Reactor batch-type

Efficiency of Intermediate Formation. The variation of the efficiency of a primary intermediate with conversion of the feed hydrocarbon can be calculated (22). Ratios of the propagation rate constants ( 2 / i) reactor type (batch or plug-flow vs back-mixed) are important parameters. 

Reactor type Batch stirred tank reactor Loop reactor... 

Chemical Kinetics, Tank and Tubular Reactor Fundamentals, Residence Time Distributions, Multiphase Reaction Systems, Basic Reactor Types, Batch Reactor Dynamics, Semi-batch Reactors, Control and Stability of Nonisotheimal Reactors. Complex Reactions with Feeding Strategies, Liquid Phase Tubular Reactors, Gas Phase Tubular Reactors, Axial Dispersion, Unsteady State Tubular Reactor Models... 

Polymer production technology involves a diversity of products produced from even a single monomer. Polymerizations are carried out in a variety of reactor types batch, semi-batch and continuous flow stirred tank or tubular reactors. However, very few commercial or fundamental polymer or latex properties can be measured on-line. Therefore, if one aims to develop and apply control strategies to achieve desired polymer (or latex) property trajectories under such a variety of conditions, it is important to have a valid mechanistic model capable of predicting at least the major effects of the process variables. 

Multiple Reactions—Choosing a reactor type to obtain the best selectivity can often be made by inspection of generalized cases in reaction engineering books. A quantitative treatment of selectivity as a function of kinetics and reactor type (batch and CSTR) for various multiple reaction systems (consecutive and parallel) is presented in [168]. 

In reactions with parallel steps of different reaction orders or with sequential steps, selectivities depend on the reactor type. Batch and plug-flow tubular reactors give higher selectivities to the product formed by the parallel step of higher order, or to the first product in a step sequence, than do continuous stirred-tank reactors. 

Solid catalysts can be used in all of the major reactor types, batch, semibatch, continuous stirred tank and tubular. In the first three cases particulate (powder) catalysts would be appropriate, whereas with the tubular reactor the catalyst would often need to be formed into pellets.8,9... 

Chapter 4. In Chapter 4 we develop the material balances for the three reactor types batch (and semi-batch), contmuous-stirred-tank,... 

Reactor Type Batch Stirred Tank Reactor Loop Reactor... 

Eig. 2. Efficiency to a primary intermediate as % of maximum (zero conversion) efficiency x axis is feed conversion. Parameters are oxidation rate-constant ratios ( 2 / i) for primary intermediate vs feed and reactor type A, plug-flow or batch B, back-mixed. 

Specific reactor characteristics depend on the particular use of the reactor as a laboratory, pilot plant, or industrial unit. AH reactors have in common selected characteristics of four basic reactor types the weH-stirred batch reactor, the semibatch reactor, the continuous-flow stirred-tank reactor, and the tubular reactor (Fig. 1). A reactor may be represented by or modeled after one or a combination of these. SuitabHity of a model depends on the extent to which the impacts of the reactions, and thermal and transport processes, are predicted for conditions outside of the database used in developing the model (1-4). 

Fig. 1. Reactor types (a) batch, (b) semibatch, (c) contiauous-flow stinred-tank, and (d) tubular.

Continuous-Flow Stirred-Tank Reactor. In a continuous-flow stirred-tank reactor (CSTR), reactants and products are continuously added and withdrawn. In practice, mechanical or hydrauHc agitation is required to achieve uniform composition and temperature, a choice strongly influenced by process considerations, ie, multiple specialty product requirements and mechanical seal pressure limitations. The CSTR is the idealized opposite of the weU-stirred batch and tubular plug-flow reactors. Analysis of selected combinations of these reactor types can be useful in quantitatively evaluating more complex gas-, Hquid-, and soHd-flow behaviors. 

The effect of physical processes on reactor performance is more complex than for two-phase systems because both gas-liquid and liquid-solid interphase transport effects may be coupled with the intrinsic rate. The most common types of three-phase reactors are the slurry and trickle-bed reactors. These have found wide applications in the petroleum industry. A slurry reactor is a multi-phase flow reactor in which the reactant gas is bubbled through a solution containing solid catalyst particles. The reactor may operate continuously as a steady flow system with respect to both gas and liquid phases. Alternatively, a fixed charge of liquid is initially added to the stirred vessel, and the gas is continuously added such that the reactor is batch with respect to the liquid phase. This method is used in some hydrogenation reactions such as hydrogenation of oils in a slurry of nickel catalyst particles. Figure 4-15 shows a slurry-type reactor used for polymerization of ethylene in a sluiTy of solid catalyst particles in a solvent of cyclohexane. 

The proceeding discussion of polymer composition was based on the assumption that essentially all polymer is formed in the organic phases of the reaction mixture. If a water-soluble monomer, such as some of the functional monomers, is used, the reactions taking place in the aqueous phase can contribute to variation in polymer composition. In fact, in extreme cases, water soluble polymer can be formed in the aqueous phase. This can happen in batch, semi-continuous or continuous reactors. The fate of functional monomers could be considerably different among the different reactor types, but detailed studies on this phenomenon have not been reported. 

Batch Mass Reactors. The batch-mass reactors used in these processes are of two types low conversion agitated kettles and high conversion static reactors with extended cooling surfaces. 

Like enzymes, whole cells are sometime immobilized by attachment to a surface or by entrapment within a carrier material. One motivation for this is similar to the motivation for using biomass recycle in a continuous process. The cells are grown under optimal conditions for cell growth but are used at conditions optimized for transformation of substrate. A great variety of reactor types have been proposed including packed beds, fluidized and spouted beds, and air-lift reactors. A semicommercial process for beer used an air-lift reactor to achieve reaction times of 1 day compared with 5-7 days for the normal batch process. Unfortunately, the beer suffered from a mismatched flavour profile that was attributed to mass transfer limitations. 

The protecting reaction of the enamino pyrrolidinone with t-butoxycarbonyl anhydride was carried out by mixing 4-(N-/-butoxycarbonyl)-4-aminomethylene-pyirolidin-3-one (Boc-AMP) with 1.2 molar equivalents of t-butoxycarbonyl anhydride (/-BoczO) to make l-(N-f-butoxycarbonyl)-4-(N-t-butoxycarbonyl)-ammomethylene-pyrrolidin-3-one (B0C2-AMP). Several types of reactors, including batch reactors, a continuous stirred tank reactor (CSTR),... 

For the various reactor types this equation simplifies in one way or another, and the resultant expression when integrated provides the basic performance equation for that type of unit. Since in batch reactor or operation, no stream is entering or leaving the reactor,... 

In this chapter, we describe several ideal types of reactors based on two modes of operation (batch and continuous), and ideal flow patterns (backmix and tubular) for the continuous mode. From a kinetics point of view, these reactor types illustrate different ways in which rate of reaction can be measured experimentally and interpreted operationally. From a reactor point of view, the treatment also serves to introduce important concepts and terminology of CRE (developed further in Chapters 12 to 18). Such ideal reactor models serve as points of departure or first approximations for actual reactors. For illustration at this stage, we use only simple systems. 

For a constant-volume batch reactor operated at constant T and pH, an exact solution can be obtained numerically (but not analytically) from the two-step mechanism in Section 10.2.1 for the concentrations of the four species S, E, ES, and P as functions of time t, without the assumptions of fast and slow steps. An approximate analytical solution, in the form of a rate law, can be obtained, applicable to this and other reactor types, by use of the stationary-state hypothesis (SSH). We consider these in turn. 

Our treatment of Chemical Reaction Engineering begins in Chapters 1 and 2 and continues in Chapters 11-24. After an introduction (Chapter 11) surveying the field, the next five Chapters (12-16) are devoted to performance and design characteristics of four ideal reactor models (batch, CSTR, plug-flow, and laminar-flow), and to the characteristics of various types of ideal flow involved in continuous-flow reactors. Chapter 17 deals with comparisons and combinations of ideal reactors. Chapter 18 deals with ideal reactors for complex (multireaction) systems. Chapters 19 and 20 treat nonideal flow and reactor considerations taking this into account. Chapters 21-24 provide an introduction to reactors for multiphase systems, including fixed-bed catalytic reactors, fluidized-bed reactors, and reactors for gas-solid and gas-liquid reactions. 

The operating parameter for the CSTR reactor is the liquid flow rate Q, which sets the residence time of the liquid through the ratio Q/VL and finally the conversion. From a production viewpoint, the (residence) time required to achieve a given conversion of S (or outlet concentration of S) is obtained by solving the set of Eqs. (33) and (34). The characteristics of the reactor kLa and VL must be known. In general, whereas VL is easily determined in a batch reactor, it is not in a CSTR. Rather, VL=fiLVR will be used, which requires knowledge of the liquid hold-up L. Correlations provide kLo (see below) and L characteristics for the different reactor types [3]. 

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