Batch laboratory reactors

Gas-solid (reactant) Thermogravimetric apparatus Single-pellet reactor 

Gas-solid (catalytic) Differential reactor Integral reactor Mixed (Carberry) reactor Microreactor Fluid-bed reactor Single-pellet reactor 

Gas-liquid Wetted disk reactor Danckwerts cell Levenspiel-Godfrey reactor 

Mixed microreactor Small batch reactor Autoclave 

Stirred batch reactor Rotating disc contactor (RDC) 

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The chemical kinetics are the same for any type of reactor. Most of the kinetic information used to design CSTRs is obtained from batch laboratory reactors ... 

Computational fluid mechanics has had some notable successes in duplicating experimental results for turbulent reactors, both tubes and tanks. As one example, one simulation closely agreed with experiments for the yield of a Bourne reaction in a fed-batch laboratory reactor that was stirred by a half-moon agitator ... 

A pilot plant scale, tubular (annular configuration) photoreactor for the direct photolysis of 2,4-D was modeled (Martin etal, 1997). A tubular germicidal lamp was placed at the reactor centerline. This reactor can be used to test, with a very different reactor geometry, the kinetic expression previously developed in the cylindrical, batch laboratory reactor irradiated from its bottom and to validate the annular reactor modeling for the 2,4-D photolysis. Note that the radiation distribution and consequently the field of reaction rates in one and the other system are very different. 

THE PROBLEM A batch laboratory reactor with an electrolyte volume of 700 cm and an electrode area of 30 cm is used to deposit a divalent metal from an aqueous solution in a potentiostatic mode. Initial concentration of the metal is O.lkmol/m. The reactor mass transfer coefficient has been measured as 3.3 x 10" m/s. Hydrogen evolution occurs as a parallel reaction according to the equation % = H p [ — ], where kn = 1.30 X 10" A/m and = 12 If the metal deposition is operated at its limiting current density at an electrode potential of —0.9 V (SCE), determine how conversion, total current density, and current efficiency vary with time, in a potentiostatic mode. What will be the current efficiency at the final... 

Figure 7.2 Alternative configurations of batch laboratory reactors to obtain kinetic data, mainly from homogeneous mixtures, (a) Round-bottomed flask in a heating mantle, (b) ampules in a thermostat, (c) small bench-scale reactor in a thermostat, (d) boat containing liquid reactant in a furnace with or without a flowing gaseous reactant, (e) reactor with provision for measuring evolving gas, (f) mixed microreactor, (g) calorimetric reactor, and (h) output from calorimetric reactor. 1, Removable lid 2, thermal buffer zone 3, heating elements 4, thermopiles 5, experimental area 6, calorimetric block 7, insulation layers and 8, cooling circuit.

Quality control tests or improvement of existing processes. Raw materials from various sources can be used in the manufacture of fine chemicals and pharmaceuticals. The raw materials can contain different impurities at various concentrations. Therefore, before the raw material is purchased and used in a full-scale batch its quality should be tested in a small-scale reactor. Existing full-scale procedures are subject to continuous modifications for troubleshooting and for improving process performance. Laboratory reactors used for tests of these two kinds are usually down-scaled reactors or reactors being a part of the full scale-reactor. 

FIGURE 15.1 Schematic diagram of a laboratory-scale, sequencing batch (bio) reactor (SBR). 

Company D is a large pharmaceutical manufacturer with worldwide operations. CSB staff visited a pilot-plant facility and thermal hazards laboratory. Pilot-plant operations included the use of several batch chemical reactors. Like Company A, this company also frequently changes chemicals handled and manufacturing techniques. 

Three ideal reactors—the batch reactor, the plug-flow reactor and the perfectly stirred reactor—are mathematical approximations to corresponding laboratory reactors that are used regularly to study chemical kinetics (Section 13.3.2). The batch reactor (or static reactor) is particularly useful to characterize explosion limits [241] and kinetic behavior at temperatures below 1000 K (e.g., [304,351]), while stirred reactors (e.g., [151,249,296, 367,397]) and flow reactors (e.g., [233,442]) have proved highly valuable in the study of chemical kinetics at higher temperatures. 

Today s laboratory-scale batch microwave reactors generally offer a maximum batch size of 1 L reaction volume, in most cases divided into several smaller reaction vessels (multivessel rotor systems). According to the definition given at the beginning, this would not exactly match the one vessel ... 

Figure 4-19. Stirred batch reactor. (Source V. W. Weekman, Laboratory Reactors and Their Limitations, AlChEJ, Vol. 20, p. 833, 1974. Used with permission of the AlChEJ.)...

Various laboratory reactors have been described in the literature [3, 11-13]. The most simple one is the packed bed tubular reactor where an amount of catalyst is held between plugs of quartz wool or wire mesh screens which the reactants pass through, preferably in plug flow . For low conversions this reactor is operated in the differential mode, for high conversions over the catalyst bed in the integral mode. By recirculation of the reactor exit flow one can approach a well mixed reactor system, the continuous flow stirred tank reactor (CSTR). This can be done either externally or internally [11, 12]. Without inlet and outlet feed, this reactor becomes a batch reactor, where the composition changes as a function of time (transient operation), in contrast with the steady state operation of the continuous flow reactors. 

There are four ideal reactors the batch reactor (real counterpart stirred tank reactor), semibatch reactor,1 continuous stirred tank reactor (CSTR), and the plug flow tubular reactor (PFTR) (real counterpart tube reactor). For production applications, there are also numerous other reactors [7-9], An overview of typical and advanced laboratory reactors was given by Kapteijn and Moulijn [6],... 

As an example, the experimental data using stirred semi-batch laboratory-scale reactor [7] was obtained from the catalytic degradation of various plastics over spent FCC... 

Laboratory pyrolysis of HDPE was first carried out using the batch mode reactor (Eigure 13.2). After flushing the system with an inert gas, the reactor was lowered into the floor furnace. The furnace was heated from room temperature to the pyrolysis temperature in 15-20 min and held at that temperature for 1 h before cooling back to room temperature. There was complete conversion of the HDPE in all runs and the reactor was clean at the end of the run. Several runs were carried out to optimize the temperature and pressure conditions. 

Chromatographic batch reactors are employed to prepare instable reagents on the laboratory scale (Coca et al., 1993) and for the production of fine chemicals. These applications include the racemic resolution of amino acid esters (Kalbe et al., 1989), acid-catalyzed sucrose inversion (Lauer, 1980), production of dextran (Zafar and Barker, 1988) and saccharification of starch to maltose (Sarmidi and Barker, 1993a). Sardin et al. (1993) employed batch chromatographic reactors for different esterification reactions such as the esterification of acetic acid with ethanol and the transesterification of methylacetate. Falk and Seidel-Morgenstern (2002) have investigated the hydrolysis of methyl formate. 

Fig. 4. Operational stability of penicillin G amidase immobilized on epoxy carrier. Batch cycles were run in a 1.5-1 laboratory reactor at 10% penicillin G, 6 kU L 36 °C. pH was maintained at 8.0 by the addition of 2 N NH3. Initial splitting time was 65 min. The initial activity (relative base consumption per min at the beginning of each batch conversion) is plotted against the cycle number. PGA was immobilized on polymethacrylate with an epoxy density >2000 pmol g" (squares) or of 600 pmol g" (triangles)...

Laboratory and field testing determined the effectiveness of a new decontamination process for soils containing 2,4-D/2,4,5-T and traces of dioxin. The process employs three primary operations - thermal desorption to volatilize the contaminants, condensation and absorption of the contaminants in a solvent, and photochemical decomposition of the contaminants. Bench-scale experiments established the relationship between desorption conditions (time and temperature) and treatment efficiency. Laboratory tests using a batch photochemical reactor defined the kinetics of 2,3,7,8-TCDD disappearance. A pilot-scale system was assembled to process up to 100 pounds per hour of soil. Tests were conducted at two sites to evaluate treatment performance and develop scale-up information. Soil was successfully decontaminated to less than 1 ng/g... 

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