Engine Manufacturer Monitors Natural Gas Usage with Smart Thermal Mass Flow Meter

A major engine manufacturer has installed Sierra's Flat-Trak™ Model 780S smart thermal mass flow meters to measure natural gas usage in each of the eleven buildings on their campus. Natural gas is used for heating loads and to fire furnaces and other equipment. Because each facility is a separate profit center, fuel and utility costs are allocated by building. They must also provide an accurate usage report of natural gas to the Department of Natural Resources for PEMS (Predictive Emissions Monitoring Systems) compliance. PEMS uses furnace temperature, excess oxygen and actual boiler-operating information to calculate NOx emissions from natural gas fired boilers.

Accurate fuel flow measurements help the operator adjust boiler variables to reduce NOx emissions. The existing fuel measurement system consisted of turbine meters with ancillary pressure and temperature transducers. The utility engineers had identified several problems with this system, not the least of which was the high maintenance requirement of the turbine meters. They were looking for a replacement technology that would give them a direct reading of mass flow, reduce maintenance and fit the "footprint" of the turbine meters. A highly constrained piping system did not provide the required upstream diameters for most thermal mass meters. However, Sierra's Model 780S with built-in flow conditioning reduces this requirement to only three diameters and easily replaces the existing installation.

The meter's wide turndown provides an accurate measurement of natural gas at low and varied loads, ensuring accurate cost-allocation and improved boiler control capability. The transducer's smart electronics and field-validation capability have also simplified auditing procedures for PEMS.