HJ 57-2017 PDF in English
HJ 57-2017 (HJ57-2017) PDF English
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| HJ 57-2017 | English | 145 |
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Stationary source emission - Determination of sulfur dioxide - Fixed potential by electrolysis method
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| HJ/T 57-2000 | English | 70 |
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Determination of sulphur dioxide from exhausted gas of stationary source - Fixed-potential electrolysis method
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Standards related to (historical): HJ 57-2017
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HJ 57-2017: PDF in English HJ 57-2017
ENVIRONMENTAL PROTECTION STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Replacing HJ 57-2000
Stationary source emission - Determination of sulfur
dioxide - Fixed potential by electrolysis method
ISSUED ON: NOVEMBER 28, 2017
IMPLEMENTED ON: JANUARY 01, 2018
Issued by: Ministry of Environmental Protection
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Principle of method ... 7
5 Interference and elimination ... 7
6 Reagents and materials ... 8
7 Instruments and equipment ... 8
8 Sampling and determination ... 9
9 Calculation and representation of results ... 10
10 Precision and accuracy ... 11
11 Quality assurance and quality control ... 12
12 Precautions ... 13
Appendix A (Informative) Carbon monoxide interference test - Dynamic aeration
matrix test method ... 15
Appendix B (Informative) Instrument performance review results before and
after measurement ... 22
Stationary source emission - Determination of sulfur
dioxide - Fixed potential by electrolysis method
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
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:
This results in an ultimate diffusion current (i). Under the specified working
conditions, the number of electron transfer (Z), Faraday constant (F), gas
diffusion area (S), diffusion coefficient (D), thickness of diffusion layer (δ) are
constant; the magnitude of the ultimate diffusion current (i) is proportional to the
sulfur dioxide’s concentration (c), so it may use the ultimate diffusion current (i)
to determine the sulfur dioxide’s concentration (c).
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.
5.2 Ammonia, hydrogen sulfide, hydrogen chloride, hydrogen fluoride, nitrogen
dioxide, etc. will cause some interference to the determination of samples. It
may use phosphoric acid absorption, lead acetate adsorption, gas filter filtration
and other measures to reduce interference.
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. When the
concentration of carbon monoxide exceeds 50 μmol/mol, the interference test
of carbon dioxide shall be carried out before the initial use of the sulfur dioxide
analyzer (see Appendix A). Within the range of the highest concentration of
sulfur dioxide and the highest concentration of carbon monoxide as determined
by the interference test, the sample can be determined by this standard.
It is equipped with adjustable pressure reducing valve, adjustable rotor
flowmeter, air duct.
7.3 Gas bag
Used to calibrate the analyzer by air bag method. The volume is 4 L ~ 8 L; the
lining material shall be selected from the aluminum-plastic composite film,
polytetrafluoroethylene film and other inert materials that have little influence
on the measured components.
7.4 Emission parameter tester
An instrument capable of testing parameters such as moisture content, flue
gas’s temperature, flue gas’s pressure, flue gas’s flow rate, flow rate.
7.5 Carbon monoxide measuring device
A device or apparatus capable of measuring the concentration of carbon
monoxide in an emission.
8 Sampling and determination
8.1 Determination of sampling points and sampling frequency
According to GB/T 16157, HJ/T 397, HJ/T 373, HJ 75 and HJ 76 and related
requirements, determine the sampling position, sampling point, sampling
frequency.
8.2 Inspection of tester’s air tightness
According to the instruction manual of the instrument, connect the analyzer,
sampling tube, air duct, etc. correctly. After reaching to the working conditions
of the instruments, check the airtightness according to GB/T 16157 or HJ/T 46.
If the inspection fails, it shall find the leakage and repair it, until the inspection
is qualified.
8.3 Calibration of analyzer
8.3.1 Zero calibration
Lead zero gas into the analyzer to calibrate the instrument’s zero point.
8.3.2 Calibration of range
Lead the sulfur dioxide standard gas into the analyzer for measurement. If the
calibration error meets the requirements of 7.1.2 a), the analyzer is available;
otherwise, it requires calibration. The calibration method is as follows:
again to calculate the calibration error and system bias. If the calibration error
and system bias meet the requirements of 7.1.2 a) and b), the determination
result of the sample is valid; otherwise, the determination result of the sample
is invalid.
Note: It may use the inspection of the calibration error of the whole system including
the sampling tube, the air guiding tube and the dehumidification device to substitute
the inspection of the calibration error of the analyzer and the system bias [the
evaluation follows the requirements 7.1.2 a)].
11.3 The sample measurement result shall be between 20% and 100% of the
calibration span of the instrument. Otherwise, it shall re-select the calibration
span.
11.4 If the analyzer does not carry out the carbon monoxide’s interference test
or the carbon monoxide’s interference test fails, the minute data of the sulfur
dioxide concentration measured when the concentration of carbon monoxide in
the exhaust gas exceeds 50 μmol/mol shall be excluded as invalid data. If the
analyzer has passed the carbon monoxide’s interference test, the minutes data
of the sulfur dioxide concentration as measured when the concentration of
carbon monoxide in the emission exceeds the highest concentration of carbon
monoxide determined by the interference test, as well as the minutes data of
sulfur dioxide concentration exceeding the highest concentration of sulfur
dioxide determined by the interference test shall be taken as invalid data and
are rejected. For one measurement value, it shall obtain not less than 5 minutes
data of valid sulfur dioxide concentrations.
11.5 After the analyzer is replaced with a sulfur dioxide sensor, it shall repeat
the interference test.
11.6 At least one zero drift and span drift check shall be performed every month
and shall comply with the requirements of 7.1.2 c) and d). Otherwise, the
instrument shall be maintained or repaired in a timely manner.
11.7 The service life of the fixed potential electrolysis sensor is generally less
than 2 years, which shall be replaced in time after expiration. When calibrating
the sensor, if the dynamic range is found narrowed, the upper limit of the
measurement cannot reach the full scale value, or when the calibration span of
the instrument is rechecked, the calibration error exceeds the requirement of
7.1.2 a), it indicates that the sensor has failed and shall be replaced in time.
12 Precautions
12.1 The analyzer shall be operated under the conditions of its specified
ambient temperature, ambient humidity, etc.
Appendix A
(Informative)
Carbon monoxide interference test - Dynamic aeration matrix test
method
A.1 Reagents and materials
A.1.1 Sulfur dioxide standard gas
Commercially available certified standard gas, uncertainty ≤ 2%.
A.1.2 Nitrogen
Purity ≥ 99.99%.
A.1.3 Carbon monoxide standard gas
Commercially available certified standard gas, uncertainty ≤ 2%.
A.2 Instruments and equipment
A.2.1 Sulfur dioxide analyzer
Same as 7.1.
A.2.2 Carbon monoxide analyzer
Same as 7.5.
A.2.3 Dilution gas distribution device
It can dynamically distribute gas to standard gases such as sulfur dioxide,
carbon monoxide, nitrogen. It has at least 3 input channels and 1 output channel.
The mass flow meter controls the gas flow of each input and output channel,
wherein the mass flow meter of the input channel shall not below 5 L/min, the
mass flowmeter of the output channel shall be not less than 10 L/min, the
accuracy shall be at or better than ±2%.
A.3 Operation steps
A.3.1 Instrument preparation
A.3.1.1 Inspection of instrument’s air tightness
Check the air tightness of the sulfur dioxide analyzer and the carbon monoxide
analyzer, to ensure that the system is airtight.
A.3.1.2 Instrument calibration
Use the zero gas to calibrate the zero point of the sulfur dioxide analyzer and
the carbon monoxide analyzer. Use the sulfur dioxide standard gas and carbon
monoxide standard gas to respectively check or calibrate the instrument.
A.3.2 Carbon monoxide’s interference test procedure
A.3.2.1 Determination of concentration level of sulfur dioxide in mixed gas
According to the range of the fixed potential electrolysis sensor used in the
sulfur dioxide analyzer, respectively use the (10 ± 2)%, (20 ± 2)%, (40 ± 2)%,
(60 ± 2)%, (80 ± 2)%, 95% ~ 100% of the range value as a concentration of
sulfur dioxide in the mixed gas, to conduct carbon monoxide interference test.
A.3.2.2 Calculation of volume of mixed gas
Use the minimum concentration level of sulfur dioxide in the mixed gas
determined by A.3.2.1 as a target, based on the standard gas concentration of
sulfur dioxide and the standard gas concentration of carbon monoxide used,
calculate the volume of mixed gas of sulfur dioxide, carbon monoxide, nitrogen
and other standard gases.
A.3.2.3 Determination of initial value of sulfur dioxide concentration in
mixed gas
According to the calculated mixed gas volume of standard gas, lead only the
nitrogen gas and sulfur dioxide standard gas into the dilution gas distribution
device; after the gas mixture is stabilized, use a sulfur dioxide meter to measure
the sulfur dioxide concentration in the mixed gas, record it as the initial value of
the sulfur dioxide concentration in the mixed gas (CSO2-t0).
A.3.2.4 Determination of sulfur dioxide concentration under the
interference of series carbon monoxide concentration
According to the calculated mixed gas volume of the standard gas, keep the
mixed gas volume of sulfur dioxide standard gas unchanged. Gradually reduce
the mixed gas volume of nitrogen gas. Gradually increase the mixed gas
volume of carbon monoxide standard gas (but the sum of the mixed gas volume
of nitrogen gas and carbon monoxide standard gas must be kept equal to mixed
gas volume of nitrogen in A.3.2.3). Ensure that the concentration level of the
sulfur dioxide in the mixed gas mixture is stable and unchanged, but the
concentration of carbon monoxide can, in the range of 100 μmol/mol to a higher
concentration range, be increased gradually at a concentration difference of
(200 ~ 2000) μmol/mol [to form a series of carbon monoxide interference
concentrations close to (100, 300, 500, 1000, 1500, 2000, 3000, 4000, 5000,
6000, 7000, 8000, 10000, 12000, 15000, 20000) μmol/mol]. At each
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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