Mobile Processing Units
DADTCO’s mobile processing units exists of three parts; the first part is called the AMPU (Autonomous Mobile Processing Unit), the second part is the MRU (Mobile Refinery Unit) and the third part is the dryer, either central or mobile. In this section the AMPU and MRU are described.
The AMPU processes fresh cassava roots (< 24 hours after harvesting) into cassava cake that in its turn is refined in a Mobile Refinery Unit (MRU) to produce cassava starch cake. Cassava starch cake is an intermediate product of dough-like consistency that has a proven shelf life, under normal ambient conditions, of over six months. The cake is highly compact and therefore easily transportable by truck to a central location.
The instantaneous throughput through the AMPU is 4-5 MT cassava roots per hour, but the annual capacity depends on daily operating hours and shift configurations. At maximum, one AMPU can process up to 100 MT of roots per day (on the basis of 5 MT per hour of roots on 3 x 8 hour shifts totaling 20 hours per day net production time on 300 working days per year). This assumes that the quantity of roots harvested during the day is sufficient to feed the unit during the hours of darkness. This translates into an annual roots processing capacity of 30,000 MT, in turn producing close on 15,000 MT pa of cassava starch cake.
The whole mobile process is centered on the core machinery, the high speed rasper in the AMPU. This rasper is the smallest size technically possible machine while still being capable of releasing 98% of the starch granules in the cassava roots. The starch granules are situated inside the cells. The rasper mechanically rips open the cell walls to release the starch. The lower the percentage of released starch, the higher the starch losses and subsequently financial losses. Food Grade Processing of cassava must obligatory have a high speed rasper if not the food industry will refuse the final product.
The cassava slurry coming from the AMPU is refined in the MRU which takes out most of the fibers and then subsequently dewatered in a decanter that is fitted in the AMPU to produce cassava starch cake.
This unit allows the extraction of cassava fibres from the cassava cake resulting in a so-called cassava starch cake which has much better drying characteristics than the cassava cake, halving the drying costs while making a higher grade product called cassava starch flour.
The MRU fits in a 20 ft. container which is based on its own dedicated chassis trailer. The unit is connected by quick coupling piping (through the wall) with the rasper outlet (IN to the MRU) and with the decanter inlet (OUT from the MRU) inside the AMPU.
The MRU takes its power from the AMPU genset and water comes from 2 or 3 boreholes depending on local circumstances. The MRU (and also the AMPU) have been designed to re-use water as much as possible from within its own process.