Continuous stirred tank reactor in series

The decomposition reaction A -> B + C occurs in the liquid phase. It has been suggested that your company produce C from a stream containing equimolar concentrations of A and B by using two continuous stirred tank reactors in series. Both reactors have the same volume. The reaction is first-order with respect to A and zero-order with respect to B and C. Each reactor... 

Consider a system of two continuous stirred tank reactors in series (Figure PI.6), where the following endothermic reaction takes place ... 

Stoichiometry - Conversions Using Balanced Equations http //www.youtube.com/watch v=wySZDEbqbnM Two Continuous Stirred Tank Reactors in Series http //www.youtube.com/watch v=7RLQ9sHkdkk Balances on Multiple Units with Reaction https //www.youtube.com/watch v=tQyrSvll nc Extent of Reaction for Material Balances https //www.youtube.com/watch v=YusSUOjlOUk Three Methods for Solving Reactive Material Balances https //www.youtube.com/watch v=MSzTIRAv5io... 

Emulsion ABS resins produced in continuous stirred-tank reactors in series, are compared in performance with a standard polymer prepared in a conventional batch reactor. Polymer specifications are best met by using a 2-stage CSTR with interstage feed of the faster reacting monomer. 

Reactor type Continuously stirred tank reactors in series... 

Reactor type and size Continuously stirred tank reactors in series, 10 - 100 Continuously stirred tank reactors in series or batch reactors, 10 -100 m Batch or continuously stirred tank reactors in series, 10 - 50 m ... 

The theory behind the emulsion reaction is discussed in Chapter 10. A generic commercial process is shown in Fig. 13.7. The reactors are usually staidess or glass-lined steel tanks, similar to those used for suspension polymerization. In contrast to suspension polymerization, however, a proper emulsion is thermodynamically stable, and therefore emulsion polymerization can be run continuously. Newer processes often have several continuous stirred-tank reactors in series. 

The emulsion process can be modified for the continuous production of latex. One such process (68) uses two stirred-tank reactors in series, followed by insulated hold-tanks. During continuous operation, 60% of the monomers are continuously charged to the first reactor with the remainder going into the second reactor. Surfactant is added only to the first reactor. The residence time is 2.5 h for the first reactor where the temperature is maintained at 65°C for 92% conversion. The second reactor is held at 68°C for a residence time of 2 h and conversion of 95%. 

In the slurry process, the hydrolysis is accompHshed using two stirred-tank reactors in series (266). Solutions of poly(vinyl acetate) and catalyst are continuously added to the first reactor, where 90% of the conversion occur, and then transferred to the second reactor to reach hiU conversion. Alkyl acetate and alcohols are continuously distilled off in order to drive the equiUbrium of the reaction. The resulting poly(vinyl alcohol) particles tend to be very fine, resulting in a dusty product. The process has been modified to yield a less dusty product through process changes (267,268) and the use of additives (269). Partially hydroly2ed products having a narrow hydrolysis distribution cannot be prepared by this method. 

Example 4.5 Derive the state space representation of two continuous flow stirred-tank reactors in series (CSTR-in-series). Chemical reaction is first order in both reactors. The reactor volumes are fixed, but the volumetric flow rate and inlet concentration are functions of time. 

Consider a system of N continuous flow stirred tank reactors in series as shown in Figure 5-24. Although the concentration is uniform from one tank to another, there is a change in concentration as the fluid traverses between the CFSTRs. This is illustrated in Figure 5-25. The drop in concentration implies that the larger the number of CFSTRs in series, the closer the system would behave as plug flow. 

Continuous emulsion polymerization processes are industrially important for the large-scale production of synthetic polymer latexes, and have been used particularly where the solid polymer is to be recovered by coagulating the polymer latex. St-Bu rubber latex was one of the earliest latex products manufactured using continuous emulsion polymerization processes consisting of a number of stirred-tank reactors in series (CSTRs). Since the 1940s, continuous emulsion polymerization processes have been developed for a variety of products and with different reactor configurations [328]. This is because these continuous reactor systems have several advantages, such as [329] ... 

When a much larger reactor volume would be needed to go from batch to continuous operation, the required reactor volume can be considerably reduced by using two or more stirred-tank reactors in series. Much of the... 

Other models to characterize residence time distributions are based on fitting the measured distribution to models for a plug flow with axial dispersion or for series of continuously ideally stirred tank reactors in series. For the first model the Peclet number is the characteristic parameter, for the second model the number of ideally stirred tank reactors needed to fit the residence time distribution typifies the distribution. However, these models should be used with care because they assume a standard distribution in residence times. Most distributions in extruders show a distinct scewness, which could lead to erroneous results at very short and very long residence times. The only exception is the co-kneader the high amount of back mixing in this type of machine leads to a nearly perfect normal distribution. 

Liquid monomer is polymerized in continuous stirred tank reactors in a number of processes. The Hypol process, developed by Mitsui Petrochemical, uses a cascaded series of stirred reactors for homopolymerization, followed by fluidized bed gas-phase reactors for copolymerization (274). El Paso (now Himtsman) converted the Rexall liquid monomer process to use high yield catalysts eliminating the sections required for deashing and removal of atactic material (275). Shell (now Basell) developed the LIPP process to produce homopolymers and random copolymers, using their high yield catalysts. 

A flow diagram of the traditional polypropylene suspension ( slurry ) process is shown in Figure 3.13. Propylene, diluent (Cg to saturated hydrocarbons), hydrogen, a catalyst and a cocatalyst are continuously fed to the polymerisation section, which normally consists of one or more stirred tank reactors in series. Polymerisation is carried out at 60 - 80 °C and at pressures below 2 MPa. The polymerised polypropylene forms small powder particles suspended in the diluent. A small amount of atactic polypropylene is formed as a by-product in the polymerisation step and is partly dissolved in the diluent. The slurry is continuously withdrawn from the last reactor after which unreacted propylene is removed from the slurry and recycled to the reactor. 

In a continuous emulsion process, two or more stirred tank reactors in series are used. Separate feed streams are continuously added into each reactor. The reactors are operated at about 68°C. The latex is transferred to a holding tank (residence time of about 4 hr) before being steam-stripped to remove unreacted monomers. In a continuous process, the residence time distribution is generally broad. A large holding tank placed downstream of the reactors provides extra time to the reaction mixture and reduces the molecular-weight distribution. 

Cooking extmders have been studied for the Uquefaction of starch, but the high temperature inactivation of the enzymes in the extmder demands doses 5—10 times higher than under conditions in a jet cooker (69). Eor example, continuous nonpressure cooking of wheat for the production of ethanol is carried out at 85°C in two continuous stirred tank reactors (CSTR) connected in series plug-fiow tube reactors may be included if only one CSTR is used (70). 

Continuous stirred tank reactors (CSTRs) are frequently employed multiply and in series. Reactants are continuously fed to the first vessel they overflow through the others in succession, while being thor-... 

Continuous reactor systems usually consist of stirred tanks connected in series with all the recipe ingredients fed into the first reactor and the product removed from the last reactor. 

A cascade of three continuous stirred-tank reactors arranged in series, is used to carry out an exothermic, first-order chemical reaction. The reactors are jacketed for cooling water, and the flow of water through the cooling jackets is countercurrent to that of the reaction. A variety of control schemes can be employed and are of great importance, since the reactor scheme shows a multiplicity of possible stable operating points. This example is taken from the paper of Mukesh and Rao (1977). 

If three perfectly mixed continuous stirred tank reactors of equal volume were used in series flow instead, what would the required volume be ... 

An autocatalytic reaction is to be carried out in aqueous solution in two identical continuous stirred tank reactors operating in series. The reaction stoichiometry is... 

Consider the reaction system and production requirements discussed in Illustration 10.1. Consider the possibility of using one or more continuous stirred tank reactors operating in series. If each CSTR is to operate at 163 °C and if the feed stream is to consist of pure A entering at 20 °C, determine the reactor volumes and heat transfer requirements for... 

ILLUSTRATION 10.3 ADIABATIC OPERATION OF CONTINUOUS STIRRED TANK REACTORS OPERATING IN SERIES... 

In Section 11.1.3.2 we considered a model of reactor performance in which the actual reactor is simulated by a cascade of equal-sized continuous stirred tank reactors operating in series. We indicated how the residence time distribution function can be used to determine the number of tanks that best model the tracer measurement data. Once this parameter has been determined, the techniques discussed in Section 8.3.2 can be used to determine the effluent conversion level. 

In an ideal continuous stirred tank reactor, CSTR, the composition and temperature are uniform throughout and the condition of the effluent is the same as that of the tank. When a battery of such vessels is employed in series, the concentration profile is step shaped if the abscissa is total residence time or the stage number. 

Several continuous stirred tank reactors are often operated in series or cascade as shown in Fig. 13. In this way, the disadvantages of the relatively low reactant concentration on the one hand, and by-passing on the other, may be partially off-set. As the number of tanks in series increases, the performance of the complete system approaches that of a plug-flow reactor and, in the limit of an infinite number of tanks, becomes equal to it. 

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