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Q1: Ansell Inc. produces chemical-resistant gloves. Their chemicalpermeation test cell is shown in the illustration to the right. Theglove material is used as a thin membrane separating a liquidcompartment from a gas compartment. Nitrogen gas iscontinuously pumped through the gas side of the chamber to keepthe concentration of liquid vapor that has diffused across themembrane close to zero. Their test liquid is epichlorohydrin, a chemical we have used inour lab to crosslink polymers. According to Ansell, gloves made ofa neoprene-natural rubber blend (0.67 mm thick, density of 1.18g/cm3) are rated as "Good" in terms of permeation rate, whichmeans that the steady state permeation rate is no more than 90ug/cm2-min (or 1.6 x 10-8 mol/cm2-s).(E a) A typical value of a diffusion coefficient of a small organic molecule in a polymer is 5 x 10-7 cm2/s. Calculate thepartition coefficient HA of epichlorohydrin in neoprene-natural rubber using this value of DAB. b) Diffusion coefficients of molecules in most polymers are much higher than in other solids. Hence manipulation of HAlsa promising way to reduce permeation rates in polymeric gloves. Does the value of Ha found in part a) suggest that Ansell has successfully developed a material that will do a “good" jobof protecting your hands from epichlorohydrin? Explain your reasoning briefly. c) Sketch the steady-state molar concentration profile of epichlorohydrin in the neoprene rubber from the liquid phase,through the rubber and into the gas phase. That is, sketch the mass transfer equivalent of WRF Fig 16.2 for steady-state heat conduction as shown below. Only a qualitatively reasonable sketch is expected (no calculations are necessary), but draw it in terms of molarconcentration for each phase (liquid/solid/gas). Note that the density of the liquid and rubber phases are equal. See Answer
Q2:P7.43 10 L of water are contaminated with 200 mmol phe- nol. The water must be cleaned up to contain no more than 5 mmol phenol before it can be discharged. This will be accomplished by pumping the solution into a vessel loaded with fresh activated carbon, waiting for the phases to equilibrate, then removing the liquid solution. How much activated carbon should be loaded into the vessel? Assume an operating tempera- ture of 20°C. Use the equilibrium data given with Prob. P7.42.See Answer
Q3:Chapter Thirteen Gas Absorption 13.2 An absorption column is to be designed to recover 99.5% of the NH3 from a feed stream, which is supplied at 72 °F and an NH3 partial pressure of 10 mm Hg. The feed stream contains 2100 lb/hr of air. The column operates at 1.0 atm, is supplied with pure water at 72 °F that flows at 1.5 times the minimum water rate. Hoy for the operation is 1.9 ft. a. Find the minimum water rate, in lb/hr. b. Find the height of the packing required if = 1.0.See Answer
Q4:13.3 A gas stream containing a valuable hydrocarbon (MW = 44) is scrubbed with a nonvolatile oil (MW=300, specific gravity = 0.90) in a tower packed with 1-inch Raschig rings. The entering gas analyzes 20 mole percent hydrocarbon with the remainder being an inert gas (MW = 29). The gas stream enters the column at 5000 lb/hr-ft2, and hydrocarbon-free oil enters the top at 10,000 lb/hr-ft. The column is 4 ft in diameter. Ninety-five percent of the valuable hydrocarbon is to be recovered. Use the equilibrium relationship and the equations for k,a and ka given below. Estimate the height of packing required.See Answer
Q5:13.4 An air-ammonia mixture, containing 1.5 volume percent NH3, at 95 °F and 1.0 atm is scrubbed in a packed tower with pure water at 95 °F. The outlet NH3 concentration must be no more than 0.1% to meet EPA regulations. a. What volume of this gas in acfm can be processed in a 2-ft diameter column packed with 1-in. ceramic Raschig rings if the gas-to-liquid mass flow ratio is 1.0? b. What height of packing is necessary if Hoy is 1.85 ft?See Answer
Q6:given dry bulb temperature is 35c wet bulb temperature is 27c to find with use of the provided psychrometric chart fig 1See Answer
Q7:given thick wall natural rubber pipe with outer diameter 40mm and inner diameter 32mm is in use for transport of 100 co _zu5dBoiASee Answer
Q8:1. Multistage Distillation Separation and VLE Consider the VLE conditions for a binary mixture of 2-propanol and 2-butanol. This process has a feed flow rate of 600 mol/s, where the feed enters as a mixture of vapor (110 mol V in feed) and liquid (490 mol L in feed), and an initial feed concentration of 65% 2-propanol and 2-butanol. The reflux ratio is given as R = 1, and a target top concentration of 98% 2- propanol and a bottoms concentration of 12% 2-propanol. a. Draw a PFD for this process. Construct xy-, Txy, and Pxy diagrams for this system, assuming either a constant T = 80 °C or a constant P = 760 mmHg. Reference Antoine's coefficients from the Table provided with HW2. b. Solve for the distillate and bottoms flow rates. c. Assume that the ratio of streams in the rectifying section of the column are defined by L/V = 0.5, while streams in the stripping section of the column are defined by L'/V' = 2.6, where the vapor returning to the column following the partial reboiler and V':B split is 50 mol/s (V"). Graphically determine the theoretical number of stages required by plotting this information on an x-y plot, including the q-line, TOL, and BOL d. Calculate the heat duty for the condenser (total) and reboiler (partial), assuming no heat loss (Que="0). The heat of vaporization for 2-propanol is ~39.85 kJ/mol and for 2-butanol is ~40.8 kJ/mol.See Answer
Q9:2. For this same binary separation (Part 1), prepare 3 graphically-solved/constructed McCabe Thiele Diagrams derivations, varying 3 specific specifications and solving for new flow rates or compositions (i.e., change ZF, R, and Target Purity). (note: you will likely be able to use a similar spreadsheet). Briefly discuss how each change affected the process (positively or negatively!).See Answer
Q10:1. Explain with schematic drawing the mechanisms of mass transfer. 2. What are the possible driving forces for mass transfer. 3. Explain Fick's Law. 4. Define each terms what they are and their units in SI of the following equation:See Answer
Q11:Example Estimate the diffusivity of ethanol (C,H,O) in a dilute solution in water at 288 K. Compare your estimate with the experimental value reported in Appendix A. (1.0*10^-5 cm²/s) V=167.1 cm³/molSee Answer
Q12:Absorption A combustion gas (22 kmol) from a large coal-fired power plants contains carbon dioxide 11.5 + a+f-d = _CO₂ (mol %) the rest is air. We want to remove a+f-d CO₂ (mol %). 80 50 " the CO₂ so that the cleaned gas contains 1.1+ This is done by contacting the combustion gas with a water-amine solution in a plate absorption column at about 60°C and 1.2 bar. The water-amine feed solution contains 1.0% CO₂ and the enriched solution leaving the bottom contain 5.32+3= % CO₂ The vapor liquid equilibrium relation is given by, y = 0.84x. Assume constant molar flows calculate the liquid flow rate and required number of plates. 103 = =See Answer
Q13:Q3. Choose a single answer. Show steps. The diffusivity of Argon in No at 20 °C and 1 atm pressure is 0.194 cm³/s. What would you expect the diffusivity of N: in Ar to be at 50 °C and 2.5 atm? Use the Chapman correlation. Does increasing the temperature or increasing the pressure have more effect on the diffusivity? Please comment A) 0.194 cm³/s B) 0.442 cm³/s C) 0.5 cm³/s D) 0.535 cm³/s E) 0.555 m³/s F) 0.535 m³/s G) 0.442 m³/s H) 0.09 cm³/s ) 0.09 m²/sSee Answer
Q14:Q1. Mass Transfer coefficient relationships The gas-phase mass transfer coefficient for the evaporation of a drop of ethyl alcohol in a stream of air at 300 K and 1.2 bar pressure is kg = 2.4 x 10-6 kmol/(s.m² (mm Hg)). Calculate values of mass transfer coefficient if the driving force is expressed in terms of difference in: (i) mole fraction of alcohol in the gas phase; (ii) mole fraction of alcohol; (iii) concentration of alcohol in kmol/m³. If the diffusivity of alcohol in air is 0.102 cm²/s at 1 atm and 0 C, estimate the thickness of the gas film. Vapor pressure of alcohol = 0.0877 bar at 300 K.See Answer
Q15:2. Mass and energy balances around a multistage distillation column A mixture that contains 46 wt% acetone (CH3COCH3), 27% acetic acid (CH3COOH), and 27% acetic anhydride [(CH3CO)20] is distilled at P=1 atm. The feed enters the distillation column at 348 K at a rate of 15,000 kg/h. The distillate (overhead product) is essentially pure acetone, and the bottoms product contains 1% of the acetone in the feed. The vapor effluent from the top of the column enters a condenser at 329 K and emerges as a liquid at 303 K. Half of the condensate is withdrawn as the overhead (distillate) product, and the remainder is refluxed back to the column. The liquid leaving the bottom of the column goes into a steam-heated reboiler, in which it is partially vaporized. The vapor leaving the reboiler is returned to the column at a temperature of 398 K, and the residual liquid, also at 398 K, constitutes the bottoms product. A flowchart of the process and thermodynamic data for the process materials follow.See Answer
Q16:4) WRF 26.3: Hollow cylinder drug delivery system Learning Objective: Simplify the generalized species equation of continuity to solve a mass transfer problem in a cylindrical coordinate system. 26.3 Consider the hollow cylinder for drug delivery release shown in the figure below. The hollow center contains a lump of solid solute A (drug) in a liquid. Solute A dissolves in the liquid to a maximum concentration CA* = 0.05 mmole A/cm³ and then diffuses radially through the gel layer to the surrounding liquid, which is maintained at a constant concentration, CA∞ = 0.01 mmole A/cm³. In the present system, the effective diffusion coefficient of solute A in the gel layer is De = 1.2 x 105 cm²/s, the thickness of the gel layer (R, -R) is 0.50 cm, the length is 1.5 cm, and the outer radius (R) is 0.75 cm. You may assume that the concentrations of solute A are dilute, the liquid within the hollow portion of the cylinder has constant concentration of CA*, and the edges of the cylinder are sealed. As long as the solid solute A inside the hollow cylinder has not completely dissolved away, the mass transfer process has a constant source and a constant sink with respect to solute A. a. What are reasonable boundary conditions for the mass transfer? b. What are reasonable assumptions for the mass transfer process? c. Estimate the total transfer rate of solute A exiting cylinder atr= Ro, WA, in units of mmole A/s. As part of your analysis, state the appropriately-simplified differential forms of the Flux Equa- tion and the General Differential Equation for Mass Transfer. d. Based on your result for part (c), if the initial loading of solid solute A within the hollow center is mA = 0.20 mmole A, and the liquid within the hollow center is always at concen- tration CA*, how many hours will it take for the solid A to be completely dissolved? L = 1.5 cm Sealed ends DA 1.2 x 105 cm²/s CA = 0.05 mmole/cm³ Solid Gel layer CA =0.01 mmole/cm³ solute A I (0.2 mmol)! DAe ICA' CA r = Ro r=0 r R (0.75 cm) (0.25 cm) Solution hints for part c: Start by simplifying WRF Eq. 25-11 and show/explain these steps: 0-("N-) dr By continuity NR=NA NA constant along Then substitute Fick's law (noting that convective velocity can be neglected) and integrateSee Answer
Q17: • • To complete this assignment follow the instructions Handwritten on A4 unruled sheets and later uploaded in pdf format Any answers must not be copied from any source Plag of any kind is not acceptable once detected by us • Provide detailed explanation for positive ratings and feedback Question 1 I. (25 pts) We wish to separate a mixture of 30 mol% n-butane and 70% n-hexane in a flash drum operating with Y = = = 0.4 and temperature 100 °C. The feed rate is 10 kmol/h. Determine Pdrum, Xi, and yi. (Note: the vapor pressures of n-butane and n-hexane at 100 °C are 11121.2 mmHg and 1844.4 mmHg, respectively).See Answer
Q18:Problem: A stage extraction process is depicted in Fig. P12.9. In such systems, a stream containing a weight fraction Yin of a chemical enters from the left at a mass flow rate of F1. Simultaneously, a solvent carrying a weight fraction Xin of the same chemical enters from the right at a flow rate of F2. Thus, for stage i, a mass balance can be represented as F₁Yi-1+ F2X+1 = F₁Yi + F₂Xi (P12.9.1) At each stage, an equilibrium is assumed to be established between Y, and Xi as in K Yi (P12.9.2) where K is called a distribution coefficient. Equation (P12.9.2) can be solved for X, and the result substituted into Eq. (P12.9.1) to yield Yi-1 − (1 + ½² K) Y + (¾½²K) Yi+1 = 0 - (P12.9.3) If F₁ = 400 kg/h, Yin = 0.1, F2 = 800 kg/h, Xin = 0, and K = 0.2, determine the values of Yout and Xout using 1 to 15 stages and plot them vs the number of stages. Note that Eq. (P12.9.3) must be modified to account for the inflow weight fractions when applied to the first and last stages.See Answer
Q19:1. In a gas-phase diffusion mass-transfer process, the steady-state flux of species A in a binary mixture of A and B is 5.0 x 10-5 kgmole A/m²s, and the flux of B is 0 (zero). At the particular point in the diffusion space, the concentration of species A is 0.005 kgmole/m³ and the concentration of species B is 0.036 kgmole/m³. Estimate the individual net velocities of species A and B along the direction of the mass transfer, and the average molar velocity.See Answer
Q20:3. A hemispherical droplet of liquid water, lying on a flat surface, evaporates by molecular diffusion through still air surrounding the droplet. The droplet initially has a radius R. As the liquid water slowly evaporates, the droplet shrinks slowly with time, but the flux of the water vapor is a nominal steady state. The temperature of the droplet and the surrounding still air are kept constant. The air contains water vapor of fixed concentration at an infinitely long distance from the droplet's surface. • Draw a picture of the physical process, • Select a coordinate system that will best describe this diffusion process, • List at least five reasonable assumptions for the mass-transfer aspects of the water- evaporation process, • Simplify the general differential equation for mass-transfer in terms of the flux NA. • Specify the simplified differential form of Fick's flux equation for water vapor (species A) • Identify the proper boundary conditions, • Write down the differential equation for CA-See Answer

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