Description
Z Series High Pressure Natural Gas Compression — Small-Volume Multi-Stage Reciprocating Process Service
The Z Series high pressure natural gas compressor handles small gas volumes at comparatively high discharge pressures. Three verified models cover capacities from 2 to 5.5 m³/min at discharge pressures from 2.40 to 6.00 MPa, using multi-stage reciprocating compression. The highest confirmed discharge pressure in this series — 6.00 MPa, on the ZW-2/60 — is the highest of any Z Series model in either the low-pressure or high-pressure product families.
All three models draw from a 380 V electrical supply, which is consistent with the relatively low motor power required at these small gas volumes — 45 to 75 kW. This combination of high discharge pressure and low motor power is characteristic of high-compression-ratio applications where the gas volume handled is small but the pressure increase required is substantial. All three models are available in modular (机组化) configurations, which can simplify transport and installation for remote or constrained sites.
Operating Range
Discharge Pressure Range (verified models): 2.40 – 6.00 MPa
Capacity Range (verified models): 2 – 5.5 m³/min
Stage Configuration: Two-row three-stage (ZW-4/25, ZW-2/60); three-row three-stage (ZW-5.5/24)
Driver Power Range: 45 – 75 kW
Electrical Supply: 380 V
Capacity values are in m³/min as stated in source data. Flow-reference basis must be confirmed for North American sizing. Pressure values as stated; pressure basis (gauge/absolute) should be verified for engineering use.
Available Models and Technical Specifications
| Model | Configuration | Capacity (m³/min) | Discharge Pressure (MPa) | Dimensions L×W×H (mm) | Weight (t) | Power (kW) | Voltage |
|---|---|---|---|---|---|---|---|
| ZW-5.5/24 | 3-row, 3-stage | 5.5 | 2.40 | 1889×1900×2720 | 3.50 | 75 | 380 |
| ZW-4/25 (modular) | 2-row, 3-stage | 4 | 2.50 | 1920×1900×2580 | 3.97 | 55 | 380 |
| ZW-2/60 (modular) | 2-row, 3-stage | 2 | 6.00 | 1550×1710×1520 | 2.90 | 45 | 380 |
Capacity in m³/min as stated in source data; flow-reference basis must be confirmed. ZW-4/25 and ZW-2/60 are listed as modular configurations (机组化) in the source. Pressure as stated; gauge/absolute basis should be verified before engineering use.
High Pressure Ratio at Small Gas Volume — Engineering Considerations
The Z Series high-pressure models compress gas from a suction condition to discharge pressures that, at near-atmospheric suction, represent overall compression ratios in the range of approximately 16:1 (at 1.6 MPa absolute discharge) to more than 40:1 (at 6.0 MPa absolute discharge), depending on the suction pressure. These are high pressure ratios, and three-stage compression is the appropriate configuration to distribute them into manageable per-stage values.
In a three-stage arrangement, the overall ratio is divided across three compression steps. For example, at a 6.0 MPa discharge and atmospheric suction, three stages each handling a partial ratio of roughly 3.4:1 to 4:1 can achieve the overall ratio through successive compression steps, with interstage cooling between each stage to control the temperature entering the next cylinder. Without this division, single- or two-stage compression at these ratios would produce discharge temperatures that exceed safe limits for cylinder valves and seals.
The ZW-5.5/24 uses a three-row configuration for its three stages, assigning one stage per row. The ZW-4/25 and ZW-2/60 achieve three compression stages within a two-row frame — an arrangement that requires two compression stages on one row and a single stage on the other, or cylinders arranged in tandem. The actual cylinder arrangement within the frame should be confirmed with the engineering team for detailed piping and installation planning.
The ZW-2/60 at 6.00 MPa
The ZW-2/60 delivers 2 m³/min at a discharge pressure of 6.00 MPa — the highest verified discharge pressure across all Z Series models. At 45 kW and 380 V, this machine compresses a small gas volume to a pressure level that requires careful engineering of the compression stages, interstage cooling, cylinder materials, valve design, and piston seal selection. Despite the small gas volume, 6.00 MPa represents a demanding mechanical duty that influences the entire machine design.
The modular designation on the ZW-2/60 (and ZW-4/25) suggests these units can be configured for simplified transport and site assembly, which is relevant for remote or access-constrained installations where delivering a large pre-assembled unit would be impractical. The engineering team should be consulted on what “modular configuration” means in terms of the specific split points in the machine assembly for the project site.
Applications for Small-Capacity High-Pressure Compression
At 2 to 5.5 m³/min and 2.40 to 6.00 MPa, the Z Series high-pressure range suits applications where the gas volume is inherently small but the required delivery pressure is substantial. Natural gas boosting from a low-pressure source to a high-pressure process or pipeline — where the volume is limited by the source or by the scale of the receiving process — is a potential application. Gas transfer between pressure vessels at different pressure levels, where the volume transferred is small, may also fall within this range.
Process gas duties in small-scale industrial installations — where a limited amount of natural gas must be compressed to a high pressure for a specific process step — represent another category of application. In all cases, suction pressure must be provided to accurately evaluate the actual compression ratio and confirm the appropriate machine configuration.
Information Required for Compressor Selection
- Gas composition (full component breakdown)
- Methane, CO₂, and H₂S content
- Suction pressure and suction temperature
- Required discharge pressure
- Required flow rate and flow-reference basis
- Site ambient temperature and altitude
- Continuous or intermittent duty
- Available electrical supply (voltage and frequency)
- Cooling method preference (air-cooled or water-cooled)
- Hazardous-area classification requirements
- Modular or skid-mounted package requirements
- Destination country and project location
Frequently Asked Questions
How does the ZW-2/60 achieve 6.00 MPa at only 45 kW?
The relatively low motor power reflects the very small gas volume — 2 m³/min — rather than the discharge pressure alone. Compression power is proportional to both the mass flow rate and the work of compression per unit mass. At 2 m³/min, the total mass flow is small, and the absolute work performed on the gas is modest even at high pressure. The mechanical design at 6.00 MPa still requires robust high-pressure cylinder construction and careful valve and seal selection, but the drive power requirement is determined by the product of flow rate and compression work, not by discharge pressure alone.
What is the difference between the ZW-5.5/24 three-row configuration and the ZW-4/25 two-row configuration?
Both models use three compression stages. The ZW-5.5/24 distributes these three stages across three cylinder rows. The ZW-4/25 achieves three stages within a two-row frame, which requires a different internal arrangement of cylinders within the frame. The outer dimensions and weights are similar (approximately 1,889–1,920 mm length, 1,900 mm width, 3.50–3.97 tonnes), but the internal configuration differs. The engineering team can provide details on the cylinder arrangement for specific installation and piping planning.
Is the Z Series appropriate for sour gas service?
H₂S and CO₂ content in the gas must be disclosed at the inquiry stage for any high-pressure compressor. Elevated H₂S concentrations present corrosion risks to cylinder bores, piston rods, packing, valves, and associated piping — especially at higher discharge pressures where the partial pressure of H₂S increases. The engineering team will evaluate the gas composition and advise on whether standard materials are suitable or whether upgraded materials and seal configurations are required. Do not assume sour gas suitability without explicit technical review.
Request a Technical Proposal
Small-volume high-pressure gas compression requires careful matching of the stage configuration to the actual suction and discharge conditions. To evaluate Z Series high-pressure models for your application, the engineering team needs gas composition, suction pressure and temperature, target discharge pressure, required flow rate and its reference basis, electrical supply details, and any modular package or site access constraints. These inputs allow the team to confirm the stage arrangement, cylinder specification, and interstage cooling design before preparing a technical proposal.
Related Compressor Products
- L Series High Pressure Natural Gas Compressor — two-stage and three-stage, 6–25 m³/min at 1.80–3.60 MPa
- D Series High Pressure Natural Gas Compressor — medium-capacity multi-stage high-pressure service
- Z Series Low Pressure Natural Gas Compressor — Z Series at low pressure, 6 m³/min at 0.80 MPa
- Natural Gas Compressor — full product line overview
