英文版DLT50541996火力发电厂汽水管道设计技术规定

Professional Standard of the Popeples Republic of ChinaDL/T 5054-1996Technical Specification for the Steam/Water Piping Design of Fossil Fuel Power Plant火力发电厂汽水管道设计技术规定Notice on the issuing of power industry standard Electric Power Industry of People Republic of ChinaDian Ji 1996 No.340After inspection and approval, Technical Specification for the Steam/WaterPiping Design of Fossils Fuel Power Plant is approved to be a reference specification and is hereby issued. The standard code is: DL/T 5054-1996This standard shall be implemented from October 1, 1996.Please notify the Ministry of Electric Industry, Electric Power Planning and Design General Institution of the problems and suggestions during the specifications implementation, also a copy of it shall be sent to the office of ministry standardization leading group.This standard is under the charge of China Water Power Press to publish.Unit and meaning of the frequently used symbols:SymbolUnitMeaningPMPadesigned pressurePNMPanominative pressurePTMPatest pressurePdPa, MPadynamical pressure of the media inside the pipePd1Pa, MPadynamical pressure at the initial end of the pipePd2Pa, MPadynamical pressure of the pipe endPOPa, MPastagnation pressure at the initial end of the pipeP1Pa, MPapressure at the initial end of the pipeP2Pa, MPapressure of the pipe endPCPa, MPacritical pressure of the media inside the pipePdPa, MPacritical dynamical pressure of the media inside the pipe-ratio of the pressure at the initial end of the pipe and the pressure at the end of the spacec-ratio of the pressure at the initial end of the pipe and the critical pressuretdesign temperature or working temperatureterdesign installation temperatureb20MPaminimal tensile strength of the steel products at 20 3MPaminimal yield limit of the steel products at design temperaturet3 (0.2%)MPaminimal yield limit when the steel products residual deformation is 0.2% at design temperaturetDMPa100, 000 h average endurable strength of the steel materials at design temperatureTMPasafe allowable stress of the steel products at design temperature-safe allowable stress compensation factorDNmminside nominal diameterDOmmpipe external diameterDimminternal pipe sizesmmmminimal straight pipe wall thicknessSCmmcalculated wall thickness of the straight pipeSmmwall thickness of the straight pipeA-negative deviation coefficient of the pipe thicknessGt/hmedia mass flowGmaxt/hmedia maximal mass flowGmint/hmedia minimal mass flowQm3/hmedia volumetric flowvm3/kgmedia specific volumev0m3/kgpipeline initial end stagnation specific volumev1m3/kgmedia specific volumeat the pipe initialv2m3/kgmedia specific volume at the pipe terminalvm3/kgmedia critical specific volume-media specific volume ratio at the pipe terminal and initial end0-ratio of media critical specific volume and pipeline initial media specific volumekg/m3media density1kg/m3media density at the pipeline initial2kg/m3media density at the pipe terminalwm/smedia flow velocitymkg/(m2s)media mass velocityw0m/smedia critical velocitym0kg/(m2s)media critical mass flow velocityLmoverall pipeline stretched length-pipeline friction coefficientR-Reynolds number-resistance coefficient of pipeline+ 1-pipelines general coefficient of local resistancee-pipe equivalent roughnessgm/s2acceleration of gravityk-steam adiabatic exponenta-media mass flow velocity ratio before and after the local changes of the pipelineH1mheight mark of the pipe initial endH2mheight mark of the pipe terminal endPatPaatmospheric PressurePopNworking load of the springPNinstallation load of the springPmaxNmaximal allowable load of the springmaxmmmaximal allowable distortion of the springHopmmspring working heightHetmmspring fitting heightH0mmspring free heightZtmmthermal walking value of the pipes supports and hangers along the vertical directionKmm/Nspring coefficient-friction coefficientLmaxmmaximal allowable spacing of the supporter and hangerIcm4pipe section moment of inertiaqkN/mself weight of the pipeline per unit lengthE20kN/mm2elastic modulus of the steel products at 20EtkN/mm2elastic modulus of the steel products under design temperaturet10-6/linear expansibility of steel products at working temperatureMPashear StressHfmmweld heighthummeffective throat thicknessXmmaxial displacement absorbed by the expansion jointYmmtransversal displacement absorbed by the expansion jointX0mmmaximal compensation quantity of the hose balance by the expansion jointY0mmmaximal compensation quantity of the transverse balance by the expansion joint1. General Provisions1.0.1 The purpose of this specification is to direct the design of the water/steam pipeline of fossil fuel power plant to ensure a secure, full-load, and economical operation.1.0.2 This specification is suitable for the steam/water piping design in the fossil fuel power plant with the unit main steam parameter as 27MPa, 550 (high temperature and reheated steam can be as high as 565) or below.The steam/water piping design within the generating units and the furnace shall not only comply with this specification, but also needs to be determined after being negotiated with the manufacturer.The heating network pipe and the pipe for transferring oil and air inside the power plant can refer to this specification.This specification is not suitable for the designs of fuel pipeline, fuel gas pipeline, hydrogen gas pipeline and underground straight buried pipe.1.0.3 Related standards quoted by this specification:Nominal diameter of the pipeline parts (3131047)Nominal pressure of the pipeline parts (3131048)Seamless steel pipe shall be used for high-pressure boiler (385310)For low- and media-pressure boiler, seamless steel pipe is used (GB3087)Carbon construction steel (313700)Spiral welded steel pipe (SY50365039)Low-pressure stream conveyance with welding steel pipe (3133092)Steel pressure vessel (GB150)Carbon steel covered electrode (GB5117)Low alloy structural steel (GB5118)Technical specifications on pipeline stress calculation of fossil fuel power plant (SDGJ6)Electric power construction and technical specification for the acceptance (pipeline section) (DJ56)Electric power construction and technical specification for the acceptance(Welding in fossil fuel power plant) (DL5007)Electric power construction and technical specification for the acceptance(Radio examination of the steel load-bearing pipeline butt-jointed seams) (SD143)Metallic technical supervision specification of the fossil fuel power plant (DLA38)Supervision code for boiler of power industry (SDl67)2 General policy conditions2.0.1 Design specificationsPiping design shall be carried out according to the thermodynamic system and setup. It requires good material sources, proper setup, good indemnification, smooth drainage, smaller flow resistance, low construction cost, appropriate hanger and support, convenient installation as well as maintenance, flexible extension, and shall be tidy and nice in appearance. Hydraulic impact and resonance shall be avoided, and noise shall be reduced.Piping design shall comply with related standards and specifications of the state and the ministry.2.0.2 Design parameter2.0.2.1 Design pressurePiping design pressure (gauge pressure) refers to the maximal working pressure of the interior media in service. For the utility of water pipe and design pressure, the influence of water columns static pressure shall be considered; when the pressure is lower than 3% of the nominal pressure, it will not be considered.The design pressure of the main pipe is applicable in the following specifications:(1) Main steam lineNominal working pressure at the boiler super-heater exit or working pressure at the maximum-continuous evaporative capacity of boiler shall be taken.When the boiler and steam turbine permits the pressure to be 5% greater (5% OP for short), 5% overpressure value shall be added.(2) Reheat steam pipelineThe pressure shall be 1.15 times of the pressure cylinder exhaust pressure under steam turbines maximal design capacity operating condition (see note). Pressure of the high temperature reheat pipe can be reduced to the undermost set-pressure of the safety valve at the re-heater outlet. Note: maximal design capacity operating condition of the steam turbine refers to the valve widely open condition (VWO for short) or valve widely open condition + 5% overpressure (VWO+5%OP for short) condition. (3) Steam turbines extraction lineNon-regulated extraction lines pressure shall be 1.1 times of the extraction pressure of the steam turbine at maximal design capacity condition, which shall be no lower than 0.1MPa:Regulated extraction line will use its maximum operating pressure.(4) Blow-down line of the backpressure steam turbineIts maximum operating pressure shall be adopted.(5) Steam pipe behind the relieverThe maximum operating pressure shall be adopted.(6) Steam water pipeline connected to the monopipe boiler starting vesselThe maximum possible operating pressure in all kinds of segregator operating conditions shall be adopted.(7) High pressure feed water pipelineFor non-variable speed feed water pump outlet pipe, from fore pump to main feed pump or from the main feed pump to boiler economizer entrance, pressures for each shall take the sum of the summit value of the performance curve with fore pump or main feed pump and the pumps water inlet side pressure respectively;As for variable speed feed water pump outlet pipe, from the feed pump outlet to the stop valve, the design pressure shall take the sum of the rated speed performance curve summit value and the water inlet side pressure; From stop valve at the pump outlet to entrance of the boiler economizer, the pressure shall take the sum of the pump water inlet side pressure and 1.1 times of pump popping pressure at the pumps rated speed and design flow. (8)Above high pressure feed water pipeline pressure shall consider the amendment on pressure made by water pump inlet temperature.For the constant-voltage deoxidizing system, the sum of the desecrator rated pressure and the water column static pressure at the maximum water level shall be adopted.For sliding pressure operation of deaerator, the sum of 1.1 times of the heated deaerator extraction pressure at steam turbines maximal design capacity condition and the water column static pressure at the deaerators maximal water level shall be taken. (9) Condensate pipeFor pipeline at the inlet side of the condensate pump, the water column static pressure (by this time, the pressure inside the condenser shall be taken as the air pressure) from the pump inlet center line to the turbine exhaust casings interface section and it shall be no lower than 0.35mpa;For the bypath at the outlet of the single stage pump and system pump, the pressure shall take the sum of the pump lift when the outlet valve is closed and the water inlet side pressure (the aforesaid water column static pressure); The pipeline at the condensate pumps outlet side of the two-stage pump system shall adopt the same pressure as that of the corresponding single stage pump system.The pipeline at the condensate booster pump outlet side of the two-stage pump system shall adopt the sum of the pump lifts of two pumps (condensate pump and condensate booster pump) when the outlet is shut down.(10) Heaters drainage pipeIt shall be 1.1 times of the extraction pressure under the steam turbines maximal design capacity operating condition and shall be no lower than 0.1MPa. When the drainage static pressure inside the pipeline triggers the pressure lifting and makes it larger than 3% of the extraction pressure, the influence of the static pressure shall be taken into account. (11) Boiler water blow-down pipelineBefore the boiler blow-down valve or when the pipeline after the blow-down valve is equipped with valve or closure plate that can elevate the pipe internal pressure, the design pressure for the periodic blow-down pipeline shall be no smaller than the sum of the undermost set-pressure of all the safety valves on the steam drum and the water column static pressure from the steam drums maximum water level to the pipe coupling points; as for the continuous blow-down pipeline, the design pressure shall be no lower than the undermost set-pressure of all the safety valves on the steam drum. If the pipe internal pressure will not go up after the boiler blow down valve, the design pressure of the blow-down line (periodic blow-down or continuous blow-down) shall be selected from Table 2.0.2-1.Table 2.0.2-1: The piping design pressure after the boiler blow-down valve MPa (g)Boiler pressure1.7504.150 4.1516.2006.20110.30010.301Piping design pressure1.7502.7504.1506.200(12) Feedwater recirculation lineWhen the unit system is taken, the last stop valve entering the deaerator and the previous pipeline shall take the design pressure of corresponding high pressure feed water pipe; for pipeline after the stop valve, the constant voltage deoxidizing system shall take the rated pressure of the deaerator; for the sliding pressure operation of deaerator, the design pressure shall be 1.1 times of the deaerators heat-up extraction pressure at the maximal design capacity operating condition of the steam turbine.When the piping-main scheme system is adopted, the restriction orifice and its previous pipeline shall adopt the design pressure of corresponding high pressure feed water pipe; for pipeline after the restriction orifice, when no valve is installed or valve on the media double outlets cannot be closed at the same time, the deaerators rated pressure shall be adopted.(13)Exhaust pipe after the safety valveIt shall be determined according to the hydraulic calculation result of the blow-down pipe.2.0.2.2 Design temperatureIt refers to the maximal working temperature of the media inside the pipe.The design temperature for the main pipe shall be selected according to the following specifications:(1) Main steam lineIt shall take the steams rated working temperature at the outlet of the boiler superheater plus the allowable temperature deviation during the boilers normal operation. Suggested temperature deviation is 5.(2) Reheat steam pipelineHigh temperature reheat pipe shall take the steam rated working temperature at the boiler reheater outlet plus the allowable temperature deviation during the boilers normal operation. Suggested temperature deviation is 5.Low-temperature reheat pipe shall adopt the high pressure cylinder steam exhaust parameter under the steam turbines maximal design capacity operating condition; get the isentropic corresponding temperature under the piping design pressure. If the manufacturer has special requirements, the design temperature shall take the maximal possible working temperature. (3) Steam turbines extraction lineNon-regulated extraction line take the extraction steam parameter under the steam turbines maximal design capacity operating condition and calculate the corresponding temperature by constant entropy under the design pressure of the pipeline;Regulated extraction line takes the maximal working temperature of the exhaust gas. (4) Blow-down line of the backpressure steam turbineSteam exhausts maximal working temperature shall be taken.(5) Steam pipe after temperature reducing deviceThe steams maximal working temperature at the temperature reducing device outlet shall be taken.(6) Aerated water pipeline connected to the monopipe boiler starting vesselThe maximal possible working temperature that the pipeline can have during all segregator operation conditions shall be taken.(7) High pressure feed water pipelineThe maximal working temperature of the high pressure feed water after using the high pressure heater.(8) Low voltage feed-water pipingFor the constant voltage deaerator system, the corresponding saturation temperature of the deaerators rated pressure shall be taken.As for the sliding pressure deaerator system, 1.1 times of the corresponding saturation temperature of the heated extraction pressure at the steam turbines maximal design capacity operating condition shall be taken. (9) Condensate pipeMaximal working temperature of the condensation water after the low pressure heater shall be taken.(10) Drainage pipe of the heaterThe corresponding saturation temperature according to the heater extraction lines design pressure shall be taken.(11) Boiler water blow-down pipePipeline before the boiler blow-down valve or after the blow-down valve installed with valve or closure plate, when the valve or closure plate can elevate the pipe internal pressure, the design temperature of the blow-down line (periodic blow-down or continuous blow-down) shall take the corresponding saturation temperature according to the undermost set-pressure for all steam drums safety valves.If the pipe internal pressure does not rise after the boiler blow-down valve, the design temperature of the blow-down line (periodic blow-down and continuous blow-down) can be selected from Table 2.0.2.2.Table 2: 2.0.2-2 Piping design temperature after the boiler blow-down valveBoiler pressure1.7504.150 4.1516.2006.20110.30010.301Piping design Temperature ()210230255280(12) Feed-water recirculation lineFor the constant voltage deoxidizing system, the corresponding saturation temperature at deaerators rated pressure shall be adopted; for the sliding pressure operation of deaerator, 1.1 times of the saturation temperature under deaerator heating extraction pressure at the steam turbines maximal design capacity operating condition shall be adopted.(13) Blow-down line of safety valveDesign temperature for the blow-down line shall be selected from the corresponding statistics according to the blow-down lines hydraulic calculation.2.0.2.3 Design installation temperatureDesign installation temperature can adopt 20.2.0.2.4 Nominal pressure and inside nominal diameter of the pipeThe rating of the pipeline parameter shall be expressed by nominal pressure, and the symbol is PIN. The pressure rating shall be in compliance with the regulations of national standard Nominal pressure of pipeline parts series (GB1048).Pipeline parameter rating can also be expressed by labeled pressure and temperature, like p5414 means its design temperature is 540 and its pressure is 14mpa.The pipelines inside nominal diameter shall be expressed by DN and the nominal diameter rating shall be in compliance with the regulations specified in national standard “Nominal diameter of pipeline parts“(GBl047).2.0.2.5 Conversion of the pipelines nominal pressureThe allowable working pressure and nominal pressure of the pipes and fittings can be converted as the equation below:PN (2.0.2-1)Where:p - The allowable working pressure, MPa; - The safe allowable stress of the steel products at design temperature, MPa. - .The corresponding reference stress of the nominal pressure; it refers to the media volumetric flow safe allowable stress of the steel products at certain temperature, MPa.Nominal pressures for the general home-made steel products are listed in APPX A.10A.15. 2.0.3 Water pressure testWater pressure tes