Questions and Answers of Analysis Synthesis And Design Of Chemical Processes

Wood pellets, Stream 1 in Figure P13.32, are first dried by indirect heating with the flue gas and then combusted. Model this system using a heat exchanger, E-2001, followed by a flash separator,
Consider the removal of condensable components from the reactor effluent stream of an acetone production process, shown in Figure P14.5. The removal process consists of a cooling water exchanger and
Describe a Pareto analysis. When is it used?
What is the difference between parametric optimization and topological optimization? List one example of each.
In general, when using cooling water (cw) as a utility, the outlet temperature of the water leaving any process exchanger and returning to the cooling tower is limited to about 40°C to avoid
When pumping a liquid from one location to another, the diameter of the pipeline plays a critical role in determining the amount of power (electricity) required to pump the liquid. For a given flow
Consider the compression of feed air into a process that produces maleic anhydride, shown in Figure P14.6. The air enters the process at a rate of 10 kg/s at atmospheric pressure and 25°C. It is
What is an objective function? Give two examples of one.
A typical binary distillation column and related equipment are shown in Figure P14.9.When designing distillation columns, it is common to optimize the column using the reflux ratio, R, as the
A liquid-phase biological reaction is used to produce an intermediate chemical for use in the pharmaceutical industry. The reaction occurs in a large, well-stirred bioreactor that is illustrated in
Consider the problem given in Example 14.7 for the case when the reaction is 2A→B and the reaction is second order with respect to A. Derive an expression, similar to Equations (14.17) and (14.18),
A chemical process recovers heat by transferring energy from a gas stream to a cold brine stream. During the heating of the brine, salts deposit on the heat-exchanger surfaces and cause significant
Consider the determination of the optimal cycle time for a batch reactor similar to that covered in Example 14.7. Repeat the analysis using the following parameters:Example 14.7When pumping a liquid
Consider the following batch sequencing problem:Two chemicals A and B are to be produced. Each chemical requires the use of a mixer/reactor and a separator unit. The amount of each product made in a
Consider the problem described in the table below in which Products A, B, and C are made. The amount of each product made per batch is the same.At least 50 batches of each product must be produced in
Perform a parametric optimization for the second distillation column, T-202, in the DME process, Figure B.1.1, using reflux ratio and pressure as the independent variables and NPV as the objective
For the DME process shown in Figure B.1.1, complete a parametric optimization for both columns when the order of separation is reversed. This means that the first column will remove water as a
For the DME column (T-201), find the operating pressure at which a switch from medium-to low-pressure steam (for use in the reboiler, E-204) yields an improvement in the NPV. Discussion of what costs
List all the costs that are affected by changing the minimum temperature approach in a heat-exchanger network (HEN) design.
What are the advantages and disadvantages of decreasing the minimum approach temperature in a heat-exchange network?
One way to account for different materials of construction (MOCs) in heat-exchanger network design is to “adjust” the film heat transfer coefficients for streams that require MOCs other than
In heat-exchanger network designs, there exists an optimum ΔTmin for the network. Explain carefully how capital costs and operating costs change as ΔTmin is increased.
For designing heat exchangers at the pinch, what is the criterion for matching streams above the pinch? Why is such a criterion needed?
Sketch a typical composite enthalpy diagram for a heat-exchanger network. On this diagram clearly label the x- and y-axes, and indicate on the diagram the values and location of the overall hot and
What does the cascade diagram illustrate?
In general, what is the minimum number of exchangers required to design a heat exchanger network above the pinch that consists of n hot streams and m cold streams?
How does one deal with a stream that changes phase in a heat-exchanger network?
For a process, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 20°F.Determine the temperature
For a new process, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 10°F.Determine the temperature
What is MUMNE? Describe it.
For a new process, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 20°C.Determine the temperature
For a new process, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 10°F.Determine the temperature
In a process design, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 10°C.Determine the temperature
The temperature interval diagram for a process is shown in Figure P15.16. For this process do the following:Compute the missing values of ṁCp for Streams 2 and 3, the missing Q values for
In a process design, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 20°F.Determine the temperature
In a process design, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 20°C.Determine the temperature
In a process design, the following process streams must be cooled or heated:The hottest hot-utility stream is high-pressure steam at 254°C. Use the MUMNE algorithm for heat-exchanger networks and a
In a process design, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 10°C.Determine the temperature
In a process design, the following process streams must be cooled or heated:Determine the temperature interval diagram.Determine the cascade diagram, the pinch temperatures, and the minimum hot and
If the streams in Problem 15.22 have the following film heat transfer coefficients, estimate the optimum minimum approach temperature for this problem.Problem 15.22Six streams in a chemical process
Six streams in a chemical process need to be heated or cooled. The thermal data for these streams are given in the following table:Calculate the minimum hot and cold utility loads for this process
Rework Problem 15.23, for the case when the streams require special materials of construction with the following material factors:Problem 15.23If the streams in Problem 15.22 have the following film
Consider the following process streams, all containing the same solute. The partition coefficient between both rich phases and the lean phase is 0.5 (i.e., y = 0.5x).Synthesize the MUMNE
Consider the following process streams, all containing the same solute. The partition coefficient between both rich phases and the lean phase is 0.5 (i.e., y = 0.5x).Synthesize the MUMNE
Ethanol can be made by fermentation of grains such as corn. It can be fermented only up to a mass fraction of about 0.15 because higher concentrations kill the yeast. A big market for ethanol made
Consider the following process streams, all containing the same solute. The partition coefficient between both rich phases and the lean phase is 0.667 (i.e., y = 0.667x).Synthesize the MUMNE
Consider the following process streams, all containing the same solute. The partition coefficient between both rich phases and the lean phase is 0.667 (i.e., y = 0.667x).Synthesize the MUMNE
In a process design, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 20°C.Determine the temperature
In a process design, the following process streams must be cooled or heated:Use the MUMNE algorithm for heat-exchanger networks and a minimum approach temperature of 20°C. Determine the temperature
How are partitioning and precedence ordering carried out by a process simulator?
Consider a flowsheet containing a number of process loops for which a single tear stream is sufficient to ensure that each loop is opened at least once. Assume that you have a choice of two tear
In a flowsheet, a material stream consisting of six species is used as the tear stream. If Newton’s method is used for converging this stream, how many more flowsheet passes are required at each
A process flowsheet contains some sections that have a number of recycle streams with strong interactions while the other sections have very few recycle streams. What is the appropriate solution
What is an objective function? Give two examples of one.
In an EO-based optimization strategy, what do the equality constraints mainly represent?
List at least one strategy to check if there is any superior solution than the local solution.
In a line search approach, what might one do to solve the issue if the algorithm fails because of very small step size?
If a flowsheet has large number of recycle streams, what optimization method, SM or EO-based methods, would you suggest? Justify your answer.
In a reactor, unreacted reactants are recycled. Also, there is no undesired reaction in this reactor. Would flowrate of fresh reactants be a suitable decision variable for this problem? Justify your
In an optimization study with a flowsheet, how is the feasible region defined? Why is it important?
It is desired to solve a multi-objective optimization problem in a simulator that only supports single-objective optimization. Suggest an approach how the optimization problem can be formulated in
If you are estimating the binary interaction parameters of an SVE problem, what constraints are considered?
While estimating the parameters of a physical property model, it has been reported that the measurements of independent variables have negligible uncertainty. How should the maximum likleihood
Ethylene and air react in a vapor-phase catalytic reaction to form ethylene oxide.The system can be modeled by the PR EOS. The rate law is given by WanDevelop a base-case simulation considering a
Find the bare module cost (in 2016) of a stainless steel tower 3 m in diameter and 30 m tall. The tower has 40 stainless steel sieve trays and operates at 20 barg.The costs of the tower and trays are
A small expansion to an existing chemical facility is being investigated, and a preliminary PFD of the process is shown in Figure E7.14.The expansion involves the installation of a new distillation
When designing equipment for high-temperature and high-pressure service, the maximum allowable stress as a function of temperature of the material of construction is of great importance. Consider a
Using the results of Problem 7.13, determine the relative costs of the vessel using the two materials of construction (CS and 316 SS) over the temperature range. You may assume that the cost of the
Determine the bare module, total module, and grassroots cost of the following:Ethylbenzene plant described in Appendix B, Project B.2 B.2 ETHYLBENZENE PRODUCTION, UNIT 300 The majority of
Determine the bare module, total module, and grassroots cost of the following:Styrene plant described in Appendix B, Project B.3Figure B.3.1 B.3 STYRENE PRODUCTION, UNIT 400 Styrene is the monomer
Determine the bare module, total module, and grassroots cost of the following:Drying oil plant described in Appendix B, Project B.4Figure B.4.1 B.4 DRYING OIL PRODUCTION, UNIT 500 Drying oils are
A certain vendor estimates the cost of vertical drums made from stainless steel as a function of the volume (V) of the cylindrical portion of the drum and the diameter (d) of the end pieces. The cost
Determine the bare module, total module, and grassroots cost of the following:Toluene hydrodealkylation plant described in Chapter 1 (see Figures 1.3 and 1.5 and Tables 1.5 and 1.7)Figures 1.5 V-101
Estimate the cost of operating labor (COL), the cost of utilities (CUT), and the cost of manufacturing (COMd) for the ethylbenzene process given in Project B.2 of Appendix B. You must do Problem 7.22
Determine the cost of an air separation unit with a capacity of 1600 tonne/day of oxygen.Determine the cost of an air separation unit with a capacity of 3200 tonne/day of oxygen.Determine the cost of
Determine the bare module cost of a 1-shell-pass, 2-tube-pass (1-2) heat exchanger designed for the following operating conditions: Maximum operating pressure (tube side) = 30 bargMaximum operating
The following cost information was obtained from a design for a 92,000 tonne/y nitric acid plant:Determine1. The manufacturing cost in $/y and $/tonne of nitric acid2. The percentage of manufacturing
Repeat Problem 7.16, except reverse the shell-side and tube-side fluids. Are your results consistent with the heuristics for heat exchangers given in Chapter 11? Which heuristic is relevant?Problem
The concepts of heat-exchanger networks and pinch technology are discussed. When designing these networks to recover process heat, it is often necessary to have a close temperature approach between
A distillation column is initially designed to separate a mixture of toluene and xylene at around ambient temperature (say, 100°C) and pressure (say, 1 barg). The column has 20 stainless steel valve
A column with similar dimensions, number of trays, and operating at the same conditions as given in Problem 7.19 is to be used to separate a mixture containing the following chemicals. For each case
Determine the bare module, total module, and grassroots cost of the following:Ethylene oxide plant described in Appendix B, Project B.6Figure B.6.1 B.6 ETHYLENE OXIDE PRODUCTION, UNIT 700 Ethylene
Determine the bare module, total module, and grassroots cost of the following:Maleic anhydride plant described in Appendix B, Project B.5Figure B.5.1 B.5 PRODUCTION OF MALEIC ANHYDRIDE FROM BENZENE,
Estimate the cost of operating labor (COL), the cost of utilities (CUT), and the cost of manufacturing (COMd) for the styrene process given in Project B.3 of Appendix B. You must do Problem 7.23 in
Determine the bare module, total module, and grassroots cost of the following:Formalin plant described in Appendix B, Project B.7 B.7 FORMALIN PRODUCTION, UNIT 800 Formalin is a 37 wt% solution of
In the general equation for determining the cost of manufacturing (COM ), Equation (8.2), one of the terms is 0.180FCI, where FCI is the fixed capital investment of the plant. “This term is
Estimate the cost of operating labor (COL), the cost of utilities (CUT), and the cost of manufacturing (COMd) for the drying oil process given in Project B.4 of Appendix B. You must do Problem 7.24
Estimate the quantities and yearly costs of the appropriate utilities for the following pieces of equipment on the toluene hydrodealkylation PFD (Figure 1.5). It is assumed that the stream factor is
Why is the number of operators per shift multiplied by approximately 4.5 to obtain the total number of operators required to run the plant?
What is a stream factor?
In Equation (8.2), the cost of raw materials, CRM, is multiplied by a factor of 1.23. The reason for this is that, in general, the estimated cost of raw materials is expected to be about 20% low and
Cooling water is priced on an energy basis: $/GJ. The temperature rise is usually assumed to be 10°C. Does the cooling water cost change if the return temperature changes? Are there any limitations
In Equation (8.2), the cost of operating labor, COL, is multiplied by a factor of 2.73. One reason for this is that the value of COL includes only plant operators and not supervisory and clerical
Estimate the utility cost of a heat-transfer medium heated in a fired heater using natural gas as the fuel.
Explain the difference between direct costs, fixed costs, and general expenses. Give two examples of each.
When a chemical plant needs steam at multiple pressure levels, it is often economical to generate all the steam at a high pressure and then to let the steam down through pressure-reducing turbines to
You are employed at a chemical company and have recently been transferred from a plant that manufactures synthetic dyes to a new facility that makes specialty additives for the polymer resin
What are the operating costs associated with a typical cooling water system? Based on the example given in this chapter, answer the following:What percentage of the operating costs is the makeup
Determine the cost of producing a refrigerant stream at –50°C using propane as the working fluid in a noncascaded system. You may wish to refer to Example 8.5 to do this problem. The steps you
Estimate the cost of operating labor (COL), the cost of utilities (CUT), and the cost of manufacturing (COMd) for the ethylene oxide process given in Project B.6 of Appendix B. You must do Problem

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