liquid extraction interdenominational, Study notes of Earth science

Download liquid extraction interdenominational and more Study notes Earth science in PDF only on Docsity! QUICE REVIEW INC. Room 608-610 Dona Amparo Bldg., G. Tolentino St. corner Espana Blvd, Sampaloc, Manila LEACHING: 1. A unit operation in which a soluble component is removed from an inert solid by a solvent which preferentially dissolves the soluble matter is known as a. adsorption c. leaching b. solvent extraction d. sedimentation 2. Which of the following is the most commonly used leaching solvent in vegetable oil industry? a. phenol c. furfural b. hexane d. liquid SO2 3. Which of the following does not involve leaching? a. dissolving gold from ores b. dissolving pharmaceutical products from bark or roots c. dissolving sugar from the cells of the beet d. removing nicotine from its water solution by kerosene 4. In case of constant underflow extraction operation, the _ at all solute concentration. a. solids are drained to the same extent b. ratio of the insoluble to solution is constant c. both (a) and (b) d. neither (a) nor (b) 5. With increase in temperature, the leaching rate increases because of the a. increased diffusivity. b. decreased viscosity of liquid. c. both (a) and (b) d. neither (a) nor (b) 6. Leaching of sugar from sugar beets is done using a. hot water c. dilute H2SO4 b. hexane d. lime water 7. The metal that is usually extracted from sea water is a. Calcium c. Potassium b. Sodium d. Magnesium 8. The unit operation by which soluble components of a liquid mixture are dissolved in a liquid immiscible with the insoluble component is a. absorption c. leaching b. adsorption d. solvent extraction 9. Tea percolation employs a. liquid-liquid extraction c. absorption b. leaching d. adsorption 10. In a determination of the solution retention data, the mass fraction of the solute in the extract was determined to be 0.6. The corresponding underflow analysis showed retention of 0.6 kg solvent per kg of inert solid. The mass fraction of solute in the underflow is most likely a. 0.600 c. 0.360 b. 0.225 d. 0.375 For numbers 12 to 13: In a salt recovery plant, rock salt is being leached to produce industrial salt in a continuous counter current system consisting of two ideal stages using water as leaching medium. the average composition of the rock salt is: inerts = 70%, soluble salts = 25%, moisture = 5%, all percentage by weight. The underflow from each stage contains 0.3 kg of solution per kg of inerts. The plant leaches 50 MT of rock salt per day using 50 MT of water. 11. The quantity of soluble salts recovered in MT/day is a. 12.1 c. 13.1 b. 14 d. 11.2 12. The composition of salt in weight percent in the final underflow is a. 0.89% c. 0.98% b. 0.78% d. 0.68% 13. A slurry of flaked soybeans weighing 100 kg contains 75 kg inert solids and 25 kg of solution with 10 wt% oil and 90 wt% solvent hexane. The slurry is contacted with 100 kg pure hexane in a single stage so that the value of retention for the outlet underflow is 1.5 kg of insoluble solid per kg solvent in the adhering solution. The composition of underflow leaving the extraction stage in percent by weight oil is a. 1.5 b. 2.3 c. 0.3 d. 0.8 14. Seeds, containing 20% by mass of oil, are extracted in a counter current plant, and 90% of the oil is recovered in a solution containing 50% by mass of oil. If the seeds are page 2 extracted with fresh solvent and 1 kg of solution is removed in the underflow in association with every 2 kg of insoluble matter, how many ideal stages are required? a. 5 c. 7 b. 3 d. 2 15. Powdered limestone (CaCO3) containing 10000 ppm NaOH is to be washed in a two-step continuous counter current washing system to remove most of the NaOH. Two cells and 100000 L of water per 10 MT/day of limestone fed are used. The slurry discharged and removed from the underflow contains 0.091 MT of water per MT CaCO3. Assuming complete mixing and washing, the NaOH content of the washed and dried limestone in ppm is a. 0.6 c. 0.8 b. 0.5 d. 0.4 For numbers 17 to 18: A counter current multiple contact extraction system is to treat 50 tons/hr of wet beets with fresh water as the solvent. The beets have the following analysis: Components Mass fraction water 0.48 pulp 0.40 sugar 0.12 The strong solution leaving the system is to contain 0.15 mass fraction sugar, 97% of the sugar in the sliced beets is to be recovered. Determine the number of extraction cells required, assuming equilibrium between the underflow and overflow in each cell. 16. If each ton of dry pulp retains 3 tons of solution. a. 16 c. 14 b. 15 d. 10 17. If each ton of dry pulp retains 3 tons of water. a. 16 c. 14 b. 15 d. 10 18. Roasted copper containing the ore as CuSO4 is to be extracted in a countercurrent stage extractor. Each hour, a charge consisting of 10 tons gangue, 1.2 tons CuSO4 and 0.5 ton water is to be treated. The strong solution produced is to consist of 90% water and 10% CuSO4 by weight. The recovery of CuSO4 is to be 98% of that in the ore. Pure water is to be used as fresh solvent. After each stage, one ton of inert gangue retained 2 tons water plus the copper sulfate dissolved in that water. Equilibrium is attained in each stage. The number of stages required is a. 12 c. 10 b. 8 d. 14 19. Tung meal containing 55% oil is to be extracted at a rate of 4000 kg/hr using n-hexane containing 5% wt oil as solvent. A counter current multiple stage extraction system is to be used. The meal retains 2 kg solvent per kg of oil free meal while the residual charge contains 0.11 kg per oil free meal while the product is composed of 15 weight percent of oil. The theoretical number of stages is a. 4 c. 3 b. 5 d. 6 20. The orebody of the Union Miniere du Haut-Katanga in the Belgian Congo is composed of malachite (CuCO3 Cu(OH)2) and gangue. Copper is extracted by crushing the ore to -20 mesh, agitating with a dilute solution of sulfuric acid, followed by multiple-contact countercurrent washing to wash the gangue free of the copper-bearing solution. The rich solution from the washing system is treated for removal of dissolved iron and aluminum and then sent to the electrolytic cells for precipitation of the copper. The dilute acid solution from the cells is recycled to the agitators for treatment of more raw ore. The counter current washing operation uses Dorr thickeners for the recovery of the rich solution. The slurry from the agitators, with the copper in the solution as copper sulphate, is fed to the thickeners at the rate of 300 tons per hour. According to operating records, the underflow from each thickener retains 1.22 tons of solution per ton of gangue, and the streams have the following compositions in mass percent. Feed to Thickener, % Strong Solution, % Underflow Leaving System, page 5 14. Equal quantity of chloroform and water is used is a. 10% c. 15% b. 20% d. 30% 15. Twice as much as chloroform as water is used a. 2.6% c. 3.5% b. 5.3% d. 6.0% 16. If extraction as in Problem 13 were followed by an extraction as in Problem 14 is a. 0.53% c. 0.63% b. 0.35% d. 0.73% 17. An aqueous solution containing 1.5 K mole X/ m3 is fed at 36 ml/s to the top of pat column of height 1.60 m and cross sectional area of 0.0045 m2 and it leaves at the bottom with 1.4 kmole/m3. An organic solvent, B, containing 0.008 K mole X/m3 flows counter to the aqueous phase at 9 ml/s. the equilibrium relationship is, Cxorganic = 0.3 Cxaqueous Determine: The log mean concentration difference for the transfer. a. 0.1625 kmol/m3 c. 0.178 kmol/m3 b. 0.182 kmol/m3 d. 0.194 kmol/m3 For numbers 18 to 19: Tests are made on the extraction of acetic acid from a dilute aqueous solution by means of a ketone in a small spray tower of diameter 46 mm and effective height of 1090 mm with the aqueous phase run into the top of the tower. The ketone enters free from acid at the rate of 0.0014 m3/sm2, and leaves with an acid concentration of 0.38 kmol/m3. The concentration in the aqueous phase falls from 1.19 to 0.82 kmol/m3. The equilibrium conditions are expressed by: Concentration of acid in ketone phase = 0.548 (Concentration of acid in aqueous phase). 18. Calculate the overall extraction coefficient based on the concentrations in the ketone phase. a. 0.00138/s c. 0.00425/s b. 0.00222/s d. 0.00397/s 19. Determine the height of the corresponding overall transfer unit. a. 1.53 m c. 1.02 m b. 1.17 m d. 1.49 m 20. A laboratory test is carried out into the extraction of acetic acid from dilute aqueous solution, by means of methyl iso-butyl ketone, using a spray tower of 47 mm diameter and 1080 mm high. The aqueous liquor is run into the top of the tower and the ketone enters at the bottom. The ketone enters at the rate of 0.0022 m3/sm2 of tower cross-section. It contains no acetic acid, and leaves with a concentration of 0.21 kmol/m3. The aqueous phase flows at the rate of 0.0013 m3/sm2 of tower cross-section, and enters containing 0.68 kmol acid/m3. What is the corresponding value of the overall HTU, based on the ketone phase? Using units of kmol/m3, the equilibrium relationship under these conditions may be taken as: Concentration of acid in the ketone phase = 0.548 (Concentration in the aqueous phase). a. 1.75 m c. 1.94 m b. 1.81 m d. 1.63 m ADDITIONAL PROBLEMS 1. A liquid mixture of acetaldehyde and toluene contains 8 lb of acetaldehyde and 90 lb of toluene. Part of the acetaldehyde in this solution is to be extracted using pure water as the extracting agent. The extraction is to be performed in two stages, using 25 lb of fresh water for each stage. The raffinate layer from the first stage is treated by fresh water in the second stage. The extraction takes place at 170C and the equilibrium equation is Y=2.2X may be employed. Assuming toluene and water is immiscible, what would be the weight percent of acetaldehyde in a mixture of the extracts from both stages if each of the extractions were theoretically perfect? ANSWER: 8.96% 2. In order to extract acetic acid from a dilute aqueous solution with isopropyl ether, the two immiscible phases are passed counter currently through a packed column 3 m in length and 75 mm in diameter. It is found that if 0.5 kg/m2 of the pure ether is used to extract 0.25 kg/m2s of 4.0 percent acid by mass, then the ether phase leaves the column with a concentration of 1.0 per cent acid by mass. Calculate: (a) the number of overall transfer units, based on the raffinate phase, and (b) the overall extraction coefficient, based on the raffinate phase. The page 6 equilibrium relationship is given by: (kg acid/kg isopropyl ether) = 0.3 (kg acid/kg water). ANSWER: KRa = 0.461 kg/m3-s and HOR = 5.33 3. In the extraction of acetic acid from an aqueous solution with benzene in a packed column of height 1.4 m and of cross sectional area of 0.0045 m2. Determine the overall transfer coefficient and the height of the transfer unit. Acid concentration in inlet water phase = 0.690 kmol/m3 Acid concentration in outlet water phase = 0.685 kmol/m3 Flowrate of benzene phase =1.27 x10-3 m3/m2-s Inlet benzene phase concentration = 0.0040 kmol/m3 Outlet benzene phase concentration = 0.0115 kmol/m3 The equilibrium relationship for this system is: C*B/C*W=0.0247 ANS: KBa = 7.8x10-4 kmol/s-m3 and HOB = 1.63 m DISTILLATION: 1. The physical separation of components in a miscible mixture by simultaneous evaporation and condensation is a. absorption c. extraction b. drying d. distillation 2. The ease of difficulty of separating components by distillation is determined by the a. relative volatility b. mole fraction c. viscosity d. weight fraction of the components 3. The distillation process involves a. momentum transfer c. heat transfer b. mass transfer d. heat and mass transfer 4. In a batch distillation, the boiling point of the distillate product compared to the residue is a. the same c. lower b. higher d. half 5. When the relative volatility of two miscible components is close to 1.00, the components can be separated by a. simple rectification c. extractive distillation b. batch distillation d. flash distillation 6. Increasing the operating pressure of a distilling column a. does not make a difference in components separation b. makes separation difficult c. sharpens separation d. requires less heat in the feed heater 7. Strictly speaking, the relative volatility of most ideal binary solution is a. not affected by temperature b. greatly affected by temperature c. slightly affected by temperature d. greatly affected by pressure 8. Using the Antoine’s Equation, the vapor pressure of tetrahydrofuran at 800 C is estimated to be a. 2000 torrs c. 1173 torrs b. 1518torrs d. 2562 torrs 9. For a mass transfer to take place, there must be a. concentration gradient b. more than two components involved c. heat present d. enthalpy change 10. Calculate the equilibrium compositions of the liquid and the vapor phases for the mixture of methyl alcohol in water at a temperature of 500C and under a pressure of 40 kPa. Assume that both the liquid and the vapor behave ideally. At 500C, the vapor pressure of methyl alcohol is 53.32 kPa and that of water is 12.33 kPa. ANS: Liquid: 67.5% methyl alcohol Vapor: 89.98% methyl alcohol 11. Determine the composition of the equilibrium vapor over a liquid mixture consisting of 10 mol % water, 50 mol % acetic acid and 40 mol % acetone at 800C, assuming that the component obey Raoult`s law. The vapor pressures of components at 800C are: water – 47.33 kPa, acetic acid – 27.32 kPa and acetone – 219.77 kPa. ANS: 4.45% water, 12.85% acetic acid and 82.70% 12. A liquid mixture of ethyl alcohol and water is in equilibrium with a vapor containing ethyl alcohol and water at a total pressure of 760 mmHg. A sample of the vapor indicates that it page 7 contains 3.3 mol of ethyl alcohol for every 1.7 mol of water. If the liquid has a mol fraction of 0.52 ethyl, what is the relative volatility for the mixture? a.1.59 c. 1.69 b.1.79 d. 1.89 13. An equimolal mixture of benzene and toluene is subjected to a simple batch distillation at atmospheric pressure. For the purpose of this problem, assume α = 2.55. a. If the distillation is discontinued when the mols of distillate amount to 60% of the mols charged, calculate: (i) the concentration of the distillate, (ii) the concentration of the liquid left in the still and (iii) the amount of benzene in the distillate, expressed as percentage of the amount of benzene in the charge. ANSWER: (i) 63.9% benzene (ii) 70.8% toluene (iii) 76.6% b. If the distillation be discontinued when 60% of the original is in the distillate, calculate: (i) the concentration of the distillate, (ii) the concentration of the liquid left in the still and (iii) the mols of distillate, expressed as percentage of the mols of the charge. ANSWER: (i) 66.6% benzene (ii) 63.6% toluene (iii) 45.1% 14. In distillation, the cooled liquid stream returned to the column to a cool plate or stage is called a. reboil c. feed b. reflux d. bottoms 15. In a distilling column, the highest pressure will be at a. the top b. the bottom c. the feed plate d. between the feed plate and the top 16. A heat transfer equipment to convert vapor to liquid is a/an a. evaporator c. condenser b. reboiler d. still 17. A binary mixture of two moles benzene and 8 moles of toluene will boil at a. 110 0C c. 110 0F b.105 0C d. 102 0C 18. A reboiler provides heat to the a. top c. the feed b. the intermediate reflux d. the bottom of a distilling column 19. The temperature in distilling column, from bottom to top a. increases b. maximum c. decreases d. between minimum & maximum 20. A 50 % by weight benzene – toluene mixture is fed to a column at 180 0F and 1 atm. The condition of the feed is called a. saturated liquid c. saturated vapor b. sub cooled liquid d. mixture of liquid and vapor 21. The theoretical minimum reflux ratio in distillation column is attained if the column has a. 1 plate c. 100 plates b. 10 plates d. infinite number of plates 22. The theoretical minimum reflux ratio in a distillation column is reached if the column has a. 1 plate c. 100 plates b. 10 plates d. an infinite number of plates 23. The percentage change in the boiling point of a 20 mole benzene – toluene solution when the pressure is increased from 1 atm to 2 atm is a. 10.5 % increase c. 25.5 % decrease b. 25.5 % increase d. 10.5% decrease 24. A distillation column separates 10000 kg/hr of a benzene-toluene mixture as shown in the figure below. In the figure xF, xD and xW represent the weight fraction of benzene in the feed, distillate and residue respectively. The reflux ratio is a. 0.5 c. 0.6 b. 1.0 d. 2.0 page 10 b. the liquid flow rate is smaller c. the gas flow rate is larger d. the gas flow rate is smaller 10. In an air-water contact operation, when the temperature and humidity of the air both decrease the process is a. dehumidification c. non-adiabatic humidification b. adiabatic humidification d. water cooling 11. The relative humidity of unsaturated air-water vapor mixture is always a. equal c. less than b. greater than d. can not be determined 12. 1000 cfm of air (A) at 950F dry bulb, 740F wet bulb is mixed with 2000 cfm of air (B) at 650F dry bulb, 540F wet bulb. Determine for the mixed stream: dry bulb temperature, wet bulb temperature and cfm of mixed stream. ANSWER: Tdb = 74.70F, Twb = 610F and Q = 3014 cfm 13. An adiabatic humidifier operates at atmospheric pressure under such conditions that the air leaving the unit is saturated at the adiabatic saturation temperature. If the air enters the humidifier at 800F with a humidity of 0.05 lb of H2O per lb dry air, what will be the humidity of the air leaving the unit? a. . 0.03 c. 0.018 b. 0.010 d. 0.028 14. If 100 lb of dry air at 500F db and 500F wb is mixed with 300 lb of dry air at 1100F db and 800F wb, the resulting mixture will have a dry bulb temperature of a. 800F c. 850F b. 900F d. 950F 15. What is the wet bulb temperature of the resulting mixture for the mixed air of Problem 13? a. 850F c. 650F b. 750F d. 700F For numbers 15 to 17: The air in a theater 120 by 70 by 40 ft is to be changed every 10 minutes and it is to be supplied at 700F and 50% RH. The extreme summer condition of the air outside is 950F and 70% RH. It is planned to cool and dehumidify this air to the desired humidity by the use of coke packed tower. The air will leave the tower saturated and is to be reheated to the desired temperature before being blown into the theatre. Cooling water is available at 450F. Data: UGa = 150; L/S = 1150 and w/S = 1200. 16. What should be the height of the tower? a. 7.85 ft c. 9.12 ft b. 6.27 ft d. 8.08 ft 17. Calculate the diameter of the tower. a. 15.7 ft c. 11.2 ft b. 12.6 ft d. 17.9 ft 18. To what temperature is the air cooled in the tower? a. 510F c. 720F b. 640F d. 800F For numbers 19 to 23: 20000 cfm of air are to be cooled from 900 to 720F, by the use of a horizontal-spray type humidifier, employing a counter flow of air and water. The air has an initial humidity of 0.011 lb of water vapor per lb of dry air. The unevaporated water collects inside the apparatus, to be recirculated to the spray nozzles, and make-up water at 700F, is fed to the pump. The spray chamber will operate substantially adiabatically, and normal barometric pressure prevails within the apparatus. When spraying 1200 lb of water/hr-ft2 of cross section of the spray chamber and employing an air rate of 2400 lb of dry air/hr-ft2 of cross section, test data show that overall coefficient of heat transfer UGa is 90 BTU/hr-0F mean difference-ft3 of spray chamber. Based on the data given, calculate: 19. Cross section of spray chamber, in sq ft a. 43.7 sq ft c. 51.6 sq ft b. 35.5 sq ft d. 64.8 sq ft 20. Pounds of water sprayed per hour a. 42600 lb/hr c. 48400 lb/hr b. 40100 lb/hr d. 46400 lb/hr 21. Pounds of make-up water required per hour a. 225 lb/hr c. 341 lb/hr b. 410 lb/hr d. 167 lb/hr 22. Length of spray chamber, in ft a. 12 ft c. 9 ft b. 17 ft d. 15 ft 23. Humidity of air leaving the chamber, as lb of water vapor/lb of dry air a. 0.018 c. 0.011 page 11 b. 0.015 d. 0.012 For numbers 24 to 25: The following data were obtained from a test on a forced-draft cooling tower: Water entering per min 640 gpm Temperature of water entering 109.90F Temperature of leaving water 90.50F Humidity of entering air 0.012 Humidity of leaving air 0.031 Temperature of entering air 830F Temperature of leaving air 950F Volume of tower 2200 ft3 24. Find the ft3 of air entering the tower per minute. a. 59500 cfm c. 62800 cfm b. 45100 cfm d. 71900 cfm 25. Find the value of the coefficient UGain BTU/ft3-hr-0F. a. 19.5 c. 26.2 b. 47.1 d. 33.2 ADDITIONAL PROBLEMS 1. It is desired to design a coke-packed dehumidifier to cool 2000 ft3 of saturated air/min from 130 to 650F. The operation is to be conducted at normal barometric pressure. Cooling water is available at 550F and will be permitted to rise to 1100F. It is agreed to use a gas velocity of 12000 lb of dry air/hr-ft2 of total cross section. UGa = 250 BTU/hr-0F mean difference-ft3 of spray chamber. Calculate to the height and diameter of the tower required and the weight of cooling water per hour. ANSWER: D = 2.71 ft, z = 6 ft and L = 15800 lb/hr 2. A water cooling system installed to cool 650 gpm to 870F gives the following data: Temperature of entering water 1090F Temperature of leaving water 870F The air enters with a dry bulb of 750F and at 60%RH and a total pressure of 29.5 psia. The exit air is at 960F and 100%RH. Calculate the volume of air entering and the percentage of water evaporated based on the total amount of water entering the tower. ANSWER: 27000000 cfh and 1.48% DRYING 1. The vapor pressure exerted by the moisture contained in a wet solid depends upon the a. nature of the moisture c. temperature b. nature of the solid d. all a, b, and c 2. To remove all the moisture from a wet solid requires exposure to a. perfectly dry air c. highly humid air b. air at high temperature d. none of these 1. Milk is dried usually in a a. freeze dryer c. spray dryer b. tray dryer d. rotary dryer 2. Equilibrium-moisture curves of different solids a. are different b. are same c. depend on the humidity of the gas d. none of these 3. Detergent solution is dried to a powder in a a. spray dryer c. spouted bed dryer b. tunnel dryer d. pan open to atmosphere. 4. In paper industry, paper is dried in a. tunnel dryer c. heated cylinder dryer b. conveyor dryer d. festoon dryer 5. Moisture content of a substance when at equilibrium with a given partial pressure of the vapor is called a. free moisture c. unbound moisture b. equilibrium moisture d. bound moisture 6. Calcium ammonium nitrate (a fertilizer) is dried in a a. rotary dryer c. vacuum dryer b. tunnel dryer d. none of these 7. Moisture in a substance exerting an equilibrium vapor pressure less than that of pure liquid at at the same temperature is a. bound moisture c. unbound moisture b. critical moisture d. none of these 8. Drying of a solid involves page 12 a. only heat transfer b only mass transfer c. both heat and mass transfer d. none of these 9. Rotary dryer cannot handle a. free flowing materials c. dry materials b. sticky materials d. granular materials 10. Sticky material can be dried in a a. tray dryer c. rotary dryer b. fluidized bed dryer d. none of these 11. Moisture in a solid exerting an equilibrium vapor pressure equal to that of the pure liquid at the same temperature is a. unbound moisture c. critical moisture b. free moisture d. bound moisture 12. Refractory bricks are usually dried in a a. tray dryer c. tunnel dryer b. conveyor dryer d. festoon dryer 13. Heat sensitive materials like certain pharmaceuticals and food stuff can be dried a. in indirect tray dryer c. in spray dryer b. by freeze drying d. none of these 14. Moisture contained by a substance in excess of the equilibrium moisture is called a. unbound moisture c. free moisture b. critical moisture d. bound moisture 15. In the constant rate period of the rate of drying curve for batch drying a. cracks develop on the surface of the solid b. rate of drying decreases abruptly c. surface evaporation of unbound moisture occurs d. none of these 16. Dryer widely used in a textile industry is a. cylinder dryer c. conveyor dryer b. tunnel dryer d. festoon dryer 17. A solid material shows case hardening properties while drying. Which of the following should be controlled to control the drying process? a. flow rate of inlet air b. relative humidity of outlet air c. humidity of inlet air d. temperature of the solid 18. Air at a particular humidity is heated in a furnace. The new dew point a. decreases b. increases c. depends on the extent of heating d. remains unchanged 19. The critical moisture content in case of drying indicates a. beginning of falling rate period b. beginning of constant rate period c. end of falling rate period d. none of these 20. A slurry is to be dried to produce flaky solid. Which dryer would you recommend? a. spray dryer c. drum dryer b. rotary dryer d. dielectric dryer 21. For continuous drying of granular or crystalline material, the dryer used is a. tunnel c. tray b. rotary d. none of these 22. All moisture in a non-hygroscopic material is __ moisture a. free c. equilibrium b. unbound d. bound 23. During constant rate period, the rate of drying decreases with a. decrease in air temperature b. increased air humidity c. both a and b d. neither a nor b For numbers 26 to 27: Wet leather enters a continuous drier at 45% moisture (wet) and leaves at a rate of 200 lb/h with a moisture content of 25% moisture (dry). Air at 1400F and 10% RH enters the drier, and leaves the drier at 1200F and 40% RH. Assume atmospheric pressure on both inlet and outlet. Vapor pressures of water at 1200F and 1400F are 87.55 mmHg and 149 mmHg, respectively. 24. Calculate the rate (lb/h) at which water is removed from the leather a. 91 c. 186 b. 182 d. 291 25. Calculate the volumetric flow rate of air (ft3/hr)