BS EN 15984-2011 pdf download.Petroleum industry and products Determination of composition of refinery heating gas and calculation of carbon content and calorific value Gas chromatography method.
2) Analysis system 2
The second analysis system separates non•condensable gases, carbon dioxide, and hydrocarbons with two carbon atoms and hydrogen sulfide with helium (3.1.2) as the carrier gas and a TCD as a detector. After a pre-separation on a porous polymer column (column 3) propane and higher hydrocarbons are back flushed and vented. See Figure A.5 for details..
When the inert gases (02/Ar, N2, CH4 and CC) are on the molecular sieve 13X column. this column is isolated.
Carbon dioxide, the Chydrocarbons and hydrogen sulfide are eluted from the porous polymer column
(column 4) and are detected. The C2-hydrocarbons from this fraction are not used for quantification. After this
the molecular sieve 13X column (column 6) is eluted and the components are determined on the TCD.
Methane is quantified on Analysis System 3.
3) Analysis system 3
The third analysis system separates and quantifies all hydrocarbons by an FID and hydrogen (3.1.1) or helium
(3.1.2) as the carrier gas. Two columns are used in series. From the methyl silicone column (column 1), the
components above a certain cut point e.g. n-pentane are back flushed and determined as a summed peak.
The hydrocarbons from the alumina oxide column, column 2, are then separated and quantified. See Figure
A.6 for details.
5.2 System configuration
The gas chromatographic system may consist of one or more gas chromatographs, with the possibility for isothermal or temperature programmed runs or both depending on the selected system configuration. A TCD and an FID shall be available.
A gas flow control system and gas sampling valves and switching valves are used.
Means for quantification shall be provided.
NOTE Optionally a vaporizer may be used.
5.3 Columns
A combination of packed and capillary columns is possible.
It shall be ascertained that a quantitative separation of all the components that need to be determined (see Table 1) is possible and that the summed total of C. is quantitative. Adequate separation is required between the components on all three separation systems.
If cyclopropane can be determined, it shall be summed to propene.
An example for a typical configuration is given in Annex A.
6 Calibration
6.1 General
Depending on the production procedure of the reference gas mixture, it might be necessary to convert the concentration units of the components in the calibration gas to (moL/mol) %.
Linearity of the detectors shall be checked according to Annex B.
If calibration s necessary. e.g. daily or for an analysis seties, a reference gas mixture shall be analysed. For each analysis system (see 5.1) at least one component. the reference component, needs to be calibrated. For example, for analysis system 1 hydrogen, for analysis system 2 nitrogen and for analysis system 3 propane. With these three components, an external calibration is done. The absolute response factor is calculated.
For all the other components. relative response factors will be used (see 6.3).
The relative response factor of the reference component will be set at 1,0.
As alternative all absolute response factors can be determined for all the components that need to be analyzed in a reference gas mixture. A check of this calibration can take place with a gas mixture with fewer components.
6.2 Absolute response factors
The determination of absolute response factors is possible when a repeatable injection is possible under constant analysis conditions. The ratio between concentration and peak area is determined and the absolute response factor is calculated with the following equation:
8 Expression of results
Report the carbon content in (gilOO g) of gas, to the nearest 0.01.
Report the caloritic value in (kJJl 00 g) of gas, to the nearest 0,01.
Report of the compositional analysis of the refinery heating gas in (molt 100 mol). to the nearest 0,01.
9 PrecisIon
9.1 General
The precision given in 9.2 and 9.3 was determined by statistical examination of interlaboratory test results in accordance with EN ISO 4259 [1].BS EN 15984-2011 pdf download.