Recycling with steam
Recycling with steam is common in the alcohol industry and is done in the following manner:
1. The filter is back-flushed with hot water. This is done downward from above, since these carbon filters always works upward from below.
2. After that, the steam is connected and forced through the carbon. This too is done downward from above. The steam is 120-130°C and very soon the carbon is heated to the same temperature. All fusel oils and impurities are flushed out of the carbon pores.
3. Finally the carbon is back-flushed and is ready for use again.
This can be done in smaller scale. A stainless steel tube, 3 inch wide and 1.5 meter long is filled with used, granulated activated carbon. Then steam from a hobby steam cleaner is steemed from above and downwards. When the steam cleaner have used up 3 liters of water (small steam cleaners have to be refilled), the carbon is regenerated. In fact, it is just as easy to build a complete filtering unit. First one use it as a filter from bottom to top. Then regenerate it with steam. The activated carbon stays in the tube. This can be used by micro distilleries to and can also be scaled up.
If filter is not in use for weeks, carbon is taken our and dried – or keept in the filter in 70% alcohol. If keept in water, bacterias will grow there.
When used as a filter one supply the alcohol from a height that is higher then the filter. Filtering speed can be regulated with hight (pressure) of input container, size of tube. By reducing input speed, with a valve or similar, one slow down filtration and it works much better because longer contact time shortens the MTZ.