AMS RHADOX 7100 Online Wobbe Index & Air Demand Analyzer
| Brand | AMS |
|---|---|
| Origin | Germany |
| Model | RHADOX 7100 |
| Explosion Protection | ATEX II 2G Ex pxb IIB+H2 T4 Gb X (Zone 1) / ATEX II 3G IIB+H2 T3 Gc (Zone 2) |
| Response Time (T90) | 10–30 s |
| Repeatability | ≤1.0% of measured value |
| Long-term Drift | ≤2% of full scale per month |
| Temperature Drift | <0.02% / K (relative to span end) |
| Air Demand Range | 1.5–30 m³ air/m³ gas |
| Wobbe Index Range | 5–120 MJ/m³ |
| Analog Output | 2 × 4–20 mA (galvanically isolated) |
| Display | 2×16-character backlit LCD + optional full-color status display |
| Operating Temperature | –5°C to +45°C (electronics), +5°C to +60°C (gas path) |
| Gas Inlet/Outlet | 6/12 mm stainless steel tubing or flanged connections |
| Sample Flow Rate | 20–100 Nl/h (process gas), 50–500 Nl/h (instrument air) |
| Gas Pressure | ≥0.1 bar(g), max 17 bar(g) |
| Instrument Air | ≥2 bar(g), max 8 bar(g) |
| Power Supply | 115/230 V AC, 50–60 Hz, 500 VA |
| Enclosure Rating | IP65 |
| Dimensions (H×W×D) | 1000×900×350 mm |
| Weight | ~100–125 kg (configurable) |
Overview
The AMS RHADOX 7100 is a certified online gas analyzer engineered for continuous, real-time determination of Wobbe Index and theoretical air demand in industrial fuel gases and waste gas streams. It operates on the catalytic combustion principle: process gas and instrument air are metered, conditioned to identical temperature and pressure, mixed homogeneously, and oxidized in a high-stability catalytic reactor. Oxygen concentration in the post-combustion stream is continuously monitored via electrochemical or paramagnetic sensing—enabling stoichiometric calculation of air demand and derivation of Wobbe Index (WI) using calibrated thermodynamic correlations. Unlike calorimetric or chromatographic methods, RHADOX 7100 delivers direct, interference-resistant measurement without requiring gas composition assumptions or external lab reference data. Its design targets stable combustion control in dynamic gas supply environments—particularly where feedstock variability (e.g., blast furnace off-gas, biogas, refinery purge streams) demands rapid, traceable response to composition shifts.
Key Features
- ATEX-certified dual-zone explosion protection: II 2G Ex pxb IIB+H2 T4 Gb X (Zone 1) and II 3G IIB+H2 T3 Gc (Zone 2), enabling safe deployment in classified hazardous areas without additional purging enclosures.
- Dual independent 4–20 mA analog outputs with galvanic isolation—each configurable for Wobbe Index, air demand, or diagnostic status signals—compliant with IEC 61000-6-2/4 EMC standards.
- Integrated catalytic converter with auto-regeneration logic ensures long-term stability against sulfur, siloxanes, and hydrocarbon fouling; optional pre-catalyst for raw sample conditioning extends maintenance intervals.
- Full-featured local interface: dual-line 16-character backlit LCD with real-time parameter display (WI, air demand, O₂ residual, system status), plus optional color graphical display for hierarchical alarm visualization (system, operational, service levels).
- Modular pneumatic architecture: gas conditioning unit (pressure regulation, filtration, flow control) physically separated from electronics cabinet per IP65-rated enclosure—facilitating maintenance under live operation and reducing cross-contamination risk.
- Remote operability via RS232 (standard), RS485 (optional), or Ethernet (optional) supporting Modbus RTU/TCP protocols—enabling integration into DCS/SCADA systems with timestamped event logging and remote calibration initiation.
Sample Compatibility & Compliance
The RHADOX 7100 accepts a broad range of combustible industrial gases—including blast furnace gas (BFG), coke oven gas (COG), syngas, biogas, landfill gas, and refinery off-gases—with H₂ content up to 70 vol%, CO up to 35 vol%, CH₄ up to 95 vol%, and total hydrocarbons ≤ C₆. Particulate load must be <1 mg/Nm³; condensable hydrocarbons and heavy tars require upstream coalescing filters. The analyzer complies with EN 61000-6-2 (immunity) and EN 61000-6-4 (emissions), meets PED 2014/68/EU for pressure equipment interfaces, and supports audit-ready documentation per ISO/IEC 17025 and ASTM D4343 (Wobbe Index standard test method). For regulated environments, firmware supports configurable audit trails, electronic signatures, and user-access-level management aligned with FDA 21 CFR Part 11 requirements when deployed with validated software configuration.
Software & Data Management
Firmware v3.2+ provides embedded data handling including 30-day circular buffer storage (1-min resolution), configurable alarm thresholds (high/low/deviation), and automatic event-triggered data export via serial/Ethernet. Calibration history—including date, operator ID, reference gas lot numbers, and pre-/post-calibration deviation reports—is retained with tamper-evident timestamps. Optional AMS Analytical Suite (Windows-based) enables trend analysis, multi-analyzer fleet monitoring, report generation (PDF/CSV), and compliance documentation (e.g., GLP-style calibration certificates). All digital communications support TLS 1.2 encryption and role-based authentication—meeting cybersecurity baseline requirements for Industry 4.0 integration.
Applications
- Blast furnace and basic oxygen furnace (BOF) off-gas valorization—optimizing burner staging and air/fuel ratio control to maximize thermal efficiency while minimizing NOₓ formation.
- Chemical and petrochemical plants—monitoring purge gas composition prior to flare or recovery, ensuring consistent Wobbe Index for downstream fired heaters and steam generators.
- Wastewater treatment and anaerobic digestion facilities—real-time biogas quality assurance for combined heat and power (CHP) engine protection and grid injection compliance.
- Glass manufacturing—precise WI feedback for regenerative furnace combustion tuning, reducing refractory wear and improving product optical homogeneity.
- Hydrogen-blended natural gas networks—verifying blend consistency and detecting compositional excursions affecting appliance safety and energy billing accuracy.
FAQ
What calibration gases are required for initial setup and routine verification?
Two certified calibration gases are mandatory: one representing the low end and one the high end of the target Wobbe Index and air demand ranges. Typical examples include synthetic natural gas (SNG) and low-BTU blast furnace gas simulants—traceably certified to ISO 6142 and supplied with uncertainty statements.
Can the RHADOX 7100 operate unattended for extended periods?
Yes—designed for 24/7 operation with mean time between failures (MTBF) exceeding 18 months. Integrated diagnostics monitor catalyst health, sensor drift, flow stability, and pressure integrity; alerts trigger via analog output or digital interface before measurement uncertainty exceeds ±1.5% of span.
Is field recalibration possible without specialized tools?
Yes—calibration is initiated from the front-panel menu or remotely via Modbus command. No manual potentiometer adjustment is required; all gain/offset corrections are stored in non-volatile memory with version-controlled firmware compatibility.
How does the analyzer handle gas streams with variable moisture or particulate content?
Condensate is removed via integrated Peltier-cooled demister (optional) or external chiller; particulates are filtered to <0.3 µm via sintered stainless steel elements. The catalytic reactor’s thermal mass and active regeneration protocol mitigate transient poisoning effects from intermittent contaminants.
Does the system support predictive maintenance logging?
Yes—embedded diagnostics log catalyst temperature profiles, O₂ sensor polarization cycles, and flow regulator duty cycles. These parameters feed into AMS’ optional Predictive Health Module, which estimates remaining service life and recommends intervention windows based on statistical trend analysis.
