Updated: July 2002
Pulse Bed Activated Carbon Adsorption System1. Purpose
Activated carbon has found wide use in liquid and gas phase applications. In particular, granular activated carbon has been used in various areas of application such as cane sugar and dextrose decolorization, wastewater treatment (COD removal, decolorization, etc.), city and industrial water treatment (odor removal), and sodium glutamate. Granular activated carbon is often used for the above-mentioned applications in the so-called pulse bed mode of operation. Spent granular activated carbon which has adsorbed impurities is regenerated with a carbon regeneration furnace, in which adsorbates (organics) are decomposed in a water gas reaction at furnace temperature of 900ºC or so. Granular activated carbon thus rejuvenated is reused repeatedly.
2. Performance
When used for the tertiary treatment of wastewater or sewage, granular activated carbon gives a COD removal ratio of 90% or more. Its decolorization efficiency for sugar solutions is 80% or more. When granular activated carbon is regenerated in a regeneration furnace, the rate of restoration in 90% or more in terms of its apparent density, iodine number, etc. The ratio of carbon loss upon its regeneration ranges from 3 to 5%.
3. Characteristics
In the pulse bed granular activated carbon adsorption system as shown, feed wastewater is passed upward through an adsorption column with the treated water being discharged from the top of the column. A given amount of carbon is removed from the adsorption column once a day or so. Simultaneously, the same amount of regenerated carbon is fed to the top of the adsorption column. In this way, feed wastewater and carbon come into contact with each other in a counter-current manner, achieving a very efficient utilization of carbon. Besides the cylindrical, multi-hearth regeneration furnace as shown, regeneration furnaces of fluidized-bed type and rotary kilns are also used for the carbon regeneration depending upon the nature of carbon application and the quantity of carbon to be regenerated at a time.
4. Flow Diagram
