Anti-blocking method for air preheater

Abstract

The invention discloses an anti-blocking method for an air preheater. The anti-blocking method comprises the steps that S100, the front-back pressure difference of the smoke side of the air preheater is obtained; s200, when the pressure difference is larger than a first preset value and lasts for at least a first preset duration, the unit is controlled to conduct soot blowing through a low-frequency high-sound-intensity sound wave soot blower; after the unit blows soot through the low-frequency high-sound-intensity sound wave soot blower for a first preset number of times, the pressure difference is detected, if the pressure difference is larger than a second preset value and lasts for at least a second preset duration, it is determined that blockages mainly containing ammonium bisulfate appear in the air preheater, pyrolysis operation is executed, and the second preset value is larger than the first preset value. The frequency of pyrolyzing ammonium bisulfate can be reduced, the service life of each part of the unit is prolonged, the operation stability of the unit is improved, and maintenance suggestions are provided for frequently accumulated ammonium bisulfate.

Description

Technical Field

[0001] The invention relates to the technical field of air preheaters, and in particular to an anti-blocking method for air preheaters. Background Art

[0002] With the increase in the operating time of the SCR reactor and the increase in the amount of ammonia injection after ultra-low emissions, the equipment and pipelines downstream of the SCR have experienced varying degrees of blockage, corrosion, and increased resistance. Among them, the problem of ash accumulation and blockage in the air preheater is particularly serious. The substances that cause ash accumulation and blockage in the air preheater are mainly flue gas dust, ammonium bisulfate, ammonium sulfate and other substances. Based on the fact that ammonium bisulfate can be pyrolyzed at a certain temperature, when the pressure difference of the air preheater reaches the set value, the unit will be controlled to perform the ammonium bisulfate pyrolysis operation, thereby solving the problem of air preheater blockage. However, frequent pyrolysis operations will affect the normal operation of the unit on the one hand, and on the other hand, since the pyrolysis process of ammonium bisulfate requires precise control of temperature and concentration, improper operation may cause equipment damage or affect the life of the equipment.

[0003] Based on this, how to avoid frequent thermal decomposition of ammonium bisulfate while preventing air preheater blockage, thereby increasing the life of unit components and the stability of unit power supply, is a difficult problem that urgently needs to be solved in the current air preheater blockage. Summary of the invention

[0004] The object of the present invention is to provide an anti-clogging method for an air preheater to solve the problems raised in the above background technology.

[0005] In one aspect, the present invention provides an anti-clogging method for an air preheater, comprising the following steps:

[0006] Step S100, obtaining the pressure difference before and after the flue gas side of the air preheater;

[0007] Step S200, when the pressure difference is greater than a first preset value and lasts for at least a first preset time, the unit is controlled to perform soot blowing with a low-frequency and high-intensity soot blower; after the unit performs soot blowing with a low-frequency and high-intensity soot blower for a first preset number of times, the pressure difference is detected. If the pressure difference is greater than a second preset value and lasts for at least a second preset time, it is determined that the air preheater is blocked by ammonium bisulfate, and a pyrolysis operation is performed, wherein the second preset value is greater than the first preset value.

[0008] Optionally, the control unit performs the pyrolysis operation by raising the outlet temperature of the air preheater to T1 and maintaining it for a third preset time period, and raising the average inlet temperature of the electrostatic precipitator corresponding to the air preheater to T2 and maintaining it for a fourth preset time period.

[0009] Optionally, T1 is 160° C., the third preset time is 4 hours, T2 is 160° C., and the fourth preset time is 20 hours.

[0010] Optionally, the first preset number of times is 3.

[0011] Optionally, it also includes: counting the number of pyrolysis actions, if the number of pyrolysis actions exceeds a second preset number, the user is sent a prompt message, the prompt message content includes replacing the catalyst of the selective catalytic reduction SCR reactor and modifying the ammonia injection grid.

[0012] Optionally, the reforming of the ammonia injection grid includes: simulating and calculating the resistance from the deoxidized ammonia injection pipe to the injection hole of the selective catalytic reduction SCR reactor, and adjusting the number of openings of each ammonia injection pipe according to the calculation result.

[0013] Optionally, the method of sending prompt information to the user includes: sending the prompt information to the user through a smart terminal.

[0014] Optionally, the second preset number is 2.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. After the unit performs soot blowing with a low-frequency, high-intensity sootblower for a first preset number of times, the pressure difference is detected. If the pressure difference is greater than a second preset value and lasts for at least a second preset time, it is determined that the air preheater is blocked by ammonium bisulfate, and a pyrolysis operation is performed, wherein the second preset value is greater than the first preset value. On the one hand, it can be confirmed that the air preheater is blocked by ammonium bisulfate as the main cause, and on the other hand, the frequency of ammonium bisulfate pyrolysis operations can be reduced, thereby increasing the life of the generator set and ensuring the stability of the power supply unit.

[0017] 2. By counting the number of pyrolysis operations, if the number of pyrolysis operations exceeds the second preset number, the user is sent a prompt message, which includes replacing the catalyst of the selective catalytic reduction SCR reactor and modifying the ammonia injection grid. It can provide the cause of the frequent generation of ammonium bisulfate in the user's air preheater and provide the user with a fault handling solution to improve the user experience.

[0018] 3. Eliminate the ammonium bisulfate blockage in the air preheater through specific pyrolysis operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A flow chart of an anti-clogging method for an air preheater according to the present invention;

[0020] Figure 2 The present invention is an air preheater ammonium bisulfate pyrolysis operation flow chart. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Figure 1 FIG. 1 is a flow chart of an anti-clogging method for an air preheater according to an embodiment of the present invention. Figure 1 As shown, an embodiment of the present invention provides an anti-clogging method for an air preheater.

[0023] The anti-clogging method of the air preheater comprises the following steps:

[0024] Step S100, obtaining the pressure difference before and after the flue gas side of the air preheater;

[0025] Step S200, when the pressure difference is greater than a first preset value and lasts for at least a first preset time, the unit is controlled to perform soot blowing with a low-frequency and high-intensity soot blower; after the unit performs soot blowing with a low-frequency and high-intensity soot blower for a first preset number of times, the pressure difference is detected. If the pressure difference is greater than a second preset value and lasts for at least a second preset time, it is determined that ammonium bisulfate is blocked in the air preheater, and a pyrolysis operation is performed, wherein the second preset value is greater than the first preset value.

[0026] In this embodiment, each unit is equipped with two air preheaters, each unit is modified to be equipped with a selective catalytic reduction SCR reactor, and wind pressure sensors or pressure difference sensors are respectively provided on the flue gas paths at the inlet and outlet of the air preheater; the pressure difference before and after the flue gas side of the air preheater refers to the pressure difference between the inlet and outlet flue gas paths of the air preheater, which is a key indicator for judging the operation of the air preheater. A low-frequency and high-intensity sonic soot blower is installed at the inlet of the flue gas side of the air preheater. When the pressure difference is greater than the first preset value and lasts for at least the first preset time, it means that there is a blockage problem in the air preheater, then the low-frequency and high-intensity sonic soot blower is controlled to work, and the loose scale on the surface of the air preheater is removed by means of sound wave vibration. In this case, the loose scale on the surface of the air preheater is generally ammonium sulfate and dust, and the amount of ammonium bisulfate is relatively small. When the injected ammonia cannot fully participate in the selective catalytic reduction (SCR) reaction, the escaped ammonia is easy to react with SO3 in the flue gas to generate ammonium sulfate and ammonium bisulfate. The amount of ammonium bisulfate generated is proportional to the content of ammonia and SO3 in the flue gas. Ammonium sulfate is a dry powdered solid that is not corrosive and can be easily removed by soot blowing, while ammonium bisulfate is very viscous and will accumulate on the surface of objects in liquid form. The cold end operating temperature of the air preheater of the power plant generator set is generally lower than the dew point of ammonium bisulfate, which can easily cause ammonium bisulfate to precipitate and adhere to fly ash. When the SCR ammonia spray is uneven or the catalyst is severely deactivated, the risk of ammonium bisulfate corrosion in the downstream air preheater increases. In other words, when the blockage of the air preheater is mainly ammonium sulfate, the blockage of the air preheater is relatively easy to remove. Then, the loose blockage mainly composed of ammonium sulfate can be easily removed by a low-frequency and high-intensity soot blower, reducing the pressure difference between the inlet and outlet of the air preheater and alleviating the blockage. When the SCR ammonia spray is uneven or the catalyst is seriously deactivated, or the operation time is long, the blockage of the air preheater is mainly ammonium bisulfate and its adhered fly ash. Due to the strong viscosity of ammonium bisulfate, it is still not possible to remove the blockage well by only using a low-frequency and high-intensity sonic soot blower, reduce the pressure difference between the inlet and outlet of the air preheater, and alleviate the blockage. At this time, it is necessary to perform an ammonium bisulfate pyrolysis operation to remove the blockage mainly composed of ammonium bisulfate. If the air preheater is blocked and the blockage is directly removed by pyrolysis instead of acoustic vibration, the pyrolysis operation will be performed frequently. The pyrolysis of ammonium bisulfate requires adjustment of the unit load, fan speed, temperature rise and other operations. If you are not careful, it will affect the life of related components such as the air preheater, induced draft fan, and components in the desulfurization absorption tower. Based on this, in order to reduce the frequency of ammonium bisulfate pyrolysis operations, improve the life of the generator set, and ensure the stability of the power supply unit, the present invention first performs a first preset number of low-frequency and high-intensity soot blowing with a soot blower when it is determined that the air preheater is blocked; after the unit performs the first preset number of low-frequency and high-intensity soot blowing with a soot blower, if blockage still exists and the blockage becomes more serious, it means that the current blockage is mainly ammonium bisulfate and a pyrolysis operation needs to be performed.The low-frequency and high-intensity sonic soot blower runs for 1 hour or a set duration each time. The specific duration is set based on experience. The blockage in the air preheater is removed through sonic vibration and soot blowing.

[0027] The blockages of air preheaters usually include ammonium sulfate, dust, and ammonium bisulfate. Ammonium sulfate or dust blockage means that the blockage of the air preheater is mainly caused by ammonium sulfate or dust, and ammonium bisulfate blockage means that the blockage of the air preheater is mainly caused by ammonium bisulfate and its attached dust. Of course, it can be distinguished by the proportion of ammonium sulfate or ammonium bisulfate in the total of ammonium sulfate and ammonium bisulfate in the blockage of the air preheater. For example, ammonium sulfate blockage means that ammonium sulfate accounts for 70% of the total of ammonium sulfate and ammonium bisulfate in the blockage of the air preheater, and ammonium bisulfate blockage means that ammonium bisulfate accounts for 40% of the total of ammonium sulfate and ammonium bisulfate in the blockage of the air preheater. This is because ammonium bisulfate will stick together with dust. Although the proportion of ammonium bisulfate is low, serious blockage will still occur. Therefore, when the actual proportion of ammonium bisulfate is low, the total blockage after ammonium bisulfate and dust are bonded is relatively high, and blockage will also occur. Of course, the specific proportions can also be set according to actual conditions. For example, ammonium sulfate blockage means that ammonium sulfate accounts for 65% of the total of ammonium sulfate and ammonium bisulfate, which are blockages in the air preheater, or other ratios. Ammonium bisulfate blockage means that ammonium bisulfate accounts for 35% or other ratios of the total of ammonium sulfate and ammonium bisulfate, which are blockages in the air preheater. Dust blockage means that dust accounts for the main proportion of the blockage in the air preheater, such as 70%. Dust and ammonium sulfate blockage means that ammonium sulfate and dust account for the main proportion of the blockage in the air preheater, such as 70%. The above-mentioned proportion values ​​can be set specifically based on experience and will not be repeated here.

[0028] Blockages caused mainly by ammonium sulfate or dust can be cleared by sonic vibration and soot blowing. However, for ammonium bisulfate blockage, due to the strong adhesion of ammonium bisulfate, the effect of clearing by sonic vibration and soot blowing alone is poor. Therefore, it is necessary to clear it through the thermal decomposition of ammonium bisulfate.

[0029] Furthermore, the control unit performs the pyrolysis operation by raising the outlet temperature of the air preheater to T1 and maintaining it for a third preset time, and raising the average inlet temperature of the electrostatic precipitator corresponding to the air preheater to T2 and maintaining it for a fourth preset time.

[0030] Because the melting point of ammonium bisulfate is 147°C, when the outlet temperature of the air preheater is higher than 147°C, the ammonium bisulfate begins to become liquid and is easy to remove. T1 is greater than 147°C, preferably 160°C, and the third preset time is preferably 4h. T2 is greater than 147°C, preferably 160°C, and the fourth preset time is preferably 20h.

[0031] Figure 2 The present invention is a flowchart of the operation of pyrolysis of ammonium bisulfate in an air preheater according to an embodiment of the present invention.

[0032] The pyrolysis operation comprises:

[0033] Step S301, exit the following interlock protection:

[0034] The air preheater outlet temperature is 185℃, and the corresponding side induced draft fan interlock is tripped.

[0035] Air preheater shutdown interlocking of the air preheater inlet and outlet air and smoke dampers,

[0036] The air preheater stops and trips the supply fan, induced draft fan, and primary fan interlocks.

[0037] The flue gas temperature at the absorption tower inlet is 155℃ and the boiler main fuel trips the MFT interlock;

[0038] Step S302, close the air preheater inlet and outlet smoke dampers, i.e., adjust the position;

[0039] Step S303, set the boiler air and smoke system primary air, supply air, and induced draft fan communication dampers to "no operation", and keep the communication dampers in the open state;

[0040] Step S304, gradually and slowly close the first and second air dampers at the outlet of the air preheater, control the temperature rise to no more than 3°C / min when the exhaust temperature is below 150°C, and the temperature rise rate to less than 1°C / min when the exhaust temperature is above 150°C, and slowly close the second and second air dampers at the outlet of the air preheater according to the outlet temperature of the air preheater, open the secondary air door in time when closing the second and second air dampers at the outlet of the air preheater, control the outlet pressure of the blower to no more than 2.7KPa, and prevent the blower from surging;

[0041] Step S305, continuously blowing soot on the air preheater during the heating process of the air preheater;

[0042] Step S306, when the current fluctuation of the air preheater exceeds 10A or the current reaches 60A, the temperature rise is stopped, and when the current fluctuation is less than 5A and the current is less than 50A, the temperature rise is continued;

[0043] Step S307, when the exhaust temperature of the air preheater reaches 160°C, monitor the change of the air preheater differential pressure. When the differential pressure drops, the flue gas volume will increase, and the exhaust temperature will slowly increase automatically. Slowly open a secondary air door at the outlet of the air preheater on this side to a certain degree to increase the secondary air volume and control the exhaust temperature to continue to rise;

[0044] Step S308, monitor the flue gas temperature at the dust collector inlet and the original flue gas temperature at the desulfurization inlet corresponding to the air preheater, and start the emergency spray when the temperature reaches 150°C.

[0045] Step S309: When the differential pressure does not decrease within 15 minutes, the thermal decomposition of ammonium bisulfate in the air preheater is completed.

[0046] Specifically, there are two sets of SCR reactors and fan systems connected to the boiler, which we call side A and side B for the convenience of explanation. On side A, the flue gas output of the boiler is connected to the SCR reactor on side A, and the output of the SCR reactor on side A is connected to the air preheater on side A. The air preheater on side A can be divided into three parts, including the primary air side on side A, the flue gas side on the heating side, and the secondary air side on side A. The connection between the induced draft fan on side A and the flue gas side of the air preheater on side A is used to take away the heat of the flue gas and the air preheater, and the connection between the blower on side A and the secondary air side of the air preheater on side A is used to cool the air preheater on side A and increase the oxygen content of the boiler. This invention is mainly aimed at thermal decomposition of ammonium bisulfate in one set of air preheaters.

[0047] Specifically, the online heating pyrolysis for a #3 unit is as follows:

[0048] 1. Operation mode before pyrolysis

[0049] #3 unit coordinated control mode, heat load 530MW, C, D, E, F coal mills in operation, six large fans in operation, denitrification system and desulfurization system in operation normally.

[0050] 2. Pyrolysis Operation Process

[0051] On February 9, 2024, at 10:00, the heat load of unit #3 was 530MW, and the 3B air preheater online heating pyrolysis plan was implemented. The preparation work is as follows:

[0052] 1. Exit the following interlock protection:

[0053] 3B air preheater outlet temperature ≥185℃, 3B induced draft fan will be tripped;

[0054] 3B air preheater shuts down and trips 3B supply fan, 3B induced draft fan and 3B primary fan;

[0055] When the flue gas temperature at the inlet of No. 3 desulfurization absorption tower is ≥155℃, FGD trips and triggers MFT.

[0056] 2. Adjust the outlet secondary air damper and inlet flue gas damper of 3B air preheater to the "small hand" (debugging position).

[0057] 3. Set the #3 furnace air and smoke system primary air, supply air, and induced draft fan communication dampers to “No Operation” and keep the communication dampers open.

[0058] 4. Set the outlet secondary air damper, inlet flue gas damper, and inlet and outlet primary air dampers of the 3B air preheater to “No Operation”.

[0059] 5. Gradually turn on both blowers to recirculate hot air.

[0060] 6. The emergency spraying of the trial #3 absorption tower was normal.

[0061] At 11:00, the secondary air damper at the outlet A of the 3B air preheater was gradually closed manually, by 10% each time, until it was completely closed. No obvious changes were observed in the exhaust gas temperature at the outlets of the 3A and 3B air preheaters, the outlet air pressure of the blower, and the secondary air box pressure. 3B was then gradually closed manually on site;

[0062] The secondary air damper at the air preheater outlet B was opened and closed by 10% at a time, and then closed to 50% and paused. It was observed that there were still no obvious changes in the exhaust gas temperature at the 3A and 3B air preheater outlets, the air pressure at the blower outlet, and the secondary air box pressure.

[0063] At 11:00, during the heating process of the 3B air preheater, the sootblower was contacted in advance to increase the sootblowing pressure setting value of the air preheater to 2.2MPa, and the 3B air preheater was put into continuous sootblowing (the sootblowing gun of the 3A air preheater was shielded).

[0064] At 11:30, the secondary air damper at outlet B of 3B air preheater continued to be manually closed on site, with an amplitude of 5% each time. During the process of the opening of the secondary air damper at outlet B of 3B air preheater increasing from 40% to 30%, the air pressure at the blower outlet increased from 1.9KPa to 2.6KPa, and the secondary air flow rate at outlet B side of 3B air preheater decreased from 950t / h to 770t / h, and the secondary air flow rate at outlet A side of 3A air preheater increased from 1000t / h to 1200t / h. Due to the obvious changes in parameters, the operating amplitude of the secondary air damper at outlet B of 3B air preheater was slowed down, with an operation amplitude of 3% each time.

[0065] At 12:00, the secondary air damper B at the outlet of 3B air preheater was closed to about 14%, and the exhaust gas temperature at the outlet of 3B air preheater rose to 150℃. The exhaust gas temperature at the outlet of 3A air preheater dropped to 92℃. The inlet temperature of the electrostatic precipitator on the B side rose to about 140℃. The original flue gas temperature of the #3 desulfurization absorption tower rose to about 110℃.

[0066] At 12:30, the secondary air damper B at the outlet of 3B air preheater was closed to about 12%, and the exhaust gas temperature at the outlet of 3B air preheater rose to 160℃. The exhaust gas temperature at the outlet of 3A air preheater dropped to 92℃. The inlet temperature of the electrostatic precipitator on the B side rose to about 150℃. The original flue gas temperature of the #3 desulfurization absorption tower rose to about 120℃.

[0067] At 13:00, the secondary air damper B at the outlet of the 3B air preheater was closed to about 10%, and the exhaust gas temperature at the outlet of the 3B air preheater rose to 168°C. The exhaust gas temperature at the outlet of the 3A air preheater dropped to 85°C.

[0068] The inlet temperature of the electrostatic precipitator on the B side rose to about 155°C. The original flue gas temperature of the #3 desulfurization absorption tower rose to about 127°C.

[0069] At 17:30, unit #3 was ready to add load, and personnel were arranged in advance to wait on site to open the secondary air damper B at the outlet of the 3B air preheater to control the exhaust gas temperature at the outlet of the 3B air preheater.

[0070] At 18:10, the heat load of unit #3 was increased to 630MW, and the secondary air damper B at the outlet of the 3B air preheater was slowly opened to about 18%, and the exhaust gas temperature at the outlet of the 3B air preheater was controlled to be stable at about 167°C. The inlet temperature of the electrostatic precipitator on the B side was about 155°C. The original flue gas temperature of the #3 desulfurization absorption tower was about 127°C.

[0071] At 23:45, the heat load of unit #3 dropped to 530MW, and the secondary air damper B at the outlet of 3B air preheater was slowly closed to about 10%, and the exhaust gas temperature at the outlet of 3B air preheater was controlled to be stable at 167℃. The exhaust gas temperature at the outlet of 3A air preheater dropped to 80℃.

[0072] At 01:20 on February 10, 2024, the heat load of unit #3 dropped to 465MW, and the flue gas temperature at the outlet of the 3B air preheater finally stabilized to 155°C. The flue gas temperature at the outlet of the 3A air preheater finally stabilized to 77°C.

[0073] 07:45 The heat load of unit #3 was increased to 820MW. The secondary air damper B at the outlet of the 3B air preheater was slowly opened to about 40%, and the exhaust gas temperature at the outlet of the 3B air preheater was controlled to be stable at about 165℃. The inlet temperature of the electrostatic precipitator on the B side was about 155℃. The original flue gas temperature of the #3 desulfurization absorption tower was about 127℃.

[0074] At 10:00, the pyrolysis work of the 3B air preheater was completed, and the hot secondary air dampers A and B of the 3B air preheater outlet were slowly opened on site. After the air and smoke of the air preheater were leveled, the thermal engineer was contacted to restore the exit interlock and protection during the online heating and pyrolysis work of the 3B air preheater. The sootblower was contacted to restore the sootblowing pressure setting value of the #3 furnace air preheater to 1.5MPa.

[0075] 2024.02.1109:00, close the #3 furnace air and smoke system supply, exhaust and primary fan communication damper, observe that the parameters of the #3 furnace air and smoke system have no changes, and reopen the #3 furnace air and smoke system supply, exhaust and primary fan communication damper.

[0076] 5. Changes of parameters before and after pyrolysis of 3B air preheater (heat load of #3 boiler 950MW)

[0077]

[0078] Furthermore, the first preset number of times is 3.

[0079] Furthermore, it also includes: counting the number of pyrolysis operations, if the number of pyrolysis operations exceeds a second preset number, the user is sent a prompt message, the prompt message content includes replacing the catalyst of the selective catalytic reduction SCR reactor and modifying the ammonia injection grid.

[0080] When the number of pyrolysis operations exceeds the second preset number, it indicates that ammonium bisulfate is the main cause of the blockage of the air preheater, and the reason for the frequent excess of ammonium bisulfate is the ammonia escape amount, and the reason for the increase in ammonia escape amount is uneven flow field distribution, poor adjustment of the ammonia injection grid, and catalyst aging, etc. The second preset number is preferably 2.

[0081] Furthermore, the reforming of the ammonia injection grid includes: simulating and calculating the resistance from the deoxidized ammonia injection pipe to the injection hole of the selective catalytic reduction SCR reactor, and adjusting the number of openings of each ammonia injection pipe according to the calculation result.

[0082] The simulation calculation can be performed using FLunt software or CFD software to determine the resistance from the SCR ammonia injection pipe to the spray hole through simulation, and then adjust the number of openings in each ammonia injection pipe to reduce the resistance of the dilution air system and reduce the amount of ammonia escape.

[0083] The method of "sending prompt information to the user" includes: sending prompt information to the user through a smart terminal, and the smart terminal includes a smart phone; for example, sending prompt information to an APP on the smart phone.

[0084] The present invention sends prompt information to the user, so that the user can know the specific cause of the blockage of the air preheater and the rectification method in time, thereby improving the stability of the unit operation.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0086] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0087] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0088] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or otherwise processing in a suitable manner if necessary, and then stored in a computer memory.

[0089] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0090] A person skilled in the art may understand that all or part of the steps in the above-mentioned embodiment method may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0091] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0092] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for preventing clogging of an air preheater, The following steps are involved: Step S100, obtaining the pressure difference before and after the flue gas side of the air preheater; Step S200, when the pressure difference is greater than a first preset value and lasts for at least a first preset time, the unit is controlled to perform soot blowing with a low-frequency and high-intensity soot blower; after the unit performs soot blowing with a low-frequency and high-intensity soot blower for a first preset number of times, the pressure difference is detected. If the pressure difference is greater than a second preset value and lasts for at least a second preset time, it is determined that ammonium bisulfate is blocked in the air preheater, and a pyrolysis operation is performed, wherein the second preset value is greater than the first preset value.

2. The anti-clogging method for an air preheater according to claim 1, Features: The control unit performs the pyrolysis operation by raising the outlet temperature of the air preheater to T1 and maintaining it for a third preset time, and raising the average inlet temperature of the electrostatic precipitator corresponding to the air preheater to T2 and maintaining it for a fourth preset time.

3. The anti-clogging method for an air preheater according to claim 2, Features: T1 is 160° C., the third preset time is 4 hours, T2 is 160° C., and the fourth preset time is 20 hours.

4. The anti-clogging method for an air preheater according to claim 1, Features: The first preset number is 3.

5. The anti-clogging method for an air preheater according to claim 1, Features: Also includes: The number of pyrolysis actions is counted. If the number of pyrolysis actions exceeds a second preset number, a prompt message is sent to the user. The prompt message includes replacing the catalyst of the selective catalytic reduction SCR reactor and modifying the ammonia injection grid.

6. The anti-clogging method for an air preheater according to claim 5, Features: The reforming of the ammonia injection grid includes: simulating and calculating the resistance from the deoxidized ammonia injection pipe to the injection hole of the selective catalytic reduction (SCR) reactor, and adjusting the number of openings of each ammonia injection pipe according to the calculation result.

7. The anti-clogging method for an air preheater according to claim 5, Features: The method for sending prompt information to a user includes: sending prompt information to the user via a smart terminal.

8. The anti-clogging method for an air preheater according to claim 5, Features: The second preset number is 2.

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