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Thermal Probe ReplacementAn acoustic pyrometer provides a practical and cost-effective solution for on-line continuous gas temperature measurements within hostile furnace and boiler environments. Thermal probes require that a mechanical means be employed to retract the temperature sensor, once the probe maximum temperature limit has been reached (typically 1000o F without cooling air). An acoustic pyrometer, on the other hand, can be installed such that the furnace gas temperature (ambient to 3000o F) can be measured from initial start-up to full load conditions. It is also possible to use the data from the acoustic pyrometer temperature reading to manage the firing rate from start-up through the full operating range to avoid hot sections in the superheater. This would provide for superheater protection through the entire load range by utilizing upstream information to manage the type temperatures.
One of the limitations of earlier acoustic pyrometers has been associated with the high level of combustion and soot blower noise typically found in a large gas/oil fired utility boiler. This noise has in the past, adversely affected the overall operation reliability of an acoustic pyrometer system. However, recent breakthroughs in acoustic pyrometry and digital signal processing have now resulted in a system that is very robust and can operate in the high noise levels found in large coal, gas and oil-fired utilities. 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 temperature in the boiler then increases while the boiler efficiency decreases. With continuous temperature measurements, the Acoustic Pyrometer can give you the data required to keep the boiler running at maximum efficiency.
The output is a 4-20 mA signal for each path, for easy connection to process control, plant DCS, or meter. With the SP-2 system, the average and difference are also available as 4-20 mA signals.
Following the features section is a screen shot showing an actual temperature graph of the SP-1, our one path system.SEI Acoustic Pyrometer Features
- Eliminate HTV intensive parts replacement and the high maintenance.
- Non-Intrusive rugged design: Stainless Steel Waveguides are outside the furnace or boiler wall.
- Can be beneficial for soot blower control. (See also Soot Blower Control)
- Suitable for all fuels.
- The system’s lower range is 35o F, or 0o C, and the system may be used for cold or warm start-ups.
- The upper temperature range is 3500o F, or nearly 2000o C.
- Linear and Accurate over the entire temperature range.
- Fault Tolerant Processor Control Unit (PCU).
- 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.
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.
See also "Application of Acoustic Pyrometry as a Replacement
for Thermal Probes in large Gas & Oil Fired Utility Boilers"
on our literature
page.
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