10. Procedure
10.1 Methane and Ethane - Typical operating conditions for the analyses for methane and ethane are summarized in Table 3. Slowly flush the sample to be analyzed through the gas sample valve on the chromatograph until all extraneous vapor has been purged from the sample loop. Turn the gas valve to introduce the sample into the carrier gas stream. Record the deflection of each component peak at the minimum attenuation or greatest sensitivity for maximum peak height. Fig. 3 shows a typical chromatogram obtained with the procedure and operating conditions as outlined. Measure the height of each peak from the baseline in millimetres. Both peak height and peak area need to be measured for methane since the area will be used for preparation of an acetylene calibration curve.
10.2 Carbon Dioxide - Typical operating conditions for the analysis for carbon dioxide are given in Table 3. Flush the sample to be analyzed through the gas sample valve on the chromatograph until all extraneous vapor has been purged from the sample loop. Turn the gas valve to introduce the sample into the carrier gas stream. Record the carbon dioxide peak at the greatest sensitivity for maximum peak height. Measure the height of each peak from the baseline in millimetres.
10.3 Propylene and Heavier - Typical operating conditions for the procedure for propylene and heavier components are given in Table 3. Flush the sample to be analyzed through the gas sample valve on the chromatograph until all the extraneous vapor has been purged from the sample loop. Turn the gas valve to introduce the sample into the carrier stream. Record the peaks of each component at maximum sensitivity for maximum peak height. Fig. 1 shows a typical chromatograph obtained with the procedure and conditions described. Measure the height of each peak from the baseline as formed by the tailing of the ethylene peak.
10.4 Acetylene - Typical operating conditions for the analysis for acetylene are given in Table 3. Flush the sample to be analyzed through the gas sample valve on the chromatograph until all extraneous vapor has been purged from the sample loop. Operate the gas valve to introduce the sample into the carrier gas stream. Measure the peak areas of the methane and acetylene peaks. Fig. 4 shows a typical chromatograph obtained with the procedure and conditions outlined.
11. Calculation
11.1 Carbon Dioxide, Methane, Ethane, Propylene, and Heavier - Calculate the mol percent of each component present in the sample as follows:
C = D x F
where:
C = concentration of component, mol% ,
D = peak height of the component, mm, and
F = calibration factor of component as determined in 9.3.1.
11.2 Acetylene - Calculate the mol percent of acetylene in the sample as follows:
C = A x Fa x (28/26)
where:
C = concentration of acetylene, mol% ,
A = area of the acetylene peak, and
Fa = area calibration factor as determined in 9.3.2.
11.3 Ethylene - Calculate the mol percent of ethylene in the sample by adding the concentration of all impurities and subtract from 100.