Electrolytic reactor

Cheng, H., Scott, K. and Christensen, P.A. (2004b) Design and operation of a solid polymer electrolyte reactor for electrochemical hydrodehalogenation. Chem. Eng. J. (Amsterdam) 102, 161-170. 

Principles and Applications of Solid Polymer Electrolyte Reactors for Electrochemical Hydrodehalogenation of Organic Pollutants... 

Fig. 13.3 The principle of a chlorine/alkaline solid polymer electrolyte reactor...

Another approach to reducing fraui-acids involves electrochemical hydrogenation with a palladium catalyst in a solid-state electrolyte reactor (10) where about 50% reduction in fraui-was observed compared with nickel at iodine values of about 90. 

The cross-flow geometry soon became a natural structural solution when developing compact fuel cells and solid-state electrolytic reactors. Fuel cell technology is an extensive part of chemical engineering science [38] and would require a chapter or book of its own to be described. 

The goal of using solid-state electrolytic reactors is not only to generate electrical power, but also to combine this with an industrially important catalytic reaction, such as dissociation of oxygen-containing compounds like NO [40,41], quantitative oxidation of NH3 to NO [42-44], oxidation of SO2 [45], and methanol [46], ethylene epoxidation [46], or Fischer-Tropsch synthesis [47]. The cross-flow reactor used in this type of study (Fig. 10) [48,49] has a solid electrolyte consisting of yttria-doped zirconia. The plates are electrically connected in series, with a varying number of plates in parallel. The oxidant flow channels... 

The following scheme was suggested as a possible network model to describe a real electrolytic processes. Reactors 1 and 2 are continuous-flow stirred-tank electrolytic reactors (CSTER), reactor 3 is a reactor for the recycling electrolyte and reactor 4 is collector in which no electrolytic process takes place. 

Let us consider a solid oxide electrolyte reactor in which one side ofthe membrane is in contact with ambient air, and the other side (referred to as the working electrode) is fed either by an inert or a reactive gas (a mixture of hydrogen, natural gas, hydrocarbons, CO, etc. and H2O and/or CO2). Figure 12.5 shows, in graphical terms, the voltage variation of the working electrode referred to air as a function of the current. 

Solid polymer electrolyte reactors have been examined previonsly for oxidation and organic electrochemical redaction of organic componnds [56, 72-78]. Ognmi and co-workers studied the electrochemical hydrogenation of nitrobenzene to aniline nsing a Cn-Pt cathode/Naflon mem-brane/Pt anode MEA [76] and the rednction of cyclo-octene, diethyl maleate, ethyl crotonate, and n-bntyl methacrylate (dissolved in either ethanol, diethyl ether, or n-hexane) with MEAs composed of Pt, An, or An-Pt cathode layers deposited onto the snrface of a Nation membrane [72]. In addition, electrochemical rednction of edible oils (snch as soybean or cottonseed) resnlts in a quite different prodnct [79]. 

Konishi, S., Maruyama, T., Okuno, K., Inoue, M. and Yamashita, A. 1998. Development of electrolytic reactor for processing of gaseous tritiated compounds. Fusion Eng. Des. 39 0 1033-1039. 

An, W., Hong, J.K.,Pintauro, P.N., 1998. Current efficiency for soybean oil hydrogenation in a solid polymer electrolyte reactor. Journal of Applied Electrochemistry 28,947-954. 

The design of electrochemical reactors for direct oxidation of SO2 generally requires high interfacial areas and high mass transfer coefficients are required in the absorption stage. The absorption may be carried out in the electrolytic reactor, as an inner cell process or in an external scrubber, as an outer cell process. 

The overall rate of chemical change at an electrode process depends on the current density, j (the cell current, /, divided by the electrode area. A) for the desired reaction and the selectivity of the chemical change. The latter is usually discussed in terms of the current efficiency, , for the desired chemical change and is defined as the fraction of the charge passed used in the desired reaction. The space-time yield, Tst for n electrolytic reactor may be written... 

Cheng H, Scott K, Christensen PA (2005) Paired electrolysis in a solid polymer electrolyte reactor -simultaneously reduction of nitrate and oxidation of ammonia. Chem Eng J 108 257-268... 

It follows that there will be little descriptive matter about industrial practice in this book. Instead emphasis is placed on a quantitative analysis of processes occuring in various industries. The aim is not only to provide either directly or by means of references a systematic treatment of design procedures for electrolytic reactors but also to emphasize their interaction with other units of the flow sheet, as indicated in Section 1.1. It must be stressed, however, that our intention is to provide a guide to process development, not a textbook. 

The assumption of a one-dimensional current flow is adequate for most electrolytic reactors that have narrow interelectrode spaces. Appropriate mean cross-sectional area A and equivalent electrolyte length / must be assigned. For electrodes of nonplanar cross section McMullin describes procedures to estimate A and 1. 

It is usual for electrolytic reactors, where the reaction rate is expressed in terms of current density, to denote ohmic losses in the electrolyte in the form ... 

An electrolytic reactor or cell is a device in which one or more chemical species are transformed to alternative states with an associated energy change. There are many kinds of reactors selection of an appropriate one is dealt with in Chapter 5. The form a reactor takes depends largely on the number of phases involved and the energy requirements. The size depends on the rate of reaction we shall see that a reactor model can provide important answers about this rate. The reaction rate of an electrolytic reactor is defined by the possible current density, expressed in terms of reaction models in Chapter 3. 

There are many ways to classify cell designs. One is based on reactor engineering principles. Another is specific to electrolytic reactors, based on the nature of the working electrode, the method of current supply to individual cells, and the arrangement of the flow of electrolyte through the cell. 

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