Measuring landfill gas accurately with ST51 flow meter

AMS Instrumentation and Calibration has introduced a new thermal mass flow meter designed to
provide accurate measurement of solid waste landfill gas flow for use in co-generation
electric power engines.

Landfills produce a
mixture of methane and carbon dioxide gases with traces of nitrogen, oxygen and
other gases. These gases are extracted from multiple wellheads and collected
through a network of pipes to a common header pipe. The collected ‘greenhouse
gas’ is either disposed of, or recovered as a fuel source for co-generation
engines to produce electric power.

The advanced ST51
Series thermal mass flow meter from Fluid Components International (FCI)
provides process and plant engineers challenged with measuring wet dirty mixed
gases in solid waste operations, accurate measurement of the landfill gas being
extracted for optimising effectiveness, for reporting to environmental agencies
and for carbon credit programs. The ST51 flow meter provides accurate measurement
under challenging application conditions such as wet and/or dirty gas, mixed
composition gases, potentially explosive installation environments, wide
variations in flow rates, seasonal swings in gas and ambient temperatures, and larger
line sizes.

Flow meters that
perform accurately with repeatability and safely under these conditions must
meet a number of other requirements such as a multi-function design that
provides flow rate, totalised flow data and temperature outputs; ability to be
calibrated for methane with mixed gases; offer temperature compensation; have
no moving parts or orifices that clog or foul; be available with single tap
insertion designs; adjust automatically to wide turndowns over a wide flow
range including extremely low flow sensitivity; and agency approval for use in
Division 2 [Zone 2] and often Division 1 [Zone 1] hazardous environments.

FCI’s ST51 flow
meters are specifically designed for the flow measurement of methane-based
gases such as biogas, digester gas, landfill gas and natural gas as well as air,
compressed air or nitrogen.

Key features include
a proven thermal dispersion flow sensor available in an insertion-style package
developed for use in pipe diameters from 2.5 to 24 inches [63 to 610 mm]; insertion
style instrument allowing easy installation into the pipe via a 0.5 or 0.75
inch NPT compression fitting; measurement range from 0.08 to 122 MPS with
turndown ratio of 100:1 and accuracy of ±1 percent reading, ±0.5 percent full
scale; suitability for process temperatures from up to 121¡C to 177¡C and
pressures from 10 bar(g) to 34 bar(g); no-moving parts non-clogging thermal
mass flow sensor; and precision, lithography structured platinum RTD sensors
embedded in FCI’s equal mass small diameter, all metal thermowells.

Combined with
microprocessor electronics and precision calibration, the ST51 achieves
excellent accuracy with a fast response, and requires virtually no maintenance over
its lifetime for an exceptionally low lifecycle cost. The ST51 meter’s
electronics are housed in a rugged IP67 rated enclosure with dual conduit ports
in either NPT or M20 threading. The instrument comes standard with dual 4-20 mA
outputs and a 500 Hz pulse output.

Optional features include
HART as well as a higher process temperature service range, NAMUR compliant
4-20 mA outputs and a SIL compliance rating. The transmitter/electronics can be
integrally mounted with the flow element (probe) or remote mounted to best
match the installation requirements.

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

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