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Soot Blower ControlAn acoustic pyrometer provides a practical and cost-effective solution for on-line continuous gas temperature measurements within hostile furnace and boiler environments. After many 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 3000o F (1650o 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 gas temperatures on an automatic unattended basis.
Boiler efficiency depends on good heat transfer rates. The transfer rate is improved by blowing gas on heat transfer surfaces to remove the combustion buildup (soot blowing). It has been found that soot blowing losses can vary a great deal depending on the operator and type of coal burned. Excessive use of soot blowers creates a cost burden on a utility. The cost is incurred using parasitic power from the generating unit. If Steam is the blowing medium, less steam flow is available to the generator’s steam turbine, causing less power to be produced. Some have estimated sootblowing costs for a 415 MW unit between $1 million and $2 million per year, in addition to boiler efficiency losses. Optimizing soot blowing strategies is of value.
Gas temperature measurements can be used as a direct indication
of soot buildup, by installing a two path system. Two paths
could be used to determine the difference in temperature at
two areas in the furnace. As the tubes become more laden with
soot, less heat is absorbed in the tubes, and the temperature
difference decreases. The temperature difference is automatically
calculated by the SEI system several 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 a simulated temperature graph of the SP-2, our two 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 wall.
- Suitable for all fuels.
- The system’s lower range is 35o F, and allows the system to 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).
- 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.
Simulated temperature difference in 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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