Method and device for cleaning a bag filter

Abstract

The application discloses a dust cleaning method and dust cleaning device for a bag-type dust collector. The dust cleaning method comprises the following steps: detecting the flue gas inlet pipe pressure and flue gas outlet pipe pressure of the bag-type dust collector and the frequency of the induced draft fan; determining the stop dust cleaning pressure difference range and the start dust cleaning pressure difference range according to the frequency of the induced draft fan; stopping dust cleaning if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure falls to the stop dust cleaning pressure difference range; and starting dust cleaning if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure rises to the start dust cleaning pressure difference range. The dust cleaning method for the bag-type dust collector avoids the situation of over-dust cleaning or under-dust cleaning. Moreover, the stop dust cleaning pressure difference range and the start dust cleaning pressure difference range are both associated with the frequency of the induced draft fan, the accuracy of the stop dust cleaning pressure difference range and the start dust cleaning pressure difference range is improved, the dust cleaning effect is improved, and the situation of over-dust cleaning or under-dust cleaning is further avoided.

Description

Technical Field

[0001] This invention relates to the field of baghouse dust collector technology, and more specifically, to a dust removal method and dust removal device for a baghouse dust collector. Background Technology

[0002] A baghouse dust collector is a dry dust filtration device suitable for collecting fine, dry, non-fibrous dust. The filter bags are made of woven filter cloth or non-woven felt, utilizing the filtration effect of the fibrous fabric to filter dust-laden gas. When the dust-laden gas enters the baghouse dust collector, larger, heavier dust particles settle due to gravity and fall into the dust hopper. Gas containing finer dust particles is purified by trapping the dust as it passes through the filter bags.

[0003] To ensure effective dust removal and prevent filter bags from spontaneously combusting due to heat buildup, regular cleaning of the filter bags is necessary. Currently, periodic cleaning is the primary method, such as blowing air every 5 minutes. However, improper interval settings can lead to over- or under-blowing. If the interval is too short, frequent blowing can damage the filter bags and shorten their lifespan. Conversely, if the interval is too long, accumulated dust cannot be removed promptly, causing heat buildup and posing a risk of spontaneous combustion.

[0004] In summary, how to clean the filter bags of baghouse dust collectors to avoid over- or under-cleaning is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a dust removal method for a bag filter to avoid over- or under-cleaning. Another purpose of this invention is to provide a dust removal device for a bag filter.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for cleaning a bag filter includes the following steps:

[0008] Detect the flue gas inlet and outlet pressures of the bag filter, as well as the frequency of the induced draft fan;

[0009] The pressure differential range for stopping and starting dust removal is determined based on the frequency of the induced draft fan.

[0010] If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the range where cleaning is stopped, cleaning is stopped; if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure rises to the range where cleaning is started, cleaning is started.

[0011] The induced draft fan is installed on the flue gas outlet pipe of the bag filter, and the upper limit of the differential pressure range for stopping dust removal is less than the lower limit of the differential pressure range for starting dust removal.

[0012] Preferably, the frequency of the induced draft fan has at least one frequency range, and the stop cleaning pressure difference range and the start cleaning pressure difference range both correspond one-to-one with the frequency range.

[0013] Preferably, there are at least two frequency intervals, and no two frequency intervals overlap.

[0014] The upper limit of the differential pressure range for stopping dust cleaning and the lower limit of the differential pressure range for starting dust cleaning are both positively correlated with the upper limit of the frequency range.

[0015] Preferably, at the same frequency of the induced draft fan, the determined range of the stop cleaning pressure difference is less than a first set value, the obtained range of the start cleaning pressure difference is greater than a second set value, and the first set value is less than the second set value.

[0016] Preferably, the step of initiating dust removal specifically involves: activating the pulse jet module to inject gas into the filter bags of the bag filter to remove dust.

[0017] Preferably, the dust removal process further includes the following steps:

[0018] If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the injection pressure of the injection module is controlled to be positively correlated with the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure.

[0019] If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is less than the lower limit of the pressure difference range, the jetting module is controlled to perform jetting at the minimum jetting pressure.

[0020] If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is greater than the upper limit of the pressure difference range, the injection module is controlled to perform injection at the maximum injection pressure.

[0021] Preferably, if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the blowing pressure of the blowing module is controlled to have a linear relationship with the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure.

[0022] Preferably, the blowing module includes at least two blowing units arranged in sequence, and any two blowing units are used to blow gas onto different filter bags;

[0023] The steps to initiate the dust removal process specifically include the following steps:

[0024] First, control the first-ordered pulse-jet unit to pulse. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the first-ordered pulse-jet unit has been pulsed for a set time, then control the second-ordered pulse-jet unit to pulse.

[0025] Preferably, the filter bags in the bag filter are divided into a first filter bag group and a second filter bag group, with the first filter bag group being close to the flue gas inlet of the bag filter and the second filter bag group being far away from the flue gas inlet of the bag filter.

[0026] The blowing module includes at least two blowing units. All the blowing units are divided into a first blowing unit that blows the first filter bag group and a second blowing unit that blows the second filter bag group. The blowing nozzle of the first blowing unit is larger than the blowing nozzle of the second blowing unit.

[0027] The dust removal method for a bag filter provided by this invention stops dust removal when the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe decreases to the stop dust removal pressure difference range, and starts dust removal when the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe increases to the start dust removal pressure difference range. Since the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe can reflect the dust accumulation on the filter bags, it effectively avoids over- or under-duration dust removal. Moreover, by linking both the stop dust removal pressure difference range and the start dust removal pressure difference range to the frequency of the induced draft fan, the accuracy of the stop dust removal pressure difference range and the start dust removal pressure difference range is improved, thereby improving the dust removal effect and further avoiding over- or under-duration dust removal.

[0028] Based on the dust removal method for bag filters provided above, the present invention also provides a dust removal device for bag filters, the dust removal device for bag filters comprising:

[0029] The first detector is used to detect the flue gas inlet pipe pressure of the bag filter;

[0030] The second detector is used to detect the flue gas outlet pressure of the bag filter;

[0031] The third detector is used to detect the frequency of the induced draft fan;

[0032] The determining module is used to determine the stop cleaning pressure differential range and the start cleaning pressure differential range based on the frequency of the induced draft fan;

[0033] The dust removal module is used to clean the accumulated dust on the filter bags in the bag filter.

[0034] The first control module controls the cleaning module to stop cleaning if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the stop cleaning pressure difference range; and controls the cleaning module to start cleaning if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure rises to the start cleaning pressure difference range.

[0035] The induced draft fan is installed on the flue gas outlet pipe, and the upper limit of the pressure difference range for stopping the cleaning is less than the lower limit of the pressure difference range for starting the cleaning.

[0036] Preferably, the determining module includes:

[0037] The storage unit is used to store the frequency of the induced draft fan, and the corresponding stop cleaning pressure differential range and start cleaning pressure differential range at the frequency of the induced draft fan;

[0038] The acquisition unit is used to acquire the stop cleaning pressure differential range and start cleaning pressure differential range from the storage unit according to the frequency of the induced draft fan.

[0039] Preferably, the storage unit stores the frequency of the induced draft fan in the form of frequency intervals, and there is at least one frequency interval. The pressure difference range for stopping dust cleaning and the pressure difference range for starting dust cleaning both correspond one-to-one with the frequency intervals.

[0040] Preferably, there are at least two frequency intervals, and no two frequency intervals overlap.

[0041] The upper limit of the differential pressure range for stopping dust cleaning and the lower limit of the differential pressure range for starting dust cleaning are both positively correlated with the upper limit of the frequency range.

[0042] Preferably, at the same frequency of the induced draft fan, the range of pressure difference for stopping dust cleaning determined by the determining module is less than a first set value, the range of pressure difference for starting dust cleaning determined by the determining module is greater than a second set value, and the first set value is less than the second set value.

[0043] Preferably, the dust removal module is a jetting module used to blow gas into the filter bag for dust removal.

[0044] Preferably, the dust removal device of the bag filter further includes a second control module;

[0045] If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the second control module is used to control the injection pressure of the injection module to be positively correlated with the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure.

[0046] If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is less than the lower limit of the pressure difference range, the second control module is used to control the injection module to perform injection at the minimum injection pressure.

[0047] If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is greater than the upper limit of the pressure difference range, the second control module is used to control the injection module to perform injection at the maximum injection pressure.

[0048] Preferably, if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the second control module is used to control the injection pressure of the injection module to be linearly related to the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure.

[0049] Preferably, the blowing module includes at least two blowing units arranged in sequence, and any two blowing units are used to blow gas onto different filter bags;

[0050] The first control module is used to first control the first-ordered pulse-jet unit to pulse. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the first-ordered pulse-jet unit has been pulsed for a set time, then the second-ordered pulse-jet unit will be controlled to pulse. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0052] Figure 1 A flowchart of a dust removal method for a bag filter provided in an embodiment of the present invention;

[0053] Figure 2 A graph showing the functional relationship between the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure and the blowing pressure in the dust removal method of the bag filter provided in the embodiment of the present invention.

[0054] Figure 3 This is a schematic diagram of the structure of the dust removal device for a bag filter provided in an embodiment of the present invention;

[0055] Figure 4 This is a schematic diagram of the structure of the dust removal module in the dust removal device of the bag filter provided in an embodiment of the present invention. Detailed Implementation

[0056] 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.

[0057] like Figure 1 As shown, the dust removal method for a bag filter provided in this embodiment of the invention specifically includes the following steps:

[0058] S11) Detect the flue gas inlet and outlet pressures of the bag filter, as well as the frequency of the induced draft fan:

[0059] Specifically, the induced draft fan is installed on the flue gas outlet pipe of the bag filter. The flue gas inlet pipe pressure is the same as the flue gas pressure inside the bag filter's flue gas inlet pipe, and the flue gas outlet pipe pressure is the same as the flue gas pressure inside the bag filter's flue gas outlet pipe. To improve the dust removal effect, the flue gas outlet pipe pressure is preferentially measured at a position near the flue gas outlet of the bag filter, and the flue gas inlet pipe pressure is measured at a position near the flue gas inlet of the bag filter.

[0060] S12) Determine the pressure differential range for stopping and starting dust removal based on the frequency of the induced draft fan:

[0061] The upper limit of the above-mentioned differential pressure range for stopping dust cleaning is less than the lower limit of the differential pressure range for starting dust cleaning.

[0062] In practical applications, the correspondence between the frequency of the induced draft fan and the range of pressure difference for stopping the dust removal process, as well as the correspondence between the frequency of the induced draft fan and the range of pressure difference for starting the dust removal process, can be found through experiments. Before the equipment leaves the factory, the range of pressure difference for stopping the dust removal process and the range of pressure difference for starting the dust removal process corresponding to the frequency of the induced draft fan should be determined.

[0063] In practical applications, under the same induced draft fan frequency, the determined stop cleaning pressure difference range can be no less than a first set value, and the obtained start cleaning pressure difference range can be greater than the first set value. Since there is a delay in the detection pressure and frequency, to avoid affecting cleaning due to this delay, it is preferable to select a stop cleaning pressure difference range less than the first set value and a start cleaning pressure difference range greater than a second set value under the same induced draft fan frequency, where the first set value is less than the second set value.

[0064] The specific values ​​of the first and second set values, as well as the difference between the first and second set values, can be set according to actual needs, and this embodiment does not limit them.

[0065] S13) If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the range where cleaning stops, then cleaning stops; if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure rises to the range where cleaning starts, then cleaning starts.

[0066] It should be noted that the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is used to determine the ash accumulation on the filter bags, thereby determining whether to start or stop the ash cleaning process. Initially, the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is assumed to be at its maximum.

[0067] The dust removal method for a bag filter provided in this invention stops dust removal when the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe decreases to the stop dust removal pressure difference range, and starts dust removal when the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe increases to the start dust removal pressure difference range. Since the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe can reflect the dust accumulation on the filter bags, it effectively avoids over- or under-duration dust removal. Moreover, by linking both the stop dust removal pressure difference range and the start dust removal pressure difference range to the frequency of the induced draft fan, the accuracy of the stop dust removal pressure difference range and the start dust removal pressure difference range is improved under the frequency of the induced draft fan, thereby improving the dust removal effect and further avoiding over- or under-duration dust removal. This achieves efficient dust removal, energy saving, and material saving.

[0068] The above-mentioned dust removal method for bag filters avoids over- or under-cleaning, thus preventing filter bags from burning due to untimely cleaning and damage due to excessive cleaning, thereby extending the service life of the filter bags.

[0069] Since the frequency of the induced draft fan is easily changed, in order to simplify the adjustment, in the above-mentioned dust removal method for bag filters, the frequency of the induced draft fan has at least one frequency range, and the pressure difference range for stopping dust removal and the pressure difference range for starting dust removal both correspond one-to-one with the frequency range.

[0070] The number and division of frequency intervals are selected according to actual needs, and this embodiment does not impose any limitations on this. Preferably, there are at least two frequency intervals, and no two frequency intervals overlap; the upper limit of the stop cleaning pressure differential range and the lower limit of the start cleaning pressure differential range are both positively correlated with the upper limit of the frequency interval.

[0071] Specifically, the pressure difference range for stopping and starting dust removal can be determined according to the frequency of the induced draft fan, referring to Table 1. The pressure difference between the flue gas inlet pressure and the flue gas outlet pressure is denoted as ΔP.

[0072] Table 1. Conditions for starting and stopping dust cleaning.

[0073]

[0074]

[0075]

[0076] In Table 1 above, taking 0 < Ф ≤ 15, ΔP < 300, the dust removal device stops, and 0 < Ф ≤ 15, ΔP > 400, the dust removal device starts as examples. When the frequency of the induced draft fan is in the frequency range (0, 15], ΔP < 300 is the range of pressure differential for stopping dust removal, and ΔP > 400 is the range of pressure differential for starting dust removal.

[0077] In practical applications, other frequency ranges can also be selected, and the stop cleaning pressure differential range and start cleaning pressure differential range can be adjusted accordingly, and are not limited to the above Table 1.

[0078] To facilitate dust removal, the dust removal method for the bag filter described above, specifically, involves initiating the dust removal process by using a pulse-jet cleaning module to blow gas into the filter bags of the bag filter. Specifically, the pulse-jet cleaning module blows air into the filter bags.

[0079] The specific structure of the spray module can be selected according to actual needs, and this embodiment does not limit it.

[0080] To avoid excessively low or high injection pressure, the injection pressure is controlled to protect the filter bags. Specifically, the cleaning process includes the following steps: if the pressure difference between the flue gas inlet and outlet pipes is within a certain range, the injection pressure of the injection module is controlled to be positively correlated with the pressure difference between the flue gas inlet and outlet pipes; if the pressure difference is less than the lower limit of the pressure difference range, the injection module is controlled to inject at the minimum injection pressure; if the pressure difference is greater than the upper limit of the pressure difference range, the injection module is controlled to inject at the maximum injection pressure. Figure 2 As shown, ΔP is the pressure difference between the flue gas inlet pressure and the flue gas outlet pressure.

[0081] It should be noted that the upper limit of the above pressure difference range is the maximum pressure difference between the flue gas inlet pressure and the flue gas outlet pressure, and the lower limit of the above pressure difference range is the minimum pressure difference between the flue gas inlet pressure and the flue gas outlet pressure. The above pressure difference range needs to be set according to the actual situation, as shown in Table 1 and... Figure 2 As shown, the pressure difference range is 400Pa-1000Pa, but this embodiment does not limit it.

[0082] If the pressure difference between the flue gas inlet and outlet pipes is within a certain range, the injection pressure of the control module is positively correlated with this pressure difference. Therefore, the injection pressure of the control module must have both a maximum and a minimum value. For example, if the pressure difference between the flue gas inlet and outlet pipes is within a certain range, the minimum injection pressure of the control module is 280 kPa, and the maximum injection pressure is 380 kPa. Therefore, 280 kPa is the minimum injection pressure of the control module, and 380 kPa is the maximum injection pressure.

[0083] Furthermore, if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the specified range, the injection pressure of the injection module is linearly related to the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure. Figure 2 As shown.

[0084] Of course, it is also possible to select a curve relationship between the injection pressure of the injection module and the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure if the pressure difference is within the pressure difference range, and it is not limited to the above embodiment.

[0085] In the above-mentioned dust removal method for bag filters, by controlling the blowing pressure, the filter bags can be effectively protected during the blowing process, preventing them from being continuously blown by high-pressure gas, thus achieving on-demand blowing.

[0086] To improve the dust removal efficiency, the above-mentioned pulse jet module includes at least two pulse jet units arranged in sequence, with any two pulse jet units used to spray gas onto different filter bags; the above-mentioned steps to start the dust removal process specifically include the following steps: first, control the pulse jet unit that is first arranged in sequence to spray; if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop dust removal pressure difference range after the pulse jet unit that is first arranged in sequence has sprayed for a set time, then control the pulse jet unit that is second arranged in sequence to spray.

[0087] Specifically, taking a system with three pulse-jet units as an example, namely pulse-jet unit a, pulse-jet unit b, and pulse-jet unit c, pulse-jet unit a is controlled first. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the stop cleaning pressure difference range after the set time of pulse-jet unit a, then pulse-jet is stopped. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the set time of pulse-jet unit a, then pulse-jet unit b is controlled to pulse. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the stop cleaning pressure difference range after the set time of pulse-jet unit b, then pulse-jet is stopped. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the set time of pulse-jet unit b, then pulse-jet unit c is controlled to pulse.

[0088] The above-mentioned time setting can be set according to actual needs. For example, the time setting is 3 minutes. This embodiment does not limit this.

[0089] In practical applications, due to the large number of filter bags in a baghouse dust collector, the number of pulse-jet cleaning units is also relatively large. For example, if there are 128 filter bags, there are 46 pulse-jet cleaning units, and each pulse-jet cleaning unit cleans at least three filter bags. The number of filter bags cleaned by any two pulse-jet cleaning units can be the same or different. In the above-described baghouse dust collector cleaning method, only one pulse-jet cleaning unit is controlled at a time, or only two pulse-jet cleaning units are controlled at a time; this embodiment does not limit this.

[0090] The dust removal method of the bag filter described above achieves efficient dust removal, protects the filter bags, and reduces waste of utilities such as gas by controlling the pulse jet unit to blow air in sequence.

[0091] In the aforementioned blowing module, to facilitate the sequential blowing of the blowing units and the control of the blowing pressure of the blowing units, each blowing unit is connected to the gas source through a gas supply branch pipe, and a regulating valve is installed on the gas supply branch pipe. This regulating valve can cut off the gas supply branch pipe, open the gas supply branch pipe, and regulate the gas pressure. The aforementioned gas supply branch pipes correspond one-to-one with the blowing units. For ease of control, the aforementioned regulating valve is a solenoid valve.

[0092] In the aforementioned baghouse dust collector, the filter bags are divided into a first filter bag group and a second filter bag group. The first filter bag group is closer to the flue gas inlet of the baghouse dust collector, while the second filter bag group is farther away from the flue gas inlet. Typically, the first filter bag group accumulates more dust. To improve cleaning efficiency, the aforementioned pulse-jet cleaning module includes at least two pulse-jet cleaning units. All pulse-jet cleaning units are divided into a first pulse-jet cleaning unit for cleaning the first filter bag group and a second pulse-jet cleaning unit for cleaning the second filter bag group. The nozzle of the first pulse-jet cleaning unit is larger than the nozzle of the second pulse-jet cleaning unit.

[0093] The aforementioned baghouse dust collector has a partition pedal inside its housing. The first filter bag assembly is located on one side of the partition pedal, and the second filter bag assembly is located on the other side. To facilitate gas delivery, there are two gas sources: one source supplies gas to the first pulse-jet cleaning unit, and the other source supplies gas to the second pulse-jet cleaning unit.

[0094] Based on the dust removal method for baghouse dust collectors provided in the above embodiments, this invention also provides a dust removal device for baghouse dust collectors, such as... Figure 3 As shown, the dust removal device of the bag filter includes: a first detector 300, a second detector 400, a third detector, a determination module, a dust removal module 100, and a first control module.

[0095] The system includes a first detector 300 for detecting the inlet pressure of the bag filter; a second detector 400 for detecting the outlet pressure of the bag filter; a third detector for detecting the frequency of the induced draft fan 240; a determination module for determining the stop cleaning pressure differential range and the start cleaning pressure differential range based on the frequency of the induced draft fan 240; a cleaning module 100 for cleaning the accumulated ash on the filter bags 250 in the bag filter; if the pressure difference between the inlet and outlet pressures of the flue gas drops to the stop cleaning pressure differential range, the first control module controls the cleaning module 100 to stop cleaning; if the pressure difference between the inlet and outlet pressures of the flue gas rises to the start cleaning pressure differential range, the first control module controls the cleaning module 100 to start; the induced draft fan 240 is located on the outlet pipe 220, and the upper limit of the stop cleaning pressure differential range is less than the lower limit of the start cleaning pressure differential range.

[0096] In the aforementioned baghouse dust collector cleaning device, the flue gas inlet pipe pressure is the same as the flue gas pressure inside the flue gas inlet pipe 210 of the baghouse dust collector, and the flue gas outlet pipe pressure is the same as the flue gas pressure inside the flue gas outlet pipe 220 of the baghouse dust collector. To improve the cleaning effect, the first detector 300 is preferably installed in the flue gas inlet pipe 210 near the flue gas inlet of the baghouse dust collector, and the second detector 400 is installed in the flue gas outlet pipe 220 near the flue gas outlet of the baghouse dust collector.

[0097] The types of the first detector 300, the second detector 400, and the third detector can be selected according to actual needs, and this embodiment does not limit them.

[0098] In practical applications, the correspondence between the frequency of the induced draft fan 240 and the range of pressure difference for stopping the dust removal process, as well as the correspondence between the frequency of the induced draft fan 240 and the range of pressure difference for starting the dust removal process, can be found through experiments. Before the equipment leaves the factory, the range of pressure difference for stopping the dust removal process and the range of pressure difference for starting the dust removal process corresponding to the frequency of the induced draft fan 240 should be determined.

[0099] To facilitate dust removal, the aforementioned determining module includes a storage unit and an acquisition unit. The storage unit stores the frequency of the induced draft fan 240, as well as the corresponding stop dust removal pressure differential range and start dust removal pressure differential range at the frequency of the induced draft fan 240. The acquisition unit acquires the stop dust removal pressure differential range and start dust removal pressure differential range from the storage unit based on the frequency of the induced draft fan 240.

[0100] It should be noted that the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is used to determine the ash accumulation on the filter bag 250, thereby determining whether to start or stop the ash cleaning process. Initially, the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is assumed to be at its maximum.

[0101] The dust removal device for a bag filter provided in this invention stops dust removal when the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe decreases to the stop dust removal pressure difference range, and starts dust removal when the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe increases to the start dust removal pressure difference range. Since the pressure difference between the flue gas inlet pipe and the flue gas outlet pipe can reflect the dust accumulation on the filter bag 250, it effectively avoids over- or under-duration dust removal. Moreover, by associating both the stop dust removal pressure difference range and the start dust removal pressure difference range with the frequency of the induced draft fan 240, the accuracy of the stop dust removal pressure difference range and the start dust removal pressure difference range is improved under the frequency of the induced draft fan 240, thereby improving the dust removal effect and further avoiding over- or under-duration dust removal. This achieves efficient dust removal, energy saving, and material saving.

[0102] The dust removal device of the bag filter avoids over- or under-cleaning, thus preventing the filter bag 250 from burning due to untimely cleaning and also preventing damage to the filter bag 250 due to excessive cleaning, thereby extending the service life of the filter bag 250.

[0103] Since the frequency of the induced draft fan 240 is prone to change, in order to simplify the adjustment, the above-mentioned storage unit stores the frequency of the induced draft fan 240 in the form of frequency intervals. There is at least one frequency interval, and the pressure difference range for stopping dust cleaning and the pressure difference range for starting dust cleaning correspond one-to-one with the frequency intervals.

[0104] The number and division of frequency intervals are selected according to actual needs, and this embodiment does not impose any limitations on this. Preferably, there are at least two frequency intervals, and no two frequency intervals overlap; the upper limit of the stop cleaning pressure differential range and the lower limit of the start cleaning pressure differential range are both positively correlated with the upper limit of the frequency interval.

[0105] Specifically, the pressure difference range for stopping and starting dust removal can be determined according to the frequency of the induced draft fan 240, referring to Table 1. The pressure difference between the flue gas inlet pressure and the flue gas outlet pressure is denoted as ΔP.

[0106] Table 1. Conditions for starting and stopping dust cleaning.

[0107]

[0108]

[0109]

[0110] In Table 1 above, taking 0 < Ф ≤ 15, ΔP < 300, the dust removal device stops, and 0 < Ф ≤ 15, ΔP > 400, the dust removal device starts as examples. When the frequency of the induced draft fan 240 is in the frequency range (0, 15], ΔP < 300 is the range of pressure differential for stopping dust removal, and ΔP > 400 is the range of pressure differential for starting dust removal.

[0111] In practical applications, other frequency ranges can also be selected, and the stop cleaning pressure differential range and start cleaning pressure differential range can be adjusted accordingly, and are not limited to the above Table 1.

[0112] In practical applications, at the same frequency of the induced draft fan 240, the determined stop cleaning pressure difference range can be no less than a first set value, and the obtained start cleaning pressure difference range can be greater than the first set value. Since there is a delay in the detection pressure and frequency, to avoid affecting cleaning due to this delay, it is preferable to select a stop cleaning pressure difference range less than the first set value and a start cleaning pressure difference range greater than a second set value at the same frequency of the induced draft fan 240, where the first set value is less than the second set value.

[0113] The specific values ​​of the first and second set values, as well as the difference between the first and second set values, can be set according to actual needs, and this embodiment does not limit them.

[0114] To facilitate dust removal, the aforementioned dust removal module 100 is a jetting module used to blow gas into the filter bag 250 for dust removal. Specifically, the jetting module blows air into the filter bag 250. This air is high-pressure air.

[0115] The specific structure of the spray module can be selected according to actual needs, and this embodiment does not limit it.

[0116] To prevent the blowing pressure from being too low or too high, the blowing pressure is controlled to protect the filter bag 250. Preferably, the dust removal device of the bag filter also includes a second control module.

[0117] Specifically, if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the second control module controls the injection pressure of the injection module to be positively correlated with the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure; if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is less than the lower limit of the pressure difference range, the second control module controls the injection module to inject at the minimum injection pressure; if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is greater than the upper limit of the pressure difference range, the second control module controls the injection module to inject at the maximum injection pressure. Figure 2 As shown, ΔP is the pressure difference between the flue gas inlet pressure and the flue gas outlet pressure.

[0118] It should be noted that the upper limit of the above pressure difference range is the maximum pressure difference between the flue gas inlet pressure and the flue gas outlet pressure, and the lower limit of the above pressure difference range is the minimum pressure difference between the flue gas inlet pressure and the flue gas outlet pressure. The above pressure difference range needs to be set according to the actual situation, as shown in Table 1 and... Figure 2 As shown, the pressure difference range is 400Pa-1000Pa, but this embodiment does not limit it.

[0119] If the pressure difference between the flue gas inlet and outlet pipes is within a certain range, the injection pressure of the control module is positively correlated with this pressure difference. Therefore, the injection pressure of the control module must have both a maximum and a minimum value. For example, if the pressure difference between the flue gas inlet and outlet pipes is within a certain range, the minimum injection pressure of the control module is 280 kPa, and the maximum injection pressure is 380 kPa. Therefore, 280 kPa is the minimum injection pressure of the control module, and 380 kPa is the maximum injection pressure.

[0120] Furthermore, if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within a certain range, the second control module is used to control the injection pressure of the injection module to have a linear relationship with the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure, such as... Figure 2 As shown.

[0121] Of course, it is also possible to select a curve relationship between the injection pressure of the injection module and the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure if the pressure difference is within the pressure difference range, and it is not limited to the above embodiment.

[0122] In the dust removal device of the bag filter described above, the blowing pressure is controlled by the second control module, which can effectively protect the filter bag 250 during the blowing process, so that the filter bag 250 is protected from continuous high-pressure gas blowing, and the blowing is achieved on demand.

[0123] To improve the cleaning efficiency, the above-mentioned pulse jet module includes at least two pulse jet units arranged in sequence. Any two pulse jet units are used to inject gas into different filter bags 250. The first control module is used to control the pulse jet unit that is in the first position to inject gas. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the pulse jet unit that is in the first position has been injecting gas for a set time, then the pulse jet unit that is in the second position will be controlled to inject gas.

[0124] Specifically, taking a system with three pulse-jet units as an example, namely pulse-jet unit a, pulse-jet unit b, and pulse-jet unit c, pulse-jet unit a is controlled first. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the stop cleaning pressure difference range after the set time of pulse-jet unit a, then pulse-jet is stopped. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the set time of pulse-jet unit a, then pulse-jet unit b is controlled to pulse. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the stop cleaning pressure difference range after the set time of pulse-jet unit b, then pulse-jet is stopped. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the set time of pulse-jet unit b, then pulse-jet unit c is controlled to pulse.

[0125] The above-mentioned time setting can be set according to actual needs. For example, the time setting is 3 minutes. This embodiment does not limit this.

[0126] In practical applications, because there are many filter bags 250 in a baghouse dust collector, the number of pulse-jet cleaning units is also relatively large. For example, if there are 128 filter bags 250 and 46 pulse-jet cleaning units, each pulse-jet cleaning unit must clean at least three filter bags 250. Figure 4 As shown. The number of filter bags 250 blown by any two pulse-jet units 46 can be the same or different. In the dust removal device of the bag filter described above, the first control module controls only one pulse-jet unit to blow at a time, or controls only two pulse-jet units to blow at a time. This embodiment does not limit this.

[0127] The dust removal device of the bag filter mentioned above achieves efficient dust removal, protects the filter bag 250, and reduces the waste of gas and other utilities by controlling the jet cleaning unit to spray in sequence.

[0128] In the aforementioned blowing module, to facilitate the sequential blowing of the blowing units and the control of the blowing pressure of the blowing units, each blowing unit is connected to the air source 130 via an air supply branch pipe 120. A regulating valve 110 is installed on the air supply branch pipe 120. This regulating valve 110 can cut off or open the air supply branch pipe 120, and can also regulate the gas pressure. Each air supply branch pipe 120 corresponds to one blowing unit. For ease of control, the regulating valve 110 is a solenoid valve. The first control module controls the blowing of the blowing units by controlling the opening and closing of the solenoid valve, and the second control module controls the blowing pressure of the blowing units by controlling the opening degree of the solenoid valve.

[0129] In the aforementioned baghouse dust collector, the filter bags 250 are divided into a first filter bag group and a second filter bag group. The first filter bag group is closer to the flue gas inlet of the baghouse dust collector, while the second filter bag group is farther away from the flue gas inlet. Typically, the first filter bag group accumulates more dust. To improve cleaning efficiency, the aforementioned pulse-jet cleaning module includes at least two pulse-jet cleaning units. All pulse-jet cleaning units are divided into a first pulse-jet cleaning unit for cleaning the first filter bag group and a second pulse-jet cleaning unit for cleaning the second filter bag group. The nozzle of the first pulse-jet cleaning unit is larger than that of the second pulse-jet cleaning unit.

[0130] The aforementioned bag filter housing is equipped with a separating pedal 260. The first filter bag assembly is located on one side of the separating pedal 260, and the second filter bag assembly is located on the other side of the separating pedal 260. To facilitate gas delivery, there are two gas sources 130: one gas source 130 is used to supply gas to the first pulse-jet unit, and the other gas source 130 is used to supply gas to the second pulse-jet unit.

[0131] The type of bag filter mentioned above can be selected according to actual needs. For example, the bag filter mentioned above is a low-pressure offline long bag pulse bag filter. This embodiment does not limit this.

[0132] like Figure 1 As shown, before purification, the flue gas enters the ash hopper of each chamber through the flue gas inlet pipe 210 and the guide plate to make the air volume uniform. The flue gas then enters the ash hopper of each chamber through the air inlet regulating valve. Coarse dust particles settle to the bottom of the ash hopper, while fine dust particles turn upward with the airflow and enter the filter chamber. The dust is trapped on the surface of the filter bag 250. The purified flue gas enters the clean chamber through the filter bag opening and is discharged through the flue gas outlet pipe 220. Then, it is drawn to the chimney by the induced draft fan 240 and discharged into the atmosphere through the chimney. The ash accumulated in the ash hopper is discharged through the ash discharge pipe 230.

[0133] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for cleaning dust from a bag filter, characterized in that, Including the following steps: Detect the flue gas inlet and outlet pressures of the bag filter, as well as the frequency of the induced draft fan; The pressure differential range for stopping and starting dust removal is determined based on the frequency of the induced draft fan. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the range where cleaning is stopped, cleaning is stopped; if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure rises to the range where cleaning is started, cleaning is started. The induced draft fan is installed on the flue gas outlet pipe of the bag filter, and the upper limit of the stop cleaning pressure difference range is less than the lower limit of the start cleaning pressure difference range. The step of initiating dust removal specifically involves: starting the pulse jet module to inject gas into the filter bags of the bag filter to remove dust; The dust removal process also includes the following steps: If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the injection pressure of the injection module is controlled to be positively correlated with the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is less than the lower limit of the pressure difference range, the injection module is controlled to perform injection at the minimum injection pressure. The lower limit of the pressure difference range is the minimum pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is greater than the upper limit of the pressure difference range, the injection module is controlled to perform injection at the maximum injection pressure. The upper limit of the pressure difference range is the maximum pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure. The frequency of the induced draft fan has at least one frequency range, and the stop cleaning pressure difference range and the start cleaning pressure difference range both correspond one-to-one with the frequency range. The blowing module includes at least two blowing units arranged in sequence, and any two blowing units are used to blow gas onto different filter bags; each blowing unit is connected to a gas source through a gas supply branch pipe, and a regulating valve is provided on the gas supply branch pipe. The steps to initiate the dust removal process specifically include the following steps: First, control the first-ordered pulse-jet unit to pulse. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the first-ordered pulse-jet unit has been pulsed for a set time, then control the second-ordered pulse-jet unit to pulse.

2. The dust removal method according to claim 1, characterized in that, There are at least two frequency intervals, and no two frequency intervals overlap. The upper limit of the differential pressure range for stopping dust cleaning and the lower limit of the differential pressure range for starting dust cleaning are both positively correlated with the upper limit of the frequency range.

3. The dust removal method according to claim 1, characterized in that, At the same frequency of the induced draft fan, the determined range of the stop cleaning pressure difference is less than the first set value, the obtained range of the start cleaning pressure difference is greater than the second set value, and the first set value is less than the second set value.

4. The dust removal method according to any one of claims 1-3, characterized in that, If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the blowing pressure of the blowing module is controlled to have a linear relationship with the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure.

5. The dust removal method according to any one of claims 1-3, characterized in that, The filter bags in the bag filter are divided into a first filter bag group and a second filter bag group. The first filter bag group is close to the flue gas inlet of the bag filter, and the second filter bag group is far away from the flue gas inlet of the bag filter. The blowing module includes at least two blowing units. All the blowing units are divided into a first blowing unit that blows the first filter bag group and a second blowing unit that blows the second filter bag group. The blowing nozzle of the first blowing unit is larger than the blowing nozzle of the second blowing unit.

6. A dust removal device for a bag filter, characterized in that, include: The first detector is used to detect the flue gas inlet pipe pressure of the bag filter; The second detector is used to detect the flue gas outlet pressure of the bag filter; The third detector is used to detect the frequency of the induced draft fan; The determining module is used to determine the stop cleaning pressure differential range and the start cleaning pressure differential range based on the frequency of the induced draft fan; The dust removal module is used to clean the accumulated dust on the filter bags in the bag filter. The first control module controls the cleaning module to stop cleaning if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure drops to the stop cleaning pressure difference range; and controls the cleaning module to start cleaning if the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure rises to the start cleaning pressure difference range. The induced draft fan is installed on the flue gas outlet pipe, and the upper limit of the stop cleaning pressure differential range is less than the lower limit of the start cleaning pressure differential range. The dust removal module is a jetting module used to blow gas into the filter bag for dust removal; The dust removal device of the bag filter also includes a second control module; If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the second control module is used to control the injection pressure of the injection module to be positively correlated with the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is less than the lower limit of the pressure difference range, the second control module is used to control the injection module to perform injection at the minimum injection pressure, where the lower limit of the pressure difference range is the minimum pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is greater than the upper limit of the pressure difference range, the second control module is used to control the injection module to perform injection at the maximum injection pressure, where the upper limit of the pressure difference range is the maximum pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure. The determining module includes: a storage unit for storing the frequency of the induced draft fan, and the corresponding stop cleaning pressure differential range and start cleaning pressure differential range at the frequency of the induced draft fan; and an acquisition unit for acquiring the stop cleaning pressure differential range and start cleaning pressure differential range from the storage unit according to the frequency of the induced draft fan. The storage unit stores the frequency of the induced draft fan in the form of frequency intervals, and there is at least one frequency interval. The stop cleaning pressure difference range and the start cleaning pressure difference range are both one-to-one correspondences with the frequency intervals. The blowing module includes at least two blowing units arranged in sequence, and any two blowing units are used to blow gas onto different filter bags; each blowing unit is connected to a gas source through a gas supply branch pipe, and a regulating valve is provided on the gas supply branch pipe. The first control module is used to first control the first ranked pulse-jet unit to pulse. If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure does not drop to the stop cleaning pressure difference range after the first ranked pulse-jet unit has been pulsed for a set time, then the second ranked pulse-jet unit will be controlled to pulse.

7. The dust removal device according to claim 6, characterized in that, There are at least two frequency intervals, and no two frequency intervals overlap. The upper limit of the differential pressure range for stopping dust cleaning and the lower limit of the differential pressure range for starting dust cleaning are both positively correlated with the upper limit of the frequency range.

8. The dust removal device according to claim 6, characterized in that, At the same frequency of the induced draft fan, the range of pressure difference for stopping dust removal determined by the determining module is less than a first set value, and the range of pressure difference for starting dust removal determined by the determining module is greater than a second set value, wherein the first set value is less than the second set value.

9. The dust removal device according to any one of claims 6-8, characterized in that, If the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure is within the pressure difference range, the second control module is used to control the injection pressure of the injection module to be linearly related to the pressure difference between the flue gas inlet pipe pressure and the flue gas outlet pipe pressure.

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