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DLT468-2019

Chinese Standard: 'DLT468-2019'
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BASIC DATA
Standard ID DL/T 468-2019 (DL/T468-2019)
Description (Translated English) Guide on type selection and application for power boiler fans
Sector / Industry Electricity & Power Industry Standard (Recommended)
Word Count Estimation 34,398
Date of Issue 2019-06-04
Date of Implementation 2019-10-01
Older Standard (superseded by this standard) DL/T 468-2004
Regulation (derived from) Natural Resources Department Announcement No. 7 of 2019

DL/T 468-2019
Guide to selection and application of boiler fans for power plants
ICS 27.060.01
J 72
People's Republic of China Electric Power Industry Standard
Replace DL/T 468-2004
Guidelines for Selection and Use of Fans for Power Station Boilers
2019-06-04 released
2019-10-01 implementation
Issued by National Energy Administration
Table of contents
Foreword...II
1 Scope...1
2 Normative references...1
3 Terms and definitions...1
4 Design requirements for fans...4
5 Fan selection...5
6 Fan operation...8
7 Fan noise...9
8 Test and acceptance of fan...9
9 Fan system design...11
Appendix A (informative appendix) Necessary information for fan selection...25
Appendix B (Informative Appendix) Necessary information for evaluating fan design...28
Appendix C (Informative Appendix) Calculation of Humid Air Standard Density...34
Preface
This standard is drafted in accordance with GB/T 1.1-2009 "Guidelines for Standardization Part 1.Standard Structure and Writing Rules".
Please note that certain contents of this standard may involve patents. The issuing organization of this standard does not bear the responsibility for identifying these patents.
This standard replaces DL/T 468-2004 "Guidelines for Selection and Use of Fans for Power Station Boilers". This standard is compared with DL/T 468-2004, except
The main technical content changes are as follows.
-Revised Chapter 3 "Terms and Definitions", the definitions of blower and induced draft fan;
-Added Chapter 3 "Terms and Definitions", the definition of the stall safety factor of axial flow fans;
--- Added Chapter 3 "Terms and Definitions", definitions of basic air volume, basic pressure and selection conditions;
-The title of Chapter 4 "Design Requirements for Fans" is revised;
-Deleted Chapter 4 "Design Requirements for Fans", related content about fan manufacturing requirements;
-Revised the title of Chapter 5 "Van Type Selection";
--- Added Chapter 5 "Fan Selection", giving out the original data requirements for fan selection;
-Modified Chapter 5 "Fan Selection", the requirements on the selection of fan speed;
-Modified Chapter 5 "Selection of Fans", the requirements on the number of fans selected;
-Modified Chapter 5 "Fan Selection", the requirements on fan adjustment methods;
-Modified Chapter 5 "Fan Selection", the requirements on the stall safety factor of the axial flow fan;
-Deleted Chapter 6 "Installation of Fans" of the original standard;
--The serial number of Chapter 7 of the original standard has been revised to 6, and the serial numbers of subsequent chapters have been extended;
-Modified Chapter 6 "Fan Operation", the requirements for operating parameter control.
This standard was proposed by the China Electricity Council.
This standard is under the jurisdiction of the Power Plant Boiler Standardization Technical Committee (DL/T C08).
Drafting organization of this standard. Xi'an Thermal Power Research Institute Co., Ltd.
Drafters of this standard. Liu Jiayu, Dong Kangtian, Yan Hong, Zheng Jin.
The opinions or suggestions during the implementation of this standard are fed back to the Standardization Management Center of China Electricity Council (No. 2 Baiguang Road, Beijing)
One, 100761).
Guidelines for Selection and Use of Fans for Power Station Boilers
1 Scope
This standard specifies the basic requirements for the selection, use, and layout design of fan inlet and outlet ducts for power station boiler fans.
This standard applies to the blower, induced draft fan, primary fan, exhaust fan (pulverized coal fan), flue gas recirculation fan,
The booster fan of the flue gas desulfurization device and the sealed fan for the coal mill. Other small fans for boilers such as ignition fan, cooling fan, SCR
The dilution fan of the denitration system can be used as reference.
This standard does not apply to oxidation fans of desulfurization systems and high-pressure fluidized fans of circulating fluidized bed boilers.
2 Normative references
The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document.
For undated references, the latest version (including all amendments) applies to this document.
GB/T 1236 Industrial ventilators use standardized ducts for performance testing (IDT ISO 5801..1997)
GB/T 2888 Noise measurement method for fans and Roots blowers
GB/T 3235 Ventilator basic type, size parameter and performance curve
GB/T 3947 Acoustic terms
GB/T 10178 Field Performance Test of Industrial Ventilator (IDT ISO 5802.2001)
GB/T 17774 Industrial Ventilator Dimensions
GB/T 19075 Industrial Ventilator Vocabulary and Type Definition
GB 50660 Design Code for Large and Medium-sized Thermal Power Plants
DL/T 469 Field Performance Test of Power Station Boiler Fan
DL/T 5121 Technical specification for design of smoke, wind and pulverized coal pipelines in thermal power plants
DL/T 5145 Technical Regulations for Design and Calculation of Pulverizing System in Thermal Power Plants
DL 5190.2 Technical Code for Power Construction Construction Part 2.Boiler Unit
JB/T 4358 Centrifugal fan for power station boiler
JB/T 4362 Axial fan for power station
JB/T 6891 Technical conditions of muffler for fan
JB/T 8689 Ventilator vibration detection and its limits
JB/T 8690 Noise limit of industrial fans
Technical conditions of JB/T 8822 high temperature centrifugal fan
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
A fan that supplies the air required for the fuel combustion of the boiler. Arranged before the boiler air preheater. Send air sucked from the atmosphere into the air
The preheater, after being heated to the design temperature, is used as the secondary air of the boiler for the direct-blowing pulverizing system and is directly sent into the boiler furnace through the burner;
For the silo-type pulverizing system, part of it is used as the secondary air of the boiler, which is directly sent to the boiler furnace through the burner, and the other part enters the pulverized coal
The preparation system is used as a desiccant, and then, or used as primary air to transport pulverized coal into the furnace through the burner (exhausted gas powder delivery system), or as a third
The air is sent into the furnace through the burner (hot air powder feeding system). Large-scale boiler adopts medium-speed coal mill or double-inlet and double-outlet steel ball coal mill with positive pressure direct blowing system
The powder system is equipped with a high-pressure cooling primary fan. If the primary fan draws air from the outlet of the blower, the blower supplies the total air required by the boiler
There are also those designed to inhale air from the atmosphere. At this time, the blower only supplies the secondary air of the boiler, also known as the secondary fan.
3.2
Induced draft fan (IDF)
Installed after the boiler dust collector, the boiler combustion products (flue gas) are sucked out from the tail of the boiler and sent into the denitrification system and dust removal system
The booster fan of the desulfurization system is a fan that is discharged into the atmosphere from the chimney through the desulfurization system after the pressure is increased, also called a suction fan. If there is no booster fan,
The resistance of the entire flue gas system from the boiler furnace to the chimney outlet is overcome by the induced draft fan (commonly known as the two-in-one induced draft fan).
3.3
Primary fan (PF)
A fan that supplies the primary air required for the fuel combustion of the boiler. According to its installation position in the system, there are cold primary fans and hot primary fans
Minute.
3.4
Cold primary fan
Installed before the boiler air preheater, the air sucked from the atmosphere or the cold air duct at the outlet of the blower is heated by the air preheater and then sent
It is sent to the primary fan of the pulverizing system.
3.5
Hot primary fan
Installed after the boiler air preheater, the hot air heated by the boiler air preheater is sent to the direct blowing pulverizing system or only
The primary fan that sends pulverized coal into the boiler.
3.6
Powder exhaust fan exhauster
The fan used in the pulverized coal preparation system to transport desiccant and pulverized coal. Mainly used in the intermediate storage bin type powder system, installed in the fine powder
After the device. Also known as pulverized coal fan.
3.7
Flue-gas recirculating fan
Take a part of the flue gas from the front of the air preheater after the economizer, the lower part of the furnace, after the electric dust removal, the outlet of the induced draft fan, etc., and transport it into the pot
Furnace cold ash hopper or upper part of the furnace, used to adjust the boiler steam temperature; or sent to the inlet of the coal mill to adjust the temperature or oxygen content of the fan.
3.8
Flue gas desulfurization booster fan (FGDP fan or BUF)
DL/T 468-2018
A fan installed behind the induced draft fan to overcome the resistance of the flue gas desulfurization system.
3.9
Seal air fan
Fans that supply air for sealing in medium-speed coal mills, double-inlet and double-outlet steel ball coal mills and coal feeders. The sealed fan can be directly from the atmosphere
Inhale air, or from the outlet duct of the blower or primary fan.
3.10
A1 inlet plane and inlet area of fan
Take the interface at the upstream end of the air conveying device as the fan inlet plane. Usually, take the inlet of the casing (the fan with the air intake box takes the air intake box)
The total flow area of the (flange) plane is used as the fan inlet area.
3.11
A2 outlet plane and outlet area of fan
The interface at the beginning of the downstream section of the air conveying device is taken as the fan outlet plane. Generally, the total area of the plane of the outlet (flange) of the casing is taken as the wind
Machine exit area.
3.12
Stall safety factor of axial flow fans
This standard indicates the amount of stall margin of axial flow fan, expressed by k (see 5.6.4).
3.13
Fan system
In order to convey air or gas from one or more places to another or more places, the fans and the equipment on the conveying path and a series of air ducts and pipes
A system composed of roads, bends and branch pipes.
3.14
System characteristic curves
The system characteristic curve is an illustration of the resistance of a certain system to the characteristic of volume flow.
3.15
System effect
The influence of system layout on fan performance is called system effect. The performance of the ventilator is affected by its inlet and outlet connecting pipes. If even
Improper connection, uneven airflow at the inlet, and vortex at the inlet of the ventilator will change the aerodynamic characteristics of the ventilator and reduce the ventilator
Performance.
3.16
System effect loss
The decrease in fan pressure caused by system effects.
DL/T 468-2018
3.17
Base flow
The fan flow required for the maximum continuous evaporation of the boiler calculated according to the design coal type.
3.18
Base pressure
The total resistance of the fan system when the boiler is operating with the maximum continuous evaporation calculated by the design coal type.
3.19
Selection condition (TB condition) test block
The maximum continuous operating conditions that the fan should reach when the selection requires.
3.20
Specific A sound level (LSA)
The A sound level is the A sound level per unit flow rate and unit fan pressure.
4 Design requirements of the fan
4.1 General requirements
4.1.1 The design of the fan should meet the requirements of GB/T 3235 and GB/T 17774.
4.1.2 The design and manufacture of centrifugal fans should meet the requirements of JB/T 4358.
4.1.3 The design and manufacture of axial fans shall comply with the requirements of JB/T 4362.
4.1.4 The natural vibration frequency of the fan impeller (or blade) should avoid the speed frequency of the impeller and its multiplication frequency below 10 times and other dangerous frequencies, such as
The passing frequency of blades is the speed (fans that adopt speed adjustment include all speeds within the speed adjustment range) and the number of blades (including rotor blades).
And the product of the front and rear adjustment of the impeller or the guide blade), the high-amplitude airflow pulsation frequency, etc.
4.1.5 For fans with variable speed adjustment, calculation of torsional vibration of the shaft system shall be carried out to prevent the occurrence of shaft system torsional vibration.
4.1.6 The fan should be equipped with necessary automatic alarm and protection devices (such as bearing temperature, oil cut, vibration and stall surge of axial fan, etc.).
4.1.7 Fans that suck from the atmosphere (such as blowers and primary fans) should be equipped with imported mufflers. The design and manufacture of the mufflers should comply with JB/T
The provisions of 6891.
4.2 Design requirements
4.2.1 The designed inlet air temperature of the hot primary fan is 250°C, and the maximum allowable inlet air temperature does not exceed 400°C. The air is densely dusty.
The degree does not exceed 100mg/m3.Its design should comply with the regulations of JB/T 8822.
4.2.2 The flue gas system upstream of the induced draft fan is equipped with a low-temperature economizer system, and the inlet temperature of the induced draft fan is about 90℃, which is corrosive.
Reliable anti-corrosion measures should be taken for the flow part of the fan.
4.2.3 The design of the exhaust fan (pulverized coal fan) requires that the conveyed medium is air containing pulverized coal. The pulverized coal content of the steel ball mill
The exhaust gas of the bin-type pulverizing system is not more than 80g/m3, and for the negative pressure direct-blowing pulverizing system, it is 300g/m3~800g/m3.Its designed inlet gas temperature
The temperature is 700℃, and the maximum allowable inlet gas temperature is 150℃. The casing and impeller should be based on the wear characteristics of coal (see DL/T for the wear index
5145) Take anti-wear measures, and the service life of its impeller is not less than 8000h.
4.2.4 The design of the flue gas recirculation fan requires that the transported medium is hot flue gas with an ash content of not more than 20g/m3 and a temperature of not more than 400℃. its
The volute and the impeller should take appropriate anti-wear measures; the bearing should be equipped with special heat insulation and cooling devices, and its service life should not be less than 8000h.
The flue gas recirculation machine without speed control device should be equipped with a cranking device.
4.2.5 The design of the sealed fan shall adopt noise reduction measures. For sealed fans that directly suck in air from the atmosphere, they should be equipped with inlet filters and inlets and outlets.
silencer.
5 Selection of fan
5.1 Raw data that should be provided for selecting the fan
The original data that should be provided for selecting a wind turbine include at least the following.
a) Local atmospheric conditions.
1) Atmospheric pressure;
2) Dry and wet air temperature;
3) Relative humidity of air.
b) Boiler thermal calculation and aerodynamic calculation results;
c) Fan parameters of the boiler under various typical working conditions.
1) Flow rate (air volume, flue gas volume);
2) The total resistance of the fan inlet side system (that is, the total pressure of the fan inlet) and the corresponding dynamic pressure of the fan inlet air duct section;
3) The total resistance of the system on the outlet side of the fan (that is, the total pressure at the outlet of the fan);
4) The total resistance of the wind (smoke) system (ie the pressure of the fan, formerly called the total pressure of the fan);
5) Medium temperature;
6) The standard density of the medium (the air medium is the standard density of the local moist air; the flue gas medium is the standard density of the wet smoke at the fan inlet
degree).
d) The annual operating hours of the unit under different loads.
5.2 Determination of fan selection parameters
5.2.1 The basic air volume is determined according to the following requirements.
a) For the fans of newly-built boilers, the basic air volume shall be determined according to the relevant regulations of GB 50660.
b) For the retrofitted fan that has been put into operation, the basic air volume needs to be determined by field tests. No less than three test conditions (in the high, medium, and
Under three low loads), and convert the test results to the flow rate under the maximum continuous evaporation capacity (BMCR) of the boiler.
5.2.2 The basic wind pressure is determined according to the following requirements.
a) For the fan of a newly built boiler, the basic air pressure is calculated according to the relevant regulations of GB 50660, and the calculated fan system resistance
Liyi refers to the actual operating value of the same type of unit to determine whether adjustment is needed.
b) For the retrofitted fan that has been put into operation, the basic wind pressure is determined by field test (the wind pressure test should be carried out simultaneously with the flow test, and
Collect the resistance of the main equipment and related pipelines in the system through the DCS system). Measure and/or pass SIS when necessary
The system collects and checks the inlet and outlet pressure values of the fan when the unit is fully loaded in the past year. The corresponding system (including
The resistance changes caused by the modification of other equipment in the system. And convert it to the maximum continuous evaporation capacity (BMCR) of the boiler
The total resistance of the system is determined as the basic wind pressure for fan selection.
5.2.3 Air volume and wind pressure margin are selected according to the following requirements.
a) For the fan of a newly-built boiler, the margin of flow and pressure should be selected within the range of relevant regulations in GB 50660.
b) Transformation of fans that have been put into operation, fan flow rate and pressure margin, should consider the climatic conditions during the test period and the local summer and winter seasons before the change.
Determined on the basis of factors such as differences, boiler equipment and flue gas system operating conditions, unit load factor and coal quality change range;
It can also be selected within the specified range of GB 50660.
5.3 Selection of fan speed, number and type
5.3.1 Selection of fan speed. Generally, a 4-pole motor (1490r/min) should be used for the primary fan; a 4-pole or 6-pole motor should be used for the blower.
Pole motor (1490r/min or 990r/min); the speed of the induced draft fan and desulfurization booster fan should be a motor with 6 poles or less (that is, the highest
990r/min), for the stator-blade-adjusted axial-flow induced draft fan with the combined induction and booster fans with variable speed regulation, the higher than
The speed is 990 r/min, but it needs to meet the requirements of structural strength and rigidity reliability.
5.3.2 The selection of the number of fans is in accordance with the following requirements.
a) For units of 50MW and above, the number of boiler fans should comply with the relevant regulations of GB 50660 (the primary fan for delivery, induction and cooling should be
Set up 2 sets; the number of booster fans should be the same as the number of desulfurization devices; the number of pulverizers should be the same as the number of coal mills; the pulverizing system
Two sealed fans are installed for each furnace, one for transportation and one for preparation).
b) One blower and two induced draft fans should be installed for the boiler supporting the 25MW-class unit, but one fuel gas negative pressure boiler should be installed
A blower and an induced draft fan.
c) One blower and one induced draft fan should be installed for boilers supporting units of 12MW and below.
d) For 50MW~600MW-class generating units, if it is feasible through technical and economic demonstration and reliability demonstration, only one transmitter per boiler can be used.
Fans, one induced draft fan and one primary fan.
e) Depending on the layout conditions and the design load rate of the unit, 3 to 4 induced draft fans can also be installed when it is technically and economically feasible.
5.3.2 Selection of the fan type According to the TB working condition parameters and the selected fan speed, the specific speed of the required fan is calculated, and then the best specific speed is selected.
Close fan type. For given parameters, when several different types of fans can be selected, it should be based on the annual load curve of the boiler unit,
Fan power consumption, regulation efficiency, equipment cost, maintenance cost and other factors are selected by comprehensive technical and economic comparison. Ratio of different types of fans
Refer to Table 1 for the reference range of speed.
5.4 Selection of fan model
5.4.1 The principles to be followed to determine the fan model are as follows.
a) After the fan model is determined, the fan model can be determined according to similar design methods, and the resistance line of the system should completely fall on the selected fan
Within the stable region of the energy curve, and the stall margin is sufficient, see 5.6.4.
b) For centrifugal fans, avoid areas with high air flow pulsation.
c) When different types or models of fans can be selected, after satisfying the requirements of safe operation, it should be based on unit load, utilization hours, design
Technical and economic indicators such as reserve costs and annual maintenance costs determine the fan model.
5.4.2 The model of centrifugal fan should be selected so that the selection operating point (ie TB point) is as close as possible to the flow-pressure at the maximum opening of the regulating device.
The force curve is located on the right side of the maximum efficiency of the fan, and its efficiency value should not be lower than 90% of the maximum efficiency of the fan.
5.4.3 The model of axial flow fan should be selected under the premise that the fan selection working condition point (TB point) can operate safely and reliably, and the power generation should be made.
When the unit is operating under economic load (generally the rated output of the generator set), the fan runs in the highest efficiency zone.
5.4.4 The selection of axial flow fan should ensure sufficient stall margin. The definition and requirements of stall margin (stall safety factor) are as follows.
a) The stall margin can be expressed by the stall safety factor k, which is determined by each design operating point and the corresponding opening (moving blades are adjusted to the blade angle,
The stator blade is adjusted to adjust the flow and pressure of the stall operating point (or the maximum pressure point) of the angle of the guide vane, and calculated by the following formula
Out.
b) In the selection and design, the k value of each design operating point should be greater than 1.35, that is, k>1.35.
5.5 Selection of fan adjustment mode
5.5.1 For the moving blade adjustment axial flow fan, when the unit design load factor is less than 70%, and the design speed is below 1000r/min, the dynamic
Axial-flow fan with blade adjustment should use two-speed motor to adjust the number of poles or use a variable speed device (frequency converter, steam turbine drive or other variable speed device).
Set) adjustment, switch or adjust to low speed operation when the unit is running at low load. Special attention. the selection of the axial flow fan
When adjusting the speed, the manufacturer’s guarantee for the safety and reliability of the equipment's variable speed operation should be obtained.
5.5.2 For the stationary blade adjustment axial flow fan, when the unit design load factor is less than 80%, the stationary blade adjustment axial flow fan should be selected.
Speed device (frequency converter, steam turbine drive or other variable speed device) adjustment.
5.5.3 For centrifugal fans, inlet guides are generally selected for adjustment; in order to obtain better economy, a two-speed motor should be used for pole-changing adjustment.
Section or variable speed device (frequency converter, steam turbine drive or other variable speed device) adjustment.
5.5.4 For the powder exhaust fan (generally centrifugal), it is usually appropriate to choose the inlet throttle adjustment; the inlet adjustment door can also be used for adjustment, but it should be
The entrance door adopts corresponding sealing and anti-wear measures.
5.5.5 For fans with variable speed regulation, which variable speed regulation device to choose and its adjustment range should be determined through detailed technical and economic comparisons.
set.
5.6 The basic data requirements that the manufacturer should provide are as follows.
a) See Appendix A for necessary information about fan selection.
b) When evaluating the fans selected by each manufacturer, the minimum information usually required by the supplier is shown in Appendix B.
6 Fan operation
6.1 Operating area of the fan
6.1.1 In order to avoid the damage caused by high airflow pulsation to the fan, the centrifugal fan should not be operated in an unstable area that may cause surge.
It should not operate in the high pulsation area (if any) of the air flow, and should also avoid long-term operation of the inlet regulating door opening below 30%.
6.1.2 Axial fans should avoid all possible operating conditions from running in the stall area (unstable operating condition area).
6.2 Parallel operation of fans
6.2.1 When two fans are running in parallel, the operating point of the system is integrated by the respective operating points of each fan. If one fan stops running, another
The operating point of a fan will be matched according to the needs of the system resistance characteristics.
6.2.2 For centrifugal forward bending fans, when a fan is shut down, it is necessary to monitor the current of the fan to prevent the motor from overloading.
6.2.3 For axial fans, the maximum output of a single fan depends on the maximum operating angle of the moving blade (or stationary blade) and the motor capacity. when
When starting a deactivated fan, the isolation door should be closed and the blade angle (adjusting the moving blade to the angle of the moving blade, and adjusting the static blade to adjust the angle of the guide blade)
Should be adjusted to the minimum, when the fan reaches full speed, the isolation door opens. In any case, when the first fan is running, the pressure is higher than the second
When the pressure at the lowest point of the fan stall boundary line, the second fan should not be started for parallel connection. If parallel connection is required, the output of the first fan should be reduced
After reducing the operating point to the second stall limit pressure, start the second fan for parallel connection.
6.2.4 When the disabled fan starts again, the isolation door and the entrance regulating door of the fan should be closed to reduce the starting resistance torque and starting time.
If the fan is reversed before starting due to the leakage of the above-mentioned damper, you should be especially careful when starting (large centrifugal fans, especially induced draft fans)
Should be equipped with brake or turning device) to prevent damage to the motor due to too long starting time. Usually, when the fan without speed control and soft start equipment starts
The time should be limited to 25 seconds.
6.3 Fan operation, maintenance and inspection
6.3.1 The operating parameters of the fan such as air volume, wind pressure, current, bearing vibration, bearing temperature, and medium temperature at the inlet and (or) outlet of the fan
There should be an instrument display in the control room. For axial flow fans, it is advisable to display on the online monitoring screen that the fan operating conditions are located in the performance curve.
The position on the line, so that the operator can understand the actual operation of the fan, and avoid the fan from operating under undesired conditions. For large fans
Bearing vibration and temperature should also be equipped with alarm signals. All monitoring instruments should be calibrated regularly.
6.3.2 Regular maintenance and inspection of the fan, and timely troubleshooting of faults and abnormalities during operation. The main inspection items are. bearings, wear and
Corrosion degree, dust accumulation, welding seam and riveting quality, moving blade bolt connection, oil system, and adjusting mechanism of axial flow fan with adjusting blade,
Including the range of stroke, flexibility, the consistency of the action of each adjustment blade, and the consistency of the actual opening and the indicating instrument, etc.
6.3.3 Before the wind turbine is officially put into operation, each power plant should follow the information provided by the manufacturer and the specific conditions of the pipe network system, as well as the one after installation.
Based on the results of the series of adjustment tests, specific and feasible operating procedures for fan operation have been compiled as the basis for operation, inspection and maintenance by operators.
7 Fan noise
7.1 Limits and measurement methods of fan noise
7.1.1 The noise of the fan should meet the requirements of JB/T 8690.
7.1.2 The ratio A of the ventilator noise at the point of the best efficiency operating condition The limit of the sound level LsA should meet the requirements of Table 2.
7.1.3 The test method of fan noise is in accordance with GB/T 2888.
7.2 Methods to reduce noise
7.2.1 For fans that directly draw air from the atmosphere, a muffler can be installed in front of the fan inlet. The muffler should comply with the regulations of JB/T 6891 and be installed in
Lay sound-absorbing materials or/and use sound-proof enclosures or sound-proof rooms for sound insulation treatment on the outside of the casing.
7.2.2 For fans that do not directly draw air from the atmosphere, sound absorbing materials can be laid on the outer surface of the casing or/and a sound insulation cover or sound insulation room can be used for sound insulation
deal with.
7.2.3 Other noise reduction methods, such as applying damping materials, installing vibration absorbers, etc. to isolate vibration.
8 Test and acceptance of fan
8.1 Standards for performance test
8.1.1 The aerodynamic performance test of the fan shall be carried out in accordance with GB/T 1236.
8.1.2 The field performance test of the fan shall be carried out in accordance with GB/T 10178 or DL/T 469.
8.2 Performance test and related tests
8.2.1 After the fan is installed and tested normally, the fan performance test and actual system resistance test should be carried out. To determine the fan in the actual system
The performance and the actual position of each operating condition point in the performance curve to determine whether the fan selection is appropriate and whether there will be dangerous operating conditions during operation.
And how to avoid these possible dangerous conditions.
8.2.2 For fans equipped with stall protection devices, the accuracy of their actions should be tested and corrected before being officially put into operation. After the wind turbine is put into operation
It should also be tested and corrected regularly to ensure its accuracy.
8.2.3 Before the formal operation, the parallel operation of the wind turbines should be tested in parallel (including various parallel conditions that may be encountered in the formal operation).
In order to determine the correct parallel operation, to avoid the occurrence of "wind grabbing".
8.2.4 After each fan is installed, a mechanical operation test shall be carried out. During the mechanical operation test, the vibration and temperature of each bearing should be measured,
The continuous operation time after the bearing temperature rise is stable shall not be less than 4h. The temperature rise of rolling bearings should not exceed 40℃, and the normal operating temperature should not exceed
70℃, the maximum temperature should not exceed 90℃. The operating temperature of the sliding bearing should not be higher than 75°C, and there should be no oil leakage. See 8.4.1 for the limit of vibration.
8.3 Tolerance of fan performance parameters
8.3.1 Under the specified fan flow rate, the corresponding fan pressure deviation is ±5%; under the specified fan pressure, the corresponding fan flow rate
The deviation is ±5%.
8.3.2 At a given speed, the allowable difference between the actual efficiency at the operating point and the given efficiency is. 3% when it is close to the highest efficiency point.
The high efficiency 90% range is 5%, and the other ranges are not assessed.
8.4 Measurement of fan vibration speed
8.4.1 Root mean square limit of vibration velocity
The root mean square value of the fan vibration speed (also called the effective value of the vibration speed) νrms (see JB/T 8689 for the definition), as specified in 8.4.2
The value measured on each measuring direction and measuring point shall not exceed the following regulations.
--Rigid support. νrms≤4.0 mm/s
--Flexible support. νrms≤6.3 mm/s
Note 1.Rigid support means that after the fan is installed, the basic natural frequency of the "fan-support system" is higher than the main frequency of the fan. Such as the general fan directly
The rigid foundation is tightly connected.
Note 2.Flexible support means that after the fan is installed, the basic natural frequency of the "fan-support system" is lower than the main frequency of the fan. If under special conditions,
The fan is connected to the foundation through a vibration isolator.
Note 3.The limit specified in this standard is one level higher than that specified in JB/T 8689, JB/T 4358, and JB/T 4362.After signing a supply agreement with the manufacturer
At the time, this request should be specifically made.
8.4.2 Bearing vibration measurement location
8.4.2.1 For a fan with two bearing bodies with dual supports, measure the vibration value of each bearing in the three directions shown in Figure 1.
8.4.2.2 When two bearings are installed in the same bearing box, measure the vibration value at the bearing part of the bearing box according to the requirements shown in Figure 2.
8.4.2.3 When the bearing box to be tested is inside the ventilator housing, a vibration sensor shall be installed in advance according to the requirements of 8.4.2.1 or 8.4.2.2.
After leading out the fan to connect with the indicator to measure its vibration value. The deviation between the installation direction of the sensor and the measurement direction shall not be greater than ±5°.
8.4.2.4 When the tested bearing box is inside the fan housing and the vibration sensor cannot be preset, the fan housing at the supporting bearing can be
The vibration value of the vertical and horizontal directions should be measured at the location, see Figure 3.
8.4.3 Limits of the peak value of fan vibration speed (or displacement peak-peak value)
If the existing vibration measuring instrument does not have the effective value detection function, the vibration speed (peak value) or vibration displacement (peak value) can be measured with the approval of the manufacturer.
-Peak), their limits are shown in Table 3.
9 System design of fan
9.1 Basic requirements for fan system design
9.1.1 In addition to the following provisions of this standard, the design of the inlet and outlet ducts of the fan shall comply with the relevant regulations in DL/T 5121.
9.1.2 The inlet and outlet of the fan shall be equipped with compensators to absorb the thermal expansion of the piping system and isolate vibration.
9.1.3 The outlet and inlet of the fan need to be equipped with an isolation damper for maintenance that can be operated remotely (except for the inlet of the fan that is directly sucked from the atmosphere.
Outside); the air leakage rate of the isolation damper should be less than 2%; the opening and closing time of the damper should not be greater than 45s or as specified by the manufacturer.
9.1.4 When two or more fans are required to operate in parallel, the design of the fan system should be such that any fan can be easily integrated into the system
in. In order to facilitate the parallel connection of fans and reduce the impact on the boiler load when a fan is disabled due to a failure, a connecting air should be set up between the parallel fans.
(Smoke) Road.
9.1.5 The cross-sectional area of the fan inlet pipe should neither be greater than 112.5% of the fan inlet area, nor less than 92.5% of the fan inlet area.
The included angle of the convergent connecting pipe is not greater than 15°, and the included angle of the diffuse connecting pipe is not greater than 7°. See Figure A.1.
9.1.6 The cross-sectional area of the outlet duct of the fan should neither be greater than 105% of the outlet area of the fan, nor less than 95% of the outlet area of the fan. with
It is required that the inclination of the convergent connecting pipe does not exceed 15°, and the inclination of the diffusion connecting pipe does not exceed 7°. See Figure A.1.
9.1.7 The length of the straight pipe section of the fan inlet including the transition section should not be less than 3 times the equivalent diameter, otherwise the influence of the system effect should be considered.
9.1.8 The length of the straight pipe section at the outlet of the fan, including the transition section, should not be less than 2.5 to 6 times the equivalent pipe diameter, otherwise the influence of the system effect should be considered.
ring.
9.2 System effect loss
9.2.1 When the fan is installed in the system, its inlet and/or outlet conditions may deviate from the design state, and the performance of the fan will be reduced.
This is called a system effect. The resulting system loss is called system effect loss (SEF).
9.2.2 Curve A in Figure 4 is the system resistance curve when the system effect is not considered, and curve B is the actual system due to the influence of the system effect.
System resistance curve, the pressure difference under the same flow rate is the system effect loss (the pressure difference between point 3 and point 4, the pressure between point 1 and point 2
difference). Therefore, when selecting the fan, the system effect loss should be added to the total resistance of the system, otherwise the fan will not reach the design performance (Figure 4
Point 2).
9.3 System effect curve
9.3.1 Figure 5 shows 19 system effect curves, among which 19 different curves (F, G, H,, X) correspond to 19 different fan inlets,
Please refer to 9.4 and 9.5 for the layout of outlet piping.
9.3.2 According to the average airflow velocity at the inlet or outlet of the fan and the system effect curve corresponding to the pipeline arrangement, the corresponding arrangement can be found
The system effect loss (SEF, Pa) corresponding to the method. The speed of the inlet and outlet of the fan is calculated according to the cross-sectional area of the equipment inlet boundary provided by the manufacturer
Calculated. For the axial flow fan, the inlet and outlet speeds can also be approximated by calculating the outer diameter (flow area) of the impeller.
9.3.3 The system effect loss can also be calculated according to the calculation formula of the dynamic pressure loss coefficient C and the system effect loss corresponding to the pipeline layout in Table 4.
The formula is calculated, where V is the corresponding gas flow velocity and ρ is the gas density.
9.3.4 In Sections 9.4 and 9.5, typical inlet and outlet piping arrangements and corresponding system effect curves are given. If a system
Including multiple arrangements that produce system effects, then the system effect loss of each arrangement should be determined separately and then added together to get
The total system effect loss.
9.3.5 The system effect curve in Figure 5 is given at a standard air density of 1.2kg/m3.The system effect loss detected or calculated is called the standard system effect.
System effect loss, the actual system effect loss can be corrected as follows.
2.1
Actual density standard system effect loss Actual system effect loss×=
9.4 System effect loss of fan outlet
9.4.1 The typical outlet pipe velocity distribution of the outlet pipe is shown in Figure 6, which shows the velocity at different distances from the outlet of centrifugal and axial fans.
Degree distribution changes. Among them, 100% of the "effective pipe length" is at least 2.5 times the pipe equivalent diameter. When the air velocity is greater than 13m/s
When increasing by 5m/s, the pipe length needs to increase by 1 pipe diameter. For example, when the air velocity is 25.4m/s, the pipe length is 5 times
Equivalent diameter of the pipe; if it is a rectangular pipe with side lengths a and b, the equivalent diameter is (4ab/π)0.5.
9.4.2 The system effect of the outlet duct of the axial flow fan is in accordance with the following requirements.
a) It is generally required that the outlet of the axial flow fan should be installed with a straight pipe with a length of 2 to 3 times the equivalent diameter of the pipe;
b) For tubular axial fans, there is generally no outlet pipe, and the system effect loss at this time is close to 0;
c) For the guide vane axial flow fan, the straight pipe length at the outlet should not be less than 50% of the effective pipe length;
d) When the length of the outlet pipe is less than the optimal value, the system effect curve of the axial flow fan is shown in Table 5;
e) According to the system effect curve type corresponding to the different piping arrangements selected in Table 5, the average outlet speed of the fan is calculated according to
(The abscissa in Figure 5), and the corresponding system effect loss can be obtained from Figure 5.
9.4.3 The system effect of the outlet duct of the centrifugal fan is in accordance with the following requirements.
a) The ventilation area of the centrifugal fan is the outlet area of the fan minus the projected area of the volute tongue, as shown in Figure 6;
b) When the length of the outlet pipe is less than the optimal value, the system effect curve of the centrifugal fan is shown in Table 6;
c) The system effect loss is determined by Figure 5.
9.4.4 Outlet elbow
9.4.4.1 A long straight pipe section should be arranged as far as possible between the fan outlet and the elbow. If the elbow must be arranged near the outlet of the fan,
The ratio of the radius of curvature of the pipe to the diameter of the pipe shall not be less than 1.5.
9.4.4.2 Figure 7 shows the layout of the outlet elbow of the axial flow fan. The system effect of the outlet elbow is in accordance with the following requirements.
Figure 7 Axial fan outlet elbow
a) For tubular axial flow fans, the outlet is equipped with a 2-piece or 4-piece miter elbow, and the system effect loss can be ignored (see Table 7).
b) For the guide vane axial flow fan, the outlet is equipped with a elbow, and the corresponding system effect curve is shown in Table 7.
9.4.4.2 The system effect of the centrifugal fan outlet elbow is in accordance with the following requirements.
a) When the elbow must be arranged near the outlet of the centrifugal fan, the ratio of the radius of curvature of the elbow to the pipe diameter should not be less than 1.5, and
The arrangement of elbows should be as uniform as possible.
b) Figure 8 is a schematic diagram of the position and direction of the outlet elbow of a single-inlet centrifugal fan.
c) Table 8 shows the system effect curve used to estimate the influence of the outlet elbow of the single-inlet centrifugal fan.
d) For the system effect loss of the dual-inlet fan, first determine the system effect loss (△p) according to the system effect curve of the single-inlet fan,
The calculation of the system effect loss of the dual-import fan is based on the following relationship.
9.5 System effect loss of fan inlet
9.5.1 Inlet elbow of axial fan
9.5.2 Bend at the inlet of centrifugal fan
9.5.2.1 Uneven airflow into the inlet (Figure 10A) is a common cause of insufficient fan performance. Figure 12 shows the 900 miter circular elbow
Figure 13 shows the system effect curve of various square elbows. According to these curves and the air velocity, it can be found from Figure 5.
Their systemic effects are lost. This pressure loss should be added to the friction and dynamic pressure loss of the elbow.
9.5.2.2 If there are guide vanes and/or straight pipes (3-8 diameters long, depending on the speed) between the fan inlet and the elbow, this
The loss of the system effect is not large.
9.5.2.3 Due to space constraints, the inlet elbow may be installed directly at the inlet of the fan, as shown in Figure 10B, which will cause up to
45% of the fan capacity is lost, so similar inlet pipe section arrangements should not be used. In this case, a centrifugal fan with an air intake box (also
It is called a radial air intake centrifugal fan. At this time, the inlet of the fan is the inlet of the air inlet box), similar to that shown in Figure 11.
9.5.3 The air inlet box of the centrifugal and axial fan configuration can replace the inlet elbow. The fan performance provided by the manufacturer should include the influence of the air intake box,
And the loss of the air intake box should be included in the rated output of the fan. In the absence of data from the wind turbine manufacturer, a well-designed air intake box is close to
The similar system effect curve should be selected according to S or T in Figure 5.
9.5.4 When a good fan inlet condition cannot be achieved due to limited space, guide vanes should be arranged in the inlet elbow (see Figure 14). Imported elbow
There are many types of guide vanes, such as single arc blades, multi-blade airfoil blades and so on. When calculating the total resistance of the system, the loss of the guide vane should be considered in
Inside.
Appendix A
(Informative appendix)
Necessary information for fan selection
A.1 General information is as follows.
a) The number of boilers.
b) The number of fans for each boiler.
c) Burning fuel characteristics.
d) Site elevation.
e) Purpose.
f) The location of the fan (indoor or outdoor).
g) Wind type.
h) The layout of the fan.
i) Fan adjustment method (adjustable inlet guide vane, inlet box inlet adjustment door, moving blade adjustment, variable speed adjustment).
j) Accessories (diffuser, muffler, driving device, etc.) provided by the fan manufacturer.
k) The prime mover.
l) The dust content and particle size of the fan inlet.
m) Boiler load type-base load/peak load.
n) The load rate of the boiler.
o) Earthquake/seismic area.
A.2 The performance requirements are as follows.
a) Output (designed maximum output, maximum continuous output, low load).
b) Gas density (kg/m3).
c) Atmospheric pressure (at work site).
d) Gas composition.
e) Specific heat ratio (isentropic index).
f) Inlet volume flow (m3/s).
g) The static pressure (Pa) at the connection between the inlet pipe and the fan (or connector), see Figure A1.
h) Inlet pipe area (m2), see Figure A1.
i) The static pressure (Pa) at the junction of the outlet pipe and the fan (or connector), see Figure A1.
j) The area of outlet pipe (m2), see Figure A1.
k) Estimate the length of the inlet and outlet pipe connections, see Figure A1.
l) Inlet temperature (at all operating points).
m) The preferred fan speed (r/min).
n) Provision of diffuser (with/without).
A.3 Structure and special requirements
A.3.1 The requirements for rotating components are as follows.
a) Type of impeller (axial flow type, centrifugal type).
b) The type of blade (airfoil, forward curved, backward curved, backward flat, radial).
c) Anti-wear and anti-corrosion measures.
d) The minimum first-order critical speed of the impeller and shaft.
e) The minimum design resonance speed.
f) Peak temperature for design and operation.
g) The expected value of the design temperature change.
h) Extreme minimum temperature.
Figure A.1 Definition of the positions of the fan
A.3.2 The bearing requirements are as follows.
a) Preferred bearing type (rolling bearing, sliding bearing)
b) Special thrust requirements
c) Preferred bearing cooling
1) Natural cooling
2) Air cooling
3) Water cooling
4) Circulating cooling with water cooling or air cooling
d) Maximum and minimum cycle temperature
e) The highest and lowest available cooling water temperature
f) Analysis of cooling water (sediment, solid, salt)
g) Bearing shaft seal
h) Temperature sensing device (metal temperature or oil temperature)
i) Vibration monitoring device
A.3.3 The requirements for support and chassis are as follows.
a) Separate bearing support
b) Chassis installed on the foundation
A.3.4 The requirements for the casing and air intake box are as follows.
a) Special materials and minimal instrumentation.
b) The flange is connected to the pipe network with bolts or sealed welding.
c) Drain holes on the casing and air box.
d) Special shaft seal.
e) Protection against wear and corrosion.
f) The orientation, rotation and exhaust direction of the air intake box.
A.3.5 The coupling requirements are as follows.
a) Type of coupling
b) Guard for special coupling
A.3.6 The muffler requirements are as follows.
a) Imported muffler
b) Exit muffler
c) Muffler of the cabinet
A.3.7 The requirements for cleaning the impeller device are as follows.
a) The cleaning medium requirements are as follows.
1) Air
2) Steam
3) water
b) The pressure and temperature of the cleaning medium that can be used
A.3.8 Requirements for special coatings
A.4 Sound power level requirements
Appendix B
(Informative appendix)
Necessary information for evaluating fan design
B.1 Description
B.1.1 Generally, the design of a wind turbine includes rated parameters and corresponding performance curves (see Figure B1), as well as the main aspects of the structure
Detailed information. This appendix contains tables for the normal calculation of the minimum information required for a fan to compare with other fans.
Figure B.1 Recommended performance curve
B.1.2 In the performance curve of the fan, at least the following information should be included.
-specification
-Diameter of impeller
-model
-Rotating speed
-Import density
-Fan inlet area (plane 1)
-Fan outlet area (plane 2)
-Adjustment method
-Adjust the position corresponding to the performance parameter (ie a, b, c, d)
-Typical layout
-Describe which ancillary equipment losses have been included in the performance parameters and their magnitudes (regulating doors, mufflers, etc.)
Related standard:   DL/T 341-2019  DL/T 345-2019
   
 
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