Cimbria have just won an order for a new grain terminal at Uppsala north of Stockholm to Lantmännen Lantbruk, part of the Swedish cooperative Lantmännen.
The order includes a newly developed ECO-Logic continuous flow dryer, which is the latest generation of grain dryers with factors such as automatic operation control and process control as an essential part of the drying process. In addition, variable heat recovery of dry air and dust extraction are emphasized in the integrated tangentially acting dust separator type Dust Guards.
In their choice, Lantmännen has emphasized that the ECO-Logic dryer is not heated by fossil fuels such as oil and gas, instead direct electric heating has been chosen as something new in grain dryers of this size.
The heating method has many advantages, not least regulating, while at the same time ensuring a good and very even distribution of heat throughout the drying process. These advantages are significant in particular in connection with the size of the plant, which corresponds to a capacity of more than 100 TPH.
The fans for aspiration and recirculation are equipped with frequency converters, so that the power consumption of the large fans is controlled according to the exact requirements. The dryer is equipped with automatic control of the recirculation zone, which is controlled gradually depending on the product, as well as the temperature and humidity of the grain and dry air.
The plant is scheduled to be ready for commissioning at the end of 2018.
Construction and technical features: Intelligent drying with optimum energy consumption
The ECO-Logic dryer was introduced to Cimbria’s customers at the recently held Agritechnica exhibition, with the ECO-Logic as one of the main exhibits for Cimbria. During the exhibition many approving remarks from customers was given to the new design and the ways the customer requirements are incorporated in the new design.
For customers, gentle and uniform drying with optimum energy consumption are essential, in addition to a high level of automation and remote control, low dust emission and low noise levels. These requirements are augmented by demands for high reliability and availability, as the dryer has to operate without interruption during the harvest and drying season. A continuous flow dryer consists in principle of three sections: The heating section, the dryer column and the exhaust section. In the heating section the ambient air is heated and mixed with the recirculated air and is led into the drying column via hot air ducts. In the drying column the heat of the drying air evaporates the moisture in the grain, whilst at the exhaust section the drying air is expelled through the exhaust fan and the dust separation devices.
Gentle and uniform drying
The main objective in the heating section is to obtain a completely uniform temperature at the dryer column inlet. For the ECO-Logic™ dryer a hot air mixer was designed by utilising Computational Fluid Dynamics (CFD) analysis and this air mixer ensures a maximum +/- 5° C tolerance of the drying air to guarantee even, accurate and gentle drying of the grain.
The discharge device of the dryer column ensures an even discharge of the grain across the entire outlet area of the dryer. The discharge principle is based on Cimbria’s well-known volumetric discharge system, which provides a very accurate indication of capacity, since each discharge has a certain fixed volume. With the continuous discharge system of the new ECO-Logic™, the kernels are present in hot or cold air for a very limited amount of time. High grain quality is maintained, thus assuring germination ability and grain quality.
The ECO-Logic™ grain mixing device has been designed to redirect the hottest grain so that it changes place with the colder and wetter grain at the colder part of the dryer in order to ensure even drying of the grain.
Energy efficient solution
A prerequisite for achieving high dryer efficiency is to ensure that the exhaust air humidity level is as high as possible and the volume flow of the exhaust air is as low as possible. With the very even temperature distribution and accurate control of the dryer, the drying temperature can be increased and kept at a high level without damaging the grain, thus ensuring high humidity in the exhaust air and hence high efficiency. To reduce the volume flow of exhaust air and to utilise the fact that the exhaust air at the lowest drying sections is not fully saturated and is relatively warm, the number of recirculation sections has been optimised and is controlled by a sliding valve.
In general, the new dryer is approximately 20 % more efficient than a traditional dryer such as the A-dryer and 10 % more efficient than a dryer like the ECO-Master.
Low dust and noise
The ECO-Logic™ is provided with fans of the centrifugal fan type with limited noise emission. For control of dust emission, a dust
guard is designed to capture the dust particles, thus ensuring that the ECO-Logic™ dryer complies with environmental regulations.
An overall vision for the ECO-Logic™ dryer was to implement a control system incorporating Cimbria’s process knowledge in grain drying. With the newly developed control system, users are provided with an automatically controlled drying process, where changes in operational parameters are made to comply with changes in drying conditions – e.g. higher moisture content of the incoming grain – by means of feed forward control of the dryer. This means that users will be able to operate the dryer virtually unattended.
The structural design of the dryer complies with Eurocodes, and manufacture of the structural steel is carried out according to EN1090. This ensures straightforward approval from local authorities.
Range of products
ECO-Logic™ is manufactured in standard capacities covering drying requirements from 20 to 250 t/h wheat based on a moisture reduction of 19-15% and is capable of drying all major cereals. Larger capacities are available upon request.