University of Oulu

Ämmälä, A. (2023). Comparison of Pin Mill and Hammer Mill in the Fine Grinding of Sphagnum Moss. Energies, 16(5), 2437.

Comparison of pin mill and hammer mill in the fine grinding of sphagnum moss

Saved in:
Author: Ämmälä, Ari1
Organizations: 1Fiber and Particle Engineering Research Unit, Oulu University, 90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.5 MB)
Persistent link:
Language: English
Published: Multidisciplinary Digital Publishing Institute, 2023
Publish Date: 2023-03-17


Dried sphagnum moss was ground using a pin mill and a hammer mill under various operating conditions, i.e., changes in the rotor frequency and feed rate. The specific energy consumption of the size reduction was recorded. The ground powder was characterized by median particle size, width of size distribution (span), loose and tapped bulk densities, and the Hausner ratio. Pin milling used less energy for size reduction than hammer milling, especially when the target size was below 100 μm. In both milling methods, the specific energy consumption was mainly caused by the rotor frequency used. However, in pin milling, the specific energy consumption was also dependent on the production rate: the higher the rate, the higher the energy consumption. No such dependence was observed with the hammer mill. The span was wider in pin milling than hammer milling in the intermediate product size range although the difference decreased at the fine and coarse ends. A similar pattern was found for bulk densities. However, the flowability of powder, as characterized by the Hausner ratio, was comparable between the grinding methods.

see all

Series: Energies
ISSN: 1996-1073
ISSN-E: 1996-1073
ISSN-L: 1996-1073
Volume: 16
Issue: 5
Article number: 2437
DOI: 10.3390/en16052437
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
Funding: Council of Oulu Region (grant A71069 aided by the European Regional Development Fund), Neova Oy (former Vapo), and Haarla Oy.
Copyright information: © 2023 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (