Figures 1 and 2 shows the original Rillieux triple effect evaporator which was installed in a Louisiana sugar factory in 1843. The first effect normally took exhaust steam from the engines driving the cane mill. This exhaust could be supplemented when necessary with steam from the boilers. The crystallising vacuum pans were supplied with vapour off the first body.
In view of the things one sees in many factories to-day it is almost incredible that Rillieux had such an advanced plant working over 100 years ago.
The multiple effect evaporator is dealt with in a number of text books almost all of which try to deal with the analysis by means of formulae. The author believes that this is the wrong way of going about it. By the time the right formula has been found and the equations solved it is just as quick if not quicker to go about it by simple reasoning and simple arithmetic as has been done in this chapter.
The important point about multiple effect evaporation is the proper use of the output vapour for sensible heating, the bleeding off of vapour for sensible heating after it has done several evaporations and the proper heating of the feed by cascade vapour heaters.
