Ultra-low pressure in. CNG fill pressure out. One package.
The 4-stage NuPresto 400 takes natural gas from suction pressures as low as 40 psig all the way to CNG fill pressure in a single skid. Built for declining wells, low-pressure RNG and gathering systems where standard 2- and 3-stage packages cannot reach.
Overview
The 4-stage NuPresto 400 is engineered for the lowest end of the suction window, 40 to 100 psig, where two or three stages of compression cannot deliver the ratio needed to land at 4,200 psig CNG discharge. Four compression stages, four intercooler sections and a final aftercooler keep stage temperatures and ratios inside the design envelope across the full operating range.
Mechanically it is the same NuPresto 400 platform: Fornovo Gas DA300 frame, non-lubricated water-cooled cylinders, PLC controls and full FAT in shop.
Key specifications
| Compression stages | 4-stage |
|---|---|
| Compressor frame | Fornovo Gas DA300 heavy-duty reciprocating |
| Cylinders | Non-lubricated, water-cooled, with HP valves |
| Suction pressure | 40 to 100 psig |
| Discharge pressure | Up to 4,200 psig |
| Flow rate | Up to 1.1 MMSCFD |
| Driver | 200 to 350 HP electric motor (depends on suction pressure), 1,200 rpm |
| Interstage cooling | 4-section air cooler plus jacket water circuit |
| Discharge treatment | Interstage scrubbers and final discharge coalescer |
| Cooling package | Closed-loop glycol with multi-fan air cooler |
| Control system | PLC-based with HMI, remote monitoring via Ewon |
| Lube oil | Chevron Cetus PAO 68 or approved equivalent, shaft-driven lube oil pump |
| Design standards | ASME Section VIII Div. 1, B31.3, NEC, NFPA, API and ISO |
| Skid | Single skid, fully assembled and FAT-tested in shop |
Detailed performance curves are not published; contact engineering for sized performance.
NuPresto 400 family at a glance
| Variant | Suction | Flow | Best fit |
|---|---|---|---|
| 2-Stage | 550 to 900 psig | Up to 3.64 MMSCFD | High-pressure pipeline mother stations |
| 3-Stage | 150 to 600 psig | Up to 2.6 MMSCFD | RNG and low to mid-pressure pipeline service |
| 4-Stage | 40 to 100 psig | Up to 1.1 MMSCFD | Declining wells, low-pressure RNG, stranded gas |
Why NuPresto 400 4-Stage
Built for the lowest suction pressures
Declining gas wells, low-pressure RNG dryer outlets and aging gathering systems often deliver gas below 100 psig. The 4-stage NuPresto 400 handles that inlet directly. No separate booster, no field-built workaround.
Four-section air cooler
Engineered air cooler with separate sections for each stage discharge plus jacket water. Stage temperatures stay inside the design window even at 100 °F ambient and 3,000 ft elevation.
Same frame, same controls, same service plan
Identical Fornovo DA300 bottom end, control philosophy, HMI and remote monitoring as the 2- and 3-stage. Same maintenance intervals, same spares. Operators trained on one variant are trained on all three.
Non-lubricated cylinders
No oil carryover into the gas stream. Cleaner downstream equipment, less environmental risk, simpler permitting.
Engineered for continuous service
Interstage scrubbers, pulsation control and ASME-stamped vessels and coolers sized for 24/7 wellhead, RNG and CNG mother station duty.
Built and tested in shop
Final assembly, FAT, loop checks and HMI commissioning happen in our shop. Issues get caught in the shop, not on your site.
Typical applications
- Declining gas well compression with CNG offtake
- Low-pressure RNG-to-CNG mother stations
- Aging gathering systems and stripper well consolidation
- Pad gas and casinghead gas capture
- Virtual pipeline trailer filling from very low-pressure sources
- Stranded gas monetization where pipeline access is limited
What's included
- Single skid with 4-stage compressor, motor, multi-section air cooler and process piping
- Inlet filter, four interstage scrubbers and final discharge coalescer
- Closed-loop glycol cooling system with jacket water circuit
- PLC, HMI and field instrumentation, wired and tested
- Cause-and-effect diagram, control narrative and FAT package
- ASME-stamped pressure vessels and coolers, B31.3 piping
- Installation, commissioning and start-up procedure
- Recommended spare parts list and pricing
Engineering and aftermarket support
Every 4-stage NuPresto 400 ships with a complete engineering package: P&IDs, GA drawings, electrical load lists, lifting and torsional analyses and a full O&M manual. Critical spares, including complete cylinders, are stocked at our shop for fast response.
Field service, troubleshooting and remote diagnostics are handled by the same team that designed and built the unit.