Reactor schemes

A first-order, exothermic reaction occurs within a continuous stirred-tank reactor, equipped with jacket cooling, where the kinetics and reactor schemes are... 

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). 

Diblock OBCs from continuous CCTP are different from either of the previous two families of copolymers. The continuous process produces blocks lengths with MJMn approaching 2.0. However, the CCTP process in a series of reactors results in a narrower overall distribution, with M JMn approaching 1.5 in the case of a symmetric diblock. The number of blocks per chain is determined by the number of reactors connected in series. Finally, the dual reactor scheme ensures precise block junctions with homogeneous copolymer compositions. 

Figure 6.21 (a) The best multiple reactor scheme, (b) The best scheme when unconverted reactant can be separated and recycled. 

Determine which setup, plug flow, mixed flow, or any two-reactor combination gives minimum r for 90% conversion of a feed consisting of Cao 100. Also find this r minimum. If a two-reactor scheme is found to be optimum, give between stages and r for each stage. 

For the set of elementary reactions of Problem 10.6, with a feed of AO = 1 mol/liter and u = 100 liters/min we now wish to maximize the production rate of intermediate S (not the fractional yield) in a reactor arrangement of your choice. Sketch your chosen reactor scheme and determine Cs ax obtainable. 

The second patent by Upjohn describes an improved route, obviating the use of the sealed tube reactor (Scheme 6). Therefore, 6-amino-4-chloro-2-imino-2H-pyrimidin-l-ol (28) was prepared from the oxidation of 4-chloro-pynmidine-2,6-diamine (27). The crude product was extracted with boiling acetonitrile to give pure 28 in 44.7% yield. Refluxing 28 with excess of piperidine for 1.5 h then afforded minoxidil (3) after extraction with boiling acetonitrile. 

Bose et alm have demonstrated the synthesis of aspirin from salicylic acid and acetic anhydride using commercial microwave reactors (Scheme 9.6). Without optimising the conditions, high purity aspirin was obtained in greater than 80% yield (500-800 g scale). 

More recently Peng and Song reported the rapid synthesis of a library of hydrazides in a MW-US combined reactor (Scheme 9.20)139. Unlike the aforementioned system that employed decalin as an energy transfer medium for the ultrasound irradiation, in their modified domestic oven, the horn was immersed directly into the reaction mixture. 

Scott, T. C., C. G. Hill, and C. H. Amundson, "Determination of the Steady-state Behavior of Immobilized beta-Galactosidase Utilizing an Integral Reactor Scheme," Biotechnol. Bioeng. Symp. 15 (1985) 431 - 445. 

In 2005, very similar reactions were shown to proceed smoothly in continuous flow reactors (Scheme 45). The yield of couplings with aryl bromides and iodides were overall high, although the authors noted that it was not clear exactly how long a sample was irradiated due to uncertainties regarding the focus of the irradiation over the capillary column [119]. 

The batch reactor, one of the five primary reactor configurations, is the oldest reactor scheme. 

Although, at the end of the twentieth century, the accident at Chernobyl has made the use of fission reactors (eventually breeders) politically unacceptable, it must be recalled that our society can be run on electricity from nuclear reactors, with hydrogen as the storage medium and fuel for transportation. Fail-safe reactor schemes have been described in the literature. The eventual choice between nuclear energy and renewables will be one of cost. 

A simple tandem reverse-flow reactor scheme has been proposed for this purpose [11] (Fig. 7.5). By condensing the sulfur formed in the reactor outlet and reheating the residual anhydrous inert gas stream, one obtains a thermally efficient integration of the elutive adsorbent regeneration into the reactor operation. The arrangement depicted represents an adsorptive equivalent to the reverse-flow reactor with removal of a hot side-stream [6]. 

N-propionyloxazolidinone and the subsequent diastereoselective alkylation with benzyl bromide at —100 °C. The observed diastereomeric ratio of 91 9 was superior to that of 85 15 observed in a batch reactor (Scheme 4.9) [11,13],... 

In the once-through studies reported in the literature, a downflow reactor scheme was used for catalytic hydrocracking (9) in contrast to an upflow reactor scheme used in this study. It has been reported in the literature that an upflow reactor scheme is superior to the usual trickle-bed operation for residual feedstocks (18,19). Desulfurization, denitrogena-tion, and demetallization conversions were better in an upflow reactor. 

Figure 2. AJkylator reactor scheme (single liquid phase)...

The use of alkali metal oxide catalysts for aldol condensation reactions has been examined for the production of 2-ethylhexenal from butanal [34]. When coupled to a hydrogenation catalyst the system can produce the plasticizer alcohol 2-ethyl-hexanol directly. When isobutyraldehyde was used as the feed to a silica-supported sodium oxide catalyst, no products were formed but a significant amount of carbon was deposited on the catalyst and in the reactor (Scheme 21.2). 

Unfortunately, if the reaction rate is not first-order, the RTD cannot be used so directly to obtain the conversion. To illustrate why this is so, consider the two reactor schemes shown in Figure 8.3.1. 

In case methanol is used as an intermediate fuel (e.g. in mobile fuel cells), the cost of methanol production is of interest. Produced from fossil fuels, notably natural gas, at a price of 3 US GJ, reforming or series reactor schemes lead to a methanol production cost estimated around 5.5 US GJ (Lange, 1997). Advanced micro-structured string-reactors for this concept are under development (Homy et ah, 2004). 

Ordinarily, laboratory data are used to formulate a rate law, and then the reaction rate-conversion functional dependence is determined using the rate law. Preceding sections show that with the reaction rate-conversion relationship, different reactor schemes can readily be sized. In Chapter 3 we show how we obtain this rel onship between reaction rate and conversion from rate law and reaction stoichiometry. 

We will use this value of AO together with either Table 2-2 or Figure 2-1 to size a number of reactor schemes in Examples 2-2 through 2-5,... 

We will now use the value of FiS,o calculated in Example 2-1 together with Figure 2-1 to size each of the reactors for the three reactor schemes. The first scheme to be considered is the two CSTRs in series shown in Figure 2-3, For the first reactor in which the rate of disappearance of A is -jai at conversion Xi, the volume necessary to achieve the conversion Xj is... 

In a highly efficient and costly reactor scheme in which very little of undesired product U is formed in the reactor, the cost of the separation process could be quite low. On the other band, even if a reactor scheme is inexpensive and inefficient, resulting in the formation of substantial amounts of U, ffie cost... 

I m not talidng about fun you can have at an amusement park, but CRE fun. Now that we have an understanding on how to solve for the exit concentrations of multiple reactions in a CSTR and how to plot the species concentration down the length of a PER or PER, we can address one of the most important and fun areas of chemical reaction engineering. This area, discussed in Section 6.1, is learning how to maximize the desired product and minimize the undesired product. It is this area that can make or break a chemical process financially. It is also an area that requires creativity in designing the reactor schemes and feed conditions that will maximize profits. Here you can mix and match reactors, feed steams, and side streams as well as vary the ratios of feed concentration in order to maximize or minimize the selectivity of a particular species. Problems of this type are what I call digital-age problems - because... 

Selectivity, reactor schemes, and staging for multiple reactions, together with evaluation of the corresponding design equations, are presented in... 

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