ZS8100-C2H2 Process Acetylene Analyzer

IEC 60599 defines DGA against gases dissolved in transformer oil, not free head-space, so online DGA always needs an oil-to-gas extraction stage — head-space equilibrium or polymer membrane — to strip dissolved C2H2 into a carrier stream that TDLAS can read. Direct laser interrogation of the oil matrix remains a research-grade concept and has not displaced extraction modules in field service. The ZS8100-C2H2 ships tuned for the gas-phase side of the loop; pairing with a validated oil-gas extraction skid is therefore a Conditional engineering-review path rather than a drop-in capability, and extracted-sample DGA per IEC 60567 / ASTM D3612 remains the principal workflow.

The near-IR C2H2 overtone feature at ~1.5 μm is narrower than anything a broadband filter-photometer sees. The instrument tunes across the selected line centre, fits a Voigt profile, and subtracts adjacent hydrocarbon wings so C2H4, C2H6 and CH4 are handled as part of the declared DGA background instead of being treated as arbitrary mixtures. Accuracy is specified with a representative hydrocarbon background per IEC 60567 sample preparation; unusually rich backgrounds (for example >5 %vol CH4) are handled by a dedicated application calibration rather than the default factory cal.

Metallurgical acetylene feed arrives dry but is typically entrained with oil mist from cylinder manifolds and blending skids. For header / blending-skid QA, the ZS-SCS-600 cool-dry chain is typically specified — coalescing filter, chiller to a stable 5 °C dew point, and 2 μm particulate catch — ahead of the analyzer cell. Heated sampling (ZS-SCS-800) is specified only when an upstream scrubber or wet-trap could condense on the cell window. CGA G-1.1 commodity-acetylene purity governs the spec envelope; the analyzer reports C2H2 %vol plus impurity ppm excursions against that spec.

Under the GESHINE maintenance plan the TDLAS signal chain runs an automatic zero-check against a sealed reference cell at user-settable intervals (typical daily) and a manual span verification with a certified C2H2 mixture every 6 months for process duty, quarterly for DGA-rated service. Because the principle is optical-only (no chemistry consumable) there is no electrochemical cell or reagent to swap; the dominant service items are the laser module and the window purge, both field-replaceable without cell re-alignment.

The ZS8100-C2H2 is intended for continuous in-line / on-skid duty with optional ATEX Ex d enclosure, 24/7 operation, and 4–20 mA / Modbus hand-off to SCADA. The bench-top TDLAS review path serves DGA laboratory confirmation, inter-comparison, and periodic audit of portable cylinder mixtures — it trades continuous-duty packaging for a tighter multi-pass cell and metrology-grade calibration reports. Operations logging transformer DGA trend data online run the ZS8100; reference-sample sign-off belongs to the bench-top TDLAS review path, giving an online monitoring plus lab confirmation workflow.