Flow Meters Application in Thermal Power Plants

Thermal power plants (heat-engine plants) are extremely complex industrial systems, and their stable, efficient, and safe operation relies highly on a large number of accurate measuring instruments. Flow meters play an important role in it, and their accuracy is directly related to the power plant's economy, environmental friendliness, and safety.

Flow rate is one of the most important process parameters in thermal power plants. It is used to calculate efficiency, control load, and ensure safety.

1) Steam Flow Measurement

This is the most important parameter for power plants in calculating power generation efficiency, thermal efficiency, and coal consumption. Accurate steam flow measurement is the basics of power plant economic analysis. It is also used for turbine load control and safety Protection. For example, a sudden abnormal increase or decrease in flow rate may indicate a pipeline rupture or equipment failure.

Standard throttling devices (orifice plates) paired with differential pressure transmitters remain the mainstream choice due to their high reliability, wide applicability, and international standard support. In addition, balanced flow meters and vortex flow meters are also commonly used for measuring medium and low-pressure steam.

2) Water Supply Flow Measurement

The three-impulse control of boiler drum water level (which works in conjunction with steam flow and drum water level) is a core parameter for ensuring safe boiler operation. The balance between feed-water flow and main steam flow directly reflects the boiler's operating status.

Standard throttling devices (orifice plates or nozzles) are dominant. For large-diameter water supply pipelines, ultrasonic flow meters and electromagnetic flow meters are also being used more and more widely.

3) Fuel and Gas Flow Measurement

Used for calculating fuel consumption, cost accounting, and combustion control.

For fuel oil, Coriolis mass flow meters are commonly used because they can directly measure mass flow rate and are not affected by changes in temperature and density.

4) Chemical Water Treatment Flow Measurement

Control the dosage of chemicals in the water treatment process to ensure water quality and prevent equipment corrosion and scaling.

Electromagnetic flow meters are the mainly popular because they are suitable for various conductive liquids, corrosion-resistant, non-clogging, and have low pressure loss.

5) Air/Flue Gas Flow Measurement

Used for combustion control optimization (air-to-coal ratio) to ensure complete combustion and reduce pollutant generation. In environmental protection, it is used to calculate total pollutant emissions (such as SO ₂ and NOx), which is a mandatory requirement for environmental monitoring.

The large size, low flow velocity, and short straight pipe section of air flue bring significant measurement challenges. Velocity-averaging tube flow meters (Annubar/ Verabar) and thermal gas mass flow meters are commonly used. In the flue gas field, non-contact ultrasonic flow meters are widely applied due to their ability to withstand high  temperatures, high dust levels, and corrosive environments.