1、BRITISH STANDARD Guide for procurement of power station equipment - Part 6-2: Wrbine auxiliaries - Feedwater heaters The European Standard EN 4551W2:1998 has the status of a British Standard ICs 27.040; 27.100 BS EN 155 10-6-2: 1998 NO COPYLNG WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT
2、LAW BS EN 46610-6-2:1998 National foreword This British Standard is the English language vemion of EN 4551-6-2:19!38. The UK participation in its preparation was entrusted to Technical Committee E/-/20, Power engineering steering committee, which has the responsibility to: - aid enquirem to understa
3、nd the text; - present to the responsible European commiee any enquiries on the interpretation, or proposais for change, and keep the UK interests informed, - monitor reW intemationai and European developments and promulgate themintheuK. A list of organizaons represented on this committee can be obt
4、ained on request to its secrem. Cross-references The British Standards which implement internationai or European publications referred to in this document may be found in the BSI Standards catalogue under the section entitled “Inonai Standards Correspondence Index“, or by using the “Find“ facility o
5、f the BSI Standards Electronic Catalogue. A British Standard does not purport to include ai the necessary provisions of a con- Usem of British Standards are responsible for their correct application Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary
6、 of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 17 and a back cover. This British Standard, hawig been prepared under the direction of the Engineering Sedor Board, was pubiished under the authority of the Standards Board and comes into effect on
7、15 May 1998 O BSI 1998 Amendments issued since publication Amd.No. Date I Textaffected ISBN O 680 29219 3 STD-BSI BS EN 455LO-b-Z-ENGL 1978 = Lb24bb7 Db77805 899 EUROPEXN STANDARD EN 4551WZ NORME EUROPENNI3 EUROP- NORM January 1998 ICs 27.040; 27.100 Descriptors: Electric power stations, turbines, w
8、ater heaters, purchase, user supplier relations, invitation of tenders, specifications, technical writing English version Guide for procurement of power station equipment - Part - horizontal in the condenser exhaust neck; - vertical water box up; - verticai water box down; - feedwater heaters with c
9、ondensing zone only, - two zone feedwater heaters (condensing and drain cooling or condensing and desuperheating zone); - three zone feedwater heaters (desuperheathg, condensing and dmin cooling zones); - header type feedwater heaters; - tube sheet type feedwater heaters; - separate drain coolers; -
10、 separate desuperheaters. - duplex LE heateis, This Guide does not cover feedwater heating systems using waste heat taken hm the exhaust of gas turbines or from the exhaust of a boder or gland steam; genem7 it oniy appies to systems which use extradion steam l equipment covered by this Gui4i.e is de
11、f2ned by its functh mW than design tgpe. -fora, the guidam to the speciftcatton is stated in peru% terms mther than being fi by a - pred.iced performance is achh - ancillay/ equipment .is pmpery siz - reliability, availability and safety requirements am ach- process and the quality ?wasum to be appl
12、ied, mis Guide does not - any allocacion of ?wpomhi * it* which are determined by the conEract. mis Guide does not prescmbe the amngement of the documents in the enquiry. NOTE As a compnehensive Eumpean envimnmental policy is still under prepamtion, this Guide does not adclress th8 envimnmatal impli
13、cations of the equipment. 2 Nonnatule qfiemnees This Guide for procurement incm by dated or undated ref-, pravis2ons fmn OW publicat.ionS. These nomnative references are cited in the appropriate places in the text and th publications are listed h.mqj%x For dated references, subsequent amendments to
14、or revisions of any of these publications apply to this Guide only when innporated in it by amendment or ?-eti - the tube surface within the tube sheet; - the flooded surface; - the inactive surface. 3.2.7 effective surface the effective surface is that portion of the total surface considered for th
15、e calculation of the exchanged heat. It does not include the tube surface within the tube sheet, the surface which is flooded andor the surface not exposed to steam or condensate on the shell side 3.2.8 support structure assembly of support plates or grids, internal walls and baffles, supporting the
16、 tubes and forming the internal drain coolhg and desuperheating zones 3.2.9 sole plates plates supporting the feedwater heater feet or saddles 3.2.10 entering drains and vents any iiquid or steam which enters int the heater from higher pressure stages or sources and combines with the shell side cond
17、ensate 3.2.11 terminal temperature difference (ITD) Merence between saturation temperature of the steam entering the heater and the outlet temperature of the water to be heated 3.2.12 approach Merence between the shell side outlet temperature of the condensate from the drain cooler and the tube side
18、 feedwater inlet temperature 3.2.13 tube side velocity water velocity through the tubes at average temperature (arithmetic average of the inlet and outlet temperature) O BSI 1998 STD.BSI BS EN 95510-b-Z-ENGL 1778 1b24bb7 Ob778LO L5h Page 6 EN 4661-6-21998 3.3 General terms 3.3.1 equipment plant, rnm
19、 system ador associated service to bepmvided in msponse to the enquiry 3.3.2 corzformit# fulfilment of specified requirem.ents by a product, p?vcess or service 3.3.3 pet$ormance obligations by spdf tests 3.3.4 opemting period tim between phnd outages or maintenunce periods during which the equipment
20、 is in operation ador does not restrict operational requirements of the power station 3.3.6 life expectarscy tim period over which the equipment might be vted to opmte with planned maintenunce but without replacement of a significant component 3.3.6 des life operating hours of the equipment on which
21、 esign calculations are bed 3.3.7 acceptabilitg comPl.iance with criteria defined by the purchaser for assessing the suitaMi - geological e.g. seismic ditions and character.stics of subs - geographic e.g. eevation, iqfluence of local topography and slw.cture.s; - hydrological e.g. jloodng and tides.
22、 4.3 Equipment task The specification should describe in geneml temzs the function, task or role of the equipment to e purchased, e.g. whether it is pad of a new power genemting plant, a modification to an twisting power generating plant, or mpmment equipment. Where appmprute) the specwcation should
23、 define the finetion and the hum limitations, if any, in the equipment connected to that which is beng supplied so that the equipment may avoid imposing adverse ditions or the supplier may suggest moditions to conmted quiprnent which w - the material of tubes. The specification may these should be t
24、o a recognized European or international standard. The specification should define the type and capacity of other services for the operation of the equipment such as compressed air or auxiiiary steam. 4.7 Other interfaces The specfieation should define th intmjces with existing ancary or new ancilia
25、ry equipment to be supplied under sepamte contracts which interact directly wiUL the equipment. Feedwater heaters may interact With: each other, civil works, the deaerator, the condenser, the extraction steam system, the feedwater system and the conlxol system of the power station. If these elements
26、, as well as insukition and erection, are supplied under separate contracts, then provisions should be taken by the purchaser in order to ensure technical cooperation and data exchanges between different suppliers. 4.8 Project programme The specification should describe the ovemtll programme and tim
27、escale in which the project is to be carried out. This muy include the principal da - aiualiary thermal insuiation and insulation equipment supports, inside temporary protection before and after installation, with provision of auxiliary nozzles (i needed), bottom or sole plates including anchor bolt
28、s; - instnunentation: level contsol system (including - accessories: - spare parts: - site activities: -tests: emergency trip system); level, pressure, temperature local indicators; hanjng and maintenance systems, etc.; gaskets, tube plugs, ozifices, etc.; transport, storage, erection, and cleaning;
29、 commissioning and performance tests; - documentation: equipment details, operation and maintenance manuais. O BSI 1998 STD-BSI BS EN q55LO-b-2-ENGL 1778 lb2Libb7 Ob77812 T27 Page 8 EN 466106-21998 Thepurchaser should - connecting points to the instnunents (with a list of these points); - the insula
30、tion supports (the type of the insuMion should be specified); - langes to the safety valves; - position and type of the suppork. The specmation should also supplies o?- coolng systems; - reSe-riCt2ons ag. pro ces d.isposal. 7.2 Manning levels The specmation should - operation of the plant at load le
31、vels, tempemhres, pressures and fluid velocities within the iimits taken into account by the supplier in the design; - variation of the above mentioned parameters due to the normal power changes (transients) of the Piant. 7.4 Operating hours The specification should define the total lve time require
32、d of the power station and the equipment (e-g. hours) and the required operating period of the equipment. 7.6 Start-up and shut-down The specification should indicate the total number and type of start-updshutdowns required of the equipment. The specification should distinguish between normal and em
33、ergency start-ups/shutdowns. The specifacation should - operation with one or more feedwater heaters out of service (if not specified as a design condition); - incorrect conditioning of the condensate; - operation with one string of feedwater heaters out of service at loads higher than the desigq -
34、overpressure of the feedwater heater; - incorrect operation of the level regulation system; - incorrect operation of the feedwater by-pass system; - incorrect operation of the drain system. 7.7 Further operational requirements 7.7.1 Load changes The purchaser should define the estimated time or freq
35、uency of the operational modes. An example: - operation at valve wide open (VWO) 5 % - operation at 75 % to 100 % load 65 % - operation at 50 % to 75 % load 20 % - operation from minimum continuous load up to 50 % 10 % - start-ups and shutdowns . 45 per year Page 9 EN 45510-6-21998 The important tra
36、nsients should be defined by their load ramps and frequencies. If the purchaser requires fatigue calculations then the supplier should identify all the data necessary to carry out the calculations. 7.7.2 Definition of operational modes Every operational mode is defined by: - mass flow of fluids (at
37、inlets and outlets); - temperature and enthalpy of fluidq - pressure in the water box and in the shell; - frequency and gradients of thermal cycles. 8 Life expectancI/ 8.1 Design life 8.1.1 General This should be a specific period which tulces into account the anticipated operating regime and recom-
38、d maintenance and wL broady equate to the stated opemting hours (see 7.4). The specification should define the design life of components which may be subject to periodic replucmt. The supplier should define limitations on equipment life, if any, and these should be included in the tender evaimtion p
39、rocess. 8.1.2 Number of start-up and shut-down cycles The specification should include an estimate of the nurnber of cpAe.s to which the equipment WU be subjected. 8.1.3 Equipment for monitoring remaining life The specification may request propos - approach - tube side pressure drop; - shell side pr
40、essure drop. This may also apply to other than design conditions. These should be dened in the enquiry document. 9.2 Petformance The specwcation may - list of extemal loads corresponding to ail opdonai modes (these loads may be given in a simplified way); these should include the steady state, trans
41、ient or cyclic loads imposed by external pipework on vessel branch connectionq - loads due to ambient and local conditions (snow, wind, earthwe, climate, etc.). The design should take into account methods, procedures and practices imposed by the specification only in the sense that these methods and
42、 procedures may be considered as minimum requirements (i.e. mechanid calculation codes, criteria for combinaiion of load. 10.1.2 Erosion and corrosion should erosion and/or corrosion problems be foreseen, the specification should specify minimum extra thickness or the use of corrosion resistant matm
43、ais to be taken into account in the design. The design shouid take into account the water quality and the type of chemical tseatment. 10.1.3 Fabrication procedures - Tolerances The specincation should state the dimensions and positions of nozzles and supports, attachment for ladders and platforms, a
44、nd insuMion supports. Required imensional tolerances, in order to ensure connection with other components of the system, should also be stated. The purchaser may request that, aRer receipt of the order, the supplier submit procedures and specifications for main construction operations such as: - cut
45、ting of pistes; - machining and drilling of tube sheet and support P*, - fabrication of headers, bending of tubes; - welding procedures specications. O BSI 1998 STD-BSI BS EN q55LO-b-2-ENGL 1778 lb24bb9 Ob97815 738 9 10.1.4 Specific design features The purchaser, based on experience of similar equip
46、ment, may forbid some types of conceptual and/or detail design. In doing so the specification should avoid unddy restricting competition. 10.1.6 Dimensional limitations If the equipment is to be instdied in a imited space or access is imited, the specification may specify maximum dimensions of compo
47、nents and equipment. 10.1.6 Protection against ingress of watedsteam to turbines Where the system supply or system design contract is separate from the feedwater heater equipment supply contract, provision should be made in each contract for cooperation between the system designer and equipment supp
48、lier in developing a system to automatically protect the turbine against the accidental reflux of water or steamhivater through the bled steam hes and potentiaiiy damagjng ingress int the turbine. 10.1.7 Maintenance features The specification should state requirements for man access provisions in th
49、e water header to allow access to the feed side of the tubeplate for inspection and tube plugging if needed. The tenderer may offer altemative features, but these should be justined by additional information or references. 10.1.0 Measuring and sampling points The specification may define where measuring and sampling points for tests during the lgetime of the equipment should be provided. The specifieation should indicate the type of performance tests (see chuse 17) and routine tests to be carried out, but the suppl
