Granulated activated carbon is used in thick layers, usually between 1.5-2.5 meters where the filtering takes place through the carbon. Inside the carbon, the alcohol runs through the macro pores in the granules. The layer is constructed by filling a pipe with
activated carbon. For easily purified liquids, like water, a layer of 5-10 cm should be enough. Alcohol normally needs 1.5 meters. It does not matter if the layer (the length of pipe used) is higher, but if it is too thin, then purification will not take place. The pipe must be at least 38 mm in diameter otherwise a “wall effect” will be created and the alcohol runs past the carbon along the wall, without being purified.For the filtering to really take place in the carbon, the pipe must be free from air. This means that the purification must take place in one continuous flow. The pipe must not be allowed to run dry. The carbon must also be saturated so that the alcohol immediately
runs through the carbon. Neither should any channels be allowed to form in the carbon filled in the pipe. This will happen if you pour dry carbon into the pipe and then in the alcohol. Channels are formed in the carbon, through which the alcohol can escape unpurified, as in the film of air between the carbon granules. The carbon bed must be correctly started.When water or alcohol is filtered through carbon, the first thing to happen is that the soluble substances left in the pores from manufacturing are dissolved. These are the substances that have not become gas and evaporated, and have not been rinsed out
after manufacturing. It would be too expensive to completely rid the carbon of the substances. All industrial filters are started up despite this, and the carbon is rinsed through before use. Everyone who works with activated carbon knows that these
substances are present in the carbon.