Batch suspension

The batch-suspension process does not compensate for composition drift, whereas constant-composition processes have been designed for emulsion or suspension reactions. It is more difficult to design controUed-composition processes by suspension methods. In one approach (155), the less reactive component is removed continuously from the reaction to keep the unreacted monomer composition constant. This method has been used effectively in VT)C-VC copolymerization, where the slower reacting component is a volatile and can be released during the reaction to maintain constant pressure. In many other cases, no practical way is known for removing the slower reacting component. 

Chain transfer to monomer and to other small molecules leads to lower molecular weight products, but when polymerisation occurs ia the relative absence of monomer and other transfer agents, such as solvents, chain transfer to polymer becomes more important. As a result, toward the end of batch-suspension or batch-emulsion polymerisation reactions, branched polymer chains tend to form. In suspension and emulsion processes where monomer is fed continuously, the products tend to be more branched than when polymerisations are carried out ia the presence of a plentiful supply of monomer. 

Most hybridomas can be grown in batch suspension culture. Recombinant CHO cells can also be adapted for growth in suspension. However,... 

Fig. 1. Schematic of a process for batch suspension culture of mammalian cells, where UF is ultrafiltration and DF is diafiltration.

In a typical batch suspension process (Figure 12-5), styrene is suspended in water by agitation and use of a stabilizer. The polymer forms beads. The bead/water slurry is separated by centrifugation, dried, and blended with additives. 

Classification of Processes and Reactors. Most styrene polymers are produced by batch suspension or continuous mass processes. Some are produced by batch mass processes. Mass in this sense includes bulk polymerization of the polymer... 

Typical Formulations Used for the Batch Suspension Process for Polystyrene... 

Batch stirred tank H SCL/oleum aromatic sulfonation processes, 23 541 Batch stirred tank SO3 sulfonation processes, 23 543 Batch structural models, 20 705 Batch sulfonation, 74 387 Batch suspension cell culture systems, 5 349-352... 

Manufacturing Processes. The three manufacturing processes already mentioned (continuous mass polymerization, batch suspension and emulsion polymerization) continued to compete with each other after 1945. Whereas the third one gradually decreased in importance, the other two were given preference in... 

Alkaloids can be produced in batch suspension cultures, semi-continuous and continuous cultures. Batch suspension cultures multiply the cells in a liquid medium by using a closed system in which only gases are changed. Generally,... 

The batch-suspension process does not compensate for composition drift, whereas constant-composition processes have been designed for emulsion or suspension reactions. It is more difficult to design controlled-composition processes by suspension methods. 

Butler and Spier, 1984), and hybridomas in batch suspension culture... 

Kiparissides, C., Daskalakis, G., Achilias, D. S., Sidiropoulou, E., Dynamic simulation of polyvinylchloride batch suspension polymerisation reactors, Ind. Eng. Chem. Res., 1997, 36, 1253-1267... 

Wieme,)., de Roo, T Marin, G., Heynderickx, G., Simulation of pilot- and industrial-scale vinyl chloride batch suspension polymerization reactors, Ind. Eng. Chem. Res., 2007, 46,1179-1196... 

Batch suspension reactors are, theoretically, the kinetic equivalent of water-cooled mass reactors. The major new problems are stabilization of the viscous polymer drops, prediction of particle size distribution, etc. Particle size distribution was found to be determined early in the polymerization by Hopff et al. (28, 29,40). Church and Shinnar (12) applied turbulence theory to explain the stabilization of suspension polymers by the combined action of protective colloids and turbulent flow forces. Suspension polymerization in a CSTR without coalescence is a prime example of the segregated CSTR treated by Tadmor and Biesenberger (51) and is discussed below. In a series of papers, Goldsmith and Amundson (23) and Luss and Amundson (39) studied the unique control and stability problems which arise from the existence of the two-phase reaction system. 

Description The BP/Lummus styrene polymerization technology for the manufacture of regular and flame-retardant grades of EPS is a one-step batch suspension reaction followed by continuous dewatering, drying and size classification. 

ABB Lummus Global/BP Amoco Polystyrene, expandable Styrene One-step batch suspension process with high reactor productivity 1 1997... 

Typical commercial cell culture systems include batch or fed-batch suspension reactors and perfused immobilized-cell reactors. However, the transient nature of batch culture causes difficulties in studying the effects of external stimuli on growth, metabolism and product formation. Due to metabolite concentration gradients, and the difficulty of obtaining representative cell samples, immobilized-cell reactors are also poorly suited for the analysis of cell growth and metabolism. As a result it is desirable to use well-defined model systems. Continuous-flow suspension reactors allow metabolic parameters to be measured at steady state, after cells have adapted to new (and possibly inhibitory) conditions. Perfusion reactors (with cells immobilized on suspended or stationary supports) extend these benefits to anchorage-dependent cells, and provide model systems for cell responses in vivo. However, while it is instructive to study the behaviour of cells under well-defined conditions, the results obtained must be verified in the culture system selected for commercial production. 

Figure 10.8 Information flow diagram showing interrelationships of batch conservation equations, nucleation and growth kinetic equations, and the resulting CSD in batch suspension crystallizers. (Reproduced by permission of Gordon and Breach Science Publishers S.A. from Wey 1985.)...

Pareilleux and Chaubet (155,156) studied batch suspension cultures of apple cells and Medicago saliva cells, reporting comparable high yield and low maintenance coefficients. Bailey and Nicholson (157) employed in principle the same model structure. However, in order to describe also the changing fresh weight/dry weight ratio, product formation, and cell death and lysis, they extended the model. Two extra variables were added to allow the prediction of the extension phase and a more accurate prediction of the culture death phase caused by shear stress. Another two variables were introduced to describe product formation. In a later paper (158) the authors extended the model further to describe the influence of temperature. With this model an optimal temperature control strategy was predicted. 

Alkaloids can be produced in batch suspension cultures, semi-continuous and continuous cultures. Batch suspension cultures multiply the cells in a liquid medium using a closed system in which only gases are changed. Generally, this method contains the following phases (1) inoculation of cells into the medium, (2) a lag phase in which cells grow slowly, (3) a rapid division phase, and (4) slower division. The duration of Phase 2 is from 0 to 9 days and of Phase 3 is 9 days and replaced by a new medium. In this way, cell growth is continuous, despite cells from different mediums. In continuous cultures, a fresh medium is continuously added. Two open systems are... 

Nigra, H. M., A., A. M. and Giulietti, A. M. (1990) Effect of carbon and nitrogen source on growth and solasodine production in batch suspension cultures of Solamim eleagnifolium Cav. Plant Cell Tissue and Organ Culture. 21, 55-60. 

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