Cyclone cloth bag dust removal and three-stage spray tail gas purification system

Abstract

The application provides a cyclone cloth bag dust removal and three-stage spray tail gas purification system, and relates to the technical field of industrial tail gas purification.The cyclone cloth bag dust removal and three-stage spray tail gas purification system comprises a cyclone cloth bag pretreatment unit, a three-stage spray washing unit, a parameter acquisition unit and a control unit; the control unit identifies the non-clogging fine dispersed particle escape state according to the pretreatment tail gas volume flow, the spray inlet and outlet particulate matter concentration and the operating pressure difference, re-distributes the spray control amount to the second and third spray stages under the condition that the total spray demand is limited, and controls the out-of-phase compensation spray based on the inter-stage residence time and the phase correction amount, so that the fine dispersed particles are first treated in the intensified coagulation droplet field and then enter the terminal compensation capture droplet field. The cyclone cloth bag dust removal and three-stage spray tail gas purification system can improve the wetting, coagulation and compensation capture effect of the residual fine dispersed particles and stably reduce the rotary kiln tail gas particulate matter concentration.

Description

Technical Field

[0001] This invention relates to the field of industrial exhaust gas purification technology, specifically a cyclone bag filter dust collector and a three-stage spray exhaust gas purification system. Background Technology

[0002] Rotary kilns generate dust-laden exhaust gas during calcination, roasting, or heat treatment. This exhaust gas typically contains a significant amount of dust, smoke, and fine, dispersed particles. Existing rotary kiln exhaust gas treatment systems often employ a combination of cyclone dust collectors, bag filters, and spray purification. Large dust particles are pretreated first, and then the exhaust gas is exposed to a spray solution, causing the particulate matter in the exhaust gas to be wetted, agglomerated, and discharged with the scrubbing liquid.

[0003] However, the existing spray purification section does not adequately capture the fine dispersed particles remaining after pretreatment. The main problems are insufficient gas-liquid contact, uneven spray coverage, and fine particles escaping with the airflow, resulting in unstable purification effect of particulate matter in rotary kiln tail gas. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a cyclone bag filter dust collection and three-stage spray exhaust gas purification system. Based on the inter-stage residence time and outlet particulate matter response, the three-stage spray phase mismatch compensation control method solves the problem that residual fine dispersed particles in the rotary kiln pretreatment exhaust gas escape due to insufficient gas-liquid contact and uneven spray coverage, resulting in unstable particulate matter purification effect.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a cyclone bag filter dust collection and three-stage spray exhaust gas purification system, comprising a cyclone bag pretreatment unit, a three-stage spray washing unit, a parameter acquisition unit, and a control unit. The three-stage spray washing unit sequentially forms a first spray section, a second spray section, and a third spray section along the exhaust gas flow direction. The control unit is configured to execute the following control process:

[0006] S1. The parameter acquisition unit acquires the pre-treated exhaust gas parameters of the pre-treated exhaust gas output by the cyclone bag pre-treatment unit. The pre-treated exhaust gas is the airflow formed after the dust-laden exhaust gas of the rotary kiln is treated by the cyclone bag pre-treatment unit and carries residual fine dispersed particles. The pre-treated exhaust gas parameters include the pre-treated exhaust gas volumetric flow rate, the particulate matter concentration at the spray inlet, the particulate matter concentration at the spray outlet, and the operating pressure difference of the three-stage spray washing unit.

[0007] S2. Determine the total spray demand of the three-stage spray scrubbing unit based on the pre-treated exhaust gas volume flow rate and the particulate matter concentration at the spray inlet, and generate the initial spray control quantities for the first spray section, the second spray section, and the third spray section, so that the first spray section is used for wetting and capturing, the second spray section is used for enhanced coagulation, and the third spray section is used for end-of-pipe compensation capturing.

[0008] S3. When the particulate matter concentration at the spray outlet is higher than the target particulate matter concentration and the operating pressure difference does not exceed the pressure difference threshold, the three-stage spray washing unit is determined to be in a non-clogging fine dispersed particle escape state; in the non-clogging fine dispersed particle escape state, the control unit, under the condition that the total spray demand does not increase or the increase does not exceed a preset ratio, redistributes part of the spray control quantity of the first spray section to the second spray section and the third spray section;

[0009] S4. Determine the inter-segment residence time based on the effective gas volume between the second spray section and the third spray section and the pre-treated exhaust gas volume flow rate after operating condition correction, and determine the compensation enhanced spray trigger time of the third spray section relative to the second spray section based on the inter-segment residence time and the phase correction amount of the current control cycle.

[0010] S5. Control the second spray section to enter an enhanced spray state within the first pulse window to form an enhanced coagulation droplet field of the first droplet spectrum; and control the third spray section to enter an enhanced spray state within the second pulse window corresponding to the compensation enhanced spray trigger time to form an end-compensation trapping droplet field of the second droplet spectrum, different from the first droplet spectrum, so that the residual fine dispersed particles are first wetted and coagulated in the second spray section, and then compensated and trapped in the third spray section; wherein, the enhanced spray state is a state in which the spray control quantity of the corresponding spray section is higher than the non-zero reference spray quantity of the spray section, and the spray control quantity includes at least one of spray flow rate, spray pressure, pulse duty cycle or spray frequency; the second spray section and the third spray section are not in the enhanced spray state at the same time, and when any spray section is in the enhanced spray state, the other spray section maintains a non-zero reference spray quantity;

[0011] S6. After the second pulse window, obtain the decrease response of the particulate matter concentration at the spray outlet, and update the phase correction amount in the next control cycle according to the response offset of the decrease response relative to the preset response time. When the decrease response lags behind the preset response time, shift the compensation enhanced spray trigger time in the next control cycle backward; when the decrease response is earlier than the preset response time, shift the compensation enhanced spray trigger time in the next control cycle forward, so that the actual escaped fine dispersed particulate matter gas clouds migrate to the third spray section and enter the end compensation trapping droplet field, and obtain purified gas with a stable decrease in particulate matter concentration.

[0012] Preferably, the pretreated exhaust gas parameters further include pretreated exhaust gas temperature and pretreated exhaust gas pressure; the pretreated exhaust gas volumetric flow rate after operating condition correction is calculated based on the pretreated exhaust gas volumetric flow rate, the pretreated exhaust gas temperature and the pretreated exhaust gas pressure, and is used to characterize the actual volumetric flow rate of the pretreated exhaust gas in the three-stage spray washing unit.

[0013] Preferably, the effective gas volume between the second spray section and the third spray section is the net volume within the tower for the pretreated tail gas to circulate between the outlet section of the second spray section and the inlet section of the third spray section; the inter-section residence time is determined by the ratio of the effective gas volume to the pretreated tail gas volumetric flow rate after operating condition correction.

[0014] Preferably, the determination of the non-clogging fine dispersed particle escape state includes: when the concentration of particulate matter at the spray outlet is higher than the target particulate matter concentration for at least two consecutive sampling periods, and the operating pressure difference does not exceed the pressure difference threshold, the three-stage spray washing unit is determined to be in the non-clogging fine dispersed particle escape state.

[0015] Preferably, in the non-clogging fine dispersed particle escape state, the control unit allocates the spray control amount deducted from the first spray section to the second spray section and the third spray section; when the total spray demand increases, the increase in the total spray demand does not exceed 10% of the total spray demand before entering the non-clogging fine dispersed particle escape state.

[0016] Preferably, the first droplet spectrum and the second droplet spectrum are formed by the nozzle aperture, spray pressure and spray flow rate of the corresponding spray section, respectively. The median particle size of the first droplet spectrum is larger than the median particle size of the second droplet spectrum, and the droplet number density of the second droplet spectrum in the corresponding spray droplet field is greater than the droplet number density of the first droplet spectrum in the corresponding spray droplet field.

[0017] Preferably, the first pulse window and the second pulse window do not overlap in time; the starting time of the second pulse window is the time after the starting time of the first pulse window, which is the sum of the inter-segment dwell time and the phase correction amount.

[0018] Preferably, the decrease response is the response formed when the particulate concentration at the spray outlet decreases to a preset decrease range relative to the particulate concentration at the spray outlet when entering the non-clogging fine dispersed particle escape state, and the response offset is the time difference between the actual response time of the decrease response and the preset response time. The control unit updates the phase correction amount in the next control cycle according to the time difference.

[0019] Preferably, the third spray section includes multiple compensation spray zones distributed along the cross-section of the three-stage spray washing unit, the parameter acquisition unit includes an outlet end particulate matter detection point corresponding to each of the compensation spray zones, the control unit determines the escape channel region of fine dispersed particles based on the particulate matter concentration detected by each of the outlet end particulate matter detection points, and increases the spray control amount of the compensation spray zone corresponding to the escape channel region within the second pulse window.

[0020] Preferably, when the operating pressure difference exceeds the pressure difference threshold, the control unit stops executing the control process for the escape state of the non-clogging fine dispersed particles, and controls the second spray section and the third spray section to maintain the non-zero reference spray volume, while increasing the discharge frequency or replacement frequency of the dust-carrying washing liquid of the three-stage spray washing unit.

[0021] This invention provides a cyclone bag filter dust collection and three-stage spray exhaust gas purification system. It has the following beneficial effects:

[0022] This cyclone baghouse dust collector and three-stage spray scrubbing exhaust gas purification system pre-treats the dust-laden exhaust gas from the rotary kiln via a cyclone baghouse pretreatment unit before sending it to a three-stage spray scrubbing unit for graded wet collection. This ensures that the pre-treated exhaust gas entering the spray section primarily carries residual fine dispersed particles, reducing the interference of large dust particles on the subsequent spray scrubbing process. The three-stage spray scrubbing unit sequentially forms wetting and collection, enhanced coagulation, and end-of-pipe compensation collection processes along the exhaust gas flow direction. This allows residual fine dispersed particles to be wetted by the spray liquid first, and then coagulate and compensate for collection in the spray droplet field with different droplet spectra. This increases the contact probability between the spray liquid and the fine dispersed particles, reduces the problem of fine particles escaping with the stable airflow channel, and improves the stability of the particulate matter purification effect of the rotary kiln exhaust gas.

[0023] Furthermore, when the particulate matter concentration at the spray outlet increases but the operating differential pressure does not exceed the differential pressure threshold, this invention determines it to be a non-clogging, finely dispersed particle escape state. Under the condition that the total spray demand does not increase or its increase is limited, the spray control quantity is redistributed from the first spray section to the second and third spray sections, avoiding increased liquid consumption, increased differential pressure, or dust-laden droplet retention caused by simply increasing the overall spray volume. Simultaneously, this invention determines the compensation-enhanced spray triggering time based on the inter-segment residence time and phase correction amount between the second and third spray sections, and updates the phase correction amount for the next control cycle based on the decrease in particulate matter concentration at the spray outlet. This ensures that the end-compensation droplet trapping field of the third spray section matches the arrival time of the actual escaped finely dispersed particle gas cloud, thereby improving the dynamic trapping capability and continuous operation stability of residual finely dispersed particles in the rotary kiln pretreatment tail gas. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure and control relationship of a cyclone bag filter and three-stage spray exhaust gas purification system according to the present invention.

[0025] Figure 2 This is a flowchart illustrating the escape state determination process for non-clogging finely dispersed particles according to the present invention.

[0026] Figure 3 This is a flowchart of the phase-shift pulse compensation control based on inter-segment dwell time of the present invention;

[0027] Figure 4 This is a flowchart illustrating the collaborative trapping process of the first and second droplet spectra of the present invention.

[0028] Figure 5 This is a flowchart of the spray outlet particulate matter concentration decrease response and phase correction update process of the present invention;

[0029] Figure 6 This is a flowchart of the abnormal handling process for compensating for spray zone and pressure difference in this invention. Detailed Implementation

[0030] 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.

[0031] Example 1

[0032] like Figure 1 As shown, this embodiment of the invention provides a cyclone bag filter dust collection and three-stage spray exhaust gas purification system, including a cyclone bag pretreatment unit, a three-stage spray washing unit, a parameter acquisition unit, and a control unit. The three-stage spray washing unit sequentially forms a first spray section, a second spray section, and a third spray section along the exhaust gas flow direction. The control unit is configured to execute the following control process:

[0033] S1. The parameter acquisition unit acquires the pre-treated tail gas parameters output by the cyclone bag pre-treatment unit. The pre-treated tail gas is the airflow formed after the dust-laden tail gas of the rotary kiln is treated by the cyclone bag pre-treatment unit and carries residual fine dispersed particles. The pre-treated tail gas parameters include the pre-treated tail gas volume flow rate, the particulate matter concentration at the spray inlet, the particulate matter concentration at the spray outlet, and the operating pressure difference of the three-stage spray washing unit.

[0034] The pre-treated exhaust gas parameters also include the pre-treated exhaust gas temperature and pre-treated exhaust gas pressure; the pre-treated exhaust gas volumetric flow rate after operating condition correction is calculated based on the pre-treated exhaust gas volumetric flow rate, pre-treated exhaust gas temperature and pre-treated exhaust gas pressure, and is used to characterize the actual volumetric flow rate of the pre-treated exhaust gas in the three-stage spray scrubbing unit.

[0035] Specifically, in this embodiment, the pre-treated exhaust gas volumetric flow rate, the particulate matter concentration at the spray inlet, the particulate matter concentration at the spray outlet, and the operating pressure difference are used to characterize the inlet air load, inlet dust state, outlet purification state, and airflow resistance state of the three-stage spray scrubbing unit, respectively.

[0036] S2. Determine the total spray demand of the three-stage spray scrubbing unit based on the pre-treated exhaust gas volume flow rate and the particulate matter concentration at the spray inlet, and generate the initial spray control quantities for the first, second, and third spray sections, so that the first spray section is used for wetting and capturing, the second spray section is used for enhanced coagulation, and the third spray section is used for end-of-pipe compensation capturing.

[0037] Specifically, in this embodiment, the total spray demand is the sum of the spray control quantities of the first spray section, the second spray section, and the third spray section within the same control cycle; the initial spray control quantity includes the non-zero baseline spray quantity of each spray section.

[0038] S3. When the particulate matter concentration at the spray outlet is higher than the target particulate matter concentration and the operating pressure difference does not exceed the pressure difference threshold, the three-stage spray washing unit is determined to be in a non-clogging fine dispersed particle escape state. In the non-clogging fine dispersed particle escape state, the control unit redistributes part of the spray control quantity of the first spray section to the second and third spray sections, provided that the total spray demand does not increase or the increase does not exceed the preset ratio.

[0039] The determination of the non-clogging fine dispersed particle escape state includes: if the concentration of particulate matter at the spray outlet is higher than the target particulate matter concentration for at least two consecutive sampling periods, and the operating pressure difference does not exceed the pressure difference threshold, the three-stage spray washing unit is determined to be in the non-clogging fine dispersed particle escape state.

[0040] In the non-clogging fine dispersed particle escape state, the control unit will allocate the spray control amount deducted from the first spray section to the second and third spray sections; when the total spray demand increases, the increase in the total spray demand shall not exceed 10% of the total spray demand before entering the non-clogging fine dispersed particle escape state.

[0041] When the operating differential pressure exceeds the differential pressure threshold, the control unit stops executing the control process for the escape state of non-clogging fine dispersed particles, and controls the second and third spray sections to maintain a non-zero reference spray volume, while increasing the discharge frequency or replacement frequency of the dust-carrying washing liquid of the three-stage spray washing unit.

[0042] Specifically, in this embodiment, the non-clogging fine dispersed particle escape state means that the three-stage spray washing unit has not experienced significant clogging but still has a high concentration of particulate matter at the outlet; at this time, the spray control quantity is preferentially redistributed to the second and third spray sections, rather than increasing the spray control quantity of all spray sections as a whole.

[0043] S4. Determine the inter-segment residence time based on the effective gas volume between the second and third spray sections and the pre-treated exhaust gas volume flow rate after operating condition correction, and determine the compensation-enhanced spray trigger time of the third spray section relative to the second spray section based on the inter-segment residence time and the phase correction amount of the current control cycle.

[0044] The effective gas volume between the second and third spray sections is the net volume within the tower for the pretreated tail gas to circulate between the outlet section of the second spray section and the inlet section of the third spray section; the inter-section residence time is determined by the ratio of the effective gas volume to the pretreated tail gas volume flow rate after operating condition correction.

[0045] Specifically, in this embodiment, the inter-segment residence time is used to characterize the time required for residual fine dispersed particles to migrate from the second spray section to the third spray section with the pretreated exhaust gas; the phase correction amount is used to compensate for the time deviation caused by exhaust gas field fluctuations and spray response lag.

[0046] S5. Control the second spray section to enter the enhanced spray state within the first pulse window to form an enhanced coagulation droplet field of the first droplet spectrum; and control the third spray section to enter the enhanced spray state within the second pulse window corresponding to the compensation enhanced spray trigger time to form an end-compensation trapping droplet field of the second droplet spectrum different from the first droplet spectrum, so that the residual fine dispersed particles are first wetted and coagulated in the second spray section, and then compensated and trapped in the third spray section; wherein, the enhanced spray state is the state in which the spray control quantity of the corresponding spray section is higher than the non-zero reference spray quantity of the spray section, and the spray control quantity includes at least one of spray flow rate, spray pressure, pulse duty cycle or spray frequency; the second spray section and the third spray section are not in the enhanced spray state at the same time, and when any spray section is in the enhanced spray state, the other spray section maintains a non-zero reference spray quantity.

[0047] The first droplet spectrum and the second droplet spectrum are formed by the nozzle orifice diameter, spray pressure and spray flow rate of the corresponding spray section, respectively. The median particle size of the first droplet spectrum is larger than the median particle size of the second droplet spectrum, and the droplet number density of the second droplet spectrum in the corresponding spray droplet field is greater than the droplet number density of the first droplet spectrum in the corresponding spray droplet field.

[0048] The first and second pulse windows do not overlap in time; the start time of the second pulse window is the sum of the inter-segment dwell time and the phase correction amount after the start time of the first pulse window.

[0049] Specifically, in this embodiment, the first droplet spectrum is used to increase the wetting and coagulation probability of residual fine dispersed particles, and the second droplet spectrum is used to perform end-compensation capture of particles that still migrate with the exhaust gas after coagulation; the second spray section and the third spray section are not in enhanced spray state at the same time, so as to achieve spray peak transfer under the condition of limited total spray demand.

[0050] S6. After the second pulse window, obtain the decrease response of the particulate matter concentration at the spray outlet, and update the phase correction amount in the next control cycle according to the response offset of the decrease response relative to the preset response time. When the decrease response lags behind the preset response time, shift the compensation enhancement spray trigger time in the next control cycle backward; when the decrease response is earlier than the preset response time, shift the compensation enhancement spray trigger time in the next control cycle forward, so that the actual escaped fine dispersed particulate matter gas cloud migrates to the third spray section and enters the end compensation trapping droplet field, and obtains purified gas with a stable decrease in particulate matter concentration.

[0051] The drop response is the response formed when the particulate concentration at the spray outlet decreases to a preset drop range relative to the particulate concentration at the spray outlet when entering the non-clogging fine dispersed particle escape state. The response offset is the time difference between the actual response time and the preset response time. The control unit updates the phase correction amount in the next control cycle based on the time difference. The third spray section includes multiple compensated spray zones distributed along the cross-section of the three-stage spray washing unit. The parameter acquisition unit includes outlet end particulate detection points set corresponding to each compensated spray zone. The control unit determines the escape channel region of fine dispersed particles based on the particulate concentration detected by each outlet end particulate detection point, and increases the spray control amount of the compensated spray zone corresponding to the escape channel region within the second pulse window.

[0052] Specifically, in this embodiment, the descent response is used to determine whether the end-compensation trapping droplet field matches the arrival time of the actual escaped fine dispersed particulate air mass; by updating the phase correction amount in the next control cycle, the compensation trapping time of the third spraying section is gradually made consistent with the migration time of the actual escaped air mass.

[0053] Example 2

[0054] like Figure 2 As shown, this embodiment further explains the process of determining the escape state of non-clogging fine dispersed particles based on embodiment 1.

[0055] In this embodiment, the parameter acquisition unit collects the particulate matter concentration at the spray outlet and the operating pressure difference of the three-stage spray washing unit according to a preset sampling period, and sends the acquisition results to the control unit. The control unit compares the particulate matter concentration at the spray outlet with the target particulate matter concentration, and at the same time compares the operating pressure difference with the pressure difference threshold.

[0056] If the particulate matter concentration at the spray outlet is higher than the target particulate matter concentration for at least two consecutive sampling periods, and the operating differential pressure does not exceed the differential pressure threshold, the control unit determines that the three-stage spray scrubbing unit is in a non-clogging, finely dispersed particle escape state. This state indicates that the three-stage spray scrubbing unit has not experienced significant clogging or abnormal droplet retention differential pressure, but there are still residual finely dispersed particles that escape with the exhaust gas after passing through the spray section.

[0057] After determining that the non-clogging fine dispersed particles are in an escape state, the control unit does not increase the spray control amount of all spray sections as a whole. Instead, under the condition that the total spray demand does not increase or the increase does not exceed the preset ratio, it redistributes part of the spray control amount of the first spray section to the second and third spray sections to improve the enhanced coagulation and end-compensation collection capabilities for residual fine dispersed particles.

[0058] When the operating differential pressure exceeds the differential pressure threshold, the control unit does not determine that it is a non-clogging fine dispersed particle escape state, but switches to differential pressure abnormality treatment, so that the second and third spray sections maintain a non-zero reference spray volume, and increases the discharge frequency or replacement frequency of the dust-carrying washing liquid of the three-stage spray washing unit.

[0059] Example 3

[0060] like Figure 3 As shown, this embodiment further explains the phase misalignment pulse compensation control process based on inter-segment dwell time and phase correction amount, based on embodiment 1.

[0061] In this embodiment, the control unit determines the inter-stage residence time based on the effective gas volume between the second and third spray sections and the pre-treated exhaust gas volumetric flow rate after operating condition correction. The inter-stage residence time characterizes the time required for residual fine dispersed particles to migrate from the second spray section to the third spray section with the pre-treated exhaust gas. Specifically, the larger the effective gas volume, the longer the inter-stage residence time; the larger the pre-treated exhaust gas volumetric flow rate after operating condition correction, the shorter the inter-stage residence time.

[0062] Specifically, in this embodiment, the effective gas volume between the second and third spray sections is 3 m³, and the pre-treated exhaust gas volumetric flow rate detected by the parameter acquisition unit, after correction for pre-treated exhaust gas temperature and pressure, is 1 m³ / s. Based on this, the control unit determines that the time required for the pre-treated exhaust gas to pass through the 3 m³ effective gas volume is 3 seconds, therefore the inter-section residence time is determined to be 3 seconds.

[0063] After determining the inter-segment dwell time, the control unit, in conjunction with the phase correction amount of the current control cycle, determines the trigger time for the compensated enhanced spray of the third spray segment relative to the second spray segment. The phase correction amount is used to compensate for time deviations caused by fluctuations in the rotary kiln tail gas conditions, changes in the flow field within the tower, and spray response lag. Specifically, in the initial control cycle, the phase correction amount can be set to zero or based on historical operating data; in subsequent control cycles, the phase correction amount is updated according to the decrease in particulate matter concentration at the spray outlet.

[0064] Within the current control cycle, the trigger time for the second spray section to enter the enhanced spray state is 10 seconds, the inter-segment dwell time is 3 seconds, and the phase correction amount for the current control cycle is 0.5 seconds. Therefore, the control unit determines the trigger time for the compensated enhanced spray of the third spray section to be 13.5 seconds. The third spray section does not enter the enhanced spray state immediately after the second spray section, but rather when the residual fine dispersed particles migrate with the pretreated exhaust gas to the vicinity of the third spray section.

[0065] After entering the non-clogging, finely dispersed particle escape state, the control unit controls the second spray section to enter an enhanced spray state within the first pulse window to form an enhanced coagulation droplet field of the first droplet spectrum; and according to the trigger time of the compensated enhanced spray, controls the third spray section to enter an enhanced spray state within the second pulse window to form an end-compensated trapping droplet field of the second droplet spectrum. The first pulse window is the duration interval during which the second spray section enters the enhanced spray state and forms the enhanced coagulation droplet field, and the second pulse window is the duration interval during which the third spray section enters the enhanced spray state and forms the end-compensated trapping droplet field.

[0066] Within this control cycle, the first pulse window is set from 10s to 13.5s, and the second pulse window begins at 13.5s and lasts until 17.5s. The first and second pulse windows do not overlap in time, ensuring that the second and third spray sections are not simultaneously in enhanced spray mode. Therefore, residual fine dispersed particles not completely captured in the second spray section can enter the end-compensation droplet capture field as they migrate with the pretreated exhaust gas to the third spray section.

[0067] As the data link for spray control, before entering the non-clogging fine dispersed particle escape state, the control unit sets the spray control quantities of the first, second, and third spray sections to 40 L / min, 30 L / min, and 30 L / min, respectively, with a total spray demand of 100 L / min. After entering the non-clogging fine dispersed particle escape state, the control unit adjusts the spray control quantity of the first spray section to 30 L / min and uses the deducted 10 L / min as the pulse-enhanced spray control quantity. Within the first pulse window, the spray control quantity of the second spray section is increased to 40 L / min, while the third spray section maintains 30 L / min. Within the second pulse window, the spray control quantity of the third spray section is increased to 40 L / min, while the second spray section maintains 30 L / min. Thus, within the two pulse windows, the sum of the three spray control quantities does not exceed 100 L / min, achieving a phase shift of the spray peak between the second and third spray sections.

[0068] In the aforementioned control process, the enhanced coagulation droplet field of the first droplet spectrum is used to wet and coagulate residual fine dispersed particles, while the end-compensation trapping droplet field of the second droplet spectrum is used to compensate for and trap particles that still migrate with the pretreatment exhaust gas after being treated in the second spray section. Therefore, the compensation trapping in the third spray section is neither a fixed-time delay spray nor an overall increase in spray volume. Instead, it compensates for the migration time of residual fine dispersed particles with the pretreatment exhaust gas between the second and third spray sections, matching the end-compensation trapping droplet field with the arrival time of the actual escaping fine dispersed particle gas cloud, thereby improving the dynamic trapping effect of residual fine dispersed particles in the rotary kiln pretreatment exhaust gas.

[0069] Example 4

[0070] like Figure 4 As shown, this embodiment further explains the formation methods of the first droplet spectrum and the second droplet spectrum based on Embodiment 1.

[0071] In this embodiment, the second spray section is used to form an enhanced coagulation droplet field for the first droplet spectrum, and the third spray section is used to form an end-compensation trapping droplet field for the second droplet spectrum. The first droplet spectrum and the second droplet spectrum are formed by adjusting one or more of the following: nozzle orifice diameter, spray pressure, spray flow rate, pulse duty cycle, or spray frequency of the corresponding spray section.

[0072] Specifically, the second spray section can employ a relatively large nozzle orifice diameter and a relatively low atomization pressure, resulting in a larger median particle size in the first droplet spectrum. When the larger droplets come into contact with the remaining finely dispersed particles in the second spray section, it helps to increase the probability of particle wetting, collision, and agglomeration, causing some of the finely dispersed particles to form wetted particles with increased particle size.

[0073] The third spray section can employ a relatively small nozzle orifice diameter and a relatively high atomization pressure to achieve a high droplet number density in the second droplet spectrum. The second droplet spectrum is used to compensate for and capture particles that still migrate with the pretreated exhaust gas after being treated by the second spray section in the end-of-pipe compensation and capture droplet field, thereby reducing the possibility of residual fine dispersed particles escaping with the airflow.

[0074] In one specific embodiment, the median particle size of the first droplet spectrum is larger than that of the second droplet spectrum, and the droplet number density of the second droplet spectrum in the corresponding spray droplet field is greater than that of the first droplet spectrum in the corresponding spray droplet field. Therefore, the second and third spray sections are not two equivalent spray sections, but rather respectively undertake the functions of enhanced coagulation and end-of-pipe compensation collection, so that residual fine dispersed particles are first wetted and coagulated, and then compensated and collected.

[0075] Example 5

[0076] like Figure 5 As shown, this embodiment further explains the process of updating the phase correction amount based on the decrease in particulate matter concentration at the spray outlet, based on Embodiments 1 and 3.

[0077] In this embodiment, after the second pulse window, the control unit continues to acquire the particulate matter concentration at the spray outlet and determines whether the particulate matter concentration at the spray outlet has decreased relative to the particulate matter concentration at the spray outlet when entering the non-clogging fine dispersed particle escape state. The decrease response is the response formed when the particulate matter concentration at the spray outlet decreases to a preset decrease range, and the response offset is the time difference between the actual response time of the decrease response and the preset response time.

[0078] Specifically, within a control cycle, if the particulate matter concentration at the spray outlet when entering the non-clogging fine dispersed particle escape state is 80 mg / m³, and the target particulate matter concentration is 50 mg / m³, then the preset decrease range can be set to half the difference between the two, i.e., 15 mg / m³. When the particulate matter concentration at the spray outlet drops to 65 mg / m³, the control unit records this moment as the actual response time. If the preset response time is 5 seconds after the end of the second pulse window, and the actual response time is 7 seconds after the end of the second pulse window, then the decrease response is determined to be lagging behind the preset response time; if the actual response time is 3 seconds after the end of the second pulse window, then the decrease response is determined to be earlier than the preset response time. When the decrease response lags behind the preset response time, the control unit determines that the actual escaped fine dispersed particle cloud arrives at the third spray section later than the current compensation window, thus shifting the compensation-enhanced spray trigger time in the next control cycle later; when the decrease response is earlier than the preset response time, the control unit determines that the actual escaped fine dispersed particle cloud arrives at the third spray section earlier than the current compensation window, thus shifting the compensation-enhanced spray trigger time in the next control cycle earlier.

[0079] When the descent response lags behind the preset response time, the control unit shifts the trigger time of the compensation-enhanced spray in the next control cycle to the later stage; when the descent response is earlier than the preset response time, the control unit shifts the trigger time of the compensation-enhanced spray in the next control cycle to the earlier stage, so that the end compensation-capture droplet field of the third spray section gradually matches the arrival time of the actual escaped fine dispersed particulate air mass.

[0080] In this way, the control unit does not adjust the spray volume based solely on the concentration of particulate matter at the spray outlet in a single spray cycle. Instead, it updates the phase correction amount in the next control cycle based on the decrease in the concentration of particulate matter at the spray outlet after the second pulse window, so that the compensation collection time of the third spray stage can be adaptively corrected according to the changes in the operating conditions of the rotary kiln tail gas.

[0081] Example 6

[0082] like Figure 6 As shown, this embodiment further explains the compensation spray zone and pressure difference abnormality treatment based on embodiment 1.

[0083] In this embodiment, the third spray section includes multiple compensating spray zones distributed along the cross-section of the three-stage spray washing unit. The parameter acquisition unit includes outlet-end particulate matter detection points corresponding to each compensating spray zone. The control unit determines the escape channel region of finely dispersed particles based on the particulate matter concentration detected by each outlet-end particulate matter detection point, and increases the spray control quantity of the compensating spray zone corresponding to the escape channel region within a second pulse window to perform directional compensation and capture of locally escaped particles.

[0084] When the operating differential pressure exceeds the differential pressure threshold, the control unit stops executing the control process for the escape state of non-clogging fine dispersed particles, and controls the second and third spray sections to maintain a non-zero reference spray volume. At the same time, it increases the discharge frequency or replacement frequency of the dust-laden washing liquid in the three-stage spray washing unit to reduce the dust-laden liquid load in the tower and prevent the operating differential pressure from continuing to rise.

[0085] Through the above methods, this embodiment can achieve zoned compensation and collection in the state of non-clogging fine dispersed particles escaping, and switch to dust-carrying washing liquid discharge or replacement treatment when the pressure difference is abnormal, thereby improving the system's operational stability.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A cyclone bag filter dust collector and a three-stage spray exhaust gas purification system, characterized in that, The system includes a cyclone bag pretreatment unit, a three-stage spray washing unit, a parameter acquisition unit, and a control unit. The three-stage spray washing unit sequentially forms a first spray section, a second spray section, and a third spray section along the exhaust gas direction. The control unit is configured to execute the following control process: S1. The parameter acquisition unit acquires the pre-treated exhaust gas parameters of the pre-treated exhaust gas output by the cyclone bag pre-treatment unit. The pre-treated exhaust gas is the airflow formed after the dust-laden exhaust gas of the rotary kiln is treated by the cyclone bag pre-treatment unit and carries residual fine dispersed particles. The pre-treated exhaust gas parameters include the pre-treated exhaust gas volumetric flow rate, the particulate matter concentration at the spray inlet, the particulate matter concentration at the spray outlet, and the operating pressure difference of the three-stage spray washing unit. S2. Determine the total spray demand of the three-stage spray scrubbing unit based on the pre-treated exhaust gas volume flow rate and the particulate matter concentration at the spray inlet, and generate the initial spray control quantities for the first spray section, the second spray section, and the third spray section; S3. When the particulate matter concentration at the spray outlet is higher than the target particulate matter concentration and the operating pressure difference does not exceed the pressure difference threshold, the three-stage spray washing unit is determined to be in a non-clogging fine dispersed particle escape state; in the non-clogging fine dispersed particle escape state, the control unit, under the condition that the total spray demand does not increase or the increase does not exceed a preset ratio, redistributes part of the spray control quantity of the first spray section to the second spray section and the third spray section; S4. Determine the inter-segment residence time based on the effective gas volume between the second spray section and the third spray section and the pre-treated exhaust gas volume flow rate after operating condition correction, and determine the compensation enhanced spray trigger time of the third spray section relative to the second spray section based on the inter-segment residence time and the phase correction amount of the current control cycle. S5. Control the second spray section to enter the enhanced spray state within the first pulse window, and control the third spray section to enter the enhanced spray state within the second pulse window corresponding to the compensation enhanced spray trigger time, so as to form a terminal compensation trapping droplet field of the second droplet spectrum different from the first droplet spectrum, so that the residual fine dispersed particles are first wetted and agglomerated in the second spray section, and then compensated and trapped in the third spray section. The enhanced spray state is the state in which the spray control quantity of the corresponding spray section is higher than the non-zero reference spray quantity of the spray section. The spray control quantity includes at least one of spray flow rate, spray pressure, pulse duty cycle or spray frequency. The second spray section and the third spray section are not in the enhanced spray state at the same time. When any spray section is in the enhanced spray state, the other spray section maintains a non-zero reference spray quantity. S6. After the second pulse window, obtain the decrease response of the particulate matter concentration at the spray outlet, and update the phase correction amount in the next control cycle according to the response offset of the decrease response relative to the preset response time. When the decrease response lags behind the preset response time, shift the compensation enhancement spray trigger time in the next control cycle. When the decrease response is earlier than the preset response time, the trigger time of the compensation-enhanced spray in the next control cycle is shifted forward, so that the actual escaped fine dispersed particulate air mass migrates to the third spray section and enters the end compensation trapping droplet field, and obtains purified gas with a stable decrease in particulate matter concentration.

2. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: The pretreated exhaust gas parameters also include pretreated exhaust gas temperature and pretreated exhaust gas pressure; the pretreated exhaust gas volumetric flow rate after operating condition correction is calculated based on the pretreated exhaust gas volumetric flow rate, the pretreated exhaust gas temperature, and the pretreated exhaust gas pressure.

3. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: The effective gas volume between the second spray section and the third spray section is the net volume within the tower from the outlet section of the second spray section to the inlet section of the third spray section for the pretreated tail gas to circulate; the inter-section residence time is determined by the ratio of the effective gas volume to the pretreated tail gas volume flow rate after operating condition correction.

4. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: The determination of the non-clogging fine dispersed particle escape state includes: if the concentration of particulate matter at the spray outlet is higher than the target particulate matter concentration for at least two consecutive sampling periods, and the operating pressure difference does not exceed the pressure difference threshold, the three-stage spray washing unit is determined to be in the non-clogging fine dispersed particle escape state.

5. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: In the non-clogging fine dispersed particle escape state, the control unit allocates the spray control amount deducted from the first spray section to the second spray section and the third spray section; when the total spray demand increases, the increase in the total spray demand does not exceed 10% of the total spray demand before entering the non-clogging fine dispersed particle escape state.

6. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: The first droplet spectrum and the second droplet spectrum are formed by the nozzle orifice diameter, spray pressure and spray flow rate of the corresponding spray section, respectively. The median particle size of the first droplet spectrum is larger than the median particle size of the second droplet spectrum, and the droplet number density of the second droplet spectrum in the corresponding spray droplet field is greater than the droplet number density of the first droplet spectrum in the corresponding spray droplet field.

7. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: The first pulse window and the second pulse window do not overlap in time; the starting time of the second pulse window is the time after the starting time of the first pulse window, which is the sum of the inter-segment dwell time and the phase correction amount.

8. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: The decrease response is the response formed when the concentration of particulate matter at the spray outlet decreases to a preset decrease range relative to the concentration of particulate matter at the spray outlet when entering the non-clogging fine dispersed particle escape state. The response offset is the time difference between the actual response time of the decrease response and the preset response time. The control unit updates the phase correction amount in the next control cycle according to the time difference.

9. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: The third spray section includes multiple compensation spray zones distributed along the cross-section of the three-stage spray washing unit. The parameter acquisition unit includes an outlet end particulate matter detection point corresponding to each compensation spray zone. The control unit determines the escape channel region of fine dispersed particles based on the particulate matter concentration detected by each outlet end particulate matter detection point, and increases the spray control amount of the compensation spray zone corresponding to the escape channel region within the second pulse window.

10. The cyclone bag filter and three-stage spray exhaust gas purification system according to claim 1, characterized in that: When the operating pressure difference exceeds the pressure difference threshold, the control unit stops executing the control process for the escape state of the non-clogging fine dispersed particles, and controls the second spray section and the third spray section to maintain the non-zero reference spray volume, while increasing the discharge frequency or replacement frequency of the dust-carrying washing liquid of the three-stage spray washing unit.

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