Further evaporation and final treatment of process-water concentrates

Paterson McKeough, Leena Fagernäs

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)

Abstract

The study is part of a longer-term effort aimed at developing a separate treatment process for evaporation-concentrates of paper-mill process waters. This article deals with research on the two key processing steps; namely, the further evaporation and the final treatment of the concentrates. In laboratory expenments, various feed waters, including several different TMP filtrates, were evaporated to high dry-solids contents. The condensates recovered in most experiments contained relatively small amounts of organic matter. The extent of vapourisation of organic acids, relative to water, increased somewhat with increase in dry-solids content. Two TMP concentrates from large-scale evaporation plants were further concentrated in a pilot. scale forced-circulation evaporator. Viscosity was the factor limiting the extent of concentration. Using an evaporation temperature of about 80°C, the maximum dry-solids contents achieved with the two different concentrates were about 45 wt% and about 60 wt%, respectively. Fouling of heat-transfer surfaces was observed with both concentrates. A techno-economic evaluation of final-treatment options for alkali-rich concentrates is under way. According to intermediate results, molten-phase combustion processes would not require support fuel once the dry-solids content of TMP concentrate exceeds about 50 wt%. The aim of future work is to optimise the overall treatment process.
Original languageEnglish
Pages (from-to)25-32
Number of pages8
JournalWater Science and Technology
Volume40
Issue number11-12
DOIs
Publication statusPublished - 1999
MoE publication typeA1 Journal article-refereed

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Evaporation
evaporation
Water
vaporization
Organic acids
Evaporators
Fouling
condensate
Vaporization
organic acid
fouling
Biological materials
limiting factor
heat transfer
Molten materials
mill
viscosity
combustion
Viscosity
Heat transfer

Cite this

McKeough, Paterson ; Fagernäs, Leena. / Further evaporation and final treatment of process-water concentrates. In: Water Science and Technology. 1999 ; Vol. 40, No. 11-12. pp. 25-32.
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title = "Further evaporation and final treatment of process-water concentrates",
abstract = "The study is part of a longer-term effort aimed at developing a separate treatment process for evaporation-concentrates of paper-mill process waters. This article deals with research on the two key processing steps; namely, the further evaporation and the final treatment of the concentrates. In laboratory expenments, various feed waters, including several different TMP filtrates, were evaporated to high dry-solids contents. The condensates recovered in most experiments contained relatively small amounts of organic matter. The extent of vapourisation of organic acids, relative to water, increased somewhat with increase in dry-solids content. Two TMP concentrates from large-scale evaporation plants were further concentrated in a pilot. scale forced-circulation evaporator. Viscosity was the factor limiting the extent of concentration. Using an evaporation temperature of about 80°C, the maximum dry-solids contents achieved with the two different concentrates were about 45 wt{\%} and about 60 wt{\%}, respectively. Fouling of heat-transfer surfaces was observed with both concentrates. A techno-economic evaluation of final-treatment options for alkali-rich concentrates is under way. According to intermediate results, molten-phase combustion processes would not require support fuel once the dry-solids content of TMP concentrate exceeds about 50 wt{\%}. The aim of future work is to optimise the overall treatment process.",
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Further evaporation and final treatment of process-water concentrates. / McKeough, Paterson; Fagernäs, Leena.

In: Water Science and Technology, Vol. 40, No. 11-12, 1999, p. 25-32.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Further evaporation and final treatment of process-water concentrates

AU - McKeough, Paterson

AU - Fagernäs, Leena

PY - 1999

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AB - The study is part of a longer-term effort aimed at developing a separate treatment process for evaporation-concentrates of paper-mill process waters. This article deals with research on the two key processing steps; namely, the further evaporation and the final treatment of the concentrates. In laboratory expenments, various feed waters, including several different TMP filtrates, were evaporated to high dry-solids contents. The condensates recovered in most experiments contained relatively small amounts of organic matter. The extent of vapourisation of organic acids, relative to water, increased somewhat with increase in dry-solids content. Two TMP concentrates from large-scale evaporation plants were further concentrated in a pilot. scale forced-circulation evaporator. Viscosity was the factor limiting the extent of concentration. Using an evaporation temperature of about 80°C, the maximum dry-solids contents achieved with the two different concentrates were about 45 wt% and about 60 wt%, respectively. Fouling of heat-transfer surfaces was observed with both concentrates. A techno-economic evaluation of final-treatment options for alkali-rich concentrates is under way. According to intermediate results, molten-phase combustion processes would not require support fuel once the dry-solids content of TMP concentrate exceeds about 50 wt%. The aim of future work is to optimise the overall treatment process.

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DO - 10.1016/S0273-1223(99)00697-6

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