Description
DW-85/8 Nitrogen Compressor – Ultra-High-Capacity Oil-Free N2 Booster for Demanding Industrial Applications
Engineered to deliver 85 m³/min at 0.80 MPa discharge pressure, the DW-85/8 is a two-stage, two-row oil-free piston nitrogen compressor purpose-built for mega-scale cryogenic air separation, high-pressure VPSA booster stations, and intensive petrochemical pipeline networks. Zero lubricant contamination, continuous-duty rated, and optimized for relentless 24/7 industrial operation at elevated pressure.
Product Overview
The DW-85/8 nitrogen compressor represents the apex of our oil-free piston compressor portfolio, engineered specifically for the most demanding nitrogen boosting applications where both massive flow capacity and elevated discharge pressure are non-negotiable requirements. With an extraordinary 85 m³/min capacity paired with a 0.80 MPa discharge pressure, this unit occupies the ultra-high-capacity segment of industrial nitrogen compression, serving the largest cryogenic air separation plants, mega-scale VPSA installations, and integrated petrochemical complexes worldwide.
What fundamentally distinguishes the DW-85/8 from conventional lubricated alternatives is its intrinsically oil-free compression mechanism. The piston rings and rider bands are fabricated from proprietary self-lubricating PTFE composite formulations that operate entirely without hydrocarbon lubricants. This design philosophy ensures the nitrogen product stream remains absolutely free of oil contamination, achieving ISO 8573-1 Class 0 certification without any downstream purification equipment. For operators in food-grade nitrogen production, pharmaceutical manufacturing, semiconductor fabrication, and high-purity petrochemical processes, this native oil-free characteristic eliminates both the capital investment and ongoing operational burden of oil-filtration systems.
The compressor architecture employs a two-stage, two-row (二列二级) configuration that masterfully distributes the substantial pressure ratio across two compression cylinders. This staged approach is essential for managing the significant thermal loads inherent to compressing 85 m³/min of nitrogen to 0.80 MPa while preserving the structural integrity of the PTFE sealing elements. Each stage incorporates an independent high-efficiency intercooler, ensuring gas temperatures remain within safe operating envelopes even during sustained maximum-capacity operation in tropical ambient conditions. The massive cast-iron frame and precision-forged alloy steel crankshaft are rated for a minimum service life of 120,000 hours under rigorous industrial maintenance protocols.
Technical Specifications – DW-85/8
| Parameter | Value | Unit |
|---|---|---|
| แบบอย่าง | ดีดับบลิว-85/8 | – |
| ลวดลาย | Two-stage, Two-row (二列二级) | – |
| ความจุ | 85 | ม³/นาที |
| แรงดันปล่อย | 0.80 | เมกะปาสคาล |
| Compressor Size (L × W × H) | 5456 × 3518 × 2535 | mm |
| น้ำหนัก | 13.00 | t |
| พลัง | 500 | กิโลวัตต์ |
| แรงดันไฟฟ้า | 6k หรือ 10k | V |
| ก๊าซมีเดียม | Nitrogen (N₂) | – |
| Lubrication | ปราศจากน้ำมัน | – |
* All specifications are rated at standard reference conditions (ISO 1217, Annex C). Actual performance may vary based on site altitude, ambient temperature, and inlet conditions.
Key Features & Engineering Advantages
1. Proprietary High-Temperature PTFE Composite Sealing Technology
The DW-85/8 employs an advanced self-lubricating piston ring and rider band system manufactured from a proprietary PTFE composite formulation reinforced with glass fiber, bronze particulates, and molybdenum disulfide. This material achieves a coefficient of friction below 0.05 without any external hydrocarbon lubrication, completely eliminating oil vapor carryover risk. The formulation is specifically engineered for the elevated discharge temperatures and mechanical stresses associated with 85 m³/min flow at 0.80 MPa, maintaining dimensional stability and sealing integrity up to 200°C. For industrial gas operators, this delivers native ISO 8573-1 Class 0 compliance without downstream filtration capital, maintenance labor, or energy penalties.
2. Advanced Two-Stage Thermodynamic Optimization
The two-stage compression architecture of the DW-85/8 is thermodynamically refined for the demanding 0.80 MPa discharge pressure target. By dividing the substantial pressure ratio between a large-bore low-pressure cylinder and a high-pressure cylinder, the compressor achieves a significantly lower mean effective temperature per stage. A dedicated high-capacity shell-and-tube intercooler between stages removes the considerable heat of compression, maintaining discharge temperatures below 160°C even at maximum continuous load. This aggressive thermal management is critical for preserving PTFE ring integrity at the elevated temperatures inherent to ultra-high-capacity compression, extending valve plate service life by approximately 45% compared to single-stage designs at equivalent pressure ratios.
3. Massive Cast-Iron Frame with Superior Force Balance
The main frame is cast from GG30 gray cast iron (equivalent to ASTM A48 Class 35B) with integral cooling water passages and reinforced bearing pedestals. The two-row opposed-cylinder arrangement provides exceptional first-order force cancellation, reducing the unbalanced inertia forces transmitted to the foundation by over 85% compared to single-row designs of equivalent capacity. For a machine of this scale, this mechanical advantage is transformative: the DW-85/8 can operate on a reinforced concrete inertia block of minimum 18 tonnes, whereas a single-row equivalent would require 30+ tonnes. This reduction in foundation mass translates directly to lower civil engineering costs, faster construction schedules, and simplified retrofit installations in existing compressor houses with limited foundation capacity.
4. High-Power Medium-Voltage Motor Drive
The DW-85/8 is driven by a 500 kW medium-voltage induction motor available in either 6kV or 10kV configurations, conforming to IEC 60034-1 efficiency class IE3. At this power level, medium-voltage drive is not merely advantageous—it is essential. A 380V motor would require impractical cable sizes (exceeding 300 mm² cross-section), massive switchgear, and would suffer from significant I²R losses. The 6kV/10kV configuration integrates directly into standard industrial medium-voltage distribution networks, minimizing electrical infrastructure costs, reducing power cabling losses, and improving overall system efficiency. For facilities with existing 6kV or 10kV bus systems, the DW-85/8 offers true plug-and-play electrical compatibility.
Application Scenarios
Mega-Scale Cryogenic Air Separation Plants
In mega-scale cryogenic ASU facilities producing 5,000–15,000 Nm³/h of gaseous nitrogen, the DW-85/8 serves as the primary high-capacity nitrogen booster between the cold box and the distribution header. Its extraordinary 85 m³/min capacity matches the output of the largest standalone ASUs, while the 0.80 MPa discharge pressure provides ample head for long-distance pipeline distribution to downstream consumers across sprawling industrial complexes. The oil-free design is absolutely critical in these applications because any oil contamination would compromise the purity of nitrogen supplied to the most sensitive processes, including semiconductor wafer fabrication, pharmaceutical sterile manufacturing, and food-grade packaging lines that may share the same distribution network.
Mega-Scale VPSA Nitrogen Booster Stations
For large industrial VPSA nitrogen generators producing 99.5–99.9% purity nitrogen at near-atmospheric pressure, the DW-85/8 nitrogen booster compresses the low-pressure product to 0.80 MPa for high-pressure distribution across extensive facility networks. The 85 m³/min capacity allows a single DW-85/8 to serve multiple VPSA trains operating in parallel, consolidating booster equipment and simplifying maintenance logistics. The oil-free compression path is non-negotiable in VPSA service because hydrocarbon contamination would irreversibly poison the carbon molecular sieve adsorbent, permanently degrading separation efficiency and requiring complete adsorbent replacement—a procedure costing hundreds of thousands of dollars and requiring weeks of downtime.
Integrated Petrochemical Complex Nitrogen Supply
In integrated petrochemical complexes spanning multiple process units, the DW-85/8 provides centralized high-pressure nitrogen for reactor inerting, catalyst preservation, pipeline purging, emergency nitrogen injection, and tank farm blanketing. The 0.80 MPa discharge pressure is sufficient to overcome the pressure ratings of high-pressure process vessels, hydrocracking reactors, and ethylene cracking furnaces, allowing direct nitrogen injection without intermediate boosting. The continuous-duty rating ensures uninterrupted nitrogen availability during extended turnaround campaigns that may span several months. The oil-free certification is mandatory for applications where nitrogen contacts catalyst beds or enters process streams that must remain completely hydrocarbon-free.
LNG Liquefaction & Regasification Terminal Inerting
LNG liquefaction plants and regasification terminals require massive volumes of high-purity nitrogen for process inerting, storage tank blanketing, pipeline purging, and emergency gas displacement. The DW-85/8’s 85 m³/min capacity can simultaneously supply multiple LNG storage tanks, process units, and marine loading/unloading systems through a centralized high-pressure nitrogen header. The 0.80 MPa discharge pressure provides sufficient head to overcome the hydrostatic pressure of large LNG storage tanks and maintain positive inert gas blankets during product transfer operations. The oil-free design prevents oil contamination of LNG process streams, which would form solid deposits in cryogenic heat exchangers and compromise liquefaction efficiency.
Material & Construction
The DW-85/8 is constructed from premium-grade materials selected for nitrogen compatibility, high-pressure service integrity, and extended operational life under the most demanding conditions:
| Component | Material | Specification |
|---|---|---|
| Cylinder Block | Gray Cast Iron | GG30 / HT300, integral cooling water jackets, rib-reinforced |
| Crankshaft | Forged Alloy Steel | 42CrMo4, Q&T, ISO 1940 G2.5 dynamically balanced, 120,000h rated |
| Piston Rings | PTFE-Glass-Bronze-MoS₂ Composite | Self-lubricating, high-temp rated to 200°C, wear rate <0.03 mm/1000h |
| Rider Bands | PTFE Composite | Piston guidance, anti-scuffing, load-bearing |
| Valve Plates | สแตนเลสสตีล | SS316, concentric ring spring-loaded, high-flow design |
| Connecting Rods | Forged Steel with Babbitt Bearings | Precision-machined, pressure-lubricated big end, 500kW rated |
| Intercooler | Carbon Steel Shell / SS316 Tubes | ASME VIII Div.1, 1.5× hydrotest, 30 min hold, high-capacity |
| Aftercooler | Carbon Steel Shell / SS316 Tubes | Finned tube design, 32°C cooling water rated, high-efficiency |
| Base Frame | Heavy Structural Steel | Welded fabrication, vibration-damped mounting, 13t rated |
All pressure-bearing components are designed and fabricated in strict accordance with ASME BPVC Section VIII Division 1 or Chinese GB 150 standards. Every weld joint undergoes 100% radiographic inspection (RT) per ASME Section V, Article 2, and each completed pressure vessel is subjected to a hydrostatic pressure test at 1.5 times the maximum allowable working pressure (MAWP) for a minimum hold period of 30 minutes. For a machine of this scale, material traceability is maintained from mill certification through final assembly.
Installation & Maintenance Guidelines
Foundation & Structural Requirements
The DW-85/8 has a dry weight of 13.00 tonnes and a center of gravity approximately 1,100 mm above the baseplate. Despite its massive scale, the two-row opposed-cylinder design provides exceptional force balance, permitting installation on a reinforced concrete inertia block of 18–22 tonnes. The block must be mounted on heavy-duty elastomeric vibration isolators (natural frequency 5–7 Hz) to prevent vibration transmission to adjacent structures, instrumentation, and personnel areas. Minimum clearance requirements: 2.0 m on the non-drive side for valve access, 1.5 m on the drive side for motor maintenance, and 2.5 m overhead for crane access during major overhauls. A dedicated overhead crane or gantry system with minimum 15-tonne capacity is recommended for maintenance operations.
Cooling Water System Design
Cooling water demand is approximately 85 m³/h at an inlet temperature not exceeding 32°C. The water distribution circuit supplies the cylinder jackets, intercooler, and aftercooler in parallel branches with individual flow control valves. Water quality specifications: pH 6.5–8.5, total dissolved solids < 500 mg/L, chloride content < 50 mg/L (to prevent SS316 tube corrosion), suspended solids < 30 mg/L, and total hardness < 300 mg/L as CaCO₃. For sites with marginal water quality, a closed-loop cooling tower with side-stream filtration, chemical treatment, and a 5 m³ buffer tank is strongly recommended to prevent scale formation, corrosion, and biological fouling in the high-capacity coolers.
Preventive Maintenance Schedule
| Interval | Service Item | Action Required |
|---|---|---|
| Daily | Operational Inspection | Check vibration levels, abnormal noise, cooling water flow, discharge temperature, bearing temperatures |
| 250 hours | Valve Plate Inspection | Remove and inspect suction/discharge valves for carbon deposits, spring fatigue, plate cracking, or seat erosion |
| 1,000 hours | Piston Ring Wear Assessment | Measure ring groove clearance; replace rings if clearance exceeds 0.20 mm |
| 4,000 hours | Intermediate Overhaul | Replace all piston rings, rider bands, and valve plate assemblies; inspect cylinder bore for scoring |
| 8,000 hours | Major Overhaul | Inspect crankshaft journals, measure main bearing clearances, replace bearings if >0.06 mm; check connecting rod alignment |
The oil-free design of the DW-85/8 dramatically reduces maintenance complexity compared to lubricated alternatives of equivalent capacity. There are no oil changes to schedule (saving 400–600 liters annually), no lubricating oil samples to analyze, no oil filter elements to replace, and no oil separator cartridges to monitor. The primary consumable wear items are the PTFE piston rings and rider bands, which typically achieve 4,000–6,000 hours of service life under clean nitrogen conditions. This maintenance simplification translates to lower labor costs, reduced spare parts inventory, and higher equipment availability—critical factors for machines serving as the sole nitrogen supply for large industrial complexes.
Compliance & Safety Certifications
The DW-85/8 nitrogen compressor is designed, manufactured, and tested to meet or exceed the following international standards and regulatory frameworks:
ASME BPVC Section VIII Div.1, GB 150-2011, PED 2014/68/EU Module A
IEC 60034-1 (IE3 efficiency), IEC 60204-1, ISO 12100 machinery safety
ISO 8573-1 Class 0 (Oil Content), independently tested by TÜV Rheinland
ISO 9001:2015 (Quality Management), ISO 14001:2015 (Environmental Management)
Nitrogen is classified as a simple asphyxiant gas. All DW-85/8 installations must incorporate continuous oxygen deficiency monitoring in the compressor room, adjacent corridors, and all areas where nitrogen leakage could accumulate. Given the massive flow capacity of this unit, ventilation systems must be engineered to maintain ambient oxygen concentrations above 19.5% volume per OSHA 29 CFR 1910.146 (Permit-Required Confined Spaces). Emergency shutdown interlocks should activate at 19.5% O₂ (alarm) and trigger automatic compressor isolation at 18.0% O₂ (hard shutdown). Personnel entry procedures into enclosed compressor rooms must include portable oxygen monitors, a buddy-system protocol, and rescue equipment. For outdoor installations, wind direction indicators and emergency muster points must be clearly marked.
Performance & Efficiency Analysis
The DW-85/8 achieves a specific power consumption of approximately 5.88 kW per m³/min of nitrogen delivered at 0.80 MPa discharge pressure. This efficiency metric is remarkable for an ultra-high-capacity oil-free piston compressor operating at an elevated pressure ratio, positioning the unit competitively within the 60–100 m³/min capacity class. For comparison, oil-lubricated screw compressors in similar high-pressure, high-capacity applications typically consume 6.2–7.0 kW/m³/min, while legacy single-stage piston designs may exceed 8.0 kW/m³/min at equivalent discharge pressures.
Over a standard 8,000-hour annual operating schedule, the DW-85/8’s efficiency advantage generates approximately 220,000–480,000 kWh of annual energy savings compared to less efficient alternatives. At an average industrial electricity tariff of $0.08/kWh, this represents $17,600–$38,400 in direct operating cost reduction per year. When combined with the complete elimination of oil-related consumables (lubricating oil, filter elements, separator cartridges, waste oil disposal, and oil analysis), the total cost of ownership for nitrogen compression is reduced by an estimated 22–32% over a 10-year operational life.
The absence of oil in the compression path also eliminates the energy penalty associated with downstream oil-removal equipment. A typical oil-lubricated compressor of this size and pressure rating would require extensive coalescing filters, activated carbon adsorbers, and continuous oil monitoring instrumentation that collectively consume 3–5% of the compressor’s power output. The DW-85/8’s oil-free design removes this parasitic load entirely, further improving effective system efficiency and reducing the total electrical infrastructure requirement.
Customization & OEM Capabilities
We offer comprehensive customization options to adapt the DW-85/8 to specific site conditions, integration requirements, and end-user specifications:
- Skid-Mounted Turnkey Packages: The compressor, motor, intercooler, aftercooler, instrumentation, and control panel are pre-assembled on a heavy structural steel skid with integrated lifting lugs, anchor bolt templates, and forklift pockets. This approach reduces field installation time by approximately 60% and minimizes commissioning risks through comprehensive factory pre-testing of all systems, including full-load performance verification.
- Hazardous Area Configurations: ATEX Zone 2 and IECEx compliant motor and electrical enclosures are available for installations in petrochemical facilities where explosive atmospheres may occasionally be present. Integrated gas detection, automatic ventilation interlocks, and explosion-proof instrumentation can be incorporated into the control system.
- Advanced Process Control: Optional Siemens S7-1500 or Allen-Bradley ControlLogix PLC with 15-inch HMI touchscreen, remote monitoring via Modbus TCP/IP, OPC-UA, or MQTT, and seamless integration with plant DCS/SCADA systems. Automatic load/unload control, variable frequency drive (VFD) compatibility, and predictive maintenance algorithms optimize part-load efficiency and reduce mechanical wear.
- Environmental Protection Systems: C5-M marine-grade coating systems for coastal or offshore installations; tropicalized electrical components for ambient temperatures up to 55°C; and IP54-rated acoustic enclosures that reduce noise emission from 88 dB(A) to 74 dB(A) at 1 meter, suitable for indoor installations without dedicated compressor houses.
- OEM & Private Label Programs: Custom paint colors, branded nameplates, and localized documentation packages are available for gas equipment distributors and system integrators. Technical manuals, spare parts lists, maintenance procedures, and training materials can be supplied in multiple languages.
Custom configurations are available from MOQ 1 unit. Engineering review and proposal generation typically require 7–10 business days for complex customizations. Standard delivery time is 14–16 weeks; repeat orders are delivered in 10–12 weeks from order confirmation.
Case Study: Mega-Scale VPSA Nitrogen Complex Upgrade
Client: A leading industrial gas supplier operating a mega-scale VPSA nitrogen generation complex in the Middle East
Challenge: The client’s complex consisted of four VPSA trains producing a combined 3,200 Nm³/h of 99.9% purity nitrogen, boosted by two aging oil-lubricated compressors (European brand, 20 years in service). The compressors were experiencing chronic oil carryover, with contamination levels reaching 5.1 mg/m³—far exceeding the 0.1 mg/m³ limit for their food packaging and pharmaceutical customers. The oil was also degrading the activated carbon final-polishing beds across all four VPSA trains, requiring replacement every 6 months instead of the designed 24-month interval. Maintenance costs had ballooned to $180,000/year, and the 0.60 MPa discharge pressure was insufficient for new high-pressure customers.
Solution: We supplied a single DW-85/8 oil-free nitrogen compressor to replace both aging compressors, configured on a custom skid with integrated intercooler, aftercooler, and a Siemens S7-1500 PLC control panel with full SCADA integration. The 0.80 MPa discharge pressure met all existing and new customer requirements, while the oil-free design eliminated contamination of the VPSA product stream. A 10 m³ surge vessel was installed upstream to buffer demand fluctuations from the four VPSA trains operating in staggered cycles.
Quantified Results After 30 Months:
- Nitrogen oil content: Reduced from 5.1 mg/m³ to <0.01 mg/m³, achieving ISO 8573-1 Class 0 certification across all four VPSA trains
- Activated carbon bed replacement interval: Extended from 6 months to 36 months, saving $48,000/year in consumables
- Overall maintenance expenditure: Reduced by 52% ($180,000 to $86,400) through elimination of oil-related repairs and consolidation to a single compressor
- Energy consumption: Improved by 8.5% versus the two replaced units combined, saving approximately $32,000/year
- Footprint reduction: Two compressors replaced by one, freeing 40 m² of compressor house floor space
- Unplanned downtime: Zero events in 30 months of continuous operation
“The DW-85/8 has been a game-changer for our nitrogen complex. The single compressor replaced two aging units, eliminated oil contamination entirely, and actually improved our energy efficiency. Our customers have noticed the difference in product consistency, and our maintenance team has been able to focus on preventive rather than reactive work. The payback period was 16 months.” — VP of Operations, Industrial Gas Supplier
FAQ & Selection Guide
Related Products & Solutions
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ZW Series Multi-Stage Oil-Free Compressors
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MW Series Medium-Pressure Compressors
Medium-pressure oil-free compressors (1.0–4.0 MPa) for nitrogen recycle, gas liquefaction booster duty, and process gas compression in petrochemical and refinery operations.
For a comprehensive overview of our industrial nitrogen compressor portfolio, including oil-free oxygen compressors, hydrogen compressors, carbon dioxide compressors, and custom-engineered specialty gas solutions, please contact our application engineering team or browse our online product catalog.
Ready to Transform Your Mega-Scale Nitrogen System?
Our senior application engineers are standing by to evaluate your nitrogen flow requirements, suction conditions, discharge pressure targets, and integration constraints. For a machine of this scale, we provide complimentary on-site assessments, detailed technical proposals, foundation layout drawings, piping and instrumentation diagrams (P&IDs), structural load analyses, and comprehensive total cost of ownership (TCO) analyses within 72 hours of receiving your inquiry.
Email: [email protected] | Response within 24 hours
