説明
LW-40/4 Nitrogen Compressor – Oil-Free N2 Booster for Medium-Pressure Industrial Gas Distribution
Engineered to deliver 40 m³/min at 0.40 MPa discharge pressure, the LW-40/4 is a two-stage, two-row oil-free piston nitrogen compressor purpose-built for cryogenic air separation backup, VPSA nitrogen boosting, and medium-pressure pipeline distribution networks. Zero oil contamination, continuous-duty rated, and optimized for 24/7 industrial operation.
製品概要
The LW-40/4 nitrogen compressor occupies a critical position in our oil-free piston compressor portfolio, bridging the gap between low-pressure nitrogen generation and medium-pressure distribution requirements. With a rated capacity of 40 m³/min and a discharge pressure of 0.40 MPa, this unit is the workhorse of medium-scale cryogenic air separation plants, VPSA nitrogen booster stations, and industrial gas pipeline networks.
What distinguishes the LW-40/4 from conventional lubricated alternatives is its fully oil-free compression path. The piston rings and rider bands are fabricated from self-lubricating PTFE composite materials that operate without hydrocarbon lubricants, ensuring the nitrogen stream remains completely free of oil contamination. This characteristic is indispensable for applications requiring ISO 8573-1 Class 0 certification, including food packaging nitrogen, pharmaceutical inerting, and semiconductor process gas supply.
The compressor architecture follows a two-stage, two-row (二列二级) layout that divides the total pressure ratio across two compression cylinders. This staged approach reduces the discharge temperature per stage, improves volumetric efficiency, and extends the service life of valves and piston rings. Each compression stage is equipped with an independent intercooler, ensuring gas temperatures remain within safe operating envelopes even under sustained maximum load conditions.
Technical Specifications – LW-40/4
| Parameter | Value | Unit |
|---|---|---|
| モデル | LW-40/4 | – |
| パターン | Two-stage, Two-row (二列二级) | – |
| 容量 | 40 | m³/分 |
| 吐出圧力 | 0.40 | MPa |
| Compressor Size (L × W × H) | 3260 × 1655 × 2548 | mm |
| 重さ | 4.50 | t |
| 力 | 160 | kW |
| 電圧 | 380 | V |
| ガス媒体 | Nitrogen (N₂) | – |
| Lubrication | オイルフリー | – |
* 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. Oil-Free PTFE Piston Ring Technology
The LW-40/4 utilizes a proprietary self-lubricating piston ring and rider band assembly manufactured from high-density PTFE composites reinforced with glass fiber and bronze particulates. This material combination achieves a coefficient of friction below 0.08 without any external lubrication, eliminating the risk of oil vapor carryover into the nitrogen product stream. For buyers operating in regulated industries, this translates directly to ISO 8573-1 Class 0 compliance without the capital and operating costs of downstream oil-filtration systems.
2. Staged Compression with Intercooling
The two-stage compression architecture of the LW-40/4 is thermodynamically optimized for the 0.40 MPa discharge pressure target. By splitting the pressure ratio between a low-pressure cylinder and a high-pressure cylinder, the compressor achieves a lower mean effective temperature per stage. A dedicated shell-and-tube intercooler between stages removes the heat of compression, maintaining discharge temperatures below 155°C and preventing thermal degradation of the PTFE sealing elements. This thermal management strategy extends valve plate life by approximately 35% compared to single-stage designs operating at equivalent pressure ratios.
3. Robust Cast-Iron Frame with Force Balance
The main frame is cast from GG25 gray cast iron (equivalent to ASTM A48 Class 30B) with integral cooling water passages. The two-row opposed-cylinder arrangement provides natural first-order force cancellation, reducing the unbalanced inertia forces transmitted to the foundation by over 80% compared to single-row designs. This mechanical advantage allows the LW-40/4 to operate on a lighter foundation block (minimum 6 tonnes versus 10+ tonnes for single-row equivalents), reducing civil engineering costs and simplifying retrofit installations in existing compressor houses.
4. Standard 380V Industrial Motor Drive
The LW-40/4 is driven by a 160 kW, 380V, 50Hz three-phase induction motor conforming to IEC 60034-1 efficiency class IE3. The standard 380V configuration eliminates the need for medium-voltage switchgear or step-down transformers, making this model particularly attractive for facilities with existing low-voltage distribution infrastructure. For sites with 6kV or 10kV bus systems, an optional motor with integrated step-down transformer can be supplied on a common skid.
Application Scenarios
Cryogenic Air Separation Backup & Peak Shaving
In cryogenic ASU operations, the LW-40/4 serves as a reliable backup nitrogen booster or peak-shaving compressor. When the primary ASU experiences a cold box upset or requires maintenance, the LW-40/4 can maintain nitrogen supply to critical downstream consumers from liquid nitrogen storage vaporizers. Its 0.40 MPa discharge pressure is sufficient to feed medium-pressure distribution headers serving steel mill inerting, chemical reactor blanketing, and LNG plant purge gas systems. The oil-free design is particularly critical in backup scenarios where nitrogen purity cannot be compromised during primary system outages.
VPSA Nitrogen Booster Stations
Vacuum Pressure Swing Adsorption (VPSA) nitrogen generators produce gaseous nitrogen at near-atmospheric pressure (0.05–0.10 MPa). The LW-40/4 nitrogen booster compresses this low-pressure product to 0.40 MPa for distribution to point-of-use applications. The oil-free compression path is essential in VPSA service because any hydrocarbon contamination would poison the carbon molecular sieve adsorbent, permanently degrading the nitrogen generator’s separation efficiency and requiring costly adsorbent replacement.
Petrochemical Pipeline Nitrogen Injection
In petrochemical and refinery operations, nitrogen is injected into process pipelines and storage vessels to maintain inert atmospheres during startup, shutdown, and product changeover procedures. The LW-40/4’s 0.40 MPa discharge pressure provides adequate head to overcome pipeline friction losses over distances up to 2 km, making it suitable for centralized nitrogen supply to multiple process units. The continuous-duty rating ensures uninterrupted nitrogen availability during extended maintenance campaigns that may last several weeks.
Food & Beverage Modified Atmosphere Packaging
Large-scale food packaging facilities require high-flow nitrogen for modified atmosphere packaging (MAP) and controlled atmosphere storage. The LW-40/4’s 40 m³/min capacity can simultaneously supply multiple high-speed packaging lines, while its oil-free certification ensures compliance with FDA 21 CFR 173.310 (food-grade nitrogen) and EU Regulation 231/2012. The absence of oil contamination eliminates the risk of off-flavors, rancidity, or product discoloration that can occur when lubricated compressors are used in food-contact applications.
Material & Construction
Every component of the LW-40/4 is selected for compatibility with nitrogen service, corrosion resistance, and long-term mechanical integrity:
| Component | Material | 仕様 |
|---|---|---|
| Cylinder Block | Gray Cast Iron | GG25 / HT250, integral water jackets |
| Crankshaft | Forged Alloy Steel | 42CrMo4, Q&T, ISO 1940 G2.5 balanced |
| Piston Rings | PTFE-Glass-Bronze Composite | Self-lubricating, wear rate <0.05 mm/1000h |
| Rider Bands | PTFE Composite | Guide piston, prevent cylinder contact |
| Valve Plates | ステンレス鋼 | SS316, spring-loaded concentric ring design |
| Connecting Rods | Forged Steel with Babbitt Bearings | Precision-machined, oil-lubricated big end |
| Intercooler | Carbon Steel Shell / SS304 Tubes | ASME VIII Div.1, 1.5× hydrotest |
| Aftercooler | Carbon Steel Shell / SS304 Tubes | Finned tube design, 32°C cooling water |
All pressure vessels are designed and fabricated in accordance with ASME BPVC Section VIII Division 1 or Chinese GB 150 standards. Every weld joint undergoes 100% radiographic testing (RT) per ASME Section V, Article 2, and each completed vessel is subjected to a hydrostatic pressure test at 1.5 times the maximum allowable working pressure (MAWP) for a minimum hold time of 30 minutes.
Installation & Maintenance Guidelines
Foundation & Mounting
The LW-40/4 has a dry weight of 4.50 tonnes and a center of gravity approximately 850 mm above the baseplate. Due to the two-row opposed-cylinder design, the unbalanced forces are minimal, allowing installation on a reinforced concrete inertia block of 6–8 tonnes. The block should be mounted on vibration isolation pads (natural frequency 6–8 Hz) to prevent vibration transmission to adjacent structures. Minimum clearance requirements: 1.5 m on the non-drive side for valve access, 1.2 m on the drive side for motor maintenance, and 2.0 m overhead for crane access during major overhauls.
Cooling Water Requirements
The LW-40/4 requires approximately 38 m³/h of cooling water at an inlet temperature not exceeding 32°C. The cooling water system must supply the cylinder jackets, intercooler, and aftercooler in parallel circuits. Water quality specifications: pH 6.5–8.5, total dissolved solids < 500 mg/L, chloride content < 50 mg/L (to prevent SS304 tube corrosion), and suspended solids < 30 mg/L. For sites with marginal water quality, a closed-loop cooling tower with side-stream filtration and chemical treatment is strongly recommended.
Preventive Maintenance Schedule
| Interval | Service Item | Action Required |
|---|---|---|
| Daily | Operational Inspection | Check vibration levels, abnormal noise, cooling water flow, discharge temperature |
| 250 hours | Valve Inspection | Remove and inspect suction/discharge valve plates for carbon deposits or cracking |
| 1,000 hours | Piston Ring Measurement | Measure ring groove clearance; replace rings if clearance exceeds 0.25 mm |
| 4,000 hours | Intermediate Overhaul | Replace all piston rings, rider bands, and valve plate assemblies |
| 8,000 hours | Major Overhaul | Inspect crankshaft journals, measure bearing clearances, replace main bearings if >0.08 mm |
A key economic advantage of the LW-40/4 is the absence of lubricating oil in the compression path. Unlike oil-lubricated compressors that require quarterly oil changes, monthly oil analysis, and annual separator element replacement, the LW-40/4 eliminates these consumables entirely. The only recurring 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.
Compliance & Safety Certifications
The LW-40/4 nitrogen compressor is designed, manufactured, and tested to meet 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 LW-40/4 installations must incorporate continuous oxygen deficiency monitoring in the compressor room and adjacent areas. Ventilation systems must be designed 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 must include portable O₂ monitors and buddy-system protocols.
Performance & Efficiency Analysis
The LW-40/4 achieves a specific power consumption of approximately 4.00 kW per m³/min of nitrogen at 0.40 MPa discharge pressure. This efficiency metric positions the unit in the upper tier of oil-free piston compressors within the 30–50 m³/min capacity range. For context, typical oil-lubricated screw compressors operating at equivalent pressure ratios consume 4.4–4.9 kW/m³/min, while legacy single-stage piston designs may exceed 5.2 kW/m³/min.
Over a standard 8,000-hour annual operating schedule, the LW-40/4’s efficiency advantage yields approximately 128,000–288,000 kWh of annual energy savings compared to less efficient alternatives. At an average industrial electricity tariff of $0.08/kWh, this translates to $10,240–$23,040 in direct operating cost reduction per year. When combined with the elimination of oil-related consumables (lubricating oil, filter elements, separator cartridges, waste oil disposal), the total cost of ownership for nitrogen compression is reduced by an estimated 25–35% 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 requires coalescing filters, activated carbon adsorbers, and monitoring instrumentation that collectively consume 3–5% of the compressor’s power output. The LW-40/4’s oil-free design removes this parasitic load entirely.
Customization & OEM Capabilities
We offer comprehensive customization options to adapt the LW-40/4 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 structural steel skid with integrated lifting lugs and anchor bolt templates. This approach reduces field installation time by approximately 60% and minimizes commissioning risks.
- 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. Gas detection and automatic ventilation interlocks can be integrated into the control system.
- Advanced Process Control: Optional Siemens S7-1200 or Allen-Bradley CompactLogix PLC with 10-inch HMI touchscreen, remote monitoring via Modbus TCP/IP or OPC-UA, and seamless DCS/SCADA integration. Automatic load/unload control and variable speed drive (VFD) compatibility optimize part-load efficiency.
- Environmental Protection: 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 85 dB(A) to 72 dB(A) at 1 meter.
- OEM & Private Label: Custom paint colors, branded nameplates, and documentation packages are available for system integrators and gas equipment distributors. Technical manuals, spare parts lists, and maintenance procedures can be supplied in local languages.
Custom configurations are available from MOQ 1 unit. Engineering review and proposal generation typically require 5–7 business days. Prototype delivery schedules range from 12–14 weeks; repeat orders are delivered in 8–10 weeks from order confirmation.
Case Study: VPSA Nitrogen Booster Upgrade in Southeast Asia
Client: A major industrial gas supplier operating a VPSA nitrogen generation facility in Vietnam
Challenge: The client’s existing oil-lubricated nitrogen booster (European brand, 15 years in service) was experiencing progressive oil carryover into the nitrogen product. Oil contamination levels reached 2.8 mg/m³, exceeding the 0.1 mg/m³ limit specified by their food packaging customers. The oil was also degrading the activated carbon final-polishing bed, requiring replacement every 8 months instead of the designed 24-month interval.
Solution: We supplied an LW-40/4 oil-free nitrogen compressor as a direct replacement, configured on a custom skid with integrated intercooler, aftercooler, and a Siemens S7-1200 PLC control panel. The skid footprint was engineered to match the existing foundation, eliminating the need for civil modifications. A 2 m³ surge vessel was added upstream to dampen pressure pulsations from the VPSA adsorption cycle.
Quantified Results After 24 Months:
- Nitrogen oil content: Reduced from 2.8 mg/m³ to <0.01 mg/m³, achieving ISO 8573-1 Class 0 certification
- Activated carbon bed replacement interval: Extended from 8 months to 30 months, saving $12,000/year in consumables
- Overall maintenance expenditure: Decreased by 38% due to elimination of oil changes, filter replacements, and separator overhauls
- Energy consumption: Improved by 7.2% versus the replaced unit, equivalent to $15,600/year savings at local electricity rates
- Unplanned downtime: Zero events in 24 months of continuous operation
“The LW-40/4 eliminated our oil contamination problem completely. Our food packaging customers no longer report quality issues, and our maintenance team has cut their service time by nearly half. The payback period was under 18 months.” — Facility Operations Director
FAQ & Selection Guide
Related Products & Solutions
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ZW Series Multi-Stage Oil-Free Compressors
Vertical, multi-stage oil-free compressors for oxygen, nitrogen, hydrogen, and specialty gases. Discharge pressures up to 9.00 MPa for high-pressure gas filling, cylinder charging, and chemical process applications.
MW Series Medium-Pressure Compressors
Medium-pressure oil-free compressors (1.0–4.0 MPa) optimized 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 product range, 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 Optimize Your Nitrogen Compression System?
Our application engineers are standing by to evaluate your nitrogen flow requirements, suction conditions, discharge pressure targets, and integration constraints. We provide complimentary technical proposals, foundation layout drawings, piping and instrumentation diagrams (P&IDs), and detailed total cost of ownership (TCO) analyses within 48 hours of receiving your inquiry.
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