Electrochemical reactor energy balance

Energy Balance for a Closed Electrochemical Reactor under Galvanostatic... 

DISCUSSION ON MASS BALANCES AND ENERGY EFFICIENCIES IN AN ELECTROCHEMICAL REACTOR... 

The optimization of an electrochemical reactor calls for a full description of the process to accomplish the specific objective of the mass and the energy balances together with heat transfer considerations and thermodynamic and enthalpy changes that are related to the unit cell and the whole stack [1,2]. A full description of the kinetics of both processes, the electric properties of the cell components, and the hydrodynamic aspects of the entire cell is also required. 

The usual procedures for the conception of electrochemical reactors arise from the mass conservation laws and the hydrodynamic structure of the device. In fact, four types of balances can be considered energy, charge, mass, and linear movement quantity. Since the reactor must include the anodic and the cathodic reactions, it is possible to make a complete balance for the mass. The temperature also governs the stability of a chemical reactor, but in the case of an electrochemical device, the charge involved in the entire process has to be considered first [3-5]. 

Energy Balances and Hydrodynamic Conditions in the Electrochemical Reactor... 

Our interest in this chapter is with the mass and energy balances for chemical reactors, and in electrochemical cells. We consider first the mass and energy balances for tank and tubular reactors, and then for a general black-box chemical reactor, since these balance equations are an important application of the thermodynamic equations for reacting mixtures and the starting point for practical reactor design and analysis. Finally, we consider equilibrium and the energy balance for electrochemical systems such as batteries and fuel-cells, and the use of electrochemical cells for thermodynamic measurements. 

At this point it is instructive to compare the equations governing the flow, concentration, and potential fields in plasma and electrochemical reactors. The equations are (of course) identical except that an equation equivalent to the electron energy balance (Eq. 31) is not needed for electrochemical systems. The electroneutrality assumption is often made in plasmas (see Section 5.4.2) as is done in electrochemical engineering. 

As we said at the beginning of this section, an energy balance of the process is essential. A major user of energy is the electrochemical reactor, which will be considered next. 

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