What Are Flue Gases?

Flue gas (sometimes called exhaust gas or flue gas) is the gas from combustion plants that contains the reaction products of fuel and combustion air, as well as residual substances such as particulate matter (dust), sulfur oxides, nitrogen oxides, and carbon monoxide. Such gases are sources of potential heat energy or light energy that can be readily transmitted and distributed through pipes from the point of origin directly to the place of consumption

Its components are nitrogen, carbon dioxide, oxygen, water vapor and sulfide, etc., without pollutants accounting for more than 99%; the content of dust, powder slag and sulfur dioxide are less than 1%, which must be emptied after treatment by a gas purification device to reduce environmental impact Pollution.

Flue gas emission monitoring is essential 

Most flue gas generally contains pollutants, flue gas emissions are restricted by strict environmental regulations. Power plants need to monitor and control emissions. Flue gas emissions monitoring can also improve process efficiency. In some application environments, can also improve operational efficiency and reduce production costs. At the same time, it can also reduce the damage to the factory by emissions, thereby extending the life of the equipment.

Flue gas measurement is not easy to make it 

  • The flue gas flow rate is slow and unstable, requires the flow technology can reach a very low velocity and wide turndown ratio.

  • Pipes of flue gas normally in big size that limits to us inline connection flow meters.

  • The flue gas also contains corrosive impurities such as sulfide, others like pitot tube flow meter are very easy to be blocked.

Flue gas measurement with thermal mass flow meter

A Thermal mass flow meter working relies on the thermal dispersion technology (i.e. Mass flow computed by calculate the temperature differential or by count the currents gives on the sensor). Thermal mass flow meter does not require any pressure compensation for accurate flow measurement in gas applications.

Thermal mass flow meters provide a flue gas flow measuring solution that is accurate, repeatable, easy to install and requires virtually no maintenance.

thermal mass flow meter working theory

Comate TGF600

The two thermowell protected platinum RTD temperature sensors in the process stream. Ta is to measure the temperature of the medium, and heated the Tv with consistent current as a velocity sensor. Then analyze the temperature difference between Tv and Ta= △T. The temperature differential between these two sensors is measured and is directly proportional to the mass flow rate of the fluid.

Comate constant heating current technique provides superior accuracy and repeatability in moist flue gas measurement applications. Since CHC provides a light heating effect which actually dries condensate moisture off the sensor to ensure stable readings and performance. The alternative thermal dispersion technique, constant temperature differential, can read erratically in moist gas applications, and once sensors stacked with duty particulates. To keeping the constant temperature then sensor will hold much current and shows zero-off.

The TGF600 model which is ideal for flue gas measurement and with 1.5% of reading, offers 0.3% repeatability. This insertion type support from 1’’~ 80’’ pipes, and high temperature up to 450degrC, pressure at 63bar applications.

  • Rugged structure ensures long service life in extreme conditions

  • Very easy to install and required no maintenance to provide worry-free continuous operation

  • No moving parts to clog or foul in the presence of wet, dirty gases, as well as special materials available to resist corrosion

  • Low flow sensitivity with wide turndowns to accommodate variable gas flows

TGF600 for flue gas measurement

Flow metering applications include:

1, Primary Air/ Secondary Air
2, Fuel air flow
3, Exhaust/emissions flow