Condenser overhead

A stream divider simply splits a stream into two or more streams of the same composition. Consider Fig. 13-21, which pictures the division of the condensed overhead liquid into distillate D and... 

Because steam is injected into the operation in various places in Figure 11.17, the steam is condensed overhead and is separated in a decanter from the condensing hydrocarbons and the hydrocarbons that do not condense. 

Ester manufacture is a relatively simple process in which the alcohol and an acid are heated together in the presence of a sulfuric acid catalyst, and the reaction is driven to completion by removing the products as formed (usually by distillation) and employing an excess of one of the reagents. In the case of ethyl acetate, esterification takes place in a column that takes a ternary azeotrope. Alcohol can be added to the condensed overhead liquid to wash out the alcohol, which is then purified by distillation and returned to the column to react. 

Figure 9.5 illustrates the sulfuric acid concentrations that lead to the production of higher concentrations of nitric acid. At a concentration of 67 weight % H2SO4, the azeotropic point has vanished, and 99 weight % nitric acid can be distilled. The nitric acid is the lighter phase and is extracted as vapor. These vapors are condensed overhead and a portion of the nitric acid is returned to the distillation column as reflux. The sulfuric acid and water go with the bottom liquid phase and are concentrated for reuse in the process104,220. 

The feed to a hydrofluoric acid alkylation unit is desiccant dried and then sent to the combined reactor settler (Figure 2.8). The reaction occurs at 90 to 100°F (32 to 38°C), at 250 psia (1,725 kPa), and in the presence of 90% hydrofluoric acid. The effluent from the combined reactor settler is fed to the main fractionator. The hydrofluoric acid goes overhead with the light ends and is condensed and collected in the accumulator. Part of the condensed overhead fluid is recycled from the feed to the combined reactor settler, part is used for reflux to the main fractionator, and the remainder is fed to the hydrofluoric acid stripper. The overhead of the stripper is returned to the main fractionator overhead condenser. The bottom product of the stripper is caustic washed to remove all traces of hydrofluoric acid. The bottom product of the main fractionator is often fed to a debutanizer fractionator column. 

Function Condense overhead vapors from methanol fractionation column ... 

Minimum Stages A column operating at total reflux is represented in Fig. 13-28(1. Enough material has been charged to the column to fill the reboiler, the trays, and the overhead condensate drum to their working levels. The column is then operated with no feed and with all the condensed overhead stream returned as reflux (Lf/+i = Vf/ and D = 0). Also all the liquid reaching the reboiler is... 

In addition, we have assumed that the pressure of the reflux divider is the same as the pressure of the condenser, the heat loss from the reflux divider is zero, and the reflux temperature is the boiling point of the condensed overhead vapor. 

Donald F. Othmer while at Eastman Kodak during the 1920 s experimented using salts to concentrate acetic acid (14). He also developed an industrial process for distilling acetone from its azeotrope with methanol by passing a concentrated calcium chloride brine down the rectification column (15). Pure acetone was condensed overhead, and acetone-free methanol was recovered in a separate still from the brine which was then recycled. The improved Othmer recirculation still (16) has been the apparatus generally favored by investigators who have studied the effects of salts on vapor-liquid equilibrium. 

The second way in which the program is operated is to calculate rigorously with the subprogram ADPLLE. These calculations are reliable for either two- or three-phase equilibria. The azeotropic distillation columns and the liquid-liquid equilibria for the condensed overhead in the accumulator is calculated with this program. 

Distillation columns The simulator column models include not just the column itself, but also the reboiler, condenser, overhead receiver drum, and reflux pump (but not bottoms pump). ICARUS has 10 possible configurations to which a column can be mapped. Alternatively, the column can be mapped to a packed or trayed tower, and the ancillary items can be created as separate Icarus project components. 

Fig. 24 shows a vapor permeation unit installed to remove methanol from the top of a column, treating the boil-off from a transesterification reactor. The column is operated to condense overhead product close to the azeotropic point. Condensed liquid is refluxed through the column. Net overhead vapor is passed through the vapor permeation unit, which is sized to... 

The foregoing eqontions apply to simple takeover batch distillation, with no reflux. If a column is installed abuve the stillpot and provision is made to return a portion of the condensed overhead vapor to the column as reflux, it is possible to obtain a much better separation. As an extreme case, near-total reflux is used to get the best possible separation, without regard to the length of time required for die revalorization of the reflux. Uader such a condition, the Fenske relationship [Eq. (5.3-28)] may be ased to relate the siillpot vapor composition to that of the vapor passing over to the condenser ... 

The concentrated withdrawn polymer slurry is flashed to separate the powder from the diluent and unreacted monomers. The polymer flows from the bottom of the flash tank, with the condensed overheads... 

Fixed auxiliary equipment for general purpose stirred vessels (sized accordingly) condensers, decanters, receivers, weighing tanks, solids charging devices, sampling devices, pumps and piping, connectivity to the tank farm and to pollution abatement equipment, connectivity among each other, vacuum sources, vent trim condensers, overhead catch tanks, in-line filters, flow splitters, etc. 

Sidestream Vapor to condenser Overhead product, light ends Reflux... 

The shifting of A] A2 is of practical use in separating water rich isopropanol/water mixtures (Fig. 2-31 b). A feed/"is almost completely separated into water flow rate JV leaving column DCl and a isopropanol flow rate P leaving column DC2. Both columns are operated at ambient pressure. The overhead products AT, and JC2 are practically of azeotropic composition (point Aj, Fig. 2-31 a). In the condenser C, most of the condensed overhead products form the reflux / , or / 2, to the columns DCl or DC2, respectively. The remainder is then separated into a water rich fraction >i and an alcohol rich fraction >2 in the diffusion distillation unit DA (Fig. 2-31 c shows the diffusion separation unit). Some of the overhead product fluxes Kj and K2 are heating the unit while water is used for cooling. 

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