Impact/Purpose:

Carbonaceous adsorbents are used in many and diverse industrial processes to absorb organic solvent vapors from liquid and gas streams. When saturated they are regenerated by steam heating or by a heated stripping gas at moderate temperatures. After several saturation/regeneration cycles the adsorbent must be re-activated at high temperatures. Hot gas regeneration methods result in large volumes of relatively concentrated desorbed organic contaminant; yet the contaminant is still diluted in a large volume of stripping substance and the off-gas is usually incinerated. Steam regeneration with a low volume of stripping gas results in concentrated condensed solvent (which may be reused); but steam is only capable of moderate temperatures in practical systems. Electromagnetic heating with microwaves or radio frequency fields can accomplish both regeneration at moderate temperatures and re-activation at high temperatures. Simple and efficient collection of the desorbed organic solvent vapors is possible by condensation during regeneration, and the condensed solvent can be reused in the original process. The relatively high electrical conductivity of activated carbon particles often makes them poor candidates for microwave heating, however.

We will study radio frequency (RF) induction-coupled heating in a cylindrical adsorbent bed geometry, as is typically-used in industry. We propose a program of experimental studies at both laboratory and industrial scale and analytical numerical models to study and optimize RF induction adsorbent regeneration parameters in these important materials. We will study the feasibility of re-activation with RF induction. We will work closely with two industrial partners; Sorbent Control Technologies Inc., Elgin IL and 3M Austin Center, Austin IX.

Description:

We will use the experimental results to verify the numerical models and then use the models in parametric studies to determine the relative importance of each of the governing phenomena: electrical properties, heat transfer, RF applicator and adsorbent bed geometry. The models will be used to study the laboratory and industrial scale experiments in detail to identify common (or differing) trends between them. The results of both efforts will permit site-specific process design and optimization.

URLs/Downloads:

1999 Progress Report

URL

Record Details:

Record Type:PROJECT( ABSTRACT )

Start Date:09/01/1998

Completion Date:08/31/1999

Record ID: 57869

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Related Organizations:

Role :OWNER

Organization Name :UNIVERSITY OF TEXAS AT AUSTIN

Organization Name :GCHSRC

Citation :Austin

State :TX

Zip Code :78712

Project Information:

Approach :

We have performed preliminary experiments at 27 MHz in a solenoid coil with Sorb Tech AWX-13 activated carbon and Kreha BAC spheres. With simple equipment at relatively low powers we can heat dry test beds 3" in diameter to 150°C in a few minutes. RF induction heating is a viable regeneration option in these materials which can be employed even under vacuum heating is by direct volumetric absorption in the carbon particles and does not depend on a heat transfer medium. Temperature control is a critical issue, however. Heat transfer effects and non-uniform RF heating are co-existent phenomena which must be balanced with adsorbent geometry and residence time to obtain uniform regeneration.

Cost :$.00

Project IDs:

ID Code :R822721C679

Project type :Center