China Coal Yulin 85,000 Nm³/h (O₂) Air Separation Project

Typical Customer Case — China Coal Yulin 85,000 Nm³/h (O₂) Air Separation Project: Domestic First Demonstration of 40 MW Class Ultra-High-Power Electric Drive

Project Overview

The domestically manufactured first-of-a-kind 85,000 Nm³/h (O₂) air separation unit (ASU) rolled off the production line and was deployed at the China Coal Yulin coal deep-processing base. The ASU is driven by a domestically produced ≈40 MW class ultra-high-power electric drive system, marking the first demonstration of such large electric-drive equipment in China’s coal-chemical sector. The unit has been officially included in a national demonstration program and, together with the Shenhua Baotou 2×105,000 Nm³/h ASU project, represents an important engineering model for promoting electrification, high-power domestic solutions, and the national “dual-carbon” objectives.

Background & Business Value

Air separation units are critical infrastructure for coal-to-chemical, syngas and downstream chemical processes. Large-scale oxygen supply is essential for process stability and economics.

Traditionally, large ASU compressors are driven by gas turbines or imported electric drives, which involve high costs, long lead times and low domestic content. This project achieves localization of the key equipment—domestically producing a 40 MW class ultra-high-power motor and electric drive system—thereby significantly improving supply-chain controllability, shortening delivery time, and reducing total cost of ownership (TCO).

The project serves as a demonstration of replacing fossil-fuel driven compressors with electric drives (“electric substitution”), facilitating integration of renewable power, reducing carbon emissions, and supporting national carbon-reduction goals.

Technical Solution & Core Features

To meet the large-flow O₂ ASU requirements for stable supply and high reliability, the technical solution is designed holistically across motor, drive, drivetrain and control:

• Ultra-high-power motor (~40 MW): Designed for the high-torque and continuous long-duration operation of ASU compressors. Typical design features include high power density, reinforced mechanical strength and advanced thermal management — e.g., large-section conductors, optimized slot geometry, low-loss electrical steel, and Class F insulation assessed by Class B temperature rise.

• Electric drive & VSD (variable-speed drive): High-power converters (PCS / VSD) provide soft start, closed-loop torque control and optimized energy management. Wide-range speed control matches compressor conditions and can support energy recovery if the system permits.

• Cooling & thermal management: To handle very high heat flux, motors and converters typically use water cooling or hybrid water-air cooling with redundant circuits and online temperature/flow monitoring and protective interlocks.

• Drivetrain & coupling options: Direct coupling (no intermediate gearbox) or short-span gearbox / hydrodynamic coupling solutions are used, prioritizing high efficiency and low loss while addressing vibration, axial loads and maintenance convenience.

• Smart monitoring & plant integration: Full online condition monitoring (windings/bearing temperatures, vibration, speed, cooling flow and temperature, excitation/DC bus parameters, etc.) integrated with DCS/SCADA for data acquisition, alarms and predictive maintenance (CBM).

Typical Technical Parameters (Illustrative)

• ASU capacity: 85,000 Nm³/h (O₂)

• Drive motor rated power: ≈40 MW (single unit or parallel units depending on compressor arrangement)

• Motor type: Large-power, low-speed synchronous/asynchronous motor (configured per project)

• Cooling: Water cooling / water-air hybrid (redundant circuits)

• Insulation class: F (evaluated per B-class temperature rise)

• Operation mode: S1 continuous duty; VSD/soft-start capability

• Online monitoring: Winding/bearing temperature, vibration, speed, cooling flow/temperature, excitation/DC bus parameters

Manufacturing & Test Verification

• Materials & supply-chain control: Key components (silicon steel sheets, large-section copper bars, bearings, insulation, cooling loop components) are subject to strict supplier qualification, incoming inspection and traceability management.

• Process control: Stator winding VPI, high-precision rotor assembly, rotor dynamic balancing, and multi-channel temperature/vibration sensor installation are executed under controlled procedures.

• Factory acceptance tests (FAT): No-load/load testing, temperature-rise tests, dynamic balance and vibration monitoring, VSD/soft-start integration trials, cooling-loop integrity and redundancy switching tests.

• Third-party & demonstration acceptance: As a national demonstration task, tests and data are typically witnessed by the client and third-party organizations; reports are archived as demonstration documentation.

Installation & Commissioning Focus

• Foundations must be designed for high dynamic loads and vibration and validated by modal analysis.

• Precision alignment, coupling commissioning and proper arrangement of lubrication systems are critical for long-term stability.

• Drive-compressor matching and tuning: verify VSD control strategies, torque curves and compressor behavior.

• Implement prolonged loaded run-in tests and collect temperature, vibration and energy consumption data to optimize protection thresholds and maintenance plans.

Operational Results & Demonstration Value

• Localization success: The domestic 40 MW electric drive system replaces imported units, substantially reducing lead time and procurement cost while improving supply-chain autonomy.

• Operational stability: Equipment meets the continuous operational reliability requirements for large-flow ASU, with temperature rise, vibration and other key indicators stable and controllable.

• Energy efficiency & carbon reduction: VSD-enabled electric drives deliver superior energy performance under variable operating conditions; combined with cleaner grid power, the solution supports lower process carbon emissions and contributes to national carbon goals.

• Scaling & industrial impact: Inclusion in the national demonstration program amplifies the project’s influence and will accelerate domestic capability upgrades across motors, converters, cooling and monitoring sub-systems.

Engineering Challenges & Mitigation Strategies

• Thermal management & thermal stress: High heat density is addressed via CFD-optimized cooling circuits, composite water-cooling approaches and redundant coolant loops.

• Starting current & grid impact: Large VSDs and soft/controlled ramp start strategies are used; where necessary, grid-side reactors or energy buffering devices may be added to limit perturbation to the grid.

• Reliability & maintenance accessibility: Modular design of critical components, local spare stock, and rapid response maintenance teams improve uptime and serviceability.

• Demonstration & compliance: Strict third-party witnessing, data reporting and adherence to national demonstration requirements ensure transparency and replicability.

Contribution to “Dual-Carbon” Strategy & Industrial Upgrade

• Promoting electrification: Replacing gas/fuel-driven compressors with electric drives enables reductions in process-end carbon emissions as the power mix decarbonizes.

• Improving energy efficiency: VSD and precise control lower energy consumption during off-design operation, improving oxygen production efficiency per unit energy.

• Driving domestic supply-chain localization: The 40 MW domestically produced demonstration will stimulate local manufacturing and technology upgrading for high-power motors, converters, cooling systems and monitoring equipment.

• Demonstration effect: As a national demonstration, the project generates a repeatable technical template that encourages other large industrial users to adopt high-efficiency electric drives, amplifying carbon reduction benefits.

Suggested KPIs & Maintenance Strategy

Key KPIs:

• Availability ≥ 98%

• Energy consumption (kWh / Nm³ O₂) meeting or exceeding design target

• Start-up current peaks within grid allowance

• Winding/bearing temperature rise stable within design margins

Maintenance & operation:

• Establish an online monitoring center for temperature, vibration, cooling flow and VSD parameters and implement predictive maintenance

• Maintain a pool of critical spare parts and train local teams with emergency response drills

The China Coal Yulin 85,000 Nm³/h ASU project, featuring a domestically produced ≈40 MW class ultra-high-power electric drive, represents an important milestone in China’s large-power industrial electrification and equipment localization. The demonstration enhances domestic equipment autonomy for coal-chemical and air-separation industries, promotes supply-chain technology upgrades, reduces carbon emissions through electrification, and offers a practical engineering pathway for large industrial users to adopt high-efficiency electric drives.