What is preconditioning and its benefits? This article, the first in a 2 part, explains.
Preconditioning is a unit operation that has long been associated with extrusion processing (and with other feed processing methods such as pellet milling). Although a seemingly simple process, there are many design variants available. There are also a number of operational parameters that need to be given careful consideration when selecting and/or designing a process application. The following seeks to present some of the key design and process control criteria, such that process optimisation may be completed in a less empirical manner.
Preconditioning, as applied to feed manufacture, involves adding moisture and heat to the feed formulation before extrusion (or pelletising). This involves adding water, normally partially as liquid water, and partially as steam, while mixing (and holding the mix). So the primary objectives of the preconditioning in extrusion of feeds are to:
Note that in this discussion, cooking is used as a generic term to describe the various material transformations occur within the product as it passes through the system. These simple relationships highlight the key variables in preconditioning. The different manufacturers of preconditioning equipment each have their own approaches to how to control and optimise the key variables. In this article we will discuss key attributes of preconditioning for extrusion of aquafeeds.
All of the preconditioner equipment suppliers regularly espouse the benefits of this technology. A number of the benefits typically claimed are presented in the interactive image below. If we examine these benefits, we can see that they all relate to those basic functions of preconditioning:
Potential benefits of preconditioning – click and find out more..
In the second part of the series we will delve into the key parameters of preconditioning and the different types of preconditioners. The authors are presenting short courses on “Aquafeed Extrusion Technology” and “Drying Technology” at Centre for Feed Technology, FôrTek, Norway, in May 2016, plus an Extrusion Course in Thailand in July 2016 (www.fie.com.au/events)
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