Agricultural and Biosystems Engineering Publications

Campus Units

Agricultural and Biosystems Engineering, Civil, Construction and Environmental Engineering, Food Science and Human Nutrition, Toxicology

Document Type

Article

Publication Version

Published Version

Publication Date

2019

Journal or Book Title

Energies

Volume

12

Issue

3

First Page

565

Research Focus Area(s)

Biological and Process Engineering and Technology

DOI

10.3390/en12030565

Abstract

We propose a ‘Waste to Carbon’ thermal transformation of sewage sludge (SS) via torrefaction to a valuable product (fuel) with a high content of carbon. One important, technological aspect to develop this concept is the determination of activation energy needed for torrefaction. Thus, this research aimed to evaluate the kinetics of SS torrefaction and determine the effects of process temperature on fuel properties of torrefied products (biochars). Torrefaction was performed using high ash content SS at six (200~300 °C) temperatures and 60 min residence (process) time. Mass loss during torrefaction ranged from 10~20%. The resulting activation energy for SS torrefaction was ~12.007 kJ·mol−1. Initial (unprocessed) SS higher heating value (HHV) was 13.5 MJ·kg−1. However, the increase of torrefaction temperature decreased HHV from 13.4 to 3.8 MJ·kg−1. Elemental analysis showed a significant decrease of the H/C ratio that occurred during torrefaction, while the O/C ratio fluctuated with much smaller differences. Although the activation energy was significantly lower compared with lignocellulosic materials, low-temperature SS torrefaction technology could be explored for further SS stabilization and utilization (e.g., dewatering and hygienization).

Comments

This article is published as Pulka, Jakub; Manczarski, Piotr; Koziel, Jacek A.; Białowiec, Andrzej. "Torrefaction of Sewage Sludge: Kinetics and Fuel Properties of Biochars." Energies 12, no. 3 (2019): 565. DOI: 10.3390/en12030565. Posted with permission.

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Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Copyright Owner

The Authors

Language

en

File Format

application/pdf

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