Design of a slurry electrode reactor system

Abstract

A ’slurry electrode‘ is a suspension of particles with large double-layer capacity, such as activated carbon, in an electrolyte solution. These particles transfer charge from an electrochemical cell to an external reactor, where a substance is oxidized or reduced, and are recharged in the cell. The circulated particles must be separated from the solution of the reaction product. Various aspects of a system consisting of an electrochemical cell, a reactor, and a sedimentation vessel for separation are discussed.

For the reactor the following aspects are considered: rate of influx, residence time in the reactor, size of the reactor, concentration of particles in the suspension, rate and degree of conversion, flow rate of particles and single or cascade reactors.

The transport of charge by the particles determines the current flowing in the electrochemical cell as well as the rate of conversion, or, for a given degree of conversion, the maximum initial concentration. Specific, and yet unsolved, problems of the cell are examined. These result from the contact between the particles and the feeder electrode, of which either the duration is too short or the resistance is too great.

Possible application of a slurry electrode working in steady state conditions is considered.