Once-through thermosyphon reboiler difference

Figure 5.2 shows a once-through thermosyphon reboiler. The driving force to promote flow through this reboiler is the density difference between the reboiler feed line and the froth filled reboiler return line. 

Figure 5.3 shows a once-through thermosyphon reboiler with a vertical baffle. This looks quite a bit different from Fig. 5.2, but processwise, it is the same. Note that the reboiler return liquid goes only to the hot side of the tower bottoms. Putting the reboiler return liquid to the colder side of the tower bottoms represents poor design practice. 

This last statement requires some clarification. But to understand our explanation, an understanding of the important differences between a once-through thermosyphon reboiler, and a circulating thermosyphon reboiler, is critical. Figure 5.4 shows a circulating reboiler. In this reboiler... 

Figure 5.6 shows a once-through forced-circulation reboiler. Such a reboiler differs from a thermosyphon reboiler in that it has a pump to force circulation, rather than rely on natural or thermosyphon circulation. This seems rather wasteful—and it is. 

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See also in sourсe #XX -- [ , , ]

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