Arrangement type of steam-water system of oil burning boiler

Abstract

The invention discloses an oil burning boiler steam-water system arrangement type, and relates to the technical field of oil burning boilers. The problem that the corrosion rate of vanadate with the melting point lower than the temperature is greatly increased due to the fact that the pipe wall temperature of part of high-temperature heating surfaces exceeds the temperature due to the fact that the first heating surface, making contact with smoke, of an existing oil burning boiler is a second-stage superheater is solved. The system comprises a flue gas channel, a hanging pipe in which a working medium can flow is arranged in the flue gas channel, a first-stage superheater, a second-stage superheater, a third-stage superheater, a second-stage reheater, a first-stage reheater and a coal economizer are sequentially arranged in the flue gas channel in the flue gas flowing direction, and the first-stage superheater with good cooling serves as a platen superheater and is arranged at an outlet of a hearth; compared with the third-stage superheater, the steam temperature of the second-stage superheater is lower, the second-stage superheater is arranged on the upper portion of the first-stage superheater with the high smoke temperature, the superheaters and the reheaters can effectively reduce the pipe wall temperature of the heating surface, stainless steel materials are prevented from being adopted for the pipes of the superheaters, and the high-temperature corrosion resistance of the heating surface of the oil burning boiler is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil-fired boilers, and in particular to an arrangement type of a steam-water system of an oil-fired boiler. Background Art

[0002] Oil-fired boilers refer to boilers that use oil as fuel, including diesel, waste oil and other oil-fired boilers. Due to the presence of vanadium in oil, the steam temperature at the outlet of the superheater and reheater of most oil-fired boilers is set at 540°C to prevent the temperature of the heating surface tube wall from being too high and causing high-temperature corrosion problems in the corrosion temperature range of vanadates.

[0003] However, the first heating surface of a conventional oil-fired boiler that contacts the flue gas is the secondary superheater, which can easily cause the wall temperature of some high-temperature heating surfaces to exceed 600°C, greatly increasing the corrosion rate of vanadates whose melting point is lower than this temperature. In addition, pipes with wall temperatures exceeding 600°C inevitably use stainless steel materials, which have worse resistance to high-temperature corrosion than conventional alloy steels, further exacerbating the corrosion problem.

[0004] In summary, the first heating surface of the existing oil-fired boiler that contacts the flue gas is the secondary superheater, and there is a problem that the temperature of some high-temperature heating surface tube walls exceeds 600°C, which greatly increases the corrosion rate of vanadates with a melting point below this temperature. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the first heating surface of the oil-fired boiler in contact with the flue gas is a secondary superheater, and the temperature of the tube wall of some high-temperature heating surfaces exceeds 600°C, which greatly increases the corrosion rate of vanadates with a melting point lower than this temperature. Further, a layout type of the steam-water system of an oil-fired boiler is provided.

[0006] The technical solution of the present invention is: a layout type of steam-water system of an oil-fired boiler, including: a flue gas channel connected to a furnace, a hanging pipe with a flowing working medium in the flue gas channel, and a primary superheater, a secondary superheater, a tertiary superheater, a secondary reheater, a primary reheater and an economizer arranged in sequence in the flue gas flow direction in the flue gas channel.

[0007] Further, the smoke passage includes a front smoke passage and a rear smoke passage formed by a middle partition wall, the smoke flows in from the front smoke passage, and the smoke flows out from the rear smoke passage;

[0008] The primary superheater, the secondary superheater, the tertiary superheater and the secondary reheater are located in the front flue, and the primary reheater and the economizer are located in the rear flue.

[0009] Furthermore, the middle partition wall is a water-cooled wall structure.

[0010] Furthermore, the front flue and the rear flue are both arranged vertically.

[0011] Furthermore, a front row of hanging pipes and a rear row of hanging pipes are arranged in the front flue, and a rear hanging pipe is arranged in the rear flue.

[0012] Furthermore, the front row of hanging pipes is formed by a portion of the front water-cooled wall, and the rear row of hanging pipes and the middle partition wall are formed by the water-cooled connecting pipes at the bottom of the steam drum.

[0013] Furthermore, the rear hanging pipe is formed by the economizer outlet header.

[0014] Furthermore, the hanging pipes and the ceiling are both water-cooled wall structures.

[0015] Compared with the prior art, the present invention has the following effects:

[0016] 1. The layout type of the steam-water system of the oil-fired boiler provided by the present invention is that the first-stage superheater with better cooling is arranged at the furnace outlet as a screen superheater. The second-stage superheater has a lower steam temperature than the third-stage superheater and is arranged on the upper part of the first-stage superheater with higher smoke temperature. The third-stage superheater is arranged on the upper part of the second-stage superheater with relatively lower smoke temperature. The smoke temperature here is relatively low and the heating surfaces of the superheaters are all arranged downstream. The reheater adopts a second-stage arrangement, and the second-stage reheater is arranged above the third-stage superheater. The arrangement of the superheater and the reheater can effectively reduce the wall temperature of the heating surface pipe, avoid the use of stainless steel materials for the superheater pipes, and improve the high-temperature corrosion resistance of the heating surface of the oil-fired boiler.

[0017] 2. In the layout of the steam-water system of the oil-fired boiler provided by the present invention, the working fluid in the hanging pipe flows upward, which is beneficial to the safety of water circulation by virtue of the natural rise of high-temperature steam and water.

[0018] 3. The layout of the steam-water system of the fuel oil boiler provided by the present invention completely eliminates the more complicated ceiling-wall superheater structure of conventional tower-type, box-type, and Π-type fuel oil boilers, which is beneficial to reducing steam-water resistance and reducing boiler costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the layout of the steam-water system of the oil-fired boiler of the present invention.

[0020] In the figure: 1. Flue gas duct; 2. First-stage superheater; 3. Second-stage superheater; 4. Third-stage superheater; 5. Second-stage reheater; 6. First-stage reheater; 7. Economizer; 8. Middle partition wall; 9. Front flue; 10. Rear flue; 11. Front row of hanging pipes; 12. Rear row of hanging pipes; 13. Rear hanging pipes; 14. Steam drum; 15. Water-cooled connecting pipe. DETAILED DESCRIPTION

[0021] Specific implementation method 1: Combination Figure 1 To illustrate this embodiment, this embodiment includes a flue gas channel 1, in which there is a hanging pipe for a flowing working medium, the working medium can be high-temperature steam, and in the flue gas channel 1, a primary superheater 2, a secondary superheater 3, a tertiary superheater 4, a secondary reheater 5, a primary reheater 6 and an economizer 7 are sequentially arranged along the flue gas flow direction. To ensure that the reheated steam temperature meets the standard, the secondary reheater 5 adopts a countercurrent arrangement, and the primary superheater 2 is a screen type superheater.

[0022] In the layout type of the steam-water system of the oil-fired boiler of this embodiment, the first-stage superheater 2 with better cooling is arranged at the furnace outlet as a screen superheater. The second-stage superheater 3 has a lower steam temperature than the third-stage superheater 4 and is arranged on the upper part of the first-stage superheater 2 with higher smoke temperature. The third-stage superheater 4 is arranged on the upper part of the second-stage superheater 3 with relatively lower smoke temperature, where the smoke temperature is lower and the superheater heating surfaces are all arranged downstream. The reheater adopts a second-stage arrangement, and the second-stage reheater 5 is arranged above the third-stage superheater 4. The arrangement of the superheater and the reheater can effectively reduce the wall temperature of the heating surface pipes, avoid the use of stainless steel materials for the superheater pipes, and improve the high-temperature corrosion resistance of the heating surface of the oil-fired boiler.

[0023] Specific implementation method 2: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the flue gas passage 1 includes a front flue 9 and a rear flue 10 formed by a middle partition wall 8. The flue gas flows in from the front flue 9. The middle partition wall 8 is formed with a loosening pipe. The flue gas passes through the loosening pipe and enters the rear flue 10, and then flows out from the rear flue 10. The first-stage superheater 2, the second-stage superheater 3, the third-stage superheater 4 and the second-stage reheater 5 are located in the front flue 9, and the first-stage reheater 6 and the economizer 7 are located in the rear flue 10. The formation of the two flues is longer, which has a better effect on absorbing heat in the flue gas and reduces energy waste. Other components and connection relationships are the same as those of the first embodiment.

[0024] Specific implementation method three: Combination Figure 1 This embodiment is described. The difference between this embodiment and the second embodiment is that the middle partition wall 8 is a water-cooled wall structure, and the middle partition wall 8 can also absorb the heat in the flue gas, and the heat absorption effect is better. The other components and connection relationships are the same as those of the second embodiment.

[0025] Specific implementation method four: Combination Figure 1 This embodiment is described. The difference between this embodiment and the second embodiment is that the front flue 9 and the rear flue 10 are both arranged vertically, and the working fluid in the hanging pipe flows upward, which is beneficial to the safety of water circulation by virtue of the natural rise of high-temperature steam and water. The other components and connection relationships are the same as those of the second embodiment.

[0026] Specific implementation method five: Combination Figure 1This embodiment is described. The difference between this embodiment and the fourth embodiment is that the front flue 9 is provided with a front hanging pipe 11 and a rear hanging pipe 12, and the rear flue 10 is provided with a rear hanging pipe 13. The number of hanging pipes is large, and the heat in the flue gas is absorbed at the same time, and the absorption area is larger, thereby improving the absorption efficiency. The other components and connection relationships are the same as those of the fourth embodiment.

[0027] Specific implementation method six: Combination Figure 1 This embodiment is described. The difference between this embodiment and the fifth embodiment is that the front hanging pipe 11 is formed by part of the front water-cooled wall, and the rear hanging pipe 12 and the middle partition wall 8 are formed by the water-cooled connecting pipe 15 at the bottom of the steam drum 14, and the overall structure is simpler. The other components and connection relationships are the same as those of the fifth embodiment.

[0028] Specific implementation method seven: Combination Figure 1 This embodiment is described. The difference between this embodiment and the fifth embodiment is that the rear hanging pipe 13 is formed by the outlet header of the economizer 7, and no additional structure is required. The arrangement of the rear hanging pipe 13 can be realized by only using the economizer 7, which is more convenient to use. The other components and connection relationships are the same as those of the fifth embodiment.

[0029] Specific implementation method eight: Combination Figure 1 This embodiment is described. The difference between this embodiment and the specific embodiment 1 is that the hanging pipe and the ceiling are both water-cooled wall structures, and the upper part of the rear water-cooled wall serves as the rear wall and ceiling pipe. The structure is simpler and the relatively complex ceiling wall superheater structure of conventional tower, box, and Π-type oil-fired boilers is completely eliminated. The other components and connection relationships are the same as any one of the specific embodiments 1 to 7.

[0030] Working principle of this implementation:

[0031] The flue gas first enters the front flue 9 from the furnace, heats the primary superheater, the secondary superheater 3, the tertiary superheater 4, the secondary reheater 5, the front hanging pipes 11 and the rear hanging pipes 12 in the front flue 9, and then passes through the exhaust pipe of the middle partition wall 8 to enter the rear flue 10, heats the primary reheater 6, the economizer 7 and the rear hanging pipe 13, and then is discharged.

[0032] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or several specific embodiments can also achieve the purpose of the invention.

Claims

1. A layout of a steam-water system for an oil-fired boiler, comprising: A flue gas channel (1) connected to a furnace, wherein the flue gas channel (1) has a hanging pipe for a flowing working medium, and is characterized in that a primary superheater (2), a secondary superheater (3), a tertiary superheater (4), a secondary reheater (5), a primary reheater (6) and an economizer (7) are sequentially arranged in the flue gas channel (1) along the flue gas flow direction.

2. The arrangement of the steam-water system of an oil-fired boiler according to claim 1 is characterized in that: The smoke passage (1) comprises a front smoke passage (9) and a rear smoke passage (10) formed by a middle partition wall (8), the smoke flows in from the front smoke passage (9) and the smoke flows out from the rear smoke passage (10); The primary superheater (2), the secondary superheater (3), the tertiary superheater (4) and the secondary reheater (5) are located in the front flue (9), and the primary reheater (6) and the economizer (7) are located in the rear flue (10).

3. The arrangement of the steam-water system of an oil-fired boiler according to claim 2 is characterized in that: The middle partition wall (8) is a water-cooled wall structure.

4. The arrangement of the steam-water system of an oil-fired boiler according to claim 2 is characterized in that: The front flue (9) and the rear flue (10) are both arranged vertically.

5. The arrangement of the steam-water system of an oil-fired boiler according to claim 4 is characterized in that: A front row of hanging pipes (11) and a rear row of hanging pipes (12) are arranged in the front flue (9), and a rear hanging pipe (13) is arranged in the rear flue (10).

6. The arrangement of the steam-water system of an oil-fired boiler according to claim 5 is characterized in that: The front row of hanging pipes (11) are formed by part of the front water-cooled wall, and the rear row of hanging pipes (12) and the middle partition wall (8) are formed by the water-cooled connecting pipes (15) at the bottom of the steam drum (14).

7. The arrangement of the steam-water system of an oil-fired boiler according to claim 5 is characterized in that: The rear hanging pipe (13) is formed by the economizer (7) outlet header.

8. A layout of a steam-water system for a fuel oil boiler according to any one of claims 1 to 7, characterized in that: The hanging pipes and the ceiling are both water-cooled wall structures.

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