Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009 Directives for standardization - Part 1: Structure and drafting of standards.
Attention is drawn to the possibility that some of the elements of this standard may be the subject of patent rights. The issuing authority of this standard shall not be held responsible for identifying any or all such patent rights.
This standard replaces DL/T 468-2004 Guide on type selection and application for power boiler fans. In addition to editorial changes, the following main technical changes have been made with respect to DL/T 468-2004:
——The definitions of forced draft fan and induced draft fan in clause 3 have been modified;
——The definition of stall safety factor of axial flow fan has been added in clause 3;
——The definitions of base flow, base pressure and test block have been added in clause 3;
——The title of clause 4 has been changed as design requirements of fan;
——The relevant contents on the requirements of fan manufacturing in clause 4 have been deleted;
——The title of clause 5 has been changed as type selection of fans;
——The requirements for original data ought to be provided for fan selection have been given in clause 5;
——The requirements on the selection of fan rotating speed in clause 5 have been modified;
——The requirements on selection of number of fans in clause 5 have been modified;
——The requirements on fan adjustment method in clause 5 have been modified;
——The requirements on stall safety factor of axial flow fan in clause have been modified;
——The clause 6 "Installation of fan" in the original standard has been deleted;
——The serial number of clause 7 of the original standard has been revised to 6, and the serial numbers of subsequent clauses and subclauses has been revised accordingly;
——The requirements on operating parameter control in clause 6 “Fan operation” have been modified.
This standard was proposed by the China Electricity Council.
This standard is under the jurisdiction of DL/TC 08 Technical Committee on Power Station Boiler of Standardization Administration of Power Industry.
The previous editions of this standard are as follows:
——DL/T 468-1992;
——DL/T 468-2004.
Any comments or suggestions during the implementation of this standard may be fed back to the Standardization Center of the China Electricity Council (No.1, 2nd Lane, Baiguang Road, Beijing, 100761, China).
Guide to selection and application of boiler fans for power plants
1 Scope
This standard specifies the basic requirements for the selection and application of boiler fans for power plants as well as for arrangement and design of inlet and outlet pipelines of fans.
This standard is applicable to forced draft fan, induced draft fan, primary fan, exhauster (pulverized coal fan), flue-gas recirculating fan, booster fan of flue gas desulfurization device and seal air fan for coal mill. Reference may be made to this standard for other small fans for boilers, such as ignition fan, cooling fan and dilution fan of SCR denitration system.
This standard is not applicable to oxidation fans of desulfurization systems and high-pressure fluidization fans of circulating fluidized bed boilers.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1236 Industrial fans - Performance testing using standardized airways
GB/T 2888 Methods of noise measurement for fans blowers compressors and roots blowers
GB/T 3235 Basic types sizes parameters and characteristics curve of fans
GB/T 3947 Acoustical terminology
GB/T 10178 Industrial fans - Performance testing in situ
GB/T 17774 Industrial fans - Dimensions
GB/T 19075 Industrial fans - Vocabulary and definitions of categories
GB 50660 Code for design of fossil fired power plant
DL/T 469 Fans performance testing in situ for power boiler
DL/T 5121 Technical code for design of thermal power plant air & flue gas ducts/ raw coal & pulverized coal piping
DL/T 5145 Technical code for design and calculations of coal pulverizing system of fossil-fired power plant
DL 5190.2 Technical specification for thermal power erection and construction - Part 2: boiler unit
JB/T 4358 Centrifugal fan for boiler of power station
JB/T 4362 Power station axial fans
JB/T 6891 Technical specification for silencer of fan
JB/T 8689 Fan vibration detection and its limited value
JB/T 8690 Industrial fans noise limited value
JB/T 8822 High temperature centrifugal fan - Specification
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
forced draft fan; FDF
fan that supplies air needed for boiler fuel combustion and is arranged in front of the boiler air preheater, which sends the air sucked from the atmosphere to the air preheater to heat it to the design temperature, then, for direct-fired pulverizing system, sends the air directly into the boiler furnace through the burner as the secondary air of the boiler and, for the middle storage pulverizing system, sends one part of the air directly into the boiler furnace through the burner as the secondary air of the boiler and the other part of the air into pulverized coal preparation system as desiccant or into furnace as primary air conveying the pulverized coal through burner (exhaust gas pulverized coal feeding system) or into furnace as tertiary air through the burner (hot air pulverized coal feeding system); large boilers adopting medium speed coal mills or double-inlet and double-outlet low speed coal mill positive pressure direct-fired pulverizing system are all equipped with high-pressure cold primary fans which either draw air from the outlet of the forced draft fan which supplies the total air volume required by the boiler or draw air from the atmosphere, in which case the forced draft fan only supplies the secondary air to the boiler, which is also called the secondary air fan.
3.2
induced draft fan; IDF
fan installed behind the boiler dust remover, sucking out the boiler combustion products (flue gas) from the boiler tail and sending to the booster fan of the desulfurization system after passing through the denitration system and dust removal system and, after the flue gas pressure is raised by the booster fan, discharging the flue gas into the atmosphere from the chimney through desulfurization system, also known as the suction fan, which shall overcome the resistance of the whole flue gas system from boiler furnace to chimney outlet if there is no booster fan, in which case it is commonly known as 2-in-1 induced draft fan
3.3
primary fan; PF
fan that supplies primary air needed for boiler fuel combustion, which is classified by its installation position in the system into cold primary fan and hot primary fan
3.4
cold primary fan
primary fan installed in front of the boiler air preheater and sending the air sucked from the atmosphere or from the outlet cold air duct of the forced draft fan into pulverizing system after being heated by the air preheater
3.5
hot primary fan
primary fan which is installed behind the boiler air preheater and sends the air heated by the boiler air preheater to direct-fired pulverizing system or sends only the pulverized coal to the boiler
3.6
exhauster
fan for conveying desiccant and pulverized coal in pulverized coal preparation system, which is mainly used in the middle storage pulverizing system and installed behind the fine powder separator, also known as pulverized coal fan
3.7
flue-gas recirculating fan
fan sucking out part of the flue gas from the backside of the economizer and front of the air preheater, the lower part of furnace, the backside of the electrical precipitator, the outlet of induced draft fan, etc., and delivering to the boiler cold ash hopper or the upper part of furnace to adjust the boiler steam temperature or delivering to the coal mill inlet to adjust the temperature or oxygen content
3.8
flue gas desulfurization booster fan
fan set behind the induced draft fan to overcome the resistance of the flue gas desulfurization system
3.9
seal air fan
fan for supplying sealing air for medium speed coal mill, double-inlet and double-outlet low speed coal mill and coal feeder, which may suck air directly from the atmosphere, and may also suck air from the outlet pipeline of forced draft fan or primary fan
3.10
inlet plane and inlet area of fan
A1
fan inlet plane referring to the surface bounded by the upstream extremity of the air moving device, and generally, fan inlet area referring to the total through-flow area of the inlet (flange) plane of the enclosure (or the inlet box in the case of fans with inlet box)
3.11
outlet plane and outlet area of fan
A2
fan outlet plane referring to the surface bounded by the downstream extremity of the air moving device, and generally, fan outlet area referring to the total area of the plane of the enclosure outlet (flange)
3.12
stall safety factor of axial flow fans
vector indicating the stall margin of axial flow fan in this standard, which is expressed by k (see 5.4.4 of this standard)
3.13
fan system
system consisting of fan, equipment as well as a series of air duct, pipe, bend and branch pipe on the conveying path for conveying air or gas from one or more places to another one or more places
3.14
system characteristic curves
diagram for resistance versus volumetric flow characteristics of a system
3.15
system effect
influence of system layout on fan performance which is affected by the inlet and outlet connection pipes which, if connected improperly, together with uneven airflow at the inlet and vortex at the inlet of the fan, will change the aerodynamic characteristics of the fan and reduce the performance of the fan
3.16
system effect loss
reduction of fan pressure caused by system effect
3.17
base flow
fan flow required for operation at the boiler maximum continuous rating calculated according to the design coal type
3.18
base pressure
total resistance of fan system when operating at the boiler maximum continuous rating calculated according to the design coal type
3.19
test block
maximum continuous operation condition of the fan required for type selection
3.20
specific A sound level; LSA
A sound level at unit flow rate and unit fan pressure, which shall be calculated using Equation (1):
(1)
where,
LSA——the specific A sound level, dB(A);
LA——the A sound level, dB (A);
qV——the volumetric flow rate, m3/min;
pF——the fan pressure, Pa.
4 Design requirements of fans
4.1 General requirements
4.1.1 The design of fans shall meet the requirements of GB/T 3235 and GB/T 17774.
4.1.2 The design and manufacture of centrifugal fans shall meet those specified in JB/T 4358.
4.1.3 The design and manufacture of axial flow fans shall meet those specified in JB/T 4362.
4.1.4 The natural vibration frequency of the fan impeller (or blade) shall not be the same as the rotating speed frequency of the impeller and the frequency multiplication less than 10 times of it, or other dangerous frequencies, such as the blade passing frequency, i.e., the product of the rotating speed (for fans with rotating speed regulation, it refers to all the rotating speeds within the regulation range) and the number of blades (includes rotor blades and front and rear adjustable or guide blades for impellers), and high amplitude air motion frequency.
4.1.5 For fans with variable speed adjustment, calculations on torsional vibration of shafting shall be conducted to prevent it from occurring.
4.1.6 The fan shall be equipped with necessary automatic alarm and protection devices (such as those for bearing temperature, fuel cut-off, vibration, and stall flutter of axial flow fan).
4.1.7 Fans with air intake from the atmosphere (such as forced draft fans and primary fans) shall be equipped with an air inlet silencer that is designed and manufactured in accordance with JB/T 6891.
4.2 Design requirements
4.2.1 For hot primary fan, the design inlet air temperature shall be 250℃, the maximum allowable inlet air temperature shall not exceed 400℃ and the airborne dust concentration shall not exceed 100mg/m3. The design of it shall comply with those specified in 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 around 90℃, at which the flue gas is corrosive, so reliable anti-corrosion measures shall be taken in the flow path of the fan.
4.2.3 The exhauster (pulverized coal fan) is designed to convey air containing pulverized coal. The pulverized coal content shall not be greater than 80g/m3 for the exhaust gas from middle storage pulverizing system of low speed coal mill, and it shall be 300g/m3~800g/m3 for negative-pressure direct-fired pulverizing system. The design inlet gas temperature and the maximum allowable inlet gas temperature shall be 70℃ and 150℃, respectively. The enclosure and impeller shall be protected from wear according to the wear characteristics of the coal (see DL/T 5145 for the wear indexes), and the service life of the impeller shall not be less than 8,000h.
4.2.4 The flue-gas recirculating fan is designed to convey hot flue gas with an ash content no greater than 20g/m3 and a temperature no higher than 400℃. The volute and impeller shall be properly protected from wear. The bearings shall be equipped with special heat insulation and cooling devices, and their service life shall not be less than 8,000h. Flue-gas recirculating fan without speed adjusting device shall be equipped with a turning device.
4.2.5 Noise countermeasures shall be taken in the design of seal air fan. Seal air fans with direct air intake from the atmosphere shall be equipped with inlet filters and inlet and outlet silencers.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Design requirements of fans 5 Type selection of fans 6 Fan operation 7 Fan noise 8 Test and acceptance of fan 9 Fan system design Annex A (Informative) Necessary information on selection of fan Annex B (Informative) Necessary information for evaluation of fan design Annex C (Informative) Calculation of standard density of humid air
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009 Directives for standardization - Part 1: Structure and drafting of standards.
Attention is drawn to the possibility that some of the elements of this standard may be the subject of patent rights. The issuing authority of this standard shall not be held responsible for identifying any or all such patent rights.
This standard replaces DL/T 468-2004 Guide on type selection and application for power boiler fans. In addition to editorial changes, the following main technical changes have been made with respect to DL/T 468-2004:
——The definitions of forced draft fan and induced draft fan in clause 3 have been modified;
——The definition of stall safety factor of axial flow fan has been added in clause 3;
——The definitions of base flow, base pressure and test block have been added in clause 3;
——The title of clause 4 has been changed as design requirements of fan;
——The relevant contents on the requirements of fan manufacturing in clause 4 have been deleted;
——The title of clause 5 has been changed as type selection of fans;
——The requirements for original data ought to be provided for fan selection have been given in clause 5;
——The requirements on the selection of fan rotating speed in clause 5 have been modified;
——The requirements on selection of number of fans in clause 5 have been modified;
——The requirements on fan adjustment method in clause 5 have been modified;
——The requirements on stall safety factor of axial flow fan in clause have been modified;
——The clause 6 "Installation of fan" in the original standard has been deleted;
——The serial number of clause 7 of the original standard has been revised to 6, and the serial numbers of subsequent clauses and subclauses has been revised accordingly;
——The requirements on operating parameter control in clause 6 “Fan operation” have been modified.
This standard was proposed by the China Electricity Council.
This standard is under the jurisdiction of DL/TC 08 Technical Committee on Power Station Boiler of Standardization Administration of Power Industry.
The previous editions of this standard are as follows:
——DL/T 468-1992;
——DL/T 468-2004.
Any comments or suggestions during the implementation of this standard may be fed back to the Standardization Center of the China Electricity Council (No.1, 2nd Lane, Baiguang Road, Beijing, 100761, China).
Guide to selection and application of boiler fans for power plants
1 Scope
This standard specifies the basic requirements for the selection and application of boiler fans for power plants as well as for arrangement and design of inlet and outlet pipelines of fans.
This standard is applicable to forced draft fan, induced draft fan, primary fan, exhauster (pulverized coal fan), flue-gas recirculating fan, booster fan of flue gas desulfurization device and seal air fan for coal mill. Reference may be made to this standard for other small fans for boilers, such as ignition fan, cooling fan and dilution fan of SCR denitration system.
This standard is not applicable to oxidation fans of desulfurization systems and high-pressure fluidization fans of circulating fluidized bed boilers.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1236 Industrial fans - Performance testing using standardized airways
GB/T 2888 Methods of noise measurement for fans blowers compressors and roots blowers
GB/T 3235 Basic types sizes parameters and characteristics curve of fans
GB/T 3947 Acoustical terminology
GB/T 10178 Industrial fans - Performance testing in situ
GB/T 17774 Industrial fans - Dimensions
GB/T 19075 Industrial fans - Vocabulary and definitions of categories
GB 50660 Code for design of fossil fired power plant
DL/T 469 Fans performance testing in situ for power boiler
DL/T 5121 Technical code for design of thermal power plant air & flue gas ducts/ raw coal & pulverized coal piping
DL/T 5145 Technical code for design and calculations of coal pulverizing system of fossil-fired power plant
DL 5190.2 Technical specification for thermal power erection and construction - Part 2: boiler unit
JB/T 4358 Centrifugal fan for boiler of power station
JB/T 4362 Power station axial fans
JB/T 6891 Technical specification for silencer of fan
JB/T 8689 Fan vibration detection and its limited value
JB/T 8690 Industrial fans noise limited value
JB/T 8822 High temperature centrifugal fan - Specification
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
forced draft fan; FDF
fan that supplies air needed for boiler fuel combustion and is arranged in front of the boiler air preheater, which sends the air sucked from the atmosphere to the air preheater to heat it to the design temperature, then, for direct-fired pulverizing system, sends the air directly into the boiler furnace through the burner as the secondary air of the boiler and, for the middle storage pulverizing system, sends one part of the air directly into the boiler furnace through the burner as the secondary air of the boiler and the other part of the air into pulverized coal preparation system as desiccant or into furnace as primary air conveying the pulverized coal through burner (exhaust gas pulverized coal feeding system) or into furnace as tertiary air through the burner (hot air pulverized coal feeding system); large boilers adopting medium speed coal mills or double-inlet and double-outlet low speed coal mill positive pressure direct-fired pulverizing system are all equipped with high-pressure cold primary fans which either draw air from the outlet of the forced draft fan which supplies the total air volume required by the boiler or draw air from the atmosphere, in which case the forced draft fan only supplies the secondary air to the boiler, which is also called the secondary air fan.
3.2
induced draft fan; IDF
fan installed behind the boiler dust remover, sucking out the boiler combustion products (flue gas) from the boiler tail and sending to the booster fan of the desulfurization system after passing through the denitration system and dust removal system and, after the flue gas pressure is raised by the booster fan, discharging the flue gas into the atmosphere from the chimney through desulfurization system, also known as the suction fan, which shall overcome the resistance of the whole flue gas system from boiler furnace to chimney outlet if there is no booster fan, in which case it is commonly known as 2-in-1 induced draft fan
3.3
primary fan; PF
fan that supplies primary air needed for boiler fuel combustion, which is classified by its installation position in the system into cold primary fan and hot primary fan
3.4
cold primary fan
primary fan installed in front of the boiler air preheater and sending the air sucked from the atmosphere or from the outlet cold air duct of the forced draft fan into pulverizing system after being heated by the air preheater
3.5
hot primary fan
primary fan which is installed behind the boiler air preheater and sends the air heated by the boiler air preheater to direct-fired pulverizing system or sends only the pulverized coal to the boiler
3.6
exhauster
fan for conveying desiccant and pulverized coal in pulverized coal preparation system, which is mainly used in the middle storage pulverizing system and installed behind the fine powder separator, also known as pulverized coal fan
3.7
flue-gas recirculating fan
fan sucking out part of the flue gas from the backside of the economizer and front of the air preheater, the lower part of furnace, the backside of the electrical precipitator, the outlet of induced draft fan, etc., and delivering to the boiler cold ash hopper or the upper part of furnace to adjust the boiler steam temperature or delivering to the coal mill inlet to adjust the temperature or oxygen content
3.8
flue gas desulfurization booster fan
fan set behind the induced draft fan to overcome the resistance of the flue gas desulfurization system
3.9
seal air fan
fan for supplying sealing air for medium speed coal mill, double-inlet and double-outlet low speed coal mill and coal feeder, which may suck air directly from the atmosphere, and may also suck air from the outlet pipeline of forced draft fan or primary fan
3.10
inlet plane and inlet area of fan
A1
fan inlet plane referring to the surface bounded by the upstream extremity of the air moving device, and generally, fan inlet area referring to the total through-flow area of the inlet (flange) plane of the enclosure (or the inlet box in the case of fans with inlet box)
3.11
outlet plane and outlet area of fan
A2
fan outlet plane referring to the surface bounded by the downstream extremity of the air moving device, and generally, fan outlet area referring to the total area of the plane of the enclosure outlet (flange)
3.12
stall safety factor of axial flow fans
vector indicating the stall margin of axial flow fan in this standard, which is expressed by k (see 5.4.4 of this standard)
3.13
fan system
system consisting of fan, equipment as well as a series of air duct, pipe, bend and branch pipe on the conveying path for conveying air or gas from one or more places to another one or more places
3.14
system characteristic curves
diagram for resistance versus volumetric flow characteristics of a system
3.15
system effect
influence of system layout on fan performance which is affected by the inlet and outlet connection pipes which, if connected improperly, together with uneven airflow at the inlet and vortex at the inlet of the fan, will change the aerodynamic characteristics of the fan and reduce the performance of the fan
3.16
system effect loss
reduction of fan pressure caused by system effect
3.17
base flow
fan flow required for operation at the boiler maximum continuous rating calculated according to the design coal type
3.18
base pressure
total resistance of fan system when operating at the boiler maximum continuous rating calculated according to the design coal type
3.19
test block
maximum continuous operation condition of the fan required for type selection
3.20
specific A sound level; LSA
A sound level at unit flow rate and unit fan pressure, which shall be calculated using Equation (1):
(1)
where,
LSA——the specific A sound level, dB(A);
LA——the A sound level, dB (A);
qV——the volumetric flow rate, m3/min;
pF——the fan pressure, Pa.
4 Design requirements of fans
4.1 General requirements
4.1.1 The design of fans shall meet the requirements of GB/T 3235 and GB/T 17774.
4.1.2 The design and manufacture of centrifugal fans shall meet those specified in JB/T 4358.
4.1.3 The design and manufacture of axial flow fans shall meet those specified in JB/T 4362.
4.1.4 The natural vibration frequency of the fan impeller (or blade) shall not be the same as the rotating speed frequency of the impeller and the frequency multiplication less than 10 times of it, or other dangerous frequencies, such as the blade passing frequency, i.e., the product of the rotating speed (for fans with rotating speed regulation, it refers to all the rotating speeds within the regulation range) and the number of blades (includes rotor blades and front and rear adjustable or guide blades for impellers), and high amplitude air motion frequency.
4.1.5 For fans with variable speed adjustment, calculations on torsional vibration of shafting shall be conducted to prevent it from occurring.
4.1.6 The fan shall be equipped with necessary automatic alarm and protection devices (such as those for bearing temperature, fuel cut-off, vibration, and stall flutter of axial flow fan).
4.1.7 Fans with air intake from the atmosphere (such as forced draft fans and primary fans) shall be equipped with an air inlet silencer that is designed and manufactured in accordance with JB/T 6891.
4.2 Design requirements
4.2.1 For hot primary fan, the design inlet air temperature shall be 250℃, the maximum allowable inlet air temperature shall not exceed 400℃ and the airborne dust concentration shall not exceed 100mg/m3. The design of it shall comply with those specified in 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 around 90℃, at which the flue gas is corrosive, so reliable anti-corrosion measures shall be taken in the flow path of the fan.
4.2.3 The exhauster (pulverized coal fan) is designed to convey air containing pulverized coal. The pulverized coal content shall not be greater than 80g/m3 for the exhaust gas from middle storage pulverizing system of low speed coal mill, and it shall be 300g/m3~800g/m3 for negative-pressure direct-fired pulverizing system. The design inlet gas temperature and the maximum allowable inlet gas temperature shall be 70℃ and 150℃, respectively. The enclosure and impeller shall be protected from wear according to the wear characteristics of the coal (see DL/T 5145 for the wear indexes), and the service life of the impeller shall not be less than 8,000h.
4.2.4 The flue-gas recirculating fan is designed to convey hot flue gas with an ash content no greater than 20g/m3 and a temperature no higher than 400℃. The volute and impeller shall be properly protected from wear. The bearings shall be equipped with special heat insulation and cooling devices, and their service life shall not be less than 8,000h. Flue-gas recirculating fan without speed adjusting device shall be equipped with a turning device.
4.2.5 Noise countermeasures shall be taken in the design of seal air fan. Seal air fans with direct air intake from the atmosphere shall be equipped with inlet filters and inlet and outlet silencers.
Contents of DL/T 468-2019
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Design requirements of fans
5 Type selection of fans
6 Fan operation
7 Fan noise
8 Test and acceptance of fan
9 Fan system design
Annex A (Informative) Necessary information on selection of fan
Annex B (Informative) Necessary information for evaluation of fan design
Annex C (Informative) Calculation of standard density of humid air
