AMETEK Western Research 931 Single-Gas H2S Analyzer

The AMETEK Western Research 931 is a rugged, explosion-proof single-component photometric analyzer that measures one UV-absorbing gas species, most often hydrogen sulfide (H2S). It is a hot-wet design: the sample cell sits in a heated oven so that hydrocarbons and water do not condense in the optics, and a fully integrated sample system controls the dew point without the risk of plugging, contaminating or flooding the analyzer.

Seven Star LLC supplies the 931 from Muscat for sulfur recovery, gas treating and sour gas pipeline duties, with the manufacturer data sheet and application questions handled before quotation.

A fixed-optics UV photometer built for sour gas duties

Instead of a filter or chopper wheel that alternates between measure and reference wavelengths, the 931 uses a fixed optical configuration with pulsed UV lamps. AMETEK states that this raises light throughput, lowers noise and reduces maintenance. The lamps are high-intensity, low-energy hollow cathode sources that emit at precise wavelengths, giving a resolution better than 0.02 nm and a linearity with less than 1 percent deviation over three to four orders of magnitude.

The standard configuration measures H2S. Because some process species do not absorb in the ultraviolet, a thermal conductivity detector (TCD) can be added for hydrogen (H2), and the UV channel can alternatively be configured for sulfur dioxide (SO2), carbonyl sulfide (COS), carbon disulfide (CS2) or ammonia (NH3). The data sheet also lists CO2 among other measurements available.

• No moving parts in the optical path, with pulsed UV lamps instead of a chopper wheel
• Heated cell oven and integrated sample system for hot-wet service
• Optional Heated Acid Gas Probe (HAG) allowing the sample to be returned to the process
• Stream-switching capability and minimal span drift

Technical specifications

Where the 931 is used and what to confirm before ordering

AMETEK lists amine-based tail gas treating (with the optional H2 channel), sulfur recovery unit feed gas analysis, well head gas and sour gas pipelines as the typical applications, in the sulfur recovery, tail gas treating and sour gas pipeline markets.

The 931 is quoted against a stream, not a catalogue number. Before ordering, confirm the component to be measured and its range, the full sample composition including water and hydrocarbons, sample pressure and temperature at the tap, the sample transport arrangement (including whether the heated probe is wanted), area classification and the certificate set required, the outputs and communication needed, and the 120 or 240 VAC supply. For a replacement, send the analyzer serial number and any part numbers from the existing panel.

Documents and quotation

To request a quotation for the 931 analyzer, send Seven Star LLC the full model or order code, quantity, and any nameplate data from an existing unit that is being replaced or matched. Our Muscat team checks the request against the manufacturer document, which can be downloaded from this page, and replies with a formal quotation. Prices, stock and lead times are confirmed per inquiry.

Related reading on this site: the gas analyzer systems category, and AMETEK 930 sulfur pit H2S analyzer.