Economic Evaluation of Drying of Soot Sludge and Sawdust Mixture at Low Temperatures Using the Characteristic Drying Curve Method

Soot sludge is a waste stream formed in the fuel oil gasification of formic acid and hydrogen peroxide production. The soot sludge has a high moisture content (95%) and is presently combusted with heavy fuel oil in order to dispose of the sludge. Experimental tests earlier conducted by the authors h...

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Main Authors: Tiina Myllymaa, Henrik Holmberg, Pekka Ahtila
Format: Article
Language:English
Published: MDPI AG 2020-01-01
Series:ChemEngineering
Subjects:
Online Access:https://www.mdpi.com/2305-7084/4/1/6
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author Tiina Myllymaa
Henrik Holmberg
Pekka Ahtila
author_facet Tiina Myllymaa
Henrik Holmberg
Pekka Ahtila
author_sort Tiina Myllymaa
collection DOAJ
description Soot sludge is a waste stream formed in the fuel oil gasification of formic acid and hydrogen peroxide production. The soot sludge has a high moisture content (95%) and is presently combusted with heavy fuel oil in order to dispose of the sludge. Experimental tests earlier conducted by the authors have shown that the sludge can be convectively dried with sawdust in a fixed bed. By upgrading the sludge from waste to fuel, the utilization of oil can be decreased. In this study, characteristic drying curves (CDC) are determined for the sludge and sawdust mixture. The CDCs are further used to evaluate the economy of the mixture drying in a belt dryer by using the payback period method. Results show that the linear CDCs of the mixture can be used to extrapolate drying data from specific drying conditions to another when the bed height is 200 or 300 mm, and the inlet air temperature 40−100 °C. The economic analysis shows that drying is economical for all inlet air temperatures if the oil price is ≥350 €/t-oil. Sensitivity analyses reveal that the heat, sawdust and emission prices have no remarkable influence on the economy of drying if the oil price does not fall below c. 300 €/t-oil.
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spelling doaj.art-fdc004f5cac04ab8a7e0ff8c2b9c98da2022-12-21T18:39:57ZengMDPI AGChemEngineering2305-70842020-01-0141610.3390/chemengineering4010006chemengineering4010006Economic Evaluation of Drying of Soot Sludge and Sawdust Mixture at Low Temperatures Using the Characteristic Drying Curve MethodTiina Myllymaa0Henrik Holmberg1Pekka Ahtila2Department of Mechanical Engineering, School of Engineering, Aalto University, Sähkömiehentie 4 J, P.O. Box 14400, FI-00076 Aalto, FinlandDepartment of Mechanical Engineering, School of Engineering, Aalto University, Sähkömiehentie 4 J, P.O. Box 14400, FI-00076 Aalto, FinlandDepartment of Mechanical Engineering, School of Engineering, Aalto University, Sähkömiehentie 4 J, P.O. Box 14400, FI-00076 Aalto, FinlandSoot sludge is a waste stream formed in the fuel oil gasification of formic acid and hydrogen peroxide production. The soot sludge has a high moisture content (95%) and is presently combusted with heavy fuel oil in order to dispose of the sludge. Experimental tests earlier conducted by the authors have shown that the sludge can be convectively dried with sawdust in a fixed bed. By upgrading the sludge from waste to fuel, the utilization of oil can be decreased. In this study, characteristic drying curves (CDC) are determined for the sludge and sawdust mixture. The CDCs are further used to evaluate the economy of the mixture drying in a belt dryer by using the payback period method. Results show that the linear CDCs of the mixture can be used to extrapolate drying data from specific drying conditions to another when the bed height is 200 or 300 mm, and the inlet air temperature 40−100 °C. The economic analysis shows that drying is economical for all inlet air temperatures if the oil price is ≥350 €/t-oil. Sensitivity analyses reveal that the heat, sawdust and emission prices have no remarkable influence on the economy of drying if the oil price does not fall below c. 300 €/t-oil.https://www.mdpi.com/2305-7084/4/1/6carbon blackcarbon sootcharacteristic drying curveconstant drying curvepayback period
spellingShingle Tiina Myllymaa
Henrik Holmberg
Pekka Ahtila
Economic Evaluation of Drying of Soot Sludge and Sawdust Mixture at Low Temperatures Using the Characteristic Drying Curve Method
ChemEngineering
carbon black
carbon soot
characteristic drying curve
constant drying curve
payback period
title Economic Evaluation of Drying of Soot Sludge and Sawdust Mixture at Low Temperatures Using the Characteristic Drying Curve Method
title_full Economic Evaluation of Drying of Soot Sludge and Sawdust Mixture at Low Temperatures Using the Characteristic Drying Curve Method
title_fullStr Economic Evaluation of Drying of Soot Sludge and Sawdust Mixture at Low Temperatures Using the Characteristic Drying Curve Method
title_full_unstemmed Economic Evaluation of Drying of Soot Sludge and Sawdust Mixture at Low Temperatures Using the Characteristic Drying Curve Method
title_short Economic Evaluation of Drying of Soot Sludge and Sawdust Mixture at Low Temperatures Using the Characteristic Drying Curve Method
title_sort economic evaluation of drying of soot sludge and sawdust mixture at low temperatures using the characteristic drying curve method
topic carbon black
carbon soot
characteristic drying curve
constant drying curve
payback period
url https://www.mdpi.com/2305-7084/4/1/6
work_keys_str_mv AT tiinamyllymaa economicevaluationofdryingofsootsludgeandsawdustmixtureatlowtemperaturesusingthecharacteristicdryingcurvemethod
AT henrikholmberg economicevaluationofdryingofsootsludgeandsawdustmixtureatlowtemperaturesusingthecharacteristicdryingcurvemethod
AT pekkaahtila economicevaluationofdryingofsootsludgeandsawdustmixtureatlowtemperaturesusingthecharacteristicdryingcurvemethod