Boiler soot blowing test and optimization system and method

Abstract

The invention discloses a boiler soot blowing test and optimization system and method, and the method comprises the steps: judging a heating surface pipe wall temperature and a contamination factor in an effective space range of a current soot blower in a soot blowing process, and outputting a current soot blowing safety signal if the heating surface pipe wall temperature and the contamination factor are in a safe definite range; after the safety module takes effect, soot blowing modes preset based on the arrangement condition of soot blowers on the heating surface of the boiler are tested one by one, test data of each test are recorded, and a soot blowing relation database is formed; according to the soot blowing relation database obtained in the test process, the difference value between the total income brought by soot blowing of the unit and the soot blowing energy consumption loss is calculated, and the soot blowing net income is obtained; the total benefit brought by soot blowing of the unit comprises the benefit brought by heat consumption reduction of a steam turbine and heat load increase of a boiler; and outputting an optimized soot blowing mode according to the soot blowing net income. According to the method, online test and optimization of the soot blowing strategy can be adaptively carried out according to the soot blowing test, and the operation economy and safety of the generator set boiler are improved.

Description

Technical Field

[0001] The invention relates to the technical field of coal-fired power generation, and in particular to a boiler soot blowing test and optimization system and method. Background Art

[0002] During the operation of power station boilers, dust and slagging on the heating surface are common problems. Dust on the heating surface of the boiler will lead to a decrease in heat exchange efficiency, increase fuel consumption, corrosion and wear of the heating surface, increase pollutant emissions, and may even cause local overheating of the heating surface, leading to serious safety accidents such as pipe bursts. The main causes of dust accumulation and slagging include changes in coal types and boiler operating conditions. Therefore, keeping the heating surface of power station boilers clean is an important measure to ensure safe, economical and environmentally friendly operation of the boiler. In order to solve these problems, the widely used method is to install a soot blowing system. The soot blowing system mainly includes 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, sound waves, etc.) to clean the heating surface to reduce dust accumulation and slagging.

[0003] However, there are some problems with the existing sootblowing systems. For example, many sootblowers consume a lot of energy and medium during operation, resulting in high operating costs, and may cause erosion of the heating surface, affecting its safety. In addition, many power plants lack an effective heating surface soot contamination monitoring system, resulting in the formulation of sootblowing strategies often relying on the experience of operators rather than real-time soot contamination data, which may cause incomplete sootblowing or over-blowing.

[0004] The current boiler heating surface ash fouling monitoring technology mainly includes monitoring based on mathematical models, acoustic temperature measurement technology, online monitoring parameter analysis, and support vector machine algorithms. These technologies have their own characteristics, but there are also some common problems. First, the high temperature and harsh environment inside the boiler pose challenges to the monitoring equipment, requiring special design and materials to ensure the stability and life of the equipment. Second, the complex environment and equipment inside the boiler may interfere with the monitoring signal and affect the accuracy of the monitoring. Third, the research and development, installation and maintenance of advanced monitoring systems involve high costs, which has become an obstacle to the promotion of technology. In addition, some monitoring technologies may be more complex and require professional personnel to operate and maintain, which increases the technical threshold. Summary of the invention

[0005] In response to the technical problems mentioned above, the purpose of the embodiments of the present application is to propose a boiler sootblowing test and optimization system and method, which can find the best economic operation mode of the sootblowing system under the premise of ensuring the safety of the unit by comparing the state parameters of the sootblowing system of the coal-fired power generation unit with the effective sootblowing cost range in real time, and can propose an optimized sootblowing guidance method according to the actual operating conditions of the unit to effectively guide the on-site sootblowing method.

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

[0007] In one aspect, a boiler sootblowing testing and optimization system comprises:

[0008] A sootblowing safety determination module is used to start the corresponding sootblower for sootblowing when the contamination factor of each heating surface is higher than the start threshold under the condition of stable unit load, and stop the sootblowing of the corresponding sootblower when the contamination factor of each heating surface is lower than the stop threshold. During the sootblowing process, the tube wall temperature and contamination factor of the heating surface in the effective space range of the current sootblower are judged, and if they are within their respective safety limit ranges, a current sootblowing safety signal is output; the safety limit 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 safety limit 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, and each threshold is iteratively generated by the sootblowing safety determination module online collecting multiple sootblowing process data of the unit heating surface, and the generation indicates that the sootblowing safety determination module is activated and effective;

[0009] A sootblowing efficiency test module is used to test the sootblowing modes preset based on the arrangement of the sootblower on the heating surface of the boiler one by one after the sootblowing safety determination module is activated and becomes effective, record the test data of each test, and form a sootblowing relationship database; the sootblowing mode includes single variable test and multivariate test based on the output adjustment amount of the sootblowing power source for each load condition branch divided according to the real-time coal-fired power generation unit electric power threshold; the sootblowing relationship database includes a unit heat consumption parameter set, a sootblowing energy consumption parameter set, a boiler heating surface working medium enthalpy parameter set, a boiler heating surface contamination factor parameter set, and a boiler heating surface effective sootblowing time parameter set under various sootblowing conditions for each heating surface of the boiler;

[0010] The effective sootblowing cost calculation module is used to calculate the difference between the total benefit brought by the sootblowing of the unit and the energy loss of sootblowing according to the sootblowing relationship database obtained during the test process after the sootblowing safety judgment module is activated and becomes effective, so as to obtain the net benefit of sootblowing; the total benefit brought by the sootblowing of the unit includes the benefit brought by the reduction of the heat consumption of the steam turbine and the increase of the heat load of the boiler;

[0011] The sootblowing guidance module is used to output the optimized sootblowing method according to the net sootblowing benefit after the iteration of the effective sootblowing cost calculation module is completed.

[0012] Preferably, the sootblowing safety determination module is also used to: if the heating surface tube wall temperature or contamination factor of the current sootblower effective space range is not within the corresponding safety limit range, an alarm signal is issued, the sootblowing efficiency test module and the sootblowing cost calculation module are terminated, the normal continuous sootblowing function is activated, and the test and calculation results are marked as invalid.

[0013] Preferably, based on the safety interval formed by the start threshold value and the stop threshold value of the same contamination factor, in each load condition branch, starting from the single-variable test link, the output adjustment amount of the sootblowing power source is changed to obtain the effective sootblowing time of different output adjustment amounts, thereby realizing the sootblowing test of a single sootblowing power source and the acquisition of the sootblowing relationship database; after completing all single-variable tests, the multi-variable test link is entered, and the output adjustment amount of each sootblowing power source is changed when different sootblowing power sources are working at the same time, and a sootblowing test is performed to obtain the effective sootblowing time of different output adjustment amounts, thereby realizing the sootblowing test and the acquisition of the sootblowing relationship database when two or more sootblowing power sources are working at the same time.

[0014] Preferably, the effective sootblowing time is generated when the actual contamination factor decreases to a value less than a preset threshold value from the contamination factor stop threshold value and is delayed by a preset time threshold value.

[0015] Preferably, the different sootblowing power sources include two or more steam sootblowing with steam extracted from different locations or one type of steam plus other non-steam media sootblowing.

[0016] Preferably, the enthalpy of the working fluid at each heating surface of the boiler is obtained in real time by applying the enthalpy calculation function block of the industrial control system according to the real-time pressure and temperature of the working fluid.

[0017] Preferably, the benefit brought by the reduction in the heat consumption of the steam turbine is equal to the product of the heat consumption of the steam turbine and the effective sootblowing time; the benefit brought by the increase in the thermal load of the boiler is equal to the product of the thermal load of the boiler and the effective sootblowing time.

[0018] Preferably, the soot blowing energy loss 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 the soot blowing energy loss; Ds n Indicates the amount of steam consumed by soot blowing from different extraction steam sources per unit time; h n Indicates the enthalpy value of sootblowing steam from different extraction steam sources; t sn Indicates the duration of soot blowing with different extraction steam sources; E m Indicates the energy consumption parameters of other medium soot blowers; K m Indicates the conversion coefficient of other medium sootblower energy consumption parameters into energy unit kilojoule; t sm Indicates the duration of soot blowing by other medium soot blowers; n and m are both greater than or equal to 1.

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

[0022] The net sootblowing benefit is judged. When the net sootblowing benefit is greater than 0, the maximum value of the net sootblowing benefit in each sootblowing test is obtained, and the optimized sootblowing method is output to prompt the operating personnel to select a suitable sootblowing power source and the sootblowing power source output adjustment amount; when the net sootblowing benefit is less than or equal to 0, a stop sootblowing signal and / or an alarm signal is output.

[0023] In another aspect, a boiler sootblowing testing and optimization method includes:

[0024] Under the condition of stable unit load, when the contamination factor of each heating surface is higher than the start threshold, the corresponding sootblower is started for sootblowing; when the contamination factor of each heating surface is lower than the stop threshold, the corresponding sootblower stops sootblowing; during the sootblowing process, the tube wall temperature and contamination factor of the heating surface in the effective space range of the current sootblower are judged; if they are within their respective safety limits, the current sootblowing safety signal is output; the safety limit 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 safety limit 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, and each threshold is iteratively generated by the sootblowing safety judgment module online collecting multiple sootblowing process data of the unit heating surface, and the generation indicates that the sootblowing safety judgment module is activated and effective;

[0025] After the sootblowing safety determination module is activated and becomes effective, the sootblowing modes preset based on the arrangement of the sootblower on the boiler heating surface are tested one by one, and the test data of each test is recorded to form a sootblowing relationship database; the sootblowing mode includes single variable test and multivariable test based on the output adjustment amount of the sootblowing power source for each load condition branch divided according to the real-time coal-fired power generation unit electric power threshold; the sootblowing relationship database includes the unit heat consumption parameter set, the sootblowing energy consumption parameter set, the boiler heating surface working medium enthalpy parameter set, the boiler heating surface contamination factor parameter set and the effective sootblowing time parameter set under various sootblowing conditions for each heating surface of the boiler;

[0026] After the sootblowing safety determination module is activated and becomes effective, the difference between the total benefit brought by the sootblowing of the computer group and the energy loss of sootblowing is calculated according to the sootblowing relationship database obtained during the test process to obtain the net benefit of sootblowing; the total benefit brought by the sootblowing of the unit includes the benefits brought by the reduction of the heat consumption of the steam turbine and the increase of the heat load of the boiler;

[0027] After the iteration of the effective sootblowing cost calculation module is completed, the optimized sootblowing method is output according to the net sootblowing benefit.

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

[0029] The present invention is based on an industrial control system software calculation engine, and according to the contamination factor of each heating surface of the boiler of a coal-fired power generation unit, combined with the heating surface tube wall temperature measuring points and the sootblower arrangement association library, a sootblowing safety judgment module is used to perform sootblowing safety judgment; after the safety module takes effect, a sootblowing efficiency test module and an effective sootblowing cost calculation module are automatically activated, and the basic contamination factor and wall temperature after the boiler is cleaned are used as reference values, different steam parameters of the sootblower are superimposed, and a sootblowing test plan is established under different load intervals, and then the unit heat consumption parameter set, sootblowing energy consumption parameter set, boiler heating surface working medium enthalpy parameter set, boiler heating surface contamination factor parameter set and effective sootblowing time parameter set under various sootblowing conditions of each heating surface of the boiler obtained during the test are used to calculate the effective sootblowing cost; according to the calculated sootblowing cost, a sootblowing guidance module is used to output an optimized sootblowing method, which has low investment and quick results, not only helps to improve the operation economy and safety of power station boilers, improve industrial production efficiency and economic benefits, but also meets the strategic requirements of national sustainable development, and has important social and economic value.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention so that it can be implemented in accordance with the contents of the specification, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below.

[0031] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A structural block diagram of a boiler sootblowing test and optimization system according to an embodiment of the present invention;

[0034] Figure 2 It is an overall flow chart of the boiler sootblowing test and optimization system according to an embodiment of the present invention;

[0035] Figure 3 It is a schematic diagram of the flow of the soot blowing efficiency test module according to an embodiment of the present invention;

[0036] Figure 4 Flow chart of a boiler sootblowing testing and optimization method according to an embodiment of the invention. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "comprises", "includes" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, step identifiers S401, S402, S403, etc. are only used for convenient expression and do not represent the execution order, and the corresponding execution order can be adjusted.

[0040] See also Figure 1 and Figure 2 As shown, the present invention discloses a boiler sootblowing test and optimization system, comprising the following modules.

[0041] The sootblowing safety judgment module 101 is used to start the corresponding sootblower for sootblowing when the contamination factor of each heating surface is higher than the starting threshold value under the condition of stable unit load, and stop the sootblowing of the corresponding sootblower when the contamination factor of each heating surface is lower than the stopping threshold value. During the sootblowing process, the tube wall temperature and contamination factor of the heating surface in the effective space range of the current sootblower are judged, and if they are within their respective safety limit ranges, the current sootblowing safety signal is output; the safety limit range of the heating surface tube wall temperature is based on the upper limit of the tube wall temperature and the preset threshold value of the tube wall temperature drop rate; the safety limit range of the contamination factor is based on the contamination factor starting threshold value, the contamination factor stopping threshold value and the preset threshold value of the contamination factor drop rate, and each threshold value is iteratively generated by the sootblowing safety judgment module online collecting multiple sootblowing process data of the unit heating surface, and the generation indicates that the sootblowing safety judgment module is activated and effective;

[0042] The sootblowing efficiency test module 102 is used to test the sootblowing modes preset based on the arrangement of the sootblower on the boiler heating surface one by one after the sootblowing safety determination module is activated and becomes effective, record the test data of each test, and form a sootblowing relationship database; the sootblowing mode includes performing single variable tests and multivariable tests based on the output adjustment amount of the sootblowing power source for each load condition branch divided according to the real-time coal-fired power generation unit electric power threshold; the sootblowing relationship database includes a unit heat consumption parameter set, a sootblowing energy consumption parameter set, a boiler heating surface working medium enthalpy parameter set, a boiler heating surface contamination factor parameter set, and a boiler heating surface effective sootblowing time parameter set under various sootblowing conditions for each heating surface of the boiler;

[0043] The effective sootblowing cost calculation module 103 is used to calculate the difference between the total benefit brought by the sootblowing of the unit and the energy loss of sootblowing according to the sootblowing relationship database obtained during the test process after the sootblowing safety determination module is activated and becomes effective, so as to obtain the net benefit of sootblowing; the total benefit brought by the sootblowing of the unit includes the benefit brought by the reduction of the heat consumption of the steam turbine and the increase of the heat load of the boiler;

[0044] The sootblowing guidance module 104 is used to output an optimized sootblowing method according to the sootblowing net benefit after the effective sootblowing cost calculation module is iterated.

[0045] Specifically, the present invention is based on an industrial control system software computing engine, and according to the contamination factor of each heating surface of the boiler of a coal-fired power generation unit, combined with the heating surface tube wall temperature measuring points and the sootblower arrangement association library, a sootblowing safety judgment module is used to perform sootblowing safety judgment; after the safety module takes effect, the sootblowing efficiency test module and the effective sootblowing cost calculation module are automatically activated, and the basic contamination factor and wall temperature after boiler pollution control are used as reference values, and different steam parameters of the sootblower are superimposed, and a sootblowing test plan is established under different load ranges, and then the effective sootblowing cost is calculated using the unit heat consumption parameter set, sootblowing energy consumption parameter set, boiler heating surface working fluid enthalpy parameter set, boiler heating surface contamination factor parameter set, and effective sootblowing time parameter set under various sootblowing conditions of each heating surface of the boiler obtained during the test.

[0046] By comparing the state parameters of the sootblowing system of coal-fired power generation units with the effective sootblowing cost range in real time, the optimal economic operation mode of the sootblowing system is found while ensuring the safety of the unit. In addition, the optimized sootblowing guidance method can be proposed according to the actual operating conditions of the unit to effectively guide the sootblowing method on site.

[0047] Furthermore, the sootblowing safety judgment module 101 starts the corresponding sootblower for sootblowing when the contamination factor of each heating surface is higher than the start threshold when the unit load is stable, and stops sootblowing by the corresponding sootblower when the contamination factor of each heating surface is lower than the stop threshold. During the sootblowing process, when the heating surface tube wall temperature and the contamination factor of the current sootblower in the effective space range of the sootblower are within their respective safety limits, the current sootblowing safety is output.

[0048] It should be noted that the contamination factor is generated according to the structural process parameters of each heating surface of the boiler of the coal-fired power generation unit, which can be specifically implemented according to the existing technology and is not limited in this embodiment.

[0049] The sootblowing safety signal is a double-factor cross-validation signal of the numerical change rate and trend of the heating surface contamination factor and the tube wall temperature in a continuous time interval from the start to the end of sootblowing, that is, when the contamination factor / tube wall temperature changes in the opposite direction, the contamination factor decrease rate is less than the preset threshold of the contamination factor decrease rate, or the tube wall temperature decrease rate is less than the preset threshold of the contamination factor decrease rate, the sootblowing safety signal flips.

[0050] The effective spatial range of the sootblower refers to the size of the area where the sootblower can reach and effectively remove the accumulated dust or slag. The effective range of the sootblower can be obtained based on the sootblower layout.

[0051] The sootblowing safety determination module is also used to: form a safety limit with the contamination factor start threshold, the contamination factor stop threshold, the contamination factor decrease rate preset threshold, the tube wall temperature upper limit and the tube wall temperature decrease rate preset threshold; if the heating surface tube wall temperature or the contamination factor in the current sootblower effective space range is not within the corresponding safety limit, an alarm signal is issued, the sootblowing efficiency test module and the sootblowing cost calculation module are terminated, the normal continuous sootblowing function is activated, and the test and calculation results are marked as invalid.

[0052] Further, combined with Figure 3 , the sootblowing efficiency test module 102 will be described in detail as follows.

[0053] According to the arrangement of the sootblower on the boiler heating surface, a suitable sootblowing test strategy is selected, different sootblowing variable parameters are set (variable parameters include different sootblowing power source output adjustment, different power source sootblowing devices, sootblowing time and different unit loads), and tests are carried out one by one to ensure that all sootblowing methods can be covered. The different sootblowing power sources can be steam sootblowing with steam extraction from two different parts, or can be a steam plus other non-steam medium sootblowing. During the test, the real-time coal-fired generator set power threshold is divided into several load condition branches. In each load condition branch, starting from the single variable test link, the sootblowing power source output adjustment is changed to obtain the effective sootblowing time length of different output adjustment amounts, and the sootblowing test and cost coefficient set of a single sootblowing power source are realized; after completing all single variable tests, enter the multivariable test link, change the output adjustment amount of each sootblowing power source when different sootblowing power sources are working at the same time, and carry out sootblowing tests to obtain the effective sootblowing time length of different output adjustment amounts, and realize the sootblowing test and cost coefficient set when two or more sootblowing power sources are working at the same time. The effective sootblowing time length is generated when the deviation between the actual contamination factor and the supremum of the contamination factor is less than a preset threshold and the time is delayed by a preset time length threshold.

[0054] During the above test process, process data is collected in real time through the industrial control system or other measurement and recording methods to form a sootblowing relationship database, including a set of unit heat consumption parameters (including unit load, steam inlet volume of the steam turbine, pressure and temperature of the main steam, boiler feed water volume, boiler feed water pressure and temperature, reheat steam volume, cold section reheat steam pressure and temperature, hot section reheat steam pressure and temperature, boiler feed water volume, boiler feed water pressure and temperature, etc.), a set of sootblowing energy consumption parameters (including sootblowing steam pressure, sootblowing steam temperature, sootblowing steam flow, sootblowing steam regulating valve position, sootblowing steam consumption, sootblowing steam pressure and temperature, sonic or other medium sootblower energy consumption parameters, sootblowing time, etc.), a set of working medium enthalpy parameters of each heating surface of the boiler (working medium includes boiler main steam, boiler feed water, reheat steam, sootblowing steam, desuperheating water, etc.), a set of contamination factor parameters of each heating surface of the boiler, and a set of effective sootblowing time parameters of each heating surface of the boiler under various sootblowing conditions.

[0055] The working fluid enthalpy of 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 can be DCS, SCADA, PLC, etc.).

[0056] The test process will be described below using steam soot blowing using steam extraction from two different locations and a combination of steam soot blowing and sonic soot blowing as examples.

[0057] 1. When steam soot blowing with steam extracted from two different parts is used, the following soot blowing test unit can be used in the soot blowing efficiency test module.

[0058] Step 1: Under the current unit load condition, open the first sootblowing source steam pressure regulating valve with a certain step value (change the sootblowing steam pressure accordingly) to conduct a boiler heating surface sootblowing test.

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

[0060] Step 2: Under the current unit load condition, close the steam pressure regulating valve from the first sootblowing source, and open the steam pressure regulating valve from the second sootblowing source with a certain step value (correspondingly change the sootblowing steam pressure) to carry out sootblowing on the boiler heating surface.

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

[0062] (1) The steam pressure regulating valve of the first sootblowing source is opened to a step value and maintained at an opening, and the steam pressure regulating valve of the second sootblowing source is opened at a certain step value to perform sootblowing on the boiler heating surface.

[0063] (2) The steam pressure regulating valve of the first sootblowing source is opened to two step values ​​and maintained at the opening degree, and the steam pressure regulating valve of the second sootblowing source is opened at a certain step value to perform sootblowing on the boiler heating surface.

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

[0065] (4) The steam pressure regulating valve from the second sootblowing source is opened to a step value and maintained at an opening, and the steam pressure regulating valve from the first sootblowing source is opened at a certain step value to perform sootblowing on the boiler heating surface.

[0066] (5) The steam pressure regulating valve from the second sootblowing source is opened to two step values ​​and maintained at an opening degree, and the steam pressure regulating valve from the first sootblowing source is opened at a certain step value to perform sootblowing on the boiler heating surface.

[0067] (6) Repeat steps (4) and (5) until the steam pressure regulating valve of the second sootblowing source is fully opened.

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

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

[0070] 2. When a combination of steam sootblowing and sonic sootblowing is used, the following sootblowing test unit can be used in the sootblowing efficiency test module.

[0071] Step 1: Under the current unit load condition, open the sootblowing steam pressure regulating valve at a certain step value (change the sootblowing steam pressure accordingly) to carry out sootblowing on the boiler heating surface.

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

[0073] Step 3: Mixed soot blowing test.

[0074] (1) The sootblowing steam pressure regulating valve is opened to a step value and maintained at the opening, and the sonic sootblowing is started to blow soot on the boiler heating surface.

[0075] (2) The sootblowing steam pressure regulating valve is opened to two step values ​​and maintained at the opening, and the sonic sootblowing is started to blow soot on the boiler heating surface.

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

[0077] (4) Repeat the above steps (1), (2) and (3) to adjust the load range of different units.

[0078] As above, when each step of the soot blowing test is performed, when the deviation between the actual contamination factor and the upper bound of the contamination factor is less than the preset threshold, the test is stopped after a delay of a preset threshold time.

[0079] Furthermore, the effective sootblowing cost calculation module 103 will be described in detail as follows.

[0080] The sootblowing cost is calculated based on the sootblowing relationship database obtained during the above-mentioned sootblowing efficiency test, including the unit heat consumption parameter set, sootblowing energy consumption parameter set, boiler heating surface working fluid enthalpy parameter set and effective sootblowing time parameter set.

[0081] According to the principle of thermal power plants, when the power generation capacity is constant, when the unit is sootblowing, the benefits of increasing the boiler heat load and reducing the turbine heat consumption are greater than the loss caused by sootblowing energy consumption. As the sootblowing time increases, the growth of sootblowing benefits will become slower and slower, and eventually the increase in energy consumption will exceed the benefits of sootblowing. By calculating the sootblowing cost of the sootblowing relationship database obtained from the sootblowing test, the maximum value of the net sootblowing benefit P can be found. max , and the soot blowing benefit is P max ~0 is the economic feasible region for sootblowing.

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

[0083] P in =P Qb ;P Qb =Q b ×t s ;

[0084] Among them, P net is the net soot blowing income; P in Total benefit brought by soot blowing for the unit; P Qb Benefits from reduced heat consumption of steam turbine and increased heat load of boiler; s It is the effective soot blowing time.

[0085] P out =P D1

[0086] Among them, P out is the soot blowing energy loss, P D1 Indicates the energy loss of sootblowing.

[0087] The economic feasible region of sootblowing is:

[0088] The benefits brought by the increase of boiler heat load + the benefits brought by the reduction of turbine heat consumption - the energy loss of soot blowing > 0.

[0089] Specifically, when there is sootblowing fluid loss, the heat consumption of the steam turbine Q0 and the heat load of the boiler 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, kg / h; h0: main steam enthalpy, kJ / kg; h fw : Boiler main feed water enthalpy, kJ / kg; D rh : Reheat steam quantity, kg / h; h rh ": reheating hot section steam enthalpy, kJ / kg; h rh ': reheat cold section steam enthalpy, kJ / kg; Ds n : The amount of steam consumed by sootblowing with different extraction steam sources, kg / h; h n Sootblowing steam enthalpy value of different extraction steam sources, kJ / kg; D w : Desuperheating water volume, kg / h; h w : Desuperheating water enthalpy, kJ / kg; h ma : enthalpy of water supplement, kJ / kg.

[0094] The soot blowing energy loss 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 the soot blowing energy loss; t sn Indicates the duration of soot blowing with different extraction steam sources; E m Indicates the energy consumption parameters of other medium soot blowers; K m Indicates the conversion coefficient of other medium sootblower energy consumption parameters into energy unit kilojoule; t sm Indicates the duration of soot blowing by other medium soot blowers; m and n are both greater than or equal to 1.

[0097] Furthermore, the sootblowing guidance module 104 finds the best economic operation mode of the sootblowing system by comparing in real time whether the sootblowing system cost of the coal-fired power generation unit is within the effective sootblowing cost range, and can propose an optimized sootblowing guidance method according to the actual operating conditions of the unit to effectively guide the on-site sootblowing method.

[0098] Specifically, when the sootblowing cost (net sootblowing benefit) is close to 0 or even less than 0, it means that the total benefit brought by the sootblowing of the unit is less than the energy loss of sootblowing, and a corresponding alarm is issued to remind the operating personnel to stop sootblowing and check whether there is leakage and other losses in the sootblowing system.

[0099] In different load ranges, the operator is prompted to select a suitable sootblowing source and a mixed steam supply with a suitable sootblowing steam source opening to sootblow the heating surface to obtain greater benefits. That is, the third step of the sootblowing test unit described above is to test which sootblowing source is more suitable for different load ranges, that is, the sootblowing source with greater sootblowing benefits in different load ranges.

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

[0101] S401, when the unit load is stable, when the contamination factor of each heating surface is higher than the start threshold, the corresponding soot blower is started for soot blowing, and when the contamination factor of each heating surface is lower than the stop threshold, the corresponding soot blower stops soot blowing. During the soot blowing process, the heating surface tube wall temperature and contamination factor of the current effective space range of the soot blower are judged. If they are within their respective safety limit ranges, the current soot blowing safety signal is output; the safety limit 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 safety limit 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 iteratively generated by the soot blowing safety judgment module online collecting multiple soot blowing process data of the unit heating surface, and the generation indicates that the soot blowing safety judgment module is activated and effective;

[0102] S402, after the sootblowing safety determination module is activated and becomes effective, the sootblowing modes preset based on the arrangement of the sootblower on the heating surface of the boiler are tested one by one, and the test data of each test is recorded to form a sootblowing relationship database; the sootblowing mode includes, for each load condition branch divided according to the real-time coal-fired power generation unit electric power threshold, single variable test and multivariate test are respectively performed based on the sootblowing power source output adjustment amount; the sootblowing relationship database includes the unit heat consumption parameter set, the sootblowing energy consumption parameter set, the boiler heating surface working medium enthalpy parameter set, the boiler heating surface contamination factor parameter set and the effective sootblowing time parameter set under various sootblowing conditions for each heating surface of the boiler;

[0103] S403, after the sootblowing safety determination module is activated and becomes effective, the difference between the total benefit brought by the sootblowing of the computer group and the energy loss of sootblowing is calculated according to the sootblowing relationship database obtained during the test process to obtain the net benefit of sootblowing; the total benefit brought by the sootblowing of the unit includes the benefit brought by the reduction of the heat consumption of the steam turbine and the increase of the heat load of the boiler;

[0104] S404: After the effective sootblowing cost calculation module is iterated, an optimized sootblowing method is output according to the net sootblowing benefit.

[0105] Specific implementation of a boiler sootblowing test and optimization method The same boiler sootblowing test and optimization system is not repeatedly described in this embodiment.

[0106] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above invention concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other to form a technical solution.

Claims

1. A boiler sootblowing test and optimization system, characterized in that: include: The sootblowing safety judgment module is used to start the corresponding sootblower for sootblowing when the contamination factor of each heating surface is higher than the start threshold under the condition of stable unit load, and stop the sootblowing of the corresponding sootblower when the contamination factor of each heating surface is lower than the stop threshold. During the sootblowing process, the heating surface tube wall temperature and contamination factor of the current sootblower effective space range are judged, and if they are within their respective safety limit ranges, the current sootblowing safety signal is output; The safety limit range of the tube wall temperature of the heating surface is based on the upper limit of the tube wall temperature and the preset threshold of the tube wall temperature drop rate; 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 of the contamination factor drop rate, and each threshold is iteratively generated by the sootblowing safety judgment module online collecting multiple sootblowing process data of the heating surface of the unit, and the generation indicates that the sootblowing safety judgment module is activated and effective; A sootblowing efficiency test module is used to test the sootblowing modes preset based on the arrangement of the sootblower on the heating surface of the boiler one by one after the sootblowing safety determination module is activated and becomes effective, record the test data of each test, and form a sootblowing relationship database; the sootblowing mode includes single variable test and multivariate test based on the output adjustment amount of the sootblowing power source for each load condition branch divided according to the real-time coal-fired power generation unit electric power threshold; the sootblowing relationship database includes a unit heat consumption parameter set, a sootblowing energy consumption parameter set, a boiler heating surface working medium enthalpy parameter set, a boiler heating surface contamination factor parameter set, and a boiler heating surface effective sootblowing time parameter set under various sootblowing conditions for each heating surface of the boiler; The effective sootblowing cost calculation module is used to calculate the difference between the total benefit brought by the sootblowing of the unit and the energy loss of sootblowing according to the sootblowing relationship database obtained during the test process after the sootblowing safety judgment module is activated and becomes effective, so as to obtain the net benefit of sootblowing; the total benefit brought by the sootblowing of the unit includes the benefit brought by the reduction of the heat consumption of the steam turbine and the increase of the heat load of the boiler; The sootblowing guidance module is used to output the optimized sootblowing method according to the net sootblowing benefit after the iteration of the effective sootblowing cost calculation module is completed.

2. The boiler sootblowing test and optimization system according to claim 1, characterized in that: The sootblowing safety determination module is also used to: if the heating surface tube wall temperature or contamination factor of the current sootblower effective space range is not within the corresponding safety limit range, an alarm signal is issued, the sootblowing efficiency test module and the sootblowing cost calculation module are terminated, the normal continuous sootblowing function is activated, and the test and calculation results are marked as invalid.

3. The boiler sootblowing test and optimization system according to claim 1, characterized in that: Based on the safety interval formed by the start threshold and stop threshold of the same contamination factor, in each load condition branch, starting from the single-variable test link, the output adjustment amount of the sootblowing power source is changed to obtain the effective sootblowing time with different output adjustment amounts, thereby realizing the sootblowing test of a single sootblowing power source and the acquisition of the sootblowing relationship database; after completing all single-variable tests, the multi-variable test link is entered, and the output adjustment amount of each sootblowing power source is changed when different sootblowing power sources are working at the same time, and a sootblowing test is performed to obtain the effective sootblowing time with different output adjustment amounts, thereby realizing the sootblowing test and the acquisition of the sootblowing relationship database when two or more sootblowing power sources are working at the same time.

4. The boiler sootblowing test and optimization system according to claim 1, characterized in that: The effective sootblowing time is generated when the actual contamination factor decreases to a value less than a preset threshold value from the contamination factor stop threshold value and is delayed by a preset time threshold value.

5. The boiler sootblowing test and optimization system according to claim 1, characterized in that: The different sootblowing power sources include two or more steam sootblowing with steam extracted from different parts or one type of steam plus other non-steam media sootblowing.

6. The boiler sootblowing 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 by applying the enthalpy calculation function block of the industrial control system based on the real-time pressure and temperature of the working fluid.

7. The boiler sootblowing test and optimization system according to claim 1, characterized in that: The benefit brought by the reduction of the heat consumption of the steam turbine is equal to the product of the heat consumption of the steam turbine and the effective sootblowing time; the benefit brought by the increase of the heat load of the boiler is equal to the product of the heat load of the boiler and the effective sootblowing time.

8. The boiler sootblowing test and optimization system according to claim 1, characterized in that: The soot blowing energy loss 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 the soot blowing energy loss; Ds n Indicates the amount of steam consumed by soot blowing from different extraction steam sources per unit time; h n Indicates the enthalpy value of sootblowing steam from different extraction steam sources; t sn Indicates the duration of soot blowing with different extraction steam sources; E m Indicates the energy consumption parameters of other medium soot blowers; K m Indicates the conversion coefficient of other medium sootblower energy consumption parameters into energy unit kilojoule; t sm Indicates the duration of soot blowing by other medium soot blowers; n and m are both greater than or equal to 1.

9. The boiler sootblowing test and optimization system according to claim 1, characterized in that: The sootblowing guidance module is specifically used for: The net sootblowing benefit is judged. When the net sootblowing benefit is greater than 0, the maximum value of the net sootblowing benefit in each sootblowing test is obtained, and the optimized sootblowing method is output to prompt the operating personnel to select a suitable sootblowing power source and the sootblowing power source output adjustment amount; when the net sootblowing benefit is less than or equal to 0, a stop sootblowing signal and / or an alarm signal is output.

10. A boiler sootblowing test and optimization method, characterized in that: include: Under the condition of stable unit load, when the contamination factor of each heating surface is higher than the start threshold, the corresponding soot blower is started for soot blowing; when the contamination factor of each heating surface is lower than the stop threshold, the corresponding soot blower stops soot blowing; during the soot blowing process, the heating surface tube wall temperature and contamination factor of the current soot blower effective space range are judged; if they are within their respective safety limit ranges, the current soot blowing safety signal is output; The safety limit range of the tube wall temperature of the heating surface is based on the upper limit of the tube wall temperature and the preset threshold of the tube wall temperature drop rate; 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 of the contamination factor drop rate, and each threshold is iteratively generated by the sootblowing safety judgment module online collecting multiple sootblowing process data of the heating surface of the unit, and the generation indicates that the sootblowing safety judgment module is activated and effective; After the sootblowing safety determination module is activated and becomes effective, the sootblowing modes preset based on the arrangement of the sootblower on the boiler heating surface are tested one by one, and the test data of each test is recorded to form a sootblowing relationship database; the sootblowing mode includes single variable test and multivariable test based on the output adjustment amount of the sootblowing power source for each load condition branch divided according to the real-time coal-fired power generation unit electric power threshold; the sootblowing relationship database includes the unit heat consumption parameter set, the sootblowing energy consumption parameter set, the boiler heating surface working medium enthalpy parameter set, the boiler heating surface contamination factor parameter set and the effective sootblowing time parameter set under various sootblowing conditions for each heating surface of the boiler; After the sootblowing safety determination module is activated and becomes effective, the difference between the total benefit brought by the sootblowing of the computer group and the energy loss of sootblowing is calculated according to the sootblowing relationship database obtained during the test process to obtain the net benefit of sootblowing; the total benefit brought by the sootblowing of the unit includes the benefits brought by the reduction of the heat consumption of the steam turbine and the increase of the heat load of the boiler; After the iteration of the effective sootblowing cost calculation module is completed, the optimized sootblowing method is output according to the net sootblowing benefit.

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