- Title
- Modelling and optimisation of a multiple hearth furnace for the generation of advanced material
- Creator
- Clark-Welling, Samantha
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2024
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Multiple hearth furnaces (MHF) have played a crucial role in industrial applications for over a century, showcasing versatility in roles such as calcination, ore-roasting, and activated carbon regeneration. Despite their extensive use, research on these vessels has been limited, resulting in a scarcity of knowledge regarding their inner workings. This can be attributed to the complex nature of the plant vessel, and its high temperatures and extremely volatile conditions inside the hearth. It has been challenging to characterise what is happening within the hearth in terms of heat transfer, kinetics and residence time. This PhD project's aim was to illuminate these issues and work on the characterisation and optimisation of the process as an all-encompassing and adaptable model in Aspen Plus®. The model in this thesis will be based on the sugar industry, in particular the regeneration of granular activated carbon that have adsorbed sugar colourants within its porous structure. The thesis represents a culmination of interdisciplinary efforts, combining chemistry, mechanical engineering, and chemical engineering. With key findings emerging from a each aspect. This project was fortunate to base this off the real-world industry multiple hearth furnace in Racecourse, Qld, Australia with the collaboration of furnace operator, Wilmar International, and furnace manufacturer, J ord International. The initial chemistry experiments involved the characterisation of the particles, including the kinetic and thermal degradation of the industrially sourced GAC and the material in the absorbed species. As well as a study of the pyrolysis stage in which these particles undergo remove of material from within. The key findings from the investigating the chemistry of the material at hand, it was found that the GAC through the MHF has been inefficient in its regeneration. Subsequently, the next aspect of the thesis was focused on it's physical characteristics including the rolling and sliding resistance these particles have, in order to simulate their movement from within the hearth to obtain the residence time on each hearth. Finally with these all successfully completed, the simulation modelling of the multiple hearth furnace could be completed within the process flow environment of Rocky DEM software. The results from this aspect was that the residence time compared well with other literature findings, and were found to be 17, 18, 45, 25, 57, and 1 minute(s) per hearth, respectively. Another piece of the puzzle was to determine the kinetics of the pyrolysis phase, through the use of the results of the TGA-DTG-DTA experiment, as well as the residence time of the hearths. Insight into the reactions of similar materials and models gave confidence that reactions would convert to the full thermodynamic extent of the reactions due to the heating rate experienced and the residence time on each hearth, as calculated by the detailed DEM modelling conducted. Finally, the simulation of the multiple hearth furnace could be constructed, utilising the results of each of the other experiments presented here. The simulation was modelled in Aspen Plus ® software, and was broken into the three stages (drying, pyrolysis, and gasification) present, and the representation of the hearth(s). Each of these stages were comprised of a Gibbs Free Energy reactor and a separator. The model was used to compare the different operating conditions (StOC, HOC and SOC) as well as provide information on the energy savings that the reduction of steam would have on the system. The results from the simulations showed that the reduction of steam had positive effects on the system, including less carbon in the exhaust gas, more decomposition of the colourants within the drying and pyrolysis stages and the water and energy savings from not operating with such high mass flow rates of steam. In summary, this thesis not only contributes to the understanding of multiple hearth furnace operations but also provides a valuable framework for optimising the regeneration of GAC in sugar industry applications. Even though this research did not reach the goal of an adaptable model, it sets the stage for future advancements in multiple hearth furnace modeling, offering a comprehensive foundation for further exploration and refinement of these complex industrial processes.
- Subject
- multiple hearth furnace; sugar; colourant; pyrolysis; modelling; DEM; rocky; Aspen Plus; simulation
- Identifier
- http://hdl.handle.net/1959.13/1510011
- Identifier
- uon:56336
- Rights
- Copyright 2024 Samantha Clark-Welling
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 138 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 10 MB | Adobe Acrobat PDF | View Details Download |