The main advantage of cryogenic air separation units is their ability to produce air separation products in virtually any volumes and with various purity levels. Only cryogenic units make it possible to obtain several products simultaneously, as well as to produce them in liquid form. Unlike adsorption and membrane technologies, increasing product purity in cryogenic units has little effect on the recovery rate and the cost of the equipment.

The disadvantages of cryogenic units include a long start-up period associated with cooling the equipment down to cryogenic temperatures, which takes from 8 to 24 hours. Such units are ideally suited for plants with high nitrogen demand.

Principle of operation

Cryogenic air separation units are designed to produce concentrated nitrogen by separating liquefied air into its components using the method of fractional distillation. The air is first compressed, purified from impurities, and cooled to a liquefied state at a temperature of about -183°C. The liquefied air is then fed into a distillation column, where, due to differences in the boiling points of the components, they are separated: nitrogen (boiling point -196°C) is withdrawn from the top of the column, and oxygen (boiling point -183°C) from the bottom. This provides the production of high-purity nitrogen.

The nitrogen production automation unit is equipped with systems for monitoring and controlling process operations, which improves both efficiency and operational safety.
Standard equipment package of cryogenic nitrogen plants:

• Expander-compressors
• Refrigeration units;
• Pumps;
• Electrical cabinets and control systems;
• Separation unit;
• Cryogenic storage tanks;
• Vaporizers;
• Purification unit;
• Scrubbers;
• Storage and gasification systems;
• Other auxiliary equipment

Thanks to the sophisticated process flow scheme, the resulting product has an impurity content close to zero.
Key characteristics include: purity of liquid and gaseous nitrogen, plant capacity, pressure, required installation area, electrical requirements, and ambient temperature conditions.

All valves of all systems and units are supplied as a complete set, including matching flanges, seals, and connecting elements. Within the scope of supply, carbon steel pipelines will be sandblasted, cleaned, primed, and hermetically packed.

Pipelines and equipment operated in an oxygen environment, as well as all cryogenic vessels, valves, and piping, will be supplied degreased, dehydrated, and hermetically sealed. Cryogenic pipelines with screen-vacuum insulation are intended for connection to the storage system for liquid air separation products.

The adopted process flow and design solutions, combined with the automated monitoring and control system, ensure high efficiency of the technological processes, ease of operation, and the ability to smoothly adjust the plant capacity for the air separation products.

Functions of the automated control system

• Automatic switchover of adsorbers in the air comprehensive purification unit;
• Measurement and control of the plant’s process parameters, and pre-alarm and emergency (visual and audible) signalling when these parameters deviate from normal values;
• Stabilization of the main parameters by means of automatic control loops;
• Remote control of the unit’s actuated valves and plant equipment;
• Automatic emergency shutdown protection (ESD) of the process equipment;
• Automatic interlocks preventing the occurrence of emergency situations and erroneous personnel actions;
• Protection of turboexpander-compressor units against exceeding the maximum permissible rotational speed and vibration levels;
• Information exchange (the scope of information is to be specified at the detailed design stage) with the air compressor control system;
• Monitoring and control of the storage and gasification system and plant equipment as specified by the design organization;
• Transmission of information to systems developed using software and hardware means.

Areas of application

A nitrogen production plant is in demand for solving important production and economic tasks in various sectors:

• Metallurgy – heat treatment, metal cutting, alloy nitriding;
• Chemical and pharmaceutical industry – production of ammonia, fertilizers, dyes, explosives, pharmaceuticals;
• Food industry – packaging of products to prevent spoilage and oxidation;
• Medicine – cryotherapy and other medical procedures;
• Energy sector – creation of an inert atmosphere in gas turbines;
• Oil and gas production – well drilling, enhanced oil recovery;
• Manufacture of refrigeration equipment;
• Conducting scientific research.

Purchase of a cryogenic nitrogen plant

RusGazCryo LLC represents on the Russian market the cryogenic equipment of the Chinese manufacturer Hangzhou Oxygen Plant Group. The required equipment package can be purchased by submitting a request on the company’s website. The order price is determined taking into account the project specifics and the conditions of the particular production facility.

For automation of monitoring and control, an automatic system based on specially developed software is implemented. On request, we perform project calculations, provide commercial and technical proposals, and also take part in tenders.

The supplied products undergo mandatory acceptance testing and are delivered to the operating site with a complete set of documentation.

RusGazCryo LLC offers safe and reliable automated solutions for a wide range of industrial tasks. Our company will design the project, manufacture the equipment, perform its installation and commissioning, provide personnel training, and ensure subsequent after-sales service.