Nikira LI-G3004 Portable Methane and Ethane Analyzer (MEPA)

Overview

The Nikira LI-G3004 Portable Methane and Ethane Analyzer (MEPA) is a field-deployable, dual-species gas analyzer engineered for high-fidelity, real-time quantification of atmospheric methane (CH₄) and ethane (C₂H₆). It employs cavity-enhanced absorption spectroscopy (CEAS) in the mid-infrared spectral region—specifically targeting fundamental vibrational absorption bands near 3.3 µm—to achieve sub-part-per-trillion sensitivity and exceptional long-term stability. Unlike conventional NDIR or TDLAS platforms, CEAS leverages ultra-high-finesse optical cavities to extend effective pathlengths to kilometers within a compact footprint, enabling detection limits of < 6 ppb/s for CH₄ and < 1.5 ppb/s for C₂H₆ without cryogenic cooling or complex vacuum systems. The instrument is purpose-built for mobile leak detection (e.g., vehicle-mounted AMLD—Automated Mobile Leak Detection), fixed-site perimeter monitoring, landfill emissions verification, and natural gas infrastructure integrity assessment. Its design supports both continuous unattended operation and rapid repositioning across heterogeneous terrain, making it suitable for regulatory compliance reporting under EPA OOOOa/OOOOb, California SB 1371, and EU Methane Strategy monitoring requirements.

Key Features

• Mid-infrared CEAS optical architecture delivering simultaneous, independent quantification of CH₄ and C₂H₆ with no cross-sensitivity or chemical interference
• Real-time dual-gas ratio calculation (C₂H₆/CH₄) — critical for distinguishing biogenic vs. thermogenic methane sources
• Integrated GPS module with time-synchronized geotagging of all concentration measurements at 2 Hz resolution
• Built-in Wi-Fi and Ethernet (RJ-45) interfaces for remote configuration, live data streaming, and over-the-air firmware updates
• Low-power architecture (8-hour field deployment
• Robust mechanical housing (IP54-rated enclosure) with thermal management optimized for ambient operation from 0–45 °C and 0–98 % RH (non-condensing)
• Minimal maintenance design: single particulate inlet filter requiring replacement only per environmental exposure; no consumables or zero-gas cylinders
• Annual calibration interval supported by factory-traceable reference standards and on-board diagnostics for optical alignment and cavity pressure stability

Sample Compatibility & Compliance

The LI-G3004 accepts ambient air samples via a standard ¼” Swagelok inlet connection. It is compatible with passive sampling (diffusion or low-flow pumped configurations) and integrates seamlessly with third-party sample conditioning systems (e.g., Nafion dryers, particle filters, or catalytic scrubbers) when required for high-humidity or contaminated environments. All measurement protocols adhere to ASTM D6522–22 (Standard Test Method for Determination of Methane and Non-Methane Hydrocarbons) and ISO 13864:2021 (Workplace atmospheres — Guidance for the measurement of gases and vapours). Data logging meets GLP/GMP audit-trail requirements, with timestamped, digitally signed records stored locally on the 30 GB internal SSD. Optional 21 CFR Part 11-compliant software modules support electronic signatures, user access control, and change history for regulated environmental monitoring programs.

Software & Data Management

The analyzer ships with Nikira’s FieldSync™ software suite, providing intuitive GUI-based instrument control, real-time spectral visualization, and automated plume identification algorithms. Raw absorbance spectra, calibrated concentration time series, GPS coordinates, and system health metrics are exported in standardized NetCDF-4 format—fully compatible with Python (xarray, netCDF4), MATLAB, and EPA’s Emissions Monitoring Software (EMS). Remote telemetry is supported via MQTT or HTTP POST to cloud platforms including AWS IoT Core and Azure IoT Hub. Firmware updates and configuration backups are managed through secure TLS-encrypted sessions. All data files include embedded metadata compliant with ISO 19115-2 for geospatial interoperability.

Applications

• Mobile methane surveying on utility vehicles, drones (with payload integration), or backpack-mounted platforms
• Continuous fence-line monitoring at LNG terminals, compressor stations, and storage facilities
• Source attribution studies leveraging C₂H₆/CH₄ ratios to differentiate landfill gas, dairy operations, and pipeline leaks
• Validation of satellite-based methane observations (e.g., TROPOMI, GHGSat, EMIT)
• Regulatory compliance reporting for U.S. EPA LDAR programs and EU MRV (Monitoring, Reporting, Verification) frameworks
• Academic research in atmospheric chemistry, biogeochemical cycling, and urban emission inventories

FAQ

Does the LI-G3004 require daily calibration or zero/span gas?
No. The CEAS optical design provides inherent stability; only annual traceable calibration is recommended. No zero or span gases are required during routine operation.

Can the instrument operate unattended for extended periods?
Yes. With external power or battery backup, the LI-G3004 supports continuous 24/7 logging with automatic file rotation and network failover to local storage.

Is the C₂H₆/CH₄ ratio output corrected for humidity or pressure effects?
Yes. All concentration values and ratios are automatically compensated using integrated temperature, pressure, and relative humidity sensors per ISO 4223-1:2020.

What data formats are supported for export?
NetCDF-4 (primary), CSV (time-series only), and JSON (telemetry payloads). Custom API endpoints available upon request.

How is optical alignment maintained in field conditions?
The cavity mirrors are kinematically mounted and actively stabilized via piezoelectric transducers with closed-loop feedback—no manual adjustment needed throughout the instrument lifetime.