Decanters feed configuration

Decanters design drop diameter feed configuration horizontal inlet velocity limit interface control Dew point Diafiltration... 

The first separation step produces essentially the liquid ternary mixture vinyl acetate, water and acetic acid with some dissolved gases. Other light and heavy components are neglected. The RCM analysis indicated as feasible the separation of the heterogeneous azeotrope VAM/water in top followed by quantitative separation of components by decantation. The flowsheet configuration is shown in Figure 10.5. The feed of the column (C-3) collects the ternary mixture from the absorber combined with the water solution from the wash column. The column... 

Several textbooks and reference books (e.g., the third edition of Perry s Handbook, 1950) use this example to illustrate azeotropic distillation. They show the solution sketched in Fig. 11 for a feed whose composition is about 60% -butanol. If we analyze this configuration, we see that it separates the mixture. The same textbooks suggest that for a feed below the azeotropic composition, one should use the same configuration but put the feed into the decanter. The question that occurs immediately is How was this configuration selected Was it a trial-and-error procedure, or is there some way to find it directly ... 

Figure 1 presents the most widely used ASWWTP configurations for combined N and P removal. The A2/0 process presents a sequence of anaerobic reactors (to promote the growth of PAOs) followed by a sequence of anoxic to promote denitrification, and finally aerobic reactors. It has one internal and one external recycle stream. The internal recycle stream conducts a fraction of the nitrified liquor from the last aerobic to the P anoxic compartment, and the external recycle conducts a fraction of the sludge from the underflow of the sedimentation tank to the P compartment. In the UCT process, both recycle streams are feed to the anoxic zone and a second internal recycle stream is present from the anoxic to the anaerobic compartment. The modified UCT process has 2 internal recycles and 1 external one as in the original UCT process but the anoxic zone is divided into 2 zones. The external recycle is directed from the underflow of the decanter to the P anoxic zone. The P internal recycle stream conducts a fraction of the nitrified liquor from the aerobic to the 2 anoxic zone. Finally, the second internal recycle stream pumps a fraction of the mixed liquor from the P anoxic back to the anaerobic compartment. The Bardenpho process configuration has also an external... 

Feed >10% v/v, or contamination present, or ill-behaved, size as coalescence controlled. For vertical decanters, allow a total residence time that depends on density difference and interfacial surface tension. For a typical 0.5-m height of coalescent band (or a decanter of 0.7-m height), use an overflow total flow rate velocity of 1.5 (Ap/0.1)° L/s m, where the density difference is in units of Mg/m to determine the horizontal cross-sectional area. For horizontal configurations, use half of the vertical overflow velocity. Can add parallel plates or high- and low-energy combination coalescer promoters (see size increase, liquid-liquid. Section 16.11.9.2). 

The denser contaminated feed is mixed with the less dense pure solvent in a contactor. The well-mixed stream emerges from this unit and flows into the decanter unit where the two phases are given enough time to fully separate. This is done continuously, so at the entrance of the unit the two liquids are well mixed, but by the end, they are well separated, as shown in the schematic. We will not worry about the internal configuration of this unit. The top layer is the solvent, which leaves the unit with the impurity within it. Some of this solvent is removed from the unit continuously, but the balance is sent back to the contactor for further use. The heavier stream emerges from the decanter unit with a much reduced concentration of impurity. The analysis of this unit calls for a detailed analysis of the suburrits that make it up. 

For practical use, it is commonly preferred a high degree of mixing, as in an ideal CSTR configuration, to properly control the I/O ratio within the whole reactor. In these configurations, catalyst pellets are commonly slurried in the liquid hydrocarbons. To account for a continuous catalyst removal and reactivation, the slurry-riser reactor has been chosen as a suited configuration. In the riser reactors, the feed and the catalyst pellets flow in cocurrent and the solid is Anally separated from the liquid, usually by decanting, after a short contact time. 

Figure 3.48 shows the configuration of this column with a decanter for a reflux drum. Assume that the feed composition is close to the azeotropic composition of IPA -I- H2O mixture. This feed stream may be coming from the distillate of a preconcentrator column with its... 

A simple control stmcture has been developed and demonstrated to be remarkably robust for the separation of the binary heterogeneous azeotropic w-butanol-water system. The process configuration consists of two stripping columns, a decanter, and a single condenser. A tray temperature is controlled in each column. Very large disturbances in feed flowrate and feed composition are effectively handled with product compositions maintamed close to the desired values. 

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