Solvent Recovery
Absorption:
Solvent-laden air (SLA) resulting from the production process passes through deep static beds of activated carbon. The solvents are retained in the activated carbon pores and the cleansed air is discharged to the atmosphere, which is continuously monitored by an FID analyser calculating the total quantity of activated carbon.
Activated carbon regeneration:
The regeneration of activated carbons involves restoring the adsorptive capacity of saturated activated carbon by desorbing adsorbed contaminants on the activated carbon surface. The process generally follows these three steps:
1. Inertisation:
The saturated carbon contains oxygen that has to be eliminated before the solvent is vaporised and reaches high concentrations.
2. Heating and condensation:
During this heating phase, the activated carbon bed releases moisture. The moisture is condensed in a glycol water-fuelled system. The recovered solvent is then stored in an appropriate vat, to be used after undergoing the proper quality control. The beginning of the regeneration phase of each layer of activated carbon is done automatically by means of a PLC timer, which is activated when solvent concentration reaches a certain level, or manually, by the operator.
3. Distillation:
The distillation unit is made up by three columns, from which we obtain pure ethyl acetate, a mixture of high-boiling point products, an azeotropic mixture of ethyl acetate and water.