Ideal reactors batch reactor

This chapter treats the effects of temperature on the three types of ideal reactors batch, piston flow, and continuous-flow stirred tank. Three major questions in reactor design are addressed. What is the optimal temperature for a reaction How can this temperature be achieved or at least approximated in practice How can results from the laboratory or pilot plant be scaled up ... 

Chemical kinetics plays a major role in modeling the ideal chemical batch reactor hence, a basic introduction to chemical kinetics is given in the chapter. Simplified kinetic models are often adopted to obtain analytical solutions for the time evolution of concentrations of reactants and products, while more complex kinetics can be considered if numerical solutions are allowed for. 

In the case of ideally stirred batch reactor the mass balance leads to the expression... 

For the purely discontinuous reactor operation the ideally mixed batch-reactor, BR, is used. All educts and solvents are charged initially. Under agitation the mixture is warmed up until the desired process temperature is reached. The reactor is operated at this temperature for a certain reaction time tg, which corresponds to the desired conversion. This is followed by an operational phase to isolate the product. From a safety technical point of view the BR is the reactor causing a maximum of problems, for... 

Basic Design ofEnv me Reactors Under Ideal Conditions. Batch Reactor Continuous Stirred Tank Reactor Under Complete Mixing Continuous Packed-Bed Reactor Under Plug Flow Regime... 

We already derived the performance equations for the three ideal reactors, batch, plug-flow, and mixed-flow. The batch and plug-flow reactors are exactly comparable, and the reaction time tin a BR is related to the residence time 1 at the corresponding axial position in a PFR by... 

For an ideally mixed batch reactor, the equation for mass transport by convection is not needed but, apart from this exception, we have to account for convection and in many cases also for diffusion. 

The hrst part serves as an introduction to the subject title and contains chapters dealing with history, process variables, basic operations, chemical kinetic principles, and stoichometry and conversion variables. The second part of the book addresses traditional reactor analysis chapter topics include batch, CSTRs, and tubular flow reactors, plus a comparison of these classes of reactors. Part IH keys on reactor applications that include thermal elfects, interpretation of kinetic data, non-ideal reactors, and reactor design. The book concludes with other reactor topics chapter titles include catalysis, catalytic reactions, fluidized and fixed bed reactors, biochemical reactors, open-ended questions, and ABET-related topics. An Appendix is also included. 

Insertion of these rate laws in mass balances of ideal reactors (batch/plug flow or transient CSTR) leads to systems of semi-linear, first-order, partial differential equations, with a single family of characteristics [Eq. (139)]. 

Problem 3-3 (Level 2) In an ideal, semi-batch reactor, some of the reactants are charged initially. The remainder of the reactants are fed, either continuously or in slugs, over time. The contents of the reactor are mixed vigorously, so diat there are no spatial gradients of temperature or concentration in the reactor at any time. 

Use the design equation for an ideal, isothermal batch reactor to show that Ca = CaoS -... 

Assume that the container behaves as an ideal, isothermal, batch reactor. Since the reaction occurs in the liquid phase, constant density (constant volume) can be assumed. The subscript A will be used to denote Btz. 

In an experiment in an ideal, isothermal batch reactor, 0.25 g of 5 wt.% Ru/IRA-400 resin was dispersed in an aqueous solution containing 6 g NaBHt, 3 g NaOH, and 21 g HzO. The following data were obtained at 25 °C. 

To measure the thermal reaction power <7 of a real reaction, the online calorimeter is placed in the circulation of an ideally mixed batch reactor with 15 L volume. In the batch reactor is installed an electric heater of the same design as described in Sect. 2.1.1. 

The same four operating steps are used with the complex batch reactor as with the simple batch reactor. The powerhil capabiUties of the complex batch reactor offset their relatively high capital cost. These reactors can operate at phenol to alkene mole ratios from 0.3 to 1 and up. This abiUty is achieved by designing for positive pressure operation, typically 200 to 2000 kPa (30 to 300 psig), and for the use of highly selective catalysts. Because these reactors can operate at low phenol to alkene mole ratios, they are ideal for production of di- and trialkylphenols. 

Batch reactors often are used to develop continuous processes because of their suitabiUty and convenient use in laboratory experimentation. Industrial practice generally favors processing continuously rather than in single batches, because overall investment and operating costs usually are less. Data obtained in batch reactors, except for very rapid reactions, can be well defined and used to predict performance of larger scale, continuous-flow reactors. Almost all batch reactors are well stirred thus, ideally, compositions are uniform throughout and residence times of all contained reactants are constant. 

The hquid-phase chlorination of benzene is an ideal example of a set of sequential reactions with varying rates from the single-chlorinated molecule to the completely chlorinated molecule containing six chlorines. Classical papers have modeled the chlorination of benzene through the dichlorobenzenes (14,15). A reactor system may be simulated with the relative rate equations and flow equation. The batch reactor gives the minimum ratio of... 

A useful classification of lands of reaclors is in terms of their concentration distributions. The concentration profiles of certain limiting cases are illustrated in Fig. 7-3 namely, of batch reactors, continuously stirred tanks, and tubular flow reactors. Basic types of flow reactors are illustrated in Fig. 7-4. Many others, employing granular catalysts and for multiphase reactions, are illustratea throughout Sec. 23. The present material deals with the sizes, performances and heat effects of these ideal types. They afford standards of comparison. 

Under ideal conditions similar to homogeneous batch reactor case. 

Heat and mass transfer limitations are rarely important in the laboratory but may emerge upon scaleup. Batch reactors with internal variations in temperature or composition are difficult to analyze and remain a challenge to the chemical reaction engineer. Tests for such problems are considered in Section 1.5. For now, assume an ideal batch reactor with the following characteristics ... 

The ideal, constant-volume batch reactor satisfies the following component balance ... 

There are two important types of ideal, continuous-flow reactors the piston flow reactor or PFR, and the continuous-flow stirred tank reactor or CSTR. They behave very diflerently with respect to conversion and selectivity. The piston flow reactor behaves exactly like a batch reactor. It is usually visualized as a long tube as illustrated in Figure 1.3. Suppose a small clump of material enters the reactor at time t = 0 and flows from the inlet to the outlet. We suppose that there is no mixing between this particular clump and other clumps that entered at different times. The clump stays together and ages and reacts as it flows down the tube. After it has been in the piston flow reactor for t seconds, the clump will have the same composition as if it had been in a batch reactor for t seconds. The composition of a batch reactor varies with time. The composition of a small clump flowing through a piston flow reactor varies with time in the same way. It also varies with position down the tube. The relationship between time and position is... 

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