1、Designation: D 5954 98 (Reapproved 2006)Standard Test Method forMercury Sampling and Measurement in Natural Gas byAtomic Absorption Spectroscopy1This standard is issued under the fixed designation D 5954; the number immediately following the designation indicates the year oforiginal adoption or, in
2、the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test covers the determination of total mercury innatural gas at concentrations
3、 down to 1 ng/m3. It includesseparate procedures for both sampling and atomic absorptionspectrophotometric determination of mercury. The proceduredetects both inorganic and organic forms of mercury.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport
4、 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 prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1193
5、 Specification for Reagent Water3. Summary of Test Method3.1 Mercury in a gas stream is adsorbed onto gold-coatedsilica beads and subsequently directly desorbed by heat into along path-length quartz cell connected to an atomic absorptionspectrophotometer. Mercury atoms are detected by measuringtheir
6、 absorbance of light from a mercury source lamp at acharacteristic wavelength. The mercury concentration is ob-tained from the absorbance peak area by comparison tostandards prepared at the time of analysis.4. Significance and Use4.1 This test method can be used to measure the level ofmercury in nat
7、ural gas streams for purposes such as determin-ing compliance with regulations, studying the effect of variousabatement procedures on mercury emissions, checking thevalidity of direct instrumental measurements, and verifyingthat mercury concentrations are below those required fornatural gas processi
8、ng and operation.4.2 Adsorption of the mercury on gold-coated beads canremove interferences associated with the direct measurementof mercury in natural gas. It preconcentrates the mercurybefore analysis thereby offering measurement of ultra-lowaverage concentrations in a natural gas stream over a lo
9、ng spanof time. It avoids the cumbersome use of liquid spargers withon-site sampling, and eliminates contamination problems as-sociated with the use of potassium permanganate solutions.3,4,55. Apparatus5.1 Atomic Absorption Spectrophotometer, equipped with a10-cm-long path quartz absorption cell and
10、 a mercury sourcelamp (EDL or other high intensity lamp). It must be capable ofcollecting and integrating data over a 30- to 60-s time window.Background capabilities are strongly recommended.NOTE 1Detection sensitivity may vary significantly depending on thetype of spectrophotometer and its accessor
11、ies.5.2 Rotameter or Other Flow Measurement Device capableof attaining and regulating air at approximately 500 mL/min.5.3 Rotameter or Other Flow Measurement Device capableof attaining and regulating the natural gas sample at approxi-mately 1000 to 2500 mL/min.5.4 Dry or Wet Positive Displacement Te
12、st Meter, or othercalibrated total flow measurement device for measuring thevolume of the sample.5.5 TFE-Fluorocarbon Tubing, to make connections to theatomic absorption spectrophotometer. The size should beappropriate for the quartz absorption cell.5.6 Quartz Tubing, 12 cm long,14-in. outside diame
13、ter, tobe used for sorbent (gold-coated silica) packing.NOTE 2All glass and plastic ware coming into contact with thesample must be acid washed with 20 % nitric acid and thoroughly rinsedwith water.1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct res
14、ponsibility of Subcommittee D03.05 on Determination ofSpecial Constituents of Gaseous Fuels.Current edition approved Dec. 1, 2006. Published February 2007. Originallyapproved in 1996. Last previous edition approved 1998 as D 595498.2For referenced ASTM standards, visit the ASTM website, www.astm.org
15、, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Schroeder, W.H., “Sampling andAnalysis of Mercury and its Compounds in theAtmosphere,” Environmental Science mercury sampling; n
16、atural gasASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such r
17、ights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for addition
18、al standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the AS
19、TM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 5954 98 (2006)5
