CUBIC INSTRUMENTS BF-3000 Ultrasonic Biogas Flow Meter

Overview

The CUBIC INSTRUMENTS BF-3000 Ultrasonic Biogas Flow Meter is an intrinsically safe, dual-function instrumentation system engineered for continuous, real-time measurement of volumetric flow rate and methane (CH₄) concentration in raw biogas streams. Unlike thermal or differential pressure-based meters, the BF-3000 employs transit-time ultrasonic technology—where paired transducers measure the time difference between upstream and downstream ultrasonic pulses—to determine gas velocity with high linearity across a wide dynamic range. This principle enables accurate flow quantification independent of gas composition, density, or viscosity—critical for variable biogas streams containing CO₂, H₂S, moisture, and trace contaminants. Integrated temperature and absolute pressure sensors provide real-time compensation, allowing automatic calculation of standardized volumetric flow (e.g., Nm³/h at 0 °C, 101.325 kPa) per ISO 6976 and ISO 5167 conventions. Designed specifically for biogas infrastructure—from small farm-scale digesters to municipal landfill gas recovery systems—the BF-3000 meets the metrological requirements of biogas subsidy verification, carbon credit reporting, and regulatory compliance under national renewable energy directives.

Key Features

• Transit-time ultrasonic flow sensing with no moving parts, ensuring zero mechanical wear and long-term metrological stability without recalibration drift
• Dual-parameter output: simultaneous measurement of volumetric flow rate (m³/h) and CH₄ concentration (30–100% vol) with 1 ppm resolution and ≤15 s response time
• Ceramic-coated ultrasonic transducers resistant to H₂S corrosion and condensate exposure—validated for continuous operation in biogas with up to 10,000 ppm H₂S and >95% relative humidity
• Integrated Pt100 temperature sensor and piezoresistive pressure transducer for automatic compensation to standard conditions (ISO 12213-2)
• Low-flow sensitivity optimized for intermittent, low-velocity biogas supply—capable of stable measurement down to 0.1 m/s gas velocity across all nominal diameters (DN32–DN300)
• Intrinsically safe design certified to Ex ib IIA T4 Gb (IEC 60079-0, -11), suitable for Zone 1 hazardous areas common in biogas upgrading and compression stations
• Robust aluminum housing with IP65-rated enclosure, field-serviceable electronics, and dual-power architecture (5 V safety-barrier input + 3.6 V ER26500 lithium thionyl chloride battery backup)

Sample Compatibility & Compliance

The BF-3000 is validated for use with untreated and partially cleaned biogas streams containing methane (30–100%), carbon dioxide (0–70%), hydrogen sulfide (up to 10,000 ppm), water vapor (saturated), and trace siloxanes or ammonia. It complies with EN 16726:2016 for biogas quality monitoring systems and supports traceability per ISO/IEC 17025 requirements when deployed with documented calibration procedures. While not a certified custody-transfer device per OIML R137, its ±1.5% accuracy class satisfies internal accounting, process optimization, and incentive program reporting (e.g., China’s Renewable Energy Tariff Subsidy Policy, EU RED II Annex IX). All firmware and configuration logs are timestamped and non-volatile, supporting basic audit trail functionality aligned with GLP principles.

Software & Data Management

Data acquisition and configuration are managed via Modbus RTU over RS-485 interface, compatible with SCADA, DCS, and PLC platforms (Siemens S7, Rockwell ControlLogix, Schneider EcoStruxure). The meter outputs six primary registers: instantaneous flow (Nm³/h), cumulative flow (Nm³), CH₄ % vol, static pressure (kPa), temperature (°C), and status flags (e.g., signal quality, sensor fault). Optional PC-based configuration utility (Windows/Linux) enables zero/span adjustment, flow unit selection, damping settings, and alarm thresholds. No cloud connectivity or proprietary software subscription is required; raw data streams are protocol-transparent and integrable into existing MES or environmental monitoring systems without middleware.

Applications

• On-farm anaerobic digestion plants: real-time feedstock-to-gas yield validation and digester performance trending
• Municipal wastewater treatment facilities: effluent biogas quantification for CHP fuel scheduling and GHG emission reporting (IPCC Tier 2)
• Landfill gas recovery sites: flow and CH₄ concentration monitoring for LFG-to-energy projects eligible under Clean Development Mechanism (CDM) or Verra VM0018
• Biogas upgrading stations: inlet/outlet flow comparison for membrane or PSA system efficiency assessment
• Urban natural gas blending points: verification of biomethane injection ratios prior to grid entry (per EN 16723)
• Research and pilot-scale digesters: high-temporal-resolution data collection for kinetic modeling and process control algorithm development

FAQ

Does the BF-3000 require periodic recalibration?
No routine recalibration is mandated under normal operating conditions; however, annual verification against a traceable reference standard (e.g., bell prover or calibrated sonic nozzle) is recommended per ISO 10790 for critical applications.
Can it operate in wet gas conditions with free liquid carryover?
The BF-3000 is rated for saturated gas but not for two-phase flow; installation must include upstream drip legs and moisture separation to prevent liquid accumulation in the measurement tube.
Is CH₄ concentration measurement certified to international standards?
CH₄ quantification uses factory-calibrated ultrasonic spectral analysis—not NDIR or GC—and is intended for relative process control and subsidy verification, not legal metrology-grade certification.
What pipe materials are compatible with BF-3000 flanged variants?
Standard configurations support carbon steel, stainless steel (304/316), and GRP piping; custom gasket materials (EPDM, Viton) are available for aggressive H₂S environments.
How is intrinsic safety maintained during battery replacement?
The ER26500 battery compartment is sealed and rated Ex ib; replacement must be performed in non-hazardous areas following manufacturer instructions to preserve explosion protection integrity.