FEATURE
LOWERING OPERATION COSTS OF EXTRUSION:
I
A path to sustainable production of fish food by Farmet
n recent years significant effort has been given to sustainability in feed production. The path of lowering energy demands of the process and thereby the operation costs is one of the means of achieving sustainable feed production. Farmet a.s. has 25 years of experience in the field of technology of feed production via extrusion as well as oilseed pressing. The current demand for lower energy costs of the process inspires research and development of technologies that are less demanding of energy. To meet this challenge, Farmet is introducing an innovative way to recuperate energy for extrusion lines, coupled with an intelligent system for the control of process parameters.
Increasing efficiency by energy recuperation
For an evaluation of energetic demands of the processing of feed by extrusion, the following terms are commonly used: Specific Mechanical Energy (SME), i.e. energy supplied by the extruder’s engine, and Specific Thermal Energy (STE), i.e. energy supplied by heat transfer, most commonly by steam. The processes of extrusion and the following drying are very demanding energetically. The sum of SME and STE varies between 50 and 140 kWh/t and a nearly similar amount of energy is required for drying. During fish food production the feed mixture is heated up several times, when the feed is being shaped as well as when being dried. That is when energy loss by radiation and evaporation (after the extrudate has left the extruder; during drying) occurs. Our key innovation lies in a sophisticated system for energy recuperation that can save up to 30 percent of the overall energy consumption. Waste heat, generated by extrusion and drying, is used for a multi-step preheating of entering material before it reaches the extruder. For that purpose a special bin for the mixture is used,
where a system of heat exchangers preheats the material. This causes a decrease in SME and STE of extrusion. The control of the recuperation process is fully integrated into the extrusion line’s control system. It is the integration of the control of all the components that is key to ensure the stability of the process. The control system allows the operators to shorten the run-in required to achieve desired granule quality or to switch material type, which saves the resource material by decreasing the amount of insufficiently processed material.
Extrusion line management – advanced control of process parameters
Thanks to our long-term experience with automation of technology control and evaluation of process data for optimisation we offer a special tool for the control and optimisation of extrusion. Extrusion line management allows evaluation of process parameters and data from external sources, such as laboratory tests. The solution is always crafted according to the investor’s requirements; it is optimised for the particular technology in terms of operation costs, product quality, and serves as a resource for Farmet’s technical support. In feed production by extrusion, Farmet focuses on the optimisation of process parameters regarding both the quality of feed and a reduction in energy consumption. We have years of experience in this field thanks to collaboration with universities and research institutes and our own research and development. Combining our own know-how with the academic sphere is important for future success in this field. Effective technology and complex services comprise our company’s philosophy. We approach every client individually with the aim of providing the best possible solution regarding costs, product quality, and sustainability. www. farmet.eu
22 | September 2017 - International Aquafeed