Reflux drum function

At the lop of the tower any intermediate components going out with the gas are condensed, separated, pumped back to the tower, and sprayed down on the top tray. This liquid is called reflux. and the two-phase separator that separates it from the gas is called a reflux tank" or reflux drum. The reflux performs the same function as the cold feed in a cold-feed stabilizer. Cold liquids strip out the intermediate components from the gas as the gas rises. 

The function of the reflux drum in a flooded condenser design is to... 

Finally, the function of the reflux drum is reviewed. Although reflux drums are seldom troublesome, they influence the ability of the colunm to dampen upsets and the extent to which upsets are transferred to downstream units. 

Reflux drums perform one or more of the following functions ... 

A typical reflux drum (Fig. 15.16) consists of four portions, which perform different functions ... 

S( — 1 if all the feed enters tray k, and is zero otherwise, and = 1 if the reflux enters tray k, and is zero otherwise. Additionally, a set of control binary variables 6f are introduced that are associated with each MV-CV pairing and are unity when the pairing exists and zero otherwise. The modelling of the control structure selection is carried our similarly to Narraway and Perkins [15]. These features lead to a mixed-integer dynamic distillation model. The principal differential-algebraic equations (DAEs) for the trays are given below. A full list of nomenclature, values of the parameters, details of the DAEs for the reboiler, condenser, reflux drum and control scheme, cost correlations for the objective function and inequality path constraints, can be found in Bansal et al, [7]. 

As indicated by Figure 9.9, this column has a horizontal condenser and vertical, cylindrical condensate receiver or reflux drum. We will assume that the level controller is of the PI type with set point at midscale of the level transmitter span and that gain 2 auto overrides are employed. Hie level overrides then function as described in the following. 

Reflux Drum Conditions. By definition of the process requirements, it is usually known that the distillate must be either a vapor or a liquid. From this knowledge, the reflux drum conditions are set as a function of the available cooling media. 

Each reactor has its own product cooler, and pairs of reactors and coolers operate alternately to permit cleanout of carbon. The cooled reactor product is fed directly to the prefractionator whose function is to separate the organic chlorides from propylene and hydrogen chloride. Liquid propylene from storage is used as reflux, its flow being regulated by a recorder-controller. This reflux is cooled to about — 40°C, the dew point of the top stream from the prefractionator, by self-refrigeration in a propylene flash drum. 

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