Batch stirred tank separator

In a continuous stirred tank separator (CSTS), fluid streams (single or multiphase, with or without solids) enter and leave, and the contents are kept well stirred or well mixed. There is no spatial dependence of species concentrations or any other quantity (such as temperature, pressure, etc.) inside the separator vessel. The species concentrations inside the vessel are at a steady state, sometimes they may change with time however, the outlet stream concentration is different from the inlet stream concentration, and is equal to that inside the CSTS (Figure 6.2.4). Meanwhile, whatever separation mechanism is employed is operative inside the vessel. (A batch stirred tank separator operates such that there is no spatial gradients of concentration, temperature or pressure inside the vessel. Except when the batch is introduced or withdrawn from the vessel, no fluid/solid streams enter or leave the vessel. The conditions inside the vessel may change with time. Generally there is vigorous bulk motion in the vessel.)... 

Batch stirred tank separator in particulate systems... 

The leached solids must be separated from the extract by settling and decantation or by external filters, centrifuges, or thickeners, all of which are treated elsewhere in Sec. 18. The difficulty of solids-extract separation and the fact that a batch stirred tank provides only a single equilibrium stage are its major disadvantages. 

Batch Stirred Tank H2S04/Oleum Aromatic Sulfonation Processes. Low molecular weight aromatic hydrocarbons, such as benzene, toluene, xylene, and cumene, are sulfonated using molar quantities of 98—100% H2S04 in stirred glass-lined reactors. A condenser and Dean-Stark-type separator trap are installed on the reactor to provide for the azeotropic distillation and condensation of aromatic and water from the reaction, for removal of water and for recycling aromatic. Sulfone by-product is removed from the neutralized sulfonate by extraction/washing with aromatic which is recycled. 

Figure 9.2-1. Design of experimental batch-stirred-tank apparatus for synthesis under high pressure 1, reactor 2, separator P, high pressure pump PI, pressure indicator [17].

Section 6.4 covers continuous stirred tank separators. Section 6.4.1 studies equilibrium separation processes most of this section is devoted to crystallization, with additional coverage of liquid extraction. Membrane separation processes/devices are sometimes modeled as CSTRs. Section 6.4.2 touches upon a few of these examples, encountered, for example, in ultrafllUation and gas permeation. There are brief treatments of batch systems that are well-stirred in Sections 6.4.1 and 6.4.2 for both equilibrium based and membrane separation processes. 

The typical bioreactor is a two-phase stirred tank. It is a three-phase stirred tank if the cells are counted as a separate phase, but they are usually lumped with the aqueous phase that contains the microbes, dissolved nutrients, and soluble products. The gas phase supplies oxygen and removes by-product CO2. The most common operating mode is batch with respect to biomass, batch or fed-batch with respect to nutrients, and fed-batch with respect to oxygen. Reactor aeration is discussed in Chapter 11. This present section concentrates on reaction models for the liquid phase. 

The stirred batch reactors are easy to operate and their configurations avoid temperature and concentration gradient (Table 5). These reactors are useful for hydrolysis reactions proceeding very slowly. After the end of the batch reaction, separation of the powdered enzyme support and the product from the reaction mixture can be accomplished by a simple centrifugation and/or filtration. Roffler et al. [114] investigated two-phase biocatalysis and described stirred-tank reactor coupled to a settler for extraction of product with direct solvent addition. This basic experimental setup can lead to a rather stable emulsion that needs a long settling time. 

Continuous Multicomponent Distillation Column 501 Gas Separation by Membrane Permeation 475 Transport of Heavy Metals in Water and Sediment 565 Residence Time Distribution Studies 381 Nitrification in a Fluidised Bed Reactor 547 Conversion of Nitrobenzene to Aniline 329 Non-Ideal Stirred-Tank Reactor 374 Oscillating Tank Reactor Behaviour 290 Oxidation Reaction in an Aerated Tank 250 Classic Streeter-Phelps Oxygen Sag Curves 569 Auto-Refrigerated Reactor 295 Batch Reactor of Luyben 253 Reversible Reaction with Temperature Effects 305 Reversible Reaction with Variable Heat Capacities 299 Reaction with Integrated Extraction of Inhibitory Product 280... 

If product inhibition occurs, either a stirred-tank reactor in batch or a plug-flow reactor should be used. In these two reactors, the product concentration increases with time. Alternatively a reactor with integrated product separation (membrane, solvent, etc.) is preferable. 

There are several possible arrangements tolerating the presence of particles during adsorption of proteins to particulate matrices. Batch adsorption in stirred tanks is performed by contacting adsorbent particles with a cell containing suspension. After protein capture the adsorbent is separated from the broth and the protein of interest can be eluted. This procedure has been described for the isolation of antibiotics [12], the purification of ot-amylase from B. amylo-liquefaciens broth [13], and the isolation of the prothrombin complex from... 

It may also be economical to remove the inhibitory product directly from the ongoing fermentation by extraction, membranes, or sorption. The use of sorption with simultaneous fermentation and separation for succinic acid has not been investigated. Separation has been used to enhance other organic acid fermentations through in situ separation or separation from a recycled side stream. Solid sorbents have been added directly to batch fermentations (18,19). Seevarantnam et al. (20) tested a sorbent in the solvent phase to enhance recovery of lactic acid from free cell batch culture. A sorption column was also used to remove lactate from a recycled side stream in a free-cell continuously stirred tank reactor (21). Continuous sorption for in situ separation in a biparticle fermentor was successful in enhancing the production of lactic acid (16,22). Recovery in this system was tested with hot water (16). 

Chain Reaction with Termination. More work has been done on this mechanism, using free radical polymerization as the principle example. As shown in Table IV, batch polymerization has received far more interest within this area than the simpler case of continuous polymerization in a stirred tank, presumably because of commercial laboratory practice. The limited work on tubular reactors is not shown and will be discussed separately later. 

Immobilized enzymes can be used in one of two basic types of reactor systems. The first is the stirred tank reactor where the immobilized enzyme is stirred with the substrate solution. This is a batch system and, after the reaction is complete, the immobilized enzyme is separated from the product. The other system employs continuous flow columns in which the substrate flows through the immobilized enzyme contained in a column or similar device. A simplified flow diagram of such a system is given in Figure 10-23. 

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