Determination of trace carbon monoxide, carbon dioxide and acetylene in ethylene and propylene for industrial use. Gas chromatography (1)

1 Scope

This standard specifies the gas chromatography method for the determination of trace amounts of carbon monoxide , carbon dioxide and acetylene in industrial ethylene and propylene .

This standard applies to ethylene , propylene content of not less than 1mL / m³ of carbon monoxide , of not less than 5mL / m³ of carbon dioxide and a determination is made not less than 1mL / m³ acetylene

This standard is not intended to address all safety issues related to its use

2 Normative references

The clauses in the following documents have become clauses of this standard after being quoted in this standard

GB/T3723 General rules for the safety of sampling of industrial chemical products (GB/T3723-1999, idt ISO 3165:1976)

GB/T 8170 Numerical rounding rules and the expression and determination of limit values

GB/T 13289 Industrial ethylene liquid and gas sampling method (GB/T 13289-1991, neq ISO 7382: 1986)

GB/T 13290 Industrial Propylene and Butadiene Liquid Sampling Method (GB/T 13290-1991, neq ISO 8563: 1987)

3 Method summary

The gas sample (or gasified liquid sample) is brought into a packed column or capillary column by a carrier gas injection means, so that carbon monoxide , carbon dioxide or acetylene separated from the other components

The reaction principle of the conversion of carbon oxide and carbon dioxide into methane is as follows:

4 Reagents and materials

4.

Nitrogen: Purity (volume fraction) ≥99.

Hydrogen: purity (volume fraction) ≥99.

4.

Oxygen, purity (volume fraction) ≥99.

4.

It is dried and purified by silica gel and 5A molecular sieve

4.

4.

4.

4.
4.
3 Carbon monoxide: commercial carbon monoxide with a purity (volume fraction) greater than 99%: pure carbon monoxide can also be prepared by the following method: carbon monoxide obtained by heating to 80°C on a water bath with formic acid and concentrated sulfuric acid is dehydrated by 50% lye and coke.
The gallic acid-base solution is purified and dried by calcium chloride and phosphorus pentoxide
.
After the air in the container is exhausted, it can be collected, with a purity of more than 99%
.

4.
4.
4 Carbon dioxide : commercial carbon dioxide with a purity (volume fraction) greater than 99%.
Pure carbon dioxide can also be prepared by the following method: reacting sodium carbonate with dilute hydrochloric acid and drying with concentrated sulfuric acid.
The purity can reach more than 99%
.

4.
4.
5 Acetylene: Purity (volume fraction) is greater than 90%.
Commercial acetylene with a purity of 99% or more can be used.
Pure acetylene can also be prepared by the following method: Take dozens of calcium carbide and put it into a 500mL three-door flask.
Pour into the separatory funnel on the three-door flask.
Add dropwise to the three-necked flask
.
The generated acetylene needs to be purified by 20% (mass fraction) sodium hydroxide solution and 20% (mass fraction) chromic anhydride solution
.
After the air in the container is exhausted, it can be collected
.
The purity of acetylene can reach more than 99%
.

4.
5 Standard sample

Standard samples of carbon monoxide, carbon dioxide or acetylene can be purchased from the market or prepared by themselves.
The bottom gas is nitrogen or ethylene (4.
4.
1) and should not contain carbon monoxide, carbon dioxide or acetylene, otherwise it should be revised
.
The content of carbon monoxide, carbon dioxide or acetylene in the standard sample should be close to the concentration in the sample to be tested
.

Related Links: Determination of Trace Hydrogen in Industrial Ethylene and Propylene Gas Chromatography (3)