Densification process modeling and commonly used systems

Authors: Tumuluru, Jaya Shankar

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 11/18/2022
Publication Date: 6/29/2023
Citation: Tumuluru, J. 2023. Densification process modeling and commonly used systems. In: Tumuluru, J.S. editor. Densification Impact on Raw, Chemically and Thermally Pretreated Biomass. First Edition. Singapore: World Scientific Publishing Co. Pte. Ltd. p. 15-48. https://doi.org/10.1142/9781800613799_0002.
DOI: https://doi.org/10.1142/9781800613799_0002

Interpretive Summary: The compaction behavior of biomass particles depends on the chemical composition of the biomass and process conditions such as temperature, pressure, and residence time. There are various models such as the Spencer and Heckel model, the Walker model, the Jones model, the Cooper-Eaton model, the Kawakita-Ludde model, the Sonnergaard model, and the Panelli-Filho model, and the Asymptotic modulus, which are commonly used for understanding the compression characteristics and relate it to the density of compact produced. Different densification systems such as pellet mill, briquette press, and screw extruder are developed based on the compaction behavior of the particles. These systems help convert raw and loose biomass into a compact with higher density and definite size and shape. These compacts have better feeding, handling, storage, and transportation characteristics. This chapter discusses the compaction models and densification systems that are commonly used for biomass densification.

Technical Abstract: Various fundamental models were developed to understand the compaction characteristics of powders. Many authors have used these models to understand the compaction behavior of biomass particles. Biomass’s compression, relaxation, and frictional (adhesion) properties depend on compressive force, moisture content, and particle size and shape. The various models commonly used for biomass are the Spencer and Heckel model, the Walker model, the Jones model, the Cooper–Eaton model, the Kawakita–Lüdde model, the Sonnergaard model, the Panelli–Filho model, and the asymptotic modulus model. Various researchers tested all these models for different biomass grinds. For example, the Cooper– Eaton model parameters for biomass grinds can help understand prominent compaction mechanisms, such as particle rearrangement and elastic and plastic deformation. However, the mechanism of mechanical interlocking and the ingredient melting phenomenon during biomass compression are also important to understanding the compaction mechanism. The Kawakita–Lüdde model helps relate the biomass grinds’ initial porosity and the compacts’ yield strength. Numerical software, such as Pro/Engineer, PFC3D, and others, are gaining importance in understanding biomass grinds’ compaction behavior during the densification process. The common systems used for biomass densification are pellet mill, briquette press, and screw extruder. Among the densified products, the pellets produced using a pellet mill are widely used worldwide for biopower production.