Batch reactors stoichiometry

Since the volume depends on conversion or time in a constant pressure batch reactor, consider the mole balance in relation to the fractional conversion X. From the stoichiometry. 

The following data were collected in an isothermal, constant-volume batch reactor. The stoichiometry is known and the material balance has been closed. The reactions are A B and A C. Assume they are elementary. Determine the rate constants kj and kn-... 

Tubular reactors are used for some polycondensations. Para-blocked phenols can be reacted with formalin to form linear oligomers. When the same reactor is used with ordinary phenol, plugging will occur if the tube diameter is above a critical size, even though the reaction stoichiometry is outside the region that causes gelation in a batch reactor. Polymer chains at the wall continue to receive formaldehyde by diffusion from the center of the tube and can crosslink. Local stoichiometry is not preserved when the reactants have different diffusion coefficients. See Section 2.8. 

Based on the above scheme and data concerning rates of individual reactions, fictitious experimental results for a batch reactor were generated in the form of initial and final concentrations for all components of the reaction mixture (see Table A-1). Identify the stoichiometry based on these data. The desired precision for 3 is 10 ... 

A constant volume batch reactor is used to convert reactant. A, to product, B, via an endothermic reaction, with simple stoichiometry, A —> B. The reaction kinetics are second-order with respect to A, thus... 

The liquid phase hydrolysis reaction of acetic anhydride to form acetic acid is carried out in a constant volume, adiabatic batch reactor. The reaction is exothermic with the following stoichiometry... 

One of the last two equations gives the relationship between Cv and CA at any time in a plug flbw or batch reactor. The stoichiometry of the system provides the additional information necessary to describe completely the system composition. 

The reaction system, 2A = B = > C, has been studied in a constant volume, batch reactor with the tabulated results. Assuming the orders conform to the stoichiometry, find the specific rates. 

The batch conversion of wood fuels with the following conversion concept overfired, updraft, fixed horizontal grate, and batch reactor, has proven to be highly dynamic and stochastic with respect to mass flow and stoichiometry of conversion gas as well as the air factors of the conversion and combustion system. 

Aqueous A at a concentration C o = 1 mol/liter is introduced into a batch reactor where it reacts away to form product R according to stoichiometry A R. The concentration of A in the reactor is monitored at various times, as shown below ... 

We are planning to operate a batch reactor to convert A into R. This is a liquid reaction, the stoichiometry is A R, and the rate of reaction is given in Table P5.21. How long must we react each batch for the concentration to drop from C o = 1.3 mol/liter to C / = 0.3 mol/liter ... 

At 100°C pure gaseous A reacts away with stoichiometry 2A a constant volume batch reactor as follows ... 

In general the stoichiometry can be messy with fractional yields changing with composition. Treatment of that case can be difficult. We d like therefore to make the simplification that all

mixed flow, or for the exponential growth period of batch reactors, otherwise it is questionable. 

Most combustion processes are chain-branching, but other examples of chain-branching reactions are also found in industrial systems. Chain-branching reaction systems are potentially explosive, and for this reason great care must be taken to avoid safety hazards in dealing with them. The explosion behavior of gaseous fuels as a function of stoichiometry, temperature, and pressure has been an important research area [241]. Experimental data are typically obtained in a batch reactor, a spherical vessel immersed in a liquid bath maintained at a specific temperature. The desire to understand the explosion behavior of various... 

The same general conclusions apply since backmixing of products with reactants should be avoided, a tubular plug-flow reactor or a batch reactor is preferred. However, there is one respect in which a series reaction involving a second reactant B does differ from simple series reaction with one reactant, even when the orders are the same. This is in the stoichiometry of the reaction the reaction cannot proceed completely to the product Q, even in infinite time, if less than two moles... 

In the usual case, t and ain will be known. Equation (1.49) is an algebraic equation that can be solved for aout. If the reaction rate depends on the concentration of more than one component, versions of Equation (1.49) are written for each component and the resulting set of equations is solved simultaneously for the various outlet concentrations. Concentrations of components that do not alfect the reaction rate can be found by writing versions of Equation (1.49) for them. As for batch and piston flow reactors, stoichiometry is used to relate the rate of formation of a component, say Sl-c, to the rate of the reaction SI, using the stoichiometric coefficient vc, and Equation (1.13). After doing this, the stoichiometry takes care of itself. 

The design of chemical reactors encompasses at least three fields of chemical engineering thermodynamics, kinetics, and heat transfer. For example, if a reaction is run in a typical batch reactor, a simple mixing vessel, what is the maximum conversion expected This is a thermodynamic question answered with knowledge of chemical equilibrium. Also, we might like to know how long the reaction should proceed to achieve a desired conversion. This is a kinetic question. We must know not only the stoichiometry of the reaction but also the rates of the forward and the reverse reactions. We might also wish to know how much heat must be transferred to or from the reactor to maintain isothermal conditions. This is a heat transfer problem in combination with a thermodynamic problem. We must know whether the reaction is endothermic or exothermic. 

Determine the conversion for an isothermal batch reactor using the stoichiometry of Example 5-1 and the same values of initial concentrations of A, B, C, and D in a reactor volume of 1 liter operating for 4 minutes. The rate constant is k = 105[(liter)2/(gmol2 min)]. 

Kinetic steps are best identified by measuring the initial products formed from individual species (including postulated intermediates) or from simple mixtures. Isotopically labeled species have proved useful in such experiments. Initial products of homogeneous processes are observable in batch reactors at sufficiently short times or in flow reactors at points sufficiently near the inlet. The most advanced systems for initial product detection are molecular beam reactors (Herschbach 1976 Levine and Bernstein 1987) in which specific collisions are observed. Each of these techniques restricts the number of contributing reactions in a given experiment, so that their stoichiometry and rates can often be inferred. 

E Related material This problem uses the mole balances developed in Chapter 1 for a batch reactor and the stoichiometry and rate laws... 

After selecting the chromatographic system the operation mode of the batch reactor has to be chosen. High productivities require a high throughput. Therefore, pulsed operation is used (Fig. 8.8). Reactants are supposed to be injected as a rectangle pulse of period tcic le and duration tinj. These parameters are strongly affected by the reaction kinetics, reaction stoichiometry and adsorption isotherm. 

From stoichiometry for a constant-volume batch reactor, we obtain... 

Concentration-Time Data. We will now use nonlinear regression to determine the rate law parameters from concemraiion-time data obtained in batch experiments. We recall that the combined rate law-stoichiometry-mole balance for a constant-volume batch reactor is... 

Equation 2.45 applies at every instant of time in a batch reactor. Whether or not there are spatial variations within the reactor makes no difference. All batch reactors satisfy ihe global stoichiometry of Equation 2.45... 

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