Horizontal decanters

Figure 3.5 Clarifying decanter (horizontal scroll centrifuge). Source Courtesy of Westfalia Separator Ltd.

Gravity Settlers Decanters These are tanks in which a liqmd-liquid dispersion is continuously settled and coalesced and from wriich the settled liquids are continuously withdrawn. They can be either horizontal or vertical. Figure 15-24 shows some typical horizontal decanters. For an uninstrumented decanter the height of the heavy-phase-liquid leg above the interface is balanced against the height of the hght-hquid phase above the interface, Eq. 15-50. 

The adsorbers are usually built of steel, and may be lagged or left unlagged the horizontal type is shown in Figure 28. The vapor-laden air is fed by the blower into one adsorber which contains a bed of 6- to 8-mesh activated carbon granules 12 to 30 inches thick. The air velocity through the bed is 40 to 90 feet per minute. The carbon particles retain the vapor only the denuded air reaches the exit, and then the exhaust line. The adsorption is allowed to continue until the carbon is saturated, when the vapor-laden air is diverted to the second adsorber, while the first adsorber receives low-pressure steam fed in below the carbon bed. The vapor is reformed and carried out by the steam. The two are condensed and if the solvent is not miscible with water, it may be decanted continuously while the water is run off similarly. After a period which may be approximately 30 or 60 minutes, all the vapor has been removed, the adsorbing power of the charcoal has been restored, and the adsorber is ready to function again, while adsorber No. 2 is steamed in turn. 

Horizontal Gravity Settlers or Decanters, Liquid/Liquid... 

Z), = hea ) phase outlet dimension from bottom of horizontal decanter... 

To begin, there is a dispersion band through w hich the phases must separate. Good practice [32] normally keeps the vertical height of the dispersed phase, Hd < 10% of decanter height (normally a horizontal vessel), and ... 

V = Settling velocity for hindered uniform spherical particle, ft/s or m/s Wi= Width of rectangular cone inlet duct, ft Z], = Heavy phase outlet dimensions of decanter measured from horizontal bottom, shotvn on Figure 4-12... 

Many processes require the separation of immiscible liquid/liquid streams that is, water/hydrocarbon. The settling unit must be of sufficient height (diameter) and length to prevent entrainment of the aqueous phase into the hydrocarbon and vice versa. Horizontal units are usually best for setding and possibly vented units for decantation (but not always). 

Gravity decanter, illustration, 243, 244 Happel/Jordan method, 241 Horizontal gravity, 239 Lamella classifiers, 239 Settler vessel, illustration, 240 Time planning and scheduling, process design, 36... 

For a horizontal, cylindrical, decanter vessel, the interfacial area will depend on the position of the interface. 

Stacks of horizontal, parallel, plates are used in some proprietary decanter designs to increase the interfacial area per unit volume and to reduce turbulence. They, in effect, convert the decanter volume into several smaller separators connected in parallel. 

Gravity separators can take many shapes and arrangement, depending in part on the characteristics of the waste. Typical design configurations include horizontal cylindrical decanters, vertical cylindrical decanters, and cone-bottomed settlers. 

Figure 8.1b shows a simple gravity settler or decanter for removing a dispersed liquid phase from another liquid phase. The horizontal velocity must be low enough to allow the low-density droplets to rise from the bottom of... 

The water can be assumed to be dispersed in the hydrocarbon. Estimate the size of decanter required to separate the mixture in a horizontal drum with a length to diameter ratio of 3 to 1 and an interface across the center of the drum. 

Figure 5.13. Large-scale oxo plant using the water-soluble Ruhrchemie/Rhone-Poulenc catalyst [HRh(COXTPPTS)3]. Note the horizontal decanter in front of the reactor...

The sample should be sent as rapidly as possible to the laboratory, and when the analysis is not to be carried out immediately the bottles are stored horizontally and in a cool, but not excessively cold, place. Turbid samples are either left for some time and then decanted or filtered prior to analysis, the residue being examined separately if necessary. The determination of sulphur dioxide should be made before filtration and as soon as the bottle is opened. 

Decanting losses were much higher than anticipated. In an attempt to minimize losses, the chemical composition of the precipitation batches was varied to increase the oxalate/aluminum ratio. These variables had little effect on product losses because the solubility losses were very low (<15% of the actual loss). Apparently, Am-Cm oxalate solids are being suspended prior to and during decanting (perhaps due to the decay heat of Cm) and a portion of the suspended precipitate was decanted. A new decant jet, which had a plate welded across the bottom and holes drilled around the pipe above the plate to provide horizontal rather than vertical suction, was fabricated and installed after the fifth batch. Losses, however, remain unchanged. 

Two major types of centrifugal separators are used in press-type oil/fat extractions and wet rendering horizontal decanters and vertical stacked conical disk centrifuges. A drawing of a... 

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