Rugged gas flow meter provides precise, safe and compliant measurements for environmental applications including wastewater treatment, biogas and landfill facilities

Wastewater treatment operations require a high level of accuracy in measuring gas production from digester tanks, this is crucial for both the process efficiency and environmental compliance. Technicians can turn to Fluid Components International (FCI)'s ST80 Series Thermal Flow Meter for unsurpassed precision in mass flow measurement with confidence.

The main challenge lies in the complex composition of digester waste gas, which mainly consists of methane (CH4) and carbon dioxide (CO2), often with other trace gases. This composition varies because of factors such as process conditions and temperature. Typical averages hover around 65% (±5%) CH4 and 35% (±5%) CO2. Notably, this gas is moisture-laden and impure, containing entrained hydrogen sulphides that can condense and accumulate on pipe surfaces.

FCI's ST80 Series is a rugged thermal dispersion technology meter with an insertion-style design, that provides the ideal solution to this tricky application. It lacks moving parts and offers comprehensive global Hazardous Location (HazEx) approvals, which are crucial when dealing with combustible gases such as CH4. Key features of the ST80 Series include Adaptive Sensing Technology™ (AST™), which ensures accuracy despite ever-changing conditions. The ST80 includes a range of flow sensors, including a wet gas flow element, tailored to cater to moisture-rich digester gas applications. The robust transmitter enclosure, which is available in aluminum or stainless steel, has a NEMA4X/IP67 rating, ensuring durability in harsh environments.

The ST80's wide process connection selection facilitates installation in a variety of pipe or duct configurations. Output options are flexible, ranging from traditional 4-20 mA analogue to advanced digital bus communications like HART, Foundation Fieldbus, PROFIBUS, etc. The graphical LCD display provides real-time insights, showcasing flow rate, totalised flow, temperature, alarms, and diagnostic messages in a user-friendly format. Performance specifications include a flow range of 0.25 to 1000 SFPS (0.07 to 305 NMPS), flow accuracy of ±1.0% of reading, 0.5% full scale, and repeatability of ±0.5% of reading. The turndown ratio is factory-set and field-adjustable from 2:1 to 100:1.

Accurate measurement of digester gas flows is vital for process optimisation, environmental regulation adherence, and fuel utilisation in Combined Heat and Power (CHP) systems. The ST80 Series Flow Meter's comprehensive approvals, ranging from ATEX and CE to SIL (IEC 61508), ensure compliance and operational safety.