Biogas Upgrading Membrane Separation — PatSnap Eureka
Biogas Upgrading Membrane Separation Patents 2026
Membrane separation has emerged as the dominant technology for converting raw biogas into pipeline-quality biomethane. This dataset spans filings from 2012 to 2026 across polymeric, carbon, MOF, and hybrid membrane architectures.
From Raw Biogas to Pipeline-Grade Biomethane
Raw biogas from anaerobic digestion typically contains 50–70% CH₄ and 30–50% CO₂ and must be upgraded to ≥95% CH₄ purity for most commercial applications. Membrane separation selectively permeates CO₂ through semi-permeable membranes, leaving a methane-enriched retentate suitable for grid injection, vehicle fuel, or liquefaction into biomethane (LBM).
Dominant membrane materials in this dataset include polymeric hollow fiber membranes (polyimide, polysulfone, cellulose acetate), carbon hollow fiber (CHF) membranes achieving CO₂/CH₄ selectivities exceeding 246, MOF-based membranes, nano-engineered grazynes with selectivities up to 39, and mixed-matrix thin-film composites integrating inorganic fillers for enhanced performance.
Core sub-domains identified include single- and multi-stage polymeric membrane systems, hybrid PTSA/membrane systems, membrane bioreactors combining physical separation with biological methanation, CO₂ permeate recycling to anaerobic digesters, and integration with liquefaction for liquefied biomethane (LBM) production.
Innovation in this dataset is moderately concentrated in three major industrial gas companies — Air Products, Air Liquide, and Iogen — with emerging activity from smaller specialized players including Unconventional Gas Solutions and Airrane, and academic institutions such as Syddansk Universitet and Paul Scherrer Institut, in retrieved records.
Filing Trends and Technology Cluster Distribution
Patent activity in this dataset spans four identified technology clusters and multiple jurisdictions, with clear acceleration in multi-stage polymeric systems and emerging filings in carbon capture integration and ultra-high purity RNG from 2024 to 2026.
Patent Filings by Technology Cluster (Dataset Snapshot)
Multi-stage polymeric hollow fiber membrane systems account for the largest share of filings in this dataset, followed by hybrid PTSA/membrane systems and natural gas sweep architectures.
↗ Click bars to exploreFiling Activity by Period in Retrieved Records
Filings in this dataset accelerated markedly in the 2021–2026 period, with the most recent phase (2024–2026) contributing the highest volume of emerging-direction patents including CCU integration and ultra-high-purity RNG.
↗ Click bars to exploreDeployment Zones and Use Cases in This Dataset
Membrane-based biogas upgrading addresses six identified application domains in this dataset, ranging from grid injection of pipeline-grade biomethane to Power-to-X integration and carbon capture coupling, with named sites and institutions grounding each domain.
Distributed RNG Grid Injection (US)
Iogen Corporation’s US patents (2018–2020) describe distributed pre-purification of biogas from multiple agricultural and waste sources followed by centralized membrane upgrading and grid injection. L’Air Liquide’s 2024 US patent returns CO₂-rich permeate to the anaerobic digester to improve carbon efficiency of the grid injection chain. Unconventional Gas Solutions’ 2025–2026 US/EP filings target <50 ppm residual CO₂ and >99% methane recovery for premium RNG grid delivery.
Grid InjectionGlor IKS Plant, Lillehammer Norway
The Glor IKS plant in Lillehammer, Norway, processed 60 Nm³/h of food waste biogas to Swedish vehicle fuel standards in a single-stage carbon hollow fiber membrane system, as documented in field results published in 2018. Indian Oil Corporation’s US/EP patent (2021) targets bio-CNG via a biomimetic-hybrid solvent system. Air Liquide Advanced Technologies’ 2024 US patent addresses compressed natural gas production from raw biogas using membranes integrated within a multi-stage compression train.
Vehicle FuelLiquefied Biomethane Plants, Italy
Two Italian-origin patents from Negri Nicola (WO, 2025; IT, 2025) describe membrane upgrading as the front-end separation module for liquefied biomethane (LBM) production, with off-gas methane recovery to reduce carbon losses prior to liquefaction. These filings represent an emerging application segment integrating upgrading with downstream cryogenic liquefaction in the European context.
LBM ProductionPaul Scherrer Institut, Switzerland
Paul Scherrer Institut filed dual EP and WO patents in 2024 combining polymeric gas separation membranes with fluidized bed methanation reactors, targeting flexible part-load operation of biogas-based Power-to-X (PtX) systems. These patents address variable renewable energy grid integration challenges by enabling dynamic biomethane production rates. The filings directly respond to EU requirements for green gas in PtX value chains.
Power-to-XKey Patent Assignees in Biogas Membrane Upgrading (Retrieved Records)
In this dataset, three major industrial gas companies — Air Products and Chemicals, L’Air Liquide (including Air Liquide Advanced Technologies), and Iogen Corporation — account for the largest filing volumes in retrieved records, spanning US, EP, CA, WO, and IN jurisdictions across multi-stage polymeric, PTSA hybrid, and natural gas sweep architectures.
Top Assignees by Filing Count in Retrieved Records (Dataset Snapshot)
↗ Click bars to exploreL’Air Liquide (incl. Air Liquide Advanced Technologies)
L’Air Liquide and its subsidiary Air Liquide Advanced Technologies hold approximately 14 filings in this dataset spanning US, EP, WO, FR, and CA jurisdictions from 2018 to 2024. Technology areas include integrated PTSA/membrane systems for H₂S and CO₂ removal (2018 US/WO), multi-type membrane biomethane production (2020/2023 US), CNG production via compressor-integrated membranes (2024 US), CO₂ permeate recycle to pressurized digesters (2024 US), and two-stage biomethane plant configurations (2022/2024 US, 2024 EP/WO). Patents span both granted and pending status across jurisdictions.
France / United StatesIogen Corporation
Iogen Corporation holds approximately 12 filings in this dataset across US (×6), WO, CA (×3), and CN jurisdictions from 2018 to 2026. Key technology areas include the natural gas sweep concept (2018–2019 US), where natural gas withdrawn from the distribution grid at ≥50% of upgraded biogas volume is used as permeate sweep to eliminate methane loss, distributed pre-purification of agricultural and waste biogas (2020 US/WO), and the most recent 2025–2026 US/CA filings continuing the RNG grid injection portfolio. Patent status includes granted US patents and pending CA/CN filings.
Canada2024–2026 Innovation Signals in Membrane Biogas Upgrading
Filings dated 2024–2026 in this dataset reveal six directional signals: ultra-high purity RNG, CO₂ permeate recycling to pressurized digesters, 4-stage sweep processes, carbon capture integration, Power-to-X coupling, and membrane-VSA hybrid systems from India.
Ultra-High Purity RNG Below 50 ppm CO₂
Unconventional Gas Solutions’ multi-stage architecture (EP, 2026; multiple US counterparts, 2025) targets residual CO₂ below 50 ppm — far beyond standard biomethane specifications — enabling direct substitution for fossil natural gas in sensitive industrial applications. The three-stage system uses differentiated selectivity requirements: >40 for stages 1 and 3, and >20 for stage 2, achieving >99% methane recovery. This represents a step-change in RNG purity specifications beyond the conventional ≥95% CH₄ commercial threshold.
CO₂ Permeate Recycling to Pressurized Anaerobic Digesters
L’Air Liquide’s 2024 US patent introduces pressurized digesters operating above 4 bara, with CO₂-rich membrane permeate recycled back into the digester to enable in-situ biological CO₂ utilization. This couples membrane separation efficiency with enhanced carbon conversion within the digestion stage itself, reducing net CO₂ emissions from the upgrading chain. The approach is distinct from conventional permeate venting or CO₂ recovery by treating the permeate as a co-substrate for methanogenesis.
Polymeric vs. Carbon Hollow Fiber Membranes for Biogas Upgrading
Click any row to explore further.
| Dimension | Polymeric Hollow Fiber Membranes | Carbon Hollow Fiber (CHF) Membranes |
|---|---|---|
| CO₂/CH₄ Selectivity | Typically 30–50 for commercial polyimide membranes | Up to 246 for post-oxidized/reduced (PORCHF) membranes |
| CO₂ Permeance | Higher permeance at moderate selectivity (commercial benchmark) | 0.021 m³(STP)/m²·h·bar demonstrated for PORCHF |
| Commercial Maturity | Commercially deployed; studied in Air Products PRISM PA1020 and UBE UMS-A5 modules achieving ≥96% CH₄ | Pilot-scale demonstrated at Glor IKS plant, Lillehammer, Norway (60 Nm³/h, 2018) |
| Materials | Polyimide, polysulfone, cellulose acetate, polyamide, polybenzoxazole, PIM | Post-oxidation and reduction (PORCHF) carbon derived from polymeric precursors |
| Patent Activity (Dataset) | Largest share of filings in this dataset from Air Products, Air Liquide, Iogen, Unconventional Gas Solutions | No major corporate assignee biogas-specific CHF patent identified in this dataset |
| Operating Pressure | 5–21 bar feed pressure documented in multi-stage system patents | N/A (pilot conditions not specified in retrieved records) |
| Multi-Contaminant Handling | PTSA pretreatment for H₂S, water, VOCs upstream of membrane; selectivity ≥10 for H₂S/CH₄ in first stage | Not addressed in retrieved literature for CHF biogas-specific configurations |
| Strategic IP Assessment | Dense IP thickets in multi-stage and PTSA hybrid architectures require design-around for new entrants | IP space remains more open; signals an opportunity for organizations capable of scaling CHF fabrication |
Frequently Asked Questions: Biogas Upgrading Membrane Separation
Most commercial applications require ≥95% CH₄ purity for pipeline injection. The most recent ultra-high-purity RNG systems, such as those patented by Unconventional Gas Solutions (2025–2026), target residual CO₂ below 50 ppm, enabling direct substitution for fossil natural gas in sensitive industrial applications.
Iogen Corporation’s patents (2018–2019 US) describe withdrawing natural gas from the distribution grid and using it as a sweep gas on the permeate side of the membrane. CO₂ permeating through the membrane is diluted into this sweep stream and returned to the grid as a CO₂-enriched natural gas blend rather than being vented, improving overall methane recovery economics. Iogen specifies that the natural gas volume withdrawn must be ≥50% of the upgraded biogas volume delivered to the grid.
Post-oxidized and reduced carbon hollow fiber (PORCHF) membranes have demonstrated CO₂/CH₄ selectivities of 246 and CO₂ permeance of 0.021 m³(STP)/m²·h·bar, far beyond typical commercial polyimide membranes at 30–50 selectivity. Despite this performance advantage, no major corporate assignee has filed CHF-specific biogas patents in this dataset, suggesting the IP space remains more open than polymeric membrane architectures.
A PTSA (pressure-temperature swing adsorption)/membrane hybrid system combines upstream PTSA beds selective for H₂S, water, and volatile organic compounds with downstream membrane stages for CO₂ separation. The PTSA unit removes contaminants that would degrade membrane performance, enabling the membrane to operate on a cleaner feed. Air Liquide Advanced Technologies filed this approach in 2018 (US/WO), with the first-stage PTSA followed by two-stage CO₂/O₂-selective membranes.
The United States is the single most represented jurisdiction in this dataset, hosting filings from all major assignees. The European Patent Office (EP) is the second most active, reflecting EU regulatory drivers including biomethane grid injection mandates and RED II targets. Canada is significant due to Iogen Corporation’s origin and Air Liquide/Air Products filings. India is an emerging jurisdiction with 2024–2026 filings from Air Products, Indian Oil Corporation, Sarvesh Sindhu, and Thermax Limited, reflecting India’s bio-CNG policy push.
L’Air Liquide’s 2024 US patent introduces pressurized anaerobic digesters operating above 4 bara with CO₂-rich membrane permeate recycled back into the digester. This enables in-situ biological CO₂ utilization within the digestion stage, improving carbon efficiency by treating the membrane permeate as a co-substrate for methanogenesis rather than a waste vent stream. A related 2024 US patent (integrated system for methane production using off-gas recycling) similarly returns CO₂-rich permeate to the digester.
Data and insights on this page are based on a limited patent and literature dataset and are for reference only. Figures may not represent the complete technology landscape.