Questions and Answers of Chemical Biochemical And Engineering

Redo Problem 6.13 using Aspen PlusProblem 6.13Eighteen kilograms of the refrigerant HFC-134a at 150°C is contained in a 0.03-m3 tank. Compare the prediction you can make for the pressure in the tank
Redo Problem 6.12 using Aspen PlusProblem 6.12Ethylene at 30 bar and 100°C passes through a heaterexpander and emerges at 20 bar and 150°C. There is no flow of work into or out of the
Redo Problem 6.7 using Aspen PlusProblem 6.7One hundred cubic meters of carbon dioxide initially at 150°C and 50 bar is to be isothermally compressed in a frictionless piston-and-cylinder device to
One kilogram of saturated liquid methane at 160 K is placed in an adiabatic piston-and-cylinder device, and the piston will be moved slowly and reversibly until 25 percent of the liquid has
Repeat Illustration 6.7-1 using the Soave–RedlichKwong equation of state.Illustration 6.7-1 Using the Peng-Robinson Equation of State to Solve a Real Gas Problem Rework Illustration 6.5-1 assuming
Repeat Illustration 6.4-1 using the Soave–RedlichKwong equation of state.Illustration 6.4-1Making of a Thermodynamic Properties Chart As an introduction to the problem of constructing a chart or
Ammonia is to be isothermally compressed in a specially designed flow turbine from 1 bar and 100°C to 50 bar. If the compression is done reversibly, compute the heat and work flows needed per mole
The divided tank of the preceding problem is replaced with two interconnected tanks of equal volume; one tank is initially evacuated, and the other contains methane at 500 bar and 20°C. A valve
A tank is divided into two equal chambers by an internal diaphragm. One chamber contains methane at a pressure of 500 bar and a temperature of 20°C, and the other chamber is evacuated. Suddenly, the
Eighteen kilograms of the refrigerant HFC-134a at 150°C is contained in a 0.03-m3 tank. Compare the prediction you can make for the pressure in the tank with that obtained using Fig. 3.3-4. For
Derive Eqs. 6.6-2 and 6.6-3, and show that Zc|van der Waals = 3/8. Eqs. 6.6-2Eqs. 6.6-3, (OP) 7 / Va T evaluated at Te,Pe,Ve (OVP) evaluas = 0 = evaluated at Te, Pe.Ve = 0 = = 2a RTC (Ve-b)²
One of the beauties of thermodynamics is that it provides interrelationships between various state variables and their derivatives so that information from one set of experiments can be used to
Redo Problem 5.25 using Aspen Plus. Problem 5.25Repeat the calculation of problem 5.23 if the compressor has an isentropic efficiency of 87%.Problem 5.23Repeat the calculation of problem 5.22 with
Redo Problem 5.24 using Aspen Plus.Problem 5.24Repeat the calculation of problem 5.22 if the compressor has an isentropic efficiency of 72%. Problem 5.22Isobutane is to be liquefied to make liquid
In a continuous manufacturing process, chlorodifluoromethane (CHClF2) initially at 10 bar and 420 K, passes through an adiabatic pressure reducing valve so that its pressure is 0.1 bar (this last
The inlet to an adiabatic turbine is steam at 1.3 MPa and 385°C, and the turbine exit pressure is 0.1 MPa. a. Determine the maximum work that can be obtained from each kg of steam and the exit
Steam enters a turbine 350°C and 0.8 MPa and exits at 0.1 MPa.Compute the work exiting temperature and work obtained if: a. the turbine operates isentropically; and b. the turbine has an isentropic
From a process, 100 kg of steam is available at 2 MPa and 800°C. a. Determine the maximum amount of shaft work that can be obtained from this steam in a non-flow process if the ambient conditions
100 kg of steam is available at 2 MPa and 800◦C. a. Determine the maximum amount of shaft work that can be obtained from this steam in a non-flow process if the ambient conditions are 25°C and 1
Repeat Problem 3.25, now considering nitrogen to be a real gas with the thermodynamic properties given in Fig. 3.3-3.Problem 3.25A 0.01-m3 cylinder containing nitrogen gas initially at a pressure of
Redo Problem 3.32 using Aspen Plus.Problem 3.32Nitrogen can be liquefied using a Joule-Thomson expansion process. This is done by rapidly and adiabatically expanding cold nitrogen gas from high
Repeat the calculation of Problem 3.25, but now assume that sufficient heat transfer occurs between the gas in the two cylinders that both final temperatures and both final pressures are the
A 0.01-m3 cylinder containing nitrogen gas initially at a pressure of 200 bar and 250 K is connected to another cylinder 0.005 m3 in volume, which is initially evacuated. A valve between the two
An isolated chamber with rigid walls is divided into two equal compartments, one containing gas and the other evacuated. The partition between the compartments ruptures. After the passage of a
The frictionless piston-and-cylinder system shown here is subjected to 1.013 bar external pressure. The piston mass is 200 kg, it has an area of 0.15 m2, and the initial volume of the entrapped ideal
The voltage drop across an electrical resistor is 10 volts and the current through it is 1 ampere. The total heat capacity of the resistor is 20 J/K, and heat is dissipated from the resistor to the
a. A 1-kg iron block is to be accelerated through a process that supplies it with 1 kJ of energy. Assuming all this energy appears as kinetic energy, what is the final velocity of the block? b. If
A nonconducting tank of negligible heat capacity and 1 m3 volume is connected to a pipeline containing steam at 5 bar and 370◦C, filled with steam to a pressure of 5 bar, and disconnected from the
Steam at 500 bar and 600°C is to undergo a JouleThomson expansion to atmospheric pressure. What will be the temperature of the steam after the expansion? What would be the downstream temperature if
In Joule’s experiments, the slow lowering of a weight (through a pulley and cable arrangement) turned a stirrer in an insulated container of water. As a result of viscosity, the kinetic energy
Water in the Niagara River approaches the falls at a velocity of 8 km/hr. Niagara Falls is approximately 55 m high. Neglecting air resistance, estimate the velocity of the water at the bottom of the
a. A bicyclist is traveling at 20 km/hr when he encounters a hill 70 m in height. Neglecting road and wind resistance (a poor assumption), what is the maximum vertical elevation gain the bicyclist
The following reaction occurs in air: for t in seconds and concentrations in kmol/m3. The reaction occurs in a constant-volume, 2-L vessel, and the initial concentration of NO is 1 kmol/m3 and that
At high temperatures phosphine (PH3) dissociates into phosphorus and hydrogen by the following reaction:for t in seconds. The reaction occurs in a constantvolume, 2-L vessel, and the initial
The insecticide DDT has a half-life in the human body of approximately 7 years. That is, in 7 years its concentration decreases to half its initial concentration. Although DDT is no longer in general
As a result of a chemical spill, benzene is evaporating at the rate of 1 gram per minute into a room that is 6 m × 6 m × 3 m in size and has a ventilation rate of 10 m3/min.a. Compute the
The following table lists the volumes of 1 gram of water and 1 gram of mercury as functions of temperature. a. Discuss why water would not be an appropriate thermometer fluid between 0°C and
For each of the cases that follow, list as many properties of the equilibrium state as you can, especially the constraints placed on the equilibrium state of the system by its surroundings and/or its
It is sometimes necessary to produce saturated steam from superheated steam (steam at a temperature higher than the vapor-liquid coexistence temperature at the given pressure). This change can be
A clever chemical engineer has devised the thermally operated elevator shown in the accompanying diagram. The elevator compartment is made to rise by electrically heating the air contained in the
The elevator in the previous problem is to be designed to ascend and descend at the rate of 0.2 m/s, and to rise a total of 3 m. a. At what rate should heat be added to the cylinder during the
Nitrogen gas is being withdrawn at the rate of 4.5 g/s from a 0.15-m3 cylinder, initially containing the gas at a pressure of 10 bar and 320 K. The cylinder does not conduct heat, nor does its
Air in a 0.3-m3 cylinder is initially at a pressure of 10 bar and a temperature of 330 K. The cylinder is to be emptied by opening a valve and letting the pressure drop to that of the atmosphere.
Repeat the calculation in Problem 3.25, but now assume that the second cylinder, instead of being evacuated, is filled with nitrogen gas at 20 bar and 160 K.Problem 3.25A 0.01-m3 cylinder containing
A 1.5 kW heater is to be used to heat a room with dimensions 3.5 m × 5.0 m × 3.0 m. There are no heat losses from the room, but the room is not airtight, so the pressure in the room is always
The piston-and-cylinder device shown here contains an ideal gas at 20 bar and 25◦C. The piston has a mass of 300 kg and a cross-sectional area of 0.05 m2. The initial volume of the gas in the
A 0.6 m diameter gas pipeline is being used for the long-distance transport of natural gas. Just past a pumping station, the gas is found to be at a temperature of 25◦C and a pressure of 3.0 MPa.
Nitrogen can be liquefied using a Joule-Thomson expansion process. This is done by rapidly and adiabatically expanding cold nitrogen gas from high pressure to a low pressure. If nitrogen at 135 K and
A very large mass M of hot porous rock equal to 1012 kg is to be utilized to generate electricity by injecting water and using the resulting hot steam to drive a turbine. As a result of heat
The human body generates heat by the metabolism of carbohydrates and other food materials. Metabolism provides energy for all biological activities (e.g., muscle contractions). The metabolic
Water is to be heated from its pipeline temperature of 20°C to 90°C using superheated steam at 450◦C and 2.5 MPa in a steady-state process to produce 10 kg/s of heated water. In each of the
People partially cool themselves by sweating, which releases water that evaporates. If during exercise a human “burns” 1000 kcal (4184 kJ) in one hour of exercise, how many grams of water must
It is thought that people develop respiratory infections during air travel because much of the airplane cabin air is recirculated. Airlines claim that using only fresh air in the cabins is too costly
A 5-kg copper ball at 75◦C is dropped into 12 kg of water, initially at 5◦C, in a well-insulated container. a. Find the common temperature of the water and copper ball after the passage of a
In a foundry, metal castings are cooled by quenching in an oil bath. Typically, a casting weighing 20 kg and at a temperature of 450◦C is cooled by placing it in a 150-kg involatile oil bath
a. Show that the rate at which shaft work is obtained or required for a reversible change of state in a closed system at constant internal energy and volume is equal to the negative of the product of
Steam at 700 bar and 600◦C is withdrawn from a steam line and adiabatically expanded to 10 bar at a rate of 2 kg/min. What is the temperature of the steam that was expanded, and what is the rate of
Two metal blocks of equal mass M of the same substance, one at an initial temperature Ti1 and the other at an initial temperature Ti2, are placed in a well-insulated (adiabatic) box of constant
A block of metal of total heat capacity CP is initially at a temperature of T1, which is higher than the ambient temperature T2. Determine the maximum amount of work that can be obtained on cooling
Hydrogen has an auto-ignition temperature of 853 K; that is, hydrogen will ignite spontaneously at that temperature if exposed to oxygen. Hydrogen is to be adiabatically and reversibly compressed
One mole of carbon dioxide is to be compressed adiabatically from 1 bar and 25◦C to 10 bar. Because of irreversibilities and poor design of the compressor, the compressor work required is found to
If it is necessary to compress hydrogen to a higher pressure than is possible with the single-compression step above, an alternative is to use two compressors (or a two-stage compressor) with
If the heat capacity of an ideal gas is given by Also develop expressions for this fluid that replace Eqs. 4.4-3 and 4.4-4. C = (a-R) +bT+cT²+dT³ + e/T² show that T₂ T₁ S(T2, V₂)-S(T₁,
The Ocean Thermal Energy Conversion (OTEC) project in Hawaii produces electricity from the temperature difference between water near the surface of the ocean (about 27◦C) and the 600 m deep water
A tank contains 20 percent liquid water and 80 percent steam by volume at 200◦C. Steam is withdrawn from the top of the tank until the fluid remaining in the tank is at a temperature of 150◦C.
a. Steam at 35 bar and 600 K enters a throttling valve that reduces the steam pressure to 7 bar. Assuming there is no heat loss from the valve, what is the exit temperature of the steam and its
Joe Unidel claims to have invented a steady-state flow device in which the inlet is steam at 300°C and 5 bar, he outlet is saturated steam at 100°C and 1 bar, the device is adiabatic and produces
Steam at 20 bar and 300◦C is to be continuously expanded to 1 bar. a. Compute the final temperature, the entropy generated, the heat required, and the work obtained per kilogram of steam if this
An isolated chamber with rigid walls is divided into two equal compartments, one containing steam at 10 bar and 370◦C, and the other evacuated. A valve between the compartments is opened to permit
In a large refrigeration plant it is necessary to compress a fluid, which we will assume to be an ideal gas with constant heat capacity, from a low pressure P1 to a much higher pressure P2.a. If the
An adiabatic turbine is operating with an ideal gas working fluid of fixed inlet temperature and pressure, T1 and P1, respectively, and a fixed exit pressure, P2. Show that a. The minimum outlet
A very simple solar engine absorbs heat through a collector. The collector loses some of the heat it absorbs by convection, and the remainder is passed through a heat engine to produce electricity.
a. Consider the following statement: “Although the entropy of a given system may increase, decrease, or remain constant, the entropy of the universe cannot decrease.” Is this statement true?
A portable engine of nineteenth-century design used a tank of compressed air and an “evacuated” tank as its power source. The first tank had a capacity of 0.3 m3 and was initially filled with air
It is necessary to estimate how rapidly a piece of equipment can be evacuated. The equipment, which is 0.7 m3 in volume, initially contains carbon dioxide at 340 K and 1 bar pressure. The equipment
a. Compute the maximum useful work that can be obtained when 1 kg of steam undergoes a closed system change of state from 30 bar and 600◦C to 5 bar and 300◦C when the atmospheric conditions are
A device is being marketed to your company. The device takes in hot, high-pressure water and generates work by converting it to two outlet streams: steam and low-pressure water. You are asked to
A 0.2-m3 tank containing helium at 15 bar and 22◦C will be used to supply 4.5 moles per minute of helium at atmospheric pressure using a controlled adiabatic throttling valve. a. If the tank is
An important factor in determining the extent of air pollution in urban areas is whether the atmosphere is stable (poor mixing, accumulation of pollutants) or unstable (good mixing and dispersion of
Diesel engines differ from gasoline engines in that the fuel is not ignited by a spark plug. Instead, the air in the cylinder is first compressed to a higher pressure than in a gasoline engine, and
A rigid, isolated container 300 L in volume is divided into two parts by a partition. One part is 100 L in volume and contains nitrogen at a pressure of 200 kPa and a temperature of 100◦C. The
In normal operation, a paper mill generates excess steam at 20 bar and 400°C. It is planned to use this steam as the feed to a turbine to generate electricity for the mill. There are 5000 kg/hr of
Atmospheric air is to be compressed and heated as shown in the figure before being fed into a chemical reactor. The ambient air is at 20◦C and 1 bar, and is first compressed to 5 bar and then
Redo Problem 4.17 using Aspen Plus.Problem 4.17Hydrogen has an auto-ignition temperature of 853 K; that is, hydrogen will ignite spontaneously at that temperature if exposed to oxygen. Hydrogen is to
One kilogram of saturated liquid methane at 160 K is placed in an adiabatic pistion-and-cylinder device, and the piston will be moved slowly and reversibly until 25 percent of the liquid has
A sugar mill in Florida has been disposing of the bagasse (used sugar cane) by open-air burning. You, as a new chemical engineer, determine that by using the dried bagasse as boiler fuel in the mill,
A well-insulated cylinder fitted with a frictionless piston initially contains nitrogen at 15°C and 0.1 MPa. The piston is placed such that the volume to the right of the piston is 0.5 m3, and there
Redo Problem 4.18 using Aspen Plus.Problem 4.18If it is necessary to compress hydrogen to a higher pressure than is possible with the single-compression step above, an alternative is to use two
If the piston in the previous problem is replaced by one that is a perfect conductor, so that after the valve is closed the temperatures of the gas on the two sides of the piston equalize (clearly,
A tank of 0.1 m3 volume initially containing nitrogen at 25◦C and 1 bar will be filled with compressed nitrogen at a rate of 20 mol/s. The nitrogen coming from the compressor and into the tank is
A stream of hot water at 85◦C and a rate of 1 kg/s is needed for the pasteurizing unit in a milk-bottling plant. Such a stream is not readily available, and will be produced in a well-insulated
Low-density polyethylene is manufactured from ethylene at medium to high pressure in a radical chain polymerization process. The reaction is exothermic, and on occasion, because of cooling system
Two separate experiments are performed on a gas enclosed in a piston-and-cylinder device, both starting from the same initial state. The result of the first experiment is to be used to predict the
Redo Problem 4.9 using Aspen Plus.Problem 4.9a. A steam turbine in a small electric power plant is designed to accept 4500 kg/hr of steam at 60 bar and 500◦C and exhaust the steam at 10 bar.
Redo Problem 4.4 using Aspen Plus. Problem 4.4Steam at 700 bar and 600◦C is withdrawn from a steam line and adiabatically expanded to 10 bar at a rate of 2 kg/min. What is the temperature of the
Redo Problem 4.11 using Aspen Plus.Problem 4.11Steam is produced at 70 bar and some unknown temperature. A small amount of steam is bled off just before entering a turbine and goes through an
Redo Problem 4.20 using Aspen Plus.Problem 4.20Steam at 20 bar and 300◦C is to be continuously expanded to 1 bar. a. Compute the final temperature, the entropy generated, the heat required, and
Redo Problem 4.38 using Aspen Plus.Problem 4.38Atmospheric air is to be compressed and heated as shown in the figure before being fed into a chemical reactor. The ambient air is at 20◦C and 1 bar,
Redo Problem 4.37 using Aspen Plus.Problem 4.37In normal operation, a paper mill generates excess steam at 20 bar and 400◦C. It is planned to use this steam as the feed to a turbine to generate
Redo Problem 4.40 using Aspen Plus.Problem 4.40A sugar mill in Florida has been disposing of the bagasse (used sugar cane) by open-air burning. You, as a new chemical engineer, determine that by

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