Temperature gradient induced changes within superheater ash deposits high in chlorine

Roland Balint; Markus Engblom; Jonne Niemi; Daniel Silva da Costa; Daniel Lindberg; Patrik Yrjas; Leena Hupa; Mikko Hupa

doi:10.1016/j.energy.2021.120439

Temperature gradient induced changes within superheater ash deposits high in chlorine

Roland Balint^*
, Markus Engblom
, Jonne Niemi
, Daniel Silva da Costa
, Daniel Lindberg
, Patrik Yrjas
, Leena Hupa
, Mikko Hupa

^*Corresponding author for this work

Research output: Contribution to journal › Article › Scientific › peer-review

13 Citations (Scopus)

Abstract

Cross-sections of kraft recovery boiler superheater deposits were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The observed deposit morphology can be explained by temperature gradient induced time-dependent processes such as diffusional transport of alkali chloride vapours, temperature gradient zone melting, formation of melt enriched in Cl and K, and movement of this enriched melt towards the steel. These processes have recently been identified on a laboratory scale under well-controlled conditions, and are now for the first time identified to take place also in actual boiler superheater deposits. The identified processes alter the local deposit composition and melting behaviour close to the steel. The local first melting temperature (T₀) close to the steel is lower by 30 °C compared to that of the deposit bulk T₀. The observations made in this work give new insight into the melting and ageing behaviour of superheater deposits, relevant for superheater corrosion.

Original language	English
Article number	120439
Journal	Energy
Volume	226
DOIs	https://doi.org/10.1016/j.energy.2021.120439
Publication status	Published - 1 Jul 2021
MoE publication type	A1 Journal article-refereed

Funding

The financing through a research grant awarded by the Fortum Foundation (Application 20190123 ) is highly acknowledged. This work is part of the project Clean and efficient utilization of demanding fuels (CLUE), with support from the industrial partners: ANDRITZ, Fortum, International Paper , UPM-Kymmene Corporation, and Valmet Technologies Oy, as part of the activities of the Åbo Akademi University Johan Gadolin Process Chemistry Centre. Additional support from the Academy of Finland project “Understanding the dynamics of intradeposit chemistry and morphology for control of corrosion in high temperature processes” (Decision 310266) is highly appreciated. We want to thank Linus Silvander for carrying out SEM/EDX analyses. The financing through a research grant awarded by the Fortum Foundation (Application 20190123) is highly acknowledged. This work is part of the project Clean and efficient utilization of demanding fuels (CLUE), with support from the industrial partners: ANDRITZ, Fortum, International Paper, UPM-Kymmene Corporation, and Valmet Technologies Oy, as part of the activities of the ?bo Akademi University Johan Gadolin Process Chemistry Centre. Additional support from the Academy of Finland project ?Understanding the dynamics of intradeposit chemistry and morphology for control of corrosion in high temperature processes? (Decision 310266) is highly appreciated. We want to thank Linus Silvander for carrying out SEM/EDX analyses.

Keywords

Ageing mechanism
Melt enrichment
Superheater deposit
Temperature gradient

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10.1016/j.energy.2021.120439Licence: CC BY

Cite this

@article{0341d296468249fd982d0a1c9407d3a4,

title = "Temperature gradient induced changes within superheater ash deposits high in chlorine",

abstract = "Cross-sections of kraft recovery boiler superheater deposits were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The observed deposit morphology can be explained by temperature gradient induced time-dependent processes such as diffusional transport of alkali chloride vapours, temperature gradient zone melting, formation of melt enriched in Cl and K, and movement of this enriched melt towards the steel. These processes have recently been identified on a laboratory scale under well-controlled conditions, and are now for the first time identified to take place also in actual boiler superheater deposits. The identified processes alter the local deposit composition and melting behaviour close to the steel. The local first melting temperature (T0) close to the steel is lower by 30 °C compared to that of the deposit bulk T0. The observations made in this work give new insight into the melting and ageing behaviour of superheater deposits, relevant for superheater corrosion.",

keywords = "Ageing mechanism, Melt enrichment, Superheater deposit, Temperature gradient",

author = "Roland Balint and Markus Engblom and Jonne Niemi and \{Silva da Costa\}, Daniel and Daniel Lindberg and Patrik Yrjas and Leena Hupa and Mikko Hupa",

note = " Funding Information: The financing through a research grant awarded by the Fortum Foundation (Application 20190123) is highly acknowledged. This work is part of the project Clean and efficient utilization of demanding fuels (CLUE), with support from the industrial partners: ANDRITZ, Fortum, International Paper, UPM-Kymmene Corporation, and Valmet Technologies Oy, as part of the activities of the ?bo Akademi University Johan Gadolin Process Chemistry Centre. Additional support from the Academy of Finland project ?Understanding the dynamics of intradeposit chemistry and morphology for control of corrosion in high temperature processes? (Decision 310266) is highly appreciated. We want to thank Linus Silvander for carrying out SEM/EDX analyses. Publisher Copyright: {\textcopyright} 2021 The Authors",

year = "2021",

month = jul,

day = "1",

doi = "10.1016/j.energy.2021.120439",

language = "English",

volume = "226",

journal = "Energy",

issn = "0360-5442",

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TY - JOUR

T1 - Temperature gradient induced changes within superheater ash deposits high in chlorine

AU - Balint, Roland

AU - Engblom, Markus

AU - Niemi, Jonne

AU - Silva da Costa, Daniel

AU - Lindberg, Daniel

AU - Yrjas, Patrik

AU - Hupa, Leena

AU - Hupa, Mikko

N1 - Funding Information: The financing through a research grant awarded by the Fortum Foundation (Application 20190123) is highly acknowledged. This work is part of the project Clean and efficient utilization of demanding fuels (CLUE), with support from the industrial partners: ANDRITZ, Fortum, International Paper, UPM-Kymmene Corporation, and Valmet Technologies Oy, as part of the activities of the ?bo Akademi University Johan Gadolin Process Chemistry Centre. Additional support from the Academy of Finland project ?Understanding the dynamics of intradeposit chemistry and morphology for control of corrosion in high temperature processes? (Decision 310266) is highly appreciated. We want to thank Linus Silvander for carrying out SEM/EDX analyses. Publisher Copyright: © 2021 The Authors

PY - 2021/7/1

Y1 - 2021/7/1

N2 - Cross-sections of kraft recovery boiler superheater deposits were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The observed deposit morphology can be explained by temperature gradient induced time-dependent processes such as diffusional transport of alkali chloride vapours, temperature gradient zone melting, formation of melt enriched in Cl and K, and movement of this enriched melt towards the steel. These processes have recently been identified on a laboratory scale under well-controlled conditions, and are now for the first time identified to take place also in actual boiler superheater deposits. The identified processes alter the local deposit composition and melting behaviour close to the steel. The local first melting temperature (T0) close to the steel is lower by 30 °C compared to that of the deposit bulk T0. The observations made in this work give new insight into the melting and ageing behaviour of superheater deposits, relevant for superheater corrosion.

AB - Cross-sections of kraft recovery boiler superheater deposits were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The observed deposit morphology can be explained by temperature gradient induced time-dependent processes such as diffusional transport of alkali chloride vapours, temperature gradient zone melting, formation of melt enriched in Cl and K, and movement of this enriched melt towards the steel. These processes have recently been identified on a laboratory scale under well-controlled conditions, and are now for the first time identified to take place also in actual boiler superheater deposits. The identified processes alter the local deposit composition and melting behaviour close to the steel. The local first melting temperature (T0) close to the steel is lower by 30 °C compared to that of the deposit bulk T0. The observations made in this work give new insight into the melting and ageing behaviour of superheater deposits, relevant for superheater corrosion.

KW - Ageing mechanism

KW - Melt enrichment

KW - Superheater deposit

KW - Temperature gradient

UR - https://www.scopus.com/pages/publications/85103401578

U2 - 10.1016/j.energy.2021.120439

DO - 10.1016/j.energy.2021.120439

M3 - Article

AN - SCOPUS:85103401578

SN - 0360-5442

VL - 226

JO - Energy

JF - Energy

M1 - 120439

ER -

Temperature gradient induced changes within superheater ash deposits high in chlorine

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Keywords

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