Stoichiometry CSTRs

Kem Engineer has been asked to scale up an existing process to obtain an increased production capacity for compound B. At present the process is carried out in two CSTR s in series. The reaction involved has the following stoichiometry. 

An exothermic reaction with the stoichiometry A 2B takes place in organic solution. It is to be carried out in a cascade of two CSTR s in series. In order to equalize the heat load on each of the reactors it will be necessary to operate them at different temperatures. The reaction rates in each reactor will be the same, however. In order to minimize solvent losses by evaporation it will be necessary to operate the second reactor at 120 °C where the reaction rate constant is equal to 1.5 m3/kmole-ksec. If the effluent from the second reactor corresponds to 90% conversion and if the molal feed rate to the cascade is equal to 28 moles/ksec when the feed concentration is equal to 1.0 kmole/m3, how large must the reactors be If the activation energy for the reaction is 84 kJ/mole, at what temperature should the first reactor be operated ... 

To obtain a plot of heat generated, G(T), as a function of temperature, we must solve for X as a function of T using the CSTR mole balance, the rate law, and stoichiometry. For example, for a first-order liquid-phase reaction, the CSTR mole balance becomes... 

Combining the CSTR mole balance, the rate law, and stoichiometry, we have... 

To study a class of mechanisms for isothermal heterogeneous catalysis in a CSTR, Morton and Goodman (1981-1) analyzed the stability and bifurcation of simple models. The limit cycle solutions of the governing mass balance equations were shown to exist. An elementary step model with the stoichiometry of CO oxidation was shown to exhibit oscillations at suitable parameter values. By computer simulation limit cycles were obtained. 

The complex 0 contains nothing at all and is a mathematical artifice, not a species. [The pseudo-steps and thus the augmented network are not subject to the rules of stoichiometry and thermodynamics. For example, the CSTR network 14.1 violates microscopic reversibility in that it allows net circular reactions.]... 

This section analyses the second order reaction A + B P taking place in an isothermal CSTR-Separator-Recycle system. When the reactants are completely recycled, feasible operation is possible only if the ratio of reactants in the feed matches exactly the stoichiometry. For this reason, only one reactant feed may be on flow control (/a,o=1), while the feed flow rate of the second reactant (/b,o) must be used to control its inventory. Two possible control structures are discussed (Fig.13.22) flow control of the recycle stream of one reactant, or of the reactor effluent, respectively. 

The chlorite-iodide reaction has been found by Dateo et al. [79] and later by De Kepper et al. [80] to exhibit complex phenomena such as oscillations and bistability between steady states, when run in a continuous-flow stirred tank reactor (CSTR). The overall stoichiometry of the reaction is... 

A cascade of three identical CSTRs is currently employed to carry out an irreversible pseudo first-order reaction with water (W). The stoichiometry is... 

A battery of two identical CSTRs is currently employed to effect a reversible hydration reaction with a stoichiometry of the form... 

Stoichiometry, for example, in the case of nonstationary modes of reactor operation, needs another fundamental equation. For the CSTR the balance of a component is written as... 

The reaction of ethylene and chlorine in liquid ethylene dichloride solution is taking place in a CSTR. The stoichiometry of the reaction is,... 

We consider the iodate-arsenous acid system in a CSTR with arsenous acid in stoichiometric excess. A single stoichiometry describes the reaction at any time according to (I). 

For a CSTR. a coupled set of algebraic equations analogous to the PFR differential equations must be solved. These equations are arrived at from a mole balance on CSTR for every species coupled with the rates step and stoichiometry. For q liquid phase reactions occurring where N different species are present, we have the following set of algebraic equations ... 

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