Solvent Recovery / Carbon Adsorption

A typical solvent recovery process consists of an activated carbon adsorption unit with two, but as many as seven adsorber units, and if required, an air stripper or distillation unit.

Solvent-laden air passes through a number of adsorber vessels in parallel or series flow where the solvent vapors are adsorbed by the activated carbon. Once the carbon becomes saturated and solvent starts to slip, as detected by an optional gas analyzer, the solvent-laden air is routed to a freshly regenerated stand-by adsorber and the saturated adsorber is regenerated.

Solvents are recovered by regenerating the activated carbon on-site via steam or hot nitrogen. Steam heats the carbon and strips the solvent from it. The steam and solvent vapor are then condensed in a water or air cooler condenser and drained to a separator. Water immiscible solvents (i.e. toluene, Methylene chloride) may be separated by simple decantation or distilled to purify them further, with the solvent being returned to the process for re-use, resale, or disposal; the resulting water layer may be disposed of/reused as is or may be treated in an air stripper or distilled to remove any dissolved solvent before disposal or reuse. Solvents that are water miscible are separated from the water and purified in a distillation system. When heated nitrogen is used to strip the solvent from the carbon, the solvent is condensed from the nitrogen stream at low temperature (~ -20 degrees C.).

Carbon adsorption is also a cost-effective alternative VOC/HAP emission system for manufacturing processes that emit halogenated or nitrogenated solvents. When oxidized, these solvents lead to the production of acid gases, such as HC1, HF, NOX , or dioxins/furans, which are pollutants that would require additional equipment to remove them from the oxidizer exhaust gas before venting to the atmosphere. The equipment required to process these by-products would require additional capital investment.

Contact us today to learn more about MEGTEC cost-effective solvent recovery and carbon adsorption solutions.