Mass flowmeter optimized for biofuels applications

Growing numbers of biogas and methane recovery sites can monitor collection systems with FCI mass flowmeter. See photo. Link to product research.
By Control Engineering Staff February 19, 2009

This design can be calibrated to the user
Fluid Components International
(FCI) has released its new ST51 mass flowmeter designed for biogas production and methane capture and recovery systems. The explosion-proof configuration features easy installation and low maintenance.

“This flow meter is designed specifically to solve the unique challenges to flow metering in bioprocess generated methane,” says Randy Brown, marketing manager for FCI. “It features a no-moving-parts design that’s non-clogging and operates over a wide flow range with low-flow sensitivity. It’s packaged in an explosion-proof transmitter, and the calibration is matched to the user’s actual gas composition and installation conditions.”

Measuring flow of wet, dirty biogas generated by an anaerobic digester is difficult. Typically, it’s a dangerous mixture comprising methane (CH 4 ), carbon dioxide (CO 2 ), and water vapor with smaller percentages of hydrogen sulfide (H 2 S) and other gases. The wetness, H 2 S and other particulates create a corrosive condensate on pipe walls and instruments. The gas flow varies widely based on fluctuating plant process demands and seasonal variations in temperature and humidity.

A thermal mass, insertion-style flow element gives the ST51 flow accuracy toin wastewater treatment. It operates at temperatures from 0 to 250 °F (-18 to 121 °C) and withstands pressures up to 500 psi.

How little maintenance?
FCI says the flow sensing element has no moving parts and no orifices to clog or foul. This helps provide virtually maintenance-free service in this problem application. The transmitter includes built-in temperature compensation circuitry for accurate, repeatable measurements year-round as temperatures rise and fall seasonally.

The flow element is constructed with a 316L stainless steel body and Hastelloy C-22 thermowell sensors to resist corrosion. It has broad approvals for use in hazardous environments. The ST51’s optional integral digital display features a two-line, 16-character LCD screen that is easy to read and can be rotated for optimum viewing and installation flexibility. The LCD screen’s top line shows flow rate, and the bottom line is user assignable for temperature readings or totalized flow.

In recent product research , survey respondents identified reliability, accuracy, and calibration ease as very important in flowmeter selection.

—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com ,
Control Engineering Process Instrumentation & Sensors Monthly
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