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"Portable FTIR Method for Determination of Gaseous Pollutants in Exhaust Gas from Stationary Pollution Sources" released

 Last Update: 2022-05-01
 Source: Internet
 Author: User

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[ Policies and Regulations of Chemical Machinery and Equipment Network ] Recently, the Ministry of Ecology and Environment issued "Portable Fourier Transform Infrared Spectrometry for Determination of Gaseous Pollutants (SO2, NO, NO2, CO, CO2) in Exhaust Gases from Stationary Pollution Sources" (HJ1240-2021), and published in 2022 Effective June 1st, 2018
.

Chemical Machinery and Equipment Network Policies and Regulations Chemical Machinery and Equipment

In order to implement the Environmental Protection Law of the People's Republic of China and the Air Pollution Prevention and Control Law of the People's Republic of China, prevent and control ecological environment pollution, improve the quality of the ecological environment, and Determination methods, the development of this standard
.

This standard is published for the first time
.
This standard refers to GB/T 16157 Determination of particulate matter in stationary pollution sources and sampling methods for gaseous pollutants; HJ 75 Technical specifications for continuous monitoring of flue gas (SO2, NOx, particulate matter) emissions from stationary pollution sources; HJ/T 373 Quality assurance and monitoring of stationary pollution sources Quality Control Technical Specifications (Trial); HJ/T 397 Technical Specifications for Stationary Source Waste Gas Monitoring; HJ 1011 Technical Requirements and Detection Methods for Portable Fourier Infrared Monitors for Volatile Organic Compounds in Ambient Air and Waste Gas
.

This standard specifies a portable Fourier transform infrared spectrometry method for the determination of gaseous pollutants (SO2, NO, NO2, CO, CO2) in waste gas from stationary pollution sources
.
This standard will be implemented from June 1, 2022
.

Method principle:

When infrared light with a continuous wavelength irradiates the molecules of the substance to be tested, the infrared light with the same natural vibration frequency of the molecule is absorbed, and an infrared absorption spectrum with the wave number as the abscissa and the absorbance as the ordinate is obtained
.
Different substances absorb infrared light differently, and the wave numbers of characteristic absorption peaks are different
.
Fourier transform infrared spectroscopy is to convert the light emitted by the infrared light source into interference light through a Michelson interferometer, and then irradiate the gas sample with the interference light to obtain an infrared interferogram.
The infrared absorption spectrum is obtained by the computer system after Fourier transform processing
.
By comparing the infrared absorption spectrum of the gas sample with the infrared absorption spectrum of the standard substance in the standard spectrum library, the sample can be qualitatively analyzed
.
Under certain conditions, the characteristic absorption peak intensity and concentration of the target compound in the infrared absorption spectrum follow the Lambert-Beer law, and the target compound can be quantitatively analyzed according to the absorption peak intensity
.

　　Instruments and Equipment:

　　1.
Fourier transform infrared gas analysis system

　　1.
1 System Composition

　　Fourier transform infrared gas analysis system is generally composed of sampling unit, preprocessing device, analyzer and data processing unit
.
Among them, the sampling unit includes a sampling tube (including a particulate filter , with heating and heat preservation functions), an air duct, an air pump, etc.
; the pretreatment device can choose a constant temperature heating device with a heating temperature of ≥180 °C; the analyzer consists of an infrared light source and an interferometer.
, sample chamber and detector, etc.
; data processing unit includes computer, analysis software and reference spectrum
.

filter

　　1.
2 Performance requirements

　　1.
2.
1 Indication error: when the calibration range of SO2, NO, NO2, and CO is greater than 60 μmol/mol, the relative error is within ±5%; when the calibration range is ≤60 μmol/mol, the absolute error is within ±3 μmol/mol ; The relative error of CO2 is within ±5%
.

　　1.
2.
2 System error: when the calibration range of SO2, NO, NO2, and CO is greater than 60 μmol/mol, the relative error is within ±5%; when the calibration range is less than or equal to 60 μmol/mol, the absolute error is within ±3 μmol/mol; The relative error of CO2 is within ±5%
.

　　1.
2.
3 Zero drift: within ±3%
.

　　1.
2.
4 Range drift: within ±3%
.

　　1.
2.
5 Analyzer: the wavenumber range should include at least 900 cm-1 ~ 4000 cm-1; the total optical path length should meet the minimum detection limit requirements of each target compound in this standard; the spectral resolution should ensure that the target in the gas sample can be separated.
The compounds are separated from the infrared absorption peaks of other coexisting species
.

　　1.
2.
6 The particulate filter and other properties of the instrument shall meet the technical requirements of HJ 1011 for Type II instruments
.
The material of the air duct and pretreatment device should be materials that are resistant to high temperature, anti-corrosion, non-adsorption, and non-reactive with the target compound
.

　　2.
Standard gas cylinder

　　Equipped with an adjustable pressure reducing valve, an adjustable rotor flowmeter and an air pipe made of polytetrafluoroethylene, and the materials of each component should avoid physical adsorption or chemical reaction with the target compound
.

Flowmeter

　　Sample determination:

　　1.
Place the front end of the sampling tube in the exhaust cylinder and as close to the center as possible, and seal the gap around the sampling hole tightly to prevent air leakage
.

　　2.
Start the air pump, and measure at the sampling flow specified by the instrument.
After the instrument display is stable, save the measurement data in minutes, measure continuously for 5 min to 15 min, and take the average value as a measurement value
.

　　3.
After the measurement of the sample at the same point, clean the analysis system with the zero point gas, so that the indication value of the instrument returns to the vicinity of the zero point and remains stable
.

　　4.
Before shutting down, clean the analysis system with zero-point gas to make the indication value of the instrument return to the vicinity of the zero point and keep stable, then turn off the air pump, then turn off the analyzer and preprocessing device, and finally disconnect all parts of the analysis system to end the measurement.

.

　　This standard applies to the determination of gaseous pollutants (SO2, NO, NO2, CO, CO2) in waste gas from stationary pollution sources
.

　　The detection limit of SO2, NO and CO are all 1mg/m3, and the lower limit of detection is 4mg/m3; the detection limit of NO2 is 3mg/m3, and the lower limit of detection is 12mg/m3; the detection limit of CO2 is 1g /m3, the lower limit of determination is 4g/m3
.

　　Original title: "Portable FTIR Method for Determination of Gaseous Pollutants in Exhaust Gas from Stationary Pollution Sources" released

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