1、Recommended Practices for the Prevention of Water Damage to Steam Turbines Used for Electric Power GenerationFossil-Fueled PlantsAN AMERICAN NATIONAL STANDARDASME TDP-12006(Revision of ASME TDP-11998)Copyright ASME International Provided by IHS under license with ASME Not for ResaleNo reproduction o
2、r networking permitted without license from IHS-,-,-ASME TDP-12006(Revision of ASME TDP-11998)RecommendedPractices for thePrevention ofWater Damage toSteam Turbines Usedfor Electric PowerGenerationFossil-Fueled PlantsAN AMERICAN NATIONAL STANDARDThree Park Avenue New York, NY 10016Copyright ASME Int
3、ernational Provided by IHS under license with ASME Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-Date of Issuance: May 25, 2007The 2006 edition of this Standard is being issued with an automatic addenda subscription service.The use of addenda allows revisions mad
4、e in response to public review comments or committeeactions to be published as necessary. This Standard will be revised when the Society approves theissuance of a new edition.ASME issues written replies to inquiries concerning interpretations of technical aspects of thisStandard. The interpretations
5、 will be included with the above addenda service.ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American NationalStandards. The Standards Committee that approved the code or
6、standard was balanced to assure that individuals fromcompetent and concerned interests have had an opportunity to participate. The proposed code or standard was madeavailable for public review and comment that provides an opportunity for additional public input from industry, academia,regulatory age
7、ncies, and the public-at-large.ASME does not “approve,” “rate,” or “endorse” any item, construction, proprietary device, or activity.ASME does not take any position with respect to the validity of any patent rights asserted in connection with anyitems mentioned in this document, and does not underta
8、ke to insure anyone utilizing a standard against liability forinfringement of any applicable letters patent, nor assumes any such liability. Users of a code or standard are expresslyadvised that determination of the validity of any such patent rights, and the risk of infringement of such rights, ise
9、ntirely their own responsibility.Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted asgovernment or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accord
10、ance with the establishedASME procedures and policies, which precludes the issuance of interpretations by individuals.No part of this document may be reproduced in any form,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Me
11、chanical EngineersThree Park Avenue, New York, NY 10016-5990Copyright 2007 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.Copyright ASME International Provided by IHS under license with ASME Not for ResaleNo reproduction or networking permitted without license from
12、 IHS-,-,-CONTENTSForeword ivCommittee Roster . v1 Scope 12 Criteria . 13 Design Recommendations . 44 Operating Recommendations. 275 Testing, Inspection, Maintenance, and Monitoring. 296 Conclusion 30Figures1 Typical Flash Tank/Separators Arrangement: Local Control System 62 Typical Flash Tank/Separa
13、tors Arrangement: Integrated Control System . 73 Typical Leveling System Arrangement: Integrated Control System . 84 Typical Attemperator System . 95 Typical Drain System With Redundant Level Elements 116 Typical Heater Steam Side Isolation System: Local Control System 147 Typical Heater Steam Side
14、Isolation System: Integrated Control System . 158 Typical Heater Tube Side Isolation System: Local Control System . 169 Typical Heater Tube Side Isolation System: Integrated Control System . 1710 Typical Deaerator Arrangement With Drain System: Local Control System . 2011 Typical Deaerator Arrangeme
15、nt With Drain System: Integrated Control System 2112 Typical Deaerator Arrangement With Inlet Isolation: Local Control System 2213 Typical Deaerator Arrangement With Inlet Isolation: Integrated Control System 2314 Main Turbine: Typical Steam Seal Arrangement . 27Tables1 Symbol Legend 52 Device Ident
16、ification Letters . 6iiiCopyright ASME International Provided by IHS under license with ASME Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-FOREWORDIn the late 1960s, a substantial increase in the number of reported occurrences of steam turbinedamage by water indu
17、ction precipitated design recommendations from the two major U.S. steamturbine manufacturers in an attempt to reduce such incidents. Consequently, utilities and designersbegan formulating their own design criteria because of the economic need to keep the generatingunits in service. Realizing the com
18、mon need for a uniform set of design criteria to alleviate thisproblem, an American Society of Mechanical Engineers (ASME) Standards Committee was formed,consisting of representatives of utilities, equipment manufacturers, and design consultants todevelop recommended practices for use in the electri
19、c generating industry.This Standard, resulting from the work and deliberation of the Turbine Water Damage Preven-tion Committee, was approved as a Standard of the American Society of Mechanical Engineersby the ASME Standardization Committee and the ASME Policy Board, Codes and Standards, onJuly 26,
20、1972.In 1979, the Committee proposed a revision to this ASME Standard to include information oncondenser steam and water dumps, direct contact feedwater heaters, and steam generators. Thisproposed revision was approved by the ASME Standardization Committee on April 25, 1980.The 1985 revision was app
21、roved as an American National Standard on September 13, 1985. In1994, the ASME Board on Standardization approved the disbandment of the Committee onTurbine Water Damage Prevention along with the withdrawal of the standard TDP-1. This wasdue to perceived lack of interest and use by the industry.Subse
22、quent interest from users and potential users for TDP-1 convinced ASME to reconstitutethe Committee under the Board on Pressure Technology Codes and Standards in June 1997. Asa result of this committees work, TDP-1-1985 was revised and approved as an American NationalStandard on June 17, 1998.The cu
23、rrent Standard is a revision of TDP-1-1998. This Standard has been reorganized toincorporate combined cycle, multiple steam generators, cycling, and cogeneration technologyand to incorporate the capabilities of modern plant instrumentation and control systems. ThisStandard is not intended to impose
24、new requirements retroactively for existing facilities. Thisrevision was approved as an American National Standard on November 6, 2006.ivCopyright ASME International Provided by IHS under license with ASME Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ASME TWDP C
25、OMMITTEETurbine Water Damage Prevention(The following is the roster of the Committee at the time of approval of this Standard.)STANDARDS COMMITTEE OFFICERSR. G. Narula, ChairL. A. Kielasa, Vice ChairO. Martinez, SecretarySTANDARDS COMMITTEE PERSONNELG. A. Anderson, Sargent however, it is8recognized
26、that under some conditions it cannot beavoided. When this type of attemperator is required inthe motive steam line to control the temperature of thesteam entering a steam turbine, the following featuresshould be provided in addition to the other featuresrecommended in paras. 3.2.5 through 3.2.14:(a)
27、 The attemperators should not be allowed to oper-ate when the steam exiting the attemperator will containless than 50F (28C) of superheat unless a higher tem-perature is required by the turbine manufacturer.(b) The attemperator should be located as far fromthe steam turbine inlet as possible, but in
28、 no case closerthan 50 pipe diameters.(c) The attemperator should be located such that anyassociated water accumulation will drain in the directionof steam flow to a drain pot located at an elevationlower than the connection to the steam turbine. Thus,the piping should be sloped toward the drain pot
29、, andthe drain pot should be located between the attempera-tor and the steam turbine. This will result in the inten-tional creation of a low point to allow steam separationCopyright ASME International Provided by IHS under license with ASME Not for ResaleNo reproduction or networking permitted witho
30、ut license from IHS-,-,-ASME TDP-12006Fig. 4 Typical Attemperator SystemFTSteam pipeBlockvalveSpraycontrolvalveTell-talevalveAttemperatorFlow elementFIFrom attemperatorwater sourceFor details ofcontrolling functionsrefer to para. 3.2and water collection in the bottom of the pipe. An over-sized drain
31、 pot should be considered to enhance watercollection at high steam velocity.(d) The design of this type of attemperator systemshould be coordinated with the steam turbine manufac-turer.3.2.4 The use of reheat attemperators should pro-hibit activation or increase in spray when the steamconditions dow
32、nstream of the attemperator are within25F (14C) of saturation temperature.3.2.5 A power-operated block valve should beinstalled upstream of the attemperator spray controlvalve. This valve provides tight shutoff to prevent waterleaking past the spray control valve and provides abackup in the event th
33、at the spray control valve fails toclose when required (see Fig. 4). The spray control andblock valves constitute a double line of defense againstthe inadvertent introduction of spray water into thesteam lines. Since spray control valves are susceptibleto leakage, additional protection can be obtain
34、ed by useof a second block valve.3.2.6 The control system should automaticallyclose and override all manual and automatic settings of9the spray control and block valves when the master fueltrip actuates or the gas turbine trips.3.2.7 The control valve should be kept in the closedposition until the b
35、lock valve has reached the full openposition. This will prevent wire drawing of the blockvalve seat and subsequent leakage through the blockvalve.3.2.8 The block valve should be automaticallyclosed below a predetermined minimum load and anytime the demand signal to the control valves does not callfo
36、r spray. Sprays should not be released for automaticcontrol at loads where it can be determined that it isrelatively ineffective in reducing final steam tempera-ture. The loads used should be in accordance with theboiler/bypass valve manufacturers recommendations.Manual control should not prevent op
37、eration of the auto-matic protection features specified in para. 3.2.6.3.2.9 The attemperator should be designed toachieve suitable atomization at the lowest and higheststeam flow rates expected. Operation of the attempera-tor outside the range of suitable atomization isprohibited.Copyright ASME Int
38、ernational Provided by IHS under license with ASME Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-ASME TDP-120063.2.10 The control system for opening the spraycontrol valve should be designed to prevent the suddeninjection of large quantities of water.3.2.11 A man
39、ually operated drain valve shouldbe installed between the power-operated block valveand the spray control valve. This connection can be usedas a telltale for periodically testing for block valveleakage.3.2.12 If a bypass valve around spray controlvalves is used, it should be power operated and actua
40、tedto close when the block valve is closed. Use of manualbypass valves around spray control valves is not recom-mended. If a manual bypass is used, a second power-operated block valve should be provided as a secondline of defense. If a manual bypass is used, the inherentpossibilities of water induct
41、ion should be reducedthrough administrative control.3.2.13 A bypass of the block valve should not beprovided under any circumstances.3.2.14 Instrumentation should be supplied asshown in Fig. 4 to indicate the flow rate of the spraywater going to the attemperator.3.3 Motive Steam SystemsThe recommend
42、ations presented in the followingparas. 3.3.1 through 3.3.10 are intended to prevent theaccumulation of water in the motive steam piping sys-tems. Motive steam piping systems are defined in para.2.2. Motive steam systems include systems traditionallyreferred to as Main Steam, Hot Reheat Steam, ColdR
43、eheat Steam, and Boiler Feed Pump Turbine SteamSupplies for conventional steam cycles. Also includedare systems referred to as High Pressure, IntermediatePressure, Reheat, and Low Pressure Steam for combinedcycle units. Generally, a motive steam system can bethought of as any steam line normally car
44、rying steamto or from a steam turbine that is not an extraction lineas covered in paras. 3.5 and 3.6. Steam seal lines are notconsidered to be motive steam lines and are covered inpara. 3.9.3.3.1 Because of the lack of detection instrumenta-tion that will close steam turbine stop valves in timeto pr
45、event damage during steam turbine operation, noisolation recommendations are provided for the preven-tion of damage by water passing through the motivesteam piping and into the steam turbine. If such devicesare developed and marketed, consideration should begiven to including this instrumentation. R
46、apid closureof steam turbine valves should not be considered as amethod of preventing water induction into the steamturbine from a motive steam line.3.3.2 Normal closure of the steam turbine admis-sion stop and control valves with the opening of appro-priate drains is considered a suitable method fo
47、r10isolating the steam turbine during start-up and othertimes when condensate might be present and the valvesare already closed.3.3.3 A drain should be installed at each low pointin motive steam piping. The review for low pointsshould consider all portions of the lines from the steamsource outlet to
48、 the connection on the steam turbine,including any branches or dead legs (including thosecaused by valve closure). Each drain should consist ofa drain line connection or a drain pot connected directlyto the bottom of the motive steam line. As a minimum,drain pots should be used for the following lin
49、es (otherlines do not require drain pots, but this Standard doesnot prohibit their use):(a) motive steam lines that are prone to water accu-mulation during operation for which large drain collec-tion areas and/or water detection devices are desired.(b) cold reheat line at first low point downstream ofthe steam turbine exhaust (this application requiresredundant level elements; s
