Reactors homogeneous batch

Figure 1-S Simple batch homogeneous reactor. [Excerpted by special permission om Ciiem. Eng., 6S 10), 211 (Oct W56). Copyright 1956 by McGraw-Hill, Inc., New Ywk. NY 10020.]...

Reactor designs are characterized as either homogeneous or heterogeneous. Typically, homogeneous reactors are well mixed stirred tanks (either batch or continuous), but can also be tubular reactors. They are widely used in the chemical industry from pilot plant to full-scale production. Examples include decomposition of azomethane, production of ethylene glycol, and the copolymerization of styrene and butadiene. 

Simple batch homogeneous reactors Closed tank... 

Two-Phase Liquid-Liquid Systems. Mhdng times for both liquid phases and the overall liquid-liquid mass-transfer rate are the most important issues for two-phase liquid-liquid homogeneous catalytic batch reactors. Residence time distributions and overall liquid-liquid mass transfer are the most important issues for two-phase liquid-liquid homogeneous catalytic CSTRs. 

For a homogeneous reactor, it is characteristic that just one phase, usually a gas or a liquid phase, is present. Chemical reactions thus take place in this phase. In this chapter, we will examine three reactors most commonly used industrially for homogeneous reactions a batch reactor (BR), a tube reactor, and a tank reactor. Figure 3.1 illustrates a BR. A BR is operated by at first charging the reactor contents with a reaction mixture that is usually heated to the reaction temperature, allowing the reaction to proceed until the desired conversion of the reactants has been reached. After this, the reactor vessel is emptied. 

In conclusion we would like to emphasize that our method is directly linked to the use of flow reactors and that most new chemical oscillators only oscillate in such reactors. Batch transient oscillatory reactions are now a minority since they call for higher kinetical complexity. In these latter some primary reactions must play roles analog to that of the flow in open reactor such as the supply, at appropriate rate, of active intermediate species and the scavenge of inhibitory end products over time long compared to the period of oscillations. In this respect the behaviour of the B.Z. reaction where more than 500 oscillations can be observed in batch condition is a truly exceptional situation which through of sent the early attempts to produce new homogeneous chemical oscillators in close reactors. Chemical oscillatory behaviour is probably still more ubiquitous than it appears now. There are certainly classes of oscillatory reactions not linked to bistability but there is not yet any practical systematic method to spot these reactions. 

Isotope Concentrations and Cost Breakdown for Batch-Operated Homogeneous Reactors ... 

En2yme techniques are primarily developed for commercial reasons, and so information about immobilisation and process conditions is usually Limited. A commercially available immobilised penicillin V acylase is made by glutaraldehyde cross-linking of a cell homogenate. It can be used ia batch stirred tank or recycled packed-bed reactors with typical operating parameters as iadicated ia Table 2 (38). Further development may lead to the creation of acylases and processes that can also be used for attaching side chains by ensymatic synthesis. 

In terms of cost and versatility, the stirred batch reactor is the unit of choice for homogeneous or slurry reactions and even gas/liquid reactions when provision is made for recirculation of the gas. They are especially suited to reactions with half-lives in excess of 10 min. Sam-... 

The coalescence-redispersion (CRD) model was originally proposed by Curl (1963). It is based on imagining a chemical reactor as a number population of droplets that behave as individual batch reactors. These droplets coalesce (mix) in pairs at random, homogenize their concentration and redisperse. The mixing parameter in this model is the average number of collisions that a droplet undergoes. 

Homogeneous reactions are those in which the reactants, products, and any catalysts used form one continuous phase (gaseous or liquid). Homogeneous gas phase reactors are almost always operated continuously, whereas liquid phase reactors may be batch or continuous. Tubular (pipeline) reactors arc normally used for homogeneous gas phase reactions (e.g., in the thermal cracking of petroleum of dichloroethane lo vinyl chloride). Both tubular and stirred tank reactors are used for homogeneous liquid phase reactions. 

The alternative to batch mode operation is continuous operation. In the continuous mode there is a continuous flow of medium into the fermentor and of product stream out of the fermentor. Continuous bioprocesses often use homogenously mixed whole cell suspensions. However, immobilised cell or enzyme processes generally operate in continuous plug flow reactors, without mixing (see Figure 2.1, packed-bed reactors). 

Under ideal conditions similar to homogeneous batch reactor case. 

Suppose a homogeneous, gas-phase reaction occurs in a constant-volume batch reactor. Assume ideal gas behavior and suppose pure A is charged to the reactor. 

This paper presents the physical mechanism and the structure of a comprehensive dynamic Emulsion Polymerization Model (EPM). EPM combines the theory of coagulative nucleation of homogeneously nucleated precursors with detailed species material and energy balances to calculate the time evolution of the concentration, size, and colloidal characteristics of latex particles, the monomer conversions, the copolymer composition, and molecular weight in an emulsion system. The capabilities of EPM are demonstrated by comparisons of its predictions with experimental data from the literature covering styrene and styrene/methyl methacrylate polymerizations. EPM can successfully simulate continuous and batch reactors over a wide range of initiator and added surfactant concentrations. 

The reaction between mono-octyl phthalate and i5tMx tanol (see Fig. 5.4-25) in the presence of a homogeneous catalyst (rert-butyl titanate) was studied in a batch reactor (Szarawara et al., 1991). This is the second step of the reaction between phthalic anhydride and o-octanol. First the ring is opened and mono-octyl phthalate is formed. Water is removed by evaporation as it is formed. The reaction was carried out at 174 °C. The initial concentration of mono-octyl phthalate was cpno = 1.85 mol/L and the ratio of initial concentrations of iio-octanol to mono-ooctyl phthalate coc.o/cph,o = 1.4. The reaction was... 

Runaway criteria developed for plug-flow tubular reactors, which are mathematically isomorphic with batch reactors with a constant coolant temperature, are also included in the tables. They can be considered conservative criteria for batch reactors, which can be operated safer due to manipulation of the coolant temperature. Balakotaiah et al. (1995) showed that in practice safe and runaway regions overlap for the three types of reactors for homogeneous reactions (1) batch reactor (BR), and, equivalently, plug-flow reactor (PFR), (2) CSTR, and (3) continuously operated bubble column reactor (BCR). 

An nth-order homogeneous liquid phase reaction is carried out in a batch tank reactor. 

At this point we wish to turn to a brief discussion of the types of batch and flow reactors used in industrial practice for carrying out homogeneous fluid phase reactions. Treatment of heterogeneous catalytic reactors is deferred to Chapter 12. 

The experiments of reactive distillation were carried out in a double-neck round-bottom flask working as a batch reactor. The reaction vessel was heated using a heating mantle and a magnetic stirrer was applied to create homogeneous slurry as reaction mixture. 

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