Extrusion technology plays a pivotal role in the manufacturing of feed for aquaculture. Traditional single screw (SX) and twin-screw (TX) technologies have been widely employed, each with their strengths and limitations. Motivation is to be able to produce feed at high technical quality to minimize feed footprint, yet being as close as possible to the least cost formulated feed, that meets all nutrient requirements.
It is the intent in this study to quantify the effect of recent innovations made to the design of twin screw extruders, focusing on quality, -effectiveness, and handling of oil and water addition. Newest twin screw technology (AF) use fundamentally different screw elements, built to be resilient to wear as well as being flexible towards raw materials and processing conditions. Latter implies operator skillset to be lesser of a factor as well as having the ability to operate with higher oil addition to the extruder itself.
Objective was to assess which extrusion system produces better quality feed at comparable density targets, is more cost-effective for utility consumption, and handles oil and water addition more effectively. Runs were done using a salmon feed formulation. 5 runs at different processing conditions was done on each of the three extrusion platforms. Mechanical and thermal energy input as well as water and oil additions were the variables used across the 5 different runs. For all runs, same density target was sought to be obtained.
Results indicate that the new twin screw technology outperforms traditional single screw and traditional twin-screw technologies in several key aspects. Specifically, it demonstrated:
These findings underscore the potential of the new twin screw technology, specific for aquaculture, to offer improved and more consistent feed quality while addressing key challenges in traditional extrusion systems – at wear cost comparable to single screw systems.