Air Separation System

Operating Principle

The air separation system operates by extracting liquid nitrogen from the air using an ultra-freezing method. This involves cooling the air to a liquid state, facilitated by a low-pressure expansion turbine. The key principle is to take advantage of the different boiling points of liquid oxygen and nitrogen. In this way, the air is separated in a fractionation column, producing liquid nitrogen with an exceptional purity of over 99.99%.

Process Description

The air separation process begins with the intake of air through a filter, followed by compression in an air compressor until it reaches a pressure of 0.8 MPa. After compression, the air is cooled and sent to a purifier where impurities such as water, carbon dioxide, and acetylene are removed. The purified air passes through a heat exchanger, where it exchanges heat with the returned oxygen.

From this point, part of the air is directed to an expansion turbine, where its expansion generates the necessary cooling for the system. The remaining air passes through a second heat exchanger before entering the rectification column. In this column, the air is separated into its components: oxygen and nitrogen. High-purity liquid oxygen is collected from the top of the column, while the liquid air at the bottom is decompressed through a throttling valve and undergoes further processing in an evaporator condenser. This process ensures that the air is adequately cooled while passing through various heat exchangers, acting as a regenerative purifier.

Equipment Advantages

Integrated Structure: The system is designed with a direct skid-mounted structure, using high-pressure hoses, eliminating the need for additional piping and valves, thus reducing costs.
Simplified Installation: The equipment requires only a prepared space with basic lifting tools. No additional materials or tools are needed for installation.
Compact Design: The equipment is compact, occupies little space, and does not require a foundation, facilitating operation and maintenance.
Efficiency: The system incorporates advanced technology to reduce energy consumption and minimize electricity costs. The internal compression process also reduces maintenance costs and improves overall efficiency.
Air Cooling System: The cooling mechanism is air-cooled, eliminating the need to build cooling ponds, further reducing capital costs.

Instructions for Support Units

1. Air Compressor (1 unit)

The air compressor features a screw-type mechanism within a closed structure. It integrates lubrication, electricity, cooling, and instrument control, forming a fully automated and low-noise system. The intelligent PLC controller with a touch panel allows parameter adjustments and monitoring, with support for display in English and Spanish. The system includes automatic protection, alarms, remote control, and tracking history, enabling unattended operation.

Manufacturer: AEUT-AP or equivalent
Type: Screw with oil injection (oil content ≤3ppm)
Model: AED110A/10
Flow Rate: 24.2 m³/min (1200 Nm³/h)
Inlet Pressure: 0.092 MPa
Inlet Temperature: 25°C
Relative Humidity: 82%
Outlet Pressure: 8 bar
Outlet Temperature: 40°C
Motor Power: 110 kW
Cooling Method: Air cooling

2. Pre-Cooling System (1 unit)

This system uses a fully enclosed compressor to prevent refrigerant leakage, along with a vapor separator and automatic drain to ensure that the air remains dry. With high-quality imported components, the system provides long-term continuous operation. It features remote signal interfaces for inlet and outlet air temperatures, as well as start/stop controls and failure signals.

Model: SAYL-1200/10
Processed Air Capacity: 1200 m³/h
Inlet Pressure: 1.0 MPa
Inlet Temperature: ≤45°C
Outlet Temperature: 5-8°C
Power: 20 kW
Cooling Method: Air cooling

3. Purification System with Molecular Sieve (1 unit)

This system features a dual adsorption cylinder structure, allowing one cylinder to operate while the other regenerates, ensuring constant air purity in the column and prolonging the operation of the fractionator. It has automatic temperature control for the regeneration process.

Model: HXK-1200/7.5
Capacity: 1200 Nm³/h
Adsorbent: Molecular sieves 13X
Design Pressure: 10 bar
Inlet Temperature: 8°C
Outlet Temperature: 12°C
Regeneration Temperature: 180°C

4. Expansion Turbine (1 unit)

Developed by the Institute of Physics and Chemistry of the Chinese Academy of Sciences, this expansion turbine offers high efficiency, vortex resistance, and low cold loss.