ASTM E1675-2004(2012) Standard Practice for Sampling Two-Phase Geothermal Fluid for Purposes of Chemical Analysis《化学分析用两相地热流体取样的标准规范》.pdf

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1、Designation: E1675 04 (Reapproved 2012)Standard Practice forSampling Two-Phase Geothermal Fluid for Purposes ofChemical Analysis1This standard is issued under the fixed designation E1675; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis

2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The purpose of this practice is to obtain representativesamples of liquid and steam as they exist in

3、a pipelinetransporting two-phase geothermal fluids.1.1.1 The liquid and steam samples are collected andproperly preserved for subsequent chemical analysis in thefield or an off-site analytical laboratory.1.1.2 The chemical composition data generated from theanalysis of liquid and steam samples may b

4、e used for manyapplications important to geothermal energy exploration,development, and the long-term managed exploitation ofgeothermal resources. These applications include, but are notlimited to, resource evaluations such as determining reservoirtemperature and the origin of reservoir fluids, comp

5、atibility ofproduced fluids with production, power generation and rein-jection hardware exposed to the fluids (corrosivity and scaledeposition potential), long-term reservoir monitoring duringfield exploitation, and environmental impact evaluations in-cluding emissions testing.1.1.2.1 To fully utili

6、ze the chemical composition data in theapplications stated in 1.1.2, specific physical data related to thetwo-phase discharge, wellbore, and geothermal reservoir maybe required. Mathematical reconstruction of the fluid chemistry(liquid and steam) to reservoir conditions is a primary require-ment in

7、many applications.At a minimum, this requires preciseknowledge of the total fluid enthalpy and pressure or tempera-ture at the sample point. Fluid reconstruction and computationsto conditions different from the sample collection point arebeyond the scope of this practice.1.2 This practice is limited

8、 to the collection of samples fromtwo-phase flow streams at pressures greater than 70 kPa gauge(10 psig) and having a volumetric vapor fraction of at least20 %. This practice is not applicable to single-phase flowstreams such as pumped liquid discharges at pressures abovethe flash point or superheat

9、ed steam flows. Refer to Specifica-tion E947 for sampling single-phase geothermal fluids.1.3 The sampling of geothermal fluid two-phase flowstreams (liquid and steam) requires specialized samplingequipment and proper orientation of sample ports with respectto the two-phase flow line. This practice i

10、s applicable to wellsnot equipped with individual production separators.1.4 In many cases, these techniques are the only possibleway to obtain representative steam and liquid samples fromindividual producing geothermal wells. The sampling prob-lems that exist include the following:1.4.1 Unstable pro

11、duction flow rates that have a largedegree of surging,1.4.2 Unknown percentage of total flow that is flashed tosteam or is continuously flashing through the productionsystem,1.4.3 Mineral deposition during and after flashing of theproduced fluid in wellbores, production piping, and samplingtrains,1.

12、4.4 Stratification of flow inside the pipeline and unusualflow regimes at the sampling ports, and1.4.5 Insufficient flash fraction to obtain a steam sample.1.5 This practice covers the sample locations, specializedsampling equipment, and procedures needed to obtain repre-sentative liquid and steam s

13、amples for chemical analysis.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations

14、 prior to use. For specific hazardstatements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2E947 Specification for Sampling Single-Phase GeothermalLiquid or Steam for Purposes of Chemical Analysis2.2 Other Document:ASME Code Section VIII, Division 1(1986), Pressure VesselDesign, Fabricati

15、on and Certification31This practice is under the jurisdiction of ASTM Committee E44 on Solar,Geothermal and Other Alternative Energy Sources and is the direct responsibility ofSubcommittee E44.15 on Geothermal Field Development, Utilization and Materials.Current edition approved Dec. 1, 2012. Publis

16、hed December 2012. Originallyapproved in 1995. Last previous edition approved in 2004 as E1675 041. DOI:10.1520/E1675-04R12.2Annual Book of ASTM Standards, Vol 12.02.3Available fromAmerican Society of Mechanical Engineers 345 E. 47th St. NewYork, NY 10017.Copyright ASTM International, 100 Barr Harbo

17、r Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Summary of Practice3.1 Samples are collected from a pipeline carrying two-phase geothermal fluids by using a sampling separator thatseparates liquid and steam phases through centrifugal force. Afraction of the separated steam i

18、s condensed and a fraction ofthe separated liquid is cooled. Portions of the condensed steamand cooled liquid are collected in appropriate sample contain-ers for subsequent chemical analysis.4. Significance and Use4.1 The objective of this practice is to obtain representativesamples of the steam and

19、 liquid phases as they exist in thepipeline at the sample point, without allowing steam conden-sation or additional liquid flashing in the separator. A signifi-cant feature of the practice is the use of a cyclone-typeseparator for high-efficiency phase separation which is oper-ated at flow rates hig

20、h enough to prevent significant heat losswhile maintaining an internal pressure essentially the same asthe pipeline pressure.4.2 Another significant feature of the practice is to locate thesampling separator at a point on the pipeline where thetwo-phase flow is at least partially stratified to aid i

21、n theseparation process. It is neither necessary nor possible to passrepresentative proportions of each phase through the samplingseparator to obtain representative samples. The separator isusually attached to an appropriately oriented port to collecteach specific phasenormally on top of the line fo

22、r steam andat the bottom for liquid. In some cases, piping configurationscan generate unusual flow regimes where the reverse isrequired. If the ratio of one phase to another is not extreme,representative samples of each phase can often be obtainedfrom a horizontal port on the side of the pipeline.4.

23、3 This practice is used whenever liquid or steam samples,or both, must be collected from a two-phase discharge forchemical analysis. This typically includes initial well-testingoperations when a well is discharged to the atmosphere orroutine well production when a well discharges to a fluidgathering

24、 system and power plant. The combined two-phaseflow of several wells producing through a common gatheringsystem may also be sampled in accordance with this practice.4.4 This practice is not typically employed when individualwells produce to dedicated production separators. In thesecases, the separat

25、ed steam and liquid at the outlet of theproduction separator is sampled in accordance with single-phase sampling methods (Specification E947).5. Sample Location5.1 Sample locations vary and are dependent upon the grossquantities of each phase at the sample point. If sample ports areproperly oriented

26、 on the two-phase pipeline, a certain degree ofphase stratification will have occurred prior to sampling,facilitating further separation of the target phase through thesampling separator.5.2 Ports are ideally located on the top and bottom of thepipeline at least eight diameters downstream and two di

27、ametersupstream of major flow disturbances such as pipe bends,reductions, valving, etc. (see Fig. 1).5.2.1 In cases where the fluid contains substantial quantitiesof solid debris that may plug the sample port, the liquid portNOTE 1Minimum pipe diameters required upstream and downstream of major flow

28、 disturbances (piping bends, reductions).FIG. 1 Two-Phase Flowline Sampling Separator PortsE1675 04 (2012)2can be located at a 45 angle from the bottom, provided that asufficient liquid phase is present.5.2.2 If the flow regime is known, the number of ports maypossibly be reduced to a single port lo

29、cated either on the side,top, or bottom of the two-phase pipeline. Sufficient quantitiesof each phase must be available at the single port to allowcollection of representative steam and liquid samples.5.2.3 The sample ports must be at least 1-in. diameter andconfigured with a full-open port ball or

30、gate valve. Thisrequirement is necessary to ensure that only a minimal pressuredrop occurs through the port valve and associated piping. Scaleand debris often reduce the effective inner diameter of the port,therefore smaller ports are not recommended. The port sizerestriction also provides a safety

31、margin given the weight of theseparator and force needed to install and remove fittings fromthe port.5.3 Sample ports should never be located on side-streampiping from the main flow line unless only the side-streamfluids are to be characterized. The proportions of each phaseare not likely to remain

32、the same in a flow stream split off fromthe main flow line. Any pressure reduction in the side streampiping will change the steam and liquid compositions to anunknown degree.6. Equipment6.1 Sampling SeparatorA cyclone-type separator rated tothe pipeline pressure at the sample point, including a pres

33、suregage, temperature probe, and sight glass (optional). Theseparator should be designed to attach directly to the sampleport to minimize heat loss and pressure drop.6.1.1 A typical sampling separator is shown in Fig. 2. Thisis a cyclone-type separator with a 1-in. pipe inlet attached at atangent to

34、 the separator body. The separator is rated to 3 500kPa gauge at 260C (500 psig at 500F). A pressure gage andthermocouple are located at the top of the separator, and steamand liquid sample valves are located at the bottom. Steam isdrawn from the top of the separator through an axial pipeextending u

35、p from the bottom of the vessel. Liquid is drawndirectly off the bottom. Internal baffles prevent liquid filmsfrom rising up the inner walls of the vessel with the steam flowto the sample valves. Vortex breakers are placed in the bottomof the vessel to prevent steam entrainment in the liquid flow to

36、the sample valves.6.1.1.1 The vent valve on the side of the sampling separator(No. 2 in Fig. 2) can be used to maintain an excess flow ofsteam and liquid through the separator, beyond the amountneeded for sample collection. If sufficient quantities of eachphase are present, the side vent valve will

37、maintain a liquidlevel about 50 mm (2 in.) above the liquid sample valve (No.5inFig. 2). This allows collection of both steam and liquidsamples from the separator without the need to adjust the liquidlevel.6.1.1.2 An optional sight-glass (PFA-fluorocarbon) for liq-uid level is located along one side

38、 of the separator to aid inproper separator operation and confirm the position of theliquid level. The sight glass is only rated to 1 700 kPa gauge(250 psig) and must be removed for higher pressure operation.6.2 Sample HosesSample hoses are PFA-lined stainlesssteel braided hoses rated to 500 psig an

39、d 450F. JIC typefittings or quick-disconnect fittings attach hoses to the separa-tor and condenser. Hoses are dedicated to either steam or liquidservice to prevent cross-contamination. The inner diameter ofthe hose should not exceed 0.375 in. Stainless steel tubing mayalso be used (0.25 to 0.375-in.

40、 outside diameter), although it isless convenient. Convoluted, flexible stainless steel hose isspecifically excluded due to potential entrapment and contami-nation problems caused by the internal convolutions.6.3 CondenserAsample condenser configuration with twosets of stainless steel tubing coils i

41、s recommended. One set ofcoils is dedicated for condensing steam and the other isdedicated for cooling liquid. The steam condenser coil has apressure/vacuum gage located at the sample outlet and aregulating valve at the inlet. The steam flow can be precisely1) 1 in. Two-Phase Inlet (Hammer Union)2)1

42、2 in. Vent Valve (Regulating Valve or Ball Valve)3)14 in. Steam Sample Valve (Regulating Valve)4)12 in. Steam Bleed Valve (Regulating Valve)5)14 in. or38 in. Liquid Sample Valve (Ball Valve)6)38 in. Teflon Sight Glass (250 psi limit:116 in. wall, Teflon PFA)7)14 in. 12 in. Type K Thermocouple8) Pres

43、sure Gage with Surge Protector Valve9)12 in. Steam Outlet Pipe10) Baffle Ring11) Vortex Breaker Plates12) Separator Body, 4 in. I.D. 12 in.Material specification: All metal components 304 or 316 stainless steelFIG. 2 Sampling SeparatorE1675 04 (2012)3regulated at the inlet as opposed to regulating t

44、he flow ofcondensate and gas at the outlet that can result in large pressuresurges and the hold-up of gas or condensate phases in the coils.The liquid cooling coil has a regulating valve at the outlet andan optional pressure gage. Regulating the outlet flow preventsflashing of liquid at the inlet to

45、 the condenser where chemicaldeposition could occur. Dedicated condensers with single setsof tubing coils for sampling either steam or liquid also can beused (see Fig. 3 and Fig. 4).6.3.1 The condenser coil tubing must not exceed 0.25-in.outside diameter to prevent the segregation of gas and conden-

46、sate phases during sampling of steam. Larger tubing sizes alsoincrease the risk of contamination and chemical depositionduring liquid sampling due to low fluid velocities and longerresidence times within the tubing. In cases where the liquidcontains substantial quantities of particulate matter, 0.37

47、5-in.outside diameter tubing coils may be used to minimize coolingcoil plugging problems.6.3.2 In cases where the noncondensible gas concentrationin steam exceeds approximately 5 % by weight, the outlet ofthe steam condenser coil should be at an elevation below theinlet with a continuous down-slope

48、in the tubing from inlet tooutlet. This allows the small volume of condensate to freelydrain out of the condenser and prevents hold-up within thecoils.6.4 Condenser cooling can be achieved by an ice/water bathsurrounding the coils or by a continuous overflow of coolingwater running into the vessel h

49、olding the coils (configurationshown in Fig. 3 and Fig. 4). Alternate configurations mayinclude a water-tight jacket around the coils through which aconstant source of cooling water flows. A source of coolantmay be a glycol/water mixture circulated through the con-denser jacket and an external fan-cooled heat exchanger.6.5 Pressure GageFor the measurement of separator pres-sure. Bourdon-tube type gages or pressure transducers may beused.Apressure-snubbing device is recommended to minimizethe pressure spikes and surges common in two-phase flowlines. The full