Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge

Sewage sludge hydrochars (SSHs), which are produced by hydrothermal carbonization (HTC), offer a high calorific value to be applied as a biofuel. However, HTC is a complex processand the properties of the resulting product depend heavily on the process conditions and feedstock composition. In this w...

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Main Authors: Theodoros N. Kapetanakis, Ioannis O. Vardiambasis, Christos D. Nikolopoulos, Antonios I. Konstantaras, Trinh Kieu Trang, Duy Anh Khuong, Toshiki Tsubota, Ramazan Keyikoglu, Alireza Khataee, Dimitrios Kalderis
Format: Article
Language:English
Published: MDPI AG 2021-05-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/14/11/3000
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author Theodoros N. Kapetanakis
Ioannis O. Vardiambasis
Christos D. Nikolopoulos
Antonios I. Konstantaras
Trinh Kieu Trang
Duy Anh Khuong
Toshiki Tsubota
Ramazan Keyikoglu
Alireza Khataee
Dimitrios Kalderis
author_facet Theodoros N. Kapetanakis
Ioannis O. Vardiambasis
Christos D. Nikolopoulos
Antonios I. Konstantaras
Trinh Kieu Trang
Duy Anh Khuong
Toshiki Tsubota
Ramazan Keyikoglu
Alireza Khataee
Dimitrios Kalderis
author_sort Theodoros N. Kapetanakis
collection DOAJ
description Sewage sludge hydrochars (SSHs), which are produced by hydrothermal carbonization (HTC), offer a high calorific value to be applied as a biofuel. However, HTC is a complex processand the properties of the resulting product depend heavily on the process conditions and feedstock composition. In this work, we have applied artificial neural networks (ANNs) to contribute to the production of tailored SSHs for a specific application and with optimum properties. We collected data from the published literature covering the years 2014–2021, which was then fed into different ANN models where the input data (HTC temperature, process time, and the elemental content of hydrochars) were used to predict output parameters (higher heating value, (HHV) and solid yield (%)). The proposed ANN models were successful in accurately predicting both HHV and contents of C and H. While the model NN<sub>1</sub> (based on C, H, O content) exhibited HHV predicting performance with R<sup>2</sup> = 0.974, another model, NN<sub>2</sub>, was also able to predict HHV with R<sup>2</sup> = 0.936 using only C and H as input. Moreover, the inverse model of NN<sub>3</sub> (based on H, O content, and HHV) could predict C content with an R<sup>2</sup> of 0.939.
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spelling doaj.art-857d8d6fcea640488f8210716f08aebc2023-11-21T20:52:26ZengMDPI AGEnergies1996-10732021-05-011411300010.3390/en14113000Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage SludgeTheodoros N. Kapetanakis0Ioannis O. Vardiambasis1Christos D. Nikolopoulos2Antonios I. Konstantaras3Trinh Kieu Trang4Duy Anh Khuong5Toshiki Tsubota6Ramazan Keyikoglu7Alireza Khataee8Dimitrios Kalderis9Department of Electronic Engineering, Hellenic Mediterranean University, Chania, 73100 Crete, GreeceDepartment of Electronic Engineering, Hellenic Mediterranean University, Chania, 73100 Crete, GreeceDepartment of Electronic Engineering, Hellenic Mediterranean University, Chania, 73100 Crete, GreeceDepartment of Electronic Engineering, Hellenic Mediterranean University, Chania, 73100 Crete, GreeceApplied Chemistry Course, Department of Engineering, Kyushu Institute of Technology, Graduate School of Engineering, 1-1 Sensuicho, Tobata-ku, Kitakyushu 804-8550, JapanApplied Chemistry Course, Department of Engineering, Kyushu Institute of Technology, Graduate School of Engineering, 1-1 Sensuicho, Tobata-ku, Kitakyushu 804-8550, JapanDepartment of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology, 1-1 Sensuicho, Tobata-ku, Kitakyushu 804-8550, JapanDepartment of Environmental Engineering, Gebze Technical University, 41400 Gebze, TurkeyDepartment of Environmental Engineering, Gebze Technical University, 41400 Gebze, TurkeyDepartment of Electronic Engineering, Hellenic Mediterranean University, Chania, 73100 Crete, GreeceSewage sludge hydrochars (SSHs), which are produced by hydrothermal carbonization (HTC), offer a high calorific value to be applied as a biofuel. However, HTC is a complex processand the properties of the resulting product depend heavily on the process conditions and feedstock composition. In this work, we have applied artificial neural networks (ANNs) to contribute to the production of tailored SSHs for a specific application and with optimum properties. We collected data from the published literature covering the years 2014–2021, which was then fed into different ANN models where the input data (HTC temperature, process time, and the elemental content of hydrochars) were used to predict output parameters (higher heating value, (HHV) and solid yield (%)). The proposed ANN models were successful in accurately predicting both HHV and contents of C and H. While the model NN<sub>1</sub> (based on C, H, O content) exhibited HHV predicting performance with R<sup>2</sup> = 0.974, another model, NN<sub>2</sub>, was also able to predict HHV with R<sup>2</sup> = 0.936 using only C and H as input. Moreover, the inverse model of NN<sub>3</sub> (based on H, O content, and HHV) could predict C content with an R<sup>2</sup> of 0.939.https://www.mdpi.com/1996-1073/14/11/3000sewage sludgehydrothermal carbonizationhydrocharartificial neural networksmachine learningwaste management
spellingShingle Theodoros N. Kapetanakis
Ioannis O. Vardiambasis
Christos D. Nikolopoulos
Antonios I. Konstantaras
Trinh Kieu Trang
Duy Anh Khuong
Toshiki Tsubota
Ramazan Keyikoglu
Alireza Khataee
Dimitrios Kalderis
Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge
Energies
sewage sludge
hydrothermal carbonization
hydrochar
artificial neural networks
machine learning
waste management
title Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge
title_full Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge
title_fullStr Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge
title_full_unstemmed Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge
title_short Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge
title_sort towards engineered hydrochars application of artificial neural networks in the hydrothermal carbonization of sewage sludge
topic sewage sludge
hydrothermal carbonization
hydrochar
artificial neural networks
machine learning
waste management
url https://www.mdpi.com/1996-1073/14/11/3000
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