GB/T 5832.1-2016Gas analysis - Determination of water - Part 1: Electrolytic method (English PDF)

1 Scope

This part of GB/T 5832 specifies the method of electrolysis for the determination of trace moisture in the gas, describes the principle of the method,

Equipment calibration, measurement matters, precision, results processing, test reports made a request.

This part applies to nitrogen, helium, neon, argon, krypton, xenon, carbon dioxide and other reactions that do not react with phosphorus pentoxide except for moisture absorption

Of the determination of trace water in the gas, the determination of the range. 0.1 × 10-6 ~ 1000 × 10-6 (volume fraction).

2 normative reference documents

The following documents are indispensable for the application of this document. For dated references, only the dated edition applies to this article

Pieces. For undated references, the latest edition (including all modifications) applies to this document.

General rules for sampling safety of industrial chemical products GB/T 3723

Gas analysis - Determination of trace moisture - Part 2. Dew point method GB/T GB/T 6379.2 Accuracy of measurement methods and results (accuracy and precision) - Part 2. Determination of standard measurement methods

The basic method of sex and reproducibility

3 Principle of the method

A DC voltage is applied between the two electrodes of the cell, and the moisture in the gas is absorbed by the damp film of the pool hygroscopic agent and is electrolyzed to

Hydrogen and oxygen. Known ambient temperature, ambient pressure and sample gas flow, according to Faraday's law of electrolysis and gas law can be derived from the electrolysis of water

The relationship between the flow and the moisture content in the gas sample is given by (1).

I =

Q × p × T0 × F × U × 10-4

3p0 × T × V0 (1)

Where.

I - the electrolysis current of water, the unit is microan (µA);

Q - sample air flow in milliliters per minute (mL/min);

p - environmental pressure in Pa (Pa);

T0 --- ambient temperature under standard conditions, 273.15K;

F - Faraday constant, 96485.3383C/mol;

U - moisture content of sample gas (volume fraction), × 10-6;

p0 --- ambient pressure under standard conditions, 101325Pa;

T --- the absolute temperature of the environment, the unit is open (K);

V0 --- molar volume of sample gas in standard state, expressed in liters per mole (L/mol).

It can be seen from the formula (1) that the size of the electrolysis current is proportional to the moisture content in the gas. Set at standard atmospheric pressure and 20 °C conditions, an ideal gas

The flow rate of the sample gas flows through the electrolytic cell at a flow rate of 100 mL/min. When the moisture content (volume fraction) of the sample gas is 1 × 10-6,

The electrolysis current of water is 13.4µA.