NEWTEK Announces Energy-Efficiency Optimization On 45,000 M³/H Air Separation Unit

 

NEWTEK announced the successful implementation of a full-scale energy-efficiency optimization program on a 45,000 m³/h Air Separation Unit (ASU), achieving measurable reductions in steam consumption, compressor load and overall system energy demand. The project aligns with the 's strategic roadmap of enhancing process efficiency and supporting low-carbon development across industrial gas operations.

This optimization was carried out on an ASU employing molecular-sieve warm-box purification, turboexpander refrigeration, double-column rectification and internal liquid oxygen/nitrogen pump compression. The initiative focused on matching compressor load with actual oxygen and nitrogen demand and reducing energy consumption of compression systems, which historically account for more than 90% of total ASU power and steam usage.

 

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Background and Energy Profile

The 45,000 m³/h ASU operates with a turbine-driven "one-to-two" configuration, where a steam turbine drives both the main air compressor (MAC) and booster air compressor (BAC).
Design parameters included:

 

●MAC shaft power: 21,100 kW

●BAC shaft power: 18,200 kW

●High-pressure steam requirement: 167.4 t/h (design), with extraction steam at 30 t/h

●Total ASU energy consumption: approx. 41,119 kW before optimization

●Compressor system share of total energy: ~96%
 

Under actual plant demand, the ASU operated at ~80% oxygen load, yet the steam turbine consumed ~97% of the design steam flow, resulting in an energy mismatch and elevated operating costs. This mismatch became the core target of NEWTEK's optimization initiative.

 

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Optimization Measures Implemented by NEWTEK Engineering Team

●Turboexpander Performance Improvement

Modified anti-surge curve to eliminate unnecessary recycle flow.

Closed expander recycle valve and increased inlet guide vane opening to raise expander speed.

Increased available refrigeration, allowing reduction of booster compressor discharge pressure and lowering steam demand.

●Heat-Exchanger Cleaning and Cooling Improvement

Addressed fouling in circulating-water coolers that affected expander cooling efficiency.

Added DN80 valve for weekly online backflushing to restore heat-transfer performance.

Achieved 4–5 K reduction in booster-inlet temperature, improving expander refrigeration margin.

●MAC/BAC Load Matching and Surge-Margin Control

Reduced MAC inlet flow by lowering compressor speed and adjusting inlet guide vanes.

Ensured air-filter PLC stability and performed regular filter maintenance to maintain low inlet resistance and stable suction pressure.

Reduced BAC second- and third-stage pressures and narrowed anti-surge valve openings to ~5% while maintaining required surge margin.

●Rectification Column Optimization

Adjusted reflux conditions to maintain impurity-nitrogen O₂ volume fraction at 2–4%.

Increased pure liquid-nitrogen throttling to raise oxygen recovery in the lower column.

Reduced compressor load by improving rectification efficiency and stabilizing column pressures.

●Molecular-Sieve Adsorber Cycle Optimization

Extended pressurization period from 22 min to 25 min to reduce fluctuations in cold-box inlet flow.

Improved stability during adsorber switchover, reducing frequent adjustments to MAC inlet guide vanes.

Extended adsorption cycle from 4 h to 6 h, lowering regeneration steam consumption.

 

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Measured Outcomes

 

Following one full year of optimized operation, the ASU demonstrated stable performance and significant energy reductions. Key results include:

 

●High-pressure steam consumption reduced from 134 t/h to 124 t/h

●Lower MAC discharge pressure (0.497 MPa → 0.489 MPa)

●Reduced BAC second- and third-stage pressures

●Elimination of expander recycle flow (14% → 0%)

●Increased expander guide-vane opening and improved refrigeration availability

 

With an average reduction of 10 t/h high-pressure steam, the ASU saves approximately 72,000 t of steam annually (based on 8,000 operating hours).
 

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Strategic Significance for NEWTEK

The optimization project reflects NEWTEK 's commitment to:

●Enhancing energy performance across industrial-gas and cryogenic-equipment assets

●Supporting low-carbon transformation through systematic efficiency improvements

●Strengthening engineering service capabilities across air-separation, hydrogen, synthesis-gas and environmental-protection systems

●Delivering measurable efficiency gains for downstream users in chemicals, energy, and advanced materials

●By integrating engineering enhancements, digital operation insights, and long-term reliability management, NEWTEK continues to ●expand its portfolio of efficient gas-production solutions across global markets