Product Overview
Liquid nitrogen (LN₂), a hazardous cryogenic chemical with CAS number 7727-37-9, is a colorless, odorless, non-flammable liquid derived from fractional distillation of air. It is widely used in various industries but requires careful handling due to its ultra-low temperature and asphyxiation risk, making it a regulated hazardous substance.
Basic Information
| CAS No. | 7727-37-9 |
| UN No. | UN 1977 (Nitrogen, refrigerated liquid) |
Key Attributes & Parameters
| Purity | Typically ≥ 99.5% (industrial grade), with high-purity grades (e.g., 99.999%) available for sensitive applications. |
| Boiling Point | -195.8 °C (-320.4 °F) at atmospheric pressure. |
| Density | ~0.808 g/mL at its boiling point. |
| Appearance | Colorless, clear cryogenic liquid; may appear to "boil" or produce fog when exposed to ambient air. |
| Expansion Ratio | 1 volume of liquid expands to approximately 696 volumes of gas at 21°C. |
Features & Advantages
Extremely Low Temperature
Provides rapid, deep cooling for freezing, preservation, and thermal contraction applications.
Chemically Inert
Creates safe, oxygen-deficient atmospheres for blanketing, purging, and preventing oxidation or combustion.
High Availability & Cost-Effectiveness
As the primary component of air, it is abundant and typically the most economical cryogen.
Dual-Phase Utility
Can be used directly as a liquid for its cooling power or easily vaporized to produce a large volume of dry, inert gas.
Functional Characteristics
Features: Ultra-low boiling point (-196°C), inert chemical property (stable except at high temperatures), non-corrosive, fast vaporization, and high cooling capacity. Material: Stored and transported in double-layer vacuum-insulated containers, inner tank made of stainless steel (anti-corrosion) and outer tank of carbon steel (anti-impact) to reduce evaporation loss.
Advantages
1. High purity: Meets industrial and laboratory requirements, with minimal impurities (O₂≤0.5ppm, H₂O≤3ppm). 2. Efficient cooling: Rapidly lowers temperature, ideal for freezing, cryopreservation and low-temperature processing. 3. Safe storage: Special vacuum-insulated containers reduce daily evaporation loss to ≤2%. 4. Versatile: Suitable for food, medical, industrial and research fields.
Primary Application Fields
Food & Beverage
Quick freezing of food products (IQF), cryogenic grinding of spices, and inerting in packaging to extend shelf life.
Healthcare & Biotechnology
Long-term preservation of biological samples (sperm, eggs, tissues), blood, and vaccines in cryogenic storage; cryosurgery for removing abnormal tissues.
Metalworking & Manufacturing
Shrink-fitting metal components, cryogenic treatment of metals to enhance wear resistance, and providing inert atmospheres for welding and heat-treating.
Electronics & Chemicals
Cooling during semiconductor manufacturing, inerting chemical reactors, and pulverizing materials.
Research & Laboratories
Providing cryogenic temperatures for scientific experiments, vacuum trap cooling, and instrument cooling (e.g., in electron microscopes and spectrometers).
Customer Collaboration Case
We partnered with a national biobank to design and supply a complete, large-scale liquid nitrogen management system for their facility. The challenge was to ensure a continuous, fail-safe supply of liquid nitrogen for thousands of cryogenic storage tanks containing irreplaceable biological specimens. Our solution included the installation of a bulk storage tank with automated monitoring, a vaporization system for facility inerting, and a networked, point-of-use filling system for the storage Dewars. We also provided 24/7 remote monitoring and a guaranteed backup delivery schedule. This integrated system eliminated supply risks, optimized operational costs, and provided the biobank with the reliability required for their critical mission of preserving genomic and tissue samples for future research.
FAQ
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