Description
4M Series Low Pressure Natural Gas Compression — Four-Row Two-Stage Industrial Reciprocating Compressor
The 4M Series low pressure natural gas compressor uses a four-row two-stage reciprocating configuration to deliver 180 to 240 m³/min at a discharge pressure of 0.65 MPa. Two verified models are available. The four-row mechanical layout and two-stage compression arrangement distinguish this series from the two-row machines that make up the majority of the low-pressure product family.
Within the low-pressure product line, the 4M Series occupies a defined position: higher discharge pressure than the D and H Series single-stage models, and substantially higher gas capacity than the small-unit end of the range. The 0.65 MPa discharge pressure, combined with the high gas flow, represents a process duty that requires a purpose-designed multi-row machine to manage both the cylinder displacement and the two-stage compression arrangement within a single frame.
Operating Range and Configuration
Discharge Pressure: 0.65 MPa (both verified models)
Capacity Range: 180 – 240 m³/min
Configuration: Four-row, two-stage
Driver Power Range: 1,000 – 1,300 kW
Electrical Supply: 6 kV or 10 kV
Flow capacity is expressed in m³/min as stated in the source data. The flow-reference condition must be confirmed with the engineering team before applying these values to North American compressor sizing.
Available Models and Technical Specifications
| Model | Configuration | Capacity (m³/min) | Discharge Pressure (MPa) | Dimensions L×W×H (mm) | Weight (t) | Power (kW) | Voltage |
|---|---|---|---|---|---|---|---|
| 4MW-180/6.5 | 4-row, 2-stage | 180 | 0.65 | 6250×3905×3020 | 26.00 | 1000 | 6K or 10K |
| 4MW-240/6.5 | 4-row, 2-stage | 240 | 0.65 | 6250×3905×3020 | 26.00 | 1300 | 6K or 10K |
Both models share identical frame dimensions and weight (26.00 t), with capacity and power as the differentiating parameters. Capacity expressed in m³/min; flow-reference basis must be confirmed. Pressure as stated in source data; gauge/absolute basis should be verified before engineering use.
Four-Row Layout and Why Two Stages at 0.65 MPa
The four-row frame provides four cylinder banks, two on each side of the crankshaft. This allows the machine to handle the large total piston displacement needed for 180 to 240 m³/min while distributing the mechanical load across four banks rather than two. The wide, square footprint — approximately 3,905 mm wide versus 3,640 mm for the largest D Series unit — reflects this multi-row construction.
At 0.65 MPa discharge pressure with a near-atmospheric suction, the absolute compression ratio is sufficient to justify two-stage compression. When the total pressure ratio is divided between two stages, each stage handles a lower individual ratio, which reduces the temperature rise across each cylinder and keeps discharge temperatures within limits acceptable for cylinder valves, piston rings, and the gas itself. For a natural gas stream, high discharge temperature can also raise the risk of carbonization on valve surfaces — a two-stage arrangement helps control this at the discharge pressures involved.
Between the first and second compression stage, an interstage cooler typically reduces the gas temperature before it enters the second-stage cylinder. Cooling method — air-cooled or water-cooled — affects the cooler design and the temperature achievable at the second-stage inlet. This in turn affects second-stage cylinder performance and overall machine efficiency. The engineering team will specify the interstage cooling arrangement based on the site’s cooling-medium availability and ambient conditions.
High-Voltage Supply and Physical Scale
At 1,000 to 1,300 kW, both 4M Series low-pressure models require a 6 kV or 10 kV electrical supply. This is consistent with the large D Series and H Series models in the low-pressure family and reflects the industrial scale of the machine. Site electrical planning should include transformer sizing, switchgear, and cabling capable of handling the full-load motor current at the relevant voltage level.
The two models share the same frame dimensions (6,250 × 3,905 × 3,020 mm) and the same 26-tonne weight, which simplifies foundation engineering when selecting between the two capacity options. The higher-capacity 4MW-240/6.5 draws 1,300 kW versus 1,000 kW for the 4MW-180/6.5, but the mechanical frame and foundation requirements are identical.
Process Applications
The 4M Series low-pressure configuration targets process duties requiring high gas volume at a moderate pressure above atmospheric — gathering and concentrating gas from multiple sources at 0.65 MPa delivery pressure, or moving large volumes of process gas within a gas treatment plant from one process section to another at this pressure level. The 180 to 240 m³/min capacity range places this series well above typical single-well or small-pad compression requirements and into the range of centralized processing or midstream compression facilities.
Industrial gas handling applications — where natural gas or process gas must be handled at controlled moderate pressure for combustion, chemical process, or fuel-gas supply — may also suit the 4M Series capacity range, depending on the specific pressure and flow conditions involved.
Comparing the 4M Series with Adjacent Low-Pressure Options
At 180 to 240 m³/min and 0.65 MPa, the 4M Series fills a position in the low-pressure range that neither the D Series nor the H Series occupies at the same pressure level. The D Series reaches 0.60 MPa with two-row two-stage machines at capacities up to 116 m³/min. The H Series achieves much higher volumes — up to 600 m³/min — but at lower discharge pressures of 0.10 to 0.25 MPa in a single-stage arrangement. The 4M Series provides the combination of higher volume than the D Series at 0.60 MPa and higher discharge pressure than the H Series at comparable volumes, using the four-row two-stage design to achieve this combination.
Information Required for Compressor Selection
- Gas composition (full component breakdown)
- Methane, CO₂, and H₂S content
- Suction pressure and suction temperature
- Required discharge pressure
- Required gas flow rate and flow-reference basis
- Site ambient temperature range and altitude
- Continuous or intermittent duty cycle
- Available electrical supply voltage and frequency
- Cooling method availability (air-cooled or water-cooled)
- Hazardous-area classification requirements
- Skid and package requirements
- Destination country and project site location
Frequently Asked Questions
Why do both 4M low-pressure models have the same frame dimensions but different capacities?
The two models share the same mechanical frame, which defines the outer dimensions and weight. Capacity differences between the two models result from differences in cylinder bore, stroke, or operating speed within the same frame envelope. This is a common approach in reciprocating compressor design: a proven frame is used across a range of cylinder configurations to optimize manufacturing costs while providing capacity options within a standard package footprint.
Is the 0.65 MPa discharge pressure a gauge or absolute value?
The discharge pressure values in the source data are presented without explicit designation of gauge or absolute basis. For engineering and sizing purposes, the gauge or absolute basis must be confirmed with the engineering team. In North American practice, compressor discharge pressures are typically stated in psig (pounds per square inch gauge), so the conversion and pressure basis should be clarified before using these values in project specifications.
Can the 4M Series handle gas with liquid content in the suction stream?
Reciprocating compressors are not designed to ingest liquids. If the gas stream entering the 4M Series contains entrained liquid water, hydrocarbon condensate, or other liquid phases, appropriate suction knockout vessels or scrubbers must be installed upstream of the compressor suction nozzle. The engineering team should review the expected gas composition, temperature, and pressure at the suction point to determine the liquid-separation requirements for the specific application.
Request a Technical Proposal
To assess the 4M Series for your process, the engineering team needs gas composition, suction pressure and temperature, required discharge pressure, required gas flow rate with the flow-reference basis, electrical supply details, and site conditions including ambient temperature, altitude, and cooling-medium availability. These parameters allow the team to confirm model selection, stage configuration, motor specification, and package design before preparing a technical proposal covering equipment scope, dimensions, and delivery schedule.
Related Compressor Products
- H Series Low Pressure Natural Gas Compressor — four-row one-stage, capacities up to 600 m³/min at lower discharge pressures
- D Series Low Pressure Natural Gas Compressor — two-row models from 60 to 325 m³/min at 0.10–0.60 MPa
- 4M Series High Pressure Natural Gas Compressor — four-row four-stage configuration for high-pressure process service
- Natural Gas Compressor — full product line overview
