Boiler flue gas baffle system and overall adjustment and partition control method thereof
By setting up an independently adjustable local baffle structure in the boiler flue gas damper system, combined with overall adjustment and zone control methods, the problem of controlling reheat steam temperature and wall temperature in secondary reheat units was solved, achieving the improvement of reheat steam temperature and the balance of wall temperature, thereby improving unit efficiency and safety.
Patent Information
- Application Number
- CN202511708894.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-02-06
AI Technical Summary
During operation, reheat units have the problem that the reheat steam temperature does not reach the design value. In addition, due to design or manufacturing process issues, the wall temperature of the high-temperature heating surface in some areas of domestic units is relatively high, which limits the control of steam temperature.
Design a boiler flue gas damper system, including a low-temperature superheater, a primary low-temperature reheater, and a secondary low-temperature reheater. Set up an independently adjustable local damper structure, and regulate the flue gas flow rate to control the steam temperature and wall temperature through overall adjustment and zone control methods.
It effectively improved the reheat steam temperature level, reduced the amount of desuperheating water used, balanced the wall temperature distribution, avoided the limitation of reheat steam temperature due to local high temperature, and improved the unit efficiency and safety.
Smart Images
Figure CN121474545A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of power plant boilers, in particular to a boiler flue gas baffle system, an overall adjustment method of the boiler flue gas baffle system, and a zoned control method of the boiler flue gas baffle system. BACKGROUND
[0002] In the future for a considerable period of time, coal power generation will still be the main form of power generation in China, in order to reduce the proportion of coal consumption, it is necessary to steadily promote the clean and efficient conversion and utilization of coal energy. After years of development and exploration, coal-fired efficient combustion and advanced power generation technology has made certain development. The related technology mainly reflects in improving the steam parameters of the unit, adopting reheat cycle and increasing the number of reheating to improve the efficiency of the unit and thus reduce the coal consumption for power generation. Under this background, supercritical and ultra-supercritical coal-fired power generating units are continuously developed. At the same time, in order to continue to improve the power generation efficiency of the current ultra-supercritical unit, the current high-parameter unit generally adopts the secondary reheat technology to solve the efficient utilization of coal.
[0003] The control and adjustment of the reheating steam temperature of the secondary reheat unit is more complex and difficult than that of the conventional primary reheat unit. Some foreign secondary reheat units that have been put into operation often have problems that the primary and secondary reheating steam temperatures cannot reach the design values during operation. At present, the reheating steam temperature of the secondary reheat unit mainly adopts flue gas recirculation and tail flue gas baffle as the main adjustment mode, and each mode can make the reheater absorb enough heat, but at present, due to design or manufacturing process problems, the wall temperature of the high-temperature heating surface in some areas is relatively high, thereby limiting the control of the steam temperature. SUMMARY
[0004] The purpose of the present application is to provide a boiler flue gas baffle system, an overall adjustment method thereof, and a zoned control method thereof, to solve the problems raised in the background technology.
[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions: A boiler flue gas baffle system, comprising a low-temperature superheater, a primary low-temperature reheater, and a secondary low-temperature reheater; The outlet flue of the low-temperature superheater, the primary reheater, and the secondary reheater is respectively provided with an independently adjustable local baffle structure; the local baffle structure comprises: a superheated flue gas baffle group arranged downstream of the low-temperature superheater; a primary flue gas baffle group arranged downstream of the primary low-temperature reheater; and a secondary flue gas baffle group arranged downstream of the secondary low-temperature reheater.
[0006] Preferably, upstream of the low-temperature superheater, the primary low-temperature reheater, and the secondary low-temperature reheater, there are arranged, in sequence along the flue gas flow direction, a high-temperature superheater, a primary high-temperature reheater, and a secondary high-temperature reheater.
[0007] Preferably, a desuperheating water regulating valve is arranged in the intermediate pipeline between the first low-temperature reheater and the first high-temperature reheater, and a second desuperheating water regulating valve is arranged in the intermediate pipeline between the second low-temperature reheater and the first high-temperature reheater.
[0008] Preferably, the superheating flue gas baffle group, the first reheating flue gas baffle group, and the second reheating flue gas baffle group are each composed of a plurality of baffle assemblies.
[0009] Preferably, the local baffle structure is provided below with an economizer.
[0010] A method for overall adjustment of a boiler flue gas baffle system, which adopts the boiler flue gas baffle system of any one of claims 1-6, comprises the following steps: S1: judging whether there is desuperheating water in the first low-temperature reheater based on the opening degree of the first desuperheating water regulating valve, and judging whether there is desuperheating water in the second low-temperature reheater based on the opening degree of the second desuperheating water regulating valve; S2: if there is no desuperheating water in the first low-temperature reheater, judging whether the first reheating steam temperature is over-temperature, under-temperature, or appropriate relative to the set value; if there is no desuperheating water in the second low-temperature reheater, judging whether the second reheating steam temperature is over-temperature, under-temperature, or appropriate relative to the set value; S3: adjusting the opening degrees of the superheating flue gas baffle group, the first reheating flue gas baffle group, and the second reheating flue gas baffle group according to the results of steps S1 and S2.
[0011] Preferably, in step S3, the adjustment of the first reheating flue gas baffle group and the second reheating flue gas baffle group comprises: for the reheater with desuperheating water, closing the corresponding reheater flue gas baffle by a preset opening degree value; for the reheater without desuperheating water and with under-temperature steam, opening the corresponding reheater flue gas baffle by a preset opening degree value; for the reheater without desuperheating water and with appropriate steam temperature, keeping the opening degree of the corresponding reheater flue gas baffle unchanged; for the reheater without desuperheating water and with over-temperature steam, closing the corresponding reheater flue gas baffle by a preset opening degree value.
[0012] Preferably, after the adjustment of the first reheating flue gas baffle group and the second reheating flue gas baffle group is performed, the opening degree of the superheating flue gas baffle group is adjusted synchronously so that the sum of the opening degrees of the superheating flue gas baffle group, the first reheating flue gas baffle group, and the second reheating flue gas baffle group is maintained constant.
[0013] A method for zonal control of a boiler flue gas baffle system, which adopts the boiler flue gas baffle system of any one of claims 1-6, comprises the following steps: S1a: counting the high-temperature heating surface wall temperature peak values of each zone of the boiler; S2a: comparing the wall temperature peak values of each zone with a preset limit temperature to judge whether there is a zone with wall temperature over-limit; S3a: if the result of step S2a is yes, closing the preset opening degree value of the baffle assembly corresponding to the zone with wall temperature over-limit.
[0014] Compared with the prior art, the application proposes a flue gas baffle control method through the steam temperature at each stage and the desuperheating water parameters, which not only considers the steam temperature at each stage, but also considers the desuperheating water, in the case of the desuperheating water of the reheater, the reheater baffle is actively closed to reduce the desuperheating water consumption and improve the unit efficiency; in the case of the excessive or insufficient desuperheating water of the superheater, the superheater baffle is locked to prevent the superheated steam temperature from being out of adjustment, and the safety of the superheated steam temperature is ensured.
[0015] In addition, the application proposes a zoning control strategy, the flue gas baffle is controlled by zoning to control the flue gas flow, so as to adjust the wall temperature, reduce the wall temperature deviation in different regions, and avoid the limitation of the reheated steam temperature due to the high local wall temperature, and effectively improve the reheated steam temperature. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 It is a schematic diagram of the boiler flue gas flow of the application; Figure 2 It is a schematic diagram of the boiler tail flue gas baffle arrangement of the application.
[0017] In the figure: 1, low-temperature superheater; 2, primary low-temperature reheater; 3, secondary low-temperature reheater; 4, local baffle structure; 401, superheated flue gas baffle group; 402, primary flue gas baffle group; 403, secondary flue gas baffle group; 5, high-temperature superheater; 6, primary high-temperature reheater; 7, secondary high-temperature reheater; 8, primary desuperheating water regulating valve; 9, secondary desuperheating water regulating valve; 10, baffle assembly; 11, economizer. DETAILED DESCRIPTION
[0018] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.
[0019] In the description of the application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.
[0020] In the description of the present patent, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "arrange" should be understood in a broad sense, for example, it can be fixedly connected, arranged, or detachably connected, arranged, or integrally connected, arranged. For those skilled in the art, the specific meaning of the above terms in the present patent can be understood according to the specific circumstances.
[0021] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "several" is two or more, unless otherwise explicitly specified and limited.
[0022] Embodiment Please refer to Figures 1-2 As shown in the drawings, the present application provides a boiler flue baffle system, which comprises a low-temperature superheater 1, a first low-temperature reheater 2 and a second low-temperature reheater 3. Upstream of the low-temperature superheater 1, the first low-temperature reheater 2 and the second low-temperature reheater 3, there are arranged, in sequence along the flue gas flow direction, a high-temperature superheater 5, a first high-temperature reheater 6 and a second high-temperature reheater 7.
[0023] The outlet flue of the low-temperature superheater 1, the first low-temperature reheater 2 and the second low-temperature reheater 3 is respectively provided with an independently adjustable local baffle structure 4.
[0024] A desuperheating water regulating door 8 is arranged in the pipeline between the first low-temperature reheater 2 and the first high-temperature reheater 6, a second desuperheating water regulating door 9 is arranged in the pipeline between the second low-temperature reheater 3 and the first high-temperature reheater 6, and a coal economizer 11 is arranged below the local baffle structure 4.
[0025] It should be noted that the desuperheating water regulating door can also be arranged at other appropriate positions, for example, between the high-temperature superheater 5 and the low-temperature superheater 1.
[0026] In the present embodiment, the local baffle structure 4 comprises: a superheated flue gas baffle group 401, a first desuperheating flue gas baffle group 402 and a second desuperheating flue gas baffle group 403. Among them, the superheated flue gas baffle group 401 is arranged downstream of the low-temperature superheater 1; the first desuperheating flue gas baffle group 402 is arranged downstream of the first low-temperature reheater 2; and the second desuperheating flue gas baffle group 403 is arranged downstream of the second low-temperature reheater 3.
[0027] For ease of understanding, the overall arrangement is shown in Figure 1 , in which A, C, D three reference directions are given, wherein the A direction is the direction from the front end of the boiler to the rear end of the boiler, the C direction is the direction from the top end of the boiler to the bottom end of the boiler, and the D direction is the direction of flue gas flow.
[0028] As shown in Figure 2 each of the superheated flue gas damper group 401, the primary reheated flue gas damper group 402 and the secondary reheated flue gas damper group 403 is composed of a plurality of damper assemblies 10, each of which includes an actuator and at least one damper, of course, in another case, a plurality of dampers can also be synchronously driven by one actuator.
[0029] In this embodiment, each damper group contains 6 damper assemblies 10. In order to further show the arrangement, A and B reference directions are marked in the figure, where the A direction is from the front end of the boiler to the rear end of the boiler, and the B direction is from the left side of the boiler to the right side of the boiler.
[0030] The embodiment also provides a whole adjustment method of a boiler flue gas damper system, which adopts the above boiler flue gas damper system and includes the following steps: S1: judging whether there is desuperheating water in the primary low-temperature reheater 2 based on the opening of the primary desuperheating water damper 8, and judging whether there is desuperheating water in the secondary low-temperature reheater 3 based on the opening of the secondary desuperheating water damper 9; S2: if there is no desuperheating water in the primary low-temperature reheater 2, judging whether the primary reheated steam temperature is over-temperature, under-temperature or appropriate temperature relative to the set value, and if there is no desuperheating water in the secondary low-temperature reheater 3, judging whether the secondary reheated steam temperature is over-temperature, under-temperature or appropriate temperature relative to the set value; S3: adjusting the opening of the superheated flue gas damper group 401, the primary reheated flue gas damper group 402 and the secondary reheated flue gas damper group 403 according to the judgment results of the step S1 and the step S2.
[0031] In the step S1, when the opening of the primary desuperheating water damper 8 and the secondary desuperheating water damper 9 is ≤3%, it is determined that there is no desuperheating water, otherwise, it is determined that there is desuperheating water.
[0032] In the step S2, the primary reheated steam temperature and the secondary reheated steam temperature are appropriate temperature within ±3℃ deviation from the set value, over-temperature when exceeding +3℃, and under-temperature when being lower than -3℃.
[0033] In the step S3, the adjustment of the primary reheated flue gas damper group 402 and the secondary reheated flue gas damper group 403 includes: for the reheater with desuperheating water, closing the reheater flue gas damper corresponding to the reheater by a preset opening value; for the reheater without desuperheating water and with under-temperature, opening the reheater flue gas damper corresponding to the reheater by a preset opening value; for the reheater without desuperheating water and with appropriate temperature, keeping the opening of the reheater flue gas damper corresponding to the reheater unchanged; for the reheater without desuperheating water and with over-temperature, closing the reheater flue gas damper corresponding to the reheater by a preset opening value.
[0034] In the above adjustment, the preset opening degree value of opening or closing is 2% of the maximum opening degree of each flue gas damper group.
[0035] In step S3, the specific adjustment logic of the first reheat flue gas damper group 402 and the second reheat flue gas damper group 403 is as follows: If both the first low-temperature reheater 2 and the second low-temperature reheater 3 exist desuperheating water, step S2 is skipped, and both the first reheat flue gas damper group 402 and the second reheat flue gas damper group 403 are closed by 2% of the maximum opening degree; If the first low-temperature reheater 2 exists desuperheating water and the second low-temperature reheater 3 does not exist desuperheating water, the first reheat flue gas damper group 402 is closed by 2% of the maximum opening degree; and the second reheat flue gas damper group 403 is adjusted according to the second reheat steam temperature: if the temperature is insufficient, the second reheat flue gas damper group 403 is opened by 2% of the maximum opening degree; if the temperature is appropriate, the second reheat flue gas damper group 403 is kept unchanged; and if the temperature is excessive, the second reheat flue gas damper group 403 is closed by 2% of the maximum opening degree; If the first low-temperature reheater 2 does not exist desuperheating water and the second low-temperature reheater 3 exists desuperheating water, the second reheat flue gas damper group 403 is closed by 2% of the maximum opening degree; and the first reheat flue gas damper group 402 is adjusted according to the first reheat steam temperature: if the temperature is insufficient, the first reheat flue gas damper group 402 is opened by 2% of the maximum opening degree; if the temperature is appropriate, the first reheat flue gas damper group 402 is kept unchanged; and if the temperature is excessive, the first reheat flue gas damper group 402 is closed by 2% of the maximum opening degree; If both the first low-temperature reheater 2 and the second low-temperature reheater 3 do not exist desuperheating water, the corresponding flue gas damper group is independently adjusted according to the first reheat steam temperature and the second reheat steam temperature: if the temperature is insufficient, the flue gas damper group is opened by 2% of the maximum opening degree; if the temperature is appropriate, the flue gas damper group is kept unchanged; and if the temperature is excessive, the flue gas damper group is closed by 2% of the maximum opening degree.
[0036] After the adjustment of the first reheat flue gas damper group 402 and the second reheat flue gas damper group 403 is performed, the opening degree of the superheated flue gas damper group 401 is simultaneously adjusted so that the sum of the opening degrees of the superheated flue gas damper group 401, the first reheat flue gas damper group 402 and the second reheat flue gas damper group 403 is kept constant.
[0037] The specific adjustment logic is as follows: If both the first reheat flue gas damper group 402 and the second reheat flue gas damper group 403 are opened by 2% of the maximum opening degree, the superheated flue gas damper group 401 is closed by 4% of the maximum opening degree; If one of the first reheat flue gas damper group 402 and the second reheat flue gas damper group 403 is opened by 2% of the maximum opening degree, the superheated flue gas damper group 401 is closed by 2% of the maximum opening degree; If one of the first reheat flue gas damper group 402 and the second reheat flue gas damper group 403 is closed by 2% of the maximum opening degree, the superheated flue gas damper group 401 is opened by 2% of the maximum opening degree; If both the first reheat flue gas damper group 402 and the second reheat flue gas damper group 403 are closed by 2% of the maximum opening degree, the superheated flue gas damper group 401 is opened by 4% of the maximum opening degree.
[0038] In order to further ensure the safety in the adjustment process of the reheated steam temperature, the above adjustment control simultaneously exists the following locking conditions: When the opening degree of the superheater gas damper group 401 + the opening degree of the primary reheater gas damper group 402 + the opening degree of the secondary reheater gas damper group 403 ≤ 150%, the closing instruction of any damper is prohibited; When the average opening degree of the desuperheating water regulating valve ≤ 10%, the closing instruction of the superheater gas damper group 401 is prohibited; When the average opening degree of the desuperheating water regulating valve > 70%, the opening instruction of the superheater gas damper group 401 is prohibited; When the opening degree of any damper group < 20%, the closing instruction of the damper group is prohibited.
[0039] The opening degree of the above damper group is the average value of the opening degrees of the six damper components 10 thereof, and the average opening degree of the desuperheating water regulating valve is the average value of all the opening degrees of the desuperheating water regulating valve. In addition, considering that the response delay of the boiler system is large, in order to avoid frequent action of the gas damper, the overall adjustment control period is set to 3 minutes.
[0040] The embodiment also provides a partition control method of a boiler gas damper system.
[0041] As described above, the superheater gas damper group 401, the primary reheater gas damper group 402 and the secondary reheater gas damper group 403 are each composed of a plurality of (same number) independent damper components 10 and are arranged side by side along the furnace width direction (from the left of the furnace to the right of the furnace) in sequence. Taking the number n of the damper components 10 of a single gas damper group as a reference, the high-temperature heating surface (i.e. the high-temperature superheater 5, the primary high-temperature reheater 6 and the secondary high-temperature reheater 7) is divided into n gas partitions in the horizontal width direction, so as to realize independent controllability of the gas flow of each partition.
[0042] The above boiler gas damper system is adopted, comprising the following steps: S1a: counting the peak wall temperature of the high-temperature heating surface of each partition of the boiler; S2a: comparing the peak wall temperature of each partition with the preset limit temperature to determine whether there is a partition with wall temperature exceeding the limit; S3a: if the determination result of step S2 is yes, the preset opening degree value of the damper component 10 corresponding to the wall temperature exceeding the limit partition (i.e. the damper component 10 of the corresponding superheater, primary reheater and secondary reheater) is closed.
[0043] In order to ensure the safety of the gas damper adjustment, the following locking conditions are set for the partition control: The opening degree deviation (deviation from the average value) of any single damper component 10 cannot exceed ±20%, and the opening degree of the single gas damper group is not less than 10%.
[0044] In view of the large response delay of the boiler, in order to avoid frequent action of the damper, the scanning period of the partition control is set to 3 minutes.
[0045] It should be noted that the above overall adjustment method and partition control method can be automatically executed by the system, or can be manually intervened according to actual conditions.
[0046] By means of the boiler flue gas baffle system combined with the overall adjustment method, the opening degree of each flue gas baffle group can be actively adjusted according to the steam temperature at each stage and the desuperheating water parameter, the desuperheating water consumption is reduced, and the unit efficiency is improved; at the same time, by means of the partition control mechanism, the flue gas flow is accurately adjusted to balance the wall temperature distribution, reduce the regional wall temperature deviation, and avoid the limitation of the reheated steam temperature due to local high temperature, so that the reheated steam temperature level is effectively improved.
[0047] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above examples, and the above examples and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.
Claims
1. A boiler flue gas damper system, characterized in that: It includes a low-temperature superheater, a primary low-temperature reheater, and a secondary low-temperature reheater; the outlet flues of the low-temperature superheater, the primary reheater, and the secondary reheater are each equipped with an independently adjustable local baffle structure; the local baffle structure includes: a superheated flue gas baffle group, located downstream of the low-temperature superheater; a primary reheated flue gas baffle group, located downstream of the primary low-temperature reheater; and a secondary reheated flue gas baffle group, located downstream of the secondary low-temperature reheater.
2. The boiler flue gas damper system according to claim 1, characterized in that: Upstream of the low-temperature superheater, the primary low-temperature reheater, and the secondary low-temperature reheater, a high-temperature superheater, a primary high-temperature reheater, and a secondary high-temperature reheater are arranged sequentially along the flue gas flow direction.
3. The boiler flue gas damper system according to claim 1, characterized in that: The intermediate pipeline between the primary low-temperature reheater and the primary high-temperature reheater is equipped with a reheating water regulating valve, and the intermediate pipeline between the secondary low-temperature reheater and the primary high-temperature reheater is equipped with two reheating water regulating valves.
4. The boiler flue gas damper system according to claim 1, characterized in that: The superheated flue gas damper group, the primary flue gas damper group, and the secondary flue gas damper group are all composed of several damper assemblies.
5. The boiler flue gas damper system according to claim 1, characterized in that: An economizer is located below the partial baffle structure.
6. A method for overall adjustment of a boiler flue gas damper system, characterized in that: The boiler flue gas damper system, including any one of claims 1-5, comprises the following steps: S1: Based on the opening of the primary reheating water regulating valve, determine whether there is deheating water in the primary low-temperature reheater; based on the opening of the secondary reheating water regulating valve, determine whether there is deheating water in the secondary low-temperature reheater; S2: If there is no deheating water in the primary low-temperature reheater, determine whether the primary reheat steam temperature is above, below, or suitable relative to its set value; if there is no deheating water in the secondary low-temperature reheater, determine whether the secondary reheat steam temperature is above, below, or suitable relative to its set value; S3: Adjust the opening of the superheated flue gas damper group, the primary reheating flue gas damper group, and the secondary reheating flue gas damper group according to the determination results of steps S1 and S2.
7. The overall adjustment method for the boiler flue gas damper system according to claim 6, characterized in that: In step S3, the adjustment of the primary and secondary reheat flue gas damper groups includes: for reheaters with desuperheating water, reducing the preset opening value of the corresponding reheater flue gas damper; for reheaters without desuperheating water and with insufficient steam temperature, increasing the preset opening value of the corresponding reheater flue gas damper; for reheaters without desuperheating water and with suitable steam temperature, keeping the opening value of the corresponding reheater flue gas damper unchanged; and for reheaters without desuperheating water and with excessive steam temperature, reducing the preset opening value of the corresponding reheater flue gas damper.
8. The overall adjustment method for the boiler flue gas damper system according to claim 7, characterized in that: After adjusting the primary and secondary flue gas damper groups, the opening of the superheated flue gas damper group is adjusted simultaneously to keep the sum of the openings of the superheated flue gas damper group, the primary flue gas damper group, and the secondary flue gas damper group constant.
9. A method for zoned control of boiler flue gas dampers, characterized in that: The boiler flue gas damper system, including any one of claims 1-5, comprises the following steps: S1a: statistically analyzing the peak wall temperature of the high-temperature heating surface of each zone of the boiler; S2a: comparing the peak wall temperature of each zone with a preset limit temperature to determine whether there is a zone with an excessive wall temperature; S3a: if the determination result of step S2a is yes, then reducing the preset opening value of the damper assembly corresponding to the zone with the excessive wall temperature.