The prototype consists of different parts that are all connected to create a continuous flow. Each part will be explained separately, including calculation done to decide the dimensions of the prototype design.
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Article
Still
For the prototype, the batches used have a mass of 10 kg. This number does not have any scientific importance except that is an easy number for calculations. Lemongrass has moisture content of 50.0%, so one batch holds 5 kg of water and 5 kg of bone dry material. We can neglect the amount of lemongrass oil in these calculations, because this is very small amount compared to the 10 kg. The… -
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Cooling unit
Because the maximum steam temperature will be 120 degrees Celsius, a big cooling unit is not needed. A spiral from the top of the still to the separator will do. There is no cooling water needed. By making an easy cooling unit, the temperature of the water that goes in the separator will still be around 80 degrees Celsius. This water will be led back into the circuit to reduce energy loss. The… -
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Separator
After the distillation and the cooling down of the oil and the water, the oil needs to be separated from the water. To establish this, a separator unit is needed. To accomplish the best results, two different separator designs were made, both based on the same law. This law is called Stokes’ law, as stated here: The vertical velocity can be calculated easy because all the numbers are known. ρ w… -
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Heat source
At the moment there are solar panels in the village. These panels provide enough energy for the prototype, and we are allowed to use the panels. If the project will be scaled up, more solar panels must be installed to provide the distillation units with energy. To use this energy to produce steam, a boiler is used. As calculated before, 4,17 kg/hr steam need to be produced. A boiler with a power… -
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Pump
To achieve a continuous flow, water circulation is needed. To get this water circulation, a pump is installed. Because it is just a small flow rate (4,17 kg/h) a small pump will do. Think about a pump with a power of 6W. This is enough to pump 400 kg/h. -
Article
Steam Sparger
It is important that the steam is sparged equally over the lemongrass, so the oil will be withdrawn from all the grass. For this a special sparger is designed, which can be seen below. There are small holes on top of the 4 tubes so the steam will be spread equally over the entire still. This will improve the efficiency of the still, and no grass will be wasted because the steam does not reach it.