Types and Application Fields of Industrial Gases

What are the different types of industrial gases? In national safety standards for industrial control gases, certain hazardous chemicals are commonly classified and labeled as Class 2 compressed gases and liquefied gases. These chemical substances refer to gases that can be compressed, liquefied, or dissolved under pressure.
I. Types of Industrial Gases
1. Compressed gases are gases whose molecules can be significantly brought closer together and compressed into a cylinder after being compressed or cooled. Such gases are referred to as compressed gases, including oxygen, nitrogen, argon, hydrogen, and others.
2. If a compressed gas is kept pressurized and appropriately cooled using liquefied gas, the compressed gas will turn into a liquid. Such gases are referred to as liquefied gases—for example, liquid chlorine, liquid ammonia, and liquid carbon dioxide.
3. High-pressure dissolved gases: In addition, there is another type of unstable gas that needs to be dissolved in a solvent and then stored in steel cylinders under pressure. Such gases are referred to as high-pressure dissolved gases, such as dissolved acetylene.
2. Use different types of industrial gases
1. Industrial gases used by general enterprises typically consist primarily of air separation gases such as oxygen, nitrogen, and argon, as well as synthesized gases like acetylene and carbon dioxide. Generally, these gases do not require extremely high purity levels; their primary applications lie in industries including metallurgy, petrochemicals, coal chemical engineering, steelmaking, shipbuilding, and heavy industry in China. The development of industrial gases generally encompasses gases such as oxygen, nitrogen, argon, neon, helium, krypton, xenon, hydrogen, carbon dioxide, acetylene, and natural gas.
2. Special gases refer to pure gases, high-purity gases, and multi-component mixtures of high-purity or ultra-high-purity gases. These special gases are widely used in fields such as electronics, power generation, petrochemicals, mining, iron and steel production, nonferrous metal smelting, thermal engineering, biochemical engineering, environmental monitoring, medical research and diagnostics, and food preservation. There are many types of special gases, with the main categories including high-purity gases and mixed gases, which can generally be classified into electronic gases, standard gases, environmental gases, welding gases, and sterilization gases, among others.
3. Standard gases are reference materials. Reference materials are highly homogeneous, stable, and accurate measurement standards that play a fundamental role in replication, preservation, and value transfer.
4. Welding protection gases—gases used in gas-shielded welding—have enabled faster economic development for enterprises due to their advantages, including high welding quality, high efficiency, and ease of system automation. The shielding gases can be single-component gases, or they can be binary or ternary mixtures. A typical ternary mixture consists of helium, argon, and carbon dioxide. In practice, the specific composition of the welding gas mixture is selected based on the type of welding material being used.
5. Etching gases are used to remove processed surfaces such as silicon oxide films and metal films. On the substrate surface that is not masked by photoresist, areas covered by photoresist are retained, thereby producing the desired imaging pattern on the substrate surface.
6. A gas with a sterilizing effect is called fumigant vapor. The principle behind sterilization lies in the use of ethylene oxide, which, due to its inert nature, maintains the essential life processes within microbial tissues. Commonly used are mixtures of ethylene oxide and carbon dioxide prepared in various proportions; depending on the ethylene oxide content, these mixtures can be 10%, 20%, 25%, or 30%.
7. During the compression of non-liquefied gases, the gas exists in a physically distinct state within the cylinder, depending on specific ambient pressure and temperature conditions, and exhibits varying boiling points. Based on these differences, we can classify gases into two major categories: liquefied gases and non-liquefied gases.
8. Liquefied gases are gases whose critical temperature is higher than -50℃. They are collectively referred to as either high-pressure liquefied gases or low-pressure liquefied gases. Gases with a critical temperature higher than -50℃ but not exceeding 65℃ are classified as high-pressure liquefied gases, while gases with a critical temperature exceeding 65℃ are classified as low-pressure liquefied gases.
3. Application Fields of Industrial Gases
As an essential foundational raw material for modern industry, industrial gases have a wide range of applications. They are extensively used in sectors such as metallurgy, steelmaking, petroleum, chemical engineering, machinery, electronics, glass, ceramics, building materials, construction, food processing, and healthcare.
1. Metal welding: The gas environment used as an oxidizing agent in metal welding, cutting, and various combustion devices, as well as oxidizing gases employed in certain production process design stages.
2. Mechanical Industry: Metal welding and cutting can significantly improve work efficiency.
3. Chemical Industry: Produces chemical products such as pharmaceuticals, dyes, and explosives; it is also used to increase production efficiency (e.g., oxygen-blown production of yellow phosphorus and oxygen-injection degradation of coal).
4. Electronics Industry: In addition to being used as a combustion gas, it is also employed as an oxidizing gas in the manufacture of semiconductor integrated circuits. High-purity oxygen is also an essential gas source for the production of optical fibers.

5. National defense has many uses: rockets are widely employed.