A boiler soot blowing test and optimization system and method

Abstract

This invention discloses a boiler soot blowing testing and optimization system and method, comprising: during soot blowing, judging the wall temperature and fouling factor of the heated surface tubes within the effective space of the current sootblower; if within the safe boundary range, outputting a current soot blowing safety signal; after the safety module takes effect, testing each preset soot blowing method based on the arrangement of the sootblowers on the boiler heated surface, recording the test data of each test, and forming a soot blowing relationship database; obtaining the net soot blowing benefit by calculating the difference between the total benefit brought by the computer group soot blowing and the energy loss of soot blowing based on the soot blowing relationship database obtained during the test; the total benefit brought by the unit soot blowing includes the benefit brought by the reduction of turbine heat consumption and the increase of boiler heat load; and outputting an optimized soot blowing method based on the net soot blowing benefit. This invention can adaptively perform online testing and optimization of soot blowing strategies based on soot blowing tests, improving the operating economy and safety of generator boilers.

Description

Technical Field

[0001] This invention relates to the field of coal-fired power generation technology, specifically to a boiler soot blowing test and optimization system and method. Background Technology

[0002] Ash and slag buildup on the heating surfaces are common problems in power plant boilers during operation. Ash buildup reduces heat exchange efficiency, increases fuel consumption, and can lead to corrosion and wear of the heating surfaces, increasing pollutant emissions. It can even cause localized overheating of the heating surfaces, resulting in serious safety accidents such as tube rupture. The main causes of ash and slag buildup include changes in coal type and boiler operating conditions. Therefore, keeping the heating surfaces of power plant boilers clean is an important measure to ensure safe, economical, and environmentally friendly boiler operation. To solve these problems, the widely adopted method is to install soot blowing systems. Soot blowing systems mainly include steam soot blowing, gas pulse soot blowing, gas shock wave soot blowing, and sonic soot blowing. The working principle of these systems is to use different media (such as steam, gas, and sound waves) to clean the heating surfaces, thereby reducing ash and slag buildup.

[0003] However, existing sootblowing systems have some problems. For example, many sootblowers consume a lot of energy and media during operation, resulting in high operating costs and potentially causing erosion of the heated surfaces, affecting their safety. In addition, many power plants lack effective ash and dirt monitoring systems for heated surfaces, causing sootblowing strategies to often rely on the experience of operators rather than real-time ash and dirt data, which may lead to incomplete sootblowing or over-blowing.

[0004] Current technologies for monitoring ash and fouling on boiler heating surfaces mainly include mathematical model-based monitoring, acoustic temperature measurement, online monitoring parameter analysis, and support vector machine algorithms. While each technology has its own characteristics, they also share some common challenges. First, the high temperatures and harsh environment inside the boiler pose challenges to monitoring equipment, requiring specialized design and materials to ensure stability and lifespan. Second, the complex environment and equipment inside the boiler may interfere with monitoring signals, affecting accuracy. Third, the development, installation, and maintenance of advanced monitoring systems involve high costs, hindering technology adoption. Furthermore, some monitoring technologies are complex, requiring professional operation and maintenance, further increasing the technical threshold. Summary of the Invention

[0005] To address the aforementioned technical problems, the purpose of this application is to propose a boiler soot blowing test and optimization system and method. By comparing the status parameters of the soot blowing system of a coal-fired power generation unit with the effective soot blowing cost range in real time, the system can find the optimal economic operation mode of the soot blowing system while ensuring the safety of the unit. Furthermore, it can propose optimized soot blowing guidance methods based on the actual operating conditions of the unit, effectively guiding the soot blowing method on site.

[0006] The technical solution of the present invention is as follows.

[0007] On the one hand, a boiler soot blowing test and optimization system includes:

[0008] The soot blowing safety determination module is used to activate the corresponding soot blower for soot blowing when the contamination factor of each heated surface is higher than the start threshold under stable unit load conditions, and to stop soot blowing when the contamination factor of each heated surface is lower than the stop threshold. During the soot blowing process, the module judges the wall temperature and contamination factor of the heated surface within the effective space of the current soot blower. If they are within their respective safety limits, the module outputs the current soot blowing safety signal. The safety limit range of the heated surface wall temperature is based on the upper limit of the wall temperature and a preset threshold for the rate of decrease of the wall temperature. The safety limit range of the contamination factor is based on the start threshold, stop threshold, and preset threshold for the rate of decrease of the contamination factor. Each threshold is generated iteratively by the soot blowing safety determination module through online acquisition of data from multiple soot blowing processes of the unit's heated surfaces. The generation of these thresholds indicates that the soot blowing safety determination module is activated and effective.

[0009] The soot blowing efficiency test module is used to test each preset soot blowing method based on the arrangement of soot blowers on the boiler heating surface after the soot blowing safety judgment module is activated. The test data of each test is recorded to form a soot blowing relationship database. The soot blowing method includes single-variable and multi-variable tests based on the output adjustment of the soot blowing power source for each load condition branch divided according to the real-time power threshold of the coal-fired generator unit. The soot blowing relationship database includes a set of unit heat consumption parameters, a set of soot blowing energy consumption parameters, a set of enthalpy parameters of the working fluid of each heating surface of the boiler, a set of fouling factor parameters of each heating surface of the boiler, and a set of effective soot blowing time parameters under various soot blowing conditions of each heating surface of the boiler.

[0010] The effective soot blowing cost calculation module is used to obtain the net soot blowing benefit based on the difference between the total benefit brought by the computer group soot blowing and the energy loss of soot blowing, according to the soot blowing relationship database obtained during the test, after the soot blowing safety judgment module is activated and effective; the total benefit brought by the unit soot blowing includes the benefit brought by the reduction of turbine heat consumption and the increase of boiler heat load.

[0011] The soot blowing guidance module is used to output an optimized soot blowing method based on the net soot blowing revenue after the effective soot blowing cost calculation module has completed its iteration.

[0012] Preferably, the soot blowing safety determination module is further configured to: issue an alarm signal, stop the soot blowing efficiency test module and the soot blowing cost calculation module, activate the normal continuous soot blowing function, and mark the test and calculation results as invalid if the wall temperature or contamination factor of the heated surface in the effective space range of the current soot blower is not within the corresponding safety limit range.

[0013] Preferably, based on the safety range formed by the same contaminant initiation threshold and contaminant stop threshold, in each load condition branch, starting from the single-variable test stage, the output adjustment of the soot blowing power source is changed to obtain the effective soot blowing time for different output adjustment, thereby realizing the soot blowing test of a single soot blowing power source and the acquisition of the soot blowing relationship database; after completing all single-variable tests, the multi-variable test stage is entered, and the output adjustment of each soot blowing power source is changed when different soot blowing power sources are working simultaneously to conduct soot blowing tests, obtain the effective soot blowing time for different output adjustment, thereby realizing the soot blowing test and the acquisition of the soot blowing relationship database when two or more soot blowing power sources are working simultaneously.

[0014] Preferably, the effective soot blowing time is generated when the actual soot factor decreases to a level less than a preset threshold and is delayed by a preset time threshold.

[0015] Preferably, the different soot blowing power sources include two or more steam soot blowing methods that extract steam from different parts, or one steam method combined with other non-steam media for soot blowing.

[0016] Preferably, the enthalpy of the working fluid on each heating surface of the boiler is obtained in real time using the enthalpy calculation function block of the industrial control system based on the real-time pressure and temperature of the working fluid.

[0017] Preferably, the benefit from the reduction in turbine heat consumption is equal to the product of turbine heat consumption and effective soot blowing time; the benefit from the increase in boiler heat load is equal to the product of boiler heat load and effective soot blowing time.

[0018] Preferably, the energy loss from soot blowing is expressed as follows:

[0019] P D1 =Σ(Ds n ×h n ×t sn )+Σ(E m ×K m ×t sm )

[0020] Among them, P D1 Indicates energy loss during soot blowing; Ds n This represents the amount of steam consumed per unit time for soot blowing from different steam extraction sources; h n Indicates the enthalpy of soot blowing steam from different extraction steam sources; t sn Indicates the duration of soot blowing for different extraction steam sources; E m Indicates the energy consumption parameters of other media soot blowers; K m This represents the conversion factor for converting the energy consumption parameters of other media sootblowers to the energy unit kilojoules; t sm This indicates the duration of soot blowing by other media soot blowers; both n and m are greater than or equal to 1.

[0021] Preferably, the soot blowing guidance module is specifically used for:

[0022] The system assesses the net benefit of soot blowing. When the net benefit is greater than 0, it obtains the maximum value of the net benefit in each soot blowing test and outputs the optimized soot blowing method, prompting operators to select a suitable soot blowing power source and adjust the output of the soot blowing power source. When the net benefit is less than or equal to 0, it outputs a stop soot blowing signal and / or an alarm signal.

[0023] On the other hand, a boiler soot blowing test and optimization method includes:

[0024] Under stable unit load conditions, when the contamination factor of each heated surface is higher than the start threshold, the corresponding sootblower is activated for soot blowing. When the contamination factor of each heated surface is lower than the stop threshold, the sootblower stops blowing. During the soot blowing process, the wall temperature and contamination factor of the heated surface within the effective space of the current sootblower are judged. If they are within their respective safety limits, a current soot blowing safety signal is output. The safety limit range of the heated surface wall temperature is based on the upper limit of the wall temperature and a preset threshold for the rate of decrease of the wall temperature. The safety limit range of the contamination factor is based on the contamination factor start threshold, the contamination factor stop threshold, and the preset threshold for the rate of decrease of the contamination factor. Each threshold is generated iteratively by the soot blowing safety judgment module through online acquisition of data from multiple soot blowing processes of the unit's heated surfaces. The generation of these thresholds indicates that the soot blowing safety judgment module is activated and effective.

[0025] After the soot blowing safety judgment module is activated, the soot blowing methods preset based on the arrangement of soot blowers on the boiler heating surfaces are tested one by one, and the test data of each test is recorded to form a soot blowing relationship database. The soot blowing methods include single-variable and multi-variable tests for each load condition branch divided according to the real-time power threshold of the coal-fired power generation unit, based on the output adjustment of the soot blowing power source. The soot blowing relationship database includes the unit heat consumption parameter set, the soot blowing energy consumption parameter set, the enthalpy parameter set of the working fluid of each heating surface of the boiler, the fouling factor parameter set of each heating surface of the boiler, and the effective soot blowing time parameter set of each heating surface of the boiler under various soot blowing conditions.

[0026] After the soot blowing safety judgment module is activated, the net benefit of soot blowing is obtained based on the soot blowing relationship database obtained during the test and the difference between the total benefit brought by the computer group soot blowing and the energy loss of soot blowing. The total benefit brought by the unit soot blowing includes the benefit brought by the reduction of turbine heat consumption and the increase of boiler heat load.

[0027] After the effective soot blowing cost calculation module has been iterated, the optimized soot blowing method is output based on the net soot blowing revenue.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention is based on an industrial control system software calculation engine. It uses a sootblowing safety assessment module to determine the safety of sootblowing based on the fouling factors of each heating surface of a coal-fired power plant boiler, combined with a database of temperature measurement points on the heating surface tube walls and the correlation between the sootblower layout and the fouling factors. Once the safety module is activated, the sootblowing efficiency test module and the effective sootblowing cost calculation module are automatically activated. Using the basic fouling factors and wall temperatures after boiler cleaning as benchmark values, different steam parameters from the sootblower are superimposed to establish sootblowing test schemes under different load ranges. Then, using the set of unit heat consumption parameters, sootblowing energy consumption parameters, enthalpy parameters of the working fluid on each heating surface of the boiler, fouling factor parameters of each heating surface of the boiler, and effective sootblowing time parameters under various sootblowing conditions obtained during the test, the effective sootblowing cost is calculated. Based on the calculated sootblowing cost, the sootblowing guidance module outputs optimized sootblowing methods. This method requires less investment and yields quick results, not only helping to improve the operational economy and safety of power plant boilers and increase industrial production efficiency and economic benefits, but also meeting the strategic requirements of national sustainable development, thus possessing significant social and economic value.

[0030] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are listed below.

[0031] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a structural block diagram of the boiler soot blowing test and optimization system according to an embodiment of the present invention;

[0034] Figure 2 This is an overall flowchart of the boiler soot blowing test and optimization system according to an embodiment of the present invention;

[0035] Figure 3 This is a flowchart illustrating the soot blowing efficiency testing module according to an embodiment of the present invention;

[0036] Figure 4 This is a flowchart of a boiler soot blowing test and optimization method according to an embodiment of the invention. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the step identifiers S401, S402, S403, etc. are used only for convenience of description and do not indicate the execution order. The corresponding execution order can be adjusted.

[0040] See Figure 1 and Figure 2 As shown, the present invention discloses a boiler soot blowing test and optimization system, which includes the following modules.

[0041] The soot blowing safety determination module 101 is used to activate the corresponding soot blower for soot blowing when the contamination factor of each heated surface is higher than the start threshold under stable unit load conditions, and to stop soot blowing when the contamination factor of each heated surface is lower than the stop threshold. During the soot blowing process, the module judges the wall temperature and contamination factor of the heated surface within the effective space of the current soot blower. If they are within their respective safety limits, the module outputs the current soot blowing safety signal. The safety limit range of the heated surface wall temperature is based on the upper limit of the wall temperature and a preset threshold for the rate of decrease of the wall temperature. The safety limit range of the contamination factor is based on the start threshold, stop threshold, and preset threshold for the rate of decrease of the contamination factor. Each threshold is generated iteratively by the soot blowing safety determination module through online acquisition of data from multiple soot blowing processes of the heated surface of the unit. The generation of these thresholds indicates that the soot blowing safety determination module is activated and effective.

[0042] The soot blowing efficiency test module 102 is used to test each preset soot blowing method based on the arrangement of soot blowers on the boiler heating surface after the soot blowing safety judgment module is activated, and record the test data of each test to form a soot blowing relationship database. The soot blowing method includes single-variable and multi-variable tests based on the output adjustment of the soot blowing power source for each load condition branch divided according to the real-time power threshold of the coal-fired generator set. The soot blowing relationship database includes a set of unit heat consumption parameters, a set of soot blowing energy consumption parameters, a set of enthalpy parameters of the working fluid of each heating surface of the boiler, a set of fouling factor parameters of each heating surface of the boiler, and a set of effective soot blowing time parameters under various soot blowing conditions of each heating surface of the boiler.

[0043] The effective soot blowing cost calculation module 103 is used to obtain the net soot blowing benefit based on the difference between the total benefit brought by the computer group soot blowing and the energy loss of soot blowing, according to the soot blowing relationship database obtained during the test, after the soot blowing safety judgment module is activated and effective; the total benefit brought by the unit soot blowing includes the benefit brought by the reduction of turbine heat consumption and the increase of boiler heat load.

[0044] The soot blowing guidance module 104 is used to output the optimized soot blowing method based on the net soot blowing revenue after the effective soot blowing cost calculation module has completed its iteration.

[0045] Specifically, this invention is based on the industrial control system software calculation engine. According to the fouling factor of each heating surface of the coal-fired power generation unit boiler, combined with the correlation database of the heating surface tube wall temperature measuring points and sootblower layout, the sootblowing safety judgment module is used to make a sootblowing safety judgment. After the safety module is activated, the sootblowing efficiency test module and the effective sootblowing cost calculation module are automatically activated. The basic fouling factor and wall temperature after boiler cleaning are used as the benchmark value, and different steam parameters of the sootblower are superimposed to establish a sootblowing test scheme under different load ranges. Then, the effective sootblowing cost is calculated using the set of unit heat consumption parameters, sootblowing energy consumption parameters, working fluid enthalpy parameters of each heating surface of the boiler, fouling factor parameters of each heating surface of the boiler, and effective sootblowing time parameters under various sootblowing conditions of each heating surface of the boiler obtained during the test.

[0046] By comparing the status parameters of the soot blowing system of coal-fired power generating units with the effective soot blowing cost range in real time, the optimal economic operation mode of the soot blowing system can be found under the premise of ensuring the safety of the unit. Based on the actual operating conditions of the unit, optimized soot blowing guidance can be proposed to effectively guide the soot blowing method on site.

[0047] Furthermore, the soot blowing safety determination module 101, under stable unit load conditions, starts the corresponding soot blower for soot blowing when the contamination factor of each heated surface is higher than the start threshold, and stops soot blowing when the contamination factor of each heated surface is lower than the stop threshold. During the soot blowing process, when the wall temperature of the heated surface and the contamination factor in the effective space range of the current soot blower are within their respective safety limits, the module outputs the current soot blowing safety.

[0048] It should be noted that the contamination factor is generated based on the structural process parameters of each heating surface of the coal-fired power generation unit boiler, and can be implemented according to existing technology. This embodiment does not impose any restrictions.

[0049] The soot blowing safety signal is a two-factor cross-verification signal that measures the rate and trend of change of the contamination factor on the heated surface and the pipe wall temperature within a continuous time interval from the start to the end of soot blowing. Specifically, the soot blowing safety signal flips when the contamination factor / pipe wall temperature changes in opposite directions, the rate of decrease of the contamination factor is less than a preset threshold for the rate of decrease of the contamination factor, or the rate of decrease of the pipe wall temperature is less than a preset threshold for the rate of decrease of the contamination factor.

[0050] The effective range of a sootblower refers to the area that the sootblower can reach and effectively remove accumulated ash or slag. The effective range of a sootblower can be determined based on its arrangement.

[0051] The soot blowing safety determination module is also used to: establish a safety boundary based on the contaminant activation threshold, contaminant stop threshold, contaminant descent rate preset threshold, pipe wall temperature upper limit, and pipe wall temperature descent rate preset threshold; if the pipe wall temperature or contaminant in the effective space of the current soot blower is not within the corresponding safety boundary range, issue an alarm signal, stop the soot blowing efficiency test module and the soot blowing cost calculation module, activate the normal continuous soot blowing function, and mark the test and calculation results as invalid.

[0052] Furthermore, in combination Figure 3 The following is a detailed description of the soot blowing efficiency test module 102.

[0053] Based on the arrangement of sootblowers on the boiler's heating surface, a suitable sootblowing test strategy is selected, and different sootblowing variable parameters are set (variable parameters include the output adjustment of different sootblowing power sources, different sootblowing devices, sootblowing time, and different unit loads). Each parameter is tested individually to ensure coverage of all sootblowing methods. The different sootblowing power sources can be steam sootblowing from two different extraction points, or a combination of steam and other non-steam media. During testing, the real-time power threshold of the coal-fired generator unit is divided into several load condition branches. In each load condition branch, starting from the single-variable test stage, the output adjustment of the sootblowing power source is changed to obtain the effective sootblowing time length for different output adjustment amounts, achieving sootblowing testing and cost coefficient set for a single sootblowing power source. After completing all single-variable tests, the multi-variable test stage is entered. When different sootblowing power sources are operating simultaneously, the output adjustment of each sootblowing power source is changed to conduct sootblowing tests, obtaining the effective sootblowing time length for different output adjustment amounts, achieving sootblowing testing and cost coefficient set when two or more sootblowing power sources are operating simultaneously. The effective soot blowing time is generated when the actual contamination factor and the upper boundary deviation of the contamination factor are less than a preset threshold and are delayed by a preset time threshold.

[0054] During the above tests, process data was collected in real time through industrial control systems or other measurement and recording methods to form a soot blowing relationship database. This database includes a set of unit heat consumption parameters (including unit load, turbine steam flow rate, main steam pressure and temperature, boiler feedwater flow rate, boiler feedwater pressure and temperature, reheat steam flow rate, cold section reheat steam pressure and temperature, hot section reheat steam pressure and temperature, boiler makeup water flow rate, boiler makeup water pressure and temperature, etc.), a set of soot blowing energy consumption parameters (including soot blowing steam pressure, soot blowing steam temperature, soot blowing steam flow rate, soot blowing steam regulating valve position, soot blowing steam consumption, soot blowing steam pressure and temperature, energy consumption parameters of soot blowers using acoustic or other media, soot blowing time, etc.), a set of enthalpy parameters of the working medium for each heating surface of the boiler (working medium includes boiler main steam, boiler feedwater, reheat steam, soot blowing steam, desuperheating water, etc.), a set of fouling factor parameters for each heating surface of the boiler, and a set of effective soot blowing time parameters for each heating surface of the boiler under various soot blowing conditions.

[0055] The enthalpy of the working fluid on each heating surface of the boiler is obtained in real time based on the real-time pressure and temperature of the working fluid using the enthalpy calculation function block of the industrial control system (which may be DCS, SCADA, PLC, etc.).

[0056] The following will illustrate the testing process using steam soot blowing with two different extraction points and a combination of steam and sonic soot blowing as examples.

[0057] I. When using steam extraction from two different locations for soot blowing, the following soot blowing test unit can be used in the soot blowing efficiency test module.

[0058] Step 1: Under the current unit load conditions, open the first soot blowing source steam pressure regulating valve by a certain step value (and change the soot blowing steam pressure accordingly) to conduct a soot blowing test on the boiler heating surface.

[0059] The meaning of the current unit load condition is that there is no need to adjust the unit load specifically for the test. The test can be started based on the current unit load. Our tests are generally divided into several load segments, such as 30% to 50%, 50% to 70%, and 70% to 90%.

[0060] Step 2: Under the current unit load conditions, close the first soot blowing steam pressure regulating valve and open the second soot blowing steam pressure regulating valve in a certain step (correspondingly changing the soot blowing steam pressure) to blow soot onto the boiler heating surface.

[0061] Step 3: Two-way steam source mixing opening test.

[0062] (1) The first soot blowing source steam pressure regulating valve is opened to a step value and maintained, and the second soot blowing source steam pressure regulating valve is opened to a certain step value to blow soot onto the boiler heating surface.

[0063] (2) The first soot blowing source steam pressure regulating valve is opened to two step values ​​and kept open, and the second soot blowing source steam pressure regulating valve is opened to a certain step value to blow soot onto the boiler heating surface.

[0064] (3) Repeat steps (1) and (2) until the steam pressure regulating valve of the first soot blowing source is fully open.

[0065] (4) The second soot blowing source steam pressure regulating valve is opened to a step value and maintained, and the first soot blowing source steam pressure regulating valve is opened to a certain step value to blow soot onto the boiler heating surface.

[0066] (5) The second soot blowing source steam pressure regulating valve is opened to two step values ​​and maintained, and the first soot blowing source steam pressure regulating valve is opened to a certain step value to blow soot onto the boiler heating surface.

[0067] (6) Repeat steps (4) and (5) until the second soot blowing source steam pressure regulating valve is fully open.

[0068] Step 4: Adjust the load range of different units and repeat the tests in Step 1, Step 2 and Step 3 above.

[0069] When performing each step of the soot blowing test, if the deviation between the actual contamination factor and the upper boundary of the contamination factor is less than the preset threshold, the test is stopped after a delay of one preset threshold time.

[0070] II. When using a combination of steam and sonic soot blowing, the following soot blowing test unit can be used in the soot blowing efficiency test module.

[0071] Step 1: Under the current unit load conditions, open the soot blowing steam pressure regulating valve by a certain step value (and change the soot blowing steam pressure accordingly) to blow soot onto the boiler heating surface.

[0072] Step 2: Close the soot blowing steam pressure regulating valve and start the soot blowing to blow soot onto the boiler heating surface.

[0073] Step 3: Mixed soot blowing test.

[0074] (1) Open the soot blowing steam pressure regulating valve to a step value and maintain the opening, start the soot blowing to blow soot on the boiler heating surface.

[0075] (2) Open the soot blowing steam pressure regulating valve to two step values ​​and maintain the opening, then start the sonic soot blowing to blow soot onto the boiler heating surface.

[0076] (3) Repeat steps (1) and (2) until the soot blowing steam pressure regulating valve is fully open.

[0077] (4) Adjust the load segments of different units and repeat the steps (1), (2), and (3) above.

[0078] Similarly, when performing each step of the soot blowing test, if the deviation between the actual contamination factor and the upper boundary of the contamination factor is less than the preset threshold, the test is stopped after a delay of one preset threshold time.

[0079] Furthermore, the effective soot blowing cost calculation module 103 will be described in detail below.

[0080] Based on the soot blowing relationship database obtained during the aforementioned soot blowing efficiency test, including the set of unit heat consumption parameters, the set of soot blowing energy consumption parameters, the set of working fluid enthalpy parameters for each heating surface of the boiler, and the set of effective soot blowing duration parameters, the soot blowing cost is calculated.

[0081] According to the principles of thermal power plants, under a fixed power generation capacity, during soot blowing, the benefits from increased boiler heat load and reduced turbine heat consumption outweigh the energy losses from soot blowing. However, as the soot blowing time increases, the growth of soot blowing benefits slows down, and eventually the increase in energy consumption will exceed the benefits. By calculating soot blowing costs using a soot blowing relationship database obtained from soot blowing experiments, the maximum net benefit P from soot blowing can be found. max The profit from blowing dust in P max The range between 0 and 0 represents the economically feasible region for blowing away dust.

[0082] P net =P in -P out ;

[0083] P in =P Qb ;P Qb =Q b ×t s ;

[0084] Among them, P net Net gain from dust removal; P in Total revenue from soot blowing of the unit; P Qb The benefits resulting from reduced turbine heat consumption and increased boiler heat load; t s For effective soot blowing time.

[0085] P out =P D1

[0086] Among them, P out For the energy loss from soot blowing, P D1 This indicates the energy loss from soot blowing.

[0087] The feasible economic domain for dust removal is:

[0088] Benefits from increased boiler heat load + Benefits from reduced turbine heat consumption - Energy loss from soot blowing > 0.

[0089] Specifically, when there is a loss of soot blowing fluid, the turbine heat consumption Q0 and the boiler heat load Q b as follows:

[0090] Q0 = D0(h0-h fw )+D rh (h rh "-h rh ')-(ΣDs n (h) fw -h ma )-D w (h w -h ma )

[0091] Q b =Q0+(ΣDs) n (h) fw -h ma )+D w (h w -h ma )+Σ(Ds n (h n -h fw ))=D0(h0-h fw )+D rh (h rh "-h rh ')+Σ

[0092] (Ds n (h n -h fw ))

[0093] Where D0: turbine steam inlet flow rate, kg / h; h0: main steam enthalpy, kJ / kg; h fw Enthalpy of main feedwater in boiler, kJ / kg; D rh Reheat steam volume, kg / h; h rh ":Enthalpy of reheated hot section steam, kJ / kg; h" rh ': Enthalpy of reheat cold section steam, kJ / kg; Ds n Steam consumption for soot blowing using different steam extraction sources, kg / h; h n Enthalpy of sootblowing steam from different extraction steam sources, kJ / kg; D w Cooling water volume, kg / h; h w Enthalpy of desuperheated water, kJ / kg; h ma : Enthalpy of water replenishment, kJ / kg.

[0094] The energy loss from soot blowing is expressed as follows:

[0095] P D1 =Σ(Ds n ×h n ×t sn )+Σ(E m ×K m ×t sm )

[0096] Among them, P D1 Indicates energy loss from soot blowing; t sn Indicates the duration of soot blowing for different extraction steam sources; E m Indicates the energy consumption parameters of other media soot blowers; K m This represents the conversion factor for converting the energy consumption parameters of other media sootblowers to the energy unit kilojoules; t sm This indicates the duration of soot blowing by other media soot blowers; both m and n are greater than or equal to 1.

[0097] Furthermore, the soot blowing guidance module 104 compares in real time whether the cost of the soot blowing system of the coal-fired power generation unit is within the effective soot blowing cost range, finds the optimal economic operation mode of the soot blowing system, and can propose optimized soot blowing guidance methods based on the actual operating conditions of the unit, effectively guiding the soot blowing method on site.

[0098] Specifically, when the cost of soot blowing (net revenue from soot blowing) is close to or even less than 0, it indicates that the total revenue from soot blowing is less than the energy loss from soot blowing. An alarm will be issued to remind the operators to stop soot blowing and check whether there are leaks or other losses in the soot blowing system.

[0099] In different load ranges, operators are advised to select a suitable soot blowing source and a suitable soot blowing steam source opening for the heated surfaces to achieve greater benefits. That is, the third step of the aforementioned soot blowing test unit is to test and determine which soot blowing source is more suitable for different load ranges, that is, the soot blowing source that yields greater soot blowing benefits in different load ranges.

[0100] See Figure 4 As shown, this embodiment also discloses a boiler soot blowing test and optimization method, including:

[0101] S401, under stable unit load conditions, when the contamination factor of each heated surface is higher than the start threshold, the corresponding sootblower is activated for soot blowing; when the contamination factor of each heated surface is lower than the stop threshold, the corresponding sootblower stops blowing. During the soot blowing process, the wall temperature and contamination factor of the heated surface within the effective space of the current sootblower are judged. If they are within their respective safety limits, a current soot blowing safety signal is output. The safety limit range of the heated surface wall temperature is based on the upper limit of the wall temperature and a preset threshold for the rate of decrease of the wall temperature. The safety limit range of the contamination factor is based on the contamination factor start threshold, the contamination factor stop threshold, and the contamination factor decrease rate preset threshold. Each threshold is generated iteratively by the soot blowing safety judgment module through online acquisition of multiple soot blowing process data of the heated surface of the unit. The generation of these thresholds indicates that the soot blowing safety judgment module is activated and effective.

[0102] S402, after the soot blowing safety judgment module is activated, the soot blowing methods preset based on the arrangement of soot blowers on the boiler heating surfaces are tested one by one, and the test data of each test is recorded to form a soot blowing relationship database. The soot blowing methods include single-variable and multi-variable tests based on the output adjustment of the soot blowing power source for each load condition branch divided according to the real-time power threshold of the coal-fired power generation unit. The soot blowing relationship database includes the unit heat consumption parameter set, the soot blowing energy consumption parameter set, the enthalpy parameter set of the working fluid of each heating surface of the boiler, the fouling factor parameter set of each heating surface of the boiler, and the effective soot blowing time parameter set of each heating surface of the boiler under various soot blowing conditions.

[0103] S403, after the soot blowing safety judgment module is activated, the net benefit of soot blowing is obtained based on the soot blowing relationship database obtained during the test and the difference between the total benefit brought by the computer group soot blowing and the energy loss of soot blowing; the total benefit brought by the unit soot blowing includes the benefit brought by the reduction of turbine heat consumption and the increase of boiler heat load.

[0104] S404: After the effective soot blowing cost calculation module has completed its iteration, the optimized soot blowing method is output based on the net soot blowing revenue.

[0105] The specific implementation of a boiler soot blowing test and optimization method and the same boiler soot blowing test and optimization system will not be described again in this embodiment.

[0106] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A boiler soot blowing test and optimization system, characterized in that, include: The soot blowing safety judgment module is used to start the corresponding soot blower for soot blowing when the contamination factor of each heated surface is higher than the start threshold under stable unit load conditions, and to stop soot blowing when the contamination factor of each heated surface is lower than the stop threshold. During the soot blowing process, the heating surface tube wall temperature and contamination factor in the effective space range of the current soot blower are judged. If they are within their respective safety limits, the current soot blowing safety signal is output. The safe boundary range of the heating surface tube wall temperature is based on the upper limit of the tube wall temperature and the preset threshold of the tube wall temperature drop rate; the safe boundary range of the contamination factor is based on the contamination factor start threshold, the contamination factor stop threshold and the preset threshold of the contamination factor drop rate. Each threshold is generated iteratively by the online acquisition of multiple soot blowing process data of the heating surface of the unit by the soot blowing safety judgment module. The generation marks the activation and effectiveness of the soot blowing safety judgment module. The soot blowing efficiency test module is used to test each preset soot blowing method based on the arrangement of soot blowers on the boiler heating surface after the soot blowing safety judgment module is activated. The test data of each test is recorded to form a soot blowing relationship database. The soot blowing method includes single-variable and multi-variable tests based on the output adjustment of the soot blowing power source for each load condition branch divided according to the real-time power threshold of the coal-fired generator unit. The soot blowing relationship database includes a set of unit heat consumption parameters, a set of soot blowing energy consumption parameters, a set of enthalpy parameters of the working fluid of each heating surface of the boiler, a set of fouling factor parameters of each heating surface of the boiler, and a set of effective soot blowing time parameters under various soot blowing conditions of each heating surface of the boiler. The effective soot blowing cost calculation module is used to obtain the net soot blowing benefit based on the difference between the total benefit brought by the computer group soot blowing and the energy loss of soot blowing, according to the soot blowing relationship database obtained during the test, after the soot blowing safety judgment module is activated and effective; the total benefit brought by the unit soot blowing includes the benefit brought by the reduction of turbine heat consumption and the increase of boiler heat load. The soot blowing guidance module is used to output the optimized soot blowing method based on the net soot blowing revenue after the effective soot blowing cost calculation module has completed its iteration. Based on the safety range formed by the same contaminant start threshold and contaminant stop threshold, in each load condition branch, starting from the single-variable test stage, the output adjustment of the soot blowing power source is changed to obtain the effective soot blowing time for different output adjustment, realizing the soot blowing test of a single soot blowing power source and the acquisition of the soot blowing relationship database; after completing all single-variable tests, the multi-variable test stage is entered, and the output adjustment of each soot blowing power source is changed when different soot blowing power sources are working simultaneously to conduct soot blowing tests and obtain the effective soot blowing time for different output adjustment, realizing the soot blowing test and the acquisition of the soot blowing relationship database when two or more soot blowing power sources are working simultaneously; The benefit from the reduction in turbine heat consumption is equal to the product of turbine heat consumption and effective soot blowing time; the benefit from the increase in boiler heat load is equal to the product of boiler heat load and effective soot blowing time. The energy loss from soot blowing is expressed as follows: P D1 =Σ(Ds n ×h n ×t sn )+Σ(E m ×K m ×t sm ) Among them, P D1 Indicates energy loss during soot blowing; Ds n This represents the amount of steam consumed per unit time for soot blowing from different steam extraction sources; h n Indicates the enthalpy of soot blowing steam from different extraction steam sources; t sn Indicates the duration of soot blowing for different extraction steam sources; E m Indicates the energy consumption parameters of other media soot blowers; K m This represents the conversion factor for converting the energy consumption parameters of other media sootblowers to the energy unit kilojoules; t sm This indicates the duration of soot blowing by other media soot blowers; both n and m are greater than or equal to 1.

2. The boiler soot blowing test and optimization system according to claim 1, characterized in that, The soot blowing safety determination module is also used to: issue an alarm signal, stop the soot blowing efficiency test module and the soot blowing cost calculation module, activate the normal continuous soot blowing function, and mark the test and calculation results as invalid if the wall temperature or contamination factor of the heated surface in the effective space range of the current soot blower is not within the corresponding safety boundary range.

3. The boiler soot blowing test and optimization system according to claim 1, characterized in that, The effective soot blowing time is generated when the actual soot factor decreases to a level less than the soot factor stopping threshold and is delayed by a preset time threshold.

4. The boiler soot blowing test and optimization system according to claim 1, characterized in that, The different soot blowing power sources include two or more steam soot blowing methods that extract steam from different parts, or one type of steam plus other non-steam media for soot blowing.

5. The boiler soot blowing test and optimization system according to claim 1, characterized in that, The enthalpy of the working fluid on each heating surface of the boiler is obtained in real time using the enthalpy calculation function block of the industrial control system based on the real-time pressure and temperature of the working fluid.

6. The boiler soot blowing test and optimization system according to claim 1, characterized in that, The soot blowing guidance module is specifically used for: The system assesses the net benefit of soot blowing. When the net benefit is greater than 0, it obtains the maximum value of the net benefit in each soot blowing test and outputs the optimized soot blowing method, prompting operators to select a suitable soot blowing power source and adjust the output of the soot blowing power source. When the net benefit is less than or equal to 0, it outputs a stop soot blowing signal and / or an alarm signal.

7. A method for testing and optimizing boiler soot blowing, characterized in that, Based on any one of the claims 1 to 6, comprising: Under stable unit load conditions, when the contamination factor of each heated surface is higher than the start threshold, the corresponding sootblower is activated for soot blowing. When the contamination factor of each heated surface is lower than the stop threshold, the sootblower stops blowing. During the soot blowing process, the wall temperature and contamination factor of the heated surface within the effective space of the current sootblower are judged. If they are within their respective safety limits, a current soot blowing safety signal is output. The safety limit range of the heated surface wall temperature is based on the upper limit of the wall temperature and a preset threshold for the rate of decrease of the wall temperature. The safety limit range of the contamination factor is based on the contamination factor start threshold, the contamination factor stop threshold, and the preset threshold for the rate of decrease of the contamination factor. Each threshold is generated iteratively by the soot blowing safety judgment module through online acquisition of data from multiple soot blowing processes of the unit's heated surfaces. The generation of these thresholds indicates that the soot blowing safety judgment module is activated and effective. After the soot blowing safety judgment module is activated, the soot blowing methods preset based on the arrangement of soot blowers on the boiler heating surfaces are tested one by one, and the test data of each test is recorded to form a soot blowing relationship database. The soot blowing methods include single-variable and multi-variable tests for each load condition branch divided according to the real-time power threshold of the coal-fired power generation unit, based on the output adjustment of the soot blowing power source. The soot blowing relationship database includes the unit heat consumption parameter set, the soot blowing energy consumption parameter set, the enthalpy parameter set of the working fluid of each heating surface of the boiler, the fouling factor parameter set of each heating surface of the boiler, and the effective soot blowing time parameter set of each heating surface of the boiler under various soot blowing conditions. After the soot blowing safety judgment module is activated, the net benefit of soot blowing is obtained based on the soot blowing relationship database obtained during the test and the difference between the total benefit brought by the computer group soot blowing and the energy loss of soot blowing. The total benefit brought by the unit soot blowing includes the benefit brought by the reduction of turbine heat consumption and the increase of boiler heat load. After the effective soot blowing cost calculation module has been iterated, the optimized soot blowing method is output based on the net soot blowing revenue.

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