CRO 410 Tut 8Question 1 The catalytic hydrogenation of methyl linoleate to methyl oleate was carried out in a laboratory-scale reactor in which hydrogen gas was bubbled up through the liquid containing spherical catalyst pellets. The pellet density is 2 g/cm 3 . The following experiments were carried out at 25°C: 1. It has been suggested that the overall reaction rate can be enhanced by increasing the agitation, decreasing the particle size, and installing a more efficient sparger. With which, if any, of these recommendations do you agree? Are there other ways that the overall rate of reaction might be increased? Support your decisions with calculations. 2. Is it possible to determine the effectiveness factorfrom the data above? If so, what is it? 3. For economical reasons concerning the entrainment of the small solid catalyst particles in the liquid, it is proposed to use particles an order of magnitude larger. The following data were obtained from these particles at 25°C: The Thiele modulus is 9,0 for the 750 μm particle size in run 4. Determine (if possible) the external mass transfer coefficient, k c , and the percent (of the overall) of the external mass transfer resistance to the catalyst pellet. Question 2 (2003 Q3 E) [10] A first order liquid reaction occurs in a packed bed reactor. The conversion is 80% if 1mm particles are used. 1. What will be the conversion if 2mm particles are used, if one assumes that internal mass transfer is controlling the rate for both particle sizes? [4] 2. What will be the conversion if 2mm particles are used, if one assumes that external mass transfer is controlling the rate for both particle sizes? [4] 3. If the shape of the packed bed is changed so that the reactor is longer and the diameter smaller (the same amount catalyst is used), how will the conversion change for the 2mm packed bed in (1). How will it change for the packed bed in (2). [2] Question 3 (Q4 2003 E) [22] A range of experiments were performed in a continuous slurry reactor where the following reaction occurs: ) ( ) ( ) ( l D g B l A ÷ + The reaction is first order with respect to B in the liquid phase and zero order with respect to A. Pure B is fed in complete excess to the sparger at the bottom of the reactor. Pure A is fed as liquid and a mixture of A and D flows as liquid out of the reactor. The following results were obtained for 3 different runs where only the catalyst concentration and size were varied. Pressure (bar) Conversion of A Catalyst conc. (g/l) Particle size (mm) 10 0.4 3 0.1 10 0.65 8.5 0.1 10 0.27 5 0.3 1. Prove that the volumetric reaction rate -r A (mol.l -1 .s -1 ) is directly proportional to the conversion of A for a given inlet flowrate and reactor volume. [2] 2. Does gas to liquid mass transfer influence the reaction rate? [4] 3. Does external (liquid to solid) or internal mass transfer influence the reaction rate? [6] 4. By using a different sparger in the same reactor, the average bubble size decreases from 3mm to 1.5mm, while the volumetric amount of gas in the liquid phase (gas holdup) remains the same. What will be the conversion in the reactor if 0.1 mm particles are used at a concentration of 4 g/l? [6] What will be the conversion if 0.2mm particles are used at a concentration of 4 g/l together with the improved sparger. Question 4 (Q2 2005 T1) [22] The following reversible exothermic reaction is studied in the liquid phase: C B A · + Figure 1 gives the necessary rate detail for this reaction for a given feed concentration. The following information is also supplied: Cp A = Cp B = 125 : Heat capacities (kJ/kmolK) AH = -20000 : constant heat of reaction (kJ/kmol A) Q = 2000 l/min a) If the reaction occurred in an isothermal PFR at a temperature of 55°C, what would the conversion-reactor length profile look like? Draw a qualitative sketch. [2] b) If the reaction occurred in an adiabatic PFR with an inlet temperature of 55°C, what would the conversion-reactor size profile look like? Draw a qualitative sketch with some numerical pointers. [3] c) If the reaction occurred in an adiabatic CSTR with an inlet temperature of 55°C, what would the conversion-reactor size locus look like? (Note that a locus implies that we use a separate size CSTR for each point on the locus line, unlike a PFR where we just increase the length to obtain the next point on the profile). Draw a qualitative sketch with some numerical pointers on the sketch in (b). Neatness will earn you extra marks! [4] d) For the reactors in (b) and (c), estimate the single amount of catalyst that will give you the same conversion in a PFR and CSTR. What is the conversion? [6] e) Estimate the minimum amount of cooling (in kW) required to obtain a 90% conversion, when the feed temperature is 80°C. What practical considerations will cause the cooling to be more? [4] f) Assume the reaction was endothermic. Explain the methodic that you would use to determine the single amount of catalyst that will give you the same conversion in an adiabatic PFR and adiabatic CSTR. [3] Question 5 (Q3 2005 E) [20] The first order irreversible liquid phase reaction (A->B) is studied in an adiabatic CSTR and an isothermal PFR with similar feeds (flowrate and concentration). The CSTR achieves a 80% conversion. The idea is to obtain the same conversion in the PFR using the same amount of catalyst. This can be done by varying the particle size in the PFR or the operating temperature of the PFR. The CSTR conditions (catalyst size and inlet temperature) remains the same and are specified below. Non ideal flow effects and external mass transfer can be neglected in this problem. Information of CSTR: Catalyst diameter - 1mm Inlet temperature - 200°C Information on the reaction Reaction enthalpy – -25 kJ/mol (exothermic) Heat capacity of A – 125 J/mol/K Activation energy on catalyst – 50kJ/mol Effective diffusivity of catalyst – 7e-8 m 2 /s Catalyst density – 2500 kg/m3 Inlet flowrate – 10 l/s Mass of catalyst – 10 kg 1. If the operating temperature of the PFR is 250°C, what size catalyst should be used? [10] 2. If the catalyst size in the PFR is 3mm at what temperature should the PFR be operated? [5] 3. If a adiabatic PFR was used with an inlet temperature of 250°C, will the rate be monotonically decreasing or not? [5] Question 6 (Q2 2005 E) [21] The first order irreversible liquid phase reaction (A->B) occurs in a packed bed reactor where external mass transfer is negligible. The intrinsic rate constant is known to be 0.5 l.kg -1 s -1 . A conversion of 54.9% is obtained. In the second run the reactor is length is doubled (2L), while the inlet conditions remain the same (same amount processed). Information of packed bed reactor: Effective diffusivity of catalyst - 1e-7 m 2 /s Catalyst diameter - 2mm Catalyst density 2000 kg/m3 Volumetric flowrate – 2000 l/min Weight of catalyst 100 kg 1. What is the effectiveness factor of the catalyst? [3] 2. Is the effectiveness factor a function of length for this example? Give the effectiveness factor at the entrance and exit conditions of the first run (length =L) [2] 3. What will be the conversion in the second run (2L)? [10] 4. If the catalyst size is halved (third run), what will be the conversion if the 2L reactor is used? You can assume that the Particle Reynolds number for all the runs (1-3) are below 20. [6] Question 7 (Q2 2007 E) [17] You are approached to re-design an existing adiabatic CSTR due to the development of a new catalyst. The new catalyst has the same activity as that of the old catalyst at 200°C, but due to a higher activation energy the activity of the catalyst is higher than that of the old catalyst above 200°C. The reactor performance should not alter from that of the old catalyst. The following is known about the reactor and old catalyst: First order reaction A->B Inlet temperature – 70°C Outlet temperature – 309°C Reaction enthalpy – 25 kJ/mol (exothermic) Pre exponential constant – 1000 l/g.s; Activation energy 35 kJ/mol Inlet flowrate of pure A – 200l/min at 15 mol/l Reactor volume –400 l, Catalyst concentration – 0.25 g/l – negligible mass transfer effects C PA – 100 J/molK; C PB – 100 J/molK The new catalyst has an activation energy of 50 kJ/mol. According to the plant engineer the old CSTR was very stable in its operation and he is concerned about the reactor with the new catalyst since, as he puts it “CSTR’s are known for erratic behaviour”. It is further safe to neglect all mass transfer effects on the reaction rate. a) What was the conversion in the old CSTR? [4] b) What should be the concentration of the new catalyst in the reactor to achieve the same conversion? [6] c) Any comments/suggestions on the stable operation of the reactor. [7] Question 8 (Q2 2008 T2) [16] The second order reaction A -> B+C occurs in the liquid phase in a CSTR. Initially 5 grams of solid 3mm spheres (solid density of 1200 kg/m 3 ) are suspended in 5 liters of liquid. The volume remains constant while a continious flow of 100 l/min of pure A at 6 mol/l is fed to the CSTR. Steady state is achieved within minutes, but it was noticed that there is a gradual increase in conversion over the 2 day period of the run. Closer examination of the mixture showed a gradual chopping action of the impeller, resulting in a decrease in the average particle size: The following measurements were reported: Time running (hours) Conversion Average particle diameter (mm) 0.1 0.529 3000 6 0.605 990 12 0.627 520 20 0.637 300 30 0.645 140 60 0.648 80 a) Does the active area of the catalyst increase with the chopping of the catalyst? [2] b) Does the pseudo steady state (time range of minutes) reaction rate increase with the chopping of the catalyst? [1] c) Why does the conversion stabilise at the end, despite the particle size still changing? [2] d) If you assume that the fragmented particles can be approximated as spheres, what is the dependancy between kc (m/s) and particle size (note that the correlation given in the slides is for packed beds only!). [6] e) Estimate the what the initial (pseudo steady state) conversion would have been if 5g of 1.5mm spherical particles were used (same amount of active sites per area as the 3mm spheres).[5] Question 9 (Q3 2008 E) [17] The second order reaction A -> B+C occurs in the liquid phase in a CSTR. Initially 5 grams of solid 3mm spheres (solid density of 1200 kg/m 3 ) are suspended in 5 liters of liquid. Although the spheres are non-porous, active sites are embedded within the solid matrix. The volume remains constant while a continuous flow of 100 l/min of pure A at 6 mol/l is fed to the CSTR. Steady state is achieved within minutes, but it was noticed that there is a gradual increase in conversion over the 2 day period of the run. Closer examination of the mixture showed a gradual chopping action of the impeller on the catalyst, resulting in a decrease in the average particle size: You can assume that the ‘surface active site concentration’ (sites per area) are the same for all the particle sizes, and further approximate all particles as spheres. The area based intrinsic rate constant is given as 2.4e-5 m 4 /mol/s. The following results are available: u Ti me ( hours) dp ( m) conversion % 0. 1 3000 13. 2 24 990 36. 3 45 100 79. 2 a) Does the active area of the catalyst increase with the chopping of the catalyst? [2] b) If we assume that external mass transfer has no influence on any particle diameter, determine the expected conversion at times 0.1, 24 and 45 hours. [4] c) For which particle size is mass transfer the most significant? [1] d) Using the measured conversions, determine the specific mass transfer coefficient (kc with units m/s) for the given particle diameters. Clearly indicate the equations with corresponding units that you use to solve for kc (draw a box around these equations and units). [7] e) What is the dependency between kc and dp? [3] Question 10 (Q1 2009 E) [10] An isothermal run on the liquid phase decomposition of component A is performed in a CSTR containing a spinning catalyst basket. A conversion of 27% is obtained. Details on the reactor are given below. It was shown that an increase in the stirrer speed has no influence on the conversion. The apparent order of the reaction was determined to be second order. Catalyst radius (R) 2 mm Mass of catalyst in basket 4 kg Inlet flowrate to reactor (Q) 1 l/s Inlet concentration of A 2000 mol/m3 Catalyst effectivie diffusivity 5.0E-09 m2/s Catalyst density 1600 kg/m3 a) Should external mass transfer be considered ? [1] b) What is the external surface concentration on the catalyst? [1] c) In what regime is the catalyst operating in? Remember to check units! [2] d) What will be the true order of the reaction? [1] e) What is the intrinsic rate constant (with units)? [2] f) If the catalyst is ground to a very fine powder and we assume that there will be no internal mass transfer effects (or catalyst losses from the reactor), what conversion will be achieved in the reactor? [3] Question 11 (Q3 2009 E) [13] The following elementary reaction: D C B A + ÷ + is studied in an adiabatic CSTR as well as a cooled/heated CSTR (via a coil containing a constant temperature utility). The following specifications are given: Inlet temperature (both reactors) 300 K Heat of reaction based on A (exothermic) -50 kJ/mol Molar flowrate of A to both reactors 20 mol/s UA in cooled/heated CSTR 5000 W/K p @100% conversion 500 K Constant utility temperature 420 K The molar heat capacities of all the components are the same. A stoicheometric ratio of A and B is fed to both reactors. a) Given an outlet temperature of 400 K, which of the two reactor schemes will result in the highest conversion of B? [6] b) What is the outlet temperature of the cooled/heated CSTR for a 100% conversion. Clearly explain why this is different from that of the adiabatic reactor? [3] c) At what conversion will both reactor schemes have the same outlet temperature? Why do both reactors behave the same at this point? [4] Question 12 (Q4 2009 E) [16] The following liquid phase first order reaction: E B A + ÷ Is studied in two different shaped packed bed reactors (see reactor A and reactor B in table below). Reactor A inside diameter 20 mm Reactor B inside diameter 86 mm Mass of catalyst loaded (RX A&B) 200 gram Bed porosity ( H) 0.4 Inlet liquid flowrate 25 liter/hour Liquid density (r L ) 800 kg/m3 Catalyst A diameter (d p ) 2 mm Catalyst B diameter (d p ) 4 mm Viscosity of liquid (m) 5.0E-04 kg/ms Pellet effectivie diffusivity (A&B) 4.0E-09 Pellet density (A&B) 1600 kg/m3 Spherical catalyst A is used in reactor A and a conversion of 96.7% is obtained. Spherical catalyst B is identical to catalyst A except in pellet size. You can assume that external (liquid-solid) mass transfer is negligible for all the runs. You can also use the following correlation to estimate axial dispersion: u p c L p p p u d with e ud D p = = ÷ Re 8 . 1 Re 0013 . 0 a) What will be the conversion for reactor B if 200 g of Catalyst A is used? [5] b) What will be the conversion for reactor A if 200 g of Catalyst B is used? [5] c) What will be the conversion for reactor B if 200 g of Catalyst B is used? [6] How will it change for the packed bed in (2). 1. What will be the conversion if 2mm particles are used. The conversion is 80% if 1mm particles are used. if one assumes that internal mass transfer is controlling the rate for both particle sizes? mass transfer is controlling the rate for both particle sizes? 3. What will be the conversion if 2mm particles are used. if one assumes that external .Question 2 (2003 Q3 E) [10] A first order liquid reaction occurs in a packed bed reactor. [2] [4] [4] 2. If the shape of the packed bed is changed so that the reactor is longer and the diameter smaller (the same amount catalyst is used). how will the conversion change for the 2mm packed bed in (1). 5 5 Particle size (mm) 0. (g/l) 3 8.s-1 ) is directly proportional to the conversion of A for a given inlet flowrate and reactor volume.4 0. The following results were obtained for 3 different runs where only the catalyst concentration and size were varied. while the volumetric amount of gas in the liquid phase (gas holdup) remains the same. What will be the conversion in the reactor if 0.2mm particles are used at a concentration of 4 g/l together 3.3 1.1 mm particles are used at a concentration of 4 g/l? with the improved sparger. Does external (liquid to solid) or internal mass transfer influence the reaction rate? . Pure B is fed in complete excess to the sparger at the bottom of the reactor. [6] What will be the conversion if 0. By using a different sparger in the same reactor. Pressure (bar) 10 10 10 Conversion of A 0. Prove that the volumetric reaction rate -rA (mol.1 0.1 0.Question 3 (Q4 2003 E) [22] A range of experiments were performed in a continuous slurry reactor where the following reaction occurs: A(l ) B ( g ) D (l ) The reaction is first order with respect to B in the liquid phase and zero order with respect to A.l-1. Does gas to liquid mass transfer influence the reaction rate? [2] [4] [6] 4.65 0.5mm. the average bubble size decreases from 3mm to 1. 2. Pure A is fed as liquid and a mixture of A and D flows as liquid out of the reactor.27 Catalyst conc. what would the conversion-reactor length profile look like? Draw a qualitative sketch. Explain the methodic that you would use to determine the single amount of catalyst that will give you the same conversion in an adiabatic PFR and adiabatic CSTR. [3] c) If the reaction occurred in an adiabatic CSTR with an inlet temperature of 55°C. [2] b) If the reaction occurred in an adiabatic PFR with an inlet temperature of 55°C. Neatness will earn you extra marks! [4] d) For the reactors in (b) and (c). What practical considerations will cause the cooling to be more? [4] [6] f) Assume the reaction was endothermic. What is the conversion? e) Estimate the minimum amount of cooling (in kW) required to obtain a 90% conversion. unlike a PFR where we just increase the length to obtain the next point on the profile).Question 4 (Q2 2005 T1) The following reversible exothermic reaction is studied in the liquid phase: ABC [22] Figure 1 gives the necessary rate detail for this reaction for a given feed concentration. when the feed temperature is 80°C. The following information is also supplied: CpA= CpB= 125 : Heat capacities (kJ/kmolK) H = -20000 : constant heat of reaction (kJ/kmol A) Q = 2000 l/min a) If the reaction occurred in an isothermal PFR at a temperature of 55°C. what would the conversion-reactor size profile look like? Draw a qualitative sketch with some numerical pointers. Draw a qualitative sketch with some numerical pointers on the sketch in (b). what would the conversion-reactor size locus look like? (Note that a locus implies that we use a separate size CSTR for each point on the locus line. estimate the single amount of catalyst that will give you the same conversion in a PFR and CSTR. [3] . . Question 5 (Q3 2005 E) [20] The first order irreversible liquid phase reaction (A->B) is studied in an adiabatic CSTR and an isothermal PFR with similar feeds (flowrate and concentration). If the catalyst size in the PFR is 3mm at what temperature should the PFR be operated? [5] 3. If the operating temperature of the PFR is 250°C. Non ideal flow effects and external mass transfer can be neglected in this problem. will the rate be monotonically decreasing or not? [5] . If a adiabatic PFR was used with an inlet temperature of 250°C. This can be done by varying the particle size in the PFR or the operating temperature of the PFR. what size catalyst should be used? [10] 2. Information of CSTR: Catalyst diameter 1mm Inlet temperature .200°C Information on the reaction Reaction enthalpy – -25 kJ/mol (exothermic) Heat capacity of A – 125 J/mol/K Activation energy on catalyst – 50kJ/mol Effective diffusivity of catalyst – 7e-8 m2/s Catalyst density – 2500 kg/m3 Inlet flowrate – 10 l/s Mass of catalyst – 10 kg 1. The idea is to obtain the same conversion in the PFR using the same amount of catalyst. The CSTR conditions (catalyst size and inlet temperature) remains the same and are specified below. The CSTR achieves a 80% conversion. [6] .kg-1s-1. while the inlet conditions remain the same (same amount processed). Is the effectiveness factor a function of length for this example? Give the [3] effectiveness factor at the entrance and exit conditions of the first run (length =L) [2] 3. what will be the conversion if the 2L reactor is used? You can assume that the Particle Reynolds number for all the runs (1-3) are below 20. The intrinsic rate constant is known to be 0.5 l. In the second run the reactor is length is doubled (2L). Information of packed bed reactor: Effective diffusivity of catalyst .Question 6 (Q2 2005 E) [21] The first order irreversible liquid phase reaction (A->B) occurs in a packed bed reactor where external mass transfer is negligible.1e-7 m2/s Catalyst diameter .9% is obtained. What will be the conversion in the second run (2L)? [10] 4.2mm Catalyst density 2000 kg/m3 Volumetric flowrate – 2000 l/min Weight of catalyst 100 kg 1. A conversion of 54. If the catalyst size is halved (third run). What is the effectiveness factor of the catalyst? 2. According to the plant engineer the old CSTR was very stable in its operation and he is concerned about the reactor with the new catalyst since. Catalyst concentration – 0.s. CPB – 100 J/molK The new catalyst has an activation energy of 50 kJ/mol. but due to a higher activation energy the activity of the catalyst is higher than that of the old catalyst above 200°C. The reactor performance should not alter from that of the old catalyst. It is further safe to neglect all mass transfer effects on the reaction rate. a) What was the conversion in the old CSTR? [4] b) What should be the concentration of the new catalyst in the reactor to achieve the same conversion? c) Any comments/suggestions on the stable operation of the reactor.25 g/l – negligible mass transfer effects CPA – 100 J/molK. as he puts it “CSTR’s are known for erratic behaviour”. The following is known about the reactor and old catalyst: First order reaction A->B Inlet temperature – 70°C Outlet temperature – 309°C Reaction enthalpy – 25 kJ/mol (exothermic) Pre exponential constant – 1000 l/g. [6] [7] . The new catalyst has the same activity as that of the old catalyst at 200°C. Activation energy 35 kJ/mol Inlet flowrate of pure A – 200l/min at 15 mol/l Reactor volume –400 l.Question 7 (Q2 2007 E) [17] You are approached to re-design an existing adiabatic CSTR due to the development of a new catalyst. Closer examination of the mixture showed a gradual chopping action of the impeller. The volume remains constant while a continious flow of 100 l/min of pure A at 6 mol/l is fed to the CSTR.529 0. but it was noticed that there is a gradual increase in conversion over the 2 day period of the run.605 0. despite the particle size still changing? [2] d) If you assume that the fragmented particles can be approximated as spheres. [6] e) Estimate the what the initial (pseudo steady state) conversion would have been if 5g of 1. Steady state is achieved within minutes. Initially 5 grams of solid 3mm spheres (solid density of 1200 kg/m3) are suspended in 5 liters of liquid.627 0.645 0.637 0.Question 8 (Q2 2008 T2) [16] The second order reaction A -> B+C occurs in the liquid phase in a CSTR. resulting in a decrease in the average particle size: The following measurements were reported: Time running (hours) 0.648 a) Does the active area of the catalyst increase with the chopping of the catalyst? [2] b) Does the pseudo steady state (time range of minutes) reaction rate increase with the chopping of the catalyst? [1] c) Why does the conversion stabilise at the end.5mm spherical particles were used (same amount of active sites per area as the 3mm spheres). what is the dependancy between kc (m/s) and particle size (note that the correlation given in the slides is for packed beds only!).[5] .1 6 12 20 30 60 Average particle diameter (mm) 3000 990 520 300 140 80 Conversion 0. 1 24 45 dp (m) 3000 990 100 conversion % 13.Question 9 (Q3 2008 E) [17] The second order reaction A -> B+C occurs in the liquid phase in a CSTR. Closer examination of the mixture showed a gradual chopping action of the impeller on the catalyst. e) What is the dependency between kc and dp? [7] [3] .2 a) Does the active area of the catalyst increase with the chopping of the catalyst? [2] b) If we assume that external mass transfer has no influence on any particle diameter. active sites are embedded within the solid matrix.1. and further approximate all particles as spheres. The area based intrinsic rate constant is given as 2. but it was noticed that there is a gradual increase in conversion over the 2 day period of the run. determine the specific mass transfer coefficient (kc with units m/s) for the given particle diameters.3 79. 24 and 45 hours. Steady state is achieved within minutes. determine the expected conversion at times 0. resulting in a decrease in the average particle size: You can assume that the ‘surface active site concentration’ (sites per area) are the same for all the particle sizes.4e-5 m4/mol/s. The volume remains constant while a continuous flow of 100 l/min of pure A at 6 mol/l is fed to the CSTR. Although the spheres are non-porous. Clearly indicate the equations with corresponding units that you use to solve for kc (draw a box around these equations and units). Initially 5 grams of solid 3mm spheres (solid density of 1200 kg/m3) are suspended in 5 liters of liquid. The following results are available: Time (hours) 0. c) For which particle size is mass transfer the most significant? [4] [1] d) Using the measured conversions.2 36. Catalyst radius (R) Mass of catalyst in basket Inlet flowrate to reactor (Q) Inlet concentration of A Catalyst effectivie diffusivity Catalyst density 2 mm 4 kg 1 l/s 2000 mol/m3 5. what conversion will be achieved in the reactor? [3] . Details on the reactor are given below. A conversion of 27% is obtained. It was shown that an increase in the stirrer speed has no influence on the conversion.0E-09 m2/s 1600 kg/m3 a) Should external mass transfer be considered ? b) What is the external surface concentration on the catalyst? c) In what regime is the catalyst operating in? Remember to check units! d) What will be the true order of the reaction? e) What is the intrinsic rate constant (with units)? [1] [1] [2] [1] [2] f) If the catalyst is ground to a very fine powder and we assume that there will be no internal mass transfer effects (or catalyst losses from the reactor).Question 10 (Q1 2009 E) [10] An isothermal run on the liquid phase decomposition of component A is performed in a CSTR containing a spinning catalyst basket. The apparent order of the reaction was determined to be second order. Question 11 (Q3 2009 E) The following elementary reaction: A B C D [13] is studied in an adiabatic CSTR as well as a cooled/heated CSTR (via a coil containing a constant temperature utility). which of the two reactor schemes will result in the highest conversion of B? [6] b) What is the outlet temperature of the cooled/heated CSTR for a 100% conversion. A stoicheometric ratio of A and B is fed to both reactors. The following specifications are given: Inlet temperature (both reactors) Heat of reaction based on A (exothermic) Molar flowrate of A to both reactors UA in cooled/heated CSTR p @100% conversion Constant utility temperature 300 K -50 kJ/mol 20 mol/s 5000 W/K 500 K 420 K The molar heat capacities of all the components are the same. a) Given an outlet temperature of 400 K. Clearly explain why this is different from that of the adiabatic reactor? c) At what conversion will both reactor schemes have the same outlet temperature? Why do both reactors behave the same at this point? [4] [3] . You can assume that external (liquid-solid) mass transfer is negligible for all the runs.0E-09 1600 kg/m3 Spherical catalyst A is used in reactor A and a conversion of 96.0E-04 kg/ms 4. You can also use the following correlation to estimate axial dispersion: D 0.4 25 liter/hour 800 kg/m3 2 mm 4 mm 5.8e ud p p with Re p d p u L a) What will be the conversion for reactor B if 200 g of Catalyst A is used? [5] b) What will be the conversion for reactor A if 200 g of Catalyst B is used? [5] c) What will be the conversion for reactor B if 200 g of Catalyst B is used? [6] .Question 12 (Q4 2009 E) The following liquid phase first order reaction: A BE [16] Is studied in two different shaped packed bed reactors (see reactor A and reactor B in table below).0013 Re 1. Reactor A inside diameter Reactor B inside diameter Mass of catalyst loaded (RX A&B) Bed porosity ( ) Inlet liquid flowrate Liquid density (r L ) Catalyst A diameter (d p ) Catalyst B diameter (d p ) Viscosity of liquid (m) Pellet effectivie diffusivity (A&B) Pellet density (A&B) 20 mm 86 mm 200 gram 0.7% is obtained. Spherical catalyst B is identical to catalyst A except in pellet size.