Coal power unit control method and device, storage medium and unit

Abstract

The invention provides a coal power unit control method and device, a storage medium and a unit, and relates to the technical field of power generation equipment.According to the scheme, after boiler loads are obtained, the fuel quantity and the total ammonia doping amount set value are determined based on a sliding pressure curve, and the coal combustion amount set value is obtained through calculation based on the fuel quantity and the total ammonia doping amount set value; calculating the total oxygen demand based on the coal combustion amount set value and the total ammonia doping amount set value, controlling the opening degree of the air supply movable blade based on the total oxygen demand, enabling the unit to provide enough air for the boiler, and dynamically configuring PID parameters based on the total ammonia doping amount set value, so as to achieve the purpose of controlling the opening degree of the air supply movable blade. The opening degree of the second-stage desuperheating water adjusting valve is dynamically corrected based on the dynamically configured PID parameters, so that the main steam temperature is kept within a certain range, and the problem that the main steam temperature changes drastically under the variable load working condition is solved.

Description

Technical Field

[0001] This invention relates to the field of power generation equipment manufacturing technology, specifically to a control method, device, storage medium, and unit for coal-fired power units. Background Technology

[0002] Green ammonia co-firing is a technology that synthesizes green ammonia from green hydrogen produced by renewable energy sources (such as wind and solar power) and nitrogen, and then blends it into coal-fired power plant boilers at a certain ratio (such as 10%-35%) to achieve low-carbon power generation. Its core lies in utilizing the zero-carbon property of green ammonia combustion, which produces only nitrogen and water vapor. Each ton of green ammonia co-firing can replace approximately 1.7 tons of coal and reduce carbon dioxide emissions by 4.2 tons. Therefore, green ammonia co-firing has become a major implementation path for the low-carbon construction and retrofitting of coal-fired power plants. However, the existing scheme uses fixed PID control parameters during the control process, which cannot be dynamically adjusted according to the amount of ammonia co-firing, causing the main steam temperature to deviate from the set value under variable load conditions. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a coal-fired power unit control method, device, storage medium, and unit to keep the main steam temperature of the coal-fired power unit stable.

[0004] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0005] A control method for a coal-fired power unit, comprising:

[0006] Obtain boiler load and sliding pressure curves;

[0007] The set values ​​for fuel quantity and total ammonia blending are determined based on the boiler load and sliding pressure curve.

[0008] The coal consumption setpoint is calculated based on the fuel quantity and the total ammonia blending setpoint.

[0009] The total oxygen demand is calculated based on the aforementioned coal consumption setpoint and total ammonia blending setpoint.

[0010] Adjust the opening of the blower blades of the coal-fired power unit based on the total oxygen demand;

[0011] Obtain PID parameters that match the total ammonia blending setpoint, and use the PID parameters to dynamically correct the opening of the secondary desuperheating water regulating valve based on the total ammonia blending setpoint. The secondary desuperheating water regulating valve is used to inject cooling medium into the desuperheater of the coal-fired power unit to reduce the main steam temperature.

[0012] Optionally, in the above-mentioned coal-fired power unit control method, determining the set values ​​for fuel quantity and total ammonia blending based on the boiler load and sliding pressure curve includes:

[0013] The required boiler input calorific value and carbon emission reduction ratio are determined based on the boiler load and sliding pressure curve, wherein the sliding pressure curve is marked with the required boiler input calorific value and carbon emission reduction ratio corresponding to different boiler loads.

[0014] The fuel quantity is determined based on the required boiler input calorific value, and the total ammonia blending amount is set based on the boiler input calorific value and the carbon emission reduction ratio.

[0015] Optionally, in the above-mentioned coal-fired power unit control method, the calculation of the coal consumption setpoint based on the fuel quantity and total ammonia blending setpoint includes:

[0016] Calculate the equivalent fuel quantity corresponding to the total ammonia blending setpoint;

[0017] The difference between the fuel quantity and the equivalent fuel quantity is used as the coal consumption setting value.

[0018] Optionally, in the above-mentioned coal-fired power unit control method, calculating the total oxygen demand based on the setpoint for coal consumption and the setpoint for total ammonia blending includes:

[0019] The oxygen demand for coal is determined based on the aforementioned set value for coal consumption.

[0020] The oxygen demand for ammonia is determined based on the set value of the total ammonia content.

[0021] The sum of the oxygen demand for coal combustion and the oxygen demand for ammonia blending is taken as the total oxygen demand.

[0022] Optionally, in the above-mentioned coal-fired power unit control method, after obtaining the total ammonia blending setpoint, the method further includes:

[0023] Obtain the differential pressure deviation of the main steam pressure;

[0024] The main steam pressure corresponding to the boiler load is determined based on the sliding pressure curve.

[0025] When the boiler load changes, the main steam pressure is adjusted in advance based on the differential pressure deviation.

[0026] Optionally, in the above-mentioned coal-fired power unit control method, the sum of the oxygen demand for coal combustion and the oxygen demand for ammonia blending is taken as the total oxygen demand, including:

[0027] Obtain the oxygen concentration in the unit's flue gas;

[0028] Obtain a first correction factor for the oxygen demand of coal combustion and a second correction factor for the oxygen demand of ammonia-added coal combustion based on the oxygen concentration;

[0029] The oxygen demand for coal combustion is corrected based on the first correction coefficient, and the oxygen demand for ammonia blending is corrected based on the second correction coefficient.

[0030] The total oxygen demand is the sum of the corrected oxygen demand for coal combustion and the corrected oxygen demand for ammonia blending.

[0031] A coal-fired power unit control device, comprising:

[0032] The boiler main control unit is used to acquire the boiler load and sliding pressure curve, and determine the fuel quantity and total ammonia blending setpoint based on the boiler load and sliding pressure curve;

[0033] The fuel control unit is used to calculate the coal consumption setpoint based on the fuel quantity and the total ammonia blending setpoint.

[0034] The air supply volume optimization unit is used to calculate the total oxygen demand based on the set value of the coal consumption and the set value of the total ammonia content, and to adjust the opening of the air supply blades of the coal-fired power unit based on the total oxygen demand.

[0035] The main steam parameter control unit is used to acquire PID parameters that match the total ammonia blending setpoint. The PID parameters are used to dynamically correct the opening of the secondary desuperheating water regulating valve based on the total ammonia blending setpoint. The secondary desuperheating water regulating valve is used to inject cooling medium into the desuperheater of the coal-fired power unit to reduce the main steam temperature.

[0036] A coal-fired power unit controller, comprising:

[0037] At least one processing device and a storage device connected to the processing device, wherein:

[0038] The storage device is used to store computer programs;

[0039] The processing device is used to execute the computer program so that the coal-fired power unit controller can implement any of the above-mentioned coal-fired power unit control methods.

[0040] A coal-fired power unit system includes the aforementioned coal-fired power unit controller.

[0041] Optionally, the aforementioned coal-fired power unit system also includes:

[0042] Liquid ammonia evaporator, buffer tank, ammonia main pipe pressure regulating valve, ammonia main pipe, ammonia main pipe flow regulating valve, ammonia branch pipe, ammonia branch pipe flow regulating valve, burner and boiler;

[0043] The ammonia outlet of the liquid ammonia evaporator is connected to the ammonia inlet of the buffer tank;

[0044] The ammonia outlet of the buffer tank is connected to the burner via an ammonia main pipe and an ammonia branch pipe connected to the ammonia main pipe.

[0045] The ammonia main pipe pressure regulating valve and the ammonia main pipe flow regulating valve are installed on the ammonia main pipe.

[0046] The ammonia branch pipe flow regulating valve is installed on the ammonia branch pipe.

[0047] The ammonia outlet of the ammonia branch pipe is connected to the ammonia inlet of the boiler.

[0048] The ammonia main pipe pressure regulating valve, the ammonia main pipe flow regulating valve, and the ammonia branch pipe flow regulating valve are connected to the control signal output terminal of the coal-fired power unit controller.

[0049] Based on the above technical solution, the solution provided in this embodiment of the invention determines the fuel quantity and total ammonia blending setpoints based on the sliding pressure curve after obtaining the boiler load. It then calculates the coal quantity setpoint based on these setpoints and calculates the total oxygen demand based on both the coal quantity setpoint and the total ammonia blending setpoint. Finally, it controls the opening of the blower blades based on the total oxygen demand, ensuring the unit can provide sufficient air to the boiler. Simultaneously, it dynamically configures PID parameters based on the total ammonia blending setpoint and dynamically corrects the opening of the secondary desuperheating water regulating valve based on these dynamically configured PID parameters, thereby maintaining the main steam temperature within a certain range and preventing drastic changes in main steam temperature under variable load conditions. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0051] Figure 1 A flowchart illustrating a coal-fired power unit control method provided in an embodiment of this application;

[0052] Figure 2 This is a schematic diagram of the structure of a coal-fired power unit control device provided in an embodiment of this application;

[0053] Figure 3 This is a schematic diagram of the structure of a coal-fired power unit system provided in an embodiment of this application. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] See Figure 1The coal-fired power unit control method disclosed in this application may include:

[0056] Step S101: Obtain boiler load and sliding pressure curves.

[0057] The boiler load can be obtained through grid load mapping. In this scheme, the grid load command can be obtained first, parsed to obtain the grid load, and then the boiler load matching the grid load can be obtained. The sliding pressure curve is a pre-constructed curve that describes the adjustment of the main steam pressure with changes in boiler load when the boiler is operating under varying load.

[0058] Step S102: Determine the fuel quantity and total ammonia blending setpoints based on the boiler load and sliding pressure curve.

[0059] The required boiler input calorific value and carbon emission reduction ratio are preset for the boiler to operate under various boiler loads. Based on the carbon emission reduction ratio, the total ammonia addition setting value of the boiler can be determined. This application can pre-write the correspondence between the boiler input calorific value, carbon emission reduction ratio and boiler load into the sliding pressure curve.

[0060] This solution monitors the boiler load in real time, then determines the boiler input calorific value and total ammonia blending setpoint corresponding to the boiler load based on the sliding pressure curve. The corresponding fuel quantity is calculated based on the boiler input calorific value; when the unit uses coal as fuel, the fuel quantity refers to the coal consumption. The total ammonia blending setpoint is calculated based on the carbon emission reduction ratio. When calculating the total ammonia blending setpoint based on the carbon emission reduction ratio, the required calorific value of ammonia is calculated based on the carbon emission reduction ratio and the boiler input calorific value. The amount of ammonia that can provide this calorific value is then further calculated; this amount of ammonia is the total ammonia blending setpoint.

[0061] Step S103: Calculate the coal consumption setting value based on the fuel quantity and the total ammonia blending setting value.

[0062] After calculating the fuel quantity and total ammonia blending setpoint, it is necessary to calculate the coal consumption setpoint required for the coal-fired power unit to operate. This requires first calculating the equivalent fuel quantity to the total ammonia blending setpoint, denoted as the equivalent fuel quantity. For example, when the fuel is coal, the equivalent fuel quantity is the amount of coal with the same calorific value as the ammonia quantity in the total ammonia blending setpoint. Once the equivalent fuel quantity is determined, the difference between the fuel quantity and the equivalent fuel quantity is taken as the coal consumption setpoint. The coal consumption setpoint is recorded as the weight of coal supplied to the boiler per unit time during the operation of the coal-fired power unit.

[0063] Step S104: Calculate the total oxygen demand based on the set value of coal consumption and the set value of total ammonia blending.

[0064] In this step, after calculating the set value of coal consumption, the oxygen demand required for the coal to fully burn the set value is calculated based on the coal combustion efficiency and the combustion formula. The oxygen demand required for ammonia to fully burn the set value of total ammonia content is calculated based on the ammonia combustion formula. The sum of the coal oxygen demand and the ammonia oxygen demand is taken as the total oxygen demand.

[0065] Step S105: Adjust the opening of the blower blades of the coal-fired power unit based on the total oxygen demand.

[0066] Since the oxygen content in the air is constant, once the total oxygen demand is determined, the air flow rate that needs to be injected into the boiler is also determined. The air flow rate is determined by the opening degree of the blower blades of the coal-fired power unit. Therefore, in order to provide sufficient oxygen to the boiler, it is necessary to calculate the blower blade opening value that matches the total oxygen demand and control the blower blade opening degree based on the blower blade opening value.

[0067] Step S106: Obtain PID parameters that match the total ammonia blending setpoint, and use the PID parameters to dynamically correct the opening of the secondary desuperheating water regulating valve based on the total ammonia blending setpoint. The secondary desuperheating water regulating valve is used to inject cooling medium into the desuperheater of the coal-fired power unit to reduce the main steam temperature.

[0068] In coal-fired power units, ammonia blending combustion, as a low-carbon fuel technology, places certain demands on the main steam temperature. Ammonia blending significantly alters the boiler's combustion characteristics, leading to increased flue gas temperature at the furnace outlet and a shift in the flame center, thereby increasing the heat absorption of the convective superheater and increasing the risk of rising main steam temperature. While traditional two-stage desuperheating water regulation can stabilize steam temperature, it suffers from response lag and struggles to adapt to the dynamic disturbances of ammonia blending combustion. Therefore, this solution dynamically adjusts the opening of the two-stage desuperheating water regulating valve based on the ammonia blending amount, reliably suppressing the risk of main steam overheating. Specifically, the total ammonia blending amount setpoint is used as a feedforward signal to predict its impact on the main steam temperature trend in advance. When the total ammonia blending amount setpoint increases, the system increases the flow rate of the two-stage desuperheating water to offset the rise in main steam temperature caused by combustion disturbances; conversely, it reduces the injection of desuperheating water to avoid overcooling, thus ensuring that the main steam temperature remains within a reliable range. Furthermore, since the total ammonia blending setpoint is based on the boiler load changing at any time, in order to further improve the stability of the main steam temperature, this application can dynamically optimize the PID parameters based on the total ammonia blending setpoint, and then use the PID parameters to dynamically correct the opening of the secondary desuperheating water regulating valve based on the total ammonia blending setpoint.

[0069] The above-described scheme disclosed in this application determines the fuel quantity and total ammonia blending setpoints based on the sliding pressure curve after obtaining the boiler load. It then calculates the coal quantity setpoint based on these setpoints and calculates the total oxygen demand. Finally, it controls the opening of the blower blades based on the total oxygen demand, ensuring the unit provides sufficient air to the boiler. Simultaneously, it dynamically configures PID parameters based on the total ammonia blending setpoint and dynamically corrects the opening of the secondary desuperheating water regulating valve based on these parameters, maintaining the main steam temperature within a certain range and preventing drastic temperature changes under variable load conditions.

[0070] The carbon emission reduction ratio is a key indicator for measuring the degree of reduction in carbon dioxide emissions during boiler operation. When a boiler operates under varying loads, carbon emissions can be effectively reduced by adjusting parameters such as the main steam pressure (following the sliding pressure curve) and employing energy-saving and emission-reduction technologies (such as ammonia-blended combustion). The carbon emission reduction ratio is the percentage reduction in carbon dioxide emissions achieved through these technologies. Users can pre-configure the correspondence between boiler load and the carbon emission reduction ratio; different boiler loads may correspond to different carbon emission reduction ratios. The correspondence between the boiler load and the carbon emission reduction ratio can also be determined by the sliding pressure curve. Therefore, in this embodiment, when determining the fuel quantity and total ammonia blending setpoint based on the boiler load and the sliding pressure curve, it may specifically include obtaining the power grid load command, determining the boiler load in the coal-fired power unit based on the power grid load in the power grid load command (where the larger the power grid load, the larger the boiler load), determining the required boiler input calorific value and carbon emission reduction ratio based on the boiler load and the sliding pressure curve (where the boiler input calorific value is the calorific value that the fuel to be supplied to the boiler can provide), where the sliding pressure curve marks the required boiler input calorific value and carbon emission reduction ratio corresponding to different boiler loads; determining the fuel quantity based on the required boiler input calorific value (where the fuel quantity is the amount of coal to be burned), and recording the ratio of the boiler input calorific value to the calorific value that can be provided by a unit weight of coal as the fuel quantity. The total ammonia blending amount is determined based on the boiler input calorific value and the carbon emission reduction ratio. The total ammonia blending amount is the amount of ammonia gas required to be supplied to the boiler in order to achieve the carbon emission reduction ratio. When calculating the total ammonia blending amount, the boiler input calorific value is multiplied by the carbon emission reduction ratio and then divided by the calorific value that ammonia gas can provide per unit weight.

[0071] In this embodiment, the coal consumption setpoint is the amount of coal required for the boiler to operate, and the coal consumption setpoint can be calculated in the following way:

[0072] ① First, calculate the equivalent fuel quantity corresponding to the total ammonia blending setting value. That is, in this scheme, based on the basic principle of the same calorific value, the total ammonia blending setting value is equivalent to the weight of coal that can provide the same calorific value. The equivalent weight of coal is the equivalent fuel quantity. Then, the difference between the fuel quantity and the equivalent fuel quantity is taken as the coal quantity setting value.

[0073] ② Coal consumption = fuel consumption × (1 - carbon emission reduction ratio) / calorific value provided by coal per unit weight.

[0074] Once the set values ​​for coal consumption and total ammonia blending are determined, the total oxygen demand during boiler operation needs to be calculated based on these values. The total oxygen demand is the amount of oxygen required to fully combust the coal and ammonia at the set values. Since the combustion formulas for coal and ammonia are different, this application can calculate the oxygen demand for coal and ammonia respectively based on their respective combustion formulas and masses. The sum of these oxygen demands is then used as the total oxygen demand. To quickly calculate the total oxygen demand, the application can pre-establish a correspondence between the oxygen demand for coal and the set values ​​for coal consumption, and between the oxygen demand for ammonia and the set values ​​for total ammonia blending. This correspondence is stored in a pre-defined mapping table. Once the set values ​​for coal consumption and total ammonia blending are determined, the oxygen demand for coal and ammonia blending can be quickly determined by looking up these tables.

[0075] In this embodiment, the boiler load on the sliding pressure curve also corresponds to the main steam pressure, and different loads may correspond to different main steam pressures. When the boiler is operating, the main steam pressure inside the boiler can be determined by the main steam temperature. The pressure deviation differential of the main steam pressure can be determined using the main steam temperature. When the boiler load changes, the main steam pressure corresponding to the boiler load is determined based on the sliding pressure curve, and the main steam pressure can be adjusted in advance based on the pressure deviation differential to prevent overshoot and improve the stability and response speed of the main steam pressure. For example, when the main steam pressure determined based on the sliding pressure curve is A, if the current main steam pressure inside the boiler measured based on the pressure deviation differential is already A, then no adjustment of the main steam pressure is needed. If there is a deviation in the current main steam pressure measured based on the pressure deviation differential, the main steam pressure is adjusted based on the deviation between the two.

[0076] In this embodiment, when the combustion of coal and ammonia is incomplete, a large amount of flue gas is generated. To ensure more complete combustion of coal and flue gas, the oxygen supply needs to be increased, i.e., the total oxygen demand needs to be increased, so that the oxygen supply exceeds the oxygen demand during the combustion of coal and ammonia. At this time, the oxygen concentration of the flue gas generated during the unit's operation can be monitored in real time. Then, a first correction coefficient and a second correction coefficient matching the oxygen concentration are obtained (the correspondence between the oxygen concentration and the first and second correction coefficients is pre-established). The oxygen demand for coal combustion is then corrected based on the first correction coefficient, and the oxygen demand for ammonia blending is corrected based on the second correction coefficient. The sum of the corrected oxygen demand for coal combustion and the corrected oxygen demand for ammonia blending is taken as the total oxygen demand. Alternatively, a third correction coefficient matching the oxygen concentration can be obtained, and this third correction coefficient can be used to directly correct the total oxygen demand.

[0077] In this embodiment, the boiler control system involves multiple controllers. The gain of some controllers is related to the number of mills in operation of the coal-fired power unit and the total ammonia dosage setting. Therefore, after determining the total ammonia dosage setting, the number of mills in operation of the coal-fired power unit can be obtained, and the gain of each controller that matches the number of mills in operation and the total ammonia dosage setting can be obtained. The gain of each controller is then allocated to the corresponding controller.

[0078] Corresponding to the above method, this embodiment discloses a coal-fired power unit control device. For the specific working content of each unit, please refer to the content of the above method embodiment.

[0079] The coal-fired power unit control device provided in the embodiments of the present invention is described below. The coal-fired power unit control device described below can be referred to in correspondence with the coal-fired power unit control method described above. See also: [link to application] Figure 2 The device may include:

[0080] The boiler main control unit 10, corresponding to steps S101 and S102 in the above method, is used to acquire the boiler load and sliding pressure curve, and determine the fuel quantity and total ammonia blending setpoints based on the boiler load and sliding pressure curve. The boiler load is determined by the power grid load. The boiler main control unit 10 can also dynamically adjust the PID parameters according to the number of mills in operation and the total ammonia blending setpoints through a self-optimization algorithm, and assign the PID parameters to the coal feeder controller, so that the coal feeder controller controls the coal feeder speed through the PID parameters, so that the coal feeder can provide sufficient coal quantity.

[0081] The fuel control unit 20, corresponding to step S103 in the above method, is used to calculate the coal consumption setpoint based on the fuel quantity and the total ammonia blending setpoint. Corresponding to the above method, the fuel control unit 20 is also used to adjust the controller gain of each controller according to the number of mill units in operation and the total ammonia blending setpoint.

[0082] The air supply volume optimization unit 30, corresponding to steps S104 and S105 in the above method, is used to calculate the total oxygen demand based on the coal consumption setpoint and the total ammonia blending setpoint, and to adjust the air supply blade opening of the coal-fired power unit based on the total oxygen demand. The total oxygen demand is the sum of the coal consumption oxygen demand and the ammonia blending oxygen demand. The coal consumption oxygen demand is determined based on the coal consumption setpoint, and the ammonia blending oxygen demand is determined based on the total ammonia blending setpoint. Since the oxygen content in the air is measurable, the total oxygen demand can be equivalent to the total air volume setpoint (the total air supply volume per unit time). Therefore, after determining the total oxygen demand setpoint, the total oxygen demand setpoint can be mapped to the total air volume setpoint, and the air supply blade opening can be adjusted by an adaptive PID controller based on the total air volume setpoint to regulate the airflow entering the boiler.

[0083] The main steam parameter control unit 40, corresponding to step S106 in the above method, is used to dynamically correct the opening of the secondary desuperheating water regulating valve based on the total ammonia dosage setting. The secondary desuperheating water regulating valve is used to inject cooling medium into the desuperheater of the coal-fired power unit to reduce the main steam temperature. Specifically, when the total ammonia dosage setting increases, the opening of the secondary desuperheating water regulating valve is increased based on a preset proportional relationship. The main steam parameter control unit 40 is also used to improve the stability of the main steam pressure under load conditions by combining the sliding pressure curve with the differential feedforward of the pressure deviation. The differential feedforward of the pressure deviation is determined by the main steam parameter control unit 40 based on the main steam temperature data. The sliding pressure curve is configured with the main steam pressure corresponding to each boiler load. The differential feedforward of the pressure deviation can provide the trend of main steam pressure changes in advance. When the boiler load changes, the main steam pressure can be adjusted in advance based on the differential feedforward of the pressure deviation to prevent overshooting of the main steam pressure and improve the stability and response speed of the main steam pressure.

[0084] Corresponding to the above method, the above device may also include an oxygen correction unit 50, which is used to take the sum of the corrected oxygen demand of coal combustion and the corrected oxygen demand of ammonia as the total oxygen demand based on the oxygen concentration in the real-time flue gas, the first correction coefficient of the oxygen demand of coal combustion and the second correction coefficient of the oxygen demand of ammonia blending.

[0085] To ensure even distribution of ammonia to each burner in the unit, the aforementioned device may further include a tiered ammonia blending control unit 60. This unit distributes ammonia evenly to each burner and participates in the feedforward control of the liquid ammonia vaporization supply subsystem. Specifically, the tiered ammonia blending control unit can allocate the amount of ammonia supplied to each burner via the main pipe and branch pipe regulating valves according to the number of burner layers in operation and the operating mode (automatic / manual), ensuring that the ammonia blending amount deviation of each burner is within the allowable range (e.g., deviation ≤3%), thus achieving dynamic distribution of the ammonia blending amount. The liquid ammonia vaporization subsystem adjusts the opening of the pneumatic pressure regulating valve in real time according to changes in the main pipe pressure, maintaining the ammonia supply pressure stable within the set pressure range (e.g., ±5 kPa) to maintain the amount of ammonia supplied to the unit at the set total ammonia blending amount. The liquid ammonia evaporator outlet temperature is controlled via a feedforward-feedback composite control to ensure that the ammonia vaporization efficiency remains at a certain value (e.g., ammonia vaporization efficiency ≥98%), thereby achieving responsive control of the liquid ammonia vaporization and shortening the response time. Therefore, in this embodiment, the power grid load command boiler main control unit 10 is converted into a total ammonia blending setpoint by the internal function generator (f(x)) and output in two ways: one way is input to the boiler main control unit to participate in the feedforward compensation of fuel quantity and main steam parameters; the other way is input to the layered ammonia blending control unit 60 to distribute ammonia evenly to each burner through the layered ammonia blending control unit 60 and participate in the feedforward control of the liquid ammonia gasification supply subsystem.

[0086] Corresponding to the above methods, this application also discloses a coal-fired power unit controller, which includes at least one processing device and a storage device connected to the processing device, wherein: the storage device is used to store a computer program; the processing device is used to execute the computer program so that the coal-fired power unit controller can implement any of the above-described coal-fired power unit control methods.

[0087] A coal-fired power unit system includes the aforementioned coal-fired power unit controller 100, liquid ammonia evaporator 1, buffer tank 2, ammonia main pipe pressure regulating valve 3, ammonia main pipe 4, ammonia main pipe flow regulating valve 5, ammonia branch pipe 6, ammonia branch pipe flow regulating valve 7, burner 8, and boiler 9.

[0088] The ammonia outlet of the liquid ammonia evaporator 1 is connected to the ammonia inlet of the buffer tank 2.

[0089] The ammonia outlet of the buffer tank 2 is connected to the burner 8 through the ammonia main pipe 4 and the ammonia branch pipe 6 connected to the ammonia main pipe 4.

[0090] The ammonia main pipe pressure regulating valve and the ammonia main pipe flow regulating valve are installed on the ammonia main pipe.

[0091] The ammonia branch pipe flow regulating valve is installed on the ammonia branch pipe.

[0092] The ammonia outlet of the ammonia branch pipe is connected to the ammonia inlet of the boiler.

[0093] The ammonia main pipe pressure regulating valve, the ammonia main pipe flow regulating valve, and the ammonia branch pipe flow regulating valve are connected to the control signal output terminal of the coal-fired power unit controller.

[0094] For ease of description, the above system is described by dividing it into various modules based on their functions. Of course, in implementing this invention, the functions of each module can be implemented in one or more software and / or hardware components.

[0095] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0096] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0097] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0098] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover 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 limitations, 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.

[0099] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a coal-fired power unit, characterized in that, include: Obtain boiler load and sliding pressure curves; The set values ​​for fuel quantity and total ammonia blending are determined based on the boiler load and sliding pressure curve. The coal consumption setpoint is calculated based on the fuel quantity and the total ammonia blending setpoint. The total oxygen demand is calculated based on the aforementioned coal consumption setpoint and total ammonia blending setpoint. Adjust the opening of the blower blades of the coal-fired power unit based on the total oxygen demand; Obtain PID parameters that match the total ammonia blending setpoint, and use the PID parameters to dynamically correct the opening of the secondary desuperheating water regulating valve based on the total ammonia blending setpoint. The secondary desuperheating water regulating valve is used to inject cooling medium into the desuperheater of the coal-fired power unit to reduce the main steam temperature.

2. The coal-fired power unit control method according to claim 1, characterized in that, The determination of fuel quantity and total ammonia blending setpoints based on the boiler load and sliding pressure curves includes: The required boiler input calorific value and carbon emission reduction ratio are determined based on the boiler load and sliding pressure curve, wherein the sliding pressure curve is marked with the required boiler input calorific value and carbon emission reduction ratio corresponding to different boiler loads. The fuel quantity is determined based on the required boiler input calorific value, and the total ammonia blending amount is set based on the boiler input calorific value and the carbon emission reduction ratio.

3. The coal-fired power unit control method according to claim 1, characterized in that, The coal consumption setpoint is calculated based on the aforementioned fuel quantity and total ammonia blending setpoint, including: Calculate the equivalent fuel quantity corresponding to the total ammonia blending setpoint; The difference between the fuel quantity and the equivalent fuel quantity is used as the coal consumption setting value.

4. The coal-fired power unit control method according to claim 1, characterized in that, The total oxygen demand is calculated based on the aforementioned coal consumption setpoint and total ammonia blending setpoint, including: The oxygen demand for coal is determined based on the aforementioned set value for coal consumption. The oxygen demand for ammonia is determined based on the set value of the total ammonia content. The sum of the oxygen demand for coal combustion and the oxygen demand for ammonia blending is taken as the total oxygen demand.

5. The coal-fired power unit control method according to claim 1, characterized in that, After obtaining the total ammonia blending setpoint, the following steps are also included: Obtain the differential pressure deviation of the main steam pressure; The main steam pressure corresponding to the boiler load is determined based on the sliding pressure curve. When the boiler load changes, the main steam pressure is adjusted in advance based on the differential pressure deviation.

6. The coal-fired power unit control method according to claim 1, characterized in that, The sum of the oxygen demand for coal combustion and the oxygen demand for ammonia blending is taken as the total oxygen demand, including: Obtain the oxygen concentration in the unit's flue gas; Obtain a first correction factor for the oxygen demand of coal combustion and a second correction factor for the oxygen demand of ammonia-added coal combustion based on the oxygen concentration; The oxygen demand for coal combustion is corrected based on the first correction coefficient, and the oxygen demand for ammonia blending is corrected based on the second correction coefficient. The total oxygen demand is the sum of the corrected oxygen demand for coal combustion and the corrected oxygen demand for ammonia blending.

7. A control device for a coal-fired power unit, characterized in that, include: The boiler main control unit is used to acquire the boiler load and sliding pressure curve, and determine the fuel quantity and total ammonia blending setpoint based on the boiler load and sliding pressure curve; The fuel control unit is used to calculate the coal consumption setpoint based on the fuel quantity and the total ammonia blending setpoint. The air supply volume optimization unit is used to calculate the total oxygen demand based on the set value of the coal consumption and the set value of the total ammonia content, and to adjust the opening of the air supply blades of the coal-fired power unit based on the total oxygen demand. The main steam parameter control unit is used to acquire PID parameters that match the total ammonia blending setpoint. The PID parameters are used to dynamically correct the opening of the secondary desuperheating water regulating valve based on the total ammonia blending setpoint. The secondary desuperheating water regulating valve is used to inject cooling medium into the desuperheater of the coal-fired power unit to reduce the main steam temperature.

8. A coal-fired power unit controller, characterized in that, include: At least one processing device and a storage device connected to the processing device, wherein: The storage device is used to store computer programs; The processing device is used to execute the computer program so that the coal-fired power unit controller can implement the coal-fired power unit control method as described in any one of claims 1 to 6.

9. A coal-fired power unit system, characterized in that, Includes the coal-fired power unit controller as described in claim 8.

10. The coal-fired power unit system according to claim 9, characterized in that, Also includes: Liquid ammonia evaporator, buffer tank, ammonia main pipe pressure regulating valve, ammonia main pipe, ammonia main pipe flow regulating valve, ammonia branch pipe, ammonia branch pipe flow regulating valve, burner and boiler; The ammonia outlet of the liquid ammonia evaporator is connected to the ammonia inlet of the buffer tank; The ammonia outlet of the buffer tank is connected to the burner via an ammonia main pipe and an ammonia branch pipe connected to the ammonia main pipe. The ammonia main pipe pressure regulating valve and the ammonia main pipe flow regulating valve are installed on the ammonia main pipe. The ammonia branch pipe flow regulating valve is installed on the ammonia branch pipe. The ammonia outlet of the ammonia branch pipe is connected to the ammonia inlet of the boiler. The ammonia main pipe pressure regulating valve, the ammonia main pipe flow regulating valve, and the ammonia branch pipe flow regulating valve are connected to the control signal output terminal of the coal-fired power unit controller.

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