Application of Gas Chromatography in Air Separation Industry

2023-08-23

Air separation industry

Industrial gases include oxygen, nitrogen, argon, neon, helium, hydrogen, carbon dioxide, acetylene, etc. These gases are widely used in metallurgy, petrochemical, semiconductor, aerospace and other industries. The air separation process is a set of industrial equipment used to separate the various components in the air and produce industrial gases such as oxygen, nitrogen, and argon. In recent years, with the development of the economy, the domestic air separation equipment has gradually developed to be large-scale, and it needs to be equipped with gas analyzers at the same time. Gas analysis instruments can directly control the quality of the production process of the air separation unit, provide various parameters for the production process, and enable the staff to know the gas composition of each process control point in the production process in a timely manner. It is an important equipment to improve product output and quality , It is also an important guarantee for the safe operation of the air separation unit.

High Purity Gas Analysis Solutions

This solution includes trace analysis methods suitable for different high-purity gas applications: "GBT 14599-2008 Pure Oxygen, High-Purity Oxygen and Ultra-Pure Oxygen", "GBT 8979-2008 Pure Nitrogen, High-Purity Nitrogen and Ultra-Pure Nitrogen", The introduction of national standards such as "GBT 4844-2011 Pure Helium, High-Pure Helium and Ultra-Pure Hydrogen" puts forward strict requirements for gas monitoring in the air separation industry. In order to ensure the stable operation of the air separation unit, Optosky has developed its own patented helium ionization detector based on years of industry experience to provide gas analysis solutions for the air separation industry, and to achieve trace level detection of impurities in the air separation industry gas. For trace-level gas analysis of high-purity gases, a gas chromatograph with a customized flow path system is equipped with different detectors to measure multiple compounds through one needle injection. It is efficient, fast, labor-saving, and low in analysis cost. It is suitable for Air separation manufacturing risk early warning, emergency monitoring, daily inspection and scientific research inspection.

Gas Chromatography Core Technology

DID (Helium Ionization, Helium Discharge Ionization) is a general purpose detector. The response factor of a substance in DID is related to its ionization energy. The principle is that under the action of DC high voltage, helium is ionized to form high-energy photons γ, and high-energy photons with high energy enter the ionization chamber to ionize the measured substance, and at the same time ionize the He carrier gas to form metastable helium (He*) It also impacts the measured substance to ionize it, and the ions are collected by the collector to form a signal. The structure of the discharge ionization detector is shown in the figure:

Schematic diagram of the composition principle of a discharge ionization detector (DID)

Discharge chamber： He525V static high pressure→He++e-+γ
ionization chamber： γ+M→M++e-

γ+He→He*

He*+M→He+M++e-

The detector has a unique design, which is divided into upper and lower chambers, so that the discharge chamber is completely separated from the ionization chamber, reducing the pollution of the measured gas and ensuring a high degree of stability of the detector. The DID discharge detector has a good linear relationship at low concentrations, and can detect all inorganic and organic gas components including Ne. See the previous description for the patent certificate.

Outline drawing of GM 816 gas chromatograph

Description of application standards

《GB/T 3634.2-2011 Pure Hydrogen, High Purity Hydrogen and Ultra Pure Hydrogen》The standards are as follows:

project	index
hydrogen（H2）（Volume fraction）/10-2 ≧	99.99	99.999	99.9999
oxygen（O2）（Volume fraction）/10-6 ≤	5	1	0.2
argon（Ar）（Volume fraction）/10-6 ≤	supply and demand agreement	supply and demand agreement	0.2
nitrogen（N2）（Volume fraction）/10-6 ≤	60	5	0.4
carbon monoxide（CO）（（Volume fraction）/10-6 ≤	5	1	0.1
carbon dioxide（CO2）（（Volume fraction）/10-6 ≤	5	1	0.1
methane（CH4）（（Volume fraction）/10-6 ≤	10	1	0.2
water（H2O）（Volume fraction）/10-6 ≤	10	3	0.5
Total content of impurities（Volume fraction）/10-6 ≤	--	10	1

PSAHydrogen Product Quality Standards（GB/T37244-2018、SAE J2719、ISO 14687 for the same standard）

Project name	index
Hydrogen purity (mol fraction)	≥99.97 %
Total non-hydrogen gas	300 mmol/mol
Maximum concentration of a single type of impurity
water（H2O）	5 mmol/mol
Total hydrocarbons (as methane)	2 mmol/mol
oxygen（O2）	5 mmol/mol
helium（He）	300 mmol/mol
total nitrogen （N2）and argon（Ar）	100 mmol/mol
carbon dioxide（CO2）	2 mmol/mol
carbon monoxide （CO）	0.2 mmol /mol
Total sulfur (according to H2S)	0.004 mmol/mol
formaldehyde（HCHO）	0.01 mmol/mol
formic acid（HCOOH）	0.2 mmol/mol
ammonia（NH3）	0.1 mmol/mol
Total halogen compounds (calculated as halide ions)	0.05 mmol/mol
Maximum particle concentration	1 mg/kg