Acoustic Pyrometers & Furnace Exit Gas Temperature, FEGT.

Applications

FEGT

Furnace Exit Gas Temperature (FEGT) measurements within hostile furnace and boiler environments have been provided by SEI for over fifteen years. Our acoustic pyrometer provides a practical and cost-effective solution for on-line continuous monitoring.

After years of power plant installations, we have improved our temperature measuring capabilities again in 2001, to overcome most sootblower noise.

Combustion gas temperatures inside a modern power boiler furnace can reach nearly 3000^o F (1650^o C), rendering conventional thermocouple and water-cooled thermal probe methods effectively useless. The acoustic pyrometer is the only instrument that can offer reliable, accurate, and repeatable measurement of high furnace exit gas temperatures on an automatic unattended basis.

Boiler efficiency depends on good heat transfer rates between the fire and boiler tubes. As the tubes become more laden with soot, less heat is absorbed in the tubes. The FEGT then increases while the boiler efficiency decreases. Continuous monitoring of the FEGT and Power Output alerts the operator to start soot blowing based on real time information.

The SEI Acoustic Pyrometer temperature is automatically calculated by our system many times a minute for constant monitoring. The output is a 4-20 mA signal for easy connection to process control.

Following the features section is a screen shot showing an actual temperature graph of the SP-1, our one path system over a 17 hour period.

SEI Acoustic Pyrometer Features

Eliminate HTV intensive parts replacement and the high maintenance.
Non-Intrusive rugged design: Stainless Steel Waveguides are outside the furnace wall.
Can be beneficial for soot blower control. (See also Soot Blower Control)
Suitable for all fuels.
The system’s lower range is 35^o F, and allows the system to be used for cold or warm start-ups.
The upper temperature range is 3500^o F, or nearly 2000^o C.
Linear and Accurate over the entire temperature range.
Fault Tolerant Processor Control Unit (PCU).
The 4-20 mA temperature output is of the path; and with two paths the average, and difference are also available. Any or all outputs easily connect to the computer system for ISB control.
RS-232 and RS-422 for local monitoring and statistics through local PC.
Telephone modem for remote monitoring.
An EEPROM stores all program settings.
Automatic recovery after power loss.
Remote enable/disable input
All Software operates on Windows 95/98/2000/XP or NT operating systems, and is included with each system.

SP-1 Actual temperature graph, 640 MW, Coal Fired, Base Load Unit

Actual 17 hour Graph and Statistics at a Large Power Boiler

Realizing equipment failure raises energy costs, increases labor costs; while production and profit margin decrease, our equipment is designed and built to the highest industry standard.

Sound waves can be used to measure the temperature of a gas, including air, using our Boilerwatch^®MMP Systems. Boilerwatch^®MMP Systems can also be used for multiple paths, contour maps, and temperature distribution mapping. The MMP comes with the TMS-2000 software mentioned above.

For measurement of gas temperature in a boiler the distance between the acoustic transmitter and receiver is fixed and easily measured, and the flight time is measured by the acoustic pyrometer. From this information, the average gas temperature across the path is computed. For the complete theory, see The Technology.

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