Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • apa.csl
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Investigation of how the pelletizing process is affected by different process parameters in a single pellet press: The effect of different parameters on the energy use in pellet production and the quality of pellets
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
2023 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Undersökning av hur pelletiserings processen påverkas av olika processparametrar i singel pellet press. (Swedish)
Abstract [en]

Biomass as a renewable energy source has increased for many years, it plays a big role in meeting heat and power needs. This increase replaced fossil fuel, contributing to global environmental problems, including global warming. A new environmentally friendly way needed to be developed to solve the problem and meet the needs while keeping the cost and environmental impacts down. Biomass pelletization is a solution to the problem, it converts the material into uniformly sized pellets that are both mechanically and biologically.The full-scale tests are a way to develop pellet production, yet only a few publications have been published on a full-scale pellet plant. The reason is the high costs and the unpractical process since the production has to be stopped to perform the tests. Therefore Single pellet press (SPP) is considered to be a more convenient way to understand the pelletization process. This paper presents experimental research studying the influence of different pelleting parameters on quality and energy use, using a single pellet press (SPP) and continuous single pellet press (CSPP). Five parameters were varied to investigate how process parameters affect the pelleting process: moisture content, press speed, temperature, hold time, and press length. The influence of the process parameters was conducted using spruce and birch as raw materials.The single pellet press is used to convert various raw materials into compressed pellets. It consists of a steel die with a channel hole with a conical entrance and a removable bottom plate at the bottom. The die has a heating element, and the press unit has a piston to press the material. The heating element is to control the temperature and the piston velocity can be controlled. The continuous single pellet press is similar to single pellet press but with no hold time, which is replaced with different press lengths. Three different press lengths were examined 16, 20, and 25 mm. It was noticed that the moisture content has the most impact on the energy used to produce pellets, the quality of pellets, and on all the process parameters. Rising the press speed decreases the energy used, with no effects on quality. The energy used decreases when rising the pelleting temperature, and the density, durability, and hardness increase. The hold time has a minimum effect on the pelleting process and the quality of pellets. Press length showed different results from other studies, a press length of 25 mm requires less energy than a press length of 16 mm. It was also noticed that pelleting with high temperature should avoid low press speeds due to an understandable behavior. More energy is used at 80 ℃ compared to a higher temperature for both materials and moisture, that increasing temperature enhances the flexibility and adhesion between particles, decreasing inter-particle gaps. This process creates a strong bond among the material particles and improves the connection between materials. By reducing the particle spacing, van der Waals and electrostatic forces become active, promoting cohesive interactions among the particles and improving the compression energy of the produced pellets. Heating also plays a big role in softening the lignocellulosic materials, which improves the binding between the feed and enhances pellet durability. However overheating causes excessive softening of lignocellulosic materials, decreasing pellets’ durability due to insufficient binding. The durability of hardwood was below the acceptable level, and therefore it needs to be investigated more. Overall, when using single pellet press (SPP), only moisture content needsto be considered. Higher temperature and higher press speed are recommended when using continuous single pellet press (CSPP). 

Place, publisher, year, edition, pages
2023.
Identifiers
URN: urn:nbn:se:kau:diva-98412OAI: oai:DiVA.org:kau-98412DiVA, id: diva2:1836169
Educational program
Engineering: Energy and Environmental Engineering (300 ECTS credits)
Supervisors
Examiners
Available from: 2024-02-12 Created: 2024-02-08 Last updated: 2024-02-12Bibliographically approved

Open Access in DiVA

No full text in DiVA

By organisation
Department of Engineering and Chemical Sciences (from 2013)

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 28 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • apa.csl
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf