How to save energy in industry? The quantity of steam used in each activated carbon regeneration can be reduced using the latent heat in the solvent-steam mix (desorbate) exiting the adsorber during regeneration. In the first few minutes the steam fully condensates, since all the heat is used to heat the adsorber and the carbon. Afterwards the steam – only acting as a means of transport – is still available as steam coming from the adsorber.
A slight vacuum degree produced by a thermocompressor (fed with cold 8-9 bar steam) and the heat supplied by the desorbate, allow steam production when the previously-accumulated condensate re-evaporates.
The produced steam, mixed with the fresh steam feeding the thermocompressor, represents the steam flowrate necessary for the activated carbon regeneration.
In this way, supplying an average of 0,7 kg of fresh steam at 8 bars generated with conventional boilers we can produce 1 kg of vacuum-sealed recovered steam (97°C), for a total of 1,7 kg of steam suitable for the regeneration (the quantity of fresh steam used in this phase is therefore just 41% of the one required by a traditional system).
Since energy recovery is impossible during the first regeneration phase, which lasts a third of the total regeneration time, the total steam consumption reduction will be 30% of the total consumption on average.