Modeling and analysis of pelletization process based on a multi-hole pelletizing device

Qinghai Jiang,Yu Sun,Kai Wu

doi:10.25165/j.ijabe.20191201.3264

Abstract

A multi-hole pelletizing device (MPD) was proposed to simulate the granular extrusion process of animal feed due to its cheap, fast, and controllable features. The compression mechanism was analyzed and discussed according to the compression force-time curve. This study applied response surface methodology (RSM) with a central composite design (CCD) to develop predictive models for the compression force Fout and the pellet properties which includes pellet density ρp, pellet moisture content Mcp, and pellet tensile strength Dp based on the MPD. The effects of feedstock moisture content Mcf (10%-18% w.b.), feedstock particle size Sf (8 meshes -24 meshes), die temperature Td (70°C-110°C) and compression speed Vc (5 mm/min to 25 mm/min) were investigated. Response surface models developed for the compression force and pellet properties have adequately described the pelleting process (R2 >0.95). The results showed the significant effects of all factors and most of the squared and interaction terms on the compression force and pellet physical properties. It can be concluded from the present study that moisture content and die temperature, followed by compression speed and feedstock particle size are the interacting process factors influencing compression force and pellet properties. Keywords: animal feed, pelletization, modeling, compression force, response surface methodology, analysis of variance DOI: 10.25165/j.ijabe.20191201.3264 Citation: Jiang Q H, Wu K, Sun Y. Modeling and analysis of pelletization process based on a multi-hole pelletizing device. Int J Agric & Biol Eng, 2019; 12(1): 17–23.

Highlights

Feed constitutes up to 60%-70% of the total cost for commercially reared broilers[1,2]
Based on the multi-hole pelletizing device (MPD) and response surface methodology (RSM), the present study investigated the influences of processing parameters on pellet properties and established predictive models for compression force and pellet properties, such as pellet density, pellet tensile strength (Dp), pellet moisture content (Mcp)
Higher compression forces and higher pellet density were observed at a lower moisture content of material (10% and 12%, w.b.) and lower-to-medium die temperature (80°C and 90°C)

Summary

Introduction

Feed constitutes up to 60%-70% of the total cost for commercially reared broilers[1,2]. It is important to study the effects of processing parameters on the feed pelletization process, so as to find the optimal conditions for the process, and achieve higher pellet quality and lower production costs. Previous research studies on feed pelletization have focused on the establishment of a cost-competitive process with high pellet quality and low energy consumption[1,8,9,10,11]. The pelletization process is complex, as the quality and energy consumption depend on the ingredient and mechanical properties of feedstock, the steam conditioning temperature, and the ring die size[12,13,14,15]. The chemical composition and physical properties of feedstock can vary greatly because of the differences in varieties, cultivation conditions and additives. The single pellet press method clarifies the compressibility of the pellet and allows for the evaluation of quality properties, such as density and tensile strength, in a simple and inexpensive manner

Methods

Results

Discussion

Conclusion