Grobar 40 CFR The fewer components eliminates dew point problems, reactivity, is more accurate and can be blended at a higher pressure. Open the valve on the L cylinder, then open the valve on Cyhnder B, which w i l l result in the transfer of nearly all of the contents of Cyhnder B into the L cylinder. Either the average of the two consecutive checks, or the latest check agreeing within the repeatability limits of the previous check on each component may be used as the reference standard for all subsequent runs until there is a change in instrument operating conditions. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn.
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Keywords gas analysis; gas chromatography; natural gas composition ; Butane content; Carbon dioxide content--natural gas; Composition analysis--gases; Ethane content; Gas chromatography GC --gaseous fuels; Gaseous fuels; Helium content; Hexanes content; Hydrogen content--petroleum products; Isobutane; Isopentane; Methane content; Natural gas service systems; Nickel content--petroleum products; Oxygen content; Pentane content; Propane content; Rationale ASTM Headquarters is mandating a review of standards that use mercury and determine if its use is still appropriate, or if it should be removed, or replaced with a non-mercury alternative.
D includes a mercury manometer to monitor the pressure of the gas sample loop. Safer modern alternatives exist such as digital manometers and absolute pressure transducers. Section 5. Figure 1 has been replaced with a diagram containing a generic pressure indicator. References to pressure in mm Hg have been removed and replaced with the SI unit Pascal. The mercury changes were approved by main committee ballot in May, At that time it was discovered that section 1. Rather than publish a new revision which includes a known error, the committee agreed at the June meeting to halt publication until section 1.
A change to section 1. To remain compliant with ASTM standards, only two options exist: 1 Remove all inch-pound units throughout the method and replace with SI units where applicable 2 Provide inch-pound equivalents for all SI units throughout the method. Due to the relatively few cases where inch-pound units are used, this ballot revision seeks to remove all inch-pound units and replace them with SI units.
The changes necessary to remove mercury from the method that were approved but not published, are still present in this ballot for consideration.
ASTM D1945-03 PDF
This pressure need not be measured precisely, as the concentration of nitrogen in the mixture thus prepared must be determined by comparison to nitrogen in the reference standard. The well type inherendy offers better precision and is preferred when calibrating w i t h pure components. Obtain a corresponding response on the reference standard. Methane should be in a 1-L cyHnder at MPa atm pressure. A value of may be used for the molecular weight of the octanes and heavier reverse-flow peak. The percent nitrogen is multiplied by 0. Make calculations on ethane and heavier components in the same manner as for the complete analysis method.
Mikasar The width of the chart shall be not less than mm. The relationship is independent of temperature, sample size, and carrier gas flow rate. The separation should be completed within 40 min, including reversal of flow after n-pentane to yield a group response for hexanes and heavier components. NOTE 1 — T h e sample size limitation of 0. SuiBcient accuracy can be obtained for the determination of all but the minor constituents by the use of this sample size.