A method and system for partitioned variable-pole-distance and pulse coordination control of an electrostatic precipitator

Abstract

The method comprises the following steps: acquiring partition configuration information of an electric dust collector; matching a corresponding power supply mode based on the partition configuration information; collecting running electrical data, calculating an anti-corona characteristic index based on the running electrical data, and switching the power supply mode of the corresponding electric field; cooperatively optimizing the running power of each electric field to obtain a target power setting value of each electric field; and controlling each electric field to execute power adjustment and adjust the rapping cycle of the corresponding electric field. The present disclosure matches the corresponding power supply mode by configuring the inter-electrode distance and the cathode wire, thereby improving the dust removal efficiency and reducing the energy consumption; switches the power supply mode when the conditions are met, thereby inhibiting the anti-corona phenomenon; cooperatively optimizes the power supply mode, thereby realizing the reasonable distribution of the power of multiple electric fields, ensuring the dust removal effect, and reducing the overall running power consumption; and adjusts the rapping cycle according to the running power, thereby reducing the problems of secondary dust raising and insufficient dust removal.

Description

Technical Field

[0001] This disclosure relates to the fields of flue gas dust removal technology and electrical automatic control technology for coal-fired power plants, and in particular to a method and system for zoned variable pole spacing and pulse coordinated control of an electrostatic precipitator. Background Technology

[0002] Electrostatic precipitators (ESPs) are core equipment for flue gas dust control in coal-fired power plants, and their dust removal efficiency and operating energy consumption directly affect the power plant's environmental compliance and economic operation. With increasingly stringent emission standards for coal-fired power plants, the limit for flue gas dust emission concentration has been reduced to 10 mg / Nm³ or even lower, presenting ESPs with the dual challenges of improving efficiency and saving energy. However, existing ESPs generally adopt a design and control scheme with equal electrode spacing and a single power supply mode, which has the following prominent problems: Firstly, the flow direction of flue gas emitted from the electric field results in significant differences in dust concentration, particle size distribution, and resistivity characteristics across different areas. However, existing electrostatic precipitators use a uniform electrode spacing and the same type of cathode wire, without differentiated configuration based on the charging and dust collection requirements of each area. This leads to insufficient dust charging in the pre-charging zone and low collection efficiency of fine particles in the final fine dust collection zone.

[0003] Secondly, existing electrostatic precipitators mostly employ independent constant voltage or constant current control for their electric fields, failing to adaptively switch power supply modes based on changes in dust resistivity. When using high-resistivity coal, back corona discharge is highly likely to occur in the downstream electric field. Current technologies largely rely on turbidity meter signals for simple power adjustments, lacking precise online detection and adaptive power supply switching capabilities based on electrical characteristics and current harmonic features. When back corona discharge occurs, it reduces dust removal efficiency and wastes electrical energy.

[0004] Third, existing rapping cycles are mostly fixed settings or only subject to simple adjustments, failing to effectively link with real-time power supply and dust load. This rigid control leads to excessively frequent rapping under low loads, exacerbating secondary dust generation; and insufficient rapping under high loads, resulting in thicker dust accumulation on the plates, a drop in operating voltage, and affecting the stable operation of the equipment.

[0005] In summary, existing electrostatic precipitators have limitations in electrode configuration, power supply control, and dust removal strategies, making it difficult to simultaneously achieve high-efficiency dust removal and energy conservation under ultra-low emission requirements. Therefore, a new technical solution is urgently needed in this field to address these issues. Summary of the Invention

[0006] This disclosure provides a method and system for zoned variable pole spacing and pulse coordinated control of an electrostatic precipitator, which solves the problem that related electrostatic precipitators are difficult to balance high-efficiency dust removal and energy saving.

[0007] Based on the above problems, in a first aspect, the present disclosure provides a method for zoned variable pole spacing and pulse coordinated control of an electrostatic precipitator, comprising: Obtain the partition configuration information of the electrostatic precipitator; wherein the electrostatic precipitator is divided into multiple functional partitions along the flue gas flow direction, each functional partition includes at least one electric field, and different functional partitions adopt different electrode spacing and cathode wire configurations; Based on the partition configuration information, a corresponding power supply mode is matched to the electric field corresponding to each functional partition so that different functional partitions can operate in the corresponding power supply mode. Real-time acquisition of operating electrical data of each electric field; calculation of back corona characteristic index based on the operating electrical data; and switching of power supply mode for the corresponding electric field when the back corona characteristic index meets the preset back corona conditions. Using dust removal performance indicators and operating energy consumption indicators as joint optimization objectives, the operating power of each electric field is optimized in a coordinated manner to obtain the target power setting value of each electric field; Based on the target power setting value, the power of each electric field is controlled to adjust, and the rapping cycle of the corresponding electric field is adjusted according to the ratio of the actual operating power to the rated power of each electric field.

[0008] In conjunction with the first aspect, in one possible implementation, the electrostatic precipitator is divided into three functional zones along the flue gas flow direction: a pre-charging zone, a main dust collection zone, and a final fine collection zone. The pre-charged region adopts a first electrode spacing configuration, and the cathode wire adopts barbed wire; The main dust collection area adopts a second electrode spacing configuration, and the cathode wire adopts a star-shaped wire; The final stage fine collection area adopts a third electrode spacing configuration, and the cathode wire adopts a sawtooth wire; Wherein, the first pole spacing is smaller than the second pole spacing, and the second pole spacing is smaller than the third pole spacing; Each functional zone has guide fins arranged in the height direction of the electrode plate.

[0009] In conjunction with the first aspect, in one possible implementation, based on the partition configuration information, a corresponding power supply mode is matched for the electric field corresponding to each functional partition, including: The pre-charged zone is matched with a power frequency high voltage DC power supply mode, and the operating voltage of the pre-charged zone is set to a first voltage setting value, which is not greater than the rated voltage, so as to provide a corona current that can fully charge the dust. The main dust collection area is matched with a high-frequency power supply mode, and the operating voltage of the main dust collection area is adjusted according to the current working conditions to maintain the uniformity of the electric field according to the changes in dust load. A composite power supply mode of pulse superimposed DC is matched to the final stage fine collection zone. The DC voltage of the final stage fine collection zone is set to a second voltage setting value that is lower than the first voltage setting value, and a pulse voltage with preset pulse parameters is superimposed to improve the capture capability of fine particulate dust.

[0010] In conjunction with the first aspect, in one possible implementation, the operating electrical data includes secondary voltage and secondary current; The calculation of the back corona characteristic index based on the operating electrical data includes: Calculate the slope of the voltage-current curve based on the secondary voltage and the secondary current; If the ratio of the slope of the voltage-current curve to the reference slope under normal operating conditions is less than a preset slope threshold and the duration exceeds a preset duration, a fast Fourier transform is performed on the waveform of the secondary current to extract the target harmonic amplitude. The back corona characteristic index is calculated based on the slope of the voltage-current curve, the normal operating condition reference slope, the target harmonic amplitude, and the fundamental current amplitude.

[0011] In conjunction with the first aspect, in one possible implementation, when the anti-corona characteristic index meets a preset anti-corona condition, the power supply mode of the corresponding electric field is switched, including: If the back corona characteristic index is greater than a preset back corona threshold, it is determined that the electric field has experienced back corona. The current power supply mode of the electric field that causes back corona is switched to pulse superimposed DC power supply, and the DC voltage is reduced to a preset ratio range of the rated voltage.

[0012] In conjunction with the first aspect, in one possible implementation, the operating power of each electric field is collaboratively optimized using dust removal performance indicators and operating energy consumption indicators as joint optimization objectives to obtain the target power setpoint for each electric field, including: The objective function is to use the operating energy consumption index, which characterizes the operating power consumption of the electrostatic precipitator, as being lower than the preset total operating power consumption value, and the constraint condition is to use the dust removal performance index, which characterizes the dust concentration at the outlet of the electrostatic precipitator, as being lower than the preset emission limit value. The solution is obtained by using the particle swarm optimization algorithm. In the particle swarm optimization algorithm, the position vector of each particle represents an electric field power allocation scheme of the electrostatic precipitator, the dimension of the position vector represents the number of electric fields contained in the electrostatic precipitator, and each dimension component of the position vector represents the power setting value of the corresponding electric field. Based on the preset fitness function, the fitness value of each particle in the particle swarm is calculated. During the iterative process of the particle swarm optimization algorithm, the position vector of each particle is updated according to the fitness value until the preset iteration termination condition is met. The position vector of the particle that reaches the preset fitness value when the preset iteration termination condition is met is determined as the target power allocation scheme. The values ​​of each dimension component in the target power allocation scheme are extracted and used as the target power setting values ​​for the corresponding electric fields.

[0013] In conjunction with the first aspect, in one possible implementation, the preset fitness function is: ; in, This represents the total power consumption of the electrostatic precipitator. The penalty coefficient has a value of [value missing]. to ; The predicted dust concentration at the outlet of the electrostatic precipitator; Preset emission limits; This is the safety margin factor, with a value ranging from 0.85 to 0.95.

[0014] In conjunction with the first aspect, in one possible implementation, based on the target power setpoint, controlling each electric field to perform power regulation includes: A gradient adjustment strategy is adopted to gradually adjust the power of each electric field to approach the target power setting value; wherein the adjustment amplitude of a single adjustment does not exceed a preset percentage of the current power, and the interval between two adjacent adjustments is not less than a preset time. During the adjustment process, the actual outlet dust concentration of the electrostatic precipitator is continuously monitored. If the actual outlet dust concentration exceeds the first safety threshold, the power setting value of the previous adjustment state is returned. If the actual dust concentration at the outlet exceeds the second safety threshold, the power setting value corresponding to all electric fields will be adjusted to the rated power and an alarm will be triggered.

[0015] In conjunction with the first aspect, in one possible implementation, the rapping cycle of the corresponding electric field is adjusted according to the ratio of the actual operating power to the rated power of each electric field, including: If the ratio is less than the first ratio threshold, the vibration cycle is adjusted to a first multiple of the preset reference vibration cycle. If the ratio is not less than the first ratio threshold and not greater than the second ratio threshold, the vibration cycle is adjusted to a preset reference vibration cycle. If the ratio is greater than the second ratio threshold, the vibration cycle is adjusted to a second multiple of the preset reference vibration cycle. Monitor the secondary voltage recovery rate of the electric field after each rapping. If the secondary voltage recovery rate is less than a preset recovery rate threshold, adjust the rapping cycle to a third multiple of the preset reference rapping cycle.

[0016] Secondly, this disclosure provides a zoned variable pole gap and pulse coordinated control system for an electrostatic precipitator, comprising: The acquisition module is used to acquire the partition configuration information of the electrostatic precipitator; wherein the electrostatic precipitator is divided into multiple functional partitions along the flue gas flow direction, each functional partition includes at least one electric field, and different functional partitions adopt different electrode spacing and cathode wire configurations; The matching module is used to match the corresponding power supply mode for the electric field of each functional partition based on the partition configuration information, so that different functional partitions can operate in the corresponding power supply mode. The switching module is used to collect the operating electrical data of each electric field in real time, calculate the back corona characteristic index based on the operating electrical data, and switch the power supply mode of the corresponding electric field when the back corona characteristic index meets the preset back corona conditions. The optimization module is used to coordinately optimize the operating power of each electric field with dust removal performance index and operating energy consumption index as joint optimization objectives, so as to obtain the target power set value of each electric field. The adjustment module is used to control the power adjustment of each electric field based on the target power setting value, and to adjust the rapping cycle of the corresponding electric field according to the ratio of the actual operating power to the rated power of each electric field.

[0017] The beneficial effects of the embodiments disclosed herein include: This disclosure provides a method and system for zoned variable electrode spacing and pulse coordinated control of an electrostatic precipitator. The method includes: acquiring zoned configuration information of the electrostatic precipitator; wherein the electrostatic precipitator is divided into multiple functional zones along the flue gas flow direction, each functional zone including at least one electric field, and different functional zones using different electrode spacing and cathode wire configurations; based on the zoned configuration information, matching corresponding power supply modes for the electric fields corresponding to each functional zone, so that different functional zones operate under corresponding power supply modes; real-time acquisition of operating electrical data of each electric field, calculating the back corona characteristic index based on the operating electrical data, and switching the power supply mode of the corresponding electric field when the back corona characteristic index meets preset back corona conditions; coordinating the optimization of the operating power of each electric field with dust removal performance indicators and operating energy consumption indicators as joint optimization targets, and obtaining target power set values ​​for each electric field; based on the target power set values, controlling each electric field to perform power adjustment, and adjusting the rapping cycle of the corresponding electric field according to the ratio of the actual operating power to the rated power of each electric field. This disclosure improves the dust removal efficiency and reduces energy consumption of different zones under different flue gas conditions by configuring different electrode spacings and cathode wires for different zones and matching them with corresponding power supply modes; it calculates the back corona characteristic index based on operating electrical data and switches the power supply mode when the conditions are met to suppress the back corona phenomenon and maintain stable operation of the electric field; and it achieves reasonable power allocation of multiple electric fields by synergistically optimizing dust removal performance indicators and operating energy consumption indicators, which can reduce overall operating power consumption while ensuring dust removal effect; and it adjusts the rapping cycle of the corresponding electric field according to the operating power to match the rapping cleaning frequency with the electric field operating state, reducing secondary dust and insufficient cleaning problems. Attached Figure Description

[0018] Figure 1 A schematic flowchart illustrating a method for zoned variable pole pitch and pulse coordinated control of an electrostatic precipitator provided in this embodiment of the present disclosure; Figure 2 This is a schematic diagram of the functional partitioning provided in the embodiments of this disclosure; Figure 3 This is a schematic diagram of the structure of a zoned variable pole pitch and pulse coordinated control system for an electrostatic precipitator provided in an embodiment of this disclosure. Detailed Implementation

[0019] This disclosure provides a method and system for zoned variable pole spacing and pulse coordinated control of an electrostatic precipitator. Preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure. Furthermore, the embodiments and features described in this application can be combined with each other unless otherwise specified.

[0020] This disclosure provides a method for zoned variable pole pitch and pulse coordinated control of an electrostatic precipitator, such as... Figure 1 As shown, it can be implemented as follows: S101. Obtain the partition configuration information of the electrostatic precipitator; The electrostatic precipitator is divided into multiple functional zones along the flue gas flow direction. Each functional zone includes at least one electric field, and different functional zones use different electrode spacing and cathode wire configurations. S102. Based on the partition configuration information, match the corresponding power supply mode for the electric field corresponding to each functional partition, so that different functional partitions can operate in the corresponding power supply mode. S103. Real-time acquisition of the operating electrical data of each electric field, calculation of the back corona characteristic index based on the operating electrical data, and switching of the power supply mode for the corresponding electric field when the back corona characteristic index meets the preset back corona conditions. S104. Using dust removal performance indicators and operating energy consumption indicators as joint optimization objectives, the operating power of each electric field is optimized in a coordinated manner to obtain the target power setting value of each electric field. S105. Based on the target power setting value, control each electric field to perform power adjustment, and adjust the rapping cycle of the corresponding electric field according to the ratio of the actual operating power to the rated power of each electric field.

[0021] In this embodiment of the present disclosure, the electrostatic precipitator can be installed at the flue gas emission outlet of a coal-fired power plant. Its principle is to use a high-voltage electric field to charge the dust in the flue gas, and under the action of the electric field force, the charged dust is deposited, thereby separating solid particulate matter in the flue gas.

[0022] Electrostatic precipitators (ESPs) can be divided into functional zones along the flue gas flow direction, including a pre-charging zone, a main dust collection zone, and a final fine collection zone. Each functional zone can be equipped with multiple sets of electrodes, each corresponding to a specific cathode wire. During operation, the cathode wires can discharge, forming an electric field with the corresponding electrode. This electric field collects dust from the flue gas at the electrode. The pre-charging zone ensures that the dust entering the ESP is fully charged; the main dust collection zone handles the primary dust collection task; and the final fine collection zone captures fine particulate matter. Guide fins are installed along the height of the electrode in each zone to improve the flow field distribution of the flue gas between the electrodes and reduce secondary dust re-entrainment caused by airflow scouring.

[0023] Furthermore, different power supply modes can be set for each functional zone according to its different functions within the electrostatic precipitator, in order to respond to the functions of each zone. The dust removal function of different functional zones determines their different requirements for electric field strength and power supply characteristics. For example, the pre-charging zone requires a stronger corona discharge to fully charge high-concentration dust, so a higher operating voltage can be provided for the pre-charging zone; the main dust collection zone undertakes the main dust collection task and requires the power supply to have responsiveness and regulation capabilities, so an adjustable voltage power supply mode can be adopted; the final fine collection zone mainly targets fine particulate dust, so a pulse signal superimposed DC power supply mode can be adopted, superimposing pulses on the DC voltage to improve charging efficiency and avoid back corona phenomenon.

[0024] Back corona discharge refers to the localized breakdown discharge of dust layers deposited on the plates of an electrostatic precipitator, generating ionization discharge with the opposite polarity to the corona discharge. This discharge counteracts the dust removal electric field, leading to a decrease in dust removal efficiency. By evaluating specific data in the operating electrical data, a back corona characteristic index can be obtained to assess the severity of back corona discharge. When the back corona characteristic index exceeds a preset condition, back corona discharge can be identified, and the power supply mode of the electric field can be adjusted to suppress its development and restore the dust removal performance of the electric field.

[0025] During operation, it is also necessary to ensure that dust removal performance and power consumption remain within the limits after power supply mode switching. Based on preset dust removal performance indicators and operating energy consumption indicators, an optimization model can be used to determine the target power setting value that each electric field needs to achieve. Then, based on the target power setting value, the power of each electric field is adjusted, and the outlet dust concentration is continuously monitored during the adjustment process to prevent sudden power changes from causing emissions to exceed the standard.

[0026] Rapping is a process for cleaning dust deposited on the electrode plates. The dust load of each electric field can be determined by the ratio of actual operating power to rated power in the electrical data. The time interval between two consecutive rapping actions (i.e., the rapping cycle) can be adjusted according to the dust load. When the load is low, the rapping cycle can be extended to reduce secondary dust generation and energy consumption of the rapping system caused by frequent rapping; when the load is high, the rapping cycle can be shortened to prevent excessive dust accumulation on the electrode plates.

[0027] In summary, this disclosure improves the dust removal efficiency and reduces energy consumption of each zone under different flue gas conditions by configuring different electrode spacings and cathode wires for different zones and matching corresponding power supply modes; it calculates the back corona characteristic index based on operating electrical data and switches the power supply mode when conditions are met to suppress the back corona phenomenon and maintain stable operation of the electric field; and it achieves reasonable power allocation of multiple electric fields by synergistically optimizing dust removal performance indicators and operating energy consumption indicators, thereby reducing overall operating power consumption while ensuring dust removal effect; and it adjusts the rapping cycle of the corresponding electric field according to the operating power to match the rapping cleaning frequency with the electric field operating state, reducing secondary dust generation and insufficient cleaning problems.

[0028] In another embodiment provided in this disclosure, the electrostatic precipitator is divided into three functional zones along the flue gas flow direction: a pre-charge zone, a main dust collection zone, and a final fine collection zone. The pre-charged region adopts a first electrode spacing configuration, and the cathode wire adopts barbed wire; The main dust collection area adopts a second electrode spacing configuration, and the cathode wire adopts a star-shaped wire; The final stage fine collection area adopts a third electrode spacing configuration, and the cathode wire adopts a sawtooth wire; Wherein, the first pole spacing is smaller than the second pole spacing, and the second pole spacing is smaller than the third pole spacing; Each functional zone has guide fins arranged in the height direction of the electrode plate.

[0029] In this embodiment of the disclosure, such as Figure 2 As shown, the electrostatic precipitator can be divided into three functional zones along the flue gas flow direction (i.e., from the flue gas generation side to the flue gas emission side): the pre-charging zone, the main dust collection zone, and the final fine collection zone.

[0030] The pre-charging zone is located at the flue gas inlet and its main function is to initially charge the high-concentration dust particles that have just entered the electrostatic precipitator. The pre-charging zone adopts a first-level electrode spacing configuration. In one possible implementation, the electrode spacing in the pre-charging zone is 300 to 350 mm. In this functional area, the cathode wires corresponding to the electrode plates are barbed wires with sharp protrusions on their surfaces to provide a larger corona current, thereby ensuring that the high-concentration dust particles can be charged quickly and fully.

[0031] The main dust collection zone is located after the pre-charging zone and undertakes the main dust collection task of the electrostatic precipitator. The main dust collection zone adopts a second electrode spacing configuration. In one possible embodiment, the electrode spacing in the main dust collection zone is 400 to 450 mm; in this functional zone, the cathode wires corresponding to the electrode plates adopt star-shaped wires with a star-shaped cross-section to provide a stable and uniformly distributed electric field, thereby capturing most of the charged dust.

[0032] The final stage of the fine collection zone is located at the end of the flue gas flow direction and is mainly used to capture residual fine particulate matter in the flue gas. The final stage of the fine collection zone adopts a third electrode spacing configuration. In one possible embodiment, the electrode spacing between the electrodes in the final stage of the fine collection zone is 500 to 600 mm; in this functional zone, the cathode wire adopts a serrated edge to maintain a low electric field strength and avoid back corona phenomenon caused by the deposition of high resistivity dust on the electrode plate.

[0033] The guide fins are metal flow-guiding structures installed on the surface of the electrode plates to improve the flow field distribution of flue gas between the plates. In one possible implementation, the guide fins can be made of stainless steel, with a thickness of 1.5 to 2.5 mm, a length of one-third to one-half the distance between the electrode plates, and a projected width of 15 to 25 mm along the flue gas flow direction. The guide fins are welded to the electrode plates, with a weld length of not less than 80% of the fin length to ensure structural strength under flue gas scouring. The included angle between the guide fins and the electrode plates is set to 15 to 25 degrees, and 3 to 5 groups are evenly arranged along the height direction of the electrode plates. The structure of the fins guides the flue gas to flow uniformly between the electrode plates, reducing the scouring of the already collected dust layer on the electrode plate surface by excessively high local airflow velocities, thereby reducing secondary dust generation and improving the overall dust removal efficiency of the electrostatic precipitator.

[0034] In another embodiment provided in this disclosure, the step S102 above, "matching the corresponding power supply mode to the electric field corresponding to each functional partition based on the partition configuration information," can be implemented as follows: S1021. Match the pre-charged zone with the power frequency high voltage DC power supply mode, and set the operating voltage of the pre-charged zone to a first voltage setting value, wherein the first voltage setting value is not greater than the rated voltage, so as to provide a corona current that fully charges the dust. S1022. Match the high-frequency power supply mode to the main dust collection area, and adjust the operating voltage of the main dust collection area according to the current working conditions to maintain the uniformity of the electric field according to the changes in dust load. S1023. To match the final stage fine collection zone with a composite power supply mode of pulse superimposed DC, the DC voltage of the final stage fine collection zone is set to a second voltage setting value that is lower than the first voltage setting value, and a pulse voltage with preset pulse parameters is superimposed to improve the capture capability of fine particulate dust.

[0035] In this embodiment, the power frequency high-voltage DC power supply mode refers to a power supply method that boosts the power frequency AC input from the grid and converts it into DC output, thereby providing a stable and continuous DC high voltage. The first voltage setting value can be set to a value not exceeding the rated voltage of the electrostatic precipitator; for example, it can be set to 80% to 95% of the rated voltage. The pre-charging zone is located at the flue gas inlet, where the dust concentration is highest, therefore a large corona current is required to fully charge the dust particles.

[0036] High-frequency power supply mode refers to a power supply method that converts industrial frequency AC power into high-frequency AC power, and then outputs DC power through voltage boosting and rectification. The main dust collection area undertakes the main dust collection task, and the dust concentration and load in the flue gas will fluctuate with operating conditions. The operating voltage of the main dust collection area can be adjusted by controlling the high-frequency power supply based on real-time collected flue gas flow rate, dust concentration, and other current operating parameters.

[0037] The pulsed DC superimposed composite power supply mode refers to a power supply method that periodically superimposes pulsed voltages onto a continuously output base DC voltage. As an example, the second voltage setting can be set to 40% to 60% of the rated voltage, lower than the first voltage setting. The final stage fine collection zone mainly handles low-concentration fine particles. Lowering the base DC voltage reduces the electric field strength on the electrode surface, suppressing the back corona phenomenon caused by dust accumulation. The superimposed pulsed voltage has preset pulse parameters: a peak pulse voltage 2.5 to 3.5 times the base DC voltage, a pulse width of 50 to 150 microseconds, and a pulse repetition frequency of 50 to 200 Hz. The pulse can generate a high-intensity electric field in a short time, improving the charging efficiency and capture capability of fine dust particles. Simultaneously, due to the narrow pulse width and short energy input time, excessive dust accumulation is prevented, thus improving fine particle capture efficiency while avoiding back corona.

[0038] In yet another embodiment provided in this disclosure, the operating electrical data includes secondary voltage and secondary current; The step S103 above, "calculating the back corona characteristic index based on the operating electrical data," can be implemented as follows: S1031A. Based on the secondary voltage and the secondary current, calculate the slope of the voltage-current curve; S1032A: When the ratio of the slope of the voltage-current curve to the reference slope under normal operating conditions is less than a preset slope threshold and the duration exceeds a preset duration, a fast Fourier transform is performed on the waveform of the secondary current to extract the target harmonic amplitude. S1033A: Calculate the back corona characteristic index based on the slope of the voltage-current curve, the normal operating condition reference slope, the target harmonic amplitude, and the fundamental current amplitude.

[0039] In this embodiment of the disclosure, the operating electrical data may include secondary voltage and secondary current. Secondary voltage and secondary current refer to the actual operating voltage and operating current output by the power supply equipment (e.g., transformers and rectifiers) of the electrostatic precipitator to the electric field.

[0040] During the operation of the electrostatic precipitator, the secondary voltage of each electric field can be collected in real time. and the corresponding secondary current This allows us to obtain the slope of the voltage-current curve. The slope reflects the change in conductivity within the electric field. It should be noted that since the back corona phenomenon mainly occurs in the main dust collection zone and the final fine collection zone, only the operating electrical data of each electric field in the main dust collection zone and the final fine collection zone need to be collected.

[0041] Furthermore, when back corona occurs within the electric field, the dust layer on the plates undergoes localized breakdown, generating charges of opposite polarity. These reverse charges neutralize part of the corona, suppressing the growth of the corona current at the same voltage, manifested as a decrease in the slope of the voltage-current curve. When the ratio of the calculated slope to the reference slope under normal operating conditions is less than a preset slope threshold, and this state lasts for more than a preset duration, it can be preliminarily determined that a back corona phenomenon may exist in the electric field. In one possible implementation, when Furthermore, if the duration exceeds 60 seconds, it can be preliminarily determined that the electric field may exhibit a back corona phenomenon. The baseline slope is set at 0.5, with a preset slope threshold of 0.5 and a preset duration of 60 seconds.

[0042] To further confirm the presence of back corona discharge in the electric field, a Fast Fourier Transform (FFT) can be performed on the time-domain waveform of the acquired secondary current to analyze the various frequency components of the signal. Since back corona discharge is a nonlinear, localized breakdown discharge, it distorts the secondary current waveform, generating additional higher harmonics in the frequency domain. Therefore, the FFT can be used to extract the target harmonic amplitudes that characterize the back corona discharge. For example, the third harmonic amplitude can be extracted. and the amplitude of the 5th harmonic .

[0043] The degree of back corona occurrence can then be assessed using the back corona characteristic index. The back corona characteristic index can be calculated using the following formula (1).

[0044] (1) in, This represents the amplitude of the fundamental current. It is the anti-corona characteristic index.

[0045] In another embodiment provided in this disclosure, step S103 above, "when the anti-corona characteristic index meets the preset anti-corona condition, the power supply mode of the corresponding electric field is switched", can be implemented as follows: S1031B: If the anti-corona characteristic index is greater than the preset anti-corona threshold, it is determined that the electric field has experienced anti-corona. S1032B: Switch the current power supply mode of the electric field that causes back corona to pulse superimposed DC power supply, and reduce the DC voltage to a preset ratio range of the rated voltage.

[0046] In this embodiment, the preset back corona threshold is a predetermined critical judgment value. When the calculated back corona characteristic index exceeds the preset back corona threshold... At that time, that is This indicates that the dust layer on the plates inside the electric field has generated charges with opposite polarity to the corona polarity, resulting in suppressed corona current and distorted current waveform. As an example, The value can range from 30 to 50.

[0047] At this point, it can be clearly determined that a back corona phenomenon has occurred in the specific electric field, triggering a subsequent power supply mode switch. After switching to pulse-superimposed DC power supply, the base DC voltage can be reduced to a preset percentage range of the rated voltage. In one possible implementation, the base DC voltage can be reduced to 40%–55% of the rated voltage. Reducing the base DC voltage weakens the electric field strength on the electrode surface, reduces the charge accumulation rate of the dust layer, and thus suppresses electric field distortion within the dust layer, thereby suppressing the back corona phenomenon. Simultaneously, the superimposed high-voltage narrow pulse can generate a high concentration of charge in a short time, ensuring that even at a lower base DC voltage, the dust particles in the flue gas can still acquire sufficient charge to maintain the dust collection efficiency of the electrostatic precipitator.

[0048] In another embodiment provided in this disclosure, the step S104 above, "using dust removal performance indicators and operating energy consumption indicators as joint optimization objectives, collaboratively optimizing the operating power of each electric field to obtain the target power setting value of each electric field," can be implemented as follows: S1041. The objective function is to use the operating energy consumption index, which characterizes the operating power consumption of the electrostatic precipitator, as being lower than the preset total operating power consumption value, and the constraint condition is to use the dust removal performance index, which characterizes the dust concentration at the outlet of the electrostatic precipitator, as being lower than the preset emission limit value. The solution is obtained by using the particle swarm optimization algorithm. In the particle swarm optimization algorithm, the position vector of each particle represents an electric field power allocation scheme of the electrostatic precipitator, the dimension of the position vector represents the number of electric fields contained in the electrostatic precipitator, and each dimension component of the position vector represents the power setting value of the corresponding electric field. S1042. Based on the preset fitness function, calculate the fitness value of each particle in the particle swarm. S1043. During the iteration process of the particle swarm optimization algorithm, the position vector of each particle is updated according to the fitness value until the preset iteration termination condition is met. S1044. The position vector of the particle that reaches the preset fitness value when the preset iteration termination condition is met is determined as the target power allocation scheme. S1045. Extract the values ​​of each dimension component in the target power allocation scheme and use them as the target power setting values ​​for the corresponding electric fields.

[0049] In this embodiment, the particle swarm optimization algorithm is a global optimization algorithm based on swarm intelligence, which finds the optimal solution by simulating the collaborative search behavior of individuals in a group. In this algorithm, each particle represents a potential solution; for the purposes of this disclosure, its position vector represents an electric field power allocation scheme for the electrostatic precipitator. The dimension of the position vector represents the number of electric fields contained in the electrostatic precipitator; for example, if the electrostatic precipitator contains four electric fields, then the position vector is four-dimensional. Each dimension component in the position vector represents the power setting value of the corresponding electric field.

[0050] In the particle swarm optimization algorithm, the objective function defines the optimization direction as minimizing the sum of the powers of all electric fields, i.e., the total operating power consumption. The constraints define that operating the dust collector using the optimized power allocation scheme will not cause the outlet dust concentration to exceed the prescribed preset emission limit.

[0051] The preset fitness function is a mathematical function used to evaluate the merits of the power allocation scheme represented by each particle. The fitness function can employ a penalty function mechanism to comprehensively calculate the objective function and constraints. When the calculated outlet dust concentration of a scheme represented by a particle exceeds the preset emission limit, the fitness function will impose a penalty, worsening its fitness value. When the constraints are met, the fitness value is mainly determined by the total operating power consumption; the lower the total power consumption, the better the fitness value.

[0052] During the execution of the Particle Swarm Optimization (PSO) algorithm, each particle adjusts its search speed and updates its position vector based on its own historical best position and the global historical best position of the entire particle swarm, thereby moving towards a better solution space. Each repetition of the search and update process constitutes one iteration. The preset iteration termination condition can be reaching a set maximum number of iterations, or the change in the global optimal fitness value over multiple consecutive iterations being less than a preset convergence threshold. When either of these conditions is met, the algorithm stops iterating.

[0053] The preset fitness value refers to the optimal fitness value obtained after the algorithm converges after the termination condition is met. The position vector corresponding to the particle at this value represents the electric field power allocation scheme that, among all the schemes in the particle swarm optimization algorithm, satisfies the constraint that the outlet dust concentration is lower than the preset emission limit while minimizing the total operating power consumption.

[0054] The determined target power allocation scheme can then be analyzed, and the specific values ​​of each component can be extracted sequentially according to the dimensions. These values ​​correspond to the target power settings of each electric field in the electrostatic precipitator. These target power settings are then sent to the power supply corresponding to each electric field, controlling its output voltage and current to adjust, thereby achieving coordinated optimization control of the operating power of each electric field.

[0055] In another embodiment provided in this disclosure, the preset fitness function is: ; in, This represents the total power consumption of the electrostatic precipitator. The penalty coefficient has a value of [value missing]. to ; The predicted dust concentration at the outlet of the electrostatic precipitator; Preset emission limits; This is the safety margin factor, with a value ranging from 0.85 to 0.95.

[0056] In this embodiment of the disclosure, the expression for the preset fitness function is: .

[0057] in, This represents the fitness value. The total power consumption of the electrostatic precipitator is the sum of the electric field power settings represented by the current particle's position vector. The predicted dust concentration at the outlet of the electrostatic precipitator can be calculated using the modified Deutsch equation.

[0058] The formula for calculating the modified Deutsch equation is as follows: .in, The dust removal efficiency of the i-th electric field represents the proportion of dust that can be captured by the electric field to the total amount of dust entering the electric field. The dust collection area of ​​the i-th electric field is determined by the geometric dimensions of the plates of that electric field. is the flue gas flow rate, and is the volume of flue gas passing through the electric field per unit time; It is a natural exponential function; The effective driving velocity of the i-th electric field represents the speed at which the dust moves toward the electrode plate.

[0059] The corrected formula is .in, Let be the reference driving speed of the i-th electric field, representing the basic driving capability of the i-th electric field under rated operating conditions under standard operating conditions; Let be the rated power of the i-th electric field; This is the power setting value for the i-th electric field; The power influence index has a value of 0.3 to 0.5. The back corona influence coefficient of the i-th electric field is 0.5 to 0.8. The value is the correction coefficient for the polarity of the i-th electric field. The value can be 1.1 to 1.2 for the pre-charged zone, 1.0 for the main dust collection zone, and 0.85 to 0.95 for the final fine collection zone. Let be the back corona characteristic index of the i-th electric field.

[0060] In another embodiment provided in this disclosure, the step S105 above, "controlling each electric field to perform power adjustment based on the target power setting value," can be implemented as follows: S1051A: A gradient adjustment strategy is adopted to gradually adjust the power of each electric field to approach the target power setting value; wherein, the single adjustment amplitude does not exceed a preset percentage of the current power, and the interval between two adjacent adjustments is not less than a preset time. S1052A: During the adjustment process, continuously monitor the actual outlet dust concentration of the electrostatic precipitator. If the actual outlet dust concentration exceeds the first safety threshold, return to the power setting value of the previous adjustment state. S1053A: If the actual outlet dust concentration exceeds the second safety threshold, adjust the power setting value of all electric fields to the rated power and trigger an alarm.

[0061] In this embodiment of the disclosure, the gradient adjustment strategy refers to dividing the difference between the target power setting and the current power of each electric field into multiple smaller adjustment steps, and issuing adjustment commands sequentially to avoid the power change from impacting the electric field state inside the electrostatic precipitator.

[0062] Specifically, a single adjustment can not exceed 10% of the current power, and the interval between two adjacent adjustments should be no less than 30 seconds. During the adjustment process, the actual outlet dust concentration of the electrostatic precipitator can be continuously monitored. If the concentration exceeds... If the first safety threshold is reached, the electric field power can be reverted to the setting in the previous adjustment state. When the actual outlet dust concentration exceeds the first safety threshold, it indicates that the current gradient adjustment is causing a worsening trend in emission concentration, and the power adjustment scheme needs to be recalculated.

[0063] If the concentration exceeds (i.e., the second safety threshold) indicates that the emission standards are seriously exceeded. Priority should be given to ensuring that the emission standards are met. The power optimization target can be abandoned, and the power of the entire electric field can be changed to the rated power to restore the dust removal efficiency.

[0064] Simultaneously, it can trigger alarm information, sending alerts to staff via sound and light or push notifications to indicate that an emission exceeding standard event has occurred. Staff can then use this information to investigate the cause of the power optimization anomaly.

[0065] Furthermore, the gradient-based adjustment strategy can also include an online model correction step. Since the operating environment of electrostatic precipitators varies with factors such as coal type, electrode plate ash accumulation, and equipment aging, using fixed model parameters will lead to power optimization results that deviate from the actual physical characteristics of the electrostatic precipitator. To address this issue, the parameters of the modified Deutsch equation in the particle swarm optimization algorithm can be adjusted every 7 days using the operating data from the most recent 90 days. , and Perform least squares fitting correction.

[0066] The least squares fitting method can minimize the error between the predicted and measured values, thereby solving for the target value. , and The parameter combination, after least squares fitting correction, can control the error between the predicted and measured values ​​of the outlet dust concentration, thereby improving... Credibility.

[0067] In another embodiment provided in this disclosure, step S105 above, "adjusting the rapping cycle of the corresponding electric field according to the ratio of the actual operating power to the rated power of each electric field," can be implemented as follows: S1051B: When the ratio is less than the first ratio threshold, the vibration cycle is adjusted to a first multiple range of the preset reference vibration cycle. S1052B: When the ratio is not less than the first ratio threshold and not greater than the second ratio threshold, the vibration cycle is adjusted to a preset reference vibration cycle. S1053B: When the ratio is greater than the second ratio threshold, the vibration cycle is adjusted to a second multiple of the preset reference vibration cycle. S1054B: Monitor the secondary voltage recovery rate of the electric field after each rapping. If the secondary voltage recovery rate is less than a preset recovery rate threshold, adjust the rapping cycle to a third multiple of the preset reference rapping cycle.

[0068] In this embodiment of the disclosure, when the ratio of actual operating power to rated power is... When the ratio is less than 0.4 (i.e., the first ratio threshold), the rapping cycle of the electrode and cathode wire against the electric field can be reduced. It can be set as the reference vibration cycle. The vibration cycle is extended by 1.5 to 2.0 times (i.e., the first multiple range) to allow the electrode plate more time to accumulate ash. Vibration is then performed only after the ash layer reaches a certain thickness, which can improve the ash removal efficiency and reduce unnecessary vibrations.

[0069] when When the second ratio threshold is reached, the rapping cycle can be adjusted. Set as the reference vibration cycle Maintaining the baseline cycle ensures stable and economical operation of the dust collector.

[0070] when At that time, the vibration cycle can be adjusted. Set as the reference vibration cycle The cleaning frequency should be increased to 0.5 to 0.7 times (i.e., the second multiple range) to accelerate the cleaning frequency and prevent excessive accumulation of ash layer.

[0071] In addition, the secondary voltage recovery rate of the electric field after each rapping can be monitored. Secondary voltage recovery rate The calculation formula is: .in, This is the secondary voltage value before vibration. This is the secondary voltage value after the vibration is completed. This represents the rated secondary voltage value of the electric field. This formula can be used to quantify the recovery capability of the secondary voltage of the electric field after rapping. A value less than 0.6 (i.e., the preset recovery rate threshold) indicates that the secondary voltage failed to recover to a normal level after rapping, suggesting that a thicker dust layer may still exist, resulting in insufficient dust removal through rapping. In this case, the rapping cycle can be adjusted. Further shorten to the baseline rapping cycle The dust accumulation on the electrode plates is forcibly removed by 0.4 to 0.6 times (i.e., the third multiple range) through higher frequency vibration, thereby improving the conductivity of the electrode plate surface.

[0072] This disclosure also provides a zoned variable pole gap and pulse coordinated control system for an electrostatic precipitator, such as Figure 3 As shown, it includes: The acquisition module 301 is used to acquire the partition configuration information of the electrostatic precipitator; wherein, the electrostatic precipitator is divided into multiple functional partitions along the flue gas flow direction, each functional partition includes at least one electric field, and different functional partitions adopt different electrode spacing and cathode wire configurations; Matching module 302 is used to match the corresponding power supply mode for the electric field corresponding to each functional partition based on the partition configuration information, so that different functional partitions can operate in the corresponding power supply mode; The switching module 303 is used to collect the operating electrical data of each electric field in real time, calculate the back corona characteristic index based on the operating electrical data, and switch the power supply mode of the corresponding electric field when the back corona characteristic index meets the preset back corona conditions. The optimization module 304 is used to coordinately optimize the operating power of each electric field with dust removal performance index and operating energy consumption index as joint optimization objectives, so as to obtain the target power setting value of each electric field. The adjustment module 305 is used to control the power adjustment of each electric field based on the target power setting value, and to adjust the rapping cycle of the corresponding electric field according to the ratio of the actual operating power to the rated power of each electric field.

[0073] In another embodiment provided in this disclosure, the matching module 302 is used to match the pre-charged zone with a power frequency high-voltage DC power supply mode, setting the operating voltage of the pre-charged zone to a first voltage setting value, which is not greater than the rated voltage, so as to provide a corona current to fully charge the dust; to match the main dust collection zone with a high-frequency power supply mode, adjusting the operating voltage of the main dust collection zone according to the current working conditions, so as to maintain the uniformity of the electric field according to the change of dust load; and to match the final fine collection zone with a composite power supply mode of pulse superimposed DC, setting the DC voltage of the final fine collection zone to a second voltage setting value lower than the first voltage setting value, and superimposing a pulse voltage with preset pulse parameters to improve the capture capability of fine particulate dust.

[0074] In another embodiment provided in this disclosure, the switching module 303 is used to calculate the slope of the voltage-current curve based on the secondary voltage and the secondary current; when the ratio of the voltage-current curve slope to the reference slope under normal operating conditions is less than a preset slope threshold and the duration exceeds a preset duration, the waveform of the secondary current is subjected to a fast Fourier transform to extract the target harmonic amplitude; and the back corona characteristic index is calculated based on the voltage-current curve slope, the reference slope under normal operating conditions, the target harmonic amplitude, and the fundamental current amplitude.

[0075] In another embodiment provided in this disclosure, the switching module 303 is used to determine that the electric field has experienced back corona when the back corona characteristic index is greater than a preset back corona threshold; to switch the current power supply mode of the electric field experiencing back corona to pulse superimposed DC power supply; and to reduce the DC voltage to a preset ratio range of the rated voltage.

[0076] In another embodiment provided in this disclosure, the optimization module 304 is used to solve the problem using a particle swarm optimization algorithm with the objective function being an operating energy consumption index (characterizing the operating power consumption of the electrostatic precipitator) lower than a preset total operating power consumption value, and the constraint condition being a dust removal performance index (characterizing the dust concentration at the outlet of the electrostatic precipitator) lower than a preset emission limit value. In the particle swarm optimization algorithm, the position vector of each particle represents an electric field power allocation scheme for the electrostatic precipitator, the dimension of the position vector represents the number of electric fields contained in the electrostatic precipitator, and each dimension component of the position vector represents the power setting value of the corresponding electric field. Based on a preset fitness function, the fitness value of each particle in the particle swarm is calculated. During the iteration process of the particle swarm optimization algorithm, the position vector of each particle is updated according to the fitness value until a preset iteration termination condition is met. The position vector of the particle that reaches the preset fitness value when the preset iteration termination condition is met is determined as the target power allocation scheme. The values ​​of each dimension component in the target power allocation scheme are extracted and used as the target power setting values ​​of the corresponding electric fields.

[0077] In another embodiment provided in this disclosure, the adjustment module 305 is used to employ a gradient adjustment strategy to gradually adjust the power of each electric field to approach the target power setting value; wherein, the single adjustment amplitude does not exceed a preset percentage of the current power, and the interval between two adjacent adjustments is not less than a preset time; during the adjustment process, the actual outlet dust concentration of the electrostatic precipitator is continuously monitored, and if the actual outlet dust concentration exceeds a first safety threshold, the power setting value of the previous adjustment state is returned; if the actual outlet dust concentration exceeds a second safety threshold, the power setting values ​​corresponding to all electric fields are adjusted to the rated power and an alarm is triggered.

[0078] In another embodiment provided in this disclosure, the adjustment module 305 is configured to: adjust the rapping cycle to a first multiple of a preset reference rapping cycle when the ratio is less than a first ratio threshold; adjust the rapping cycle to a preset reference rapping cycle when the ratio is not less than the first ratio threshold and not greater than a second ratio threshold; adjust the rapping cycle to a second multiple of the preset reference rapping cycle when the ratio is greater than the second ratio threshold; monitor the secondary voltage recovery rate of the electric field after each rapping, and adjust the rapping cycle to a third multiple of the preset reference rapping cycle when the secondary voltage recovery rate is less than a preset recovery rate threshold.

[0079] The above content will be explained below with an example. Assume a 600MW coal-fired unit uses a dual-chamber, five-field electrostatic precipitator to remove dust from flue gas. This electrostatic precipitator can be re-divided into three functional zones along the flue gas flow direction: the pre-charge zone includes one electric field (first electric field), with an electrode spacing adjusted to 320mm and barbed cathode wires; the main dust collection zone includes two electric fields (second and third electric fields), with an electrode spacing of 420mm and star-shaped cathode wires; the final stage fine collection zone includes two electric fields (fourth and fifth electric fields), with an electrode spacing adjusted to 550mm and serrated cathode wires. Guide fins, made of 316L stainless steel, 2mm thick and 180mm long, are welded along the height of the anode plates in each zone. The angle between the fins and the electrode plates is 20°, and four sets are arranged at equal intervals along the height of the electrode plates.

[0080] The power supply units in the zone provide corresponding power supply modes for different functional areas. The pre-charge zone is powered by a high-voltage DC power supply (rated 72kV / 1.8A) with an operating voltage of 65kV. Each electric field in the main dust collection zone is powered by a high-frequency power supply (rated 72kV / 2.0A) with an initial operating voltage of 60kV. Each electric field in the final fine collection zone is equipped with a pulse superimposed DC composite power supply with a base DC voltage of 42kV (58% of the rated 72kV), a pulse peak voltage of 126kV (3 times the base DC voltage), a pulse width of 100μs, and a repetition frequency of 120Hz.

[0081] The system can collect secondary voltage and secondary current signals in each electric field in real time through the data acquisition unit, collect outlet dust concentration signals through the turbidity meter, and obtain data such as boiler load and flue gas temperature from the power plant DCS system. It can also record coal ash content information.

[0082] Taking the second electric field in the main dust collection area as an example, when the secondary voltage of this electric field is monitored to be 52kV and the secondary current to be 1.2A, calculate the slope of the voltage-current curve. If the set baseline slope ,but This process continues for over 60 seconds. Further FFT analysis of the secondary current waveform allows for the extraction of... , , And then calculate Preset Since RCI < 35, it is determined that no back corona occurred in the second electric field.

[0083] Taking the fourth electric field in the final stage of fine collection as an example, when the secondary voltage of this electric field is monitored to be 48kV and the secondary current to be 1.5A, calculate... , And it lasted for more than 60 seconds. Through FFT analysis, it can be extracted... , , And then calculate Although the back corona detection criteria were not triggered, the field was close to the preset back corona threshold, so an early warning marker could be set for the electric field.

[0084] During further operation of the coal-fired unit, assuming the coal ash content increases from 22% to 38%, causing the RCI of the fourth electric field to rise to 42, back corona discharge can be identified. The system can reduce the base DC voltage of this electric field to 36kV, adjust the pulse peak voltage to 108kV, the pulse width to 80μs, and the repetition frequency to 150Hz. The RCI of this electric field is then continuously monitored until it decreases below the normal RCI level (e.g., below 18).

[0085] During the operation of the dust collector, particle swarm optimization can be performed simultaneously to adjust the dust collector's power. Assuming the particle swarm algorithm has 40 particles and a maximum of 100 iterations, the inertia weight can be set to linearly decrease from 0.9 to 0.4. The final optimized result is: a pre-charge zone power of 55kW (rated 65kW), a main dust collection zone power of 80kW (rated 120kW), and a final fine collection zone power of 65kW (rated 120kW), for a total power of 200kW, a significant reduction from the rated total power of 305kW.

[0086] Then, a gradient strategy is used to perform power regulation. Taking the fifth electric field in the final stage of the dust collector as an example, the current power is 60kW, and the target power is 32kW. Each adjustment reduces the current power by 10%, or 6kW each time, and is performed every 30 seconds. After 7 rounds, the regulation is completed in about 3.5 minutes. During this process, the dust concentration at the outlet of the dust collector gradually increases from 5mg / Nm³ to 7.5mg / Nm³, but remains below the first safety threshold. .

[0087] Furthermore, the rapping cycle can be optimized, and the operating power ratio of the fifth electric field can be improved. Within the range of 0.4 to 0.8, the baseline rapping cycle can be maintained. The minutes remain unchanged.

[0088] Assume the current power of the fourth electric field is 28kW. , and maintain .

[0089] When the subsequent power of the fifth electric field drops to 22kW If the ratio is less than the first threshold, the rapping cycle can be extended to... Minutes. Monitoring secondary voltage recovery rate after vibration. ,like Then shorten the cycle to minute.

[0090] In another example, a two-chamber six-electric-field electrostatic precipitator supporting a 1000MW ultra-supercritical unit is taken as the regulation object. It is assumed that the first electric field of the electrostatic precipitator is a pre-charging zone with an electrode spacing of 300mm and adopts spiked wires; the second, third and fourth electric fields are main dust collection zones with an electrode spacing of 400mm and adopt star wires; the fifth and sixth electric fields are final-stage fine dust collection zones with an electrode spacing of 500mm and adopt sawtooth wires. The angle between the flow guide fins and the collecting plate is 15°, and 3 sets are arranged.

[0091] When the unit burns a low-ash coal type with an ash content of 15%, the total power consumption of the precipitator after collaborative optimization is 45% of the rated power, and the outlet dust concentration is 4.5mg / Nm³. When the coal type changes to a high-ash coal type with an ash content of 38%, the RCI of the fifth electric field is detected to be 46. At this time, the power supply mode can be switched. After gradient regulation, the total power consumption returns to 68% of the rated power, and the outlet dust concentration is stabilized at 8.2mg / Nm³, which meets the 10mg / Nm³ emission standard.

[0092] Through the description of the above embodiments, those skilled in the art can clearly understand that the embodiments of the present disclosure can be implemented by hardware, or by means of software plus a necessary general-purpose hardware platform. Based on such understanding, the technical solutions of the embodiments of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which may be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present disclosure.

[0093] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of a preferred embodiment, and the modules or processes in the accompanying drawings are not necessarily essential for implementing the present disclosure.

[0094] Those skilled in the art can understand that the modules in the system in the embodiments can be distributed in the system of the embodiment according to the description of the embodiment, or can be correspondingly changed to be located in one or more systems different from the present embodiment. The modules of the above embodiments may be combined into one module, or further split into a plurality of sub-modules.

[0095] The serial numbers of the above embodiments of the present disclosure are only for description, and do not represent the superiority or inferiority of the embodiments.

[0096] Obviously, those skilled in the art can make various modifications and variations to the present disclosure without departing from the spirit and scope of the present disclosure. In this way, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalent technologies, the present disclosure is also intended to cover these modifications and variations.

Claims

1. A method for zoned variable pole pitch and pulse coordinated control of an electrostatic precipitator, characterized in that, include: Obtain the partition configuration information of the electrostatic precipitator; wherein the electrostatic precipitator is divided into multiple functional partitions along the flue gas flow direction, each functional partition includes at least one electric field, and different functional partitions adopt different electrode spacing and cathode wire configurations; Based on the partition configuration information, a corresponding power supply mode is matched to the electric field corresponding to each functional partition so that different functional partitions can operate in the corresponding power supply mode. Real-time acquisition of operating electrical data of each electric field; calculation of back corona characteristic index based on the operating electrical data; and switching of power supply mode for the corresponding electric field when the back corona characteristic index meets the preset back corona conditions. Using dust removal performance indicators and operating energy consumption indicators as joint optimization objectives, the operating power of each electric field is optimized in a coordinated manner to obtain the target power setting value of each electric field; Based on the target power setting value, the power of each electric field is controlled to adjust, and the rapping cycle of the corresponding electric field is adjusted according to the ratio of the actual operating power to the rated power of each electric field.

2. The method as described in claim 1, characterized in that, The electrostatic precipitator is divided into three functional zones along the flue gas flow direction: a pre-charge zone, a main dust collection zone, and a final fine collection zone. The pre-charged region adopts a first electrode spacing configuration, and the cathode wire adopts barbed wire; The main dust collection area adopts a second electrode spacing configuration, and the cathode wire adopts a star-shaped wire; The final stage fine collection area adopts a third electrode spacing configuration, and the cathode wire adopts a sawtooth wire; Wherein, the first pole spacing is smaller than the second pole spacing, and the second pole spacing is smaller than the third pole spacing; Each functional zone has guide fins arranged in the height direction of the electrode plate.

3. The method as described in claim 2, characterized in that, Based on the partition configuration information, a corresponding power supply mode is matched for the electric field corresponding to each functional partition, including: The pre-charged zone is matched with a power frequency high voltage DC power supply mode, and the operating voltage of the pre-charged zone is set to a first voltage setting value, which is not greater than the rated voltage, so as to provide a corona current that can fully charge the dust. The main dust collection area is matched with a high-frequency power supply mode, and the operating voltage of the main dust collection area is adjusted according to the current working conditions to maintain the uniformity of the electric field according to the changes in dust load. A composite power supply mode of pulse superimposed DC is matched to the final stage fine collection zone. The DC voltage of the final stage fine collection zone is set to a second voltage setting value that is lower than the first voltage setting value, and a pulse voltage with preset pulse parameters is superimposed to improve the capture capability of fine particulate dust.

4. The method as described in claim 1, characterized in that, The operating electrical data includes secondary voltage and secondary current; The calculation of the back corona characteristic index based on the operating electrical data includes: Calculate the slope of the voltage-current curve based on the secondary voltage and the secondary current; If the ratio of the slope of the voltage-current curve to the reference slope under normal operating conditions is less than a preset slope threshold and the duration exceeds a preset duration, a fast Fourier transform is performed on the waveform of the secondary current to extract the target harmonic amplitude. The back corona characteristic index is calculated based on the slope of the voltage-current curve, the normal operating condition reference slope, the target harmonic amplitude, and the fundamental current amplitude.

5. The method as described in claim 4, characterized in that, When the anti-corona characteristic index meets the preset anti-corona condition, the power supply mode of the corresponding electric field is switched, including: If the back corona characteristic index is greater than a preset back corona threshold, it is determined that the electric field has experienced back corona. The current power supply mode of the electric field that causes back corona is switched to pulse superimposed DC power supply, and the DC voltage is reduced to a preset ratio range of the rated voltage.

6. The method as described in claim 1, characterized in that, Using dust removal performance and operating energy consumption as joint optimization objectives, the operating power of each electric field is synergistically optimized to obtain the target power setpoints for each electric field, including: The objective function is to use the operating energy consumption index, which characterizes the operating power consumption of the electrostatic precipitator, as being lower than the preset total operating power consumption value, and the constraint condition is to use the dust removal performance index, which characterizes the dust concentration at the outlet of the electrostatic precipitator, as being lower than the preset emission limit value. The solution is obtained by using the particle swarm optimization algorithm. In the particle swarm optimization algorithm, the position vector of each particle represents an electric field power allocation scheme of the electrostatic precipitator, the dimension of the position vector represents the number of electric fields contained in the electrostatic precipitator, and each dimension component of the position vector represents the power setting value of the corresponding electric field. Based on the preset fitness function, the fitness value of each particle in the particle swarm is calculated. During the iterative process of the particle swarm optimization algorithm, the position vector of each particle is updated according to the fitness value until the preset iteration termination condition is met. The position vector of the particle that reaches the preset fitness value when the preset iteration termination condition is met is determined as the target power allocation scheme. The values ​​of each dimension component in the target power allocation scheme are extracted and used as the target power setting values ​​for the corresponding electric fields.

7. The method as described in claim 6, characterized in that, The preset fitness function is: ; in, This represents the total power consumption of the electrostatic precipitator. The penalty coefficient has a value of [value missing]. to ; The predicted dust concentration at the outlet of the electrostatic precipitator; Preset emission limits; This is the safety margin factor, with a value ranging from 0.85 to 0.

95.

8. The method as described in claim 1, characterized in that, Based on the target power setpoint, control each electric field to perform power regulation, including: A gradient adjustment strategy is adopted to gradually adjust the power of each electric field to approach the target power setting value; wherein the adjustment amplitude of a single adjustment does not exceed a preset percentage of the current power, and the interval between two adjacent adjustments is not less than a preset time. During the adjustment process, the actual outlet dust concentration of the electrostatic precipitator is continuously monitored. If the actual outlet dust concentration exceeds the first safety threshold, the power setting value of the previous adjustment state is returned. If the actual dust concentration at the outlet exceeds the second safety threshold, the power setting value corresponding to all electric fields will be adjusted to the rated power and an alarm will be triggered.

9. The method as described in claim 1, characterized in that, Based on the ratio of the actual operating power to the rated power of each electric field, adjust the rapping cycle of the corresponding electric field, including: If the ratio is less than the first ratio threshold, the vibration cycle is adjusted to a first multiple of the preset reference vibration cycle. If the ratio is not less than the first ratio threshold and not greater than the second ratio threshold, the vibration cycle is adjusted to a preset reference vibration cycle. If the ratio is greater than the second ratio threshold, the vibration cycle is adjusted to a second multiple of the preset reference vibration cycle. Monitor the secondary voltage recovery rate of the electric field after each rapping. If the secondary voltage recovery rate is less than a preset recovery rate threshold, adjust the rapping cycle to a third multiple of the preset reference rapping cycle.

10. A zoned variable pole gap and pulse coordinated control system for an electrostatic precipitator, characterized in that, include: The acquisition module is used to acquire the partition configuration information of the electrostatic precipitator; wherein the electrostatic precipitator is divided into multiple functional partitions along the flue gas flow direction, each functional partition includes at least one electric field, and different functional partitions adopt different electrode spacing and cathode wire configurations; The matching module is used to match the corresponding power supply mode for the electric field of each functional partition based on the partition configuration information, so that different functional partitions can operate in the corresponding power supply mode. The switching module is used to collect the operating electrical data of each electric field in real time, calculate the back corona characteristic index based on the operating electrical data, and switch the power supply mode of the corresponding electric field when the back corona characteristic index meets the preset back corona conditions. The optimization module is used to coordinately optimize the operating power of each electric field with dust removal performance index and operating energy consumption index as joint optimization objectives, so as to obtain the target power set value of each electric field. The adjustment module is used to control the power adjustment of each electric field based on the target power setting value, and to adjust the rapping cycle of the corresponding electric field according to the ratio of the actual operating power to the rated power of each electric field.

Images