Renewable Natural Gas (RNG) Process Solutions

Raw biogas must be upgraded to >96–98% CH₄ with CO₂ <2–3%, O₂ <0.2–0.5% and a controlled water dew point before it meets grid or vehicle-fuel spec. Whether the plant uses membranes, PSA, water scrubbing or amine, the process depends on a supporting chemistry program that controls scaling, corrosion, fouling and foaming — and protects methane recovery (target methane slip <1–2%). 

Digestate is frequently the largest single operating cost in a digestion facility. Effective conditioning and dewatering — pushing cake solids from raw slurry up to 18–30% DS on a centrifuge — slashes hauling volume and improves nutrient recovery. The lever is polymer: correct make-down, aging and charge-matched dosing at ~4–12 kg active polymer per tonne of dry solids. 

The CO₂ stripped during upgrading is not just a waste stream — it is a sellable co-product. Adicomp CO₂ compression stations are skid-mounted, inverter-controlled systems with stainless-steel, corrosion-resistant gas-wetted components that capture, compress and prepare CO₂ for reuse in agriculture, food processing, chemical production, methanation, liquefaction and dry-ice production. Specs reach up to 25 bar(g) operating pressure, free gas delivery up to 6,000 Nm³/h and absorbed power up to 700 kW. Adding CO₂ valorization turns a disposal cost into a second revenue line and strengthens the facility's carbon-intensity story. 

Before injection into the gas grid, biomethane must be odorized to utility spec — typically tetrahydrothiophene (THT) at 20–25 mg/Nm³ or mercaptan blends at 8–16 mg/Nm³ — while flow is measured and compliance is monitored. Unlike conventional transmission lines, biomethane injection rates are highly variable, often ranging from 30 to 5,000 Nm³/h, which makes accurate odorant proportioning far harder than on a conventional main. 

ODOROY® and YZ NJEX injection systems deliver accurate odorant dosing across a wide operating range, while the YZ LVO odorizer is optimized for the very low flows typical at commissioning — down to 10 Nm³/h (6.5 scfm), with a zero-methane-emission design, 316 SS wetted parts, Viton elastomers and a MAOP of 1,450 psi. 

Key capabilities across the YZ odorization platform: 

• High-accuracy odorant injection for variable, low biomethane flows.
• Continuous odorization-performance monitoring with integrated alarms and diagnostics.
• Remote telemetry, inventory management and compliance reporting through Aircom™ — plus predictive-maintenance support.
• Automated operation with minimal operator intervention, proven across RNG, biomethane and natural-gas distribution.

YZ Systems and Milton Roy Europe will support GRDF biomethane plants in France with THT odorization skids designed for safe, reliable RNG injection into the gas distribution network.