CN110542076A - Steam extraction modification method, structure and control method of flue gas baffle-based temperature-regulating boiler - Google Patents
Steam extraction modification method, structure and control method of flue gas baffle-based temperature-regulating boiler Download PDFInfo
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- CN110542076A CN110542076A CN201910693522.7A CN201910693522A CN110542076A CN 110542076 A CN110542076 A CN 110542076A CN 201910693522 A CN201910693522 A CN 201910693522A CN 110542076 A CN110542076 A CN 110542076A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
- F22G5/00—Controlling superheat temperature
- F22G5/04—Controlling superheat temperature by regulating flue gas flow, e.g. by proportioning or diverting
Abstract
The invention discloses a steam extraction modification method, a steam extraction modification structure and a steam extraction modification control method for a flue gas baffle temperature-regulating boiler, wherein a low re-bypass pipeline and a low re-bypass control valve which are connected with part of horizontal pipe groups of a low-temperature reheater in parallel are arranged in an original low-temperature reheater horizontal pipe group, and/or a newly-added economizer pipe group which is connected with the original economizer pipe group in series or in parallel is added in the original economizer pipe group, an economizer bypass pipeline and an economizer bypass control valve are arranged, a water supply pipeline is connected with the newly-added economizer pipe group when the water supply pipeline is connected in series, and the newly-added economizer pipe group is connected with the original economizer pipe group when the water supply pipeline is connected in parallel and is arranged on the economizer bypass pipeline. According to the invention, by arranging the low-secondary bypass pipeline and the economizer bypass pipeline, part of the low-temperature reheater tube group and part of the economizer tube group are switched according to the requirement, so that the boiler can simultaneously meet the steam extraction working condition and the non-steam extraction working condition, and the adaptability of the boiler to industrial gas and urban heat supply is greatly improved.
Description
Technical Field
The invention relates to the technical field of boiler manufacturing and transformation, in particular to a steam extraction transformation method, a steam extraction transformation structure and a steam extraction control method of a temperature-regulating boiler based on a smoke baffle.
Background
The high-temperature level heating surface of the flue gas baffle temperature-regulating boiler is generally arranged at a hearth outlet and a horizontal flue, the low-temperature level heating surface is generally arranged at a rear vertical shaft double-flue, and a low-temperature reheater is independently arranged at one flue. The flue gas portion flowing through the flue where the low-temperature reheater is located is adjusted by adjusting the opening degree of the baffle below each flue of the rear vertical shaft, so that the temperature of the reheated steam can be adjusted.
In the in-service flue gas baffle temperature-regulating power station boiler, a newly-increased steam extraction point (a common steam extraction point is arranged at a main steam outlet and a reheat steam inlet) is used for industrial steam or urban heat supply, so that the thermodynamic balance of the operation of the boiler is broken, the flow of a working medium after the steam extraction point is relatively reduced, the temperature of the wall of a heating surface is increased, and the operation safety of the boiler is endangered.
in order to adapt to the steam extraction working condition, the boiler needs to be modified, and the traditional modification method is to reduce the area of a heating surface behind a steam extraction point. The traditional transformation method has the following defects:
1) The boiler is only suitable for steam extraction working conditions after being transformed. When the steam demand changes (the extraction steam is zero under extreme conditions), the conditions that the steam temperature does not reach the standard due to insufficient area of the heating surface can occur; it may also result in an excessive low-re-side flue gas fraction and tube wear.
2) The denitration inlet smoke temperature rises and deviates from the design working condition, so that the denitration operation cost rises; extreme conditions may result in the need to replace the high temperature catalyst to accommodate the higher denitration inlet flue gas temperatures.
3) Denitration entry cigarette temperature rises and will lead to boiler exhaust gas temperature to rise, and boiler efficiency descends, leads to the unit economic nature to descend.
Disclosure of Invention
aiming at the problems of the traditional steam extraction modification method, the invention provides a steam extraction modification method, a structure and a control method of a flue gas baffle plate temperature-regulating boiler.
The invention provides a steam extraction reconstruction method of a temperature-regulating boiler based on a smoke baffle plate, wherein a low re-bypass pipeline and a low re-bypass control valve which are connected with partial horizontal pipe groups of a low-temperature reheater in parallel are arranged in an original horizontal pipe group of the low-temperature reheater, and/or
The new economizer pipe set is added in the original economizer pipe set, the new economizer pipe set is connected with the original economizer pipe set in series or in parallel, an economizer bypass pipeline and an economizer bypass control valve are arranged, the water supply pipeline is connected with the new economizer pipe set when the new economizer pipe set is connected in series, and the water supply pipeline is connected with the original economizer pipe set when the new economizer pipe set is connected in parallel and the new economizer pipe set is arranged on the economizer bypass pipeline.
According to one embodiment of the steam extraction transformation method of the flue gas baffle temperature-regulating boiler, a low-temperature reheater intermediate header is added between any two levels of horizontal tube groups of the original low-temperature reheater, a cold re-pipeline connected with a low-temperature reheater inlet header is further connected with the low-temperature reheater intermediate header through a low re-bypass pipeline, a cold re-pipeline control valve is arranged on the cold re-pipeline, and/or a cold re-pipeline control valve is arranged on the cold re-pipeline
When the newly added economizer pipe group is connected with the original economizer pipe group in series, the newly added economizer pipe group is arranged in the combined flue, an economizer inlet header connected with the newly added economizer pipe group is added, the original economizer inlet header is replaced by an economizer middle header, a water supply pipeline is connected with the economizer inlet header, a water supply pipeline control valve is arranged on the water supply pipeline, and an economizer bypass pipeline is connected with the economizer middle header;
When the newly added economizer pipe group is connected with the original economizer pipe group in parallel, a water supply pipeline control valve is arranged on a water supply pipeline connected with an inlet header of the original economizer, the newly added economizer pipe group is arranged in a low-secondary side flue, an intermediate header of the economizer is added between any two stages of the pipe groups of the original economizer, and an economizer bypass pipeline is connected with the intermediate header of the economizer through the newly added economizer pipe group.
According to one embodiment of the steam extraction modification method of the flue gas baffle temperature-regulating boiler, under the steam extraction working condition, reheated steam flows through a low-temperature bypass pipeline and enters a low-temperature reheater horizontal tube group which is not bypassed and/or feed water flows through a newly-added economizer tube group; under the non-steam extraction working condition, the reheated steam flows through the original low-temperature reheater horizontal tube group and/or the feed water flows through the original economizer tube group.
The invention provides a steam extraction reconstruction structure based on a flue gas baffle temperature-adjusting boiler, wherein a low-temperature reheater arranged in a rear shaft flue of the flue gas baffle temperature-adjusting boiler comprises at least two levels of horizontal pipe groups, a newly-added low re-bypass pipeline, a low re-bypass control valve and a cold re-pipeline control valve, the low re-bypass pipeline is connected with a low-temperature reheater middle header arranged between any two levels of horizontal pipe groups and is arranged in parallel with partial horizontal pipe groups of the low-temperature reheater, and the cold re-pipeline is connected with a low-temperature reheater inlet header and/or
The economizer arranged in the rear shaft flue of the flue gas baffle temperature-regulating boiler comprises at least one-stage economizer pipe group, a newly-added economizer pipe group, an economizer bypass pipeline, an economizer bypass control valve and a water supply pipeline control valve, when the newly-added economizer pipe group is connected with the economizer pipe group in series, the water supply pipeline is connected with an inlet header of the newly-added economizer pipe group serving as an economizer inlet header, the economizer bypass pipeline is connected with the newly-added economizer pipe group in parallel and is connected with an economizer middle header or an economizer outlet header arranged between any two stages of economizer pipe groups;
When the newly added economizer pipe group and the economizer pipe group are arranged in parallel, the water supply pipeline is connected with the economizer inlet header, the economizer bypass pipeline is connected with the economizer middle header or the economizer outlet header arranged between any two stages of economizer pipe groups, and the newly added economizer pipe group is arranged on the economizer bypass pipeline and is arranged in parallel with part of the economizer pipe groups.
According to one embodiment of the steam extraction reforming structure based on the flue gas baffle temperature-adjusting boiler, the rear vertical shaft of the flue gas baffle temperature-adjusting boiler at least comprises two flues, a low-temperature reheater is arranged in the front flue, a low-temperature superheater and an economizer are arranged in the rear flue, and the reheated steam temperature is adjusted through the flue gas baffle below the flues.
According to one embodiment of the steam extraction reforming structure of the flue gas baffle temperature regulating boiler, each control valve is a butterfly valve or a gate valve, and the tube type of the economizer tube group is a plain tube type or a finned tube type.
According to one embodiment of the steam extraction modification structure of the flue gas baffle temperature-regulating boiler, when the additional economizer pipe group and the economizer pipe group are arranged in series, the additional economizer pipe group is arranged in the combined flue; when the additional economizer pipe group and the economizer pipe group are arranged in parallel, the additional economizer pipe group is arranged in the side flue of the low-temperature reheater.
The invention also provides a control method of the steam extraction reforming structure of the flue gas baffle temperature-regulating boiler, under the steam extraction working condition, opening a low re-bypass control valve, closing a cold re-pipeline control valve and controlling reheated steam to flow through a low re-bypass pipeline to enable a horizontal pipe group of at least one stage of low-temperature reheater to quit operation, and/or closing an economizer bypass control valve and opening a water supply pipeline control valve when a newly-added economizer pipe group and the economizer pipe group are arranged in series, and controlling water to flow through the newly-added economizer pipe group to enable the newly-added economizer pipe group to be put into operation;
And/or when the newly added economizer pipe group is connected with the economizer pipe group in series, the economizer bypass control valve is opened, the water supply pipe control valve is closed, and the water supply is controlled not to flow through the newly added economizer pipe group so that the newly added economizer pipe group is withdrawn from operation.
According to an embodiment of the control method of the steam extraction modification structure of the flue gas baffle thermoregulation boiler, when the added economizer pipe group and the economizer pipe group are arranged in parallel, under the steam extraction working condition, the economizer bypass control valve and the water supply pipeline control valve on the water supply pipeline are opened simultaneously, so that water supply flows through the added economizer pipe group and at least one stage of economizer pipe group simultaneously; and under the non-steam extraction working condition, closing the economizer bypass control valve, opening the water supply pipeline control valve and controlling the feed water not to flow through the newly added economizer pipe group so as to enable the newly added economizer pipe group to quit the operation.
The invention provides a steam extraction modification method, a steam extraction modification structure and a steam extraction control method of a flue gas baffle temperature-regulating boiler, wherein a low-temperature reheater pipe group and a coal economizer bypass pipe are partially switched according to requirements in a mode of arranging a low-temperature reheater pipe and a coal economizer bypass pipe, so that the boiler can simultaneously meet the steam extraction working condition and the non-steam extraction working condition, and the adaptability of the boiler to industrial gas and urban heat supply is greatly improved.
Drawings
Fig. 1 shows a schematic drawing of a steam extraction revamping structure of a flue gas baffle attemperation based boiler according to an exemplary embodiment of the present invention.
Fig. 2 shows a schematic drawing of a steam extraction retrofit structure of a flue gas baffle attemperation based boiler according to another exemplary embodiment of the present invention.
Description of reference numerals:
1. A low temperature reheater inlet header; 2. a low-temperature reheater horizontal primary tube group; 3. a low temperature reheater horizontal secondary tube bank; 4. a low-temperature reheater horizontal tertiary tube group; 5. a low temperature reheater vertical tube bank; 6. an economizer middle header; 7. a lower-level pipe group of the economizer; 8. an upper-level pipe group of the economizer; 9. a low-temperature superheater horizontal tube group; 10. a low-temperature superheater vertical tube group; 11. a low-temperature reheater side flue gas baffle; 12. a low-temperature superheater side flue gas baffle; 13. an economizer inlet header; 14. adding a coal economizer pipe group; 15. a water supply pipe control valve; 16. an economizer bypass control valve; 17. an economizer bypass conduit; 18. a cold recirculation line control valve; 19. a low re-bypass control valve; 20. a low-bypass line; 21. low temperature reheater intermediate header.
Detailed Description
all of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
Firstly, the steam extraction modification idea of the temperature-regulating boiler based on the smoke baffle is specifically explained.
Taking a certain 600MW in-service supercritical pulverized coal boiler as an example, the boiler is a rear shaft double-flue boiler, a low-temperature reheater is arranged in a front flue, a low-temperature superheater and an economizer are arranged in a rear flue, and the temperature of reheated steam is adjusted through a flue gas baffle positioned below the double flues. The superheaters are arranged in three stages and respectively comprise a low-temperature superheater positioned above a rear flue of the rear vertical shaft, a platen superheater positioned on the upper part of the hearth and a final superheater positioned at the outlet of the hearth; the reheaters are arranged in two stages, namely a high-temperature reheater located in the horizontal flue and a low-temperature reheater located in the front flue of the rear vertical shaft.
According to the boiler, steam needs to be extracted at a main steam outlet for 300t/h on the premise of ensuring the electric load due to the steam demand of peripheral chemical plants. For the boiler, the newly added steam extraction point increases the coal consumption, the furnace outlet smoke temperature and the furnace outlet smoke quantity are increased, and the reheat steam flow is basically maintained unchanged. In order to adapt to the steam extraction working condition, the traditional scheme needs to reduce the areas of part of high-temperature reheaters and low-temperature reheaters, reduce the heat absorption of the high-temperature reheaters, and simultaneously maintain the flue gas share at the side of the low-temperature reheater and the adjusting capacity of the flue gas adjusting baffle.
Table 1 below shows the comparison of the parameters with the previous conditions after the conventional retrofitting method. Through comparison, after steam extraction transformation, the temperature rise of the high-pressure side is equivalent to that of the original design, and although the smoke share of the low-pressure side is reduced to a certain degree, the smoke share is still in the adjustable range of the baffle plate of 30% -70%. According to the transformation scheme, the area of the reheater is reduced, and if the steam extraction requirement disappears, the requirement on the steam temperature cannot be met; simultaneously, the denitration inlet smoke temperature of the modification scheme has larger lifting amplitude, the high-load working condition exceeds 400 ℃, and the application temperature range of the conventional catalyst is exceeded, and if the high-temperature catalyst is replaced, the denitration operation cost is greatly increased. Simultaneously denitration entry cigarette temperature rises, also will lead to exhaust gas temperature to rise, and boiler efficiency descends.
TABLE 1 comparison of original design and conventional modified parameters of a 600MW supercritical pulverized coal fired boiler in service
Based on the technical scheme, the invention provides a steam extraction modification idea of the flue gas baffle plate temperature-regulating boiler. The bypass pipeline and the corresponding control valve are arranged on the low-level-to-level tube group, so that the reheated steam flows through the bypass pipeline under the steam extraction working condition and is dried and burned by the bypassed low-level-to-level tube group, and the purpose of reducing the area of a reheater is achieved; under the non-extraction working condition, the reheated steam flows through the original horizontal tube group, and the purpose of recovering the area of the reheater is achieved. A primary economizer pipe group is added and connected with the original economizer in series or in parallel, and a bypass pipeline is arranged, so that feed water flows through the newly added economizer pipe group under the steam extraction working condition, and the aim of reducing the smoke temperature at a denitration inlet is fulfilled; under the working condition of non-extraction, water is fed away from the bypass pipeline, and the economizer pipe group is added for dry combustion, so that the aim of recovering the running state of the original economizer is fulfilled.
The steam extraction modification method, the structure and the control method of the invention are further explained below with reference to the accompanying drawings.
According to an exemplary embodiment of the invention, the steam extraction modification method of the flue gas baffle thermoregulation boiler is to arrange a low re-bypass pipeline 20 and a low re-bypass control valve 19 which are connected with part of horizontal pipe groups of the low-temperature reheater in parallel in an original low-temperature reheater horizontal pipe group, and/or to add a new economizer pipe group 14 which is connected with the original economizer pipe group in series or in parallel in the original economizer pipe group and arrange an economizer bypass pipeline 17 and an economizer bypass control valve 16, wherein a water supply pipeline is connected with the new economizer pipe group 14 in series, and a water supply pipeline is connected with the original economizer pipe group in parallel and the new economizer pipe group 14 is arranged on the economizer bypass pipeline 17.
Thus, under steam extraction conditions, reheat steam is caused to flow through the low-temperature-bypass pipeline 20 into the low-temperature-reheater horizontal tube group that is not bypassed and/or feedwater is caused to flow through the newly added economizer tube group 14; under the non-steam extraction working condition, the reheated steam flows through the original low-temperature reheater horizontal tube group and/or the feed water flows through the original economizer tube group.
That is, the invention can be used for improving the bypass pipeline and the control assembly on the low-level-to-horizontal pipe group and adding the first-level economizer pipe group, the economizer bypass pipeline and the control assembly independently or simultaneously according to the working conditions.
During transformation, a low-temperature reheater intermediate header 21 can be added between any two levels of horizontal tube groups of the original low-temperature reheater, a cold re-pipeline connected with the low-temperature reheater inlet header 1 is connected with the low-temperature reheater intermediate header 21 through a low re-bypass pipeline 20, and a cold re-pipeline control valve 18 is arranged on the cold re-pipeline.
The low-temperature reheater bypass tube bank range can be set as required, only the low-temperature reheater primary tube bank can be bypassed, and the low-temperature reheater multi-stage tube bank can be bypassed, for example, a low-temperature reheater intermediate header 21 is added between the low-temperature reheater horizontal primary tube group 2 and the low-temperature reheater horizontal secondary tube group 3 so that the low-temperature reheater horizontal primary tube group 2 becomes a bypassed low-temperature reheater horizontal tube group, or the low-temperature reheater intermediate header 21 may be added between the low-temperature reheater horizontal secondary tube group 3 and the low-temperature reheater horizontal tertiary tube group 4, so that the low-temperature reheater horizontal primary tube group 2 and the low-temperature reheater horizontal secondary tube group 3 both become bypassed low-temperature reheater horizontal tube groups, and the original low-temperature reheater tube groups may be further partitioned again and a bypass range may be set, as long as adjustability of increasing or decreasing of the area of the low-temperature reheater is achieved.
When the newly added economizer pipe group 14 is connected in series with the original economizer pipe group, the newly added economizer pipe group 14 is arranged in the combined flue, an economizer inlet header 13 connected with the newly added economizer pipe group 14 is added, the original economizer inlet header is changed into an economizer middle header 6, a water supply pipeline is connected with the economizer inlet header 13, a water supply pipeline control valve 15 is arranged on the water supply pipeline, and an economizer bypass pipeline 17 is connected with the economizer middle header 6. When the newly added economizer pipe group 14 is connected with the original economizer pipe group in parallel, a water supply pipe control valve 15 is arranged on a water supply pipe connected with an inlet header of the original economizer, the newly added economizer pipe group 14 is arranged in a low-secondary side flue, an economizer middle header 6 can be added between any two stages of pipe groups of the original economizer, an economizer bypass pipe 17 is connected with the economizer middle header 6 through the newly added economizer pipe group 14, and when the original economizer is provided with only one stage pipe group, the economizer bypass pipe 17 can also be connected with an economizer outlet header through the newly added economizer pipe group 14.
Similarly, the range of the economizer bypass pipe group can be set as required, only the economizer pipe group can be newly added by bypassing, the original pipe group can be partitioned again, and the bypass range is set, so long as the aim of reducing the smoke temperature of the denitration inlet can be achieved.
Fig. 1 shows a schematic drawing of a steam extraction reforming structure of a flue gas baffle tempering boiler according to an exemplary embodiment of the present invention, and fig. 2 shows a schematic drawing of a steam extraction reforming structure of a flue gas baffle tempering boiler according to another exemplary embodiment of the present invention.
According to the reforming method, the invention also provides a steam extraction reforming structure of the flue gas baffle plate temperature-regulating boiler. Specifically, the rear vertical shaft of the flue gas baffle temperature-regulating boiler at least comprises two flues, a low-temperature reheater is arranged in the front flue, a low-temperature superheater and an economizer are arranged in the rear flue, and the temperature of reheated steam is regulated through a flue gas baffle positioned below the flues. According to one embodiment of the invention, the superheaters in the flue gas baffle temperature-regulating boiler are arranged in three stages and comprise a low-temperature superheater positioned above a rear flue of the rear vertical shaft, a platen superheater positioned at the upper part of a hearth and a final superheater positioned at the outlet of the hearth; the reheater in the flue gas baffle temperature regulating boiler is arranged in two stages, and comprises a high-temperature reheater positioned in a horizontal flue and a low-temperature reheater positioned in a front flue in a rear vertical shaft, but the invention is not limited to the arrangement.
As shown in fig. 1 and 2, according to an exemplary embodiment of the present invention, a low-temperature reheater disposed in a rear shaft flue of a flue gas damper attemperation boiler includes at least two stages of horizontal tube groups, and a low-re-bypass pipe 20, a low-re-bypass control valve 19, and a cold-re-pipe control valve 18 are newly added, the low-re-bypass pipe 20 being connected to a low-temperature reheater intermediate header 21 disposed between any two stages of the horizontal tube groups and being disposed in parallel with a part of the horizontal tube groups of the low-temperature reheater, and the cold-re-pipe being connected to a low-temperature reheater inlet header 1. Wherein the water supply pipe is also provided with a water supply pipe control valve 15.
Therefore, under the steam extraction working condition, the low-temperature reheater horizontal tube group which is bypassed is controlled to exit from the operation and be in a dry-burning state through the opening of the low-re-bypass control valve 19 and the closing of the cold re-pipeline control valve 18, and the area of the low-temperature reheater is reduced. Under the non-extraction working condition, the low-temperature reheater horizontal tube group which is bypassed is controlled to be put into operation through closing of the low-temperature-reheater bypass control valve 19 and opening of the cold-reheater pipeline control valve 18, and the area of the low-temperature reheater is restored to the original state.
For example, in the embodiment of fig. 1, the low-temperature reheater includes a low-temperature reheater horizontal primary tube group 2, a low-temperature reheater horizontal secondary tube group 3, a low-temperature reheater horizontal tertiary tube group 4, and a low-temperature reheater vertical tube group 5, a low-temperature reheater intermediate header 21 is disposed between the low-temperature reheater horizontal primary tube group 2 and the low-temperature reheater horizontal secondary tube group 3, and a low-temperature re-bypass pipe 20 is disposed between the cold re-pipe and the low-temperature reheater intermediate header 21. However, the present invention is not limited to this, and the range of the bypass tube group may be adjusted by adjusting the installation position of the low-temperature reheater intermediate header 21.
For the economizer, the economizer arranged in the flue of the rear shaft of the flue gas baffle temperature-adjusting boiler comprises at least one economizer pipe group, a newly-added economizer pipe group 14, an economizer bypass pipeline 17, an economizer bypass control valve 16 and a water supply pipeline control valve 15, when the newly-added economizer pipe group 14 is connected with the at least one economizer pipe group in series, the water supply pipeline is connected with a newly-added economizer pipeline inlet header serving as an economizer inlet header 13, and the economizer bypass pipeline 17 is connected with the newly-added economizer pipe group in parallel and is connected with an economizer middle header 6 or an economizer outlet header arranged between any two economizer pipe groups.
therefore, under the steam extraction working condition, the newly-added economizer pipe group is controlled to be put into operation by closing the economizer bypass control valve 16 and opening the water supply pipeline control valve 15, so that the area of the economizer is increased; under the non-steam extraction working condition, the newly-added economizer pipe group is controlled to exit the operation and be in a dry combustion state by opening the economizer bypass control valve 16 and closing the water supply pipeline control valve 15, and the area of the economizer is restored to the original state.
For example, the economizer in the embodiment of fig. 1 includes an economizer lower-stage tube group 7 and an economizer upper-stage tube group 8, a new economizer tube group 14 is arranged in series with the economizer lower-stage tube group 7 and the economizer upper-stage tube group 8, an inlet header of the new economizer tube group 14 is connected to the feed water pipe as an inlet header of the economizer, an original economizer inlet header is used as the economizer intermediate header 6, and an economizer bypass pipe 17 is arranged between the feed water pipe and the economizer intermediate header 6. However, the present invention is not limited to this, and the range of the bypass tube group may be adjusted by adjusting the installation position of the economizer intermediate header 6 or by directly using the economizer outlet header.
when the additional economizer pipe group 14 is arranged in parallel with the economizer pipe group, the water supply pipe is connected with the economizer inlet header 13, the economizer bypass pipe 17 is connected with the economizer middle header 6 or the economizer outlet header arranged between any two economizer pipe groups, and the additional economizer pipe group 14 is arranged on the economizer bypass pipe 17 and is arranged in parallel with part of or all the economizer pipe groups.
Therefore, under the steam extraction working condition, the newly-added economizer pipe group is controlled to be put into operation by opening the economizer bypass control valve 16 and opening the water supply pipeline control valve 15, the area of the economizer is increased, and the heat absorption of the front flue is increased; under the non-steam extraction working condition, the newly-added economizer pipe group is controlled to exit the operation and be in a dry combustion state by closing the economizer bypass control valve 16 and opening the water supply pipeline control valve 15, and the area of the economizer is restored to the original state.
For example, the economizer in the embodiment of fig. 2 includes an economizer lower-stage tube group 7 and an economizer upper-stage tube group 8, a new economizer tube group 14 is disposed in parallel with the economizer lower-stage tube group 7, an original economizer inlet header is connected to a feed water pipe as an inlet header of the economizer, an economizer intermediate header 6 is disposed between the economizer lower-stage tube group 7 and the economizer upper-stage tube group 8, an economizer bypass pipe 17 is disposed between the feed water pipe and the economizer intermediate header 6, and the new economizer tube group 14 is disposed in the economizer bypass pipe 17. However, the present invention is not limited to this, and the range of the bypass pipe group may be adjusted by adjusting the installation position of the economizer intermediate header 6.
According to the present invention, the new economizer tube group 14 may be placed in both the combined flue and the low-temperature reheater-side flue of the divided flue. Preferably, when the newly added economizer pipe group is arranged in series with at least two stages of economizer pipe groups, the newly added economizer pipe group is arranged in the combined flue; when the additional economizer pipe group and the economizer pipe group are arranged in parallel, the additional economizer pipe group is arranged in the side flue of the low-temperature reheater.
The newly added economizer pipe group 14, the economizer inlet header 13, the low-temperature reheater inlet header 1 and the bypassed low-temperature reheater horizontal pipe group in the invention need to select materials and specifications capable of being dried and burned according to the smoke temperature level. Because the smoke temperature of the area is low and the number of selectable materials is large, the conventional 91-grade and 12Cr1MoVG can be used as the selectable materials, and the cost is controllable.
In addition, the control valves of the present invention, such as the economizer bypass control valve 16, the low re-bypass control valve 19, the feed water pipe control valve 15, and the cold re-pipe control valve 18, may be in the form of butterfly valves, gate valves, or other valves, and the tube type of the economizer tube group may be in the form of a plain tube type or a finned tube type.
the invention also provides a control method of the steam extraction modification structure of the flue gas baffle plate-based temperature-regulating boiler.
according to an exemplary embodiment of the present invention, during the steam extraction mode, the horizontal stack of at least one low temperature reheater is taken out of operation by opening the low re-bypass control valve 19 and closing the cold re-channel control valve 18 and controlling the flow of reheated steam through the low re-bypass channel, and/or the economizer bypass control valve 16 is closed and the feed water channel control valve 15 is opened and the feed water flow through the new economizer stack 14 is controlled to take the new economizer stack into operation. When the new economizer pipe group and the economizer pipe group are arranged in parallel, under the steam extraction working condition, the economizer bypass control valve and the water supply pipeline control valve on the water supply pipeline are opened simultaneously, so that water supply flows through the new economizer pipe group and at least two stages of economizer pipe groups simultaneously
Taking the example shown in fig. 1, under the steam extraction working condition, the low re-bypass control valve 19 is opened and the cold re-pipeline control valve 18 is closed, and the reheated steam passes through the low re-bypass pipeline and is dried by the bypassed low-temperature reheater horizontal primary pipe group 2, and the actually put-in-service low-temperature reheater area only remains the low-temperature reheater horizontal secondary pipe group 3, the low-temperature reheater horizontal tertiary pipe group 4 and the low-temperature reheater vertical pipe group 5, so that the purpose of reducing the reheater area is achieved, the low re-side flue gas share is favorably kept in a reasonable range, and the adjustability of the low-temperature reheater side flue gas baffle 11 and the safety of the reheater are ensured.
Under the series working condition shown in fig. 1, the economizer bypass control valve 16 is closed, the water supply pipeline control valve 15 is opened, and the newly added economizer pipe group 14 forms a part of the whole economizer, which is equivalent to increase the heat exchange area of a primary steam system and can maintain the denitration inlet smoke temperature at the original design level.
Under the parallel working condition shown in fig. 2, the economizer bypass control valve 16 is opened, the water supply pipeline control valve 15 is opened, and the newly added economizer pipe group 14 forms a part of the whole economizer, which is equivalent to increase the heat absorption capacity of the front flue, and can maintain the denitration inlet smoke temperature at the original design level.
In the non-extraction condition, the low re-bypass control valve 19 is closed and the cold re-pipe control valve 18 is opened and the reheated steam is controlled not to flow through the low re-bypass pipe 20 so that all the horizontal pipe groups of the low temperature reheater are put into operation, and/or the economizer bypass control valve 16 is closed and the feed water pipe control valve 15 is opened and the feed water is controlled not to flow through the newly added economizer pipe group 14 so that the newly added economizer pipe group is taken out of operation.
Also taking fig. 1 as an example, the low-temperature bypass control valve 19 is closed, the cold-reheat pipeline control valve 18 is opened, reheat steam enters the low-temperature reheater inlet header 1, the low-temperature reheater horizontal primary tube group 2 is put into operation, and the low-temperature reheater returns to an original state, so that the condition that the steam temperature does not reach the standard is avoided.
Under the series working condition shown in fig. 1, the economizer bypass control valve 16 is opened, the water supply pipeline control valve 15 is closed, the newly added economizer pipe group 14 is dried, the economizer area is restored to the original state, and the unfavorable phenomena of economizer boiling and the like caused by too much economizer area in the operation process are avoided.
Under the parallel working condition shown in fig. 2, the economizer bypass control valve 16 is closed, the water supply pipeline control valve 15 is opened, the newly added economizer pipe group 14 is dried, the area of the economizer is restored to the original state, and the unfavorable phenomena of economizer boiling and the like caused by excessive area of the economizer in the operation process are avoided.
The present invention will be described with reference to specific examples.
The present embodiment adopts the structure shown in fig. 1. Under the steam extraction working condition, the horizontal primary pipe group 2 of the low-temperature reheater is cut off to reduce the area of the reheater, the share of the flue gas at the side of the low-temperature reheater can be maintained in an adjustable range, and the safety of the reheater is guaranteed; meanwhile, the newly added economizer pipe group 14 is put into operation to increase the area of the economizer, so that the temperature of the denitration inlet smoke can be maintained at the original level, and the reasonability of the denitration operation cost is ensured.
Table 2 below shows various data of the original design condition and the modified condition in this embodiment.
FIG. 2 is a comparison between the original design and the modified parameters of the present embodiment
According to table 2, the temperature rise of the high-temperature reheater is increased, which means that the temperature of the working medium at the inlet of the high-temperature reheater is reduced, the high re-deviation may be increased, and the deviation wall temperature may be increased, and the problem can be solved by upgrading the pipe; the low-secondary side flue gas share is maintained to be more than 30%, the adjusting performance of the flue gas adjusting baffle is guaranteed, and if the low-secondary side flue gas share needs to be further improved, the low-temperature reheater horizontal secondary pipe group 3 can be brought into a bypass range; the denitration inlet smoke temperature is basically maintained at the level equivalent to the original design (non-steam extraction working condition), and the denitration operation is not influenced.
Under the non-steam extraction working condition, the horizontal primary pipe group 2 of the low-temperature reheater is put into operation, so that the low-temperature reheater is ensured to have enough area and is restored to the original design state; the new economizer pipe group 14 is cut off, and the economizer area is restored to the original design state. The whole boiler is not different from the original design state except the dry burning of the newly added economizer pipe group 14, and can completely adapt to the original design working condition (non-steam extraction working condition).
Under the steam extraction working condition, the denitration entry smoke temperature maintains unchanged, and boiler efficiency can maintain unchanged, has guaranteed the economic nature of boiler.
In conclusion, the invention can simultaneously meet the steam extraction working condition and the non-steam extraction working condition, and simultaneously solves the problem of smoke temperature rise at the denitration inlet. Specifically, the low-level-re-level pipe group is switched and the area of a reheater put into operation is adjusted by arranging a bypass pipeline of the low-level-re-level pipe group, so that the method has adaptability to changes of reheated steam flow under two working conditions of steam extraction and non-steam extraction; the economizer pipe group can be switched by adding the economizer pipe group and arranging the economizer pipe group bypass pipe, the operating area of the economizer can be adjusted, and the adaptability to the denitration inlet smoke temperature and the economizer outlet working medium temperature under two working conditions of steam extraction and non-steam extraction is realized.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.
Claims (9)
1. A steam extraction transformation method based on a flue gas baffle temperature-regulating boiler is characterized in that a low-re-bypass pipeline and a low-re-bypass control valve which are connected with partial horizontal pipe groups of a low-temperature reheater in parallel are arranged in an original horizontal pipe group of the low-temperature reheater, and/or
The new economizer pipe set is added in the original economizer pipe set, the new economizer pipe set is connected with the original economizer pipe set in series or in parallel, an economizer bypass pipeline and an economizer bypass control valve are arranged, the water supply pipeline is connected with the new economizer pipe set when the new economizer pipe set is connected in series, and the water supply pipeline is connected with the original economizer pipe set when the new economizer pipe set is connected in parallel and the new economizer pipe set is arranged on the economizer bypass pipeline.
2. The steam extraction reforming method of a flue gas baffle attemperation boiler according to claim 1, characterized in that a low-temperature reheater intermediate header is added between any two horizontal tube groups of the original low-temperature reheater, a cold re-pipe connected to a low-temperature reheater inlet header is further connected to the low-temperature reheater intermediate header through a low re-bypass pipe, and a cold re-pipe control valve is provided on the cold re-pipe, and/or
When the newly added economizer pipe group is connected with the original economizer pipe group in series, the newly added economizer pipe group is arranged in the combined flue, an economizer inlet header connected with the newly added economizer pipe group is added, the original economizer inlet header is replaced by an economizer middle header, a water supply pipeline is connected with the economizer inlet header, a water supply pipeline control valve is arranged on the water supply pipeline, and an economizer bypass pipeline is connected with the economizer middle header;
When the newly added economizer pipe group is connected with the original economizer pipe group in parallel, a water supply pipeline control valve is arranged on a water supply pipeline connected with an inlet header of the original economizer, the newly added economizer pipe group is arranged in a low-secondary side flue, an intermediate header of the economizer is added between any two stages of the pipe groups of the original economizer, and an economizer bypass pipeline is connected with the intermediate header of the economizer through the newly added economizer pipe group.
3. the steam extraction reforming method of the flue gas baffle temperature-regulating boiler based on the claim 1 is characterized in that under the steam extraction working condition, reheated steam flows through a low-temperature bypass pipeline to enter a low-temperature reheater horizontal tube group which is not bypassed and/or feed water flows through a newly-added economizer tube group; under the non-steam extraction working condition, the reheated steam flows through the original low-temperature reheater horizontal tube group and/or the feed water flows through the original economizer tube group.
4. The utility model provides a structure is reformed transform to steam extraction based on flue gas baffle attemperation boiler which characterized in that, the low temperature reheater of arranging in flue gas baffle attemperation boiler's back shaft includes two-stage level nest of tubes at least and newly-increased low bypass pipeline, low bypass control valve and cold pipeline control valve again, low bypass pipeline links to each other and sets up in parallel with the horizontal nest of tubes of part of low temperature reheater with the middle collection case of low temperature reheater that sets up between arbitrary two-stage level nest of tubes again, cold pipeline again links to each other with low temperature reheater entry collection case, and/or
The economizer arranged in the rear shaft flue of the flue gas baffle temperature-regulating boiler comprises at least one-stage economizer pipe group, a newly-added economizer pipe group, an economizer bypass pipeline, an economizer bypass control valve and a water supply pipeline control valve, when the newly-added economizer pipe group is connected with the economizer pipe group in series, the water supply pipeline is connected with an inlet header of the newly-added economizer pipe group serving as an economizer inlet header, the economizer bypass pipeline is connected with the newly-added economizer pipe group in parallel and is connected with an economizer middle header or an economizer outlet header arranged between any two stages of economizer pipe groups;
When the newly added economizer pipe group and the economizer pipe group are arranged in parallel, the water supply pipeline is connected with the economizer inlet header, the economizer bypass pipeline is connected with the economizer middle header or the economizer outlet header arranged between any two stages of economizer pipe groups, and the newly added economizer pipe group is arranged on the economizer bypass pipeline and is arranged in parallel with part of the economizer pipe groups.
5. The steam extraction transformation structure based on the flue gas baffle temperature-adjusting boiler is characterized in that the rear vertical shaft of the flue gas baffle temperature-adjusting boiler at least comprises double flues, a low-temperature reheater is arranged in the front flue, a low-temperature superheater and an economizer are arranged in the rear flue, and the temperature of the reheated steam is adjusted through the flue gas baffle below the flues.
6. The steam extraction modification structure of the flue gas baffle temperature regulating boiler according to claim 4, wherein each control valve is a butterfly valve or a gate valve, and the tube type of the economizer tube group is a plain tube type or a finned tube type.
7. The steam extraction modification structure of the flue gas baffle temperature-regulating boiler according to claim 4, wherein when an additional economizer pipe group is arranged in series with the economizer pipe group, the additional economizer pipe group is arranged in the combined flue; when the additional economizer pipe group and the economizer pipe group are arranged in parallel, the additional economizer pipe group is arranged in the side flue of the low-temperature reheater.
8. The method for controlling the steam extraction reforming structure of the flue gas baffle temperature-regulating boiler according to any one of claims 4 to 7, wherein in the steam extraction condition, the low re-bypass control valve is opened, the cold re-pipe control valve is closed, and the reheated steam is controlled to flow through the low re-bypass pipe so that the horizontal pipe set of the at least one low temperature reheater is removed from operation, and/or when the new economizer pipe set is arranged in series with the economizer pipe set, the economizer bypass control valve is closed and the water supply pipe control valve is opened, and the water supply flow is controlled to flow through the new economizer pipe set so that the new economizer pipe set is put into operation;
And/or when the newly added economizer pipe group is connected with the economizer pipe group in series, the economizer bypass control valve is opened, the water supply pipe control valve is closed, and the water supply is controlled not to flow through the newly added economizer pipe group so that the newly added economizer pipe group is withdrawn from operation.
9. The method for controlling the steam extraction reforming structure of the flue gas baffle temperature regulating boiler according to claim 8, wherein when the additional economizer pipe set and the economizer pipe set are arranged in parallel, under the steam extraction working condition, the economizer bypass control valve and the water supply pipeline control valve on the water supply pipeline are simultaneously opened to enable water supply to simultaneously flow through the additional economizer pipe set and the at least one stage of economizer pipe set; and under the non-steam extraction working condition, closing the economizer bypass control valve, opening the water supply pipeline control valve and controlling the feed water not to flow through the newly added economizer pipe group so as to enable the newly added economizer pipe group to quit the operation.
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| CN114754345A (en) * | 2022-04-24 | 2022-07-15 | 西安热工研究院有限公司 | Boiler and thermal power generating unit with baffle plate assembly |
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