AMETEK Thermox WDG-V Flue Gas Oxygen Analyzer

Overview

The AMETEK WDG-V is a Thermox flue gas oxygen analyzer from AMETEK Process Instruments, designed to measure excess oxygen in combustion exhaust and to add a further layer of safety to the burner management system. It uses a close-coupled extractive design, drawing a small flue gas sample through a heated cell mounted directly at the stack or firebox wall, which gives a fast response across a wide range of applications with flue gas temperatures up to 1648 °C. With SIL 2 capability for excess O2, it can be used inside a safety instrumented system as well as for everyday combustion optimisation.

Refineries, gas plants, petrochemical complexes, power stations and desalination plants in Oman and the GCC operate large numbers of fired heaters, steam boilers and thermal oxidizers, where tight oxygen control saves fuel, limits emissions and prevents unsafe fuel-rich firing. Seven Star LLC supplies the AMETEK WDG-V to these users, with engineering support in Muscat for selection, probe sizing and spare parts.

Measurement Principle

The AMETEK WDG-V measures oxygen with a zirconium oxide cell held at a high, controlled temperature. At that temperature the ceramic conducts oxygen ions, and the difference in oxygen partial pressure between the flue gas on one side of the cell and a reference gas on the other generates a voltage that follows the Nernst equation. The electronics convert that voltage to percent oxygen, giving output ranges selectable from 0–1% up to 0–100% O2 with accuracy of ±0.75% of measured value or ±0.05% O2, whichever is greater.

An air- or nitrogen-driven aspirator, consuming about 3 SCFH at 3 to 6 psig, pulls sample gas from the probe past the cell and returns it to the process, so no sample is vented and no pump is needed. An integral flow sensor in the AMETEK WDG-V checks that sample is actually moving, and continual diagnostics track cell and detector age, cell resistance and analog current integrity. Response to a step change reaches 90% in under 11 seconds even with flame arrestors fitted.

Engineering Design of the AMETEK WDG-V

The AMETEK WDG-V is housed in a hinged, weather-resistant stainless steel IP65 (NEMA 4X) enclosure. Probe options are matched to flue gas temperature: 316 stainless steel probes for up to 704 °C and 310 stainless probes for up to 1024 °C, both in lengths from 910 to 2740 mm, and Hexoloy silicon carbide probes for up to 1648 °C in lengths from 600 to 1820 mm. Versatile flange options suit most stack and furnace connections. The AMETEK WDG-V handles sample dew points up to 200 °C and sample pressures of ±10 in. water gauge, and operates in ambient temperatures from −25 to 65 °C (−20 to 60 °C in hazardous areas).

For signals, the AMETEK WDG-V provides three isolated, fully scalable current outputs (4–20, 0–20, 20–4 or 20–0 mA, NAMUR configurable), five independent alarm relays and two-wire Modbus RTU, with HART available as an option. The optional AMEVision HMI adds a 4.2-inch colour display and can host up to eight analyzers, passing data to plant networks over Modbus or Ethernet TCP/IP with an embedded web server. Purged, remote-mount and floor-mount versions cover Class I Division 2 and ATEX or IECEx Zone 2 locations, and timed automatic calibration is possible with the optional Remote Calibration Unit.

Key Features

The points below explain why combustion engineers specify the AMETEK WDG-V for fired equipment.

• SIL 2 capability for excess O2 allows use in SIS combustion safety systems, supported by predictive diagnostics and proactive alarms.
• An industry-proven zirconium oxide sensor delivers accurate oxygen readings across ranges from 0–1% to 0–100%.
• The close-coupled extractive layout responds quickly, reaching 90% of a step change in under 11 seconds.
• An integral flow sensor verifies sample system integrity so a blocked probe cannot pass unnoticed.
• Probe materials up to Hexoloy silicon carbide handle flue gas temperatures up to 1648 °C.
• Three isolated analog outputs, five alarm relays, Modbus RTU and an optional HART interface simplify DCS integration.
• Ethernet connectivity through AMEVision enables remote monitoring from maintenance LANs or asset management systems.
• The analyzer is completely field-serviceable, which shortens repair time at remote sites.

Industrial Applications

In Oman’s refining and petrochemical sector, the AMETEK WDG-V is suited to crude and vacuum heaters, reformer and hydrotreater furnaces, steam methane reformers and ethylene cracking furnaces, where operators trim combustion air to the lowest safe excess oxygen to cut fuel use and NOx formation. Because the analyzer can feed a SIL-rated burner management system, it also helps protect fired heaters from dangerous low-oxygen conditions during load changes or burner faults. Gas plants and LNG facilities use the AMETEK WDG-V on regeneration heaters, hot oil heaters and thermal oxidizers that destroy acid gas and vent streams.

Power and water utilities across the GCC apply the AMETEK WDG-V to auxiliary and heat-recovery boilers and to steam generators that serve thermal desalination plants, while industrial users in Sohar, Duqm and Salalah fit it to process boilers, kilns and incinerators. Seven Star LLC supplies the AMETEK WDG-V with suitable probes, flame arrestors, calibration units and spare cells, and provides engineering support in Muscat for project and maintenance needs.

Technical Specifications

The key AMETEK WDG-V data below come from the manufacturer’s product data sheet (F-0510).

Related AMETEK Products

Plants running sulfur recovery or gas processing units can also review the AMETEK 900 tail gas air demand analyzer, AMETEK 5100P transportable TDLAS analyzer and AMETEK 7000-330-SE LCD host interface PCB.

How to Order

To order the AMETEK WDG-V, send Seven Star LLC a formal RFQ with flue gas temperature, probe length, mounting flange, hazardous-area classification and whether SIL 2 or HART is required. Our instrumentation team will confirm the configuration, current availability and delivery to sites in Oman and the GCC. The product datasheet can be downloaded from this page, and our engineers in Muscat can advise on calibration units, spare cells and integration with your burner management system.