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).
Access
Open
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Copyright Owner
The Authors
Copyright Date
2019
Language
en
File Format
application/pdf
Recommended Citation
Pulka, Jakub; Manczarski, Piotr; Koziel, Jacek A.; and Białowiec, Andrzej, "Torrefaction of Sewage Sludge: Kinetics and Fuel Properties of Biochars" (2019). Agricultural and Biosystems Engineering Publications. 1001.
https://lib.dr.iastate.edu/abe_eng_pubs/1001
Included in
Bioresource and Agricultural Engineering Commons, Oil, Gas, and Energy Commons, Sustainability Commons
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.