New ST51A biogas flow meters resisting corrosion

AMS Instrumentation and Calibration introduces a new range of rugged thermal mass flow meters from Fluid
Components International (FCI), designed to resist corrosion in biogas

Featuring a robust
construction, FCI’s new rugged and reliable ST51A biogas flow meters meet the
needs of engineers responsible for biogas production involving industrial
organic waste and municipal wastewater treatment. Combining superior
measurement accuracy with high reliability and dependability, the ST51A measures
the valuable biogas that is released after organic waste from food or meat
processing plants, fermentation systems for dairy products or wineries and
breweries, as well as on-farm manure, and sewage treatment plants, is digested
under anaerobic conditions in reactor tanks.

This biogas is
measured with flow meters to support green co-gen energy systems or for
disposal by flaring. However, this potent mixture of combustible methane (CH4),
carbon dioxide (CO2), water and trace levels of corrosive hydrogen sulphide
(H2S), gas is problematic for many flow measuring technologies: while the combustible
properties of CH4 gas require HazEx safety approvals, the corrosive, sticky
nature of the H2S particles affects performance and can clog flow sensors,
leading to frequent labour-intensive cleaning.

FCI’s rugged thermal
mass ST51A biogas flow meter is designed specifically for dirty, potentially
hazardous biogas processes. It provides system operators with highly accurate
and repeatable mass flow measurement to facilitate system control, log gas
production data, and provide mandated safety and environmental reporting

Key features of ST51A
biogas flow meters include rugged 316 stainless steel body construction; Hastelloy-C22
thermal sensors; no-moving parts and non-clogging design eliminating the need
for constant cleaning under wet, dirty biogas conditions; full global Division
1, Zone 1, Ex safety approvals; electronics housed in a durable NEMA 4X, IP67
dust/water ingress protected and rugged, all-metal (aluminium or 316L stainless
steel) enclosure with dual conduit ports in NPT or M20 threading; installation
flexibility with transmitter integrally mounted with the flow element (probe)
or remote mounted; and dual 4-20 mA, NAMUR NE43 compliant outputs and a 500 Hz
pulse output as standard.

Model ST51A adds
digital communications via the HART, Version 7, protocol, providing plant staff
with digital data on flow rate and temperature parameters, the instrument’s
health, fault diagnostics and asset management info. It can also make field
configuration changes if needed by using standard HART portable communicators. All
of FCI’s thermal mass flow meters with HART protocol communications are
certified and registered with the Fieldcomm Group.

This insertion-style
flow meter is available in multiple probe lengths for installation into pipe
diameters from 2.5 to 24 inches. It is easily connected into the pipe via a _ inch
or ¾ inch NPT compression fitting. Its insertion style design needs only a
simple, single point tap into the process piping, requiring minimal technician

The ST51A flow meter
utilises constant power thermal dispersion mass flow technology, which employs
a slightly heated sensor that provides a subtle drying effect on condensating
moisture to make it highly effective (accurate) in moist biogas applications. Built-in
temperature compensation circuitry provides correct readings under variable
climate conditions from cold winters to hot summers.

The ST51A operates
over a wide measurement range of 0.3 to 400 SFPS (0,08 to 122 MPS) with 100:1
turndown. The instrument’s standard accuracy is ±2% reading, ±0.5% full scale,
with an optional configuration to provide higher accuracy to ±1% reading, ±0.5%
full scale.

For further
information, please visit the AMS Instrumentation and Calibration website or call 03-9017 8225, or
Freecall (NZ) 0800 442 743.

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