Within in the next five years, the annual production of aqua feed is expected to make a considerable increase from todays 50 million tonnes to no less than 70 million tonnes per year in 2020. The industry is experiencing a rapid growth in order to meet the rising demand for marine protein. However, a significant growth in production unavoidably triggers a significant growth in energy consumption. This consequence can prove to become rather costly in a world where taxations implemented to prevent environmentally damaging CO2 emissions are increasing. In this regard, the consequence of a heightened energy consumption will also become costly for the environment. Can we really afford that? Therefore, a critical inspection into the production lines’ largest energy guzzlers is recommendable.
One of the most important procedures during the production of extruded aqua feed is the drying of the pellets. This process will determine the technical quality of the product; its shelf life (especially in connection to transportation), its ability to absorb large amounts of fat/oil, prevent pellet corruption and ensure its ability to either flow or sink when fed to the fish. All in all to ensure the lowest loss of profit. The drying process can at the same time be put down for at least 60 % of the total energy consumption per tonne produced aqua feed, which in 2020 will reach an annual energy consumption of no less than 7,8 billion kWh – corresponding to the electricity use of approximately 781,000 single-family homes per year.
The drying is a delicate process in the production, but with the right adjustments, the challenge can be turned into a competitive resource. Of course, it is easier said than done. In order to ensure a tolerable homogeneity during the drying process most manufactures resort to multiple conveyor belts or multiple vertical batch dryers with multiple drying-zones, retention-time, air volume, air temperature, fluctuating humidity levels and others variables, which with absolute certainty can make the consequences of even the slightest adjustment to any of the parameters utterly immeasurable.
In fear of creating incalculable consequences harming the quality of the product, the only variable adjusted is often the temperature of the airflow. Warm air is normally the main component in the drying process, and there seems to be a belief that by adding warmth the quality increases. Unfortunately, the only thing that will happen by adjusting the temperature up and down is the risk of tampering with the pellet’s quality; all the while, the energy consumption may experience a significant increase.
According to the Potsdam Institute for Climate Impact, we should make an effort to our environment, as their studies show that the heat level may increase with 4 ⁰C before 2021, which will cause a linkage of harmful consequences. For instant severe water-shortage on global scale and the sea will rise up to 1 meter, causing tremendous damage. Damage that the IPCC (Intergovernmental Panel on Climate Change) report of 2014 clearly states we are not ready to handle. This are surely alarming prospects, however the report fortunately also brings some consolation. “…there is a growing recognition that affordable, scalable solutions are available now”. A consolation we believe we should understand as a challenge.
The pressing question of how to make quality, economy and environmental friendliness go hand-in-hand must now certainly be of interest to many feed producers. In collaboration with The University of Southern Denmark, Graintec A/S has initiated a Ph.D. project, which has the objective to clarify the correlations between the many parameters involved in the drying process in order to make an eco-friendly solution. Furthermore, it is sought to construct a mathematical model, making it possible to outline and predict the active water content and temperature in the pellets while drying, through systematic testing. The first test results show that airspeed has a great impact on creating a uniform drying process of the pellets – without turning up the heat.
The project is expected to end in spring 2016 and results will be published.
Environment, quality and economy in profitable interaction is what we research to obtain.