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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Close the n-pentane cyhnder valve and open Cylinder A valve to admit the n-pentane from the connection and then close the valve on Cylinder A.
40 CFR 600.011 – Incorporation by reference.
d19450-3 Permission rights to photocopy the standard may also be secured from the ASTM website www. Close the cylinder valves, disconnect, and aztm Cylinder A to determine die weight of mixture that was not transferred to the L cylinder.
The percent nitrogen is multiplied by 0. Diluted dry air is a suitable standard for oxygen and nitrogen see 8. It is helpful to retain a sample containing some hexanes and heavier for periodic checking. For instance, propane can 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.
Obtain a response on dry air for nitrogen and oxygen, i f desired. Replace the drying agent after about one half of the material has become spent. The area of reverse flow peak may be measured by planimeter or geometric construction. Baseline tracking with tangent skim peak detection is recommended. The sample-entry system must be vacuum tight.
Obtain a corresponding chromatogram of the reference standard. Either the average of the two consecutive checks, or d19450-3 latest check agreeing within the repeatability limits of the previous check on each component d1945-003 be used as the reference standard for all subsequent runs until there is a change in instrument operating conditions. Also, the richer the gas, the worse the problem. The composition of the sample is calculated by comparing either the peak heights, or the peak areas, or both, with the corresponding values obtained with the reference standard.
Run a sample o f the mixture r1945-03 kPa mm H g absolute pressure and obtain the helium peak. Maintain all samples above the hydrocarbon dew point. Enter a 1- to 5-mL sample and record the response for helium, followed by hydrogen, which will be just ahead of oxygen Note 5.
40 CFR – Incorporation by reference. | US Law | LII / Legal Information Institute
W i t h either type manometer the m m scale can be read more accurately than the inch scale. Last prewous edition approved in as The values given asfm parentheses are mathematical conversions to SI units that are provided d11945-03 information only and are not d1945-30 standard.
It is strongly recommended in the absence of valve ovens to mount the gas samphng valve in the chromatograph oven and operate at the column temperature. Enter the sample and obtain a response through methane Note 5. 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.
Make calculations on ethane and heavier components in the same manner as for the complete analysis method. The amount of purging required must be established and verified for each instrument. A superscript epsilon E indicates an editorial change since the last revision or reapproval. Usually 1 m of 6-mm tubing astk w ith to mesh molecular sieves is adequate, i f changed w ith each cylinder o f carrier gas.
Connect Cylinder B to the L cylinder with as short a clean, small-diameter connector as possible.
The slope a, can be calculated by: Samples w i t h up to one atmosphere o f pressure can be entered. I f all columns are chosen to operate at the same temperature, then stabilization time between changing columns will be minimized. Although a strip-chart recorder is not required when using electronic integration, it is highly desirable for evaluation of instrument performance.
All components in the reference standard must be homogenous in the vapor adtm at the time of use.
Weigh Cylinder A after each addition to obtain the weight of the component added. I f changes occur in these operating conditions, all of the components will be affected equally and the calculated response factors will shift accordingly. Separation of carbon dioxide must be sufficient so that a 0. Obtain a corresponding response on the reference standard.
The connection between V, and Vj in Fig. I f i n doubt about the composition, check the n-pentane and isopentane values w ith pure components by the procedure prescribed in Annex A 2.
The detector temperature shall be equal to or greater than the maximum column temperature. NOTE 1 — T h e sample size limitation of 0. This eliminates the need for a multicomponent standard for daily calibration. Convert the weight percent to mole percent. The test method can be used on any gas chromatograph using a thermal conductivity or thermistor detector. The fixed loop or section shall be so constructed that the total volume, including dead space, shall not normally exceed 0.
Heated lines may be necessary for high hydrocarbon content samples. Select a sample size in accordance with 8.