Saturday, April 21, 2018

Infrared Pyrometry Keeps an "Eye On" the Health of Combustion Chambers in Power Generation Boilers

Williamson Infrared Pyrometer
Williamson Infrared Pyrometer
Fossil fuel power plants generate electricity by spinning a generator turbine with pressurized steam. The steam is created by heat exchanger tubes in a combustion chamber. The combustion flame heats the air, which heats the exchanger tubes, which in turn heats water in the boiler creating steam.

The more quickly steam is created, the faster the turbines turn, which produces more electricity. The efficiency by which steam is produced is proportional to the amount of heat created in the combustion chamber, and the transfer rate of the heat in to the exchanger tubes.

Maintaining the temperatures of the combustion chamber is critical. It needs to be carefully controlled. Exceeding the temperature thresholds of the refractory brick and the heat exchanger tubes has serious implications.  Refractory materials will vitrify (glass over) when overheated and lose their insulating properties. Heat exchanger tubes will fatigue when heated above their design limits, and will soften and crack. Costly downtime and unscheduled maintenance will result.

A result of combustion is the accumulation of soot and fly ash build-up on the heat exchanger tubes. This accumulation significantly decreases the efficiency of heat transfer. As less heat is transferred to the inside the boiler tube, steam production is reduced, and the tube's external temperature rises. A characteristic of fly ash is that, as temperatures increase, it gets stickier. As it sticks, it builds up more quickly. This is obviously a problem. The rate of build-up can be slowed by controlling fly ash temperature, and therefore optimum heat exchanger efficiency can be optimized.

The manufacturer Williamson successfully applies their short-wavelength pyrometers to measure refractory wall and heat exchanger tube temperature to protect and ensure efficient operation. With these pyrometers plant operators can also determine when boiler tubes need to be cleaned. Another Williamson dual-wavelength pyrometer is used to monitor fly ash temperature near the bottom of the heat exchanger tubes, and also to measure flame temperatures within the firebox.

Benefits:
  • Improved process efficiency.
  • Uniform bed temperature.
  • Protects against catastrophic damage.

For more information on non-contact temperature measurement or Williams infrared pyrometers visit https://hilealabama.com or call 800-536-0269.