Maize seed production is a growing market in some African countries. But seed production requires special technologies which ensure the quality of the produced seed, thus warranting investments and guarantying return on investments. For seed maize, corn cob dryer houses are essential. In order to prevent seed damage on the field and later on during processing, seeds have to be harvested earlier or wetter (30 – 40% MOI) than commodities (13 – 15% MOI), making cob drying necessary. It is of paramount importance, that stress cracks are avoided, energy is saved and the drying processed is optimized in terms of capacity and workload. Sun dried seeds cannot be managed accurately on the point and often lack in germination ability. The susceptibility for breakage due to stress cracks and tiny fissures shows a linear correlation with temperature, and the proportion of cracked/popped kernels often reach more than 50%. Only in corn cob dryer houses, specific drying for individual genotypes can be controlled in terms of time, tempering phases, air temperature, relative humidity, air flow rate and air distribution.
PETKUS Corn Cob Dryer Houses have proven their versatility and drying quality in many different environments from South-East Asia to Europe and Russia. Since decades, the company and its highly qualified engineers have planned, designed, built, delivered, installed and commissioned single as well as double pass dryer houses. The entire product and service range, from design engineering to construction and consulting is done strictly in-house and within the PETKUS Group members to make sure, that clients only deal with experienced professionals.
PETKUS Corn Cob Dryer Houses consists of several independent drying chambers based on capacity demands and customer’s requirements. The chambers walls consist of trapezoidal steel profile walls and are equipped with filling hatches, emptying flaps and air flaps as well as fans and burners with combustion chambers. The material to be dried is softly fed into the drying chamber via the filling hatches. The material is dried on an inclined and perforated steel plate (ventilation floor) through which the air enters and exits.
The drying process with upper or lower air ventilation is well controlled via the ventilation door and the supply air flaps. The installed limit switches are connected to the plant control system. The alternating drying process with top and bottom air results in an even drying of the entire filling layer. This guarantees optimum drying results while at the same time treating the material in a gentle way. The drying process is monitored by temperature measurement with several sensors above and below the material in the drying chambers. The sensors are connected to the plant control system. After the drying process has been completed, the material falls through the discharge flap onto the emptying conveyor and is transported away for further processing.
PETKUS offers a wide range of dryer house capacities for both systems, the single as well as the double-pass reverse. Due to its special design, the PETKUS dryer houses are lightweight and easier/faster to build and install on site. In addition, they fulfil very high EH&S criteria as cob filling hatches are separated from air outlet hatches and therefore, the operating personnel on the dryer house filling level is not at all exposed to contaminated air.
Access and costs of fuel for the burner can be crucial for some areas. Hence, PETKUS Corn Cob Dryer Houses can be operated with gas, oil, diesel, petrol, LPG or bio fuels, e.g. from wood chips, rice or maize straw and husks, corn cobs or palm husks. PETKUS installed in Asia dryer houses with corn cob burner with hot water heat exchanger as well as air heat pumps with dehumidifier pumps. Latter showed considerably reduced drying costs of app. 3 cent per kilogram.