Updated: July 2002

1. General

A most outstanding feature of this method is that cycling times of adsorption and desorption are about 10 minutes respectively. This owes to the fact that diameter of the activated charcoal fiber is 15µm to 20µm, which is smaller by hundreds first than few millimeters of an activated charcoal used in a fixed bed. As a result, a solvent gas is adsorbed and desorbed at a higher rate with shorter break band, saving the quantity of activated charcoal.

2. Features

1) Highly efficient adsorption
Organic solvents contained in exhaust gas are adsorbed and purified efficiently by the activated charcoal fiber.
2) Recovery of high quality solvent
Adsorption and desorption in short time gives less thermal effects on the solvent, so that high purity solvent can be recovered.
3) Lost cost of equipment
Since a recovered chlorine-containing solvent has no HCl as a by-product due to low pH of clarified water, there is no need to use a high grade corrosion-resistant material, saving equipment costs.

3. Process (Refer to flow sheet)

The flow chart illustrated below shows adsorption in the first activated charcoal tower and desorption in the second activated charcoal tower. The two activated charcoal towers repeat adsorption and desorption alternately. When gas containing a solvent enters an activated charcoal tower, the solvent is adsorbed from the gas while it passes the cylindrically rolled activated charcoal fiber elements from its outer to inner circumference and the processed gas is discharged through top of the system as purified gas. Another activated charcoal tower blows water vapor through inter circumference of the activated charcoal fiber element to desorb the adsorbed solvent, and mixture of the solvent vapor and water vapor is introduced into the capacitor through outer circumference of the element and recovered as a high purity solvent after being separated from clarified and cooled water.

Flow sheet