The maize harvest generally takes place in September, when the humidity values are around 24-25%. These values, however, vary according to the climatic conditions and the ripening stage of the product. In some areas, maize is harvested even at 40-45% humidity and it needs to be brought to levels suitable for storage as soon as possible.
If the grain is not subjected to a drying process as soon as it reaches physiological maturity, in fact, the passage of time would lead to inevitable degenerative developments, since maize is a product of natural origin.
For optimal drying, it is necessary to use a special system: a maize dryer machine. In this article, we are going to discover 4 features to consider in order to evaluate their quality and efficiency.
How does the maize drying process work?
The drying of maize generally takes place by ventilating the grain with a high mass of hot air which is subsequently expelled, once relative humidity values close to saturation have been reached. The goal is to reduce the moisture content of the maize to a level of 14%, by exporting part of the water contained in the grains.
Maize is a very robust type of grain that accepts being dried with high air temperatures (even 120 °C), in order to remove 4-5% of humidity per hour of drying. At these temperatures, the grain is sterilized and therefore no longer germinates. If it is necessary to dry maize by sowing, the treatment temperatures will be lower and the drying times will be extended.
Now let's see what are the four main attributes that distinguish a quality maize dryer machine.
#1. Drying time
The drying time depends on the evaporation capacity of the machine and the initial moisture level of the incoming raw material. The evaporation of the water is not uniform, but rapid at high humidity levels and progressively slower near the storage limits.
The drying duration also depends on the external climatic conditions, so much so that in situations of extreme temperatures (very hot or very cold) it can be halved, while reducing fuel consumption.
Thanks to their innovative technology, Mecmar mobile grain dryers are designed to allow savings of up to 10% in the use of fuel. In the case of maize, Mecmar grain dryers can remove up to 5% of moisture in just one hour.
#2. Hot air temperature
The maximum level of temperature inside the dryer machine, in addition to the type of system, basically depends on two factors:
- the initial moisture level of the grain
- the destination of the product
The temperature tolerable by the cereal decreases as its moisture content increases, as too rapid evaporation of the water could cause negative repercussions on the maize and therefore on its subsequent processing.
Furthermore, it is essential to maintain a balanced situation: if the air temperature is very high, on the one hand the productivity of the machine will increase, but on the other hand it will risk to burn the grain. Therefore, a temperature control system must always be included in the design of a maize dryer machine: Mecmar mobile dryers offer both manual and automatic control solutions.
The air temperature in Mecmar plants during corn drying is usually 110 °C, variable depending on the moisture, the final use of the product and the external environmental conditions.
#3. Air flow in the system
Another parameter of great importance is the air flow inside the machine, which must be optimized based on the humidity level of the cereal and the counter pressure generated by it.
Mecmar tower dryers are equipped with a particular operating structure and a ventilation system that is easy to inspect and strengthened where necessary. Thanks to the movement of the grain and the channeling of the air flow, homogeneous drying is guaranteed for the entire batch inside the dryer. In addition, Mecmar also offers innovative grain roasters which, through automated technology, allow to intervene to improve the efficiency of the drying process, so that the flow of hot air roasts the grain homogeneously.
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#4. Continuous mixing of the product for maximum drying homogeneity
The cereal drying cycle takes place in four phases: filling the machine, drying, cooling and unloading the product.
The principle of operation of the grain dryer is that heated air flows pass through the product layer. Through a precise choice of the operating mode of the system, it is possible to create the right conditions to ensure a continuous and uniform movement of the product along the entire height of the drying cylinder. All the wheat grains receive air in all directions in order to contribute to the homogeneity of drying at the end of the process.
This is the best performing corn drying process, able to minimize crop losses and improve the quality characteristics of the final product.
A quality maize dryer machine allows you to dry in an optimal and homogeneous way, even in extreme working conditions (temperatures below zero, initial humidity even at 45%, etc.) and very quickly. The flow rate and temperature of the air inside the system affect the drying time necessary to allow the desired level of humidity to be obtained, homogeneously over the entire mass to be dried. Through a continuous recirculation of the product inside the dryer, it is possible to reach an ideal moisture level for subsequent processing, evenly distributed.
Thanks to its decades of experience and continuous improvements integrated from year to year based on feedback from the field, Mecmar is able to offer the best drying and roasting systems: its winning solutions combine the robustness of the systems with elements of reliability and safety in the drying phase.
If you want to learn more about Mecmar maize dryer machines, do not hesitate to contact us: our team of experts will be ready to answer any kind of doubt and question.