Heating and Cooling Techniques

Different technical solutions are used in the temperature control of industrial reactors. The heat carriers mentioned in Section 9.2.f may be used by different technical means the direct way whereby the heat carrier is directly mixed with the reaction mass, internal or external coils, jacket, simple circuits, and indirect systems with a double circulating system. These techniques with their advantages and drawbacks, in terms or process safety, are reviewed in the following sections. 

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Figure 3. The regions of pressure and temperature accessible by joining static compression methods to heating and cooling techniques are compared to the Earth geotherm and to Jupiter and Uranus isentropes.

In order to control the reaction course and so avoid a runaway incident, it is essential to understand how heating-cooling systems of reactors work and what their performance is. These topics are reviewed in this chapter, where different heating and cooling systems are reviewed from the particular implications on process safety. In the first section, the different heating and cooling techniques... 

Guijt et al. [7] suggested an on-chip heating and cooling technique by using endothermic or... 

Guijt et al. [7] suggested an on-chip heating and cooling technique by using endothermic or exothermic processes in a microchannel to cool or heat solutions within an adjacent sample channel. Chemical or physical processes of solutions in a channel such as evaporation of acetone and exothermic dissolution of H2O4 in water are used to cool and heat an adjacent channel (Fig. 3). 

Most polymer processing methods involve heating and cooling of the polymer melt. So far the effect of the surroundings on the melt has been assumed to be small and experience in the situations analysed has proved this to be a reasonable assumption. However, in most polymer flow studies it is preferable to consider the effect of heat transfer between the melt and its surroundings. It is not proposed to do a detailed analysis of heat transfer techniques here, since these are dealt with in many standard texts on this subject. Instead some simple methods which may be used for heat flow calculations involving plastics are demonstrated. 

Bajugam and Flitsch [217] have described the synthesis of glycosylamines from mono-, di-, and trisaccharides by direct microwave-assisted Kochetkov amination (Scheme 6.110). The reaction was found to be effective with just a fivefold excess (w/w) of ammonium carbonate with respect to the sugar, as compared to the 40-or 50-fold excess needed under thermal conditions. All transformations were completed within 90 min in dimethyl sulfoxide as solvent, maintaining the vessel temperature at an apparent 40 °C using the heating-while-cooling technique (see Section 2.5.3). 

There are two techniques for rejoining separated liquid ends heating and cooling. The option chosen will depend on the location of the break, as well as on the existence and location of contraction or expansion chambers. 

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