Opis
3ZW-6/30 Nitrogen Compressor – Three-Stage Oil-Free N2 Booster for 3.00 MPa High-Pressure Process Applications
Engineered to deliver 6 m³/min at 3.00 MPa discharge pressure, the 3ZW-6/30 is a three-stage, three-row oil-free piston nitrogen compressor designed for ultra-high-pressure nitrogen injection, gas cylinder filling stations, and demanding chemical synthesis processes. Zero oil contamination, robust multi-stage architecture, and optimized for continuous-duty operation at extreme pressure.
Product Overview
Ten 3ZW-6/30 nitrogen compressor represents the pinnacle of our oil-free piston compressor technology, engineered specifically for applications that demand both substantial flow capacity and ultra-high discharge pressure. With a rated capacity of 6 m³/min and an exceptional 3.00 MPa discharge pressure, this unit occupies the high-pressure segment of our industrial nitrogen compressor portfolio, serving the most demanding process applications in the chemical, petrochemical, and gas distribution industries.
The “3ZW” designation signifies the three-stage, three-row (三列三级) architecture that is fundamental to achieving the 3.00 MPa discharge pressure while maintaining thermal stability and mechanical reliability. Each of the three compression stages operates at a moderate pressure ratio, with dedicated intercoolers between stages removing the heat of compression. This multi-staged approach is essential because the overall pressure ratio from atmospheric inlet to 3.00 MPa exceeds the safe operating limits of single-stage or two-stage designs, both in terms of discharge temperature and mechanical stress on the pistons and crankshaft.
What distinguishes the 3ZW-6/30 from conventional alternatives is its fully oil-free compression pathway. The piston rings and rider bands are precision-machined from advanced self-lubricating PTFE composite materials that operate without any hydrocarbon lubricants. At 3.00 MPa discharge pressure, the risk of oil vapor carryover is exponentially higher than at low-pressure applications, making the oil-free design not merely advantageous but absolutely mandatory for any application requiring high-purity nitrogen. The unit achieves ISO 8573-1 Class 0 certification natively, without downstream oil-filtration equipment.
Technical Specifications – 3ZW-6/30
| Parameter | Value | Unit |
|---|---|---|
| Model | 3ZW-6/30 | – |
| Wzór | Three-stage, Three-row (三列三级) | – |
| Pojemność | 6 | m³/min |
| Ciśnienie wylotowe | 3.00 | MPa |
| Compressor Size (L × W × H) | 1845 × 1660 × 2360 | mm |
| Waga | 3.00 | t |
| Moc | 75 | kW |
| Woltaż | 380 | V |
| Medium gazowe | Nitrogen (N₂) | – |
| Lubrication | Bez oleju | – |
* 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. Three-Stage Compression for Ultra-High Pressure
Ten three-stage, three-row architecture of the 3ZW-6/30 is the engineering foundation that makes 3.00 MPa discharge pressure achievable with oil-free piston technology. The overall pressure ratio of approximately 30:1 to 60:1 (from atmospheric inlet) is divided across three compression cylinders, with each stage operating at a pressure ratio of approximately 3:1 to 4:1. This staged approach is thermodynamically essential because single-stage compression to 3.00 MPa would produce discharge temperatures exceeding 300°C, far beyond the safe operating limit of PTFE sealing materials. Between each stage, a dedicated high-efficiency shell-and-tube intercooler removes the heat of compression, maintaining discharge temperatures below 155°C at all stages. This thermal management preserves PTFE ring integrity and extends valve plate life by approximately 50% compared to two-stage designs attempting equivalent pressure ratios.
2. Advanced High-Pressure Oil-Free PTFE Sealing System
The 3ZW-6/30 employs a proprietary self-lubricating piston ring and rider band assembly manufactured from ultra-high-performance PTFE composites specifically formulated for 3.00 MPa service. These rings are reinforced with glass fiber, bronze particulates, and molybdenum disulfide to achieve a coefficient of friction below 0.05 without any external hydrocarbon lubrication. At 3.00 MPa discharge pressure, the partial pressure of oil vapor would be approximately 10 times higher than at 0.30 MPa, making oil contamination exponentially more severe and more difficult to remove downstream. The 3ZW-6/30’s native oil-free design achieves ISO 8573-1 Class 0 certification without any downstream filtration, coalescing, or adsorption equipment. The PTFE formulation is rated for continuous operation at temperatures up to 185°C, with a safety margin that accommodates transient temperature excursions during startup and load changes.
3. Three-Row Opposed-Cylinder Force Balance
The main frame is cast from GG25 gray cast iron with reinforced wall sections and integral cooling water passages. The three-row opposed-cylinder arrangement provides superior force balance compared to single-row or two-row designs, with first-order and second-order inertial forces largely self-canceling. This mechanical advantage is particularly critical for high-pressure compressors where the peak gas forces on the pistons are substantially higher than in low-pressure applications. The three-row configuration reduces the unbalanced forces transmitted to the foundation by over 85% compared to single-row designs, permitting installation on a lighter reinforced concrete inertia block (minimum 5 tonnes) and reducing the risk of vibration-induced fatigue in connected piping systems. The compact dimensions—1845 × 1660 × 2360 mm—are remarkable for a three-stage compressor of this pressure class, achieved through a vertically stacked cylinder arrangement that minimizes the machine’s footprint.
4. Standard 380V Industrial Motor Drive
The 3ZW-6/30 is driven by a 75 kW, 380V, 50Hz three-phase induction motor conforming to IEC 60034-1 efficiency class IE3. The standard low-voltage configuration integrates directly into existing 380V industrial distribution panels without requiring medium-voltage switchgear or step-down transformers. This electrical simplicity is particularly valuable for the 3ZW-6/30 because its moderate power requirement (75 kW) does not justify the complexity and cost of medium-voltage infrastructure. The motor is directly coupled to the crankshaft through a flexible disc coupling, eliminating the maintenance burden and efficiency losses associated with belt or gearbox drives.
Application Scenarios
Ultra-High-Pressure Nitrogen Cylinder Filling
The 3ZW-6/30 is the ideal primary booster for nitrogen cylinder filling stations serving industrial, medical, and specialty gas markets. While the compressor’s 3.00 MPa discharge pressure does not reach the 15–20 MPa required for direct cylinder filling, it serves as a highly efficient intermediate stage that dramatically reduces the compression ratio required of downstream high-pressure filling compressors. In a typical filling station configuration, the 3ZW-6/30 boosts nitrogen from 0.05–0.10 MPa to 3.00 MPa, after which a compact high-pressure diaphragm or piston compressor completes the filling to 20 MPa. This staged approach improves overall system efficiency by 25–35% compared to single-stage high-pressure compression from atmospheric inlet. The oil-free design is mandatory for cylinder filling because any oil contamination would be trapped in the filled cylinders and delivered to end-users, potentially compromising their processes and exposing the filling station to liability.
Chemical Synthesis & High-Pressure Reactor Inerting
In chemical process plants, the 3ZW-6/30 nitrogen compressor provides ultra-high-pressure nitrogen for high-pressure reactor inerting, catalyst bed preservation, and emergency depressurization of process vessels. The 3.00 MPa discharge pressure is sufficient to inject nitrogen into reactors operating at pressures up to 2.5 MPa, maintaining positive inert gas blankets during all phases of operation. The three-stage compression ensures that the nitrogen remains thermally stable and free of oil contamination, which is critical in chemical synthesis where even trace contaminants can poison catalysts, initiate unwanted side reactions, or compromise product purity. The 6 m³/min capacity can serve multiple high-pressure reactors simultaneously through a centralized nitrogen header.
Gas Liquefaction & Cryogenic Storage Pressure Maintenance
In nitrogen liquefaction plants and cryogenic storage facilities, the 3ZW-6/30 serves as a high-pressure booster that compresses nitrogen vapor from storage tanks or recondensers to the pressure required for distribution or further processing. The 3.00 MPa discharge pressure is adequate for driving nitrogen through heat exchangers, recondensers, and distribution networks in small to medium liquefaction plants. The oil-free design is essential because any oil contamination in the high-pressure nitrogen would be carried into the cryogenic system, where it would freeze and block heat exchanger passages, causing operational failures and costly maintenance. The three-stage compression with intercooling ensures that the nitrogen remains at manageable temperatures throughout the compression process, preventing thermal damage to downstream cryogenic equipment.
Oil & Gas Well Nitrogen Injection
In oil and gas production operations, high-pressure nitrogen is injected into wells for enhanced oil recovery (EOR), well stimulation, and gas lift operations. The 3ZW-6/30’s 3.00 MPa discharge pressure is sufficient for many shallow to medium-depth well applications, where nitrogen is used to displace oil, reduce reservoir pressure, or lift production fluids to the surface. The oil-free design prevents hydrocarbon contamination of the reservoir, which could alter formation permeability and reduce oil recovery efficiency. The 6 m³/min capacity can support continuous nitrogen injection for extended well stimulation campaigns or intermittent gas lift operations for multiple wells.
Material & Construction
The 3ZW-6/30 is constructed from premium materials selected for ultra-high-pressure nitrogen compatibility, thermal resistance, and extended operational life:
| Component | Material | Specification |
|---|---|---|
| Cylinder Block (1st Stage) | Gray Cast Iron | GG25 / HT250, standard wall thickness |
| Cylinder Block (2nd Stage) | Gray Cast Iron | GG25 / HT250, reinforced wall + ribbing |
| Cylinder Block (3rd Stage) | Gray Cast Iron | GG25 / HT250, heavy-duty reinforced wall |
| Crankshaft | Forged Alloy Steel | 42CrMo4, Q&T, ISO 1940 G2.5 dynamically balanced |
| Piston Rings | PTFE-Glass-Bronze-MoS₂ Composite | Ultra-high-pressure rated, self-lubricating, 185°C max |
| Rider Bands | PTFE Composite | Piston guidance, anti-scuffing, wear rate <0.04 mm/1000h |
| Valve Plates | Stal nierdzewna | SS316, high-pressure concentric ring design |
| Intercoolers (×2) | Carbon Steel Shell / SS316 Tubes | ASME VIII Div.1, 1.5× hydrotest, 30 min hold |
| Aftercooler | Carbon Steel Shell / SS316 Tubes | High-pressure finned tube, 32°C cooling water |
| High-Pressure Piping | Seamless Stainless Steel | SS316, ANSI Class 900 flanges |
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. High-pressure piping systems are fabricated from seamless SS316 with ANSI Class 900 flanged connections to ensure leak-tight integrity at 3.00 MPa operating pressure.
Installation & Maintenance Guidelines
Foundation & Structural Requirements
The 3ZW-6/30 has a dry weight of 3.00 tonnes and a center of gravity approximately 800 mm above the baseplate. Thanks to the three-row opposed-cylinder design, unbalanced forces are minimal despite the ultra-high-pressure operation, permitting installation on a reinforced concrete inertia block of 5–6 tonnes. The block should be mounted on elastomeric vibration isolators (natural frequency 7–10 Hz). Minimum clearance requirements: 1.2 m on the non-drive side for valve access, 1.0 m on the drive side for motor maintenance, and 1.5 m overhead for crane access. Special attention must be paid to the high-pressure discharge piping, which must be properly supported with spring hangers and anchored to prevent vibration-induced fatigue at 3.00 MPa. All high-pressure connections must be verified with ultrasonic testing after installation.
Cooling Water System Design
Cooling water demand is approximately 15 m³/h at an inlet temperature not exceeding 32°C. The water distribution circuit supplies the cylinder jackets and two intercoolers in parallel branches. Given the three-stage compression and high pressure ratio, the intercoolers are absolutely critical for thermal management and must receive adequate cooling water flow at all times. 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. A closed-loop cooling tower with side-stream filtration and chemical treatment is strongly recommended for all installations to ensure consistent water quality and prevent scale formation in the intercoolers.
Preventive Maintenance Schedule
| Interval | Service Item | Action Required |
|---|---|---|
| Daily | Operational Inspection | Check vibration, abnormal noise, cooling water flow, discharge pressure/temperature at all stages |
| 250 hours | Valve Plate Inspection (All Stages) | Remove and inspect all suction/discharge valves for carbon deposits, spring fatigue, cracking |
| 1,000 hours | Piston Ring Wear Assessment (All Stages) | Measure groove clearance at all stages; replace rings if clearance exceeds 0.18 mm |
| 2,500 hours | Intermediate Overhaul | Replace all piston rings, rider bands, and valve plate assemblies across all three stages |
| 5,000 hours | Major Overhaul | Inspect crankshaft journals, measure all bearing clearances, replace bearings if >0.06 mm |
The oil-free design of the 3ZW-6/30 dramatically simplifies maintenance compared to lubricated alternatives. There are no oil changes, no oil analysis, no filter replacements, and no separator cartridge changes. The primary consumable wear items are the PTFE piston rings and rider bands, which typically achieve 2,500–4,000 hours of service life under clean nitrogen conditions at ultra-high pressure. The high-pressure valve plates (particularly on the third stage) may require more frequent inspection than low-pressure equivalents due to the increased mechanical stress, but the overall maintenance burden remains significantly lower than oil-lubricated systems of equivalent pressure capability.
Compliance & Safety Certifications
The 3ZW-6/30 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. At 3.00 MPa discharge pressure, the risk of rapid gas release and oxygen displacement is extremely elevated. All 3ZW-6/30 installations must incorporate continuous oxygen deficiency monitoring in the compressor room and all adjacent areas. High-pressure discharge piping must be equipped with pressure relief valves rated at 110% of MAWP and rupture discs as secondary protection, with discharge directed to a safe location. All high-pressure piping must be designed, fabricated, and inspected in accordance with ASME B31.3 (Process Piping). Ventilation systems must maintain ambient oxygen above 19.5% per OSHA 29 CFR 1910.146. Emergency shutdown interlocks should activate at 19.5% O₂ (alarm) and trigger automatic isolation at 18.0% O₂ (hard shutdown). Personnel must be trained in ultra-high-pressure gas safety protocols and wear appropriate PPE before operating or maintaining this equipment. No personnel shall be present in the compressor room during pressure testing or initial startup.
Performance & Efficiency Analysis
The 3ZW-6/30 achieves a specific power consumption of approximately 12.50 kW per m³/min of nitrogen delivered at 3.00 MPa discharge pressure from atmospheric inlet. This specific power figure reflects the thermodynamic reality of ultra-high-pressure compression, where the work required increases substantially with pressure ratio. Within the ultra-high-pressure oil-free piston compressor segment (discharge pressure >2.50 MPa), this efficiency is competitive and significantly superior to diaphragm compressors, which are the primary alternative for oil-free ultra-high-pressure service. For comparison, oil-lubricated reciprocating compressors in similar ultra-high-pressure applications typically consume 13.0–15.0 kW/m³/min, while diaphragm compressors may exceed 18 kW/m³/min.
Over a standard 8,000-hour annual operating schedule, the 3ZW-6/30’s efficiency advantage versus less efficient alternatives yields approximately 72,000–144,000 kWh of annual energy savings. At $0.08/kWh, this represents $5,760–$11,520 in direct electricity cost reduction per year. However, the primary economic justification for the 3ZW-6/30 is typically the elimination of oil-related consumables and the avoidance of downstream oil-removal equipment that would be mandatory with lubricated alternatives at this pressure level. The total cost of ownership for ultra-high-pressure nitrogen compression is reduced by an estimated 30–45% over a 10-year operational life when oil-free operation is compared to lubricated systems with full downstream purification.
The absence of oil in the compression path is particularly valuable at ultra-high pressure because oil contamination becomes exponentially more concentrated and more difficult to remove as pressure increases. At 3.00 MPa, the partial pressure of oil vapor would be approximately 15 times higher than at 0.30 MPa, making downstream oil-filtration systems virtually ineffective and prohibitively expensive. The 3ZW-6/30’s native oil-free design eliminates this challenge entirely, ensuring that nitrogen purity is maintained regardless of operating pressure.
Customization & OEM Capabilities
We offer comprehensive customization options to adapt the 3ZW-6/30 to specific site conditions, integration requirements, and end-user specifications:
- Skid-Mounted Turnkey Packages: Pre-assembled compressor, motor, three intercoolers, aftercooler, high-pressure discharge piping, instrumentation, and control panel on a structural steel skid with integrated lifting lugs and anchor bolt templates. Factory pre-testing of all systems reduces commissioning time by 70%.
- Hazardous Area Configurations: ATEX Zone 2 and IECEx compliant motor and electrical enclosures for petrochemical installations. Integrated gas detection, automatic ventilation interlocks, and explosion-proof instrumentation.
- 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 stage-by-stage pressure monitoring and alarm systems. High-pressure safety interlocks including automatic unload on overpressure and emergency isolation valves on all stages.
- Environmental Protection: C5-M marine-grade coatings for coastal installations; tropicalized electrical components for 55°C ambient; IP54-rated acoustic enclosures reducing noise from 85 dB(A) to 72 dB(A) at 1 meter.
- OEM & Private Label: Custom paint colors, branded nameplates, and localized documentation packages for gas equipment distributors and system integrators.
Custom configurations are available from MOQ 1 unit. Engineering review and proposal generation typically require 5–7 business days. Standard delivery time is 12–14 weeks; repeat orders are delivered in 8–10 weeks from order confirmation.
Case Study: Chemical Synthesis Plant Nitrogen Injection Upgrade
Client: A specialty chemical manufacturer in Indonesia operating high-pressure batch reactors for polymer production
Challenge: The plant required ultra-high-pressure nitrogen (2.80–3.00 MPa) for reactor inerting and catalyst bed preservation during batch polymerization cycles. Their existing oil-lubricated compressor (imported European brand, 12 years in service) was experiencing severe oil carryover into the nitrogen stream, with contamination levels reaching 5.2 mg/m³. This oil contamination was poisoning the Ziegler-Natta polymerization catalyst, reducing catalyst efficiency by 30% and causing off-specification polymer batches. The oil was also fouling the reactor heat transfer surfaces, requiring quarterly chemical cleaning. Annual maintenance costs had escalated to $65,000.
Solution: We supplied a 3ZW-6/30 oil-free nitrogen compressor as the primary high-pressure nitrogen source, configured on a custom skid with three integrated intercoolers, aftercooler, and a Siemens S7-1200 PLC control panel with stage-by-stage pressure monitoring. The 3.00 MPa discharge pressure met the reactor inerting requirements with a safety margin. The oil-free design eliminated catalyst poisoning and reactor fouling. A 2 m³ surge vessel was installed upstream to buffer demand fluctuations from the batch reactor cycle.
Quantified Results After 18 Months:
- Nitrogen oil content: Reduced from 5.2 mg/m³ to <0.01 mg/m³, achieving ISO 8573-1 Class 0
- Catalyst efficiency: Restored to 95% (from 65%), reducing catalyst consumption by 32%
- Off-specification batches: Eliminated completely, saving $45,000/year in rework costs
- Reactor cleaning frequency: Reduced from quarterly to annually, saving $18,000/year
- Annual maintenance cost: Reduced by 48% ($65,000 to $33,800)
- Payback period: 1.6 years based on catalyst savings, rework elimination, and maintenance reduction
“The 3ZW-6/30 has transformed our polymerization process. The elimination of oil contamination has restored our catalyst performance to design levels and eliminated our off-spec batch problem. Our maintenance team now spends their time on preventive activities rather than emergency oil-related repairs. The payback was faster than our finance team projected.” — Production Director, Specialty Chemical Plant
FAQ & Selection Guide
Related Products & Solutions
DW Series High-Pressure Nitrogen Compressors
Designed for discharge pressures from 0.40 MPa to 2.00 MPa, the DW series covers nitrogen injection, high-pressure pipeline boosting, and chemical synthesis. Capacities from 2 to 130 m³/min.
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 ultra-high-pressure gas filling and chemical process applications.
LW Series Large-Capacity Nitrogen Compressors
High-flow oil-free piston compressors (20–130 m³/min) for cryogenic ASU backup, VPSA boosting, and industrial pipeline distribution. Discharge pressures from 0.30 to 0.80 MPa.
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 Upgrade Your Ultra-High-Pressure Nitrogen 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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