Questions and Answers of Analysis Synthesis And Design Of Chemical Processes

For fully developed turbulent flow, assuming all variables not mentioned are held constant:What is the effect of doubling the flowrate on the pressure drop?What is the effect of increasing the pipe
For a reduction in naphthalene feed by 50%, determine the pressures and flows of all streams after the scale-down.
Consider the situation depicted in Figure P19.23. The fluid is an oil with a specific gravity of 0.85. Fill in the missing data in Table P19.23. 1 2 Figure P19.23 Table P19.23 Stream
Repeat Problem 19.21 for laminar flow.Problem 19.21For fully developed turbulent flow, assuming all variables not mentioned are held constant:What is the effect of doubling the flowrate on the
For water flowing in the situation shown in Figure P19.24 and the data in Table P19.24, do the following:Calculate the mass flowrate of Stream 3.Calculate the velocity of Stream 4.What schedule-40
Consider the situation depicted in Figure P19.25. The liquid level in the cylindrical tank is increasing at 0.02 ft/sec.What is the net rate of flow into the tank?What is the velocity in the 3-in
Water is pumped through a 750-ft length of 6-in, schedule-40 pipe. The discharge at the end of the pipe is 50 ft above the suction end. The pump is 80% efficient and is driven by a 20 hp motor. If
A hydroelectric power plant takes 25 m3/s of water from a large reservoir through its turbine and discharges it to the atmosphere at 1 m/s. The turbine is 50 m below the reservoir surface. The
Water is pumped at a constant rate of 10 m /h from an open tank on the floor to an open tank with a level 10 m above the floor. Frictional losses in the 50-mm-diameter pipe between the tanks are 3.5
Water in a dam on a 75-ft-deep river is passed through a turbine to produce energy. The outlet of the turbine is 15 ft above the river bed. The mass flowrate of water is 65,000 lb/s, and the inside
Many potential drugs have low water solubility, hindering their transport in the body’s aqueous material distribution medium (blood). One way to improve solubility is to decrease particle size
A pump operating at 80% efficiency delivers 30 gal/min of water from a reservoir to an open-air storage tank at a chemical plant 1 mi away. A 3-in, schedule-40 pipe is used, and the frictional losses
pressurized tank situated above ground level contains a liquid with specific gravity of 0.9. The liquid flows down to ground level through 4-in, schedule-40 pipe through a pump (75% efficiency) and
Water is pumped from one storage tank to a higher tank at a steady rate of 10-3 m3 /s. The difference in the elevations of the two water tanks is 50 m. The storage tank, which serves a source, is
Oil (SG = 0.88) flows at 5 ft /s from one tank, through a pump, to another tank. The pipe diameter between the source tank and the pump is 12 in, and the pipe diameter between the pump and the
Consider the problem of how long it takes for a tank to drain. Consider an open-top cylindrical tank with one horizontal exit pipe at the bottom of the tank that discharges to the atmosphere. The
A fluid with specific gravity of 0.8 is in a tank, at a pressure of 150 kPa, with a level maintained at 5 m above ground level.The fluid leaves the tank through 4-in, schedule-40 pipe (frictional
The following equations describe a fluid-flow system. Draw and label the system. m₁ + m₂ = m3 = m4 0²-0² + - nW₁ = 0 2 Ps-P4+g (25-2₁) + ef = 0 2 P4-P3 P P
The following equations describe a fluid flow system, with friction neglected. Draw and label the system, making sure that your diagram is visually accurate. m3 + m₂ = m₁ = m5 P₂-P₁ P +9
An aneurysm is a weakening of the walls of an artery causing a ballooning of the arterial wall. The result is a region of larger diameter than a normal artery. If the “balloon” ruptures in a
A pipeline is replaced by new 2-in, schedule-40, commercial-steel pipe. What power would be required to pump water at a rate of 100 gpm through 6000 ft of this pipe?
Hot water at 43°C flows from a constant-level tank through 2-in, schedule-40, commercial-steel pipe, from which it emerges 12.2 m below the level in the tank. The equivalent length of the piping
Crude oil (μ = 40 cP, SG = 0.87) is to be pumped from a storage tank to a refinery through a series of pump stations via 10- in, schedule-20, commercial-steel pipeline at a flowrate of 2000 gpm. The
A pipeline to carry 1 million bbl/day of crude oil (1 bbl = 42 gal, SG = 0.9, μ = 25 cP) is constructed with 50-in-insidediameter, commercial-steel pipe and is 700 mi long. The source and
A pump draws a solution of specific gravity 1.2 with the viscosity of water from a ground-level storage tank at 50 psia through 3.5-in, schedule-40, commercial-steel pipe at a rate of 12 lb/s. The
Many chemical plants store fuel oil in a “tank farm” on the outskirts of the plant. To prevent an environmental disaster, there are specific rules regarding the design of such facilities. One
Consider a two-pipes-in-series system: that is, Pipe 1 is followed by Pipe 2. The liquid is water at room temperature with a mass flowrate of 2 kg/s. The pipes are horizontal. Calculate the pressure
Two parallel sections of pipe branch from the same split point. Both branches end at the same pressure and the same elevation. Branch 1 is 3-in, schedule-40, commercial-steel pipe and has an
Assume that the same two pipes in Problem 19.47 are now in parallel with the same total pressure drop. Compute the mass flowrate in each section of pipe. Neglect additional frictional losses due to
A pipe system to pump #6 fuel oil (μ = 0.8 kg/m s, ρ = 999.5 kg/m3) consists of 50 m of 8-in, schedule-40, commercial-steel pipe. It has been observed that the pressure drop is 8.79 × 104
There are three equal-length sections of identical 3-in, schedule-40, commercial-steel pipe in series. An increased flowrate of 20% is needed. How is the pressure drop affected? It is decided to
Consider two parallel arteries of the same length, both fed by a main artery. The flowrate in the main artery is 10 m /s. One branch is stenotic (has plaque build-up due to too many Big Macs, Double
One of the potential benefits of the production of shale gas is that certain seams of the gas contain significant amounts of ethane, which can be cracked into ethylene, a building block for many
Natural gas (methane, μ = 10-5 kg/m s) must flow in a pipeline between compression stations. The compressor inlet pressure is 250 kPa, and its outlet pressure is 1000 kPa. Assume isothermal flow at
Your plant produces ethylene at 6 atm and 60°F. It is to be delivered to a neighboring plant 5 miles away via pipeline, and the pressure at the neighboring plant entrance must be 2 atm. The
Calculate the terminal velocity of a 2 mm diameter lead sphere (SG = 11.3) dropped in air. The properties of air are ρ = 1.22 kg/m3 and μ = 1.81 × 10-5 kg/m s.
A packed bed is composed of crushed rock with a density of 200 lb/ft3 with an assumed particle diameter of 0.15 in. The bed is 8 ft deep, has a porosity of 0.3, and is covered by a 3 ft layer of
A hollow steel sphere, 5 mm in diameter with a mass of 0.05 g, is released in a column of liquid and attains an upward terminal velocity of 0.005 m/s. The liquid density is 900 kg/m3, and the sphere
In a particular sedimentation vessel, small particles (SG = 1.1) are settling in water at 25°C. The particles have a diameter of 0.1 mm. What is the terminal velocity of the particles? Validate any
Air enters and passes up through a packed bed of solids 1 m in height. Using the data provided, what are the pressure drop and the outlet pressure? Data: Vs = 1m/s T = 293 K Dp Ps = 1 mm = 3 9500
At West Virginia University, each Halloween, there is a pumpkin-drop contest. College, high-school, and middle-school students participate. The goal is to drop a pumpkin off the top of the main
In the regeneration of a packed bed of ion-exchange resin, hydrochloric acid (SG = 1.2, μ = 0.002 kg/m3s) flows upward through a bed of resin particles (particle density of 2500 kg/m3). The bed is
A gravity filter is made from a bed of granular particles assumed to be spherical. The bed porosity is 0.40. The bed has a diameter of 0.3 m and is 1.75 m deep. The volumetric flowrate of water at
Calculate the flowrate of air at standard conditions required to fluidize a bed of sand (SG = 2.4) if the air exits the bed at 1 atm and 70°F. The sand grains have an equivalent diameter of 300 μm,
A manometer containing oil with a specific gravity (SG) of 1.28 is connected across an orifice plate in a horizontal pipeline carrying seawater (SG = 1.1). If the manometer reading is 16.8 cm, what
Water is flowing downhill in a pipe that is inclined 35° to the horizontal. A mercury manometer is attached to pressure taps 3 in apart. The interface in the downstream manometer leg is 1.25 in
An orifice having a diameter of 1 in is used to measure the flowrate of SAE 10 lube oil (SG = 0.928, μ = 60 cP) in a 2.5-in, schedule-40, commercial-steel pipe at 70°F. The pressure drop across the
Refer to Figure P19.69. Answer the following questions. Explain each answer.At what flowrate is NPSHA = 3.2 m? Comment on the feasibility of operating at this flowrate.At what flowrate does the pump
You must install a centrifugal pump to transfer a volatile liquid from a remote tank to a point in the plant 1000 ft from the tank. To minimize the distance that the power line to the pump must be
Benzene at atmospheric pressure and 41°C is in a tank with a fluid level of 15 ft above a pump. The pump provides a pressure increase of 50 psi to a destination 25 ft above the tank fluid level. The
Acrylic acid at 89°C and 0.16 kPa (ρ = 970 kg/m3, μ = 0.46 cP) leaves the bottom of a distillation column at a rate of 1.5 L/s.The bottom of a distillation column may be assumed to behave like a
Consider the pump and system curves indicated by the data in Table P19.72. Answer the following questions.If the source and destination are at the same height, what is the pressure change from source
A gas is to be cooled from 100°C to 45°C using cooling water that enters the heat exchanger at 30°C and leaves at 40°C. What is the LMTD for the heat exchanger if the flow of the streams is 1.
Why is it necessary to include an LMTD correction factor (F) into the design equation for most practical heat exchangers?
For the streams and flow configurations used in Example 20.1, what is the lowest temperature to which the gas stream can be cooled assuming the cooling water must leave the exchanger at 40°C?Example
Explain why you agree or disagree with this statement: Because the heat transfer coefficients for gases are always much lower than for liquids, the limiting resistance for condensers (where a gas is
Low-pressure steam at 160°C is used to heat very viscous oil from 30°C to 65°C in a heat exchanger located at the inlet to a pump. The amount of energy needed to heat the oil is 2.65 GJ/h. Over
For shell-and-tube exchangers in which the flow is turbulent and there is no phase change taking place for either stream, how does the heat transfer coefficient change with a 50% increase in the mass
1. A 1–2, S-T heat exchanger is used to cool a process stream from 70°C to 50°C using cooling water at 30°C heated to 40°C. For this heat exchanger, determine the value of F1-2.2. Repeat this
Repeat Problem 20.3 assuming laminar flow for both fluids.Problem 20.3For shell-and-tube exchangers in which the flow is turbulent and there is no phase change taking place for either stream, how
How many shell passes would be needed to cool a heavy oil stream from 230°C to 150°C using another process stream that is heated from 130°C to 190°C?What is the LMTD correction factor for this
Would you expect the heat transfer coefficient for a given fluid to be higher if the fluid were in laminar flow or turbulent flow? Explain your answer.
Give three reasons for placing a specific fluid on the tube side of an S-T heat exchanger.
Consider the same conditions and fluids in Example 20.6, except use a liquid velocity of 0.1 ft/s (0.03048 m/s) and a gas velocity of 2 ft/s (0.6096 m/s).Example 20.6Use Equation (20.26) to determine
Give three reasons for placing a specific fluid on the shell side of an S-T heat exchanger.
Water flows across the outside of a bank of tubes. It enters at 30°C and leaves at 40°C. The water enters at a flowrate of 34.27 kg/s, the shell diameter is 20 in, the baffle spacing is half (½)
Estimate the critical heat flux for water at 1 atm pressure using Equations (20.45) and (20.46) and compare with the value given in Figure 20.28.Properties of water at 1 atm pressure (P = 1.013 ×
Why are fins (extended surfaces) used in some heat exchangers?
Use Equations (20.47) and (20.48) to estimate the heat flux and heat transfer coefficient for water at 1 atm pressure for a temperature driving force of 10°C. 1/2 g 1 (pi- pu) T-RA(MIRRY)
Give explanations for the following terms for S-T heat exchangers:Baffle cut Number of tube passes Tube pitch Tube arrangement
An organic liquid (1-propanol at 1 bar) is to be vaporized inside a set of vertical 1-in BWG 16 tubes using condensing steam on the outside of the tubes to provide the energy for vaporization. The
State the basic design equation for an S-T heat exchanger in which there are no phase changes, and draw a sketch of the T-Q diagram with the relevant terms shown.
Draw the T-Q diagram for the following cases:Condensing (pure) vapor using cooling waterDistillation reboiler using condensing steam as the heating mediaProcess liquid stream cooled by a another
A process fluid (Stream 1) (Cp = 2100 J/kg/K) enters a heat exchanger at a rate of 3.4 kg/s and at a temperature of 135°C.This stream is to be cooled with another process stream (Stream 2) (cp =
Calculate the heat transfer coefficient for water boiling at 42 bar pressure (253.3°C) in the shell side of a waste heat boiler equipped with 1.25 BWG 12 tubes.Assume that the tube wall temperature
Repeat Problem 20.12 for the case when the specific heat capacities of both streams vary linearly with temperature with the following values:Stream 1: Cp = 2000 + 3(T − 100) J/kg/KStream 2: cp =
An S-T condenser contains four rows of four copper tubes per row on a square pitch. The tubes are 1-in, 16 BWG and 6 ft long.Cooling water flows through the tubes such that hi = 1000 BTU/hr/ft2/°F.
The T-Q diagrams for three S-T heat-exchanger designs are given in Figure P20.14(a–c). Determine the number of S-T passes required to accomplish these designs.
An aluminum heat transfer surface that is maintained at 100°C is in contact with air at 20°C. The film heat transfer coefficient between the surface and the air is estimated to be 42 W/m /K.
At a given point in a thin-walled heat exchanger, the shell-side fluid is at 100°C and the tube side fluid is at 20°C. Ignoring any fouling resistances and the resistance of the wall, determine the
Determine a preliminary rating for a heat exchanger with the following service:19,900 kg/h of kerosene leaves a distillation column at 200°C and will be cooled to 93°C by 67,880 kg/h of crude oil
An S-T exchanger is designed to exchange heat between two process streams. The T-Q diagram is shown in Figure E20.16. The inside and outside heat transfer coefficients are equal (hi = ho = 1000
In a heat exchanger, water (cp = 4200 J/kg/K) flows at a rate of 1.5 kg/s, and toluene (cp = 1953 J/kg/K) flows at a rate of 2.2 kg/s. The water enters at 50°C and leaves at 90°C, and the toluene
A hot, viscous process stream is cooled using cooling water (cw). The exchanger is a double-pipe design in which the cooling water flows in the annulus and the viscous process fluid flows in the
At a given location in a double-pipe heat exchanger, the bulk temperature of the fluid in the annulus is 100°C, and the bulk temperature of the fluid in the inner pipe is 20°C. The tube wall is
A single phase fluidis to be cooled from 175°C to 75°C by exchanging heat with another single phase fluidwhich is to be heated from 50°C to 150°C. You have the choice of one of the following five
Use Equations (20.47) and (20.48) to estimate the heat flux and heat transfer coefficient for boiling acetone at 1 atm pressure for a temperature driving force of 10°C. You may assume a C value of
A reboiler for a column is supplied with saturated steam (in shell) at a temperature of 145°C and reboils the bottom product (in tubes) that leaves the column at 122°C. It is desired to increase
What is the critical nucleate boiling flux for water at 20 atm?
Revisiting Example 20.18, by how much should the steam temperature be increased in order to achieve the 15% increase in boil-up rate for the case when the process-and steam-side heat transfer
Water flows inside a long ¾-in, 16 BWG tube at an average temperature of 110°F. Determine the inside heat transfer coefficient for the following cases:Velocity = 0.1 ft/s Velocity = 3 ft/s
A condenser is used to condense saturated steam to saturated liquid at 150°C (shell) using a process stream entering at 30°C and exiting at 50°C (tubes). Assume that the condensation resistance is
Use the Sieder-Tate equation to determine the inside heat transfer coefficient for a fluid flowing inside a 16 ft long, 1-in tube (14 BWG) at a velocity of 2.5 ft/s that is being cooled and has an
Water at 5 atm pressure and 30°C flows at an inlet velocity of 1 m/s into a square duct 2.5 m long that has a cross section of 25 mm by 25 mm. The wall of the duct is maintained at a temperature of
An S-T condenser contains six rows of five copper tubes per row on a square pitch. The tubes are ¾-in, 14 BWG, and 3 m long. Cooling water flows through the tubes such that h = 2000 W/m2/K. The
A double-pipe heat exchanger consists of a length of 1-in, schedule-40 pipe inside an equal length of 3-in, schedule-40 pipe.Water flows at a velocity of 1.393 m/s in the annular region between the
Liquid dimethyl ether (DME) flows across the outside of a bank of tubes. It enters at 100°C and leaves at 50°C. The DME enters at a flowrate of 20 kg/s, the shell diameter is 15 in, the baffle
A 3 m long, 1.25-in, BWG 14 copper tube is used to condense ethanol at 3 bar pressure. Cooling water at 30°C flows through the inside of the tube at a high rate such that the wall temperature may be
Air (1 atm and 30°C) flows crosswise over a bare copper tube (1-in, BWG 16). The approach velocity of the air is 20 m/s.Water enters the tube at 140°C and leaves the tube at an average temperature
Oil flows inside a thin-walled copper tube of diameter Di = 30 mm. Steam condenses on the outside of the tube, and the tube wall temperature may be assumed to be constant at the temperature of the

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