Feed Control by Accumulation

The condition for the practical implementation of such a feed control is the availability of a computer controlled feed system and of an on-line measurement of the accumulation. The later condition can be achieved either by an on-line measurement of the reactant concentration, using analytical methods or indirectly, by using a heat balance of the reactor. The amount of reactant fed to the reactor corresponds to a certain energy of reaction and can be compared to the heat removed from the reaction mass by the heat exchange system. For such a measurement, the required data are the mass flow rate of the cooling medium, its inlet temperature, and its outlet temperature. The feed profile can also be simplified into three constant feed rates, which approximate the ideal profile. This kind of semi-batch process shortens the time-cycle of the process and maintains safe conditions during the whole process time. This procedure was shown to work with different reaction schemes [16, 19, 20], as long as the fed compound B does not enter parallel reactions. 

A Grignard reagent is to be prepared at industrial scale at a temperature of 40 °C in THF as a solvent (Th = 65 °C). The reaction scheme is 

In a laboratory experiment in a reaction calorimeter, a bromo-compound was added at a constant feed rate over 1.5 hours. The data obtained during this experiment are summarized as follows  

At industrial scale, the charge should be 4000 kg, the heat exchange area of  

May the boiling point be reached in the case of cooling failure, if the feed is immediately stopped  

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