ASTM D, D, and EPA 3C are used for the analysis of permanent gases (also called fixed gases) and light hydrocarbons at the percentage level in all. (A) Hydrocarbon compounds containing between one and five atoms of carbon plus benzene using ASTM D–03 (Reapproved ) (incorporated by. American Standards Testing & Materials (ASTM). D Standard D 03 Standard Test Method for Analysis of Natural Gas by Gas. Chromatography.
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Enter a 1- to 5-mL sample into the column and reverse the carrier gas flow after n-pentane is separated. The detector temperature shall be equal to or greater than the maximum column temperature. A value of may be used for the molecular weight of the octanes and heavier reverse-flow peak. This trouble has been experienced with some inlet systems even when clean and with the specified sample loop size.
The U-tube type is useful, since i t permits filling the sample loop w i t h up to two atmospheres of sample pressure, thus extending the range of all components. D195-03 sample-entry system must be vacuum tight.
40 CFR 600.011 – Incorporation by reference.
Larger samples may be used to determine low-quantity components to increase measurement accuracy. Connect Cylinder B to the L cylinder with as short a clean, small-diameter connector as possible.
Then fill Cylinder B with helium and hydrogen respectively to the pressures required to provide the desired concentrations of these components in the final blend. Also, the richer the gas, the worse the problem. For instance, propane asmt be the reference component for the butanes and pentanes i f propane is separated on the same column in the same sequence as the butanes and pentanes. Keep the system short and the drier small to minimize the purging required.
40 CFR – Incorporation by reference. | US Law | LII / Legal Information Institute
The concentration of a component in the reference standard gas should not be less than one half nor more than twice the concentration of the corresponding component in the test gas. Chromatographs are not truly linear over wide concentration ranges and linearity should be established over the range of interest. Evacuate the sample-entry system and observe the manometer for leaks. The fewer components eliminates dew point problems, reactivity, is more accurate and can be blended at a higher pressure.
Obtain a response on dry air for nitrogen and oxygen, i f desired. Obtain a corresponding chromatogram on the reference standard, which can be accomplished in about 5-min run time, as there is no need to reverse the flow on the reference standard. asrm
I asym the dew point is unknown, heat above the sampling temperature. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTfJI International Headquarters. It is permissible to use a response factor for oxygen that is relative to a stable constituent. This procedure also removes carbon dioxide, and the results obtained will be on the acid-gas free basis. To make this determination, enter a 5-mL sample into the short column and reverse the carrier gas after the separation of n-heptane.
Mount as required to dry the sample. Copper, brass, and other copper-bearing alloys are unacceptable. An accumulation of oily film in the sampling system greatly aggravates this problem. Methane and lighter may be expressed as the difference between and the sum of the determined components. This flow should quickly r e m m to the same flow rate and the baseline level out. The operating conditions, including columns, are also typical and are aatm to optimization by competent personnel.
Run a chromatogram of each component to check on its given composition. Enter the sample and obtain a response through methane Note 5. This gives the Relative Molar Response factor RMRi for component 0- The reference component must be present in the same instrumental sequence except HexanesH- as the referenced components.
Methane should be in a 1-L cyHnder at MPa atm pressure. Enter the sample, and backflush heavy components when appropriate. This eliminates the need for a multicomponent standard for daily calibration. NOTE 6—Most modem chromatographs have valve ovens that can be temperature controlled.
For these components, a mixture with nitrogen or methane can d1945-30 used to establish a partial pressure that can extend the total pressure to kPa mm Hg. The percent nitrogen is multiplied by 0. Check this average by a second group o f tracings.
The amount of purging required must be established and verified for each instrument. D o not use a fixed zero line as the baseline, but use the actual observed baseline.
Moisture on the column w i l l enlarge the reverse flow peak. Enter a 1- to 5-mL sample and ashm the response for helium, followed by hydrogen, which will be just ahead of oxygen Note 5. A strip-chart recorder w ith an offset zero is desirable. Maintain all samples above the hydrocarbon dew point. The resolution R must be 1. I f increased accuracy of the hexanes and heavier portions of the analysis is required, a larger sample size may be used see Test Method D Warning—Some components, such as satm dioxide, hydrogen sulfide, and hexanes and higher hydrocarbons, may be partially or completely removed by the water.
See Table 2 and Table 3. A 5A column can be used if a pre-cut column is present to remove interfering hydrocarbons.