High-Speed Rotating Machinery
Engineered for Emissions
E4's technology portfolio is built on a foundation of ultra-high-speed centrifugal machinery, porous media gas sealing, and advanced heat exchange — enabling novel solutions to compression industry emissions challenges.
Four Enabling Technologies
E4's product innovations are built on four core technology platforms, each individually patented or patent-pending.
Ultra-High-Speed Centrifugal Separation
Rotary separators operating at 10,000–20,000+ RPM generate centrifugal forces orders of magnitude greater than gravity-based separation — enabling sub-micron liquid removal, cryogenic CO₂ separation, and efficient multi-phase processing in a compact footprint.
Porous Media Gas Film Sealing
Gas injected through porous media creates a controlled gas film boundary layer between moving components. Applied to rod packing and piston seals, this eliminates process gas contact with the atmosphere entirely — without mechanical contact or wear surfaces.
Moving Wall Compressor / Expander
Patented ultra-high-speed positive displacement rotary technology delivers very high power density with increased efficiency vs. existing technology. Serves as the compressor and expander core of the Exhaust Carbon Capture system and as a standalone high-performance compression module.
3D-Printed Lattice Heat Exchange
Custom lattice-optimized heat exchangers 3D-printed for high-temperature and cryogenic service increase thermal power exchange by more than 85% in a compact form. Sized based on exhaust flow rate and temperature — a key enabler of the ECC system's CO₂ capture efficiency.
Supersonic Isentropic Expansion
Gas accelerated through designed nozzles undergoes isentropic expansion at supersonic speeds, dropping temperature into the phase envelope for in-stream condensation and nucleation. Applied to fuel stabilization and cryo separation without external refrigeration requirements.
Supercritical CO₂ Processing
The ECC centrifugal separator operates at conditions producing supercritical CO₂ — discharged at 1,100–5,000 psi without added compression. The Moving Wall Compressor on the same rotating shaft handles compression, enabling a fully integrated, single-shaft CO₂ capture train.
ECC System Architecture
The Exhaust Carbon Capture (ECC) skid is designed to match the physical footprint of a medium compressor package (8' × 25') while handling the full exhaust stream of a 15,000 HP compressor station.
All major high-speed components are mounted on a single rotating shaft — eliminating gearboxes, couplings, and the associated maintenance complexity. The system also generates electrical power from waste heat via an integrated motor-generator, enabling net energy recovery from exhaust that currently goes to atmosphere.
Beyond CO₂, the system captures SOx, NOx, CO, and methane slip — separating and releasing each as discrete product streams. The result is a compressor station that operates with a near-zero carbon footprint on the compression side.
| Parameter | 8,000 HP Pilot | 15,000 HP Station |
|---|---|---|
| Exhaust Capacity | ~37M CF/Day | 70M CF/Day |
| CO₂ Extraction | ~40K Tons/Year | 75,000 Tons/Year |
| CO₂ Discharge Pressure | 1,100 – 5,000 PSI (Supercritical) | |
| CO₂ Separation Efficiency | >99% | |
| Skid Size | 8' × 25' | |
| Power Generation | Waste Heat Recovery via Motor-Generator | |
| Chemicals Required | None | |
ECC Process Flow
Exhaust Gas Inlet
Engine exhaust enters — piped similarly to waste heat recovery installations.
Lattice Heat Exchanger
3D-printed high-temp/cryo heat exchanger cools exhaust stream 85%+ more efficiently than conventional exchangers.
Centrifugal Cryo Separator
Ultra-high-speed (10–20K RPM) separator separates 99%+ CO₂ from exhaust at supercritical conditions.
Moving Wall Compressor
Single-shaft compressor raises CO₂ to 1,100–5,000 PSI supercritical discharge — no added compression step.
Rotary Separator (SOx/NOx/CO/CH₄)
Secondary separator captures remaining pollutant streams for separate product recovery.
Motor-Generator Power Recovery
Waste heat drives integrated generator — producing net electrical output from captured energy.
- ✓ System design complete — patent awarded April 2023
- ✓ CO₂ process modeling complete
- ✓ Test skid manufacturing design complete
- ✓ Pilot skid design complete — full working system
- → Field pilot with National Fuel Gas in development
- → Component testing ready to begin (Innio/Waukesha)
Moving Wall Technology Advantages
Two separate patents granted — one for the Moving Wall Compressor, one for the Moving Wall Expander. Both are integral components of the ECC system single-shaft rotating assembly.
Positive Displacement at Rotary Speed
The Moving Wall Compressor and Expander represent a fundamental advance in positive displacement rotary machinery. By operating at ultra-high speeds, the Moving Wall technology achieves very high power density in a small package — making it suitable for integration into the ECC skid where physical space is constrained.
As both compressor and expander, Moving Wall components serve dual roles in the ECC system: the compressor raises captured CO₂ to supercritical discharge pressure, while the expander recovers energy from the high-pressure gas stream to drive the rotating shaft — reducing net power consumption of the capture system.
Both the compressor and expander variants are independently patented, with commercial applications extending beyond the ECC system into standalone high-efficiency compression markets.
Patent Portfolio
E4's technology innovations are protected by granted patents and multiple pending applications.
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Exhaust Carbon Capture System
Granted — April 2023Full system patent covering the centrifugal cryogenic CO₂ capture skid, including the single-shaft rotating assembly, 3D lattice heat exchanger integration, and supercritical CO₂ discharge train.
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Moving Wall Compressor
GrantedPatent covering the ultra-high-speed positive displacement rotary compressor configuration and operating principles of the Moving Wall mechanism.
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Moving Wall Expander
GrantedSeparate patent covering the expander configuration of Moving Wall technology, enabling energy recovery from high-pressure gas streams within the ECC rotating assembly.
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Zero Methane Rod Packing
Patent PendingPatent application covering the externally pressurized dry gas porous media rod packing system that eliminates fugitive methane emissions from reciprocating compressor packing cases.
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Oil-Free Piston Seals
Patent PendingPatent application covering the porous media piston assembly gas film sealing technology that eliminates oil lubrication requirements in reciprocating compressor cylinders.