure 6As shown, the exhaust steam from the multi-tubular once-through boiler 100 is branched at 84 and supplied to the plurality of nozzles 50, 60, 70 through the circular pipe 51, the semi-circular pipe 61, and the circular pipe 71 from the pipes 52, 62, 72 via the injection control device 85, respectively.
[0083] Through the branch 84, a part of the exhaust steam discharged from the multi-tubular once-through boiler 100 is fed back and can be used as the injection steam from each of the nozzles 50, 60, 70.
[0084] Moreover, in the injection control device 85, the injection time, injection amount, and injection pressure of the steam are controlled so that the steam is intermittently injected from the front ends of the nozzles 50, 60, 70 at a pressure of 0.4 MPa to 0.8 MPa at intervals of 1 hour to 2 hours for 5 seconds to 15 seconds.
[0085] When the multi-tubular once-through boiler 100 that obtains exhaust steam at a pressure of 0.49 MPa to 0.98 MPa is in operation, the temperature in the combustion chamber 9 reaches 900°C to 1000°C. Therefore, if steam at about 150°C to 175°C is injected from each nozzle, the temperature of the water pipes is reduced. However, by intermittently injecting the steam, the reduction in the surface temperature of the water pipes can be suppressed.
[0086] In the above example, regarding the steam supplied to each nozzle, the exhaust steam discharged from the multi-tubular once-through boiler 100 is branched at 84 and adjusted by the injection control device 85 for use. However, instead of using the exhaust steam of the multi-tubular once-through boiler 100, steam supplied from other pipelines can also be used. For example, the steam supplied from other pipelines can also be controlled for the supply time and pressure through a flow regulator and a pressure regulator and intermittently injected into the combustion chamber 9.
[0087] Injecting steam from each nozzle is to blow off the residual ash by injecting steam with mass and suppress the adhesion to the surroundings of the water pipes constituting the water pipe rows 3 and 4. Moreover, by using high-temperature steam, when the steam comes into contact with the water pipes, the occurrence of damage to the water pipes in the combustion chamber 9 filled with combustion gas and having a high temperature (900 - 1000°C) is also prevented.
[0088] Moreover, for the nozzle holes in each of the nozzles 50 in the first nozzle row, nozzle holes with an injection angle of 100 degrees to 115 degrees are selected. This is because, by setting it to a wide angle of about 110 degrees, the injection range is expanded and the injection is reliably made to the inner wall surface of the inner water pipe 3 to suppress the adhesion of residual ash.
[0089] In each of the nozzles 60 and 70 of the second nozzle row and the third nozzle row, nozzle holes with a spray angle of 10 degrees to 20 degrees are selected. By narrowing the spray angle to make the steam spray in a straight line direction, the steam can easily enter the gap between the inner water pipe row 3 and the outer water pipe row 4.
[0090] Moreover, in order to prevent the attachment of residual ash around the water pipes, the pressure of the steam to be sprayed is preferably about 0.4 MPa to 0.8 MPa.
[0091] According to the above structure, by spraying steam from a plurality of nozzles 50, 60, and 70 during the operation of the multi-tubular once-through boiler 100, the generation of residual ash adhering to the surface of the inner water pipe row 3 in the combustion chamber can be suppressed by the first nozzle group, and the generation of residual ash adhering to the gap portion between the inner water pipe row 3 and the outer water pipe row 4 can be suppressed by the second nozzle group and the third nozzle group.
[0092] Moreover, by arranging a plurality of nozzles 60 (the second nozzle group) on the door side, when the flow of the combustion gas flowing reversely in the combustion chamber 9 flows from the door (cover body 21) side to the closing plate 40b side in the gap between the inner water pipe row 3 and the outer water pipe row 4, the flow of the combustion gas can be made smooth by spraying steam at the portion where the flow stagnates at the notch portion 5A.
[0093] A flue 12 for discharging combustion exhaust gas communicating with the combustion chamber 9 is arranged on the upper surface of the combustion chamber 9 on the side opposite to the door side. And, on a plurality of closing fins 8 (three water pipes in the example of the figure) of the outer water pipe row 4 at the position facing the opening portion 12a of the flue 12, upper notch portions 41 corresponding to the upper semi-circle are formed.
[0094] Due to the existence of the plurality of upper notch portions 41, on the closing plate 40b side, the combustion exhaust gas can flow out from the gap between the inner water pipe row 3 and the outer water pipe row 4 to the outside of the outer water pipe row 4 via the upper notch portions 41.
[0095] In addition, the three upper notch portions 41 are formed such that the opening area becomes larger as it approaches the dividing wall 30. This is to make the flow of the combustion gas reach the inner side as much as possible, increase the contact area with the water pipe row, and improve the heat exchange efficiency with the combustion gas.
[0096] A cyclone device 90 for separating powder (residual ash) from the combustion exhaust gas is connected above the flue 12. The cyclone device 90 is a powder separator that separates the powdery residual ash mixed with the gas by centrifugal separation, and a device having a general structure for separating the gas and the powder is used.
[0097] Water supply ports 23 are respectively provided on the lower surfaces of the left lower header 2L and the right lower header 2R, and steam discharge ports 24 are respectively provided on the upper surfaces of the left upper header 1L and the right upper header 1R.
[0098] According to the above structure, if water is supplied from the respective water supply ports 23 of the left lower header 2L and the right lower header 2R, boiler water is supplied to each of the plurality of water pipes arranged in an arc shape. And if combustion gas is supplied from the burner 10 to the combustion chamber 9, the combustion gas from the combustion chamber 9 contacts the inner side surfaces (the surfaces on the combustion chamber 9 side) of the water pipes in the inner water pipe row 3, heating the boiler water in the water pipes.
[0099] The combustion gas is rebounded by the partition wall 30 provided at the end of the combustion chamber 9 and returns toward the cover body 22. However, as Figure 6 shown, the combustion gas guided from the inner flue opening 5 and the cutout portion (inner flue opening 5A) to the combustion gas passage 7 between the inner water pipe row 3 and the outer water pipe row 4 contacts the inner side surfaces of the inner water pipe row 3 and the outer water pipe row 4, heating the boiler water in the water pipes.
[0100] The boiler water in the water pipes of the inner water pipe row 3 and the outer water pipe row 4 is heated to become steam, and is taken out from the steam discharge ports 24 provided on the left upper header 1L and the right upper header 1R via the steam-water separator 80, the pipeline 81, and the branch 84, and is consumed at a desired supply location.
[0101] The combustion gas is cooled by heating the boiler water in the water pipes, and is discharged to the outside after being separated into combustion exhaust gas and powder via the flue 12 and the cyclone device 90.
[0102] A bag filter 92 is connected to the cyclone device 90 via a cooling device 91 for cooling the combustion exhaust gas. The cooling device 91 is used to cool the combustion exhaust gas to a temperature below a certain level when dust (powder) adheres to the surface of the filter cloth of the bag filter 92, because if the combustion exhaust gas is at a high temperature, it will damage the filter cloth and no adhesion effect can be obtained. According to this structure, the combustion exhaust gas discharged from the bag filter 92 can be exhausted in a state where the solid components are substantially removed.
[0103] In the case of using a multi-tubular once-through boiler with the above structure, as Figure 11 shown, a structure can be adopted in which the cyclone device 90 and the cooling device 91 are respectively connected to each multi-tubular once-through boiler 100, and the discharge paths from each cooling device 91 are aggregated into one and guided to the bag filter 92.
[0104] The multi-tubular once-through boiler 100 constructed as described above, when using recycled oil (waste oil) as the combustion fuel of the burner 10, during the operation of the multi-tubular once-through boiler 100, by intermittently injecting steam from the multiple nozzles 50, 60, 70 arranged in the first nozzle row, the second nozzle row, and the third nozzle row, an air flow is generated around the water tube row, and the occurrence of residual ash adhering to the inner water tube row 3 and the outer water tube row 4 in the combustion chamber 9 can be suppressed.
[0105] In particular, since steam is injected around the water tube row during the operation of the multi-tubular once-through boiler 100, the adhesion of residual ash can be suppressed, and the situation where the attached residual ash firmly adheres after the multi-tubular once-through boiler stops can be prevented.
[0106] Moreover, by intermittently injecting steam, the temperature drop on the surface of the water tube rows (3, 4) caused by the collision of steam at a temperature (about 150°C to 175°C) lower than the temperature in the combustion chamber (about 900°C to 1000°C) can be suppressed, without hindering the heating of the water tube rows.
[0107] Reference Numeral Explanation
[0108] 1: Upper header; 2: Lower header; 3, 3L, 3R: Inner water tube row; 4, 4L, 4R: Outer water tube row; 5: Inner flue gas port; 5A: Cutout portion; 6: Outer flue gas port; 7: Combustion gas passage; 8: Fins for closing; 9: Combustion chamber; 10: Burner; 12: Flue; 13: Refractory; 14: Insulating material; 20: Main body; 21: Hinge portion; 22: Cover (door); 23: Water supply port; 24: Steam discharge port; 30: Partition wall; 40a, 40b: Closing plate; 41: Upper cutout portion; 50: Nozzle (first nozzle group); 51: Circular pipe; 60: Nozzle (second nozzle group); 61: Semi-circular pipe; 70: Nozzle (third nozzle group); 71: Circular pipe; 80: Steam separator; 82: Pressure gauge; 83: Safety valve; 84: Branch; 85: Injection control device; 90: Cyclone device; 91: Cooling device; 92: Bag filter; 100: Multi-tubular once-through boiler.
Claims
1. A multi-tubular once-through boiler having a combustion chamber supplied with combustion gas from a burner provided at one end side, in which a tube bank composed of a plurality of water tubes is provided, and the boiler water supplied into the water tubes is heated and evaporated by the combustion gas to take out the consumed steam, characterized in that, This multi-tubular once-through boiler uses recycled oil as fuel and is provided with a plurality of nozzles for injecting steam onto the surface of the water tube bank. Thus, during the operation of the multi-tubular once-through boiler, steam is injected to inhibit the adhesion of ash residues generated by the combustion of recycled oil to the surface side of the water tube bank due to the use of recycled oil.
2. The multi-tubular once-through boiler according to claim 1, wherein, This multi-tubular once-through boiler is provided with an injection control device for controlling the injection time of the steam injected from the nozzles, and steam is intermittently injected during the operation of the multi-tubular once-through boiler.
3. The multi-tubular once-through boiler according to claim 1, wherein, The steam injected from the nozzles is used by feedback of the consumed steam obtained from the multi-tubular once-through boiler.
4. The multi-tubular once-through boiler according to claim 3, wherein, The steam is supplied by branching the consumed steam taken out from the multi-tubular once-through boiler.
5. The multi-tubular once-through boiler according to claim 1, wherein, The first nozzle row composed of the plurality of nozzles is arranged at a position from the partition wall surface to the water tube bank. The partition wall is provided in the combustion chamber to cause the combustion gas from the burner to collide and flow backward.
6. The multi-tubular once-through boiler according to claim 1, wherein, The water tube bank is composed of an inner water tube bank and an outer water tube bank. At a position facing the gap between the inner water tube bank and the outer water tube bank from the inner surface side of the closing plate provided on the combustion chamber side of the burner, a second nozzle row composed of a plurality of nozzles is arranged.
7. The multi-tubular once-through boiler according to claim 6, wherein, At a position facing the gap between the inner water tube bank and the outer water tube bank from the inner surface side of the closing plate behind the partition wall provided on the side opposite to the burner, a third nozzle row composed of a plurality of nozzles is arranged.
8. The multi-tubular once-through boiler according to claim 5, wherein, The injection angle of the steam in each nozzle of the first nozzle row is 100 degrees to 115 degrees.
9. The multi-tubular once-through boiler according to claim 7, wherein, The injection angle of the steam in each nozzle of the second nozzle row and the third nozzle is 10 degrees to 20 degrees.
10. The multi-tubular once-through boiler according to claim 1, wherein, This multi-tubular once-through boiler is provided with a flue communicating with the combustion chamber, and a cyclone device is connected to the flue.
11. The multi-tubular once-through boiler according to claim 10, wherein, On the flue, a bag filter is connected to the gas outlet of the combustion gas in the cyclone device via a cooling device.
12. The multi-tubular once-through boiler according to claim 11, wherein, One bag filter is connected to a plurality of cyclone devices and cooling devices.
13. A multi-tubular once-through boiler that connects both end sides of each of a plurality of water tubes and supplies boiler water to each water tube. On the other hand, a combustion chamber is formed inside each water tube, and the combustion gas from the combustion chamber is supplied to the surface side of the plurality of water tubes to heat and evaporate the boiler water in the water tubes, and the consumed steam is taken out, characterized in that, This multi-tubular once-through boiler uses recycled oil as fuel. This multi-tubular once-through boiler is formed with a door on one end side facing the combustion chamber, and a burner for supplying combustion gas to the combustion chamber is provided on the outer side surface of the door. The combustion chamber is in a cylindrical shape extending in the horizontal direction. Each of the water tubes is in an arc shape respectively arranged on the left and right sides of the combustion chamber. For the water tube bank arranged on the left side of the combustion chamber, it is respectively connected by a linear left upper header provided at the upper end and a linear left lower header provided at the lower end. For the water tube bank arranged on the right side of the combustion chamber, it is respectively connected by a linear right upper header provided at the upper end and a linear right lower header provided at the lower end. The water tube bank is composed of an inner water tube bank and an outer water tube bank. Each water tube of the outer water tube bank is arranged between each water tube of the inner water tube bank. The water tubes constituting the left and right inner water tube banks are connected by sealing fins, and the water tubes constituting the left and right outer water tube banks are connected by sealing fins. A partition wall is provided near the end of the inner water tube row at the injection destination of the combustion gas to partition the combustion chamber, so that after the supplied combustion gas collides with the partition wall, it flows backward and returns to the door side. And, An inner smoke passage opening is formed between the end water tube of the inner water tube row on the door side of the combustion chamber and the combustion chamber wall on the door side. Cutouts are formed only on the closing fins that connect the water tubes of the inner water tube row and whose number starting from the door side is 10% to 20% of the total number of water tubes. On the other hand, A plurality of nozzles for injecting steam are arranged on the combustion chamber side of the partition wall in a manner along the vicinity of the inner water tube row.
14. The multi-tubular once-through boiler according to claim 13, wherein, A flue communicating with the combustion chamber is arranged on the upper surface of the combustion chamber on the side opposite to the door side. Upper cutouts are formed on a plurality of closing fins of the outer water tube row at the position facing the opening of the flue.
15. The multi-tubular once-through boiler according to claim 13 or 14, wherein, A plurality of nozzles for injecting steam into the gap between the inner water tube row and the outer water tube row are arranged at the position on the door side of the combustion chamber facing the gap.
16. The multi-tubular once-through boiler according to claim 13 or 14, wherein, A plurality of nozzles for injecting steam into the gap between the inner water tube row and the outer water tube row are arranged at the position on the inner surface side of the closing plate provided on the side opposite to the door side of the combustion chamber facing the gap.
17. The multi-tubular once-through boiler according to claim 13, wherein, This multi-tubular once-through boiler is provided with an injection control device that intermittently controls the steam injected from the nozzles during the operation of the multi-tubular once-through boiler.
18. A method for operating a multi-tubular once-through boiler, the multi-tubular once-through boiler connecting both ends of each of a plurality of water pipes respectively and supplying boiler water to each water pipe, on the other hand, forming a combustion chamber inside each water pipe, supplying combustion gas from a burner provided at one end side of the combustion chamber to the surface side of a water pipe row composed of a plurality of water pipes to heat and evaporate the boiler water in the water pipe, and taking out the consumed steam, characterized in that, Using recycled oil as fuel, steam is intermittently injected from the plurality of arranged nozzles to the surface side of the water tube row during the operation of the multi-tubular once-through boiler, thereby suppressing the adhesion of residual ash generated by the combustion of recycled oil to the surface side of the water tube row caused by using recycled oil.
19. The method for operating a multi-tubular once-through boiler according to claim 18, wherein, The intermittent injection of the steam is 5 seconds to 15 seconds per 1 hour to 2 hours.