Thermal mass flow meters are used in combination with Continuous Emission Monitoring (CEM) systems for stack gas monitoring (flue gas) or air emission monitoring.
Stack Gas Flow Measurement
Stack gas comes from many combustion sources, including incinerators, kilns, and thermal oxidizers. A thermal oxidizer is a processing unit for air exhaust treatment and is commonly used during waste incineration. When the stack mixes with air, the exhausting gas is cool enough to be measured by a thermal mass flow meter, thereby benefiting from the device’s fast response and wide turndown. Measuring stack gas flow rate is required to calculate the overall mass of gas over time, a requirement for many environmental regulations.
Stack Gas Flow Profile
Stack flows are relatively high volume and in large stacks or ducts. A single-point measurement does not give a truly representative sample of the overall flow profile. Therefore multiple thermal flow meters are used, and the customer can average these readings in their control system. In these situations, the sensors are positioned at the point of equal areas in the stack.
Conventional versus Mass Flow Meters
Conventional flow meters are not mass flow devices; they are affected by the temperature and pressure of airflow. In contrast, Sage Prime Thermal Mass Flow Meter (or Paramount) will report the direct mass flow of flue gas emitted, and no separate temperature and pressure corrections are needed.
Stack Gas Monitoring Video
Image by Rebecca Humann from Pixabay