Sampling & Conditioning Systems

Heating keeps the sample above its dew point so water, SO₃, and HCl do not condense on the way to the analyzer. Condensation causes sample loss, corrosion, and cross-contamination that invalidate the measurement. The ZS-SCS-800 maintains 180°C continuously from probe tip to analyzer inlet — above the typical acid dew point of around 160°C for wet flue gas.

Hastelloy C-276 wetted parts are required for flue gas containing HCl above ~50 mg/m³, HF, or high SO₃ — typically waste incinerators, chlor-alkali plants, and glass furnaces. SS316L is adequate for standard coal / gas combustion. Standard stainless lines corrode and adsorb acid gases, biasing the reading low, so the wetted-material choice is confirmed against the measured corrosive load per project.

Choose heated extractive (ZS-SCS-800) when the analyte is water-soluble or reactive (NH₃, HCl, HF, SO₃) and must never see condensation — the whole path stays hot. Choose cool-dry (ZS-SCS-600) when the analyzer needs a dry sample and the target species is not lost to the condensate, such as NDIR CO / CO₂ or paramagnetic O₂ where H₂O would bias the reading. Many sites run both paths for different analyzers off the same tap point.

Compressed instrument air (around 6 bar) is periodically pulsed back through the in-stack sintered filter to dislodge accumulated particulate. Cycle timing is configurable — from a few minutes to many hours — and is tuned to the dust loading of the duty, so high-particulate kiln and incinerator streams keep flowing without manual filter changes between service visits.

Standard runs are up to 30 metres; extended runs to 50 metres are available with additional heating zones. Longer runs require increased power-supply capacity and additional temperature-monitoring points, so the line length feeds directly into the power budget and the number of independently controlled heated zones at design time.

In-situ measurement avoids extraction entirely — the analyzer measures across the duct — which removes the conditioning chain, gives the fastest response, and suits reactive gases that would adsorb in a sample line, provided there is clean optical access and reliable window purge. Extractive sampling is preferred when the duct is too dusty or hot for direct optics, when the sample must be conditioned (dried, filtered, pressure-reduced) for the analyzer, or when several analyzers share one conditioned sample. Many CEMS racks combine both.

The ZS-SCS systems are compatible with all GESHINE ZS-series rack-mount analyzers and with most third-party analyzers that require a clean, heated or dried sample delivered at atmospheric pressure. The conditioning path is selected to match what the downstream analyzer needs at its inlet, so the same skid can feed a multi-gas CEMS rack.

Not always. For dry, clean, non-corrosive process gas, a modular probe and sintered filter (ZS-SCS-400) with a simple flow control can be sufficient — the full heated or cool-dry chain is reserved for wet, corrosive, dusty, or condensable streams. The right scope is set by the measured stream conditions, which is why GESHINE confirms the configuration against the temperature, dew point, dust, and corrosive load rather than over-specifying by default.