Open electrochemical reactor

The electrochemical reactors for continuous production are opened. A pump ensures circulation through the cell and the mass flow rate is controlled. The electrodes, anode and cathode have a large surface to ensure massive production and large current intensity is applied. The average current density is from 0.1 to 1 A cm 2. The produced bubbles are accumulated at the top of the cell. 

Also steady state calculations, performed in different applied flow and potential conditions, need still to be compared in full detail with measurements performed in the same conditions. It is believed however that it is already proven that the concepts work and will open new possibilities for bubble simulations in electrochemical reactors. 

THE PROBLEM An undivided parallel plate electrochemical reactor is used to carry out a mass transfer limited reaction. Mass transfer rates are enhanced with a packed or fluidized bed of electrochemically inert spheres. Compare the mass transfer rates and pressure drops encountered with those for the open channel. 

Two types of continuous flow solid oxide cell reactors are typically used in electrochemical promotion experiments. The single chamber reactor depicted in Fig. B.l is made of a quartz tube closed at one end. The open end of the tube is mounted on a stainless steel cap, which has provisions for the introduction of reactants and removal of products as well as for the insertion of a thermocouple and connecting wires to the electrodes of the cell. A solid electrolyte disk, with three porous electrodes deposited on it, is appropriately clamped inside the reactor. Au wires are normally used to connect the catalyst-working electrode as well as the two Au auxiliary electrodes with the external circuit. These wires are mechanically pressed onto the corresponding electrodes, using an appropriate ceramic holder. A thermocouple, inserted in a closed-end quartz tube is used to measure the temperature of the solid electrolyte pellet. 

These few examples grew out of the chest of treasures opened up by Galvani and by Volta. Diabetics will soon be able to check their glucose levels by glancing at a wrist meter that measures sugar content electrochemically. Tritium, an essential component of nuclear weaponry, may be made electrochemically at a fraction of the cost of its production in a nuclear reactor. 

On the other hand, well engineered manufacturing operations depend on the availability of manipulated variables for real-time feedback control. These variables usually operate at macroscopic length scales (e.g. the power to heat lamps above a wafer, the fractional opening of valves on flows into and out of a chemical reactor, the applied potential across electrodes in an electrochemical process). The combination of a need for product quality at the molecular scale with the economic necessity that feedback control systems utilize macroscopic manipulated variables motivates the creation of methods for the simulation, design and control of multiscale systems. 

Another advantage of this enzyme-catalyzed route to colloidal PAn salts is the considerably higher pH that can be employed compared to the previous chemical and electrochemical polymerization methods. Horseradish peroxidase immobilized on chitosan powder as a solid support has also been found to catalyze the H202 oxidation of aniline to a similar PAn/PSS product, opening up the prospect of enzyme reuse and the design of enzyme reactors for PAn synthesis.104... 

A second obvious area of application is in continuous flow analysis or flow injection analysis systems, in which the immobilized molecules form reactors that can be readily inserted and replaced in a flow analysis manifold. The physical form of the enzymes varies widely packed-bed reactors are often used, but open-tube wall reactors and membrane reactors have also been investigated. A principal advantage of all such systems is that they can use all the optical or electrochemical detectors routinely used in flow analysis. However, the problems of producing stable and robust immobilized enzyme reactors have proved more intractable than many researchers hoped, and other advances (e.g.. the use of more sensitive detectors, improved availability of low-cost soluble enzymes) have minimized the advantages of using solid phase enzymes. 

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