Comparison of Carbon Dioxide and Liquid Oxygen Storage Tanks

 
Carbon dioxide (CO2) storage tanks and liquid oxygen (LOX) storage tanks are essential in industrial production and gas storage, differing in physical properties, design structure, and applications. Although both storage tanks use advanced insulation technology, the distinct characteristics of the stored media result in significant differences in design, material selection, and operational requirements.

Temperature and Material Differences

 
The storage temperatures for CO2 and liquid oxygen vary greatly. CO2 is typically stored at around -20°C, whereas liquid oxygen requires storage at an extremely low temperature of -186°C. Such low temperatures place high demands on the cryogenic performance of materials. The inner tank of a LOX storage system must be constructed from materials that retain high strength and toughness at cryogenic temperatures, commonly using high-quality alloys such as stainless steel. In contrast, CO2 tanks have less stringent material requirements, as they do not need to withstand such extreme cold. Nevertheless, both types of tanks employ efficient insulation techniques, often using polyurethane (PU) or double-layer vacuum insulation to minimize the impact of external temperature changes, ensuring the long-term stable storage of CO2 and LOX.

Pressure and Design Requirements

 
In addition to temperature differences, CO2 and LOX storage pressures also vary. CO2 storage tanks are designed to handle pressures typically between 2.0 and 2.5 MPa, with an operational pressure no lower than 1.4 MPa to prevent CO2 from solidifying into dry ice. If dry ice forms, the liquid CO2 will solidify into a material that is difficult to manage, disrupting normal storage and usage.
 
On the other hand, LOX storage tanks operate at a lower design pressure, usually ranging from 0.8 to 1.6 MPa. Liquid oxygen’s stability at extremely low temperatures reduces the need for high pressure. However, LOX tanks still require excellent sealing and safety measures to prevent leaks, as liquid oxygen is a strong oxidizer and can cause violent reactions when in contact with flammable materials. Therefore, LOX storage tanks must adhere to strict safety standards.

Structure and Insulation Performance

 
Both CO2 and LOX storage tanks use advanced double-layer vacuum insulation to ensure the long-term storage of liquefied gases. CO2 tanks are filled with perlite between the inner and outer layers, which enhances thermal insulation. Under vacuum conditions, perlite further improves insulation by reducing heat transfer and stabilizing the internal pressure, ensuring that external temperature fluctuations do not affect the stored liquid CO2.
 
LOX storage tanks, on the other hand, use double-layer vacuum powder insulation. The inner tank is usually made of stainless steel, while the outer tank is fabricated from materials like Q235B or 16MnR. To protect against corrosion, the outer surface of LOX tanks undergoes processes like sandblasting, cleaning, and coating, which not only extend the tank’s service life but also improve reliability in harsh environments.

Characteristics and Applications of CO2 Storage Tanks

 
CO2 storage tanks are high-pressure, low-temperature vessels specifically designed to store liquid CO2. Their structure is similar to household thermos flasks, consisting of inner and outer layers with vacuum insulation to maintain stable internal temperatures and appropriate pressure conditions. This design ensures the liquid CO2 remains in the desired state, preventing it from vaporizing or solidifying, thus ensuring safe and long-term storage.
 
CO2 storage tanks come in both vertical and horizontal designs, allowing users to select the appropriate type based on available space. Since CO2 must remain in a liquid state under high pressure, the tank’s capacity is closely related to its vacuum level. Typically, for tanks with a volume of 10 cubic meters or less, the vacuum level should be maintained below 2 Pa to ensure adequate insulation.
 
These tanks are widely used in industries such as food and beverage, chemical manufacturing, and cold chain logistics, serving as efficient storage systems for low-temperature refrigerants. CO2’s excellent cooling properties make it ideal for industrial cooling, ultra-low temperature experimental equipment, and other applications requiring cold environments.

Characteristics and Applications of Liquid Oxygen Storage Tanks

 
LOX storage tanks are primarily used for storing liquid oxygen, nitrogen, argon, and CO2. Unlike traditional high-pressure cylinders, LOX tanks can store large volumes of liquefied gas. One cubic meter of liquid oxygen can replace around 130 gas cylinders, significantly reducing the frequency of cylinder transportation and replacement, saving both labor and resources.
 
LOX tanks are widely utilized in industries requiring large quantities of gas, such as gas supply, hospitals, metal smelting, and manufacturing. They can supply high-purity gas to steel plants, gas production facilities, food and beverage processing, welding, and medical industries. LOX storage tanks not only lower gas costs but also greatly enhance safety by reducing the risks associated with high-pressure gas cylinders.
 
The design features of LOX storage tanks make them suitable for centralized gas supply systems. These tanks offer long service life, compact structure, small footprint, and convenient operation. The combination of their double-layer structure and advanced anti-corrosion technology enables them to operate reliably in various harsh environments, making them the preferred choice for liquid storage in many industries.

Maintenance and Safety

 
For both CO2 and LOX storage tanks, good insulation and regular maintenance are essential to ensure safe operation. Since the liquefied gases are highly sensitive to temperature and pressure changes, any failure in the insulation system could cause the liquid to vaporize, increasing internal pressure and potentially leading to dangerous situations. Therefore, routine checks on the sealing and vacuum levels of the insulation are critical.

Conclusion

In conclusion, while CO2 and LOX storage tanks differ in terms of design, temperature, and pressure, both ensure the safe storage of low-temperature liquefied gases through efficient insulation technologies. CO2 tanks, with their high-pressure design and excellent refrigeration performance, are widely used in cooling and cold chain industries. Meanwhile, LOX tanks provide an efficient, economical, and safe solution for supplying high-purity gases in various sectors.