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Chapter: 14 -Problem: 6 >> What are the three mechanisms for mass transfer through a porous membrane? Which are the best mechanisms for making a separation? Why?
Answer Preview: a. Diffusion b. Osmosis c. Evaporation d. Simple filtration Simpl…

, Chapter: 13 -Problem: 31 >> One hundred kmol of 45 mol% acetone, 30 mol% chloroform, and 25 mol% benzene is charged at 101.3 kPa to a batch rectifier consisting of a still-pot, a column containing the equivalent of 10 equilibrium stages, and a total condenser. After establishing a totalreflux condition, the column will begin a sequence of two operating steps, each at a distillate flow rate of 2 kmol/h and a reflux ratio of 1
Answer Preview: Calculation. The mole-fraction composition and amoun…

, Chapter: 15 -Problem: 17 >> For fixed-bed adsorption, what is the difference between superficial velocity, interstitial velocity, and concentration wave velocity? Which is the largest and which is the smallest?
Answer Preview: First, lets take a look at what these numbers and physics concepts actually mean. Superficial veloci…

, Chapter: 15 -Problem: 41 >> An aqueous solution, buffered to a pH of 3.4 by sodium citrate and containing 20 mol/m3 each of glutamic acid, glycine, and valine, is separated in a chromatographic column packed with Dowex 50W-X8 in the sodium form to a depth of 470 mm. The resin is 0.07 mm in diameter and packs to a bed void fraction of 0.374. Equilibrium data follow a linear law, as in Example 15.15, with the following dimensi
Answer Preview: The first step is to calculate the pulse duration needed t…

, Chapter: 15 -Problem: 23 >> Compare the advantages and disadvantages of chromatographic purification of proteins bovine serum albumin, cytochrome C, and ovalbumin by size-exclusion, reversed-phase, hydrophobic-interaction, ion-exchange, affinity chromatography, countercurrent contacting, and stacked-membrane chromatography. Consider resolution, speed, capacity, throughput, recovery, activity, and final purity.
Answer Preview: Solution; Size exclusion chromatography Advantages: The separation mechani…

, Chapter: 15 -Problem: 18 >> What is the difference between a true-moving-bed (TMB) system and a simulated-moving-bed (SMB) system?
Answer Preview: Moving: The process principles of a true moving bed are shown in Figure 1. The solid phase i…

, Chapter: 14 -Problem: 7 >> What is the mechanism for mass transfer through a dense (nonporous) membrane? Why is it called solution-diffusion? Does this mechanism work if the polymer is completely crystalline? Explain.
Answer Preview: Solutions penetrate through a membrane based on the concentration gradient. Diffusion is an alternat…

, Chapter: 14 -Problem: 5 >> For a membrane separation, is it usually possible to achieve both a high permeability and a large separation factor?
Answer Preview: Yes, you can usually achieve both a large separation factor and a high permeability. This all depend…

, Chapter: 14 -Problem: 4 >> A hollow-fiber module has 4,000 ft2 of membrane surface area based on the size of the fibers, which are 42 mm i.d. x 85 mm o.d. x1.2 m long each. Determine the: (a) Number of hollow fibers in the module; (b) Diameter of the module, assuming the fibers are on a square spacing of 120 mm center-to-center; and (c) membrane surface area per unit volume of module (packing density) m2/m3. Compare your re
Answer Preview: (a) Number of hollow fibers in the module = 4,000ft2/42mm i d x85mm o d x …

, Chapter: 13 -Problem: 13 >> How does the explicit-Euler method differ from the implicit method?
Answer Preview: The explicit-Euler method is popularly used as an implicit-Euler method. The difference …

, Chapter: 11 -Problem: 15 >> In reactive distillation, does the reaction preferably take place in the vapor or in the liquid phase? Can a homogeneous or solid catalyst be used?
Answer Preview: In reactive distillation, the reaction takes place in the liquid phase. This is because the vapo…

, Chapter: 19 -Problem: 13 >> A pilot-plant rotary-drum vacuum filter, with 10 ft2 of filter area in tests involving a new product, delivers 9 ft3 /minute (cfm) of filtrate at a total pressure differential of 15 psi. The drum rotates at 2.5 rpm and 25% of the drum is submerged in the feed reservoir. The pilot-plant data are to be used to design a large plant unit, made by the same manufacturer, to deliver 100 cfm of filtrate.
Answer Preview: Solution; p = P/A = 106/0 2 = 5 x 105 N/m2 (a) Since: p/t = (P)…

, Chapter: 18 -Problem: 5 >> For what types of wet solids can fluidized-bed, spoutedbed, and pneumatic-conveyor dryers be used?
Answer Preview: Fluidized bed dryers (FBDs) are used extensively for the drying of wet particulate a…

, Chapter: 18 -Problem: 14 >> What are the two most applied theories to the falling-rate drying period?
Answer Preview: Alfred P. Sloan's The General Rate of Return argument proposes that a …

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, Chapter: 19 -Problem: 9 >> Why is centrifugal force frequently applied to speed up and facilitate particle-fluid separation?
Answer Preview: Centrifuges are used to separate particles from a suspension or to …

, Chapter: 17 -Problem: 9 >> Does the solubility of most inorganic compounds in water increase or decrease with temperature?
Answer Preview: Experimentally it has been observed that the solubility of most inorganic com…

, Chapter: 12 -Problem: 7 >> What are component-coupling effects in mass-transfer-rate equations?
Answer Preview: Component-coupling effects in mass-transfer-rate equat…

, Chapter: 14 -Problem: 12 >> What is pervaporation?
Answer Preview: Pervaporation is a membrane process comparable to distillation [ 1] , and combines …

, Chapter: 12 -Problem: 17 >> A bubble-cap tray absorber is designed to absorb 40% of the propane from a rich gas at 4 atm. The specifications for the entering rich gas and absorbent oil are as follows:(a) Determine the number of equilibrium stages required and the splits of all components. (b) Determine the actual number of trays required and the splits and Murphree vapor-tray efficiencies of all components. Discuss and compa
Answer Preview: To determine the number of equilibrium stages required and the splits of all components, we need to …

, Chapter: 12 -Problem: 3 >> For which situations does the Murphree efficiency appear to be adequate? What are its deficiencies?
Answer Preview: The Murphree efficiency is an empirical function found in the proces…

, Chapter: 11 -Problem: 19 >> Design a three-column distillation sequence to separate 150 mol/s of an azeotropic mixture of ethanol and water at 1 atm into nearly pure ethanol and nearly pure water using heterogeneous azeotropic distillation with benzene as the entrainer.
Answer Preview: 1. The first column would operate at a reflux ratio of 2 to …

, Chapter: 10 -Problem: 6 >> What are the four methods most widely used to solve the MESH equations?
Answer Preview: There are four most widely used methods to solve the MESH equations: 1. Averag…

, Chapter: 12 -Problem: 4 >> What unusual phenomena did Toor find for diffusion in a ternary mixture? Is a theory available to predict these phenomena?
Answer Preview: Toor found that diffusion varies when dealing with a ternary mixture. His results showed that the ti…

, Chapter: 18 -Problem: 6 >> What is psychrometry?
Answer Preview: Psychrometry is a technique in which the relative humidity and temperature of …

, Chapter: 13 -Problem: 1 >> How does batch distillation differ from continuous distillation?
Answer Preview: Batch vs Continuous Distillation Batch distillation is …

, Chapter: 17 -Problem: 13 >> In physical adsorption, the resistance to the rate of adsorption at the solid–fluid interface is negligible. Is that also true for the incorporation of the solute into the crystal-lattice structure for solution crystallization? If not, why?
Answer Preview: The incorporation of the solute into the crystal structure is known as solution crystallization. Sin…

, Chapter: 13 -Problem: 10 >> What are the assumptions of the rigorous-batch distillation model of Distefano?
Answer Preview: 1. The more rigorous the distillation, the higher alcohol content that is achieved 2. Distefano's m…

, Chapter: 17 -Problem: 35 >> A bar of 98 wt% Al with 2 wt% of Fe impurity is subjected to one pass of zone refining. The solid–liquid distribution coefficient for the impurity is 0.29. If z/l = 10 and the resulting bar is cut off at z2 = 0.75z, calculate the concentration profile for Fe and the average concentration from (1) in Exercise 17.33. Exercise 17.33Derive the following expression for the average impurity concentratio
Answer Preview: The concentration profile for Fe can be calculated using the followi…

, Chapter: 10 -Problem: 6 >> Wang and Henke [1] state that their method of solving the tridiagonal matrix for the liquid-phase mole fractions does not involve subtraction of nearly equal quantities. Prove this.
Answer Preview: The authors state that the following equation is used to solve the tridiagonal matrix: Matrix-form s…

, Chapter: 15 -Problem: 3 >> In adsorption processes, what distinguishes purification from bulk separation?
Answer Preview: Because adsorbents are selective, purificati…

, Chapter: 7 -Problem: 31 >> A saturated-liquid feed of 40 mol% n-hexane (H) and 60 mol% n-octane is to be separated into a distillate of 95 mol% H and a bottoms of 5 mol% H. The reflux ratio L / D is 0.5, and a cooling coil submerged in the liquid of the second plate from the top removes sufficient heat to condense 50 mol% of the vapor rising from the third plate down from the top. The x–y data of Figure 7.37 may be used. (a
Answer Preview: (a) To derive the equations needed to locate the operating lines for the distillation column, we will first need to calculate the flow rates of the li…

, Chapter: 19 -Problem: 7 >> What empirical equations, with constants obtained from experimental data, are frequently used to design many particle-fluid separation devices?
Answer Preview: Darcy's Law and Fick's First Law of Diffusion. For particle-fluid separation, Darcy's law is used …

, Chapter: 10 -Problem: 7 >> How do equation-tearing and Newton–Raphson procedures differ?
Answer Preview: To tear an equation, you would need to repeatedly subtract one number from another …

, Chapter: 17 -Problem: 4 >> What is the difference between crystallization and desublimation?
Answer Preview: Crystallization is a method of purification of a substance but …

, Chapter: 15 -Problem: 1 >> Porous particles of activated alumina have a BET surface area of 310 m2/g, ?p = 0:48, and ?p = 1.30 g/cm3. Determine: (a) Vp in cm3/g; (b) ?s, in g/cm3; and (c) dp in A.
Answer Preview: (a) Vp in cm3/g: Vp = 3(2)(310)2/(0 48)(1 30)gh where =3 1416 and h=0 0118 m s, in g/cm3: s = 0:35(T…

, Chapter: 19 -Problem: 18 >> Why are pump characteristic curves important in pressure filtration?
Answer Preview: Pump characteristic curves are important in pressure filtration becaus…

, Chapter: 12 -Problem: 18 >> A ternary mixture of methanol, ethanol, and water is distilled in a sieve-tray column to obtain a distillate with not more than 0.01 mol% water. The feed to the column is as follows: Transcribed Image Text: Flow rate, kmol/h Pressure, atm Temperature, K Mole fractions: Methanol Ethanol Water 142.46
Answer Preview: The aim is to obtain a distillate with not more than 0 01 mol% water. The feed to the column is as f…

, Chapter: 19 -Problem: 5 >> What criteria have been developed for deciding which settling equation is applicable for a given particle diameter?
Answer Preview: The settling equation that is applicable for a given particle diameter depends o…

, Chapter: 13 -Problem: 5 >> What is the easiest way to determine the average composition of the distillate from a batch rectifier?
Answer Preview: The use of a batch rectifier often results in the distillate being significantly different from the …

, Chapter: 19 -Problem: 15 >> Filtration tests were carried out with a plate-and-frame filter press at 20°C under the following conditions: ?s = 2,710 kg/m3, filter area 0.37 m2, filtrate m = 0.001 N-s/m2, and cF = 10.037 kg/m3.The filter pump was controlled manually until the pressure became constant at 150,000 N/m2, which occurred at approximately V = 0.3 m3, t = 3,686 s. Make a plot of the data, t/V versus V, and determine
Answer Preview: Answer: The data can be plotted on a graph of t/V versus V to determi…

, Chapter: 13 -Problem: 17 >> What is varied to achieve optimal control?
Answer Preview: Optimal control problem Optimal control deals with …

, Chapter: 19 -Problem: 12 >> For what particle-size and particle-concentration ranges are vacuum rotary-drum, leaf, and plate-and-frame filters generally used?
Answer Preview: Dirt, particles smaller than 0 5 microns, and particles greater than 10 microns require vacuum rotar…

, Chapter: 13 -Problem: 4 >> For what kinds of mixtures is differential distillation adequate?
Answer Preview: Differential distillation is the process of removing a mixture's …

, Chapter: 19 -Problem: 3 >> Into what four regions are settling equations for particles divided?
Answer Preview: ground state excited state ionization, and de-excitati…

, Chapter: 11 -Problem: 28 >> Cygnarowicz and Seider [Ind. Eng. Chem. Res., 28, 1497–1503 (1989)] present a design for the supercritical extraction of acetone from water with CO2 using the GC-EOS method of Skjold– Jørgensen to estimate phase equilibria. Repeat their design using the Peng–Robinson EOS with the Wong–Sandler mixing rules. How do the designs compare?
Answer Preview: The designs compare by supercritical-pressure and subcritical-temperature. For example, for the Peng…

, Chapter: 19 -Problem: 20 >> A dilute aqueous slurry of viscosity 0.001 N-s/m2 and density 1,000 kg/m3 is to be separated from the solid particles, which have a density of 3,000 kg/m3, by centrifugal sedimentation. Pilot-plant runs at a feed rate of 10 X10–6 m3/s using a disc-stack centrifuge, shown in Figure 19.34, with n = 20 disks; a disk angle, u, of 45from the vertical; an outer radius R0 = 0.075 m and an internal radiu
Answer Preview: To determine the required feed rate for the plant-scale disc centrifuge, we need to use the sigma sc…

, Chapter: 1 -Problem: 22 >> An AAV viral gene vector must be purified from an anchoragedependent cell line. Repeat Exercise 1.21 to develop a purification process for this vector. Data From Exercise 1.21Recombinant protein production from E. coli resulted in the first products from biotechnology. (a) List the primary structures and components of E. coli that must be removed from a fermentation broth to purify a heterologous
Answer Preview: a) In order to purify a heterologous protein product from a fermentation broth of E. coli, the primary structures and components that must be removed …

, Chapter: 9 -Problem: 8 >> What is internal reflux? How does it differ from external reflux? Does the Underwood equation compute internal or external reflux? How can one be determined from the other?
Answer Preview: External reflux is when the stomach's contents leak out from around the lower end of the esophagus. …

, Chapter: 18 -Problem: 10 >> Under what drying conditions is the moisture-evaporation temperature equal to the wet-bulb temperature?
Answer Preview: Wet bulb temperature(WBT) can be greater than Dry Bulb Temperature(…

, Chapter: 14 -Problem: 29 >> Derive a general expression for the minimum filter area requirement per a sterility assurance limit (SAL) in terms of(a) Concentration of microorganisms in the feed; (b) Volume per unit parenteral dose; (c) Sterility assurance limit; and (d) Filter capacity.
Answer Preview: (a) According to the official compendium, the minimum filter area A [m2…

, Chapter: 9 -Problem: 19 >> One hundred kmol/h of a three-component bubble-point mixture to be separated by distillation has the composition:(a) For a distillate rate of 60 kmol/h, five stages, and total reflux, calculate the distillate and bottoms compositions by the Fenske equation. (b) Using the separation in part (a) for components B and C, determine Rmin and minimum boilup ratio by the Class 2 Underwood equations. (c) F
Answer Preview: To solve this problem, we first need to determine the relative volatilities of the three components. …

, Chapter: 19 -Problem: 10 >> Why have theoretical analyses that treat voids in filter cakes as flow channels not been applied industrially?
Answer Preview: Industrys adoption of theoretical analyses that treat voids in filter cakes as flow channels has bee…

, Chapter: 10 -Problem: 16 >> Would it be expected that for a given problem, the NR and inside-out methods converge to the same result?
Answer Preview: The National Research Council and the inside-out met…

, Chapter: 10 -Problem: 5 >> Use the Thomas algorithm to solve the following tridiagonal matrix equation for the x vector. Transcribed Image Text: -6 3 0 1.5 0 0 3 0 -4.5 3 0 0 0 0 3 4.5 -7.5 0 4.5 -7.5 0 0 0 3 -4.5 X1 X2 X3 X4 X5 0 100 0 0
Answer Preview: To use the Thomas algorithm, we need to first rewrite the tridiagonal matrix equation in the form of …

, Chapter: 19 -Problem: 15 >> Why are wash periods followed by expression often part of the filtering cycle?
Answer Preview: Primarily, this is due to the space in between the washer and …

, Chapter: 14 -Problem: 28 >> Derive a general expression for the total filtration time necessary to filter a given feed volume V using the pore-constriction model. From this expression, predict the average volumetric flux during a filtration and the volumetric capacity necessary to achieve a given filtration time, based on laboratory-scale results.
Answer Preview: T = Q V / (1 + fd) Where d is the pore-constriction diameter, Q is the feed volume, and fd is a dime…

, Chapter: 9 -Problem: 24 >> For the flashing and stripping operation in Figure 9.27, determine by the Kremser method the kmol/hr of steam if the stripper is operated at 2 atm with five stages. Transcribed Image Text: 145ºF C? Ca C? nCa NCH NC 2 Valve kmol/h 13.7 101.3 146.9 23.9 5.7 196.7 2 atm -0 150ºF Figure 9.27 Data for Ex
Answer Preview: Answer: Using the Kremser method, the mass flow rate of st…

, Chapter: 17 -Problem: 8 >> What is the difference between differential screen analysis and cumulative screen analysis?
Answer Preview: Differential or Distinctive particle size dispensation is the percentage of particles from the …

, Chapter: 13 -Problem: 12 >> What is the difference between truncation error and stability?
Answer Preview: A truncation error is a common term for an overflow. Whereas stability means the degree to which a s…

, Chapter: 10 -Problem: 30 >> A depropanizer distillation column is designed to operate at a feed stage pressure of 315 psia for separating a feed into distillate and bottoms with the following flow rates:The feed is 66 mol% vapor at tower pressure. Steam at 315 psia and cooling water at 65F are available for the reboiler and condenser. Assume a 2-psi column pressure drop. (a) Should a total condenser be used for this column?
Answer Preview: a) A total condenser should be used for this column because the distillate contains all of the light …

, Chapter: 19 -Problem: 6 >> An ambient air stream at a superficial velocity of 9.84 ft/min, containing an aerosol of 1-mm-diameter particles at an estimated concentration of 104 particles/m3, is to be filtered through a bed of glass fibers, 19 mm in diameter, with a bed void fraction, ?b, of 0.0033. An empirical equation for the particle-collection efficiency as a function of bed thickness for glass fibers of this type is gi
Answer Preview: To calculate the bed depth in cm for a range of particle-collection efficiencies, you can use the equation provided: L = 0 0077(rb/b)^0 5(u s)^(-0 5)(…

, Chapter: 13 -Problem: 7 >> A still-pot is charged with 25 mol of benzene and toluene containing 35 mol% benzene. Feed of the same composition is supplied at a rate of 7 mol/h, and the heating rate is adjusted so that the liquid level in the still-pot remains constant. If ? = 2.5, how long will it be before the distillate composition falls to 0.45 mol% benzene?
Answer Preview: Solution; C = concentration of benzene (mol…

, Chapter: 10 -Problem: 15 >> What types of calculations consume the most time in the BP, SR, and NR methods? How does the inside-out method reduce this time?
Answer Preview: The BP method is the most time consuming. The SR and NR me…

, Chapter: 17 -Problem: 1 >> How does solution crystallization differ from melt crystallization?
Answer Preview: In solution crystallization, the crystals are separated away f…

, Chapter: 14 -Problem: 12 >> Using the membrane and feed conditions of and values for Rm and K2 determined in Example 14.3 for DE microfiltration, compute and plot the permeate flux and cumulative permeate volume as a function of time. Assume a combined operation with Stage 1 at a constant permeate rate of 10 mL/minute to an upper-limit pressure drop of 25 psi, followed by Stage 2 at this pressure drop until the permeate rate
Answer Preview: To compute and plot the permeate flux and cumulative permeate volume as a function of time, we need …

, Chapter: 9 -Problem: 9 >> What is the optimal range of values for R/Rmin?
Answer Preview: Step 1 The optimal range of values for the R/R min . Step 2 R is the reflux ratio while R min is the …

, Chapter: 17 -Problem: 11 >> Does the commonly reported solubility of an inorganic compound in water pertain to large crystals or small crystals? Why?
Answer Preview: The larger the molecules of the solute are, the larger is the…

, Chapter: 13 -Problem: 9 >> What effects does liquid holdup have on batch rectification?
Answer Preview: In batch rectification, one of the main concerns is liquid holdup in distillation …

, Chapter: 10 -Problem: 20 >> Calculate product compositions, stage temperatures, interstage vapor and liquid flow rates and compositions, reboiler duty, and condenser duty for the following column specifications. Feed (bubble-point liquid at 250 psia and 213.9F):Column pressure = 250 psia; partial condenser and partial reboiler; Distillate rate = 23.0 lbmol/h; reflux rate = 150.0 lbmol/hr; Number of equilibrium stages (exclu
Answer Preview: To calculate the product compositions, stage temperatures, and interstage vapor and liquid flow rate…

, Chapter: 17 -Problem: 5 >> What is the difference between mother liquor and magma?
Answer Preview: Mother liquor is the name for the hot liquid that is …

, Chapter: 13 -Problem: 7 >> What is a batch stripper?
Answer Preview: The batch stripper consists of the same parts as the batch …

, Chapter: 10 -Problem: 12 >> What limitations of the BP and SR methods are overcome by the NR methods? How do the NR methods differ from the BP and SR methods?
Answer Preview: The NR methods are free from some limitations of the BP a…

, Chapter: 19 -Problem: 5 >> A 6-inch demister pad is to be used to separate liquid entrainment from a gas in a horizontal flash drum. Calculate the demister diameter using the following data: Vapor flow rate = 465 cfm at 110°F and 50 psia; vapor density 0.30 lb/ft3; and liquid density = 33 lb/ft3, K = 0.35.
Answer Preview: H = 0 60" + (3)(0 012) = 0 72" on center Sg = cup diameter - …

, Chapter: 14 -Problem: 17 >> What is diafiltration? How does it differ from continuous feed-and-bleed ultrafiltration? Under what conditions is diafiltration used in conjunction with continuous feed-and-bleed ultrafiltration?
Answer Preview: Diafiltration is a process whereby a permeable membrane separates two miscible liquids, producing an …

, Chapter: 10 -Problem: 39 >> Calculate product rates and compositions, stage temperatures, and interstage vapor and liquid flow rates and compositions for the absorber shown in Figure 10.38. Transcribed Image Text: Lean oil, 80°F, 400 psia 250 lbmol/h Secondary oil, 80°F, 400 psia Ibmol/h 13 C1 C2 C3 588888 nC4 nC5 Oil 55556 C
Answer Preview: Answer: To calculate the product rates and compositi…

, Chapter: 15 -Problem: 8 >> Ruthven and Kaul [Ind. Eng. Chem. Res., 32, 2047–2052 (1993)] measured adsorption isotherms for a series of gaseous aromatic hydrocarbons on well-defined crystals of NaX zeolite over ranges of temperature and pressure. For 1,2,3,5-tetramethylbenzene at 547 K, the following equilibrium data were obtained with a vacuum microbalance:Obtain a best fit of the data to the linear, Freundlich, and Langmui
Answer Preview: Linear Isotherm: We can use the following equation to calc…

, Chapter: 11 -Problem: 3 >> For the same conditions as in Exercise 11.2, use a process simulator with the UNIFAC equation to calculate a portion of a distillation curve at 1 at. Data From Exercise 11.2For the system in Exercise 11.1, use a process simulator with the UNIFAC equation to calculate a portion of a residue curve at 1 atm starting from a bubble-point liquid with 20 mol% normal hexane, 60 mol% methanol, and 20 mol%
Answer Preview: The UNIFAC equation is: q = xA(1-xB) + xB(1-xA) where q is t…

, Chapter: 11 -Problem: 9 >> What is a distillation-curve map? How does it differ from a residue-curve map?
Answer Preview: A distillation-curve map is a diagram showing the heat distribution in a distillation setup. It is a…

, Chapter: 17 -Problem: 3 >> What are the two main methods used to cause crystallization from an aqueous solution? Which is more common and why?
Answer Preview: Sometimes when aqueous solutions are cooled to below their freezing point, molecules of water freeze …

, Chapter: 15 -Problem: 1 >> How is a large surface area achieved for adsorption?
Answer Preview: When a gas is adsorbed, it means that the gas molecules are attracted so much to …

, Chapter: 9 -Problem: 4 >> For the deethanizer in Figure 9.21, estimate the number of stages, assuming it is equal to 2.5 times Nmin. Transcribed Image Text: Comp. kmol/h 160 370 55836 C? C? 90°F C? RCA RC? 240 25 5 a, average Comp. relative volatility 55530 2 kmol/h of C? C? RC? Cs 8.22 2.42 1.00 0.378 0.150 2 kmol/h of C?
Answer Preview: ANSWER The number of stages in a distillation column is dependent on several factors such as the com…

, Chapter: 17 -Problem: 12 >> What is supersaturation? Under what conditions is it possible to supersaturate a solution? What is the metastable region?
Answer Preview: Supersaturation is defined as the difference between the solute concentratio…

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, Chapter: 9 -Problem: 14 >> A feed of 62 mol% para-dichlorobenzene in ortho-dichlorobenzene is separated by distillation at near-atmospheric pressure into a distillate containing 98 mol% para isomer and bottoms of 96 mol% ortho isomer. If a total condenser and partial reboiler are used, ? = 0.9, average a = 1.154, and R/Rmin = 1.15, use the FUG procedure to estimate the theoretical stages required.
Answer Preview: I can use the FUG procedure by plugging in the values of k, alpha, and and finding their values. The…

, Chapter: 7 -Problem: 22 >> A bubble-point feed of 5 mol% A in B is to be distilled to give a distillate containing 35 mol% A and a bottoms containing 0.2 mol%. The column has a partial reboiler and a partial condenser. If a = 6, calculate the following algebraically: (a) The minimum number of equilibrium stages; (b) The minimum boilup ratio V / B; (c) The actual number of stages for a boilup ratio equal to 1.2 times the min
Answer Preview: (a) To find the minimum number N = (35 0 2)/(0 05 + 0 05) = 63 stages This is the same …

, Chapter: 19 -Problem: 18 >> Talc is to be filtered at a constant filtration rate under conditions listed below. The pressure drop is expected to rise from 2.0 psi to 100 psi. Generate a table of pressure versus time at 10, 20, 40, 60, 80, and 100 psi. Assume Rm in (19-27) is negligible, but justify your assumption. Obtain aavg by integrating (19-26), which gives ?avg = (1 – s)?'(?P)s [23]. The conditions are: percent solids
Answer Preview: Solution; (19-26) (Gross form of differential equati…

, Chapter: 12 -Problem: 5 >> In the rate-based model, is the assumption of phase equilibrium used anywhere? If so, where? Is it justified?
Answer Preview: Phase equilibrium is a concept in thermodynamics where a system in thermal equilibrium must have the …

, Chapter: 4 -Problem: 5 >> For the seven-phase equilibrium system shown in Figure 4.30, assume air consists of N2, O2, and argon. What is the number of degrees of freedom? What variables might be specified? Transcribed Image Text: Air n-hexane-rich. liquid Aniline-rich liquid Water-rich liquid Phosphorous liquid Gallium liqui
Answer Preview: The number of degrees of freedom for a seven-phase equilibrium system is 6. The variabl…

, Chapter: 18 -Problem: 11 >> Distinguish among total-moisture content, free-moisture content, equilibrium-moisture content, unbound moisture, and bound moisture.
Answer Preview: Total moisture content is the amount of water in a soil without any ot…

, Chapter: 14 -Problem: 25 >> The separation of benzene (B) from cyclohexane (C) by distillation at 1 atm is impossible because of a minimum-boiling-point azeotrope at 54.5 mol% benzene. However, extractive distillation with furfural is feasible. For an equimolar feed, cyclohexane and benzene products of 98 and 99 mol%, respectively, can be produced. Alternatively, the use of a three-stage pervaporation process, with selectivi
Answer Preview: a. The flow rates of retentate = Qr = (1 43 kg/h)/(53 16 kJ…

, Chapter: 4 -Problem: 64 >> It is proposed that oxygen be separated from nitrogen by absorbing and desorbing air in water. Pressures from 101.3 to 10,130 kPa and temperatures between 0 and 100?C are to be used. (a) Devise a scheme for the separation if the air is 79 mol% N2 and 21 mol% O2. (b) Henry’s law constants for O2 and N2 are given in Figure 4.26. How many batch absorption steps would be necessary to make 90 mol% oxyg
Answer Preview: Answer. a. A scheme for the separation is as follows: 1. Charge the column with air at 101 …

, Chapter: 17 -Problem: 40 >> A 10 wt% aqueous solution of NaOH at 100°F and a flow rate of 30,000 lb/h is to be concentrated to 50 wt% by evaporation using saturated steam at 115 psia. (a) If a single-effect evaporator is used with U = 400 Btu/h-ft2-°F and a vapor-space pressure of 4 inches Hg, determine the heat-transfer area and the economy. (b) If a doubleeffect evaporator system is used with forward feed and U1 = 450 Btu
Answer Preview: (a) Heat-transfer area, A = …

, Chapter: 14 -Problem: 30 >> Based on the problem statement of Example 14.20, calculate for just Section 1 the component material balance in pounds per day of operation, the percent recovery (yield) from the whey of the TP and NPN in the final concentrate, and the number of cartridges required if two stages are used instead of four. Example  14.20A cheese plant produces a byproduct stream of 1,000,000 lb/day of  whey, to be f
Answer Preview: Answer: Section 1: Component material balances in lb/day of operation: Fresh Feed = 1,000,000 lb/day …

, Chapter: 11 -Problem: 4 >> What are the two reasons for conducting reactive distillation?
Answer Preview: A) To remove any poisonous or …

, Chapter: 19 -Problem: 4 >> What form of the Souders–Brown equation is used to correlate empirical settling data?
Answer Preview: The form of the SoudersBrown equation that is used to correlate empirical settling data is the origi…

, Chapter: 10 -Problem: 7 >> Derive an equation similar to (10-7), but with vi,j = yi,j Vj as variables instead of liquid mole fractions. Can the equations still be partitioned into a series of C tridiagonal-matrix equations?
Answer Preview: Review: The tridiagonal equation is a generalization of the first approximation, (10-11). In additio…

, Chapter: 6 -Problem: 15 >> What is meant by turndown ratio? What type of tray has the best turndown ratio? Which tray the worst?
Answer Preview: To calculate a turndown ratio in a restaurant, you must divide the number of tables turned eve…

, Chapter: 16 -Problem: 12 >> How does the shrinking-core model used for mineral leaching differ from the simpler model used for leaching of food materials?
Answer Preview: In the shrinking-core model, two streams of water are used. One …

, Chapter: 13 -Problem: 13 >> An acetone–ethanol mixture of 0.5 mole fraction acetone is to be separated by batch distillation at 101 kPa. Vapor–liquid equilibrium data at 101 kPa are as follows:(a) Assuming an L=D of 1.5 times the minimum, how many stages should this column have if the desired composition of the distillate is 0.90 mole fraction acetone when the residue contains 0.1 mole fraction acetone? (b) Assume the column
Answer Preview: (a) No. of stages = D + 1 where is the efficiency factor of the column/column tray. It is given by E…

, Chapter: 4 -Problem: 40 >> In Figure 4.40, a mixture is heated and expanded before entering a distillation column. Calculate, using a process simulator, mole percent vapor and vapor and liquid mole fractions at locations indicated by pressure specifications. Transcribed Image Text: 100 lbmol/h 150°F, 260 psia ?? Heater 260°F,
Answer Preview: Answer: Based on Figure 4 40, the mixture is composed of 50 mol% of component A and 50 mol% of compo…

, Chapter: 19 -Problem: 16 >> What are the assumptions in the Ruth equation for filtration?
Answer Preview: First assumption: The flow rate is constant. Second assumption: The pressure difference across the f…

, Chapter: 14 -Problem: 21 >> Separation of air into N2 and O2 is widely practiced. Cryogenic distillation is most economical for processing 100 to 5,000 tons of air per day, while pressure-swing adsorption is favorable for 20 to 50 tons/day. For small-volume users requiring less than 10 tons/day, gas permeation finds applications where for a single stage, either an oxygen-enriched air (40 mol% O2) or 98 mol% N2 can be produce
Answer Preview: Answer: For Company A, the required membrane area is: A = (5 tons/d…

, Chapter: 1 -Problem: 15 >> Give examples of separation operations used for the steps in a bioprocess.
Answer Preview: Separation operations are the steps in a bioprocess that remove substances from the product material…

, Chapter: 19 -Problem: 9 >> Calculate, using single-fiber collection efficiencies, the overall collection efficiency of a bag filter comprised of glass fibers of mean diameter 10 mm in the form of a cloth 1-mm thick, taking into account both diffusion (Brownian motion) and impingement. The gas contains 1 g/m3 of dust of specific gravity 2 g/cm3 and has a velocity of 0.1 ft/s. The particle-size distribution is as follows:Unde
Answer Preview: To calculate the overall collection efficiency of a bag filter, we need to consider the collection e…

, Chapter: 13 -Problem: 14 >> What is stiffness and how does it arise? What criterion can be used to determine the degree of stiffness, if any?
Answer Preview: Stiffness is the inability to extend joints. The causes of stiffness include inflammation, arthritis, and ligament sprains. Some symptoms include achi…

, Chapter: 6 -Problem: 8 >> In general, why should the operating pressure be high and the operating temperature be low for an absorber, and the opposite for a stripper?
Answer Preview: Strippers are made with a high density material an…

, Chapter: 17 -Problem: 6 >> Why are crystals never spherical in shape?
Answer Preview: :Crystal growth is partially controlled by the rate of evaporatio…

, Chapter: 12 -Problem: 20 >> It is required to absorb 96% of the benzene from a gas stream with absorption oil in a sieve-tray column at a nominal pressure of 1 atm. The feed conditions are as follows:Tray geometry is as follows:Determine column diameter for 80% of flooding, the number of actual trays required, and the Murphree vapor-tray efficiency profile for benzene for the possible combinations of vapor and liquid flow pa
Answer Preview: To determine the column diameter for 80% flooding, we can use the Ergun equation: Q = 150(1 - )Gd^2/…

, Chapter: 10 -Problem: 9 >> Solve by the Newton–Raphson method the simultaneous, nonlinear equationsfor x1 and x2 to within ± 0.001. As initial guesses, assume: (a) x1 = 2, x2 = 5; (b) x1 = 4, x2 = 5; (c) x1 = 1, x2 = 1; (d) x1 = 8, x2 = 1. Transcribed Image Text: x² + x² = 17 (8x?) ¹/3 + x?/2 = 4
Answer Preview: (a) x1 = 0 0, x2 = 1 0015; …

, Chapter: 6 -Problem: 5 >> Volatile organic compounds (VOCs) can be removed from water effluents by stripping with steam or air. Alternatively, the VOCs can be removed by carbon adsorption. The U.S. Environmental Protection Agency (EPA) identified air stripping as the best available technology (BAT). What are the advantages and disadvantages of air compared to steam or carbon adsorption?
Answer Preview: Solution; The advantages of air stripping over steam or carbon adsorption are as follows: Advantages …

, Chapter: 17 -Problem: 8 >> One thousand grams of water is mixed with 50 g of Ag2CO3 and 100 g of AgCl. At equilibrium at 25°C, calculate the concentrations in mol/L of Ag+, Cl–, and CO2–3 ions and g of Ag2CO3 and AgCl in the solid phases.
Answer Preview: The chemical mass of Ag 2 CO 3 =(107 86*2+12+3*16)g=275 72g The chemical mass of AgC…

, Chapter: 12 -Problem: 11 >> A sieve-tray column, operating at a nominal pressure of 1 atm, is used to separate a mixture of acetone and methanol by extractive distillation using water. The column has 40 trays with a total condenser and partial reboiler. The feed of 50 kmol/h of acetone and 150 kmol/h of methanol at 60?C and 1 atm enters Tray 35 from the top, while 50 kmol/h of water at 65?C and 1 atm enters Tray 5 from the t
Answer Preview: Solution; The feed to the column is considered using two-phase equilibrium and plug flow assumption…

, Chapter: 1 -Problem: 16 >> Ethanol and benzene are separated in a network of distillation and membrane separation steps. In one step, a near-azeotropic liquid mixture of 8,000 kg/h of 23 wt% ethanol in benzene is fed to a pervaporation membrane consisting of an ionomeric film of Ethanol and benzene are separated in a network of distillation and membrane separation steps. In one step, a near-azeotropic liquid mixture of 8,00
Answer Preview: (a) The flow diagram of the pervaporation step using symbols from Table 1 2 is as follows: yaml Copy …

, Chapter: 5 -Problem: 3 >> What is the limitation of a single-section cascade? Does a two-section cascade overcome this limitation?
Answer Preview: A cascade is limited to a single section of hair because it requir…

, Chapter: 18 -Problem: 4 >> For what types of wet solids can fluidized-bed, spoutedbed, and pneumatic-conveyor dryers be used?
Answer Preview: Moisture content of solids is less than 10% Melting point of water (ice) is at or below 0C Soluti…

, Chapter: 11 -Problem: 18 >> A mixture of 16,500 kg/h of 55 wt% methyl acetate and 45 wt% methanol is to be separated into 99.5 wt% methyl acetate and 99 wt% methanol. Use of one homogeneous azeotropic distillation column and one ordinary distillation column has been suggested. Possible entrainers are n-hexane, cyclohexane, and toluene. Determine feasibility of the sequence. If feasible, prepare a design. If not, suggest an a
Answer Preview: Calculation. The minimum reflux ratio for a binary mixt…

, Chapter: 9 -Problem: 7 >> For the distillation in Figure 9.23, calculate Nmin and the distribution of the nonkey components by the Fenske equation, using Figures 2.4 and 2.5 for K-values. Transcribed Image Text: C3 iCa nC4 iC5 nC? nC6 kmol/h 2,500 400 600 100 200 40 50 40 700 kPa nC7 nCg Figure 9.23 Data for Exercise 9.7. HK
Answer Preview: Answer: Nmin = (xA)top / (xA)bot Nmin = (0 8) / (0 2) …

, Chapter: 4 -Problem: 74 >> A liquid of 30 mol% toluene, 40 mol% ethylbenzene, and 30 mol % water is subjected to a continuous flash distillation at 0.5 atm. Assuming that mixtures of ethylbenzene and toluene obey Raoult’s law and that the hydrocarbons are immiscible in water and vice versa, calculate the temperature and composition of the vapor phase at the bubble-point temperature.
Answer Preview: At the equilibrium point of mixture, the Gibbs free energy of the system is G=rngaFrn…

, Chapter: 17 -Problem: 42 >> Belter et al. [43] report that cooled batch crystallization of tetracycline in mixed solvents exhibits linear changes in solubility with temperature: 1.14 x 10–3 g antibiotic/cm3 solvent/K. Suppose 0.01- cm seeds (? = 1.06 g/cm3) are added at 27 ?g/cm3 to obtain 0.095- cm crystals at supersaturation of about 0.077 g/cm3. Calculate the cooling curve for this process, assuming constant, diffusion co
Answer Preview: The process time and fractional increase in product size per seed = …

, Chapter: 12 -Problem: 9 >> Can the rate-based model be applied to packed columns?
Answer Preview: Yes. The rate-based model can be applied to packed …

, Chapter: 10 -Problem: 11 >> Does the SR method use tridiagonal-matrix equations? How does the SR method differ from the BP method? For what types of problems is the SR method preferred over the BP method? What are the tear variables in the SR method?
Answer Preview: The SR (Successive over-relaxation) method is a technique used to solve linear systems of equations …

, Chapter: 4 -Problem: 8 >> What is the difference between an isothermal and an adiabatic flash?
Answer Preview: The major difference between these two types of processes is t…

, Chapter: 19 -Problem: 12 >> A slurry is being filtered in a plate-and-frame filter press at a constant pressure drop of 10 psi under conditions where the resistance of the medium is negligible. The fluid viscosity is 2.0 lb/hr-ft; 5 lb of dry cake are collected for every ft3 of filtrate; and the cake is incompressible, with a specific cake resistance, ?, of 8.34x 1010 ft/lbm. What filter area is required to process 50 ft3 i
Answer Preview: After the initial calculation, one must consider the momentum of the fluid and its viscosity. The mo…

, Chapter: 12 -Problem: 4 >> The following results were obtained at tray n from a rate-based calculation at 14.7 psia, for a ternary mixture of acetone (1), Methanol (2), And water (3) In a sieve-tray column assuming that both phases are perfectly mixed.The products of the computed gas-phase, binary mass-transfer coefficients, and interfacial area from the Chan–Fair correlations are as follows in units of lbmol/(h-unit mole f
Answer Preview: To determine the component molar diffusion rates, mass-transfer rates, and Murphree vapor-tray efficiencies for the given ternary mixture in a sieve-t…

, Chapter: 10 -Problem: 23 >> In Exercise 10.20 provide a 200,000 Btu/hr intercooler on the fourth stage from the top and a 300,000 Btu/h interheater on the fourth stage from the bottom. Data From Problem Exercise 10.20Calculate product compositions, stage temperatures, interstage vapor and liquid flow rates and compositions, reboiler duty, and condenser duty for the following column specifications. Feed (bubble-point liquid a
Answer Preview: Solution; General Intercooler duty: R* = …

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, Chapter: 19 -Problem: 16 >> A slurry is passed through a filter cloth 0.02 m2 in area at a constant rate, with 4 x 10–5 m3/s of filtrate being collected. After 100 s, the pressure is 4 x 104 N/m2; after 500 s, it is 1.2 x 105 N/m2. The same filter-cloth material will be used in a plate-and-frame filter press having an area of 0.5 m2, which can hold a cake of thickness, L, of 0.04 m, and which will process the same slurry. As
Answer Preview: Solution; p = P/A = 106/0 2 = 5 x 105 N/m2 (a) Since: p/t = (P)…

, Chapter: 13 -Problem: 11 >> Why is the Distefano model referred to as a differentialalgebraic equation (DAE) system?
Answer Preview: The term DAE is …

, Chapter: 9 -Problem: 20 >> For the conditions of Exercise 9.6, determine the ratio of rectifying to stripping equilibrium stages by the: (a) Fenske equation, (b) Kirkbride equation, and (c) McCabe–Thiele diagram. Discuss your results. Data From Exercise 9.6A 25 mol% mixture of acetone (A) in water (W) is to be separated  by distillation at 130 kPa into a distillate containing 95 mol%  acetone and a bottoms of 2 mol% acetone
Answer Preview: Answer: (a) Fenske Equation: The ratio of rectifying to stripping equilibrium stages by the Fenske equation can be calculated using the following equa…

, Chapter: 4 -Problem: 19 >> In a rigorous vapor–liquid–liquid equilibrium calculation (the so-called three-phase flash), is it necessary to consider all possible phase conditions, i.e., all-liquid, all-vapor, vapor–liquid, liquid– liquid, as well as vapor–liquid–liquid?
Answer Preview: Yes, it is. The phenomena of the vapor saturation at the single-phase equilibrium process (vaporliqu…

, Chapter: 19 -Problem: 24 >> A rotor-stator cell disruptor consists of a tapered cavity (stator) and a cone-shaped rotating rotor. The cell suspension is pumped through the very small gap between the rotor and stator, thus being disrupted by the high shear rate. It was found that at a residence time of 10 s, an intracellular antibiotic release was 2.65 mg/mL, and at a residence time of 30 s, it was 4.77 mg/ mL. If the residen
Answer Preview: a. The concentration of antibioti…

, Chapter: 13 -Problem: 15 >> In the development of an operating policy (campaign) for batch distillation, what is done with intermediate (slop) cuts?
Answer Preview: Intermediate cuts are distillate which is too contaminate…

, Chapter: 9 -Problem: 5 >> Is use of the Fenske equation restricted to the two key components? If not, what else can the Fenske equation be used for besides the estimation of the minimum number of equilibrium stages, corresponding to total reflux?
Answer Preview: The equation is not restricted to the frictions for two key components only. This is just a convenie…

, Chapter: 6 -Problem: 3 >> Bubble-cap trays were widely used in towers prior to the 1950s. Today sieve and valve trays are favored. However, bubble-cap trays are still specified for operations that require very high turndown ratios or appreciable liquid residence time. What characteristics of bubble-cap trays make it possible for them to operate satisfactorily at low vapor and liquid rates?
Answer Preview: Solution; The characteriistics that makes bubble-cap trays suitable for low vapor and liquid ra…

, Chapter: 18 -Problem: 1 >> What are the most commonly employed modes of heat transfer for drying? Does the temperature of the solid during drying depend on the mode?
Answer Preview: The most commonly employed modes of heat transfer for drying are conv…

, Chapter: 14 -Problem: 24 >> For a temperature of 60°C and a permeate pressure of 15.2 mmHg, Wesslein et al. [45] measured a total permeation flux of 1.6 kg/m2-h for a 17.0 wt% ethanol-in-water feed, giving a permeate of 12 wt% ethanol. Otherwise, conditions were those of Example 14.13. Calculate the permeances of ethyl alcohol and water for these conditions. Also, calculate the selectivity for water. Example 14.13Consider th
Answer Preview: To calculate the permeances of ethanol and water, we need to know the total permeation flux and the …

, Chapter: 9 -Problem: 5 >> For the complex distillation in Figure 9.22, use the Fenske equation to determine Nmin between the: (a) Distillate and feed, (b) Feed and sidestream, and (c) Sidestream and bottoms. Use Raoult’s law for K-values. Transcribed Image Text: 130 kPa Feed 165 kPa kmol/h Benzene 260 80 Toluene Biphenyl 5 2
Answer Preview: Answer: (a) Nmin = (1/0 3 - …

, Chapter: 4 -Problem: 36 >> A solution at 107?C contains 50 mol% water (W) and 50 mol% formic acid (F). Using (2-72) with vapor pressure data and the van Laar equation with AWF = -0.2935 and AFW = 0.2757: (a) Compute the bubble-point pressure. (b) Compute the dew-point pressure. (c) Determine if the mixture forms an azeotrope. If so, predict the azeotropic pressure at 107?C and the composition.
Answer Preview: (a) The bubble-point pressure = 0 80 bar (b) The dew-point pressure = 2 52 bar (c) A…

, Chapter: 19 -Problem: 8 >> Why do governmental regulatory agencies and trade organizations set many design and performance specifications for particle emissions?
Answer Preview: To ensure the public's safe consu…

, Chapter: 12 -Problem: 8 >> Does the rate-based model account for the bulk-flow effect in mass transfer?
Answer Preview: The rate-based model describes the mass transfer in a liquid phas…

, Chapter: 10 -Problem: 12 >> Solve the nine simultaneous linear equations below, which have a block-tridiagonal-matrix structure, by the Thomas algorithm: Transcribed Image Text: x2 + 2x3 +2x4+x6 = 7 X? + x3 + x4 + 3x5 = 6 x? + x? + x3 + x5 + x6 = 6 X4 + 2x5 + X6 + 2x7 + 2x8 + X9 = 11 x4+x5 + 2x6 + 3x7 +x9 = 8 x5 + X6 + X7 + 2
Answer Preview: X1=1, X2=2, X3=3, X4=2, X5=5, X6=2, X7=1, X8=2, X9=2 To solve this system of equations using th…

, Chapter: 5 -Problem: 6 >> Under what conditions can a countercurrent cascade achieve complete extraction?
Answer Preview: A countercurrent cascade is a type of heat pump which can answe all the heat from a fluid, typically a gas. It works well with fluids that have low …

, Chapter: 15 -Problem: 7 >> The separation of propane and propylene is accomplished by distillation, but at the expense of more than 100 trays and a reflux ratio greater than 10. Consequently, the use of adsorption has been investigated in a number of studies. Jarvelin and Fair [Ind. Eng. Chem. Research, 32, 22012207 (1993)] measured adsorption-equilibrium data at 25°C for three different zeolite molecular sieves (ZMSs) and
Answer Preview: (a) Based on the Langmuir isotherm constants, propylene is most strongly adsorbed by all three zeoli…

, Chapter: 15 -Problem: 10 >> In Example 15.6, pure-component, liquid-phase adsorption data are used with the extended-Langmuir isotherm to predict a binarysolute data point. Use the mixture data below to obtain the best fit to an extended-Langmuir–Freundlich isotherm of the formData for binary-mixture adsorption on activated carbon (1,000 m2/g) at 25°C for acetone (1) And propionitrile (2) Are:Example 15.6Small amounts of VOC
Answer Preview: To fit the binary data to the extended Langmuir-Freundlich isotherm, we need to determine the values of the parameters k1, k2, n1, and n2 in the follo…

, Chapter: 14 -Problem: 31 >> Based on the problem statement of Example 14.20, design a four-stage diafiltration section to take the 55 wt% concentrate from Section 1 and achieve the desired 85 wt% concentrate, thus eliminating Section 3. Example  14.20A cheese plant produces a byproduct stream of 1,000,000 lb/day of  whey, to be further processed to obtain a dry powder containing 85  wt% combined TP (true protein) and NPN (no
Answer Preview: To eliminate Section 3 and achieve the desired 85 wt% concentrate, a four-stage diafiltration section needs to be designed. In this section, the reten…

, Chapter: 9 -Problem: 11 >> When can a serious problem arise with the Gilliland correlation?
Answer Preview: This is a problem of causation and correlation. Specifically…

, Chapter: 4 -Problem: 15 >> What is the difference between adsorbent and adsorbate?
Answer Preview: Adsorbate refers to the molecular species th…

, Chapter: 17 -Problem: 2 >> Under what conditions does precipitation occur?
Answer Preview: Precipitation forms in the clouds when water vapor c…

, Chapter: 15 -Problem: 15 >> Ion exclusion is a process that uses ion-exchange resins to separate nonionic organic compounds from ionic species contained in a polar solvent, usually water. The resin is presaturated with the same ions as in the solution, thus eliminating ion exchange. However, in the presence of the polar solvent, resins undergo considerable swelling by absorbing the solvent. Experiments have shown that a noni
Answer Preview: To determine the amount of resin required, we need to calculate the volume of resin needed to absorb …

, Chapter: 11 -Problem: 20 >> Design a three-column distillation sequence to separate 120 mol/s of an azeotropic mixture of isopropanol and water at 1 atm into nearly pure isopropanol and nearly pure water using heterogeneous azeotropic distillation with benzene entrainer.
Answer Preview: 1. The first column would operate at a temperature slightly below the azeotrope of the is…

, Chapter: 10 -Problem: 4 >> For a cascade of N countercurrent equilibrium stages, what is the number of variables, number of equations, and number of degrees of freedom? What are typical specifications, and what are the typical computed (output) variables? Why is it necessary to specify the number of equilibrium stages and the locations of all sidestream withdrawals and heat exchangers?
Answer Preview: S = N (number of equilibrium stages) -1 (one for the feed) Equations: DoF = S + 1 (one for the entha…

, Chapter: 6 -Problem: 10 >> What is the difference between an operating line and an equilibrium curve?
Answer Preview: An equilibrium curve has one price and quantity at each point on the curve while an operatin…

, Chapter: 16 -Problem: 8 >> Derive (16-20), assuming that (Yi)b, kc, m, and a are constants and that (Xi)o is uniform through the solid.
Answer Preview: x = (a/kc)y + Yi where x, y and z are real numbers. …

, Chapter: 15 -Problem: 20 >> In chromatography, what causes different solutes to pass through the chromatograph with different residence times?
Answer Preview: Chromatography is a method wherein molecules in a mixture are applied onto the surface of solid or f…

, Chapter: 13 -Problem: 6 >> Which is easiest to implement: (1) The constant-reflux policy, (2) The constant-distillate-composition policy, or (3) The optimal- control policy? Why?
Answer Preview: (1) The constant-reflux policy is a method of policy refinement for continuous processes. The idea i…

, Chapter: 9 -Problem: 11 >> For the conditions of Exercise 9.7, with bubble-point liquid feed at column pressure, compute the minimum external reflux and nonkey distribution at Rmin by the Class 2 Underwood equations. Data From Exercise 9.7For the distillation in Figure 9.23, calculate Nmin and the distribution of the nonkey components by the Fenske equation, using Figures 2.4 and 2.5 for K-values.
Answer Preview: The Class 2 Underwood equations give the following values for the minimum externa…

, Chapter: 5 -Problem: 2 >> What is the difference between a countercurrent and a crosscurrent cascade?
Answer Preview: In countercurrent flow, the fresh streams enter at oppos…

, Chapter: 17 -Problem: 10 >> Can an inorganic compound have more than one form of hydrate?
Answer Preview: No. A hydrate is a compound that contains water or its cons…

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, Chapter: 12 -Problem: 1 >> For binary distillation, what assumption did Smoker add to the McCabe–Thiele assumptions to obtain an algebraic solution?
Answer Preview: Smoker made the assumption that all of the McCabeThiele process would …

, Chapter: 9 -Problem: 12 >> Calculate and plot the external Rmin and Nmin against % product purity for the separation by distillation of an equimolar bubble-point liquid feed of isobutane/n-butane at 100 psia. The distillate is to have the same iC4 purity as the bottoms is to have nC4 purity. Consider purities from 90% to 99.99%. Discuss the results.
Answer Preview: The plot the external Rmin and Nmin = 0 at 100 0% iC4 purity. Since the butane component is a m…

, Chapter: 4 -Problem: 5 >> When a liquid and a vapor are in physical equilibrium, why is the vapor at its dew point and the liquid at its bubble point?
Answer Preview: The vapor at its dew point is the same temperature as the liqu…

, Chapter: 8 -Problem: 19 >> The extraction process shown Figure 8.47 is conducted without extract or raffinate reflux. Feed F' is composed of solvent and solute, and is an extract-phase feed. Feed F'' is composed of unextracted raffinate and solute and is a raffinate-phase feed. Derive the equations required to establish the three reference points needed to step off the stages in the extraction column. Show the graphical det
Answer Preview: To establish the three reference points needed to step off the stages in the answeion column shown …

, Chapter: 19 -Problem: 8 >> Use the design method suggested by Towler and Sinott [5] to design a vertical decanter to separate oil droplets suspended in water (the continuous phase). The design method suggests that an oil-droplet particle size, dp, of 150 mm be assumed; that the height of the decanter be increased by 10% to allow for a dispersion band at the oil/water interface (where the feed enters); that the velocity of t
Answer Preview: The design method is not unreasonable, exce…

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, Chapter: 14 -Problem: 13 >> Repeat Example 14.8 with the following changes: tube-side Reynolds number = 25,000; tube inside diameter = 0.4 cm; permeateside mass-transfer coefficient = 0.06 cm/s. How important is concentration polarization? Repeat Example 14.8 with the following changes: tube-side Reynolds number = 25,000; tube inside diameter = 0.4 cm; permeateside mass-transfer coefficient = 0.06 cm/

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