Entrainers separation system

Figure 7.2-11. Spray drier with heat recovery system 1. Spray tower and drying system 2. Air heater 3. Air fan 4. Cyclone dust separator 5. Wet dust separator and entrainment separator 6. Exhaust air fan 7. Pneumatic product conveyer 8. Intermediate product storage 9. Product sieving and packing 10. Wet product pumping system (by courtesy of BMA, TAG-Division). 

However, this so far assumes that the feed to the column is fixed. Even if the overall feed to the separation system is fixed, the feed to each column can be changed by changing the amount of entrainer recycled. Such a trade-off has already been seen in Figure 12.21. As the amount of entrainer recycled is increased, this helps the azeotropic separation. This allows the reflux ratio to be decreased. However, as the entrainer recycle increases, it creates an excessive load on the overall system. The amount of entrainer recycled is therefore an important degree of freedom to be optimized. 

Entrainment Separators. In any process in which the product is volatilized, including both Gas Recycle and Liquid Recycle, ppm or ppb levels of metal catalyst may be entrained in the vapors leaving the separation system. Entrainment separators (Figure 2.9) are often included to recover the metal. Vaporous product effluent from a gas recycle reactor may be sent to a separator where it is passed through a demisting pad to return some aldehyde and condensation product and particularly to prevent potential carryover of catalyst. [6]... 

The still for this system is a simple flash still with a forced circulation reboiler. The saponified, crude glycerine stream is fed into the recirculation pump on the suction side. The recirculation rate is in the range of 40-50 times of the crude glycerine feed rate. The top of the stiU vessel is equipped with a pad style entrainment separator to eliminate carryover. 

Entrainment separators, or catchalls , and mist eliminator pads can be installed where the vapor is removed from the vessel by the vacuum system the recovered product can be returned to the process at an appropriate point. 

First applied for production of distilled water on board ships, flash and multistage flash evaporators have been more recently utilized to evaporate brackish and sea water as well as for process liquids. An aqueous solution is heated and introduced into a chamber which is kept at a pressure lower than the corresponding saturation pressure of the heated feed stream. Upon entering the chamber, a small portion of the heated water will immediately flash into vapor, which is then passed through an entrainment separator to remove any entrained liquid and condense the water vapor. A series of these chambers can be maintained at successively lower pressures with vapor flashing at each stage. Such a system is called a multistageflash evaporator. 

Within the limitations imposed by the determination of trace elements in the total crude oil, when their concentration is essentially confined to a variable portion of the total crude oil, we may conclude that the contents of the trace elements S, V, Cl, Na, Ni, Zn, Co, Mn, Se, Br and As are controlled by maturation processes rather than migration processes, though this may simply reflect maturation of the asphaltene fraction of the crude oils. S, V, Se and Ni account for more than one quarter of the cumulative variance and represent metallo-organic compounds. The factor analyses further demonstrate not only the -efficacy of our separation systems between crude oil and entrained formation water, but show that it is most unlikely that the Fe present in the crude oils originates from corrosion products incorporated during production. Four elements, Fe, Mn, As and Co represent essentially unique factors. Finally, it is clear that considerably more work.is justified on trace elements in crude oils, particularly in relation to their distribution within the various fractions and in relation to interactions between organic and inorganic components. 

Cyclones are low-cost particle collectors that have many potential applications in coal gasification systems however, they have low efficiency for collecting particles smaller than 10 pm but above this size collection efficiency can be at least 90%. Conventional applications for cyclones include use as precleaners, entrainment separators, and for controlling dust emissions from coal grinding and pulverizing (Chapter 6). 

The exhaust air, saturated with water vapor, is first treated in an absorption unit for removal of HjS by routing it through two successive j et scrubbers working with dilute caustic soda solution. Downstream of these, a centrifugal scrubber is installed as an entrainment separator. The sulphide-containing solution rejected from the scrubbers is used to precipitate zinc in the waste water treatment system of the production plant. By products adsorbed on the activated carbon, such as sulphuric acid and elemental sulphur, are removed periodically by water and alkaline extraction. 

In this chapter, design and control of the IPA dehydration process via extractive distillation will be studied. Since, in this distillation system, entrainer selection is an important step before working on the optimal design of the column sequence, we will start by comparing two alternative entrainers for this separation system in the following section. 

---