Infrared measurement of high-temperature flue temperature in boilers

　　The current pneumatic temperature of boilers is measured mainly by thermoelectric dolls, smoke-temperature probes and traditional infrared thermometers, all of which suffer from deficiencies:

　　Owing to the extent and accuracy of the thermoelectric doll measurements, the pneumatic temperature of the boiler generally does not have a temperature measuring device in place prior to the high temperature reheater. Operators do not visualize and monitor the combustion in the furnace and the pneumatic vents. The absence of temperature measurements and the inadequate functioning of some of the combustion optimization systems used by the boilers have had some impact on further improving the efficiency of the boiler and the reliability of the equipment.

　　The inertity of the thermoelectric doll keeps the indicator values of the instrument behind the measured temperature change, which is less sensitive than the actual flue gas temperature change because of the lag in the temperature fluctuations detected by the thermoelectric dolls, which are less amplified than the smoke temperature fluctuations; Due to environmental and structural constraints in the use of thermoelectric dolls, many factors, such as wear and tear, result in shortcomings such as short operational life and maintenance problems.

　　Thermal voltage is placed on the side of the furnace wall, affected by penetration depths, and it is impossible to measure the temperature of the pneumatic space, which varies from 5 to 10 per cent from centre to edge, while thermal voltage protection tube is reduced by 5 to 10 per cent from centre to edge, focal points, salt slags lead to poor insulation between thermal electrode and the furnace wall, causing increased heat resistance and hindering heat transfer, causing not only heat and electricity loss, but also interference, resulting in temperature oscillometric values that are lower than the real values of the measured temperature, which are more severe at high temperatures and can sometimes rise to 100 degrees.

　　A smoke-temperature probe can only work for a short period of time during the start-up of the boiler, which must be recovered when the chamber temperature exceeds 570°C in order to avoid burning and prevent continuous online monitoring of the flue gas temperature; At the same time, it is constrained by the environment and structure of its use, which causes short life expectancy, uncertainty of measurement accuracy, data lag, high rate of mechanical failure and maintenance problems, including high temperature fluctuations, vibrations and installation patterns.

　　In order to protect the sensor from damage to the sensor from the high temperature smoke in the furnace, the traditional infrared thermometers install a layer of glass at the front end and rely on glass to isolate the smoke, which causes infrared wave decay and inaccuracies in temperature measurements.

　　The frequent jamming of the focus of the conventional infrared thermometers at the point of view has made it impossible to measure the flue gas accurately, and each focal point has to be removed from the equipment, which is time-consuming, labour-intensive and has a high level of maintenance.

　　Meaning of application of high-temperature pneumatic temperature infrared meters for boilers

　　All-process smoke temperature detection: The flue gas temperature in the range of 250°C ~ 1650°C can be monitored to meet the needs of the boiler for full operation and full process monitoring. In particular, coal-fired varieties are more complex, coal ash-fired melting points are more volatile, and ash-rich alkaline-metal boilers are of great importance for guiding coal-blending and combustion adjustments.

　　Large area focals in the prevention furnaces: the temperature of smoke is exported through continuous monitoring of the furnaces, the risk of condensation is determined in advance in comparison with the ash melting point of coal-fired plants, and the temperature changes in the plume in the regions where the plume is passed, above and above the high temperature reheaters can be determined by comparing the temperature changes in the plume and taking early measures to avoid large areas of condensation leading to the shutdown of the furnace.

　　Optimization of ash-blower control: Optimizing the operation of the ash-blower through accurate smoke-temperature measurements and change trends, determining the performance of the ash-blower, making an accurate determination of the ash-bightness of the furnace, and optimizing the operation of the ash-blower through experience.

　　(b) Replacement of smoke-temperature probes: Mechanical chain-driven furnaces can only work for a short period of time during the launch of the aircraft, cannot achieve continuous monitoring of the temperature of the smoke online, and use a heavy, high maintenance volume and low reliability. Infrared smoke thermometers allow continuous, real-time, accurate and reliable measurements of smoke temperature from the furnace.

　　Monitoring of the flame centre: The installation of two infrared furnace chamber thermometers on the walls on both sides of the boiler will be effective in determining whether the centre position of the flame is tilted and contributing to the combustion adjustment.

　　Reduced combustion material consumption at start-up: By accurately measuring the flue gas temperature, accurately controlling the temperature increase rate of the boiler, achieving rapid, safe start of the boiler and reducing material consumption.

　　Low nitrogen oxides application: In the Selective Non-Tanger Reduction (SNCR) system, the temperature "window" between 870°C ~1150°C is monitored to add urea or ammonia to the low nitrogen oxides booster.

　　Description of the product of the high-temperature pneumatic temperature infrared measuring machine for boilers

　　The high-temperature flue temperature infrared meter of the boiler is a new type of product that can be used as a substitute for the accurate detection of the temperature of the flue gas in the furnace by traditional thermoelectric dolls or smoke thermometers. It has the characteristics of continuous, real-time, accurate, reliable, non-contact, rapid response time, safety of use, long life, measurable space smoke temperature, etc.

　　The product has a protective cooling kit, which can be fitted with any hole, door, light equipment and convenient installation in the boiler by flange; Specially designed air cooling and blow-cleaning systems to ensure reliable and stable operation of the equipment in high temperatures and to effectively prevent focal points; A specially designed rapid-focusing system allows for quick handling of focal points when needed. User access will require only compressed air and two-wire shielded signal cables.

　　Specification parameters for an infrared measuring device for high-temperature flue temperature in boilers

Measurement range ：250℃~1650℃， You can also select the scale by 120℃~1650℃

　　Measurement accuracy: ±1%; temperature resolution: 0.1°C

　　Repeatability: ±0.5%; emissivity: 0.1–1.0

　　Response time: 165 ms

　　Infrared spectroscopy reaction: Thermal CO2

Electricity ：24VDC，500mA，（DCS Provision 4~20mA The power circuit. ）

Data Output ：24V，4-20mA，HART

Working temperature ： Not greater than 120℃

　　Shell: 304 stainless steel, protection level: IP65

　　Refrigeration mode: empty cold, clean compressed air, 0.5 m3/h

　　Compressed air: not less than 0.6 MPa

Length ：50cm Weight ：10kg