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
電站鍋爐風機選型和使用導則
1 范圍
本標準規定了電站鍋爐風機的選型、使用及風機進出口管道布置設計的基本要求。
本標準適用于電站鍋爐的送風機、引風機、一次風機、排粉風機(煤粉風機)、煙氣再循環風機、煙氣脫硫裝置的增壓風機和磨煤機用的密封風機。其他供鍋爐用的小型風機如點火風機、冷卻風機、SCR脫硝系統的稀釋風機等可參照使用。
本標準不適用于脫硫系統的氧化風機和循環流化床鍋爐的高壓流化風機。
2 規范性引用文件
下列文件對于本文件的應用是必不可少的。凡是注日期的引用文件，僅注日期的版本適用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改單)適用于本文件。
GB／T 1236 工業通風機 用標準化風道進行性能試驗
GB／T 2888 風機和羅茨鼓風機噪聲測量方法
GB／T 3235 通風機基本型式、尺寸參數及性能曲線
GB／T 3947 聲學名詞術語
GB／T 10178 工業通風機 現場性能試驗
GB／T 17774 工業通風機 尺寸
GB／T 19075 工業通風機 詞匯及種類定義
GB 50660 大中型火力發電廠設計規范
DL／T 469 電站鍋爐風機現場性能試驗
DL／T5121 火力發電廠煙風煤粉管道設計技術規程
DL／T5145 火力發電廠制粉系統設計計算技術規定
DL5190.2 電力建設施工技術規范 第2部分：鍋爐機組
JB／T 4358 電站鍋爐離心式通風機
JB／T 4362 電站軸流式通風機
JB／T 6891 風機用消聲器技術條件
JB／T 8689 通風機振動檢測及其限值
JB／T 8690 工業通風機 噪聲限值
JB／T 8822 高溫離心通風機技術條件
3 術語和定義
下列術語和定義適用于本文件。
3.1
送風機forced draft fan；FDF
供給鍋爐燃料燃燒所需空氣的風機。布置在鍋爐空氣預熱器之前。將從大氣中吸入的空氣送入空氣預熱器，加熱到設計溫度后，對于直吹式制粉系統，作為鍋爐的二次風，直接經燃燒器送入鍋爐爐膛。對于中間倉儲式制粉系統，則一部分作為鍋爐的二次風，直接經燃燒器送入鍋爐爐膛；另一部分進入煤粉制備系統作為干燥劑，或作為一次風輸送煤粉經燃燒器送入爐膛(乏氣送粉系統)，或作為三次風經燃燒器送入爐膛(熱風送粉系統)。大型鍋爐采用中速磨煤機或雙進雙出鋼球磨煤機正壓直吹式制粉系統，均配有高壓冷一次風機。一次風機有從送風機出口吸取空氣的，則送風機供給鍋爐所需的總風量；也有專門從大氣吸入空氣的，此時送風機只供給鍋爐的二次風，亦稱二次風機。
3.2
引風機 induced draft fan；IDF
安裝在鍋爐除塵器之后，將鍋爐燃燒產物(煙氣)從鍋爐尾部吸出并經脫硝系統、除塵系統后送入脫硫系統的增壓風機，提升壓力后再經脫硫系統由煙囪排入大氣的風機，又稱吸風機。如不設增壓風機，則從鍋爐爐膛到煙囪出口整個煙氣系統的阻力均由引風機克服(俗稱二合一引風機)。
3.3
一次風機 primary fan：PF
供給鍋爐燃料燃燒所需一次空氣的風機。按其在系統中的安裝位置，有冷一次風機和熱一次風機之分。
3.4
冷一次風機 cold primary fan
安裝在鍋爐空氣預熱器之前，將從大氣或從送風機出口冷風道抽吸的空氣經空氣預熱器加熱后輸送至制粉系統的一次風機。
3.5
熱一次風機 hot primary fan
安裝在鍋爐空氣預熱器之后，輸送經過鍋爐空氣預熱器加熱后的熱空氣至直吹式制粉系統或僅輸送煤粉至鍋爐的一次風機。
3.6
排粉風機 exhauster
煤粉制備系統中用以輸送干燥劑和煤粉的風機。主要用于中間儲倉式制粉系統中，安裝在細粉分離器之后。也稱煤粉風機。
3.7
煙氣再循環風機 flue-gas recirculating fan
把一部分煙氣從省煤器后空氣預熱器前、爐膛下部、電除塵器后、引風機出口等處抽出，并輸送至鍋爐冷灰斗或爐膛上部，用以調節鍋爐蒸汽溫度；或送至磨煤機入口用以調節溫度或含氧量的風機。
3.8
煙氣脫硫增壓風機 flue gas desulfurization booster fan
在引風機后設置的用以克服煙氣脫硫系統阻力的風機。
3.9
密封風機 seal air fan
供給中速磨煤機、雙進雙出鋼球磨煤機和給煤機等裝置密封用空氣的風機。密封風機可直接從大氣吸入空氣，也可從送風機或一次風機出口管道內吸取空氣。
3.10
風機進口平面和進口面積 inlet plane and inlet area of fan
A1
取空氣輸送裝置上游末端的界面為風機進口平面。通常，取機殼(帶進氣箱的風機取進氣箱)進口(法蘭)平面的通流總面積作為風機進口面積。
3.11
風機出口平面和出口面積 outlet plane and outlet area of fan
A2
取空氣輸送裝置下游段始端的界面為風機出口平面。通常，取機殼出口(法蘭)平面的總面積作為風機出口面積。
3.12
軸流式風機失速安全系數 stall safety factor of axial flow fans
本標準表示軸流式風機失速裕度的量，用k表示(見本標準5.4.4)。
3.13
風機系統 fan system
為從一處或多處向另一處或多處輸送空氣或氣體而由風機和輸送路徑上的各設備及一系列風筒、管路、彎管和支管所組成的系統。
3.14
系統特性曲線 system characteristic curves
某個系統的阻力對容積流量特性的圖解。
3.15
系統效應 system effect
系統布置對風機性能的影響。風機的性能受其進、出口連接管道的影響。如果連接不當、進口氣流不均勻，以及風機進口處存在渦流，則將改變風機的空氣動力特性，降低風機的性能。
3.16
系統效應損失 system effect loss
由系統效應引起的風機壓力的降低。
3.17
基本風量 base flow
按設計煤種計算的鍋爐最大連續蒸發量運行所需的風機流量。
3.18
基本壓力 base pressure
按設計煤種計算的鍋爐最大連續蒸發量運行時的風機系統總阻力。
3.19
選型工況(TB工況) test block
選型要求風機應達到的最大連續運行工況。
3.20
比A聲級 specific A sound level；LSA
單位流量、單位風機壓力時的A聲級。比A聲級按式(1)計算：
(1)
式中：
LSA——比A聲級，dB(A)；
LA——A聲級，dB(A)；
qV——體積流量，m3／min；
pF——風機壓力，Pa。
4 風機的設計要求
4.1 總體要求
4.1.1 風機的設計應符合GB／T 3235及GB／T 17774的要求。
4.1.2 離心式風機的設計制造應符合JB／T 4358的規定。
4.1.3 軸流式風機的設計制造應符合JB／T 4362的規定。
4.1.4 風機葉輪(或葉片)的自振頻率應避開葉輪的轉速頻率及其10倍以下倍頻和其他危險頻率，如葉片通過頻率即轉速(采用轉速調節的風機包括轉速調節范圍內的所有轉速)與葉片數(包括轉子葉片和葉輪前后調節或導向葉片)的乘積、高幅值的氣流脈動頻率等。
4.1.5 采用變速調節的風機，應進行軸系扭轉振動計算，防止軸系發生扭轉振動。
4.1.6 風機應設有必要的自動報警和保護裝置(如軸承溫度、斷油、振動和軸流式風機的失速喘振等)。
4.1.7 自大氣吸氣的風機(如送風機、一次風機)應配備進口消聲器，消聲器的設計和制造應符合JB／T 6891的規定。
4.2 設計要求
4.2.1 熱一次風機的設計進口空氣溫度為250℃，允許最高進口空氣溫度不超過400℃，空氣的含塵濃度不超過100mg／m3。其設計應符合JB／T 8822的規定。
4.2.2 引風機上游煙氣系統配備有低溫省煤器的系統，引風機入口溫度在90℃左右，具有腐蝕性，在風機的通流部分應采取可靠的防腐措施。
4.2.3 排粉風機(煤粉風機)設計要求輸送的介質是含煤粉的空氣。其含煤粉量，對于鋼球磨煤機中間儲倉式制粉系統的乏氣不大于80g／m3，對于負壓直吹式制粉系統為300g／m3～800g／m3。其設計進口氣體溫度為70℃，允許最高進口氣體溫度為150℃。機殼和葉輪應根據煤的磨損特性(磨損指數的高低見DL／T 5145)采取防磨損措施，其葉輪的使用壽命不少于8000h。
4.2.4 煙氣再循環風機設計要求輸送的介質為含灰量不大于20g／m3、溫度不高于400℃的熱煙氣。其蝸殼和葉輪應采取適當的防磨損措施；軸承需設專門的隔熱和冷卻裝置，其使用壽命不得少于8000h。未配置調速裝置的煙氣再循環機應設置盤車裝置。
4.2.5 密封風機的設計應采取消聲措施。對從大氣直接吸氣的密封風機，應配備進口過濾器和進、出口消聲器。
5 風機的選型
5.1 選擇風機應提供的原始數據
選擇風機應提供的原始數據至少包括：
a) 當地大氣條件：
1) 大氣壓力；
2) 干、濕空氣溫度；
3) 空氣相對濕度。
b) 鍋爐熱力計算和空氣動力計算結果。
c) 鍋爐各典型工況下的風機參數：
1) 流量(風量、煙氣量)；
2) 風機進口側系統總阻力(即風機進口全壓)和與之對應的風機進口風道截面動壓；
3) 風機出口側系統總阻力(即風機出口全壓)；
4) 風(煙)系統總阻力(即風機壓力，以往稱風機全壓)；
5) 介質溫度；
6) 介質標準密度(空氣介質為當地濕空氣的標準密度；煙氣介質為風機進口濕煙氣的標準密度)。
注：各典型工況包括：
——選型工況(TB)；
——BMCR工況；
——BRL工況；
——THA工況；
——75％THA工況；
——50％THA工況；
——不投油最低穩燃工況。
d) 機組在不同負荷下年運行小時數。
5.2 風機選型參數的確定
5.2.1 基本風量按照以下要求確定：
a) 對于新建鍋爐的風機，基本風量按GB 50660的相關規定確定。
b) 對于改造已投運的風機，其基本風量需由現場試驗確定。試驗工況不少于三個(在機組高、中、低三個負荷下進行)，并將試驗結果換算至鍋爐最大連續蒸發量(BMCR)工況下的流量。
5.2.2 基本風壓按照以下要求確定：
a) 對于新建鍋爐的風機，其基本風壓按GB 50660的相關規定進行計算，計算所得的風機系統阻力宜參考同類型機組的實際運行值確定是否需進行調整。
b) 對于改造已投運的風機，其基本風壓由現場試驗確定(風壓試驗應與流量試驗同時進行，并通過DCS對系統內各主要設備及有關管道的阻力進行采集)。必要時，進行測量和／或通過SIS采集近一年內機組滿負荷時風機進、出口壓力值予以核對。應同時考慮風機對應系統(包括系統中的其他設備)的改造引起的阻力變化，并將換算至鍋爐最大連續蒸發量(BMCR)下的系統總阻力確定為風機選型的基本風壓。
5.2.3 風量、風壓裕量按照以下要求選取：
a) 對于新建鍋爐的風機，流量與壓力的裕量宜根據GB 50660的相關規定選取。
b) 改造已投運的風機，風機流量、壓力裕量，宜在考慮改造前試驗時的氣候條件與當地夏、冬兩季差異、鍋爐設備及煙風系統運行狀況，以及機組負荷系數及煤質變化范圍等因素的基礎上確定：也可參照GB 50660的規定選取。
5.3 風機轉速、臺數及型式的選擇
5.3.1 風機轉速的選擇，一般情況下，一次風機宜選用4極電動機(1490r／min)；送風機宜選用4極或6極電動機(1490r／min或990r／min)；引風機和脫硫增壓風機的轉速宜選用6極以下電動機(即最高990r／min)，對于變轉速調節的引、增壓風機合一的靜葉調節軸流式引風機，根據參數需要可選取高于990r／min的轉速，但需滿足結構強度及剛度可靠的要求。
5.3.2 風機臺數的選擇按照以下要求進行：
a) 對50MW及以上機組，鍋爐風機臺數宜符合GB 50660的相關規定(送風機、引風機、冷一次風機每爐宜各設置2臺：增壓風機臺數宜與脫硫裝置臺數相同：排粉機臺數應與磨煤機臺數相同；制粉系統密封風機每爐設置2臺，一運一備)。
b) 對25MW級機組配套的鍋爐應裝設1臺送風機和2臺引風機，但燃油燃氣負壓鍋爐應裝設1臺送風機和1臺引風機。
c) 對12MW級及以下機組配套的鍋爐應裝設1臺送風機和1臺引風機。
d) 對50MW～600MW級機組，經技術經濟論證和可靠性論證可行者，可采用每臺鍋爐僅設置1臺送風機、1臺引風機和1臺一次風機。
e) 視布置條件和機組設計負荷率情況，經技術經濟論證可行時，引風機也可設置3臺～4臺。
5.3.3 風機型式的選擇按TB工況參數和選取的風機轉速計算出所需風機的比轉速，然后選取比轉速最接近的風機型式。對于給定的參數，當可以選擇幾種不同型式的風機時，應根據鍋爐機組的年負荷曲線、風機耗電、調節效率、設備造價、維護費用及其他因素進行綜合技術經濟比較來選擇。不同類型風機比轉速參考范圍見表1。
表1 不同類型風機比轉速參考范圍
風機類型 比轉速
單吸離心式風機 18～94
雙吸離心式風機 25～120
靜葉調節子午加速軸流式風機 90～120
單級靜葉調節標準軸流式風機和動葉調節軸流式風機 100～200
雙級靜、動葉調節軸流式風機 59.5～119
5.4 風機型號的選擇
5.4.1 確定風機型號應遵循的原則如下：
a) 風機型式確定后，即可按相似設計方法確定風機型號，并應使系統阻力曲線完全落在所選風機性能曲線的穩定區域內，且失速裕度足夠。
b) 對于離心式風機，還應避開氣流高脈動區域。
c) 對于可選不同型式或型號的風機時，在滿足安全運行需要后，應根據機組負荷、利用小時數、設備費及年維護費等技術經濟指標確定風機的型號。
5.4.2 離心式風機型號的選擇應使選型工況點(即TB點)盡可能接近調節裝置最大開度時的流量-壓力曲線，并且位于風機最高效率的右側，其效率值不應低于風機最高效率的90％。
5.4.3 軸流式風機型號的選擇應在滿足風機選型工況點(即TB點)能安全可靠運行的前提下，應使發電機組在經濟負荷下(一般為發電機組額定出力)運行時，風機處于最高效率區運行。
5.4.4 軸流式風機選型時應確保有足夠的失速裕度，關于失速裕度(失速安全系數)的定義與要求如下：
a) 失速裕度可用失速安全系數k來表示，k由各設計工況點和對應開度下(動葉調節為動葉角度，靜葉調節為調節導葉角度)的失速工況點(或最大壓力點)的流量、壓力，并按式(2)計算得出：
(2)
式中：
p、q——各設計工況點的壓力和流量：
pk、qk——各失速工況點的壓力和流量。
b) 在選型設計時，各設計工況點k值宜大于1.35，即k＞1.35。
5.5 風機調節方式的選擇
5.5.1 對于動葉調節軸流式風機，當機組設計負荷系數低于70％，且設計轉速在1000r／min以下時，動葉調節軸流式風機宜選用雙速電動機變極數調節或選用變轉速裝置(變頻器、汽輪機驅動或其他變速裝置)調節，在機組較低負荷運行時切換或調節至低轉速運行。特別注意：動葉調節軸流式風機在選用變速的調節方式時，應取得制造廠對設備變速運行安全可靠性的保證。
5.5.2 對于靜葉調節軸流式風機，當機組設計負荷系數低于80％以下時，靜葉調節軸流式風機宜選用變轉速裝置(變頻器、汽輪機驅動或其他變速裝置)調節。
5.5.3 對于離心式風機，一般選擇入口導向器調節；為得到更佳的經濟性，宜選用雙速電動機變極數調節或變速裝置(變頻器、汽輪機驅動或其他變速裝置)調節。
5.5.4 對于排粉風機(一般為離心式)通常宜選擇入口節流門調節；也可選用入口調節門調節，但應對入口門采取相應的密封和防磨措施。
5.5.5 采用變轉速調節的風機，選用何種變速調節裝置及其調節范圍，應經過詳細的技術經濟比較來確定。
5.6 風機選型的基本資料
制造廠應提供的基本資料要求如下：
a) 風機選型的必要資料，參見附錄A。
b) 對各制造廠所選風機進行評定時，通常需要供應商提供的最少資料參見附錄B。
6 風機的運行
6.1 風機的運行區域
6.1.1 為避免高的氣流脈動對風機造成危害，離心式風機不應在可能引起喘振的不穩定區域內運行，也不應在氣流高脈動區域(如有)內運行，同時還應避免入口調節門開度在30％以下長期運行。
6.1.2 軸流式風機應避免所有可能的運行工況在失速區域(不穩定工況區域)內運行。
6.2 風機的并聯運行
6.2.1 兩臺風機并聯運行時系統工作點是由每臺風機各自運行點綜合而成。若一臺風機停止運行，則另一臺風機運行點將根據系統阻力特性的需要進行匹配。
6.2.2 對于離心式前彎風機，在停運一臺風機時需注意監視風機的電流，以防電動機超載。
6.2.3 對于軸流式風機，單臺風機的最大出力取決于動葉(或靜葉)的最大運行角度和電動機容量。當要啟動停用的風機時，其隔離門宜關閉，葉片角度(動葉調節為動葉角度，靜葉調節為調節導葉角度)宜調至最小，當風機達到全速后，隔離門打開。在任何情況下，當第一臺風機運行時的壓力高于第二臺風機失速界線的最低點壓力時，不應啟動第二臺風機進行并聯。如需并聯，則應降低第一臺風機的出力，使其運行點的降低至第二臺失速界限壓力后再啟動第二臺風機進行并聯。
6.2.4 停用的風機再次啟動時，該風機的隔離門和入口調節門均宜關閉，以減少啟動阻力矩和啟動時間。如果由于上述風門的泄漏而造成風機在啟動前反轉時，啟動應特別謹慎(大型離心式風機特別是引風機宜配備制動或盤車裝置)，以防止啟動時間過長而損壞電動機。通常，無調速和軟啟動設備的風機啟動時間應限制在25s以內。
6.3 風機運行、維護及檢查
6.3.1 風機的運行參數如風量、風壓、電流、軸承振動、軸承溫度及風機進口和(或)出口的介質溫度等，應在控制室內有儀表顯示。對軸流式風機宜做到在線監視畫面上顯示風機運行工況點位于性能曲線上的位置，以便運行人員了解風機的實際運行情況，避免風機在不希望的工況下運行。大型風機的軸承振動和溫度還應設有報警信號。所有監視儀表都應定期進行校準。
6.3.2 定期對風機進行維護檢查，及時排除運行中出現的故障和異常。主要檢查項目有軸承、磨損和腐蝕程度、積灰情況、焊縫和鉚接質量、動葉調節軸流式風機的動葉螺栓連接、油系統和調節機構，
包括行程范圍、靈活性、各調節葉片動作的一致性，以及實際開度與指示儀表的一致性等。
6.3.3 風機正式投運前，各電廠應根據制造廠提供的資料和管網系統的具體條件，以及安裝完畢后的一系列調整試驗的結果，編制出具體可行的風機運行操作規程，作為運行人員操作、檢查、維護的依據。
