Liquid flood

Figure 2.2 Schematic representation of an on-column interface. The eluent leaving the HPLC detector enters the valve and in the stand-hy position, leaves it to go to waste. When the valve is switched on, the eluent is pumped through the transfer line into the inlet of the on-column injector. The liquid floods the capillary wall, thus creating a layer that will retain the solutes. Evaporation occurs from the rear pait of the solvent so refocusing the chromatographic hand. At the end of the transfer, the valve is switched off, and the eluent again flows to waste.

Ward and Sommerfeld [130] present an equation based on the curves shown in Figure 9-21C, D and referenced to Eckert [125] and Leva [43] for calculating the gas and liquid flooding rates. There have been numerous other equations targeted for this pmpose, but many are too awkward for easy general use. The proposed equations have been tested by the authors. 

Jet or liquid flooding in one or more sections of the main fractionator... 

If the height of the downcomer, plus the height of the weir, were 24 in, then a downcomer foam height of 24 in would correspond to downcomer flooding. This is sometimes called liquid flood. 

Fig. 4.17. Flow regimes in three-phase fixed-bed reactors, (a) Gas and liquid in co-current downwards flow (trickle-bed operation). (b) Gas and liquid in co-current upwards flow (liquid floods bed), (c) Gas and liquid in countercurrent flow (not often used for catalytic reactors)...

In traditional processing devices, increase in relative velocity is limited by various factors. For example, in column equipment the operating velocity must be smaller than that of liquid-flooding the limitation of relative velocity in common gas-solid or liquid-solid suspensions is the terminal velocity, etc. It seems that other approaches must be found in order to raise the relative velocity between phases to higher levels. 

Flooding in liquid-liquid extraction is similar to vapor-liquid flooding in that the controlling liquid-phase flow rate will cause blockage of the opposite liquid-phase flow if the diameter is too small. However, liquid-phase channeling can happen if the column diameter is too large. Keep-... 

Slightly aerated liquid Aerated liquid Flooding... 

Caprolactone is continuously converted into hexanediol in a fixed bed reactor with the catalyst submerged by the liquid (flooded bed reactor). Hydrogen is charged into the bottom of the reactor in the ratio 10/1 to the caprolactone. It bubbles up through the liquid phase catalyst be mixture. The reaction conditions are 250 C and 280 bar. Backmixing, rather important in this type of reactor, and thermodynamic equilibrium impede a complete conversion. After the recovery of hydrogen in flash drums, the hydrogenated product is distilled in a series of columns where pure 1,6-hexanediol is extracted and unreacted caprolactone returned for recycle (21,22). 

FIGURE 3.2-3 Vapor-liquid flooding correlation. From Fair, Pet./Chem. Eng., 33(10), 45 (September 1961). 

Corrosive. Small splashes cause a local freezing effect. Liquid flooding causes burns affecting the entire exposed area. Ammonia vapor can dissolve in perspiration causing irritation and redness of the skin, depending on the vapor concentration and exposure. 

This is like unsealing a tray s downcomer in a distillation tower. If the bottom edge of the downcomer from a tray is above the top edge of the outlet weir on the tray below, then vapor can blow up through the unsealed downcomer. This will prevent the internal reflux ft om draining down the column. Tower flooding and loss of product separation efficiency will result. This is called liquid flooding or excessive downcomer backup due to loss of the dovmcomer liquid seal. 

The calculated percent of downcomer or liquid flood was 70 percent at 40,000 BSD. 

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