CN114367195A - SCR denitration ammonia-spraying grid online ash blocking prevention purging system and fault diagnosis method - Google Patents

SCR denitration ammonia-spraying grid online ash blocking prevention purging system and fault diagnosis method Download PDF

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CN114367195A
CN114367195A CN202111550396.3A CN202111550396A CN114367195A CN 114367195 A CN114367195 A CN 114367195A CN 202111550396 A CN202111550396 A CN 202111550396A CN 114367195 A CN114367195 A CN 114367195A
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aig
flow
ammonia
branch pipe
compressed air
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金理鹏
赵俊武
周健
韦振祖
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Xian Thermal Power Research Institute Co Ltd
Suzhou Xire Energy Saving Environmental Protection Technology Co Ltd
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Xian Thermal Power Research Institute Co Ltd
Suzhou Xire Energy Saving Environmental Protection Technology Co Ltd
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Abstract

The invention provides an SCR denitration ammonia injection grid online ash blockage prevention purging system and a fault diagnosis method, which can solve the problem that the safe and stable operation of an SCR denitration device is influenced because the problems of AIG nozzle blockage, ammonia injection branch pipeline abrasion and the like cannot be diagnosed in real time in the existing SCR denitration operation. The method judges whether the nozzles of the AIG branch pipes and the AIG branch pipes have faults or not by detecting the flow of real-time ammonia gas-air mixed gas in each AIG branch pipe in real time through the arranged ammonia spraying flow online measurement control device, particularly through the throttle orifice plates arranged on each path of AIG branch pipes, the local pressure difference meter and the flow transmitter, and controls the compressed air purging device to perform timely purging operation or cut off the air spraying flow channels of the AIG branch pipes with faults according to the judgment result, so that the method can effectively and actively monitor and diagnose the faults, avoid the faulty operation of equipment and improve the safety of SCR denitration operation.

Description

SCR denitration ammonia-spraying grid online ash blocking prevention purging system and fault diagnosis method
Technical Field
The invention relates to the field of SCR flue gas denitration treatment of coal-fired boilers, in particular to an SCR denitration ammonia-spraying grid online ash blockage prevention purging system and a fault diagnosis method.
Background
The SCR flue gas denitration technology is the most widely applied, mature and reliable denitration technology of the current coal-fired boiler, wherein an SCR denitration ammonia injection mixing system (AIG) is the key influencing the SCR denitration operation performance. At present, multiple branches of an SCR (Selective catalytic reduction) generally adopt a multi-nozzle AIG (air in air) ammonia injection grid with transversely and longitudinally adjustable nozzles, in SCR denitration operation, ammonia air mixed gas is injected into an SCR inlet flue through each branch pipeline of the AIG and the nozzles on each branch pipeline to be fully mixed with flue gas, and the nozzles are uniformly arranged on the cross section of the flue, so that NH (ammonia) in the SCR inlet flue is ensured3The distribution uniformity of the/NOx molar ratio is improved, so that the safe and economic operation of the SCR denitration device is improved.
The problems of AIG nozzle blockage, ammonia injection branch pipeline abrasion and the like frequently occur in SCR denitration operation, but the problems are difficult to find in time in the SCR denitration operation process at present and can only be found in the process of machine group shutdown or operation overhaul personnel inspection. Once such nozzle blockage and branch pipeline abrasion occur in SCR denitration operation, the uniformity of ammonia spraying mixing of the structure in an SCR inlet flue can be seriously damaged, local under-spraying ammonia on the cross section and local excessive ammonia spraying are easily caused, further, the local ammonia escape concentration at the outlet of an SCR reactor exceeds the standard, the SCR denitration performance is reduced, and further, the ABS (anti-lock brake system) of a unit air preheater is blocked, so that the safety, stability, economic operation and safe and stable operation of the unit are seriously influenced.
Disclosure of Invention
Aiming at the problems, the invention provides an SCR denitration ammonia injection grid online ash blockage prevention purging system and a fault diagnosis method, which can solve the problem that the safe and stable operation of an SCR denitration device is influenced because the problems of AIG nozzle blockage, ammonia injection branch pipeline abrasion and the like cannot be diagnosed in real time in the existing SCR denitration operation.
SCR denitration ammonia injection grid's stifled sweep system of online ash prevention, it is including leading to the female pipe of air feed that has ammonia air mist, parallelly connected has a plurality of AIG branch pipes on the female pipe of air feed, every the AIG branch pipe all communicates to SCR reactor entry flue through the ammonia injection grid that connects separately in, its characterized in that: the compressed air blowing device comprises a compressed air tank, a compressed air conveying main pipe and a compressed air blowing pipeline, wherein the compressed air conveying main pipe is connected with the compressed air tank, one compressed air blowing pipeline capable of being connected or blocked in real time is arranged between each AIG branch pipe and the compressed air conveying main pipe, and each AIG branch pipe is also provided with a group of ammonia blowing flow online measurement control devices connected with a unit DCS control system through signals; the ammonia injection flow online measurement control device comprises a pneumatic shutoff valve and a flow monitoring assembly which are arranged on AIG branch pipes, wherein the flow monitoring assembly comprises a throttle orifice plate, an on-site differential pressure gauge and a flow transmitter; the on-site pressure difference meter and the flow transmitter of each group of the on-line measuring and controlling device are in signal connection with the unit DCS control system, and the unit DCS control system can calculate the actual flow of the ammonia-air mixed gas in each AIG branch pipe in real time according to the received on-site pressure difference meter signal and flow transmitter signal data of the flow monitoring assembly on each AIG branch pipe and judge whether the nozzle is blocked or the pipeline is abraded on the AIG branch pipe according to the actual flow.
Furthermore, each compressed air purging pipeline is provided with a compressed air purging valve.
Furthermore, a compressed air local pressure gauge and a pressure transmitter are arranged on the compressed air conveying main pipe and on the first path and on the front side of the compressed air purging pipeline.
SCR denitration ammonia injection gridThe online fault diagnosis method is characterized in that: the ammonia gas and air mixed gas in the mixed gas main pipe in SCR denitration operation is sent into an inlet flue of an SCR reactor through each AIG branch pipe and an ammonia spraying grid thereof, and the actual flow Q 'of the ammonia gas and air mixed gas in each AIG is monitored in real time by the DCS of the unit through the online ammonia spraying flow measuring and controlling device arranged on each AIG branch pipe'vIf the actual flow rate is Q'vWhen the flow rate of the mixed gas is within the preset effective mixed gas flow threshold range, all the AIG branch pipes and the ammonia spraying grids thereof are in a normal working state, and the compressed air purging pipelines on the AIG branch pipes in the normal working state are always in a normally-off state; if the actual flow Q 'of the ammonia gas-air mixed gas in any AIG branch pipe'vAnd if the flow rate of the mixed gas exceeds the preset effective mixed gas flow rate threshold range, the AIG branch pipe or the ammonia spraying grid of the AIG branch pipe fails, and the unit DCS control system sends alarm information.
Furthermore, the actual flow Q 'of the ammonia-air mixed gas in each AIG branch pipe'vThe calculation is performed according to the following formula (1):
Figure BDA0003417018290000021
in the formula (1), the first and second groups,
Q'vactual ammonia-air mixture flow per AIG branch line (unit m)3/h)；
K is the coefficient;
d, measuring the opening diameter (unit mm) of a throttle orifice of the control device on line by the ammonia spraying flow;
ε -coefficient of dielectric expansion;
alpha is the flow coefficient;
Δ P-orifice differential pressure (in Pa);
rho-density of ammonia-air mixture gas (unit kg/m)3)。
Furthermore, the unit DCS control system presets the effective mixed gas flow threshold range in each AIG branch pipe to be Qvmin≤Q'v≤QvmaxWherein Q isvmaxFor maximum mixed gas in each AIG branch pipeControlling the flow rate, QvminThe minimum control flow of the mixed gas in each AIG branch pipe is provided.
Furthermore, the maximum control flow Q of the mixed gas in each AIG branch pipevmaxMinimum control flow QvminIs determined by firstly diluting the air flow Q according to a single reactorDilution windThe conversion volume flow Q of the ammonia injection amount of a single reactorNH3To calculate the flow rate of the ammonia-air mixture gas of each AIG branch pipe
Figure BDA0003417018290000031
Where n is the number of AIG branches, Qv、QDilution wind、QNH3All units of (are m)3H; then according to the obtained QvDetermining the maximum ammonia injection amount and the minimum ammonia injection amount of the SCR reactor according to the denitration design specification and the design operation condition, and determining the maximum control flow Q of the mixed gas in each AIG branch pipe according to the maximum ammonia injection amount and the minimum ammonia injection amount of the SCR reactorvmaxAnd a minimum control flow Qvmin。
Further, when the set DCS control system monitors the actual mixed gas flow Q 'in one AIG branch pipe'vLess than minimum control flow QvminAnd when the unit DCS control system judges that the nozzles of the ammonia spraying grids of the AIG branch pipe are blocked, the unit DCS control system sends out monitoring alarm and controls the compressed air purging pipeline on the AIG branch pipe to be opened so as to purge the AIG branch pipe.
Furthermore, when the unit DCS control system controls compressed air purging on the AIG branch pipe with the nozzle blockage fault, the compressed air purging valve on the corresponding branch pipe is controlled to be opened while the pneumatic shutoff valve on the AIG branch pipe is controlled to be closed, and the end of purging or continuous purging is judged according to the compressed air purging pressure P'. Wherein, P' > P, the purging and clearing of the branch pipeline blockage is not completed; and P' < P, finishing the purging and clearing of the branch pipeline blockage. And P is the fixed value of the pressure of the compressed air pipeline determined when compressed air flows through the branch pipeline under the condition that the branch pipeline is not blocked.
Further, the method can be used for preparing a novel materialWhen the unit DCS control system monitors the actual mixed gas flow Q 'in a certain AIG branch pipe'vGreater than the maximum control flow QvmaxAnd when the machine set DCS control system judges that the AIG branch pipe has the abrasion fault, the machine set DCS control system sends out monitoring alarm.
The invention relates to an SCR denitration ammonia-spraying grid online ash blockage prevention purging system and a fault diagnosis method, which judge whether a nozzle of an AIG branch pipe and the AIG branch pipe have faults or not by detecting the flow of real-time ammonia gas-air mixed gas in each AIG branch pipe in real time through an arranged ammonia-spraying flow online measurement control device, in particular through a throttle orifice plate arranged on each path of AIG branch pipe, an in-situ pressure difference meter and a flow transmitter, and control a compressed air purging device to perform timely purging operation or cut off a gas-spraying flow passage of the AIG branch pipe with the faults according to the judgment result.
Drawings
FIG. 1 is a schematic diagram of an on-line ash blockage prevention purging system of an SCR denitration ammonia injection grid according to the invention;
fig. 2 is a flow chart of an anti-blocking purging procedure for the Px branch pipeline in the fault diagnosis method of the present invention.
Reference numerals: 10-a gas supply main pipe, 20-an AIG branch pipe, 30-an ammonia injection grid, 40-an SCR reactor inlet flue, 51-a compressed air tank, 52-a compressed air conveying main pipe, 53-a compressed air purging pipeline, 54-a compressed air purging valve, 55-a compressed air in-situ pressure gauge, 56-a pressure transmitter, 61-a pneumatic shutoff valve, 62-a throttling orifice plate, 63-an in-situ pressure difference gauge, 64-a flow transmitter and 65-a flow monitoring branch pipe.
Detailed Description
The invention provides an on-line ash blockage prevention blowing system of an SCR denitration ammonia injection grid, which is shown in figure 1, and comprises a main air supply pipe 10 filled with ammonia gas and air mixed gas, wherein a plurality of AIG branch pipes 20 are connected to the main air supply pipe 10 in parallel, and the AIG branch pipes 20 in figure 1 are P1、P2、P3、P4……Pn-1、PnNumbering in sequence, wherein each AIG branch pipe 20 is communicated to an inlet flue 40 of the SCR reactor through an ammonia injection grid 30 connected with each AIG branch pipe; the system also comprises a compressed air blowing device and an ammonia spraying flow online measurement control device, wherein the compressed air blowing device comprises a compressed air tank 51, a compressed air conveying main pipe 52 and a compressed air blowing pipeline 53, the compressed air conveying main pipe 52 is connected with the compressed air tank 51, one compressed air blowing pipeline 53 which can be connected or blocked in real time is arranged between each AIG branch pipe 20 and the compressed air conveying main pipe 52, and each AIG branch pipe 20 is also provided with a group of ammonia spraying flow online measurement control devices which are connected with a set DCS control system through signals; the ammonia injection flow online measurement control device comprises a pneumatic shutoff valve 61 and a flow monitoring assembly which are arranged on AIG branch pipes, wherein the flow monitoring assembly comprises a throttle orifice plate 62, an in-situ pressure difference meter 63 and a flow transmitter 64, each AIG branch pipe 20 is provided with the throttle orifice plate 62, two ends of the throttle orifice plate 62 are connected with a flow monitoring branch pipe 65, and the in-situ pressure difference meter 63 and the flow transmitter 64 are connected on the flow monitoring branch pipe 65 in series; the local pressure difference meter 63 and the flow transmitter 64 of each group of online measurement and control devices are in signal connection with the unit DCS control system, and the unit DCS control system can calculate the actual flow of the ammonia-air mixed gas in each AIG branch pipe 20 in real time according to the received local pressure difference meter signal 63 and the flow transmitter 64 signal data of the flow monitoring assembly on each AIG branch pipe 20 and judge whether the nozzle is blocked or the pipeline is worn or not according to the actual flow.
Each compressed air purge line 53 is provided with a compressed air purge valve 54 for controlling the connection or disconnection of the compressed air purge line 53.
The compressed air local pressure gauge 55 and the pressure transmitter 56 are arranged on the compressed air delivery main pipe 52 and in front of the first compressed air purging pipeline P1.
According to the online fault diagnosis method for the online ash blockage prevention blowing system based on the SCR denitration ammonia injection grid, ammonia gas and air mixed gas in the mixed gas main pipe passes through each AIG branch pipe 20 and each AIG branch pipe 20 in SCR denitration operationThe ammonia injection grid 30 is sent into an inlet flue 40 of the SCR reactor, and the DCS of the unit monitors the actual flow Q 'of the ammonia gas-air mixed gas in each AIG in real time through an online ammonia injection flow measurement control device arranged on each AIG branch pipe 20'vIf the actual flow rate is Q'vWhen the flow rate of the mixed gas is within the preset effective mixed gas flow threshold range, all the paths of the AIG branch pipes 20 and the ammonia injection grids 30 thereof are in a normal working state, and the compressed air purging valves 54 on the compressed air purging pipelines 53 on the AIG branch pipes 20 in the normal working state are always in a normally-off state; if the actual flow Q 'of the ammonia gas-air mixed gas in any AIG branch pipe'vAnd if the flow rate of the mixed gas exceeds the preset effective mixed gas flow rate threshold range, the AIG branch pipe or the ammonia spraying grid of the AIG branch pipe fails, and the unit DCS control system sends alarm information.
Wherein the actual flow rate Q 'of the ammonia-air mixture gas in each AIG branch pipe 20'vThe calculation is performed according to the following formula (1):
Figure BDA0003417018290000051
in the formula (1), the first and second groups,
Q'vactual ammonia-air mixture flow per AIG branch line (unit m)3/h)；
K is the coefficient;
d, measuring the opening diameter (unit mm) of a throttle orifice of the control device on line by the ammonia spraying flow;
ε -coefficient of dielectric expansion;
alpha is the flow coefficient;
Δ P-orifice differential pressure (in Pa);
rho-density of ammonia-air mixture gas (unit kg/m)3)。
The DCS control system of the unit presets the effective mixed gas flow threshold range in each AIG branch pipe to be Qvmin≤Q'v≤QvmaxWherein Q isvmaxFor maximum controlled flow, Q, of mixed gas in each AIG branchvminThe minimum control flow of the mixed gas in each AIG branch pipe is provided.
Maximum control flow Q of mixed gas in each AIG branch pipevmaxMinimum control flow QvminIs determined by firstly diluting the air flow Q according to a single reactorDilution windThe conversion volume flow Q of the ammonia injection amount of a single reactorNH3To calculate the flow rate of the ammonia-air mixture gas of each AIG branch pipe
Figure BDA0003417018290000052
Where n is the number of AIG branches, Qv、QDilution wind、QNH3All units of (are m)3H; then according to the obtained QvDetermining the maximum ammonia injection amount and the minimum ammonia injection amount of the SCR reactor according to the denitration design specification and the design operation condition, and determining the maximum control flow Q of the mixed gas in each AIG branch pipe according to the maximum ammonia injection amount and the minimum ammonia injection amount of the SCR reactorvmaxAnd a minimum control flow Qvmin。
When the DCS control system of the unit monitors the actual mixed gas flow Q 'in a certain AIG branch pipe'vLess than minimum control flow QvminAnd when the unit DCS control system judges that the nozzles of the ammonia spraying grids of the AIG branch pipe are blocked, the unit DCS control system sends out monitoring alarm and controls the compressed air purging pipeline on the AIG branch pipe to be opened so as to purge the AIG branch pipe.
When the unit DCS control system controls compressed air purging on the AIG branch pipe with the nozzle blockage fault, the compressed air purging valve 54 on the corresponding branch pipe is controlled to be opened while the pneumatic cut-off valve 61 on the AIG branch pipe is controlled to be closed, and the end of purging or the continuous purging is judged according to the compressed air purging pressure P', as shown in figure 2. Wherein, P' > P, the purging and clearing of the branch pipeline blockage is not completed; and P' < P, finishing the purging and clearing of the branch pipeline blockage. And P is the fixed value of the pressure of the compressed air pipeline determined when compressed air flows through the branch pipeline under the condition that the branch pipeline is not blocked.
And when the set DCS control system monitors the actual mixed gas flow Q 'in a certain AIG branch pipe'vGreater than the maximum control flow QvmaxThen the DCS control system of the unitJudging whether the AIG branch pipe has a wear fault, and sending out a monitoring alarm by a DCS control system of the unit at the moment; the operator needs to close the pneumatic shutoff valve of the branch pipeline in time and report for maintenance, and the standby unit is shut down or the pipeline is replaced in time in a window period.
In the actual SCR denitration operation, operators can periodically purge each ammonia spraying pipeline and each nozzle by compressed air through a monitoring picture to prevent the ammonia spraying branch pipeline or each nozzle from being blocked; the invention has the advantages of simple structure, real-time, rapid and reliable fault diagnosis, low construction cost, suitability for all SCR denitration AIG ammonia injection grid systems, simple system operation and maintenance, improvement of the automatic operation level of SCR denitration and the like.
The detailed description of the embodiments of the present invention is provided above, but the present invention is only the preferred embodiments of the present invention, and should not be considered as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the invention shall fall within the scope of the patent coverage of the present invention.

Claims (10)

  1. The utility model provides an online ash blockage prevention purge system of SCR denitration ammonia injection grid, it is including leading to the female pipe of air feed that has ammonia air mist, parallelly connected has a plurality of AIG branch pipes on the female pipe of air feed, every the AIG branch pipe all communicates to SCR reactor entry flue through the ammonia injection grid that connects separately in, its characterized in that: the compressed air blowing device comprises a compressed air tank, a compressed air conveying main pipe and a compressed air blowing pipeline, wherein the compressed air conveying main pipe is connected with the compressed air tank, one compressed air blowing pipeline capable of being connected or blocked in real time is arranged between each AIG branch pipe and the compressed air conveying main pipe, and each AIG branch pipe is also provided with a group of ammonia blowing flow online measurement control devices connected with a unit DCS control system through signals; the ammonia injection flow online measurement control device comprises a pneumatic shutoff valve and a flow monitoring assembly which are arranged on AIG branch pipes, wherein the flow monitoring assembly comprises a throttle orifice plate, an on-site differential pressure gauge and a flow transmitter; the on-site pressure difference meter and the flow transmitter of each group of the on-line measuring and controlling device are in signal connection with the unit DCS control system, and the unit DCS control system can calculate the actual flow of the ammonia-air mixed gas in each AIG branch pipe in real time according to the received on-site pressure difference meter signal and flow transmitter signal data of the flow monitoring assembly on each AIG branch pipe and judge whether the nozzle is blocked or the pipeline is abraded on the AIG branch pipe according to the actual flow.
  2. 2. The on-line ash blockage preventing and purging system for the SCR denitration ammonia injection grid according to claim 1, is characterized in that: and a compressed air purging valve is arranged on each compressed air purging pipeline.
  3. 3. The on-line ash blockage preventing and purging system for the SCR denitration ammonia injection grid according to claim 2, is characterized in that: and a compressed air local pressure meter and a pressure transmitter are arranged on the compressed air conveying main pipe and positioned on the first path and on the front side of the compressed air purging pipeline.
  4. 4. The fault diagnosis method of the SCR denitration ammonia injection grid online ash blockage prevention purging system based on the claim 3 is characterized in that: the ammonia gas and air mixed gas in the mixed gas main pipe in SCR denitration operation is sent into an inlet flue of an SCR reactor through each AIG branch pipe and an ammonia spraying grid thereof, and the actual flow Q 'of the ammonia gas and air mixed gas in each AIG is monitored in real time by the DCS of the unit through the online ammonia spraying flow measuring and controlling device arranged on each AIG branch pipe'vIf the actual flow rate is Q'vWhen the flow rate of the mixed gas is within the preset effective mixed gas flow threshold range, all the AIG branch pipes and the ammonia spraying grids thereof are in a normal working state, and the compressed air purging pipelines on the AIG branch pipes in the normal working state are always in a normally-off state; if ammonia gas and air mixed gas in any AIG branch pipeActual flow rate Q'vAnd if the flow rate of the mixed gas exceeds the preset effective mixed gas flow rate threshold range, the AIG branch pipe or the ammonia spraying grid of the AIG branch pipe fails, and the unit DCS control system sends alarm information.
  5. 5. The fault diagnosis method according to claim 4, characterized in that: actual flow Q 'of ammonia-air mixed gas in each AIG branch pipe'vThe calculation is performed according to the following formula (1):
    Figure FDA0003417018280000011
    in the formula (1), the first and second groups,
    Q'vactual ammonia-air mixture flow per AIG branch line (unit m)3/h)；
    K is the coefficient;
    d, measuring the opening diameter (unit mm) of a throttle orifice of the control device on line by the ammonia spraying flow;
    ε -coefficient of dielectric expansion;
    alpha is the flow coefficient;
    Δ P-orifice differential pressure (in Pa);
    rho-density of ammonia-air mixture gas (unit kg/m)3)。
  6. 6. The fault diagnosis method according to claim 4, characterized in that: the DCS control system of the unit presets the flow threshold range of the effective mixed gas in each AIG branch pipe to be Qvmin≤Q'v≤QvmaxWherein Q isvmaxFor maximum controlled flow, Q, of mixed gas in each AIG branchvminThe minimum control flow of the mixed gas in each AIG branch pipe is provided.
  7. 7. The fault diagnosis method according to claim 6, characterized in that: the maximum control flow Q of the mixed gas in each path of AIG branch pipevmaxMinimum control flow QvminIs determined by firstly diluting the air flow Q according to a single reactorDilution windSingle tableConversion volume flow Q of ammonia injection amount of reactorNH3To calculate the flow rate of the ammonia-air mixture gas of each AIG branch pipe
    Figure FDA0003417018280000021
    Where n is the number of AIG branches, Qv、QDilution wind、QNH3All units of (are m)3H; then according to the obtained QvDetermining the maximum ammonia injection amount and the minimum ammonia injection amount of the SCR reactor according to the denitration design specification and the design operation condition, and determining the maximum control flow Q of the mixed gas in each AIG branch pipe according to the maximum ammonia injection amount and the minimum ammonia injection amount of the SCR reactorvmaxAnd a minimum control flow Qvmin。
  8. 8. The fault diagnosis method according to claim 6, characterized in that: when the DCS control system of the unit monitors the actual mixed gas flow Q 'in a certain AIG branch pipe'vLess than minimum control flow QvminAnd when the unit DCS control system judges that the nozzles of the ammonia spraying grids of the AIG branch pipe are blocked, the unit DCS control system sends out monitoring alarm and controls the compressed air purging pipeline on the AIG branch pipe to be opened so as to purge the AIG branch pipe.
  9. 9. The fault diagnosis method according to claim 8, characterized in that: when the unit DCS control system controls compressed air purging on the AIG branch pipe with the nozzle blockage fault, the pneumatic shutoff valve on the AIG branch pipe is controlled to be turned off, meanwhile, the compressed air purging valve on the corresponding branch pipe is controlled to be opened, and the end of purging or continuous purging is judged according to the compressed air purging pressure P'; wherein, P' > P, the purging and clearing of the branch pipeline blockage is not completed; and P' < P, finishing the purging and clearing of the branch pipeline blockage. And P is the fixed value of the pressure of the compressed air pipeline determined when compressed air flows through the branch pipeline under the condition that the branch pipeline is not blocked.
  10. 10. The fault diagnosis method according to claim 6, characterized in that: DCS control system of current unitActual mixed gas flow Q 'in one AIG branch pipe is monitored systematically'vGreater than the maximum control flow QvmaxAnd when the machine set DCS control system judges that the AIG branch pipe has the abrasion fault, the machine set DCS control system sends out monitoring alarm.
CN202111550396.3A 2021-12-17 2021-12-17 SCR denitration ammonia-spraying grid online ash blocking prevention purging system and fault diagnosis method Pending CN114367195A (en)

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