Fourth stage separator

The flue gas passes through a number of small diameter high-efhciency cyclonic elements arranged in parallel and contained with the separator vessel. The UOP design uses an axial flow cyclone. After the catalyst particles are removed, the clean flue gas leaves the separator. A small stream of gas, called the underflow, exits the separator through the bottom of the TSS. In an environmental application, the underflow is diverted to a fourth stage separator (FSS) that is typically a barrier filter. The underflow rate is typically 2-5% of the total flue gas rate and is set by use of a critical flow nozzle. 

Recovered catalyst and blowdown gas (- 3% of the flue gas) exit from the bottom of the separator to an electrostatic precipitator or to a small, fourth-stage cyclone for further concentration of catalyst fines. The flue gas, with 70—90% of the catalyst particles removed, passes from the separator into the power expander. 

The results obtained in the solution of a sample problem are summarized here to illustrate the application of the method. An extractive distillation problem from Oliver (6) was used in which methylcyclo-hexane is separated from toluene by adding phenol. The column contains 11 stages (including the reboiler and condenser) and has a feed of 0.4 moles/unit time of methylcyclohexane and 0.6 moles/unit time of toluene to the fourth stage from the reboiler and 4.848 moles/unit time of phenol to the fourth stage from the condenser. We used the same physical property correlations as Oliver. The activity coefficients were obtained from a multicomponent form of the Van Laar Equation (7). 

A feed stream made up of 40% mole benzene and 60% mole toluene is to be separated into benzene-rich and toluene-rich products using a distillation column. The column has ten equilibrium stages including a partial condenser and a partial reboiler and is operated at 172 kPa. The feed stream, with a flow rate of 100 kmol/h, is at its bubble point at 172 kPa and is placed in the fourth stage from the top. It is required to determine the compositions of the two products at different reflux ratios. Vapor-liquid equilibrium data for the benzene-toluene system are provided in Table 5.1 at 172 kPa. 

We desire to use a distillation column to separate an ethanol-water mixture. The column has a total condenser, a partial reboiler, and a saturated liquid reflux. The feed is a saturated liquid of composition 0.10 mole fraction ethanol and a flow rate of 250 mol/hr. A bottoms mole fraction of 0.005 and a distillate mole fraction of 0.75 ethanol is desired. The external reflux ratio is 2.0. Assuming constant molar overflow, find the flowrates, the number of equilibrium stages, optimum feed plate location, and the liquid and vapor compositions leaving the fourth stage from the top of the column. Pressure is 1 atm. 

The separation will take eight equilibrium stages (the last stage will be the reboiler) and the optimum feed plate will be the fifth from the top. The liquid composition on the fourth stage from the top is 0.28 mole fraction ethanol, and the vapor composition on this stage is 0.56 mole fraction ethanol. 

Another way is the fast removal of carbon dioxide, e.g. by bubbling inert gas through the melt, which favours high supersaturation providing faster crystallization processes than in the first case. The oxide crystals obtained will be smaller, resulting in the formation of fine-size mixtures, which can be used for subsequent thermal treatment. The fourth stage consists of the separation of the oxide crystals from the melts, which can be performed in various ways, which need not be discussed here. 

A fourth stage of membrane-dependent chromatin decondensation, referred to as nuclear swelling (Fig. ID), has also been reported (Collas and Poccia, 1995b). Nuclear swelling is discussed separately in Section VI,A. 

E5. A distillation column is separating a feed that is 30 mol% acetone and 70 mol% ethanol. The column has a partial condenser. Operation is at p = 1 atm The feed flow rate is 1000 kmol/day, the feed is a saturated liquid, and feed is input at the optimum location. We desire a distillate that is 90 mol% acetone and a bottoms that is 10 mol% acetone. Use a boilup ratio of V/B = 1.25. On the fourth stage above the partial reboiler, a vapor sidestream with flow rate S = 200 kmol/day is withdrawn and then condensed to a saturated liquid, which is returned to the column as feed at the optimum location. Assume CMO. Find the mole fraction of vapor side stream y, optimum feed... 

If the solution were removed from Tank 1 and added to Tank 2, which also contained 1 eq of resin in the X ion form, the solution and resin phase would both contain 0.25 eq of Y ion and 0,75 eq of X ion. Repeating the procedure in a third and fourth tank would reduce the solution content of Y ions to 0.125 and 0.0625 eq. respectively. Despite an unfavorable resin preference. using a sufficient number of stages could reduce the concentration of Y ions in solution to any level desired. This analysis simplifies the column technique, but it does provide insights into the process dynamics. Separations are possible despite poor selectivity for the ion being removed. Most industrial applications of ion exchange use fixed-bed column... 

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