A method for actively suppressing overheating of boiler wall temperature

Abstract

The present application provides a method for actively suppressing overtemperature of boiler wall temperature. It includes: dividing multiple wall temperature measuring points into regions to obtain multiple temperature regions according to the temperature influence of each cooling water on multiple wall temperature measuring points of the boiler heating surface; obtaining the actual maximum wall temperature of the wall temperature measuring points in each temperature region among the multiple temperature regions at the current moment; predicting and obtaining the predicted maximum wall temperature of each temperature region at the next moment based on the actual maximum wall temperature of each temperature region and the change characteristics of the corresponding steam temperature; obtaining the wall temperature weighted value according to the predicted maximum wall temperature of each temperature region and the preset weighted value; and actively suppressing the wall temperature overtemperature by coal-water synergy based on the wall temperature weighted value; actively suppressing the wall temperature overtemperature by cooling water synergy based on the predicted maximum wall temperature of each temperature region and the wall temperature alarm value. This scheme can effectively reduce the phenomenon of overtemperature of boiler wall temperature and ensure the safe and stable operation of each heating surface of the boiler.

Description

Technical Field

[0001] The present application relates to the technical field of industrial process control, and in particular to a method for actively suppressing overtemperature of a boiler wall. Background Art

[0002] Thermal stress damage, rupture or even bursting of boiler heating surfaces are the most common and widespread forms of unplanned shutdown of generator sets. Especially in the case of frequent peak load and frequency regulation of generator sets, the damage to boiler heating surfaces will be seriously aggravated, affecting the safe and economical operation of generator sets. Especially for ultra-supercritical units (see Figure 1 ), there is no steam drum as a buffer for the working fluid-energy balance, the feed water control cannot be independent, and the heating, phase change and superheating process of the working fluid are completed at one time, which seriously increases the risk of boiler overheating and tube burst. Therefore, it is necessary to study a solution that can suppress the overheating of the boiler wall temperature, which is of great significance to reduce the frequency of overheating of the wall temperature of supercritical units and ensure the safe and stable operation of the boiler heating surface. Summary of the invention

[0003] The present application provides a method for actively suppressing overheating of boiler wall temperature to reduce the problem of overheating of the wall temperature. The technical solution of the present application is as follows:

[0004] In a first aspect, an embodiment of the present application provides a method for actively suppressing overtemperature of a boiler wall temperature, comprising:

[0005] According to the temperature influence of each cooling water channel on the multiple wall temperature measuring points of the boiler heating surface, the multiple wall temperature measuring points are divided into regions to obtain multiple temperature regions;

[0006] Obtaining the maximum actual wall temperature of a wall temperature measuring point in each of the multiple temperature zones at the current moment;

[0007] Based on the actual maximum wall temperature of each temperature zone and the change characteristics of the corresponding steam temperature, predict and obtain the predicted maximum wall temperature of each temperature zone at the next moment;

[0008] Obtaining a wall temperature weighted value according to the predicted maximum wall temperature of each temperature zone and a preset weighted value; and actively suppressing wall temperature overheating in a coal-water synergistic manner based on the wall temperature weighted value;

[0009] Based on the predicted maximum wall temperature and the wall temperature alarm value of each temperature zone, a cooling water synergistic method is adopted to actively suppress wall temperature overheating.

[0010] In some embodiments, according to the temperature influence of each cooling water on multiple wall temperature measuring points of the boiler heating surface, the multiple wall temperature measuring points are divided into regions to obtain multiple temperature regions, including:

[0011] Determine the temperature influence of each cooling water channel on the multiple wall temperature measuring points according to the installation positions of the multiple wall temperature measuring points;

[0012] According to the temperature influence of each channel of cooling water on the multiple wall temperature measuring points, the multiple wall temperature measuring points are divided into regions to obtain multiple temperature regions.

[0013] In some embodiments, obtaining the actual maximum wall temperature of the wall temperature measuring point in each temperature zone of the multiple temperature zones at the current moment includes:

[0014] Acquire multiple actual wall temperature values ​​of multiple wall temperature measuring points in each temperature zone at the current moment;

[0015] The maximum value among the multiple actual wall temperature values ​​is taken as the maximum actual wall temperature of the temperature zone.

[0016] In some embodiments, the predicting the predicted maximum wall temperature of each temperature zone at the next moment based on the actual maximum wall temperature of each temperature zone and the change characteristics of the corresponding steam temperature includes:

[0017] Extracting the change rate of the steam temperature corresponding to each temperature zone through multi-level differentiation;

[0018] The rate of change of the steam temperature is multiplied by the prediction time and then added to the actual maximum wall temperature of the corresponding temperature zone to obtain the predicted maximum wall temperature of each temperature zone.

[0019] In some embodiments, the step of obtaining a wall temperature weighted value according to the predicted maximum wall temperature of each temperature zone and a preset weighted value comprises:

[0020] The predicted maximum wall temperature of each temperature zone is multiplied by the corresponding preset weighted value and then summed to obtain a wall temperature weighted value.

[0021] In some embodiments, the multiplying the predicted maximum wall temperature of each temperature zone by the corresponding preset weighted value and then summing them to obtain the wall temperature weighted value includes:

[0022] Comparing the predicted maximum wall temperatures corresponding to the temperature zones to obtain a comparison result;

[0023] According to the comparison result, matching the predicted maximum wall temperature of each temperature zone with a corresponding preset weighted value;

[0024] The predicted maximum wall temperature of each temperature zone is multiplied by a matching preset weighted value and then summed to obtain a wall temperature weighted value.

[0025] In some embodiments, actively suppressing wall temperature over-temperature by coal-water synergy based on the wall temperature weighted value includes:

[0026] Determining whether the wall temperature weighted value and the wall temperature alarm value satisfy a first preset relationship;

[0027] When the wall temperature weighted value and the wall temperature alarm value satisfy a first preset relationship, the amount of coal and water added to the combustion system is corrected by the boiler control system according to a preset function to actively suppress over-temperature of the wall temperature.

[0028] In some embodiments, the determining whether the wall temperature weighted value and the wall temperature alarm value satisfy a first preset relationship includes:

[0029] Calculating the difference between the wall temperature weighted value and the wall temperature alarm value;

[0030] Determine whether the difference is greater than the wall temperature over-limit margin, and obtain a determination result;

[0031] According to the judgment result, it is judged whether the wall temperature weighted value and the wall temperature alarm value satisfy a first preset relationship.

[0032] In some embodiments, after actively suppressing wall temperature over-temperature by coal-water synergy based on the wall temperature weighted value, the method further includes:

[0033] When the wall temperature weighted value and the wall temperature alarm value do not satisfy the first preset relationship, the boiler control system restores the original coal and water addition amounts of the combustion system.

[0034] In some embodiments, the method of actively suppressing wall temperature over-temperature by using cooling water in coordination based on the predicted maximum wall temperature of each temperature zone and the wall temperature alarm value includes:

[0035] When the predicted maximum wall temperature of each temperature zone and the wall temperature alarm value satisfy a second preset relationship, a cooling water synergistic method is used to actively suppress over-temperature of the wall.

[0036] In some embodiments, when the predicted maximum wall temperature of each temperature zone and the wall temperature alarm value satisfy a second preset relationship, actively suppressing the wall temperature overtemperature by using a cooling water collaborative method includes:

[0037] Calculate the difference between the predicted maximum wall temperature of each temperature zone and the wall temperature alarm value to obtain the wall temperature difference;

[0038] Calculate the difference between the actual steam temperature value of the desuperheating water path corresponding to each temperature zone and the corresponding steam temperature set value to obtain the steam temperature difference;

[0039] The positive and negative parts of the steam temperature difference and the positive part of the wall temperature difference are respectively formed by limiting;

[0040] determining the greater of a positive portion of the steam temperature difference and a positive portion of the wall temperature difference;

[0041] Calculate the sum of the larger value and the negative value of the steam temperature difference to obtain a temperature deviation;

[0042] Based on the temperature deviation, the controller of the desuperheating water system generates the desuperheating valve opening of the desuperheating water in the corresponding path of each temperature zone;

[0043] The corresponding cooling valve is controlled according to the cooling valve opening, so as to actively suppress the wall temperature overheating in coordination with the cooling water.

[0044] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0045] Active suppression of wall temperature overheating through the coordinated use of coal and water can achieve coarse adjustment of active suppression of wall temperature overheating, so that the wall temperature of each temperature zone is generally controlled within the adjustable range of cooling water; real-time prediction of the maximum wall temperature of each temperature zone at a future moment can enable active suppression of wall temperature overheating and advance adjustment, reduce the overadjustment of wall temperature overheating, and be beneficial to the stable operation of the wall temperature of the boiler heating surface; combined with the active suppression of wall temperature overheating through the coordinated use of cooling water, fine adjustment of active suppression of wall temperature overheating in each temperature zone can be achieved, so that the wall temperature of each temperature zone reaches its respective optimal operating state; this scheme can effectively reduce the phenomenon of boiler wall temperature overheating and ensure the safe and stable operation of each heating surface of the boiler.

[0046] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application, and do not constitute an improper limitation on the present application.

[0048] Figure 1 It is a schematic diagram of the process of an ultra-supercritical unit.

[0049] Figure 2 It is a flow chart of a method for actively suppressing boiler wall overtemperature shown in an embodiment of the present application.

[0050] Figure 3 It is a three-dimensional schematic diagram of the high-temperature superheater.

[0051] Figure 4 It is a block diagram of the wall temperature real-time prediction principle shown in an embodiment of the present application.

[0052] Figure 5 It is a flow chart of a method for obtaining a wall temperature weighted value suitable for active suppression of coal and water, shown in an embodiment of the present application.

[0053] Figure 6 It is a block diagram of the principle of active suppression of wall temperature over-temperature by coal and water shown in an embodiment of the present application.

[0054] Figure 7 It is a block diagram of the principle of actively suppressing wall temperature overheating by cooling water shown in an embodiment of the present application.

[0055] In the figure:

[0056] 1- boiler, 2- generator, 3- turbine, 4- condenser, 5- feed water pump, 6- main steam valve, 7- bypass valve, 8- reheat desuperheater, 9- high temperature desuperheater, 10- wall temperature measuring point, 11- desuperheater, 12- temperature zone. DETAILED DESCRIPTION

[0057] In order to enable ordinary persons in the art to better understand the technical solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0058] It should be noted that the terms "first", "second", etc. in this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the application described here can be implemented in an order other than those illustrated or described here. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0059] Figure 2 FIG. 1 is a flow chart showing a method for actively suppressing overtemperature of a boiler wall temperature according to an exemplary embodiment. Figure 2 The method for actively suppressing overtemperature of boiler wall temperature may include the following steps:

[0060] S101, according to the temperature influence of each channel of desuperheating water on multiple wall temperature measuring points of the boiler heating surface, the multiple wall temperature measuring points are divided into regions to obtain multiple temperature regions.

[0061] In a specific embodiment of the present application, multiple wall temperature measurement points of the boiler heating surface are divided into respective areas, and the division is based on the influence of each cooling water channel on each wall temperature measurement point of the boiler heating surface.

[0062] As a possible implementation method, a method for dividing the multiple wall temperature measuring points into regions includes: determining the temperature influence of each cooling water channel on the multiple wall temperature measuring points according to the installation positions of the multiple wall temperature measuring points; and dividing the multiple wall temperature measuring points into regions according to the temperature influence of each cooling water channel on the multiple wall temperature measuring points to obtain multiple temperature regions.

[0063] In other words, by analyzing the influence characteristics of each cooling water on each wall temperature measuring point of the boiler heating surface, the wall temperature measuring points of the boiler heating surface are divided into different temperature zones, so that one or more wall temperature measuring points in each temperature zone are only affected by the changes in the corresponding cooling water, laying the foundation for steam temperature control to actively suppress wall temperature overheating.

[0064] The following is an example of the part of the boiler heating surface that is higher than the heating surface:

[0065] like Figure 3 As shown in the figure, the part higher than the heating surface is where the high-temperature superheater is located. Figure 3 As shown in the figure, a plurality of wall temperature measuring points are arranged at the lower part of the high temperature superheater, and a plurality of desuperheaters are connected to one end of the high temperature superheater, and the plurality of desuperheaters form a multi-channel desuperheating water system. Referring to the installation position of each wall temperature measuring point and the design parameters of the desuperheating water system, the plurality of wall temperature measuring points above the heating surface are divided into their respective areas to obtain a plurality of temperature areas (temperature areas A, B, C, D).

[0066] In this example, each temperature zone includes multiple wall temperature measuring points, and the multiple temperature zones correspond one-to-one to multiple desuperheaters of the desuperheating water system, that is, temperature zones A, B, C, and D correspond to desuperheaters A, B, C, and D, respectively, and temperature zones A, B, C, and D are only affected by changes in the desuperheating water in the corresponding desuperheater.

[0067] The embodiment of the present application divides the areas to which each wall temperature measuring point of the boiler heating surface belongs, which can provide support for the refined suppression of wall temperature over-temperature phenomenon for each cooling water line.

[0068] S102, obtaining the maximum actual wall temperature of a wall temperature measuring point in each temperature zone among the multiple temperature zones at the current moment.

[0069] As a possible implementation method, the maximum actual wall temperature of the wall temperature measuring points in each of the multiple temperature zones at the current moment is taken, including: obtaining multiple actual wall temperature values ​​of the multiple wall temperature measuring points in each of the temperature zones at the current moment; and taking the maximum of the multiple actual wall temperature values ​​as the maximum actual wall temperature of the temperature zone.

[0070] That is to say, the actual maximum wall temperature of multiple wall temperature measuring points in each temperature zone is compared and calculated, that is, the maximum wall temperature value obtained from the multiple wall temperature measuring points in each temperature zone is taken.

[0071] Optionally, for multiple wall temperature measuring points belonging to each temperature zone, a large comparator is used to compare and output the actual maximum wall temperature of the wall temperature measuring points in each temperature zone. That is, a multi-input comparator is used to compare and calculate the actual maximum wall temperature of the wall temperature measuring points in each temperature zone.

[0072] S103, predicting and obtaining the predicted maximum wall temperature of each temperature zone at the next moment based on the actual maximum wall temperature of each temperature zone and the corresponding road steam temperature variation characteristics.

[0073] In a specific embodiment of the present application, the maximum wall temperature of each temperature zone at a future moment is predicted in real time, that is, the predicted maximum wall temperature of each temperature zone at the next moment is obtained.

[0074] It should be noted that each desuperheater corresponds to one channel of cooling water and one channel of steam temperature. Taking the temperature zones A, B, C, and D in the above example as an example, the temperature zones A, B, C, and D correspond to the desuperheaters A, B, C, and D respectively; desuperheaters A, B, C, and D correspond to the steam temperature of channel A, the steam temperature of channel B, the steam temperature of channel C, and the steam temperature of channel D respectively; that is, the temperature zones A, B, C, and D correspond to the steam temperature of channel A, the steam temperature of channel B, the steam temperature of channel C, and the steam temperature of channel D respectively.

[0075] As a possible implementation method, the change rate of the steam temperature corresponding to each temperature zone is extracted through multi-level differentiation, and the change rate is superimposed on the actual maximum wall temperature of the corresponding temperature zone to obtain the predicted maximum wall temperature of each temperature zone.

[0076] Optionally, the rate of change of the steam temperature in the corresponding path of each temperature zone is extracted by multi-level differentiation; the rate of change of the steam temperature is multiplied by the prediction duration and then superimposed on the actual maximum wall temperature of the corresponding temperature zone to obtain the predicted maximum wall temperature of each temperature zone.

[0077] It can be understood that, since the change trend of steam temperature is ahead of the change trend of wall temperature, the change trend of steam temperature is obtained first, and then the change trend of wall temperature is predicted based on the change trend of steam temperature. Multi-level differential advance is used to extract the change trend of steam temperature in each temperature zone, and it is superimposed on the maximum wall temperature of the wall temperature measuring point at the current moment in the corresponding temperature zone, so as to realize the real-time prediction of the maximum wall temperature of each temperature zone.

[0078] It should be noted that the predicted duration is the duration between the current moment and the next moment. As an example, the predicted duration may be 3 minutes.

[0079] The following is an example of obtaining the predicted maximum wall temperature of temperature zone A at the next moment:

[0080] Temperature zone A corresponds to the steam temperature of circuit A (i.e. the steam temperature of cooling water circuit A), such as Figure 4 As shown in the figure, the change rate of the steam temperature of the steam temperature in the A line is extracted by multi-level differentiation. After the change rate of the steam temperature is multiplied by the prediction time, it is superimposed on the maximum wall temperature of the temperature area A to obtain the predicted maximum wall temperature of each temperature area at the next moment (i.e. Figure 3 The wall temperature prediction value in is used to realize the advance prediction of wall temperature.

[0081] Optionally, the unit of steam temperature rate is ℃ / s and the unit of prediction time is s.

[0082] S104, obtaining a wall temperature weighted value according to the predicted maximum wall temperature of each temperature zone and a preset weighted value; and actively suppressing wall temperature overheating in a coal-water synergistic manner based on the wall temperature weighted value.

[0083] Optionally, a method for obtaining a wall temperature weighted value according to the predicted maximum wall temperature corresponding to each temperature zone includes:

[0084] The predicted maximum wall temperature corresponding to each temperature zone is multiplied by the corresponding preset weighted value and then summed to obtain the wall temperature weighted value.

[0085] Furthermore, the predicted maximum values ​​of the wall temperatures corresponding to each temperature zone are compared to obtain a comparison result;

[0086] According to the comparison result, matching the predicted maximum wall temperature corresponding to each temperature zone with a corresponding preset weighted value;

[0087] The predicted maximum wall temperature corresponding to each temperature zone is multiplied by the corresponding preset weighted value and then summed to obtain a wall temperature weighted value.

[0088] Optionally, the minimum value among the predicted maximum wall temperatures of each temperature zone is eliminated, and then the predicted maximum wall temperatures of the remaining temperature zones are weighted to form a wall temperature weighted value suitable for the synergistic active suppression of wall temperature over-temperature by coal and water.

[0089] As an example, Figure 5 As shown, taking the preset weighted values ​​of 0.7 and 0.3 as an example, the minimum value among the predicted maximum wall temperatures of each temperature zone is first eliminated, and then the predicted maximum wall temperatures of the remaining temperature zones are weighted. Specifically, the maximum value among the predicted maximum wall temperatures of the remaining three temperature zones is determined by comparison, and after the maximum value is weighted by 0.7, the predicted maximum wall temperatures of the other two temperature zones are averaged and weighted by 0.3, finally forming a wall temperature weighted value suitable for active suppression of coal and water.

[0090] In the above example, the preset weighted value corresponding to the smallest of the predicted maximum wall temperatures corresponding to each temperature zone is 0, the preset weighted value corresponding to the largest of the predicted maximum wall temperatures corresponding to each temperature zone is 0.7, and the preset weighted values ​​corresponding to the actual maximum wall temperatures corresponding to the remaining two temperature zones are 0.15 respectively.

[0091] Optionally, a method for actively suppressing wall temperature overheating by coal-water synergy based on the wall temperature weighted value includes:

[0092] Determining whether the wall temperature weighted value and the wall temperature alarm value satisfy a preset relationship;

[0093] When the wall temperature weighted value and the wall temperature alarm value satisfy a preset relationship, a coal-water synergy is used to actively suppress wall temperature over-temperature.

[0094] Optionally, a method of actively suppressing wall temperature overheating by coal-water synergy includes:

[0095] The amount of coal and water added to the combustion system is corrected according to a preset function through the boiler control system.

[0096] Optionally, judging whether the wall temperature weighted value and the wall temperature alarm value satisfy a preset relationship includes:

[0097] Calculating the difference between the wall temperature weighted value and the wall temperature alarm value;

[0098] Determine whether the difference is greater than the wall temperature over-limit margin, and obtain a determination result;

[0099] According to the judgment result, it is judged whether the wall temperature weighted value and the wall temperature alarm value satisfy a preset relationship.

[0100] The specific embodiment of the present application, through logical configuration design, reduces coal and adds water in time when the wall temperature weighted value is close to overtemperature, and restores the original coal and water control when the wall temperature weighted value is adjusted back, thereby realizing coarse adjustment of active suppression of wall temperature overtemperature.

[0101] As an example, Figure 6 As shown, when the wall temperature weighted value is greater than the wall temperature alarm value by a certain margin (i.e., the wall temperature exceeds the limit margin), the RS trigger is set in time to select the output coal-water correction function F(X), that is, the output coal supply correction instruction and the water supply correction instruction to achieve coal reduction and water addition (for example, the coal-water ratio is 5 times) to correct the amount of coal and water added.

[0102] Where X is the deviation between the wall temperature weighted value and the wall temperature alarm value.

[0103] It can be understood that the RS trigger is a trigger in the boiler control system used to control whether to correct the amount of coal and water added.

[0104] Table 1: Parameter settings of F(X) in the function logic block

[0105]

[0106]

[0107] When the wall temperature weighted value recovers to a certain margin of the wall temperature alarm value and has a callback trend, the RS trigger is reset in time and the output is 0, that is, the original coal and water addition amounts are not corrected, and the coal and water corrections are restored to zero.

[0108] In this embodiment, the method for determining whether the wall temperature weighted value has a callback trend includes: extracting the change trend of the wall temperature weighted value by differentiation, and if the change trend is less than 0, it indicates that there is a callback trend.

[0109] It should be noted that the coal-water synergy method used here to actively suppress wall temperature overheating is a coarse adjustment. When it takes effect, the wall temperature of each temperature zone will be suppressed.

[0110] S105, based on the predicted maximum wall temperature of each temperature zone and the wall temperature alarm value, actively suppress the wall temperature from overheating by using a cooling water collaborative method.

[0111] The embodiment of the present application introduces the real-time predicted maximum wall temperature of each temperature zone into the cooling water control loop of the boiler. When the predicted maximum wall temperature of each temperature zone is close to the over-temperature limit, the cooling water valve corresponding to the cooling water system is opened in time to achieve fine adjustment of active suppression of over-temperature of the wall temperature in each temperature zone.

[0112] Optionally, based on the predicted maximum wall temperature and the wall temperature alarm value corresponding to each temperature zone, cooling water is used to actively suppress the wall temperature over-temperature phenomenon, including:

[0113] Calculate the difference between the predicted maximum wall temperature and the wall temperature alarm value corresponding to each temperature zone to obtain the wall temperature difference;

[0114] Calculate the difference between the actual steam temperature of the cooling water in each temperature zone and the corresponding steam temperature setting value to obtain the steam temperature difference;

[0115] The positive and negative parts of the steam temperature difference and the positive part of the wall temperature difference are respectively formed by limiting;

[0116] determining the greater of a positive portion of the steam temperature difference and a positive portion of the wall temperature difference;

[0117] Calculate the sum of the larger value and the negative value of the steam temperature difference to obtain a temperature deviation;

[0118] Based on the temperature deviation, the controller of the desuperheating water system generates the desuperheating valve opening of the desuperheating water in the corresponding path of each temperature zone;

[0119] The corresponding cooling valve is controlled according to the cooling valve opening, so as to actively suppress the wall temperature overheating in coordination with the cooling water.

[0120] The following is an example of temperature zone A (temperature zone A corresponds to the steam temperature of circuit A, i.e. the steam temperature of cooling water circuit A):

[0121] like Figure 7As shown, the actual value of the steam temperature in line A is subtracted from the set value of the steam temperature in line A to obtain the steam temperature difference; and the predicted maximum wall temperature in temperature area A is subtracted from the wall temperature alarm value to obtain the wall temperature difference; and then the steam temperature difference is formed into two parts greater than zero and less than zero respectively through limiting; because it is necessary to suppress the wall temperature over-temperature, for the part greater than zero, the larger of the steam temperature difference and the wall temperature difference is taken, and the deviation formed by the larger one and the part of the steam temperature difference less than zero is sent to the controller of the cooling water system to generate the cooling valve opening instruction of the cooling water in line A, and the cooling valve is opened according to the cooling valve opening instruction to realize the fine adjustment of the active suppression of the wall temperature over-temperature in each temperature area.

[0122] It should be noted that the steam temperature difference will not have a part greater than zero and a part less than zero. If the wall temperature is not considered, one of the parts greater than zero and less than zero is always zero, and the difference is exactly the sum. Since the wall temperature overheating problem is considered, only the part of the wall temperature difference greater than zero is concerned. At this time, the steam temperature may be under-temperatured, but the wall temperature overheating will also occur: the part greater than zero and the part less than zero will occur at the same time.

[0123] A method for actively suppressing overtemperature of a boiler wall temperature in an embodiment of the present application can realize the rough adjustment of active suppression of overtemperature of the wall temperature by actively suppressing overtemperature of the wall temperature through the synergy of coal and water, so that the wall temperature of each temperature zone is generally controlled within the adjustable range of the cooling water; the maximum value of the wall temperature of each temperature zone at a future moment is predicted in real time, so that the active suppression of overtemperature of the wall temperature can be adjusted in advance, and the overshoot of overtemperature of the wall temperature can be reduced, which is conducive to the stable operation of the wall temperature of the heating surface of the boiler; combined with the active suppression of overtemperature of the wall temperature by the cooling water, the fine adjustment of active suppression of overtemperature of the wall temperature in each temperature zone can be realized, so that the wall temperature of each temperature zone reaches its own optimal operating state; this scheme can effectively reduce the overtemperature phenomenon of the boiler wall temperature and ensure the safe and stable operation of each heating surface of the boiler. After considering the specification and practicing the invention disclosed here, those skilled in the art will easily think of other embodiments of the present application. The present application is intended to cover any modification, use or adaptive change of the present application, which follows the general principles of the present application and includes the common knowledge or customary technical means in the technical field not disclosed in the present application. The specification and the embodiments are only to be regarded as exemplary.

[0124] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for actively suppressing overtemperature of boiler wall temperature, characterized in that: include: According to the temperature influence of each cooling water channel on the multiple wall temperature measuring points of the boiler heating surface, the multiple wall temperature measuring points are divided into regions to obtain multiple temperature regions; Obtaining the maximum actual wall temperature of a wall temperature measuring point in each of the multiple temperature zones at the current moment; Based on the actual maximum wall temperature of each temperature zone and the change characteristics of the corresponding steam temperature, predict and obtain the predicted maximum wall temperature of each temperature zone at the next moment; Obtaining a wall temperature weighted value according to the predicted maximum wall temperature of each temperature zone and a preset weighted value; and actively suppressing wall temperature overheating in a coal-water synergistic manner based on the wall temperature weighted value; Based on the predicted maximum wall temperature and the wall temperature alarm value of each temperature zone, the over-temperature of the wall is actively suppressed by using the cooling water synergistic method; The predicting and obtaining the predicted maximum wall temperature of each temperature zone at the next moment based on the actual maximum wall temperature of each temperature zone and the change characteristics of the corresponding steam temperature, includes: Extracting the change rate of the steam temperature corresponding to each temperature zone through multi-level differentiation; The change rate of the steam temperature is multiplied by the prediction time and then added to the actual maximum wall temperature of the corresponding temperature zone to obtain the predicted maximum wall temperature of each temperature zone; The step of obtaining a wall temperature weighted value according to the predicted maximum wall temperature of each temperature zone and a preset weighted value comprises: The predicted maximum wall temperature of each temperature zone is multiplied by the corresponding preset weighted value and then summed to obtain a wall temperature weighted value; Based on the wall temperature weighted value, a coal-water synergy method is used to actively suppress wall temperature overheating, including: Determining whether the wall temperature weighted value and the wall temperature alarm value satisfy a first preset relationship; When the wall temperature weighted value and the wall temperature alarm value satisfy a first preset relationship, the amount of coal and water added to the combustion system is corrected by the boiler control system according to a preset function to actively suppress over-temperature of the wall temperature; The method of actively suppressing wall temperature over-temperature by using cooling water in coordination based on the predicted maximum wall temperature of each temperature zone and the wall temperature alarm value includes: When the predicted maximum wall temperature of each temperature zone and the wall temperature alarm value satisfy a second preset relationship, a cooling water collaborative method is used to actively suppress the wall temperature overtemperature; When the predicted maximum wall temperature in each temperature zone and the wall temperature alarm value satisfy a second preset relationship, actively suppressing the wall temperature overtemperature by using a cooling water collaborative method includes: Calculate the difference between the predicted maximum wall temperature of each temperature zone and the wall temperature alarm value to obtain the wall temperature difference; Calculate the difference between the actual steam temperature value of the desuperheating water path corresponding to each temperature zone and the corresponding steam temperature set value to obtain the steam temperature difference; The positive and negative parts of the steam temperature difference and the positive part of the wall temperature difference are respectively formed by limiting; determining the greater of a positive portion of the steam temperature difference and a positive portion of the wall temperature difference; Calculate the sum of the larger value and the negative value of the steam temperature difference to obtain a temperature deviation; Based on the temperature deviation, a controller of the desuperheating water system generates a desuperheating valve opening instruction for desuperheating water in the corresponding path of each temperature zone; The corresponding cooling valve is controlled according to the cooling valve opening instruction to actively suppress wall temperature overtemperature in coordination with cooling water.

2. The suppression method according to claim 1, characterized in that: According to the temperature influence of each cooling water on the multiple wall temperature measuring points of the boiler heating surface, the multiple wall temperature measuring points are divided into regions to obtain multiple temperature regions, including: Determine the temperature influence of each cooling water channel on the multiple wall temperature measuring points according to the installation positions of the multiple wall temperature measuring points; According to the temperature influence of each channel of cooling water on the multiple wall temperature measuring points, the multiple wall temperature measuring points are divided into regions to obtain multiple temperature regions.

3. The suppression method according to claim 1, characterized in that: The obtaining of the actual maximum value of the wall temperature of the wall temperature measuring point in each of the multiple temperature zones at the current moment comprises: Acquire multiple actual wall temperature values ​​of multiple wall temperature measuring points in each temperature zone at the current moment; The maximum value among the multiple actual wall temperature values ​​is taken as the maximum actual wall temperature of the temperature zone.

4. The suppression method according to claim 1, characterized in that: The step of multiplying the predicted maximum wall temperature of each temperature zone by the corresponding preset weighted value and then summing the results to obtain the wall temperature weighted value includes: Comparing the predicted maximum wall temperatures corresponding to the temperature zones to obtain a comparison result; According to the comparison result, matching the predicted maximum wall temperature of each temperature zone with a corresponding preset weighted value; The predicted maximum wall temperature of each temperature zone is multiplied by a matching preset weighted value and then summed to obtain a wall temperature weighted value.

5. The suppression method according to claim 1, characterized in that: The determining whether the wall temperature weighted value and the wall temperature alarm value satisfy a first preset relationship includes: Calculating the difference between the wall temperature weighted value and the wall temperature alarm value; Determine whether the difference is greater than the wall temperature over-limit margin, and obtain a determination result; According to the judgment result, it is judged whether the wall temperature weighted value and the wall temperature alarm value satisfy a first preset relationship.

6. The suppression method according to claim 1, characterized in that: After actively suppressing the wall temperature over-temperature by coal-water synergy based on the wall temperature weighted value, the method further includes: When the wall temperature weighted value and the wall temperature alarm value do not satisfy the first preset relationship, the boiler control system restores the original coal and water addition amounts of the combustion system.

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