Recovery Boiler Superheater Region Temperature Measurements for Fouling Prediction Development
Peltola, Niko Samu Santeri (2019)
Peltola, Niko Samu Santeri
2019
Ympäristö- ja energiatekniikka
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2019-05-27
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201905061521
https://urn.fi/URN:NBN:fi:tty-201905061521
Tiivistelmä
At Valmet, flue gas temperature field in recovery boiler superheater region has conventionally been evaluated in CFD modelling and Valmet in-house dimensioning tool, complemented by occasionally carried out temperature measurements. After the latest measurement campaign, changes in the boiler design have been made. This Master’s thesis was conducted together with a measurement campaign to obtain temperature measurement data in the latest design recovery boiler. Accurate knowledge of the flue gas temperature field has an important role in boiler design and development, such as the boiler superheater region fouling prediction. The results and conclusions of this thesis are used to develop the fouling prediction.
A temperature measurement campaign was carried out to obtain accurate measurement data. Campaign was conducted at a new Valmet recovery boiler delivery in Europe. Temperature was measured comprehensively in the superheater region with thermoelements, suction pyrometers and acoustic pyrometers. Thermoelement and suction pyrometer are conventionally used measurement devices, liable to certain inaccuracies discussed in this thesis. Acoustic pyrometer is a new measurement device in the recovery boiler with no earlier references. A key objective of this thesis was to demonstrate acoustic pyrometry in the recovery boiler to evaluate the functionality of the devices and the accuracy of the obtained flue gas temperature data.
The measurement data was utilized in boiler modelling carried out in CFD and Valmet in-house modelling tools. The superheater region flue gas temperature field and the superheater deposit distribution were modelled, and the results were compared to the measurement data.
During the measurement campaign, acoustic pyrometry was found accurate and reliable. The data obtained with the conventional measurement devices and acoustic pyrometry were in good agreement, and the data was coupled successfully to create a comprehensive understanding of the flue gas temperature field in the superheater region. In addition, the modelled temperature and deposit results obtained in the different modeling tools are in good agreement with each other and the measurement data. During the campaign, certain sootblowers in the superheater region were associated with altered flue gas flow field and increased superheated steam temperature.
This thesis presents data to show that these critical sootblowers shrink the flue gas vortex above the boiler nose, which leads to an altered flue gas flow field and improved heat transfer in the superheater region.
A temperature measurement campaign was carried out to obtain accurate measurement data. Campaign was conducted at a new Valmet recovery boiler delivery in Europe. Temperature was measured comprehensively in the superheater region with thermoelements, suction pyrometers and acoustic pyrometers. Thermoelement and suction pyrometer are conventionally used measurement devices, liable to certain inaccuracies discussed in this thesis. Acoustic pyrometer is a new measurement device in the recovery boiler with no earlier references. A key objective of this thesis was to demonstrate acoustic pyrometry in the recovery boiler to evaluate the functionality of the devices and the accuracy of the obtained flue gas temperature data.
The measurement data was utilized in boiler modelling carried out in CFD and Valmet in-house modelling tools. The superheater region flue gas temperature field and the superheater deposit distribution were modelled, and the results were compared to the measurement data.
During the measurement campaign, acoustic pyrometry was found accurate and reliable. The data obtained with the conventional measurement devices and acoustic pyrometry were in good agreement, and the data was coupled successfully to create a comprehensive understanding of the flue gas temperature field in the superheater region. In addition, the modelled temperature and deposit results obtained in the different modeling tools are in good agreement with each other and the measurement data. During the campaign, certain sootblowers in the superheater region were associated with altered flue gas flow field and increased superheated steam temperature.
This thesis presents data to show that these critical sootblowers shrink the flue gas vortex above the boiler nose, which leads to an altered flue gas flow field and improved heat transfer in the superheater region.