ASU For Chemical Industry

As the chemical industry's demand for high-purity oxygen, nitrogen, and argon continues to grow, cryogenic Air Separation Units (ASUs) have become essential infrastructure for supporting the continuous operation of large-scale chemical plants. Based on extensive engineering experience, Shenger Gas provides complete ASU for chemical industry systems designed for oxidation processes, ammonia synthesis, inerting, gas protection, and process gas supply. These systems offer stable performance, energy efficiency, and strong adaptability to chemical processing conditions.

Product Overview and Core Principle

An ASU for chemical industry operates on cryogenic distillation. Clean air is cooled to −180°C to −195°C until liquefied and then separated into oxygen and nitrogen within a double-column or triple-column rectification system. A complete ASU typically includes an air compressor, molecular sieve purification unit, plate-fin heat exchanger, expander, distillation column, cold box, and liquid storage tanks.

Process flow summary:

• Air compression: Air is compressed to 0.55–0.75 MPa.
• Purification: Moisture, CO₂, and hydrocarbons are removed by molecular sieve beds to ensure a dew point below −60°C.
• Cryogenic heat exchange: Air is cooled stepwise to liquefaction temperature.
• Fractional distillation: Oxygen, nitrogen, and argon are separated in the low-temperature columns.
• Product output: Gas or liquid products are delivered according to process needs.

Cryogenic separation provides high purity, supports large flow rates, and maintains long-term operational stability, making it the preferred gas supply technology for chemical production facilities.

Key Performance Indicators: Defined by Data

We understand that chemical industry clients focus on measurable performance. Below are the core technical specifications of Shenger Gas ASU systems:

1. Gas Purity and Production Capacity

• Oxygen (O₂):

Purity consistently above 99.6%, with options up to 99.8% depending on process requirements.
Flexible flow-rate design, from several hundred Nm³/h for small installations to tens of thousands Nm³/h for large-scale units-ensuring uninterrupted oxygen supply for oxidation and gasification processes.

• Nitrogen (N₂):

Standard nitrogen purity ≥99.9%, while high-purity nitrogen can reach 99.999%, providing a dry and reliable inert atmosphere for petrochemical facilities.

• Argon (Ar):

Crude argon can be recovered as a by-product and further refined to high-purity argon for specialty welding and advanced fine chemical applications.

2. Operating Conditions and Energy Performance

• Temperature Range:

The core cold box operates reliably at −196°C, with insulation and structural integrity verified through stringent engineering controls to prevent cold losses and energy waste.

• Energy Consumption:

Energy efficiency is a key focus of our technology. Through high-performance molecular sieves, structured packing, and optimized process configuration, our ASU for chemical industry achieves 5%–8% lower specific power consumption compared with industry averages.
A seemingly small percentage gain translates into substantial electricity savings over continuous long-term operation.

System Configuration and Key Components

A cryogenic ASU typically includes:

• Air compression system (main compressor + air treatment)
• Molecular sieve purification system (dual-bed switching, automatic control)
• Aluminum plate-fin heat exchangers
• Expander (air-cooled or oil-film bearing)
• Low-temperature distillation columns (single/double/triple column)
• Cold box with multilayer insulation
• Liquid storage tanks and pump systems
• DCS control system (redundant architecture optional)

All equipment complies with ISO 9001, ISO 14001, ISO 45001, ASME, CE and other international standards.

Application Fit of ASU for Chemical Industry

An ASU for chemical industry is suitable for the following process scenarios:

1. Ammonia Synthesis and Hydrogen-Based Processes

• Nitrogen for ammonia synthesis (N₂ + H₂)
• Oxygen for oxidation in coal-to-chemicals and olefin production

2. Oxidation Reactions and Off-Gas Treatment

• Oxygen for PTA production, ethylene oxide, and formaldehyde oxidation
• High purity and stable flow are critical for oxidation reactions

3. Inerting, Purging, and Protective Atmospheres

• Nitrogen for tank inerting, pipeline purging, and protective gas transport
• Typical nitrogen purity requirement in chemical plants: 99.9%–99.999%

4. Gas-Assisted Separation and Environmental Treatment

• Oxygen enhances combustion efficiency in VOC incineration
• Nitrogen used for pressure conveying and explosion-prevention systems

Control System and Operational Reliability

The reliability of a cryogenic ASU relies on:

• Stable front-end purification (dew point maintained below design value)
• Precise control of tray liquid levels, reflux ratio, and pressure differentials
• Continuous monitoring of heat-exchanger ΔT and expander performance

Well-designed ASUs typically achieve over 8,000 operating hours per year, with major overhauls every 2–3 years.

Why Chemical Plants Choose Cryogenic ASU

Chemical processors adopt cryogenic ASUs for the following reasons:

• Continuous, large-volume gas supply for large-scale units
• High-purity oxygen, nitrogen, and argon production
• Low specific energy consumption and predictable long-term costs
• Full integration with plant-wide DCS systems
• Ability to supply both gaseous and liquid products for peak-shaving needs

For long-running chemical installations, cryogenic ASUs remain the most economical and dependable gas-supply method.

As a supplier of cryogenic technology and industrial gas systems, Shenger Gas provides complete lifecycle support-from process design and equipment manufacturing to system integration and on-site commissioning. We deliver stable, high-purity, energy-optimized ASU for chemical industry solutions to ensure long-term operational reliability for chemical plants.

For technical proposals, energy-consumption evaluations, or customized system configurations, please contact us.

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