General Process Behavior

In the previous chapter the behavior of elementary transfer functions has been discussed in the frequency domain. Systems that are more complex are often composed of a series and/or parallel connection of these elementary transfer functions. In chapter 1 the use of diagrams was introduced to show the coherence between systems. In this chapter the behavior of the different processes will be explained in the time domain based on these diagrams, covering the entire range from elementary first-order lumped systems to complex distributed systems. In the following chapters 11-16 the behavior of different process units will be described based on this general process behavior. 

The dynamic behavior of systems can be divided into several categories  

These are processes or sections of processes, which can be assumed to be ideally mixed and consequently all state variables are only dependent on time and are independent of a certain location. Examples of these processes are ideally mixed reactors, evaporators and one-stage separators. These processes can be described by a combination of elementary balances  

These systems can be described by one elementary balance which refers to the accumulation of mass, energy or components. 

Many processes in the chemical indnstiy can be characterized by the interaction between two or more balances, such as the interaction between a mass and energy balance (evaporator) or a component balance and an energy balance (reactor). The dynamic behavior can be explained by the denorrrinator of transfer fnnction. The balances can exhibit an interaction to the extent that the dynarrric response starts to show oscillatiorrs. 

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Higher Cu exposures (Figures 4b, 4c, and 4d) cause the appearance of a second binding state, fi., with a desorption maximum at a temperature below that of the state. The kinetics of the desorption process of the state are approximately zero order, indicating that the rate or the desorption is independent of the Cu concentration on the surface. The general adsorption behavior and peak temperatures in Figure 4 are completely in agreement with the work of Christmann, et al. (34). 

Note The previous formulations for both normal and abnormal situations are very general and include inputs to the process as well as different types of perturbations (jumps) in normal process behavior. Later on in this chapter we will consider a reduced version of this formulation, since we will be mainly interested in the measurement bias detection and identification problem. 4k... 

We may limit the discussion to Case I without losing sight of the generality of behavior which characterizes all three processes. The system is determined by the initial concentrations of monomer, M0, initiator, P, and the equilibrium constants Kt and K. Its qualitative behavior is not affected by the simplifying assumption demanding Kx to be equal to K and therefore, for the sake of clarity, this is accepted in the present discussion. 

The general electrochemical behavior of surface-bound molecules is treated in Sect. 6.4. The response of a simple electron transfer reaction in Multipulse Chronoamperometry and Chronocoulometry, CSCV, CV, and Cyclic Staircase Voltcoulometry and Cyclic Voltcoulometry is also presented. Multielectronic processes and first- and second-order electrocatalytic reactions at modified electrodes are also discussed extensively. 

Let us examine somewhat generally the behavior of a typical system undergoing reaction at constant volume in a flask whose walls are thermo-statted. If initially the reaction mixture was transferred to the flask from some vessel at a lower temperature, there is a finite interval (for gases of the order of 10 to 30 sec) during which the temperature of the mixture reaches that of the flask walls. The processes responsible for this are conduction (both through the gas and across the walls to the thermostat) and convection. The convection arises from the original motion of the gas in... 

The general sequence for constructing Process Behavior Charts is the same for all types of data, but there is some variation depending upon whether attribute data (data you can count) or variable data (data on a scale) are involved. We ll show you the steps and some details for each type of Process Behavior Chart. 

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