Cryogenic Air Separation Units

Atmospheric air contains approximately 78% nitrogen, 21% oxygen, and the remaining share is made up of carbon dioxide, noble gases, methane, nitrous oxide and ozone. In air separation units, products of low-temperature rectification are obtained from air.

Classification of air separation units

• By cycle pressure, kgf/cm^²:
  • High (150–200)
  • Medium (40–70)
  • Low (5–12)
• By the method of fraction separation:
  • Adsorption
  • Membrane
  • Cryogenic

GOST R 54892-2012 applies to air separation units and to all types of cryogenic systems installed at various production sites and air separation stations. This regulatory document serves as the basis for the construction, modernization and repair of cryogenic facilities and equipment.

Classification

Cryogenic air separation units can be classified:

• By capacity of the main product:
  • For oxygen
  • For nitrogen
  • For argon
  • For rare gases
• By type of end product:
  • Oxygen units
  • Nitrogen units
  • Nitrogen-oxygen units
  • For argon production
  • For rare gas production
• By process scheme:
  • By refrigeration cycle
  • By purification and drying method
  • By rectification arrangements
• By mobility:
  • Mobile
  • Stationary

Principle of operation

The operation of an air separation unit consists of the following stages:

• A compressor unit compresses the air to the specified working pressure;
• An integrated purification and drying unit removes moisture, carbon dioxide and hydrocarbons from the air using adsorbents (synthetic NaX zeolite);
• A turboexpander unit and heat-exchange system prepare the bottom liquid to be fed to the rectification column;
• The rectification column separates pure nitrogen from the bottom liquid;
• When the cryogenic equipment is used for oxygen production, the bottom liquid is directed to the lower column, where liquid oxygen is recovered and then withdrawn from the system through a condenser–evaporator.

Purchase of cryogenic oxygen units

RusGazKrio supplies all types of air separation units in Moscow, across Russia and the CIS. The continuous process cycle is at least one year, with capacities up to 110,000 Nm³/h.

The standard scope of supply includes:

• Compressor and turboexpander units;
• Integrated air purification and drying unit;
• Cooling system;
• Separation block;
• Control, power supply and gasification systems;
• Storage tanks;
• Documentation.

Air separation units based on low-temperature rectification are supplied with an air turbo compressor. The exact scope of supply depends on the customer’s request and is reflected in the final price of the air separation unit.

Key features of the supplied units

• The air pre-purification unit performs adsorption using layers of alumina and zeolite;
• Use of high-efficiency plate-fin heat exchangers;
• Use of a turboexpander–compressor makes it possible to reduce operating costs: cooling is achieved by air expansion in the turboexpander, while cycle pressure is increased by compression in the compressor;
• Equipped with a monitoring and control system based on personal computers operating in interactive (dialog) mode.

About the Company

RusGazKrio LLC offers supply and installation of air separation units (cryogenic and adsorption types) at manufacturer prices. Each unit is designed to meet the specific tasks and requirements of the customer. Our scope of services includes:

• Design;
• Manufacturing;
• Supply of air separation equipment;
• Supervision of installation and commissioning;
• Maintenance during operation;
• Personnel training.

Our specialists adapt air separation units to the conditions of a specific production facility. To ensure uninterrupted commissioning, our qualified engineers carry out preparatory work for two to three months.

Technical characteristics of oxygen air separation units

• Capacity: 10,000–120,000 Nm³/h;
• Products: O_₂, N_₂, Ar, Ne, Xe, Kr.
• Product purity:
• Nitrogen: 99.9995 … 99.9999 vol.%
• Oxygen: 99.5 … 99.9 vol.%
• Argon: 99.9995 vol.%

The separation systems we offer are characterized by high efficiency, reliability, a high degree of automation, and long-term, straightforward operation.

Production

Air separation equipment is manufactured by Hangzhou Oxygen Plant Group (China), which is one of the global leaders in the production of cryogenic and compressor equipment. At the customer’s request, we can arrange visits to the foreign manufacturing site.

RusGazKrio has been cooperating with its Chinese partners for more than fifteen years.

Automatic control systems

The division responsible for automated control systems is located on a 600 m² production site in Krasnodar. The equipment is manufactured either according to the customer’s design documentation or based on designs developed by our own engineering department. Quality is monitored at all stages of production, and all products are certified.

Information about RusGazKrio is published on the Siemens website as a holder of partnership certificates, which confirms both the use of Siemens technologies and the compliance of our employees’ competencies with the standards of the Siemens Group.

Our automation projects have been implemented at around thirty major enterprises in the oil and gas, power and metallurgical industries. Examples:

• Production site and component warehouse with an area of 600 m²;
• Certified Siemens System Integrator;
• More than 30 large-scale automation projects completed.