API机械密封冲洗方案.ppt

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1、1,API Piping PlansAPI 冲洗方案,November 2004,JC Tianjin TrainingModule 4.3,Seal Environment密封环境,API Piping Plans API 冲洗方案,Integral(internal)recirculationfrom pump discharge to seal,Advantage-No external piping Limitations-Changing flow rate required dismantling of pump-For clean pumpages only,API Piping

2、 Plans API 冲洗方案,Points to Note for API Plan 02:-The injection tapping is used for venting prior to startup.-API plan 02 is often used together with plan 62,especially on high temperature bellows seals.,API Piping Plans API 冲洗方案,No flushing to the mechanical seal(dead-ended),Points to Note for API Pl

3、an 11:-Use an orifice to restrict the flow rate if the discharge pressure is 3 bar higher than seal chamber pressure.-Use on clean and low abrasives duties,API Piping Plans API 冲洗方案,Seal Flushing By-Pass from Discharge单密封通过出口进行冲洗,Recirculation from seal chamber through a flow control orifice and bac

4、k to pump suction,Points to Note for API Plan 13:-Use an orifice to restrict the flow rate if the seal chamber pressure is 3 bar higher than suction pressure.-handle abrasives duty better than API plan 11-higher seal chamber pressure to suppress vaporisation,API Piping Plans API 冲洗方案,+,=,Points to N

5、ote for API Plan 14:-Flow back to suction side will evacuate vapours that may collect in seal chamber.-Recommended for light hydrocarbon service.,API Piping Plans API 冲洗方案,Recirculation from pump discharge through a flow control orifice and cooler to sealOpen Loop Cooling Circuit,Cooling Water Outle

6、t,Cooling Water Inlet,API Piping Plans API 冲洗方案,Recirculation from a pumping ring in the seal chamber through cooler and back to sealClosed Loop Cooling Circuit,Throat bushing,Suction,Discharge,18-24,Vent at highest point of the piping,Cooling Water Outlet,Cooling Water Inlet,mechanical seal with pu

7、mping ring,Heat exchanger,API Piping Plans API 冲洗方案,Points to note for API Plan 23:Thermosyphon design*heat exchanger 18 to 24 above pump centre line.*Prevent overheating in standby and startup.Install close fitting neck bushing at the bottom of seal chamber to isolate the heat from the impeller end

8、.Used on high temperature applications to minimise heat load on the cooler by cooling only small amount of liquid that is recirculated.For high temperature boiler feed pump applications Other applications*high temperature liquid close to bubble point.,API Piping Plans API 冲洗方案,Recirculation from pum

9、p discharge through a cyclone separator delivering clean fluid to the sealand fluid with solids back to pump suction line,API Piping Plans API 冲洗方案,Points to Note for API Plan 32:-Chose a proper source of seal flush to eliminate the potential for vaporisation of the injected fluid and to avoid conta

10、mination of the fluid being pumped with the injected flush.-Install a labyrinth bushing at the bottom of the stuffing box to control the flushing and pressure if necessary.,API Piping Plans API 冲洗方案,Single Seal Flushing from External Source单密封通过外部来源进行冲洗,Throat Bushing,Recirculation from pump dischar

11、ge through a cyclone separator delivering clean fluid through a cooler and then to seal and fluid with solids back to pump suction line,Cooling Water Outlet,Cooling Water Inlet,API Piping Plans API 冲洗方案,Needle valve,External reservoir providing a dead-ended blanket of fluid to the quench connection

12、of the gland.,Points to Note for API Plan 51:-Dead ended blanket on atmospheric side of seal to prevent freezing of moisture.Seal face will not stick together when the pump started.Typical application:Pump operating below 0 C-API 610 8th Edition has eliminated this piping plan.,API Piping Plans API

13、冲洗方案,Piping Systems,API Piping Plans API 冲洗方案,A fluid used as a lubricant or buffer between dual mechanical seals.The buffer fluid is always at a pressure lower than the pump process pressure being sealed.,A fluid which is introduced between dual mechanical seals to completely isolate the pump proce

14、ss liquid from the environment.Pressure of the barrier fluid is always higher than the pump process pressure being sealed.,The purpose of fluid circulationis to remove heat from mechanical seal,API Piping Plans API 冲洗方案,On applications below ambient temperature,circulation of barrier fluid may not b

15、e desirable.The atmosphere will heat the reservoir and consequently add heat to the seal area.,Fluid circulation by temperature difference between the seal and reservoir.Higher temperature liquid at seal has lower density rises to the reservoir.Lower temperature liquid at reservoir has higher densit

16、y falls to the seal to provide cooling.,External Force Circulation,Thermosyphon,Pumping Ring,Dead Ended,API Piping Plans API 冲洗方案,Points to Note for API Plan 52:Typically used with an Arrangement 2 unpressurised dual seal.During normal operation,circulation is maintained by an internal pumping ring.

17、The reservoir is usually continuously vented to a vapour recovery system and is maintained at a pressure less than the pressure in the seal chamber.,Pressure Gauge,Level Gauge,Fill valve,Orifice,Drain,Level Switch(H),Level Switch(L),Pressure Switch,(Normally Open),Vent valve,External reservoir provi

18、ding buffer fluid for the outer seal of an unpressurised dual seal arrangement.,API Piping Plans API 冲洗方案,Pressure Gauge,Level Gauge,Level Switch(L),Vent Valve(Normally Close),Orifice,Pressure Switch,External Pressure Source,One-way Block Valve(Normally Open),Points to Note for API Plan 53:Typically

19、 used with an Arrangement 3 pressurised dual seal.During normal operation,circulation is maintained by an internal pumping ring.The reservoir pressure is greater than the process pressure being sealed.,External reservoir providing pressurised barrier fluid for the outer seal of an pressurised dual s

20、eal arrangement.,Drain,API Piping Plans API 冲洗方案,Points to Note for API Plan 54:Typically used with an Arrangement 3 pressurised dual seal.During normal operation,circulation is maintained by an external pump or pressure system.The circulating barrier fluid pressure is greater than the process press

21、ure being sealed.,External barrier fluid system providing pressurised barrier fluid for the outer seal of an pressurised dual seal arrangement,API Piping Plans API 冲洗方案,Safe to use,handle,storeStable liquid at ambient temperatures Not a VOC,VHAP or other regulated compoundNon flammableNon foaming wh

22、en pressurisedClean and good lubricityCompatible with process fluid Compatible with seal materialsGood heat transfer properties Good flow qualities at very low temperaturesLow solubility of gasLocal availabilityLow cost,VOC:Volatile Organic CompoundVHAP:Volatile Hazardous Air Polutants,Selection of

23、Buffer/Barrier Fluid,API Piping Plans API 冲洗方案,Tapped connections for the purchasers use,Point to Note for API Plan 61:Typically this plan is used when the purchaser is to provide fluid(such as steam,gas,or water)to an auxiliary sealing device.,API Piping Plans API 冲洗方案,Points to Note for API Plan 6

24、2:The quench may be required to prevent solids from accumulating on the atmospheric side of the seal.Typically used with a close-clearance throttle bushing.,API Piping Plans API 冲洗方案,Single Seal Quench from External Source单密封通过外部急冷,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 14(Plan

25、11+13)Plan 53s-Arrangement 3,Contacting Wet(CW)Seals53a traditional configuration53b bladder accumulator53c piston pot/accumulatorContainment SealPlan 72 Arrangement 2 w/Containment Seal(CS)Plan 75 Arrangement 2 w/Containment Seal(CS)Plan 76 Arrangement 2 w/Containment Seal(CS)Gas Barrier SealsPlan

26、74 Arrangement 3,Non-Contacting(NC)Seals,Plan 53a(A.4.12),Arrangement 3,Contacting Wet(CW)SealsDual Pressurised(Double)SealsUtilises direct nitrogen blanket for pressuredue to nitrogen entrainment in the barrier liquidAPI 682 limits the maximum nitrogen pressure to 10 barg,JC recommendation is maxim

27、um nitrogen pressure 21 barg,as long as the barrier fluid temperature is less than 120C,API 682 2nd Edition API 682 第二版 New Piping Plans 新的冲洗方案,Plan 53b(A.4.12),Arrangement 3,Contacting Wet(CW)SealsDual Pressurised(Double)SealsUtilizes bladder accumulator for pressureBladder eliminates nitrogen cont

28、act with barrier liquidAllows for higher pressure applications,Configuration Includes:AccumulatorPressure IndicatorPressure SwitchHeat Exchanger,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 53c(A.4.12),Arrangement 3,Contacting Wet(CW)SealsDual Pressurised(Double)SealsUtilizes piston p

29、ot for pressure,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 53c(A.4.12),Allows for higher pressure applications Configuration includes:Piston potPressure indicatorPressure switchHeat exchangerLevel switch,Piston pot eliminates nitrogen contact with barrier liquidPiston provides const

30、ant pressure ratio to seals(1.1:1),Spring,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Barrier Fluid Temperature(7.3.4.1.1)隔离流体温度,Liquid barrier systems shall be designed such that that maximum temperature differential between the barrier fluid inlet and outlet immediately adjacent to the

31、seal chamber is:8 degree C for glycol/water or diesel barrier fluids;and 16 degree C for mineral oil barrier fluid,Plan 11 with Plan 53,Arrangement 3 may use Plan 11&53Improved heat transferReverse pressure capability“Back to Back”seals uses Plan 53,API 682 2nd Edition API 682 第二版New Piping Plans 新的

32、冲洗方案,Plan 72(A.4.16),Arrangement 2,w/Containment Seal(CS)Dual Un-Pressurised(Tandem)SealsDry-running secondary containment sealLow pressure nitrogen sweep(purge)Sweeps primary leakage to collection systemDilutes primary leakage to lower emission levelsUsed in conjunction with Plan 75 or 76,CSV:conta

33、inment seal ventCSD:containment seal DrainGBI:gas buffer inletFIL:coalescing filter,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 74(A.4.17),Arrangement 3,Non-contacting Seals(NC)Dual Pressurised(Double)Gas Barrier SealsNitrogen gas barrier 1.75-2 bar(25-30 psi)above seal chamber press

34、ureZero emissionsEssentially a T2800 panel,GBI:gas buffer inlet GBO:gas buffer outlet(NC)(used only to depressurize),API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 75(A.4.18),Arrangement 2,w/Containment Seal(CS)Dual Un-Pressurised(Tandem)SealsDry-running secondaryCondensate collection r

35、eservoir(8.6.5.2)Used when primary seal leakage may condense(does not completely vaporize)May be used in conjunction with Plan 72,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 76(A.4.19),Arrangement 2,w/Containment Seal(CS)Dual Un-Pressurised Seals(Dry-running secondary)Primary leakage routed to flare or ventUsed when primary seal leakage will not condense(completely vaporizes)Essentially a 48SC or 28LD panel leakage detection May be used in conjunction with Plan 72,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,