How dryer airflow automation can increase energy efficiency

In the production of extruded feed, hot air drying accounts for almost 50 % of the total energy consumption. Naturally, our customers in the industry have incentive to improve fossil fuel efficiency to convert gas savings directly to bottom line earnings and a reduction of carbon footprint.

However, opportunities to reduce gas consumption in the dryers are often overlooked due to anxiety of compromising process- and product integrity. Many modern pet food facilities have dampers, valves, etc. that are locked in fixed positions, arising from an initial equipment run-in phase. If gas savings are to be realized across all products and production lines, active- and online adjustments of process airflow is needed. This is to react towards shifting production conditions and -volume flow as well as product size, composition and recipe.

GRAINTEC’s new dryer airflow automation makes use of information retrieved from sensors placed in air ducts, to judiciously adjust air flow control measures to appropriate positions. This allows dryers to react on relevant processing conditions. “Recent studies have demonstrated that by implementing dryer airflow automation in extruded pet food production, annual gas savings of 3 – 10 % can be realized, depending on processing conditions”, says Anders Haubjerg, Sr. Process Engineer in the Business and Technology Development at Graintec A/S. And he continues; “That is often around a year in payback time, so we do encourage our customers to contact us to hear more – this is a real opportunity to pick the low hanging fruits”.

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The leaflet includes information about:

  • Cross contamination
  • Clean zones
  • Construction details
  • Salmonella

The sanitary design of production facilities is important in order to ensure safety. Especially in pet food production, demands are high with regard to strict hygiene regulations and food processing standards. Hygienic design of machinery and a factory layout that enhances good hygiene are therefore crucial in order to ensure food safety.

It is not possible to avoid contaminated raw materials from entering the raw material zone of the producing factory, but it is possible to prevent it from spreading. Moreover, it is important to keep the plant clean and dry. It is practically impossible to alter badly designed plant layouts, machine supports and process equipment at a later stage and therefore it must be taken care of in the design phase of any project. A hygienically designed plant will reduce maintenance and cleaning costs.

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At Graintec we have many years of experience within the field and we have the knowhow about how equipment, facilities and production plants for the feed production industry must be designed in order to protect animal foods from disease-causing bacteria, chemicals and other contaminants.

GRAINTEC can be of assistance when the potential hazards at production facilities are examined and we can assess the required feed safety plans to ensure that production is according with FDA food safety regulations. 

Our local office in Kansas City is ready to assist you with their expertise in hygienic design solutions for your production facility:

Graintec, Inc.
One Main Plaza
4435 Main Street, Suite 504
Kansas City, MO 64111
United States
Phone:   (+1) 816-621-3000

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“Knowledge Winter Camp” at Graintec Headquarters

Week 7 is winter vacation time in the Nordic Region, most of the schools are closed and a lot of people are enjoying their winter vacation.

For us at Graintec the slower pace amongst our customers gives us the opportunity to host our own internal Graintec “Knowledge Winter Camp”. This winter camp has got little to do with skiing and everything to do with the industry of fish feed and pet food production, where the pace of innovation and process development never slows down.

Graintec_seminarSo this week’s internal Graintec “vacation” equals presentations and lectures on new standards and methods of best practices involved in our processes of: Design / Execute / Install / Maintain – all to improve and share our knowledge bank.

Optimization is key internally and externally, and something our business partners always can benefit from – we also arrange on site demonstrations and education programs in respect to usage and maintenance of equipment and production lines.

Or we can organize customized business seminars at our head office in Vejle.

Contact us in order to discuss how we can assist your organization.


The challenge of technical quality prediction

Figure 1b. Interior of extruded fish feed pellet

Interior of extruded fish feed pellet.

It is important to produce extruded fish feed at a consistent, high technical quality level. But sometimes it does happen that the technical quality become poor, and it is a difficult task to identify why and, more importantly, how one might avoid this in future productions.

 In the next issue of Journal of Food Process Engineering Graintec will publish their latest findings on the identification of structural properties of extruded fish feed and their influence on technical product quality. Only with knowledge of the most favorable structural behavior of the product one will be able to optimize and consistently predict the technical quality, e.g. under influence by the chosen parameters in the drying process.

Follow the news at for notification on publication, which is expected to be sometime soon.

Sea lice are a challenge to farmed and wild fish

Challenges comes in different sizes and shapes. One the small-sized challenges in the sea is the common sea louse, known as the Salmon louse. It is small marine parasites that occur naturally on wild fish. It is planktonic and transported on the tide, attaching itself on the skin of the fish.

To face the challenge

A non-medicinal possibility are a high standard on clean net and cages with fine mask nettings among others.

Another possibility is pharmaceutical products. GRAINTEC have designed and built several production plants for the production of medicated or functional feeds used to reduce the problem from sea lice in salmon.

To design and execute projects for functional and medicated feeds requires high expertise and knowhow in hygiene feed/food plant design, and the process technology used should be very accurate and safe in terms of additions of various ingredients together will full traceability. The process line should have wash-down capability from the point where medicine is added.


Progress in the ongoing innovation projects at Graintec

Ongoing innovation project at Graintec: improving pellet quality and energy efficiency in Salmon/Trout feed drying installations

Energy-recovery-light-flow2We currently have two major projects located in our Business and Technology Development department. One of these is an Industrial PhD Project, which is run by Anders Haubjerg. The project is conducted in collaboration with the University of Southern Denmark.

The project aims to improve energy efficiency in dryers and shall help GRAINTEC to optimize the design of especially salmon/trout feed drying installations with regard to energy efficiency and product quality. The improved design will be available for GRAINTEC’s customers to predict specific energy consumption and final technical quality of produced fish feed pellets, as a response to the conditions used in the drying process. Thus, the key objective in the project is to relate specific energy consumption and expected technical quality to drying parameters; air temperature, retention time, bed depth, moisture content of product, air humidity and zone-wise variations of the aforementioned.

A large part of the project will rely on mathematical models of the drying process to predict the energy consumption. However, models are only as good as their actual ability to predict reality. Therefore we have established collaboration with Wenger in the demonstration of the model behavior on a new Laboratory Scale dryer. The dryer has been custom built by Wenger to suit the demands for validating the new drying model.Fishfeed

The potential of obtaining a multi physical description of parameters in the drying process which give rise to the formation of structural properties in low starch-based, porous pellets constitutes the research value in this project. In the project we have so far established knowledge of the structural mechanics in fish feed pellets, which promote mechanical durability. It was found that particular viscoelastic properties of a pellet give good mechanical durability, when measured in the DORIS tester.



From the project we hope to obtain better knowledge on how to obtain a reproducible, high pellet quality without compromising energy-efficiency. The last few weeks, Anders has been focusing on optimizing the performance and operation of the Lab Dryer:


“I have connected power and steam and installed a fan in the power cabinet, various safeguards anti-vibration utility, and isolation around ductwork. I am now working on calibration and validation of sensor readings for air humidity and we also need to rewrite some signals in the software.”

The project, which was initiated in September 2012 is scheduled to be finalized in April 2016.




Pictures: Graintec / Aktuel Naturvidenskab