One useful heuristic is that for curves with a negative slope, it is generally better to use a CSTR. Similarly, when a curve has a positive slope, it is generally better to use a PBR. P a Individualized Solution P b 1 In order to find the age of the baby hippo, we need to know the volume of the stomach.
The Levenspiel Plot is shown: Autocatalytic Reaction 5 4. For the intestine, the Levenspiel plot for the intestine is shown below. The outlet conversion is 0. We first plot the inverse of the reaction rate versus conversion. For now, we will assume that conversion X will be less that 0. CDP2-A g Critique the answers to this problem. The rate of reaction for this problem is extremely small, and the flow rate is quite large. To obtain the desired conversion, it would require a reactor of geological proportions a CSTR or PFR approximately the size of the Los Angeles Basin , or as we saw in the case of the batch reactor, a very long time.
P a Note: This problem can have many solutions as data fitting can be done in many ways. See Polymath program Pfireflies. See Polymath program Pcrickets. See Polymath program Pants. So activity of bees, ants, crickets and fireflies follow Arrhenius model. So activity increases with an increase in temperature. Activation energies for fireflies and crickets are almost the same.
Insect Activation Energy Cricket Firefly Ant Honeybee P d There is a limit to temperature for which data for any one of he insect can be extrapolate. Data which would be helpful is the maximum and the minimum temperature that these insects can endure before death. Therefore, even if extrapolation gives us a value that looks reasonable, at certain temperature it could be useless. The temperature increases as we go from top to bottom of the column and consequently the rate of corrosion should increase.
There is virtually no HCN in the bottom of the column. These two opposing factors results in the maximum of the corrosion rate somewhere around the middle of the column. Therefore doubling the temperature will not necessarily double the reaction rate, and therefore halve the cooking time.
When you bake the potato, the heat transfer coefficient is smaller, but the temperature can be more than double that of boiling water. Therefore, So, option 4 is correct. For any reaction, the rate law cannot be written on the basis of the stoichiometric equation. It can only be found out using experimental data. In the evaluation of the specific reaction rate constant at o C the gas constant that should have been used was 8. In the same equation, the temperatures used should have been in K rather than oC.
The units for calculated k at oC are incorrect. The dimension of the reaction rate obtained is incorrect. This is due to the fact that the rate law that has been taken is wrong. P c Example For the concentration of N2 to be constant, the volume of reactor must be constant. Therefore the reverse reaction decreases. The units of the rate constant, k, will differ depending on whether partial pressure or concentration units are used.
See below for an example. This can be done with mass balances on each element involved in the reaction. Once all the coefficients are found, you can then calculate the yield coefficients by simply assuming the reaction proceeds to completion and calculating the ending mass of the cells.
The rate law is to be obtained from the experimental data. It has been mentioned as an elementary reaction in the problem statement but in the proposed solution the rate law is based on the reaction equation that has been divided by stoichiometric coefficient of A.
P a Example There would be no error! The initial liquid phase concentration remains the same. P h Individualized solution. P i Individualized solution. So, we get 0. But actually it is a second order reaction. Also when we increase the particle size from position A, we reach at point B, again there is a decrease in the conversion.
Assume the reaction temperature is K. P f The points of the problem are: 1 To note the significant differences in processing times at different temperature i. One minute to react and to fill and empty. It does not matter if the reactor is red or black.
In case of a , For a batch reactor. PFR with pressure drop: Alter the Polymath equations from part c. See Polymath program Pf-pressure. CB 0 L 10 ft lb mol P psig Assume that the reactions are irreversible and first order. Case 1: gal v0 X 0. Also, the reverse reaction begins to overtake the forward reaction near the exit of the reactor.
See Polymath program Pc. The cost of this storage could prove to be the more expensive alternative. A cost analysis needs to be done to determine which situation would be optimal.
What is the maximum number of moles of ethylene glycol CH2OH 2 you can make in one 24 hour period? The feed rate of ethylene cholorhydrin will be adjusted so that the volume of fluid at the end of the reaction time will be dm3. Now suppose CO2 leaves the reactor as fast as it is formed.
First try equal number of moles of A and B added to react. See Polymath program Pb. This results in a conversion of. CDGA d We must reexamine the mole balance used in parts a-c. The flow rates have changed and so the mole balance on species A will change slightly. Because species B is added to two different reactors we will also need a mole balance for species B. Since for every mole of CH3 2O consumed there are 3 moles of gas produced, the final pressure should be 3 times that of the initial pressure.
This would result in the pressure increasing faster and less time would be need to reach the end of the reaction. The opposite is true for colder temperatures. See Polymath program Pi. P j For equal molar feed in hydrogen and mesitylene. As the two components are created, the reactant concentration drops and equilibrium forces the production to slow. As those reactions reach equilibrium, the reactions that are still producing the two components are still going and the concentration rises again.
Finally the reactions that consume the two components lower the concentration as the products of those reactions are used up in other reactions. P m Individualized solution P Solution is in the decoding algorithm given with the modules ICM problem P a Assume that all the bites will deliver the standard volume of venom. This means that the initial concentration increases by 5e-9 M for every bite. After 11 bites, no amount of antivenom can keep the number of free sites above This means that the initial concentration of venom would be 5.
The best result occurs when a dose of antivenom such that the initial concentration of antivenom in the body is 5. The volume enclosed by these boundaries is referred to as the system volume. We shall perform a mole balance on species j in a system volume, where species j represents the particular chemical species of interest, such as water or NaOH Figure Figure Mole balance on species j in a system volume, V.
If all the system variables e. Figure Dividing up the system volume, V. The total rate of generation within the system volume is the sum of all the rates of generation in each of the subvolumes.
The reactor can be charged i. Section 1. It is referred to as the continuous-stirred used for? Equipment on the CRE Web site. It is normally operated at steady state and is assumed to be perfectly mixed; consequently, there is no time dependence or position dependence of the temperature, concentration, or reaction rate inside the CSTR. That is, every variable is the same at every point inside the reactor. Because the temperature and concentration are identical everywhere within the reaction vessel, they are the same at the exit point as they are elsewhere in the tank.
Thus, the temperature and concentration in the exit stream are modeled as being the same as those inside the reactor. In systems where mixing is highly nonideal, the well-mixed model is inadequate, and we must resort to other modeling techniques, such as residence time distributions, to obtain meaningful results.
This topic of nonideal mixing is discussed in Chapters 16, 17, and 18 on nonideal reactors. We note that the CSTR is modeled such that the conditions in the exit stream e. It consists of a cylindrical pipe and is When is a tubular normally operated at steady state, as is the CSTR. Tubular reactors are used reactor most often used? A schematic and a photograph of industrial tubular reactors are shown in Figure In modeling the tubular reactor, we assume that the concentration varies continuously in the axial direction through the reactor.
Consequently, the reaction rate, which is a function of con- centration for all but zero-order reactions, will also vary axially. Figure b Tubular reactor photo. Longitudinal tubular reactor. McGraw-Hill, Inc. That is, there is no radial variation in reaction rate, and the reactor is referred to as a plug-flow reactor PFR. Plug flow—no radial variations in velocity, concentration, temperature, or reaction rate Also see PRS and Visual Encyclope- dia of Equipment.
However, we see that by applying Equation , the result would yield the same equation i. As the reac- tants proceed down the reactor, A is consumed by chemical reaction and B is produced. The greater the mass of a given catalyst, the greater the reactive surface area. Consequently, the reaction rate is based on mass of solid catalyst, W, rather than on reactor volume, V.
Figure shows a schematic of an industrial catalytic reactor with vertical tubes packed with solid catalyst. Figure Longitudinal catalytic packed-bed reactor. The derivation of the design equation PBR Mole Balance for a packed-bed catalytic reactor PBR will be carried out in a manner analo- gous to the development of the tubular design equation.
To accomplish this der- ivation, we simply replace the volume coordinate in Equation with the catalyst mass i. Example 1—2 How Large Is It? Solution 1. Sketch CA as a function of V. CA0 CA 0. Calculate V. Again using Equation E We see that a reactor volume of 0. The more species A consumed and converted to product B, the larger must be the reactor volume V. The purpose of the example was to give a vision of the types of calculations we will be carrying out as we study chemical reaction engineering CRE.
There are also links to view reactors on different Web sites. Susan Montgomery and her students at the University of Michigan. Chapter 1 Summary 23 The CRE Web site describes industrial reactors, along with typical feed and operating conditions. The goal of this text is to weave the fundamentals of chemical reaction engineering into a structure or algorithm that is easy to use and apply to a variety of problems.
By convention, —rA is the rate of disappearance of species A and rA is the rate of formation of species A. Mole balances on species A in four common reactors are shown in Table S Summary Notes 2. Web Material A. Problem-Solving Algorithm B. Getting Unstuck on a Problem This Web site gives tips on how to overcome mental barriers in problem solving.
Smog in L. Web module includes a Living Example Problem. Getting Unstuck C. Interactive Computer Games A. Quiz Show I 4. The reactor portion of this encyclopedia is included on the CRE Web site.
Before solving the problems, state or sketch qualitatively the expected results or trends. Write a paragraph describing both the content goals and the intellectual goals of the course and text. Look at the QuickTime videos. Write a paragraph describing two or more of the reactors. What similarities and differences do you observe between the reactors on the Web e. How do the used reactor prices compare with those in Table ?
Go on a scavenger hunt using the summary notes for Chapter 1 on the Web site. Take a quick look at the Web Modules and list the ones that you feel are the most novel applications of CRE. QA What does a negative number for the rate of formation of species e. What does a positive number signify? QA What assumptions were made in the derivation of the design equation for: a The batch reactor BR?
Problems PA a Revisit Example Rework this example using Equation on page Explain why. Suggest two ways to work this problem incorrectly. Play this game and then record your performance number, which indicates your mastery of the material. The feed is only A and B in equimolar proportions. Which of the following sets of equations gives the correct set of mole balances on A, B, and C? Species A and B are disappearing and species C is being formed. Circle the correct answer where all the mole balances are correct.
We shall use this system volume to model the accumulation and depletion of air pollutants. We shall perform an unsteady-state mole balance Equation 1—4 on CO as it is depleted from the basin area by a Santa Ana wind. Santa Ana winds are high-velocity winds that originate in the Mojave Desert just to the northeast of Los Angeles. Use the data in the module to work parts 1—12 a through h given in the module. Load the Living Exam- ple Polymath code and explore the problem. These equation solvers will be used extensively in later chapters.
Also, plot the number of foxes versus the number of rabbits. Explain why the curves look the way they do. Enrico Fermi was an Italian physicist who received the Nobel Prize for his work on nuclear processes. He used a process to set bounds on the answer by saying it is probably larger than one number and smaller than another, and arrived at an answer that was within a factor of CDPl-B Points out difference in rate per unit liquid volume and rate per reactor volume.
Volumeon log-logpaper. Usethisgraphto generate anequationfor costasa functionof volume. In Cost Ys. In Volume Scott Fogler Solutions Manual February 0. Detail - Timber Construction - January 1. February 0. Dinding Penahan Tanah Ppt March 0. Analisa Data January 0. Chapter 3: Rate Laws 75 3. Chapter 4: Stoichiometry 4. Chapter 5: Isothermal Reactor Design: Conversion 5.
Chapter 7: Collection and Analysis of Rate Data 7. Chapter 8: Multiple Reactions 8. Chapter Catalysis and Catalytic Reactors Parameter Sensitivity Chapter Diffusion and Reaction Chapter Models for Nonideal Reactors Appendix A: Numerical Techniques A.
Appendix D: Software Packages D. Pearson offers affordable and accessible purchase options to meet the needs of your students. Connect with us to learn more.
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