Cryogenic Nitrogen Plant, Its Applications, Advantages and Salient Features

SK Agarwal
5 min readJun 28, 2023

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Liquid Nitrogen Production System

Cryogenic nitrogen plant is advanced industrial machinery that uses cryogenic distillation technique for separating nitrogen from atmospheric air. With the help of cryogenic temperature and high pressure processes, the cryogenic based plants liquefy and extract nitrogen molecules generating high purity N2 gas. However, the purpose of the cryogenic machinery is multi-faceted with applications in diverse range of industries. Mostly, they cater to the requirements of sectors such as food preservation, chemical manufacturing, aerospace and electronics. Additionally, the cryogenic plants also offer uninterrupted supply of N2 gas for blanketing, purging, and inerting processes while maintaining product quality and safety. From preventing oxidation in sensitive electronic components to preserving food freshness, cryogenic nitrogen plants play a pivotal role in meeting industrial demands while contributing to technological advancements and product preservation.

Overview of importance of cryogenic nitrogen plants in various industries

As mentioned above, cryogenic air separation facilities are very important for numerous industries. Undoubtedly, they are the trusted source of generating high purity nitrogen for use in various applications. Moreover, cryogenic distillation is the only technology with capacity to generate N2 with purity up to 99.99%. Besides, their manufacturing is completed with ASME certified materials that can withstand cryogenic temperature and extremely high pressure. And, air separation column being the heart of the machinery, their manufacturing is accomplished with 100% cryogenic grade stainless steel with argon welding. Most of the leading nitrogen plant manufacturers offer N2 producing machines with quality standards assured by leading quality assurance companies ISO 9001:2015 and CE.

Numerous applications of nitrogen include cooling during manufacturing processes, stopping oxidation, soldering, etc. Further, food industry uses cryogenic nitrogen for packaging, preserving and freezing food products. Chemical manufacturing is also dependent on nitrogen for blanketing, purging and inerting for stopping reactions and maintaining safety. In aviation and aerospace, cryogenic nitrogen is used for fuel storage, fire suppression and pressurization systems. Moreover, there are extensive applications of cryogenic or liquid nitrogen (LN2) in numerous industries as well such as pharmaceuticals, healthcare, metal fabrication, and research laboratories.

Working Principles of Cryogenic Nitrogen Plants

It is important to remember that working principles LN2 plants are dependent on cryogenic distillation and air separation techniques. Initially, atmospheric air is compressed to increase pressure. Thereafter, it goes through cooling process using heat exchangers achieving liquefaction at very low temperatures. The liquefied air is directed into distillation columns separating it into nitrogen, oxygen and other gases on the basis of their different boiling points.

However, nitrogen is very less volatile so accumulates at the top of the column. It is collected as the desired product and is distilled in the low pressure distillation column to achieve commercially specified purity. Meanwhile, oxygen and other gases are eliminated back into the atmosphere. The collected nitrogen is purified and compressed for storage. However, there is option for customizing purity as per requirements of different industries.

Brief description of cryogenic distillation process

Cryogenic distillation is the most efficient process for air separation. It achieves air separation of gases based on their boiling points.

Important features of cryogenic distillation

· At extremely low temperatures, gases are condensed into liquids, making them easier to separate.

· The process begins with a feed mixture of different gases, such as oxygen, nitrogen, and argon.

· The mixture is compressed and cooled to temperatures below their boiling points.

· Through fractional distillation, the liquid mixture is introduced into a distillation column.

· Inside the column, the liquids vaporize and rise, while the heavier components sink.

· As the temperature increases from bottom to top, the different gases condense at their respective boiling points.

· The condensed gases are collected and further processed for purity.

· This technique is crucial for producing high-purity gases used in various industries, including healthcare and manufacturing.

· Cryogenic distillation is a precise and efficient method, enabling the extraction of valuable gases with minimal energy consumption.

· Understanding the cryogenic distillation process empowers us to appreciate the remarkable advancements in gas separation technology.

Role of air separation units (ASUs) in separating oxygen from air

Air separation units (ASUs) are important for their crucial role in separating nitrogen from air. The units are designed to extract nitrogen with a highly efficient process. Using advanced technologies, ASUs leverage the differences in boiling points and molecular weights to separate the components of air. After being cooled and compressed, the air undergoes liquefaction allowing for the separation of nitrogen. ASUs generate reliable and uninterrupted supply of high purity nitrogen. Moreover, the units are vital in numerous industries for purging, inerting and preventing oxidation. Undoubtedly, they are essential tools for producing nitrogen for meeting ever increasing demand.

Liquefaction and storage of nitrogen in short

· Nitrogen liquefaction is achieved through cryogenic distillation process

· It involves subjecting nitrogen to extreme cold temperatures, reaching as low as -196 degrees Celsius.

· Liquefied nitrogen has azure color

· The process of liquefaction allows nitrogen to be stored in a more compact and manageable form.

· Liquid nitrogen possesses useful properties, such as its ability to rapidly freeze and preserve perishable substances.

· Cryogenic containers, designed to withstand extreme temperatures, provide a safe and secure environment for storing liquid nitrogen.

· These containers act as vital reservoirs, serving a wide range of industries, from food preservation to medical applications.

· Liquefied nitrogen finds extensive use in scientific research, enabling breakthroughs in fields like cryogenics, superconductivity, and material science.

· The storage of nitrogen in liquid form offers enhanced flexibility and accessibility for various industrial processes.

· Liquefaction and storage of nitrogen play important role in innovation and endless possibilities.

Advantages of Cryogenic Oxygen Plants

· High purity nitrogen production

· Cost-effectiveness compared to other oxygen production methods

· Reliability and scalability

· Continuous production capabilities

· Flexibility in meeting different oxygen demands

Overview of key components

Nitrogen gas plants are indispensable for generating high purity nitrogen. Most important components of the plants are air compressors, heat exchangers, and distillation columns. Air compressors are essential for pressurizing the air which creates conditions for achieving air separation. Heat exchangers are crucial for creating efficient cooling and attaining liquefaction of the air stream. And, distillation columns are responsible for facilitating air separation on the basis of different boiling points of the gases. Together, the three components are necessary for getting the desired purity levels and production rates. The interaction between compressors, heat exchangers, and distillation columns makes them the backbone of cryogenic air separation process.

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SK Agarwal

Technical Director@UNIVERSALBOSCHI, Masters in Mechanical Engineering (BITS), Specialization in designing, manufacturing Oxygen Nitrogen Air Separation Plants.