HJ 38-2017Stationary Source Emission - Determination of Total Hydrocarbons, Methane and Nonmethane Hydrocarbons - Gas Chromatography (English PDF)

3.1 Total Hydrocarbons (THC)

Total hydrocarbons refer to the sum of gaseous organic compounds that respond on the hydrogen flame ionization detector of the gas chromatograph under the determination conditions specified in this Standard.

5.1 De-hydrocarbon air. content of total hydrocarbons (oxygen peak included) <= 0.40

mg/m3 (calculated by methane); or, determine on the methane column, no other peaks except the oxygen peak.

5.3 Nitrogen. purity >= 99.999%.

5.4 Hydrogen. purity >= 99.99%.

5.5 Air. use a purification tube for air purification.

6.6 Chromatographic column

6.7 Sample heating device. the sample can be placed in it and heated to not lower than

120 °C; the temperature control accuracy is ± 5 °C.

7.1 Sample Collection

7.1.1 Collection with air bag

In accordance with Figure 1, connect the sampling device. The determination of the sampling location, sampling point, sampling frequency and sampling time of exhaust gas emitted from stationary sources, as well as the determination of exhaust parameters and the sampling operations shall comply with the relevant stipulations of

GB/T 16157, HJ/T 397 and HJ 732.

7.1.2 Collection with glass syringe

In accordance with Figure 2, connect the sampling device. The determination of the sampling location, sampling point, sampling frequency and sampling time of exhaust gas emitted from stationary sources, as well as the determination of exhaust parameters and the sampling operations shall comply with the relevant stipulations of

GB/T 16157 and HJ/T 397.

7.2 Transportation of Blank Sample

Bring the sampling container filled with de-hydrocarbon air (5.1) to the sampling site.

Send it back to the laboratory for analysis together with the samples collected in the same batch.

7.3 Sample Storage

The glass syringe for sample collection shall be handled with care to prevent it from being damaged. Maintain the needle tip downwards and place it in the sample storage box for storage and transportation.

8.1 Reference Conditions of Chromatographic Analysis

8.2 Calibration

8.2.1 Preparation of calibration series

Take a 100 mL glass syringe (beforehand, put in a piece of rigid polytetrafluoroethylene sheet) or a 1 L air bag as a container.

8.2.2 Draw a calibration curve

From low concentration to high concentration, respectively draw 1.0 mL of the calibration series (8.2.1); inject it into the gas chromatograph (6.4) to respectively determine total hydrocarbons and methane. Take the concentration of total hydrocarbons and methane (µmol/mol) as the x-coordinate; take the corresponding peak area as the y-coordinate; respectively a calibration curve of total hydrocarbons and methane.

8.2.3 Standard chromatogram

Under the reference conditions (8.1) of chromatographic analysis provided in this

8.3 Sample Determination

8.3.1 Determination of total hydrocarbons and methane

Take 1.0 mL of the sample to be tested. In accordance with the same operating steps and analysis conditions as the calibration curve, determine the peak area of total hydrocarbons and methane in the sample.

8.3.2 Determination of oxygen peak area

Take 1.0 mL of the de-hydrocarbon air (5.1). In accordance with the same operating steps and analysis conditions as the calibration curve, determine the oxygen peak area on the total hydrocarbon column.

9.1 Result Calculation

The mass concentration of total hydrocarbons and methane in the sample shall be calculated in accordance with Formula (1).

9.2 Result Expression

When the determined result is less than 1 mg/m3, it shall be retained to two decimal places; when the determined result is greater than or equal to 1 mg/m3, 3 significant figures shall be retained.

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