Arrangement of a fuel oil boiler steam-water system

Abstract

The application relates to a fuel oil boiler steam-water system arrangement type, and relates to the technical field of fuel oil boilers. In order to solve the problem that the first heating surface of the existing fuel oil boiler in contact with flue gas is a secondary superheater, and that the tube wall temperature of part of the high-temperature heating surface exceeds a certain temperature, so that the corrosion rate of vanadate with a melting point lower than the temperature is greatly increased, the application comprises a flue gas channel, a hanging pipe with flowable working medium in the flue gas channel, a primary superheater, a secondary superheater, a tertiary superheater, a secondary reheater, a primary reheater and a coal economizer arranged in the flue gas channel in sequence along the flue gas flow direction, the primary superheater with good cooling is arranged at the furnace outlet as a screen-type superheater, the steam temperature of the secondary superheater is lower than that of the tertiary superheater, and the secondary superheater is arranged at the upper portion of the primary superheater with higher smoke temperature, the arrangement of the superheater and the reheater can effectively reduce the wall temperature of the heating surface tube, the superheater tube is not made of stainless steel, and the high-temperature corrosion resistance of the heating surface of the fuel oil boiler is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel oil boiler, in particular to a fuel oil boiler steam-water system arrangement type. BACKGROUND

[0002] Fuel oil boiler refers to the boiler using fuel oil as fuel, including diesel, waste oil and other oil boilers. Since vanadium exists in fuel oil, the steam temperature at the outlet of the superheater and reheater of most fuel oil boilers is set at 540 DEG C to prevent high-temperature corrosion problems caused by the temperature of the tube wall of the heating surface in the vanadate corrosion temperature range.

[0003] However, the first heating surface of the conventional fuel oil boiler in contact with flue gas is the secondary superheater, which is prone to cause the tube wall temperature of part of the high-temperature heating surface to exceed 600 DEG C, so that the corrosion rate of vanadate with a melting point lower than this temperature increases significantly, and the tubes with a wall temperature exceeding 600 DEG C inevitably use stainless steel material, which has poorer high-temperature corrosion resistance than conventional alloy steel, further enhancing the corrosion problem.

[0004] In summary, the first heating surface of the existing fuel oil boiler in contact with flue gas is the secondary superheater, which has the problem of part of the high-temperature heating surface tube wall temperature exceeding 600 DEG C, which significantly increases the corrosion rate of vanadate with a melting point lower than this temperature. SUMMARY

[0005] The present application aims to solve the problem that the first heating surface of the fuel oil boiler in contact with flue gas is the secondary superheater, which has part of the high-temperature heating surface tube wall temperature exceeding 600 DEG C, which significantly increases the corrosion rate of vanadate with a melting point lower than this temperature. Further, a fuel oil boiler steam-water system arrangement type is provided.

[0006] The technical solution of the present application is: a fuel oil boiler steam-water system arrangement type, comprising: a flue gas passage in communication with a furnace, the flue gas passage having a hanging pipe with flowable working medium therein, the flue gas passage having a first superheater, a second superheater, a third superheater, a second reheater, a first reheater and an economizer arranged in sequence along the flue gas flow direction.

[0007] Further, the flue gas passage includes a front flue and a rear flue formed by an intermediate partition wall, the flue gas flows into the front flue, and the flue gas flows out of the rear flue;

[0008] The first superheater, the second superheater, the third superheater and the second reheater are located in the front flue, and the first reheater and the economizer are located in the rear flue.

[0009] Further, the intermediate partition wall is a water-cooled wall structure.

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

[0011] Further, the front flue and the rear flue are vertically arranged.

[0012] Further, the front flue and the rear flue are vertically arranged.

[0013] Further, the front flue and the rear flue are vertically arranged.

[0014] Further, the front flue and the rear flue are vertically arranged.

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

[0016] 1. The fuel oil boiler steam-water system arrangement type provided by the present application has the following advantages: the good first-stage superheater is arranged as a screen-type superheater at the outlet of the furnace, the second-stage superheater has a lower steam temperature than the third-stage superheater, is arranged at the upper portion of the first-stage superheater which has a higher flue gas temperature, and the third-stage superheater is arranged at the upper portion of the second-stage superheater which has a relatively lower flue gas temperature; the flue gas temperature is low at this position, and the heating surfaces of the superheaters are arranged in a parallel flow manner; the reheater is arranged in two stages, and the second-stage reheater is arranged above the third-stage superheater; the arrangement of the superheaters and the reheater can effectively reduce the wall temperature of the heating surface tubes, avoid the use of stainless steel for the superheater tubes, and improve the high-temperature corrosion resistance of the heating surface of the fuel oil boiler.

[0017] 2. The fuel oil boiler steam-water system arrangement type provided by the present application has the following advantages: the working medium in the hanger tubes flows upward, and the natural upward flow of the high-temperature steam-water is beneficial to the safety of the water circulation.

[0018] 3. The fuel oil boiler steam-water system arrangement type provided by the present application has the following advantages: the arrangement completely removes the complex ceiling and wall-enclosed superheater structure of the conventional tower-type, box-type and Π-type fuel oil boilers, and is beneficial to reducing the steam-water resistance and the cost of the boiler. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the fuel oil boiler steam-water system arrangement type of the present application.

[0020] In the figure: 1, flue gas passage; 2, first-stage superheater; 3, second-stage superheater; 4, third-stage superheater; 5, second-stage reheater; 6, first-stage reheater; 7, coal economizer; 8, intermediate partition wall; 9, front flue; 10, rear flue; 11, front row of hanger tubes; 12, rear row of hanger tubes; 13, rear hanger tube; 14, steam drum; 15, water-cooled connecting pipe. DETAILED DESCRIPTION

[0021] Specific implementation one: combine Figure 1 The embodiment is described, the embodiment includes flue gas passage 1, the hanging pipe with flowable working medium in flue gas passage 1, the working medium can be high-temperature steam, flue gas passage 1 is sequentially provided with primary superheater 2, secondary superheater 3, tertiary superheater 4, secondary reheater 5, primary reheater 6 and coal economizer 7 in the direction of flue gas flow, to ensure that the temperature of reheated steam meets the standard, the secondary reheater 5 is arranged in counterflow, and the primary superheater 2 is arranged as a screen-type superheater at the outlet of the furnace.

[0022] The fuel oil boiler steam-water system arrangement type of the embodiment is arranged as a screen-type superheater, the primary superheater 2 is arranged at the outlet of the furnace, the steam temperature of the secondary superheater 3 is lower than that of the tertiary superheater 4, and the secondary superheater 3 is arranged at the upper portion of the primary superheater 2 with higher flue gas temperature, the tertiary superheater 4 is arranged at the upper portion of the secondary superheater 3 with relatively lower flue gas temperature, the flue gas temperature is lower at this position, and the heating surfaces of the superheaters are arranged in parallel flow, and the reheaters are arranged in two stages, the secondary reheater 5 is arranged above the tertiary superheater 4, and the arrangement of the superheaters and the reheaters can effectively reduce the wall temperature of the heating surface tubes, avoid the use of stainless steel for the superheater tubes, and improve the high-temperature corrosion resistance of the heating surface of the fuel oil boiler.

[0023] Specific implementation two: combine Figure 1 The embodiment is described, and the difference between the embodiment and specific implementation one is that the flue gas passage 1 includes front flue 9 and rear flue 10 formed by intermediate partition wall 8, flue gas flows from the front flue 9, the intermediate partition wall 8 is formed with a draw-off pipe, flue gas passes through the draw-off pipe to enter the rear flue 10, and then flows out from the rear flue 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, the primary reheater 6 and the coal economizer 7 are located in the rear flue 10, the two flues are longer, the heat absorption effect of flue gas is better, and energy waste is reduced. The other components and connection relationships are the same as those of specific implementation one.

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

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

[0026] Specific implementation five: combine Figure 1The difference between the embodiment and the fourth embodiment is that the front row of hanging pipes 11 and the rear row of hanging pipes 12 are arranged in the front flue 9, and the rear hanging pipe 13 is arranged in the rear flue 10. The number of hanging pipes is large, and the heat in the flue gas is absorbed, the absorption area is larger, and the absorption efficiency is improved. The other components and connection relationships are the same as those in the fourth embodiment.

[0027] The sixth embodiment is combined with the fifth embodiment. Figure 1 The difference between the embodiment and the fifth embodiment is that the front row of hanging pipes 11 is formed by part of the front water-cooled wall, the rear row of hanging pipes 12 and the intermediate partition wall 8 are formed by the water-cooled connecting pipe 15 at the lower part of the steam drum 14, and the overall structure is simpler. The other components and connection relationships are the same as those in the fifth embodiment.

[0028] The seventh embodiment is combined with the fifth embodiment. Figure 1 The difference between the 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 needed. The arrangement of the rear hanging pipe 13 can be realized by using the economizer 7, and the use is more convenient. The other components and connection relationships are the same as those in the fifth embodiment.

[0029] The eighth embodiment is combined with the first embodiment. Figure 1 The difference between the embodiment and the first embodiment is that the hanging pipes and the ceiling are both water-cooled wall structures, the upper part of the rear water-cooled wall is used as the rear wall and the ceiling pipe, the structure is simpler, and the complex ceiling wall superheater structure of the conventional tower type, box type and Π type oil-fired boiler is completely removed. The other components and connection relationships are the same as those in any one of the first to seventh embodiments.

[0030] Working principle of the embodiment:

[0031] The flue gas first enters the front flue 9 from the furnace, heats the first-stage superheater, the second-stage superheater 3, the third-stage superheater 4, the second-stage reheater 5, the front row of hanging pipes 11 and the rear row of hanging pipes 12 in the front flue 9, then passes through the draw-off pipe of the intermediate partition wall 8 into the rear flue 10, heats the first-stage reheater 6, the economizer 7 and the rear hanging pipe 13, and then is discharged.

[0032] The content of the application is not limited to the above-mentioned embodiments, and the combination of one or more embodiments can also achieve the purpose of the application.

Claims

1. A steam-water system layout for an oil-fired boiler, comprising: A flue gas passage (1) connected to the furnace, wherein the flue gas passage (1) has a hanging pipe for a flowable working fluid, 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 arranged sequentially along the flue gas flow direction in the flue gas passage (1). 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) and the flue gas flows out from the rear flue (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).

2. The steam-water system layout of an oil-fired boiler according to claim 1, characterized in that, The intermediate partition wall (8) is a water-cooled wall structure.

3. The steam-water system layout of an oil-fired boiler according to claim 1, characterized in that, Both the front flue (9) and the rear flue (10) are vertically arranged.

4. The steam-water system layout of an oil-fired boiler according to claim 3, characterized in that, The front flue (9) is provided with a front row of hanging pipes (11) and a rear row of hanging pipes (12), and the rear flue (10) is provided with a rear hanging pipe (13).

5. The steam-water system layout of an oil-fired boiler according to claim 4, characterized in that, The front row of hanging pipes (11) is formed by a portion 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).

6. The steam-water system layout of an oil-fired boiler according to claim 4, characterized in that, The rear hanging pipe (13) is formed by the outlet header of the economizer (7).

7. A steam-water system layout for an oil-fired boiler according to any one of claims 1-6, characterized in that, Both the hanging pipes and the ceiling are water-cooled wall structures.

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