HJ 57-2017Stationary source emission - Determination of sulfur dioxide - Fixed potential by electrolysis method (English PDF)

1 Scope

This standard specifies the fixed potential electrolysis method for the determination of sulfur dioxide in stationary source emission.

This standard applies to the determination of sulfur dioxide in stationary source emission.

The detection limit of this standard is 3 mg/m3.The lower limit of determination is 12 mg/m3.

2 Normative references

The contents of this standard refer to the following documents or their terms.

For undated references, the valid version applies to this standard.

GB/T 16157 The determination of particulates and sampling methods of gaseous pollutants emitted from exhaust gas of stationary source

HJ 75 Specifications for continuous emissions monitoring of SO2, NOX, and particulate matter in the flue gas emitted from stationary sources

HJ 76 Specifications and test procedures for continuous emission monitoring system for SO2, NOX and particulate matter in flue gas emitted from stationary

HJ/T 46 Technical conditions of detector of sulfur dioxide concentration for constant potential electrolysis method

HJ/T 373 Technical specifications of quality assurance and quality control for monitoring of stationary pollution source (on trial)

HJ/T 397 Technical specifications for emission monitoring of stationary source

3 Terms and definitions

3.1

Zero gas

The gas which has no measurement component or less than the specified value, meanwhile other component’s concentrations do not interfere with the measurement component results or the interference from the resulting measurement component is negligible.

3.3

Calibration error

The error between the measurement result of standard gas as directly led into the analyzer and the concentration value of the standard gas.

3.4

System bias

The percentage of the difference between the measurement result of the standard gas as directly led into the analyzer and the measurement result of the gas as led into the instrument via the sampling tube to the calibration span.

3.5

Zero drift

Before and after the test, the percentage of the difference between the analyzer for the measurement results of same zero gas, to the calibration span.

4 Principle of method

The sample is taken into a sensor consisting mainly of an electrolytic cell, an electrolyte, electrodes (sensitive electrode, reference electrode, counter electrode). Sulfur dioxide diffuses through the permeable membrane to the surface of the sensitive electrode; an oxidation reaction occurs on the sensitive electrode.

5 Interference and elimination

5.1 The particulate matter, moisture and sulfur trioxide in the gas to be tested are easy to condense on the surface of the sensor’s permeable membrane and cause damage to the sensor, which affects the determination; it shall be filtered by a dust filter device, a dehumidifier, a mist filter, etc. to eliminate the influence.

5.3 Carbon monoxide’s interference is significant, so the concentration of carbon monoxide must be determined simultaneously when measuring the sample. When the concentration of carbon monoxide does not exceed 50

µmol/mol, the sample can be determined by this standard.

6 Reagents and materials

7 Instruments and equipment

8 Sampling and determination

9 Calculation and representation of results