Questions and Answers of Analysis Synthesis And Design Of Chemical Processes

Identify the main reactant and product process streams for the following:The drying oil production facility shown in Figure B.4.1, Appendix B Table B.4.1 Stream Table for Unit 500
Identify the main recycle and bypass streams for the following:The styrene production facility shown in Figure B.3.1, Appendix B Table B.3.1 Stream Tables for Unit 400 Stream Number Temperature
Establish the primary flow pathway for1. Hydrogen between its introduction as a feed and the reactor2. Methane between its generation in the reactor and the discharge from the process as a product
For the toluene hydrodealkylation PFD given in Figure E5.1, identify all recycle and bypass streams.
Identify the main reactant and product process streams for the following:The maleic anhydride production process shown in Figure B.5.1, Appendix B V-601 C-601 Benzene Inlet Air Feed
Identify the main reactant and product process streams for the following:The ethylene oxide anhydride production process shown in Figure B.6.1, Appendix B A-701 EO
Identify the main reactant and product process streams for the following:The formalin production process shown in Figure B.7.1, Appendix B C-801 P-801 A/B Feed Air Methanol Compressor Feed
Identify the main recycle and bypass streams for the following:The drying oil production facility shown in Figure B.4.1, Appendix B Table B.4.1 Stream Table for Unit 500
Write a process description for the following:The ethylbenzene process shown in Figure B.2.1, Appendix B Table B.2.1 Stream Table for Unit 300- Stream Number Temperature (°C) Pressure (kPa) Vapor
Identify the main recycle and bypass streams for the following:The maleic anhydride production process shown in Figure B.5.1, Appendix B V-601 C-601 Benzene Inlet Air Feed Compressor Drum Dibutyl
Write a process description for the following:The drying oil production facility shown in Figure B.4.1, Appendix B Table B.4.1 Stream Table for Unit 500
Write a process description for the following:The ethylene oxide production facility shown in Figure B.6.1, Appendix B A-701 EO Reactor Ethylene Oxygen E-701 E-702 Reactor Reactor Preheater Effluent
The maximum allowable tensile strengths for typical carbon steel and stainless steel at ambient temperature, 400°C, and 550°C are provided belowDetermine the fractional decrease in the maximum
It is necessary to provide a nitrogen stream at 80°C and a pressure of 6 bar. The source of the nitrogen is at 200°C and 1.2 bar. Determine the work and cooling duty required for three
State two common criteria for setting the pressure of a distillation column.
Suggest two reasons each why distillation columns are run above or below ambient pressure. Be sure to state clearly which explanation is for above and which is for below ambient pressure.
For the PFD presented in Figure 1.5,1. Calculate the actual conversion.2. Evaluate the equilibrium conversion at 600°C.Assuming ideal gas behavior: K = (Nbenzene Nmethane)/(NtolueneNhydrogen) where
Suggest two reasons why reactors are run at elevated pressures and/or temperatures. Be sure to state clearly which explanation is for elevated pressure and which is for elevated temperature.
For the styrene production process given in Project B.3 in Appendix B, do the following:1. Construct a process conditions matrix (PCM) for the process, and determine all conditions of special
It has been proposed that the hydrogen/methane stream is handled in the same manner as was the toluene/benzene stream. Recall that the unreacted toluene was separated from the benzene product and
Reduce the amount of hydrogen in the feed to the reactor to the stoichiometric amount—that is, 144 kmol/h—and determine the effect on the equilibrium conversion at 600°C.Example 6.3For the PFD
Give two reasons why operation of a process at greater than 250°C is undesirable. Give one reason each why one would operate a distillation column and a reactor at a temperature greater than 250°C.
The activation energy for the rate of reaction for the hydrodealkylation of toluene is equal to 148.1 kJ/mol. What is the reaction rate at 600°C relative to that at 400°C?
For the production of drying oil shown as Project B.4 in Appendix B do the following:1. Construct a process conditions matrix (PCM) for the process, and determine all conditions of special concern.2.
Define a “condition of special concern.” Define two such conditions, and state one possible justification for each.
In the food and drug industries, many processes used to produce new active ingredients (drugs) or to separate and purify drugs and foods occur at vacuum conditions and often at low temperatures (less
For the separation of a binary mixture in a distillation column, what will be the effect of an increase in column pressure on the following variables?1. Tendency to flood at a fixed reflux ratio2.
In a new chemical process, a reboiler for a tower requires a heating medium at 290°C. Two possible solutions have been suggested: (a) Use high-pressure steam superheated to 320°C, and (b) Use
As the ambient temperature and humidity increase, the temperature at which cooling water (cw) can be supplied to any piece of equipment increases. For example, in the winter, cw may be available at
It is desired to produce a hot vapor stream of benzene to feed a reactor for a certain petrochemical process. The benzene is available from an off-site storage facility at 1 atm pressure and ambient
One way to produce very pure oxygen and nitrogen is to separate air using a distillation process. For such a separation determine the following:1. Find the normal boiling point (at 1 atm pressure) of
The production of ammonia (a key ingredient for fertilizer) using the Haber process takes place at temperatures of around 500°C and pressures of 250 atm using a porous iron catalyst according the
Consider the ammonia process in Problem 6.12. For the given conditions, the maximum single-pass conversion obtained in the reactor is about 15%−20%. Explain how the temperature and pressure should
What are the three main factors that determine the capital cost of a piece of equipment such as a heat exchanger at a given time?
The estimated capital cost for a chemical plant using the study estimate method (Class 4) was calculated to be $2 million. If the plant were to be built, over what range would you expect the actual
What is the Chemical Engineering Plant Cost Index (CEPCI) used for, and what does it measure?
Compare the costs for performing an order-of-magnitude estimate and a detailed estimate for a plant that cost $5.0 × 106 to build.
What is the difference between the total module cost and the grassroots cost of a chemical process?
Use the six-tenths rule to estimate the percentage increase in purchased cost when the capacity of a piece of equipment is doubled.
Compare the error for the scale-up of a reciprocating compressor by a factor of five using the six-tenths rule in place of the cost exponent given in Table 7.3. Table 7.3 Typical Values of Cost
When would you use a cost exponent of 0.6?
What is meant by the economy of scale?
The purchased cost of a recently acquired heat exchanger with an area of 100 m2 was $10,000.DetermineThe constant K in Equation (7.2)The cost of a new heat exchanger with area equal to 180 m2 Ca = K
What is a Lang Factor?
The purchased cost of a heat exchanger of 500 m2 area in 1996 was $25,000.Estimate the cost of the same heat exchanger in 2011 using the two indices introduced above.Compare the results.Estimate the
The pressure factor FP for a shell-and-tube heat exchanger is significantly smaller than for a vessel over the same pressure range. Why is this so?
The capital cost of a 30,000 tonne/y isopropanol plant in 1996 was estimated to be $23 million. Estimate the capital cost of a new plant with a production rate of 50,000 tonne/year in 2016.
The cost of a plant to produce 1.27 million tonne/y of polyethylene was $540 million. Estimate what the range of cost estimates would likely have been for a Class 5, a Class 3, and a Class 1 estimate.
Provide preliminary identification of the important chemical species in each of the three recycle streams identified in Example 5.3. See Figures E5.3(a), E5.3(b) (a), and E5.3(b)(b).Example 5.3For
For the reactor given in Example 22.9, determine the pressure drop across the reactor. Assume that the gas has the properties of air at the inlet conditions.Example 22.9The synthesis of phthalic
Repeat Example 22.9 for the case when catalyst is placed in a packed bed without internal cooling, as shown in Figure 22.8(a). Determine the temperature and conversion profiles within such a packed
Reexamine Problem 22.9 for the following cases:1. Design a packed bed reactor with intercooling (shell-and-tube design)using a cooling medium with a phase change (Tboil = 350°C) to obtain 80%
Consider the reactor in Example 22.9 using an inlet oxylene partial pressure of 0.0175 bar. Without dilution, this feed concentration leads to a runaway condition in the reactor. Explore the
For the stirred tank reactor in Example 22.8, determine whether the chosen operating/design point (T= 93.5, X = 80%, Tc,1 = 20C, TC,2 = 30C, and A = 3.96 m2) represents a stable operating condition.
Using the data from Example 22.3, determine the volume of catalyst needed to convert 80% of a feed of pure methanol (at a rate of 12,500 kg/h) at 14 atm and 250°C in an adiabatic packed bed reactor
Consider the reaction in Example 22.4, which described the isothermal liquid-phase conversion of feed A to product B in a plug flow reactor. The reactor volume was found for a given temperature, and
The problem statement for Example 22.8 was given as follows: An exothermic, liquid-phase reaction is to take place in a stirred tank reactor. The feed to the reactor (F)is pure A at 500 mol/min with
For the case of methanol synthesis discussed in Example 22.2, determine the appropriate expression for the equilibrium constant K(T) for the case when inerts are present in the feed along with the
In Example 22.9, the temperature and conversion profiles along the length of a plug flow reactor were generated for the production of phthalic anhydride from o-xylene assuming an overall heat
In Example 22.9, the temperature and conversion profiles along the length of a plug flow reactor were generated for the production of phthalic anhydride from o-xylene assuming a tube diameter of 1 in
In Example 22.9, the temperature and conversion profiles along the length of a plug flow reactor were generated for the production of phthalic anhydride from o-xylene assuming a particle size of 3
One technique to control the generation of a hot spot at the beginning of a reactor is to load the front end of the reactor with a diluted catalyst and then to load the remainder of the reactor with
In Example 22.9, the secondary combustion reaction of oxylene was ignored. If this reaction can be approximated by the following reaction rate, rework the example for inlet partial pressures of
In the production of cumene from propylene, the following elementary, vapor-phase, irreversible reaction takes place:The reaction rate is given byThe feed to a fluidized bed reactor consists of an
Consider a liquid-phase reaction occurring in a constantvolume, isothermal, batch reactor.1. For a first-order decomposition, what is the ratio of the time to reach 75% conversion to the time to
Consider the dehydration of isopropyl alcohol (IPA) to yield acetone and hydrogen:This reaction is endothermic, with a heat of reaction of 57.2 kJ/mol. The reaction is kinetically controlled and
Repeat Problem 22.21 for a catalytic/enzymatic reaction with a rate expression of the formwhere cAo = 10 mol/L, k1 = 3.5 s-1, and k2 = 0.45 L/molProblem 22.21In an isothermal batch reactor, a
In an isothermal batch reactor, a first-order, irreversible, liquid-phase reaction, A → B, occurs. The initial concentration is CAo.1. By what percentage must the reaction time be increased to
For the setup in Problem 22.25, do the following:1. Reconfigure the utility flow to be countercurrent with the process gas and determine the conversion of IPA.2. Sketch the temperature concentration
For the setup in Problem 22.25, do the following:1. Determine the change in IPA conversion if the flowrate to the reactor increases by 25% but the utility flow does not change.2. Determine the change
It is known that for a certain second-order, elementary, gasphase reaction (first order in A, first order in B), the rate of reaction increases by 50% when the temperature goes from 250°C to 280°C.
Determine the pressure drop across the reactor tubes for Problem 22.25.Problem 22.25Consider the dehydration of isopropyl alcohol (IPA) to yield acetone and hydrogen:This reaction is endothermic,
Consider a liquid-phase reaction occurring in a constantvolume, isothermal CSTR.1. For a first-order decomposition, what is the ratio of the volume of reactor needed for 75% conversion to the volume
The catalytic decomposition of ozone in fluidized beds of silica particles impregnated with Fe2O3 was studied by Van Swaaij and Zuiderweg. The decomposition reaction for a given temperature and
Repeat Problem 22.29 for the case when the gas flows through the emulsion phase in plug flow.Problem 22.29The catalytic decomposition of ozone in fluidized beds of silica particles impregnated with
For the laminar flow reactor problem given in Example 22.6, determine the volume of the reactor needed to obtain a conversion of 95%. Example 22.6 Using the results from Example 22.4, Part (b),
For the laminar flow reactor problem given in Example 22.6, determine the flowrate of feed needed to increase the conversion to 95%. Example 22.6 Using the results from Example 22.4, Part (b),
For the laminar flow reactor problem given in Example 22.6, determine conversion in the reactor when the flowrate of feed is increased by 25%. Example 22.6 Using the results from Example 22.4, Part
A vessel is to be designed to withstand an internal pressure of 10 MPag (1450 psig) at 250°C. The tangentto-tangent length (z) of the vessel is 15 m, and the inside diameter (Di) is 1.52 m. The
A vertical vessel is to be designed to remove water drops from air prior to a blower. The vessel operates at 2 bar pressure and 50°C. Determine the appropriate vessel diameter to remove 100 μm
The term E (weld efficiency) is used in the basic equation for determining the thickness of a pressure vessel. Does this term appear on the top or the bottom of the equation?
What is the corrosion allowance, why is it important, and what are typical values?
A vertical V-L separator is used to disengage benzene and toluene from a fuel gas stream at 24 bar pressure.Determine the diameter of the vessel required to ensure that no liquid droplets greater
Consider a horizontal drum used to separate a V-L mixture. The HHAL of the liquid is set at 0.8 Dves and the vapor and liquid properties are:Determine the diameter of the drum, Dves. PL = 1000
What is the minimum thickness of a pressure vessel? Would you still specify this thickness for a vessel that operated at an absolute pressure of 1.01 bar (1 atm)? Why?
Using the result from Example 23.4 and assuming a 10- minute holdup time for the liquid and a liquid flowrate of 35 m /h, determine the length of the vessel.Example 23.4Consider a horizontal drum
What are the two most common types of head (end piece) used in the construction of pressure vessels?
Using the results from Examples 23.4 and 23.5, estimate the maximum size of droplet that will be entrained with the gas stream assuming that the liquid level is at the NOL. A diagram of the vessel is
What is meant by a design-by-rule philosophy?
Estimate the diameter of a vertical V-L separator containing a 4-in (100 mm) thick wire mesh mist eliminator. The properties of the gas and liquid areConsider a mist eliminator with a kSB = 0.11 m/s
What is the purpose of a vapor-liquid (V-L) knockout drum?
Determine the pressure drop in the mist eliminator designed in Example 23.7. Using this result, do the following:1. Determine the fraction of 4 μm particles that are captured in the device at the
For a simple V-L knockout drum, give three reasons for using a vertically oriented drum.
For a simple V-L knockout drum, give three reasons for using a horizontally oriented drum.
Estimate the leak of air into a system comprising the acrylic acid tower and associated equipment and piping for the process flow diagram shown in Figure 23.14. Overhead CW Condenser Acrylic
Sketch three typical inlet devices for a V-L drum.
Design a steam ejector system for the acrylic acid distillation tower shown in Figure 23.14 and discussed in Example 23.9. Steam is available at 180°C and 1000 kPa, and the air leaking into the
Estimate the flowrate of medium pressure steam (T = 180°C, Pa = 1000 kPa) required to remove an air leak of 300 kg/h into an overhead condenser system operating at 27.5 kPa pressure and 50°C using
What is the meaning of HHAL and LLAL in the design of a vertical vessel?
In the design of a vertical V-L separator, what geometric parameter of the drum (dimension) controls the size of liquid drops leaving with the vapor? Explain your answer.

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