LESHI SE304 Portable SO₂ Infrared Analyzer

Overview

The LESHI SE304 Portable SO₂ Infrared Analyzer is a field-deployable, NDIR-based gas measurement system engineered for quantitative determination of sulfur dioxide (SO₂) in ambient air, stack emissions, and process streams. It operates on the fundamental principle of non-dispersive infrared absorption spectroscopy: SO₂ exhibits strong, selective absorption at a characteristic wavelength of 7.3 µm within the mid-infrared region (6.82–9 µm). As sampled gas passes through the optical cell, a stabilized infrared source emits radiation at this fixed wavelength; attenuation of the beam intensity follows the Lambert–Beer law, enabling linear calibration between absorbance and SO₂ concentration across the configured range. Designed in strict accordance with HJ 692–2011 (“Determination of Sulfur Dioxide in Stationary Source Exhaust Gases — Non-Dispersive Infrared Spectrophotometry”), the SE304 delivers metrologically traceable measurements suitable for regulatory-compliant emission monitoring, continuous process verification, and academic laboratory instruction.

Key Features

• High-stability NDIR sensor optimized for SO₂ detection at 7.3 µm, delivering long-term baseline stability and minimal zero drift
• Ruggedized industrial housing with IP54-rated enclosure for operation in harsh field environments including high-humidity and particulate-laden exhaust ducts
• Capacitive touch-enabled LCD interface with intuitive menu navigation, real-time concentration display, and on-device data logging
• Sub-60-second thermal stabilization enables rapid deployment and sequential multi-point sampling without extended wait times
• Fully customizable measurement span: factory-calibrated ranges available from 0–50 ppm to 0–5000 ppm, with linearity deviation ≤ ±2% FS over full scale
• Modular architecture facilitates field replacement of optical cell, filter assemblies, and pump modules—no specialized tools required
• Integrated stainless-steel probe (300 mm length, 12 mm OD) with PTFE-lined flexible sampling hose (2 m standard) for safe insertion into hot or corrosive flue gas streams
• Automatic sensor recovery protocol ensures rapid return to baseline upon SO₂ over-range exposure, minimizing downtime during transient excursions

Sample Compatibility & Compliance

The SE304 accommodates gaseous samples across a broad operational matrix: ambient air (25 °C, 1 atm), cooled and filtered stack effluent ( 15 vol.%), optional condensate removal modules—including chilled mirror dew point controllers and permeation dryers—are configurable per site-specific requirements. All factory calibrations are performed using NIST-traceable SO₂ standards (certified reference gases, CRM 1720a–1720d), and instrument validation adheres to QA/QC protocols outlined in HJ 692–2011. While not certified for continuous emissions monitoring system (CEMS) compliance under EPA PS-12 or EN 15267, the SE304 meets performance criteria for periodic verification, leak detection surveys, and educational demonstration per ISO 12039 and ASTM D5402.

Software & Data Management

Data acquisition and reporting are supported via embedded firmware with dual-mode connectivity: USB-C interface for direct PC transfer and Bluetooth 5.0 for wireless telemetry to Android/iOS field tablets. The onboard memory logs timestamped SO₂ values (1 Hz default), temperature, pressure, and flow rate at user-defined intervals (1 s to 60 min). Export formats include CSV and XML, compatible with LIMS integration and post-processing in MATLAB, Python (Pandas), or Excel. Audit trails record all configuration changes, calibration events, and zero/span adjustments—supporting GLP-aligned documentation practices. Firmware updates are delivered via signed binary packages to ensure integrity and version control.

Applications

• Regulatory stack testing for coal-fired boilers, cement kilns, and metal smelters under provincial environmental supervision programs
• Real-time SO₂ profiling during combustion optimization trials in R&D test rigs and pilot-scale incinerators
• Verification of desulfurization system efficiency (e.g., wet FGD, dry sorbent injection) via upstream/downstream paired measurements
• Undergraduate and graduate teaching modules on gas-phase spectroscopy, environmental instrumentation, and emission control engineering
• Mobile ambient air quality mapping in urban corridors and industrial buffer zones using GPS-synchronized sampling campaigns

FAQ

Does the SE304 require external power for field operation?
No—the unit operates on a rechargeable Li-ion battery pack rated for ≥8 hours of continuous measurement at 25 °C, with optional 12 V DC vehicle adapter support.
Can the instrument measure other gases besides SO₂?
The SE304 is optically tuned exclusively for SO₂ at 7.3 µm; cross-sensitivity to CO₂, NO₂, or H₂O vapor is actively compensated via dual-wavelength referencing and factory characterization.
Is calibration traceable to international standards?
Yes—each unit ships with a certificate of calibration referencing NIST SRM 1720 series gases, and annual recalibration services are available through LESHI’s Beijing service center.
What maintenance intervals are recommended?
Optical window cleaning and particulate filter replacement every 3 months under continuous stack use; pump diaphragm inspection annually or after 2000 operating hours.
How is data integrity ensured during transmission?
All wireless transfers employ AES-128 encryption, and local storage includes cyclic redundancy checksums (CRC-32) for each logged record.