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ADBA member Geotech enhances its biogas analyser


The latest static biogas analyser from Geotech, the GA3000 PLUS, can now optionally monitor up to three sample points and hydrogen sulphide (H2S) levels at 0-50 ppm to 0-10,000 ppm.

As before, it analyses methane (CH4) carbon dioxide (CO2) and oxygen (O2). The new developments, as options, enhance the already widely used ATEX Zone 2 certified GA3000 for landfill gas and AD biogas analysis.

Multi-sample point biogas analysis

With three sample points, AD operators can measure gas quality from more than one digester to check output from each before the gas is mixed and then check mixed-gas before it goes to the CHP engine. Tracking production at source can help improve output and spot problems early. Landfill operators can measure different gas field sections before the gas is mixed. By measuring the mixed gas going to CHP and to flare, operators can control both. Thus with multi-point sampling, operators achieve more analysis from one static analyser giving even better value. A 4-20 mA output for each gas is standard as is MODBUS digital output, allowing communication with SCADA systems. Alarm relays are user configurable.

Two H2S sensors, high and low

The GA3000 PLUS offers the advantage of high- and low-range H2S measurement in the same system but from different sample points – usually for biogas monitoring before and after desulphurisation. This scrutinises clean-up equipment performance and checks if filter material needs replacing or regenerating. By having two sensors set to high and low ranges, each can react quickly to appropriate H2S levels without reaction time delays or purging between high-level and low-level readings

Variable H2S levels

Because AD H2S levels in biogas can vary with feedstock, the GA3000 PLUS offers AD users a choice of H2S ranges. This can assist with monitoring before and after desulphurisation. Low H2S monitoring is relevant when an AD digester only produces low-level H2S due either to the nature of the feedstock or to H2S reduction treatment (e.g. ferric dosing or O2 injection).

For AD and landfill, H2S measurement pre- and post-treatment shows the effectiveness of H2S removal and maintaining H2S below acceptable CHP thresholds and compliance with CHP manufacturer warranty contracts. Vital for CHP restart and protection against sudden gas level changes, the GA3000 PLUS static biogas analyser can pay back in weeks or even days.

The Geotech GA3000 PLUS can also measure carbon monoxide (CO), hydrogen (H2).

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