HJ/T 56-2000Determination of sulphur dioxide from exhausted gas of stationary source - Iodine titration method (English PDF)

Foreword

This Standard specifies the iodine titration method to determine the concentration of

sulphur dioxide from exhausted gas of stationary source as well as its total emission.

During the formulating, this Standard referred to the national standard. GB/T 16157-

1996 "The determination of particulates and sampling methods of gaseous pollutants

emitted from exhaust gas of stationary source" and parts of "Air and waste gas

monitoring analysis method" issued by State Environmental Protection Administration

in 1990. It also referred to relevant sampler's technical indicators and domestic-foreign

enterprise standards.

This Standard was proposed by Department of Science, Technology and Standards of

State Environmental Protection Administration.

This Standard was drafted by China National Environmental Monitoring Center.

This Standard shall be interpreted by State Environmental Protection Administration.

Determination of sulphur dioxide from exhausted gas

of stationary source - Iodine titration method

1 Scope

This Standard specifies the iodine titration method to determine the concentration of

sulphur dioxide from exhausted gas of stationary source as well as the determination

of sulfur dioxide emission rate.

2 Normative references

The following standard contains the provisions which, through reference in this

Standard, constitute the provisions of this Standard. It has the same effect as this

Standard.

GB/T 16157-1996 The determination of particulates and sampling methods of

gaseous pollutants emitted from exhaust gas of stationary source

3 Determination method-principle, determination range and

determination error

Sulfur dioxide from exhausted gas is absorbed by the mixed solution of ammonium

sulfamate. Use iodine standard solution to titrate. Calculate the sulfur dioxide

concentration according to the titration. Reactions are shown as follows.

Determination range. 100 ~ 6000 mg/m3; within the determination range, the batch

error of the method shall not be greater than ± 6%.

4 Influential factors

8 Determination

After sampling, it shall titrate the sample as soon as possible. The sample shall not be

placed for more than 1h. Move all samples in two absorption bottles into the iodine

bottle. Use a small amount of absorption solution (6.1) to respectively wash the

absorption bottle twice. Move the washing solution into the iodine bottle as well. Shake

well. When adding 50 ml of 2 g/L starch solution (6.3), use 0.010 mol/L iodine standard

solution (6.8) to titrate to blue. Record the consumption V (ml).

Separately, take the absorption solution (6.1) of same volume. Conduct blank titration

in the same method. Record the consumption V0 (ml).

If the sulfur dioxide concentration of the gas is high, it shall take part of absorption

solution to titrate. At this time, the result calculated according the equation listed in

Clause 9 shall be divided by the ratio of partial absorption solution accounting for total

absorption solution.

9 Calculation

Where,

c' - sulfur dioxide concentration of dry gas under standard conditions (mg/m3);

c(1/2 I2) - concentration of iodine stock solution (mol/L);

Vnd - sampling volume of dry gas under standard conditions (L);

10 Calculation of sulfur dioxide emission rate