CHEMICAL ENGINEERING 4903-2 - University of Utahring/ChE 4903 Projects lab/Laboratory... · Web viewCHEMICAL ENGINEERING 4903-2 FALL SEMESTER – 2013 SCHEDULE OF LABORATORY EXPERIMENTS

CHEMICAL ENGINEERING 4903-2FALL SEMESTER – 2013 SCHEDULE OF LABORATORY

EXPERIMENTS(Revised 8/20/13)

Project Period IFormal Report

IIReport

IIReport

Receive Lab Assignment

8/28 9/26 11/7

Lab Prelim. Conference Deadline

9/3 10/1 11/12

Report Due (1:00 PM) 9/26 11/7 12/12

Technical Rewrite Due (1:00 PM) if necessary

One week after receiving instructor

graded report

One week after receiving instructor

graded report

None due

Group I Sean PetersonMichael YehMatt Houston

Shell & Tube Heat Exchanger-1

Extruder-2 Stirred Tank Reactor-3

Group IIWentao LiGustavo VieiralvesMariana de Castro

Stirred Tank Reactor-1

Ultrafiltration/Reverse Osmosis-2

Shell and Tube Heat Exchanger-3

Group IIISteve TaylorMitch BowlesHyunggu Han

Distillation Column-1

Shell & Tube Heat Exchanger-2

Liquid Level Control-3

Group IVJames AllenMatt OsmondEric Wheelwright

Fluidized Bed-1 Heat Conduction-2 Distillation Column-3

Group VDallon BoydTristalee Williams

Double-Pipe Heat Exchanger-1

Distillation-2 Fluidized Bed-3

Group VI Absorption Column-1 Liquid Flow Bench-2 Double-pipe Heat Exchanger-3


The shell and tube heat exchanger in the laboratory has not been used for several months. Beehive Engineering would like you to measure the fouling resistance in this unit so that it can be used for a new design. To measure the fouling resistance you will need to first determine the overall heat transfer coefficient for the transfer of heat from the jacket to the liquid inside the shell. The wall conduction and inside and outside heat transfer resistances must be determined by predictions so that they can be subtracted from the overall heat transfer coefficient leaving the fouling resistance. In this process, there are errors in experimental measurements and errors in the various predictions which will have an effect on the accuracy of the fouling resistance.

For your safety review meeting you will have to establish a protocol for these measurements and a dimensionless number correlation for the shell side and tube side heat transfer coefficient that is reasonable for this type of equipment. Note, your Reynolds numbers may not be in the fully turbulent range. Also be prepared to discuss the propagation of error in all of the calculations needed for this lab.

For you laboratory report, you should compare your experimental results for the inside and outside heat transfer coefficients with theoretical correlations to generated credibility for using them in determining the fouling resistance. The final report should also clearly report the fouling factor.

Finally using this fouling factor and this shell and tube heat exchanger determine the flow rate for SiH2Cl2 which enters as a vapor at it boiling point at 10 psig and is condensed and cooled to -55 C using Syltherm XLT as the coolant operating from -95C to -60C. seehttp://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_08a5/0901b803808a5a48.pdf?filepath=heattrans/pdfs/noreg/176-01468.pdf&fromPage=GetDoc

Please include this assignment in your report as an appendix but do not cite it in the body of your report.

http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_08a5/0901b803808a5a48.pdf?filepath=heattrans/pdfs/noreg/176-01468.pdf&fromPage=GetDoc



Vacuum Drying Oven –1

New technologies being investigated to protect a damaged space shuttle during reentry is to first fill the damaged area with a porous polymeric material and then soak it with water. At the temperatures of space the water will freeze in the pores. The worst-case scenario is for a 4 inch2 area, 1-inch deep hole in the shuttle’s skin. Your question is to determine if during reentry the shuttle’s skin will be protected by this ice filled repair. For your oral please present the external conditions present at the Shuttle’s skin during reentry. To help facilitate your investigations the laboratory has a vacuum drying oven that is steam heated. Professor Ring will supply several examples of the open cell porous polymer material to be tested. This material should be well characterized before it is to be used in your experiments.

Develop a series of experimental tests to determine the time required to remove water and ice from the porous structure at different drying conditions. Compare these measurements to predictions using simultaneous heat and mass transfer. Extrapolate these conditions to those of reentry of the space shuttle and predict if the ice filled repair material is adequate for this application. To do this effectively, you will need to simulate the temperature and pressure conditions that the shuttle will experience during reentry and then predict the rates of sublimation and drying that will take place in this patch material during these reentry conditions. Use risk analysis to determine what are the most important parameters that will lead to a successful patch of this type and determine what is the chance of failure of the patch during reentry. Astronauts’’ lives are riding on you work.



A client is running his CSTR without baffles and a top feeding location for both reactants. Both of these changes were done at the same time and now his reactor conversion is much too low. His engineer told him that the thermal well and feed tubes would provide sufficient mixing in this reactor so baffles were not needed. He wants to know which change is responsible for the low conversions being reported. The other operating conditions for the reactor are a total reactant flow rate of 100 mL/min, a reactor volume of 1.3 L and a Rushton impeller speed of 10 rpm. The reaction being performed in the reactor is the saponification of ethyl acetate with the reactants being fed at equimolar flow rates.

Uniform mixing of reactants is critical to the conversion in a CSTR. You are to develop a series of data and calculations to show the effect of residence time on reactor conversion for presentation to the client. Since the laboratory hoods are not functioning no chemicals with toxic vapors can be used so only residence time distributions and model calculations can be used to prove your point.

Please run a CSTR with and without baffles and with top and bottom feed locations to establish the degree of micro/macro-segregation that is observed as a function of stirring rate (1, 10, 100 rpm) using the residence time distribution as your test case. Start with an unbaffled tank and proceed to add baffles until four are added and do these measurements for top and bottom feed locations. Please determine the residence time distribution for each experimental condition. Compare the residence time distributions and the micro/macro-segregation models given in Chapt 14. of Fogler’s “Elements of Reaction Engineering” 2nd edition.

The client uses the saponification of ethyl acetate

Et-Ac + NaOH ↔NaAc + Et-OH

for his reaction. The kinetics of this reaction is reported in Hovarka, R.B. and Kendall, ;H.B. "Tubular reactor at low flow rates" CEP56(8),58-62(1960). In equimolar experiments they found this reaction to be second order overall. The kinetics provided by Hovarka and Kendall can be used for prediction purposes.

In your final report, use reactor-mixing models to fit the results you have obtained from measurements of the residence time distribution. Use your best mixing model and the reaction kinetics to predict the real reactor conversion and compare it to the ideal CSTR reactor conversion. So that we can show the client we can clearly predict the effects of poor mixing in his CSTR. Clearly identify which of the two changes, removal of baffles and top feeding, is responsible for the low conversion the client is experiencing in his/her saponification reactor.


Liquid Flow Bench-1

Flow through packed beds are essential for many unit operations including trickle bed reactors used for biological clean-up of phenol from process waters in a Salt Lake City refinery. Phenol at concentrations above 10 ppm is toxic to bacteria in waste water treatment facilities and must be removed before refinery waste water is discharged to the sewer. As a result, waste water is caused to flow through a packed bed bioreactor made of porous sand impregnated and bound with an enzyme from unique strain of bacteria that considers phenol food. The enzyme in the acid form catalyzes the oxidation of phenol rendering it non-toxic. The kinetics of this oxidation reaction follows the Michaelis Menton kinetic relation

-Rate = Vmax S/(Km+S)

where S is the concentration of the substrate, phenol, and Vmax =1 x10-6 mole/(cm2 hr) and Km= 12 ppm measured for the enzyme impregnated sand particles. Your job is to determine from the properties of the flow of water in the laboratory sand bed (i.e. friction factor vs Reynolds number) so that this sand bed can be used in an appropriate waste water treatment plant to treat 50 gal/hr of water loaded with 500 ppm phenol so that it can be rendered safe to send to the Salt Lake City sewer. Size (diameter and height) the sand bed reactor needed for this application.


Bubble-cap Distillation Column –1

Please operate the laboratory distillation column in two modes: 1) at total reflux and 2) when top and bottom products are being taken with a recycle ratio of approximately twice the minimum recycle ratio. Determine the overall and stage-by-stage efficiency of the laboratory distillation column under these two modes of operation. Please assure that the distillation column is operating at steady state before samples are taken for your analysis of the efficiency.

For your oral exam please predict the overall stage efficiency from a correlation available in the literature. For this calculation, assume that the column capacity is limited by flooding considerations and make your estimate of overall efficiency at 80% of flooding. Also be prepared to discuss errors in your experimentally measured quantities and error propagation of the overall stage efficiency determined. Which mode of analysis and operation will give the lowest errors?

An estimate is needed of the capacity (GPM of Feed) of the laboratory distillation column to process a 15% ethanol in water stream and to produce a 95% ethanol product. The approximate reflux ratio, the reboiler duty required, the optimum feed plate location and the expected percent ethanol recovery are to be specified.

You are to make this estimate based upon the results of operation of the same laboratory column on the water-isopropanol solution available. Necessary corrections to these laboratory data are to be made based upon standard correlations, to permit the evaluations needed for the ethanol-water system.


Fluidized Bed-1

Fluid bed reactors are used for many applications in industry from pulverized coal burning to catalytic crackers to silicon purification. Since there is excellent heat transfer in the fluid bed, coils are often inserted to heat or cool the bed allowing the reaction heat to be dissipated in exothermic reactions. Heat transfer and fluidization characteristics are different for different powders. A client has several powders (carbon, sand and glass beads) that need to be tested for their fluidization characteristics. The most important fluidization characteristic is that of the minimization fluidization velocity; the velocity of the gas just necessary to fluidize the powder. Please measure the minimization fluidization velocity for the client’s powders. Compare the minimization fluidization velocities to a correlation in Leva, (“Fluidization “ p. 63 McGraw-Hill, NY 1959). To make this comparison the particles in the powder must be characterized with respect to their density, particle diameter, and shape factor. In addition determine the bed expansion as a function of the pressure drop and compare these results for the various powders to those calculated using the correlation in Leva, Chapt 4.

Using the fluidization results for the client’s carbon sample design a fluid bed combustor for the reaction

C + O2 CO2

with the surface reaction rate given by Parker and Hottel (Ind. Eng. Chem. 28,1334,(1936))

Rate= ,

for 1 tonne/hr carbon combustion rate operating at 10% excess air at 1300K. Please note that you should also consider the rate of boundary layer diffusion as well as the surface reaction rate in the kinetic model used for design of the fluid bed combustor.


Spray Dryer-1

Our client’s spray dryer dries SiO2 suspensions to make a flowable SiO2 powder for the animal feed industry. Initially, the SiO2 particles are very small, i.e.98% < 325 mesh, so that they can react quickly. Unfortunately these silica particles flow poorly in clumps like flour which leads to poor distribution of SiO2 in portion to the animal feed in the mixture. The client’s application requires the SiO2 powder to flow more like sugar and for this reason it is to be spray dried to a larger particle size, where the particles now consist of a snowball like compacts of the very small particles, before it is added to the animal feed. For this laboratory, you need to determine the concentration of SiO2 in suspension that will give a flowable powder. You can be guided by calculations for flowable powders if you look at correlations for the droplet size distribution produced by atomization and considering that all of the water in the SiO2 suspension droplet will dry away leaving only a compact of SiO2 particles. Often a polymeric binder is used to hold the particles together in the compacts. Our client uses poly acrylic acid (Mw 5,000 gm/mole) at 0.1 wt. % in the aqueous solution, 6< pH < 10, used to make the suspension. Your task is to find spray drier operating conditions required to produce these particles with water contents less than 1%. To help you determine the drying conditions, you can determine the time it takes for a droplet formed at the nozzle to flow to the cyclone separator in the hot gasses of the spray dryer. This time must be just longer than the drying rate calculated by simultaneous heat and mass transfer drying to take place for the droplet size produced by the atomizer if drying is to be complete. You are to predict the drying conditions for complete drying of these droplets for your oral exam and compare these drying conditions with the your experimental water contents of the spray dried particles for operating conditions that are more and less severe than those calculated for complete drying. The reason for the differences between experiment and theory are to be explained quantitatively in your report.

In addition to the standard laboratory equipment available to you including a pilot scale spray dryer, you have at your disposal a microscope fitted with a camera and the software IMAGE J from the NIST.gov website which can perform particle size distribution measurements.

Additional questions you need to consider for the oral exam are: Why is a binder used for spray drying? Why is poly acrylic acid (PAA) used for a binder in the case of SiO2. What is so special about PAA? Why is the solution pH controlled to pH 6 - pH 10 for this application? You will also be required to quantitatively discuss the drying rate of a wet sphere of SiO2 particles and the operation of the spray dryer.

Do the various operating conditions used in spray drying alter the angle of repose measurements on the powder produced?


Glass Lined Reactor-1

The client needs a Heat transfer correlation for a glass-lined reactor of odd geometry. Using the glass lined reactor determine the heat transfer coefficient for the transfer of heat from the steam jacket to the liquid inside the reactor. Please make these measurements with the baffle in place at various liquid levels and stirring rates. For your oral exam you will have to establish a protocol for these measurements (including accuracy assessment) and a correlation (of the type Nusselt Number versus Reynolds number) that is reasonable for this type of equipment.

Based upon a reaction the saponification of ethyl acetate

Et-Ac + NaOH NaAc + Et-OH

determine a design for this glass-lined reaction using this reactor. The kinetics of this reaction is reported in Hovarka, R.B. and Kendall, ;H.B. "Tubular reactor at low flow rates" CEP56(8),58-62(1960). In equimolar experiments they found this reaction to be second order overall. This reaction conversion may be limited by either kinetics or heat transfer. Assuming 1 M feed of both reactants and a conversion of reactants to the product of 0.85, determine the capacity (kg/hr of NaAc that the glass-lined reactor can produce.


Heat Conduction-1

Your older car antenna made of shiny 304 stainless steel which is 0.6 cm diameter and 30cm tall is attached to your black car. The black car keeps the bottom of the car antenna at a constant temperature of 120C due to the car sitting in the sun on a sunny day. The air temperature is 28C and there is no wind blowing. You are to use the heat condition apparatus to perform experiments to determine an appropriate heat transfer coefficient for modeling purposes to make predictions of the temperature profile in your car’s antenna. Before proceeding to model the car’s antenna, it is necessary to verify that you have an accurate simulation by making comparisons with experiments performed on the aluminum, steel and stainless steel rods that are part of the heat conduction apparatus. These measurements should be made with the apparatus with rods in the horizontal and the vertical direction. Show the differences in rod orientation between the heat transfer coefficients measured. Does the rod’s vertical position make difference in the heat transfer coefficient that should be applied? After verifying the accuracy of the simulations with the rods in both positions proceed to the simulation of the car’s antenna. For the vertical position of the antenna determine the height above its base is the antenna 100C, the boiling point of water.

For the preliminary oral exam, be prepared to describe the apparatus, correlations for natural convection given various geometries, the appropriate equations that govern the conduction of heat down a rod that has radial heat transfer at is surface, methods of error analysis to be applied to all calculations performed in this laboratory report.


Gas Flow Bench-1

Most orifices used for flow measurement are used on liquids, or on gases with low pressure ratios, where the effect of change in gas pressure (and gas density) across the orifice is unimportant. Most of our laboratory experiments with orifices fall into this category. However there are some industrial situations in which orifice meters are used at high gas velocities where the change of gas density, its compressibility, must be taken into account. The most common method of doing this is shown on pages 5-10 to 5-14 of Chemical Engineers' Handbook 5th edition. The method shown there is almost certainly based on theory. The theory is proba.bly right. But I have never seen any experimental confirmation of it. Please set up an orifice meter in such a way that in its normal operation the value of the expansion factor (Y)will be significantly different from unity. Measure this factor over as wide a range of experimental values as practical. Compare your experimental values with those in Chemical Engineers' Handbook 5th edition or whatever other literature sources seem more appropriate. Explain the differences, if any.

Be prepared to discuss the potential safety hazards and how you intend to operate the experimental equipment safely at these high pressure drops.


Double Pipe Heat Exchanger-1

One technique for the determination of individual heat-transfer coefficients from heat exchanger data was originally suggested by E.E. Wilson many years ago. This method is described on page 345 of the book by W.H. McAdams, Heat Transmission 3rd Ed., McGraw-Hill Book Co. New York, N.Y. (1954).

(a) By use of this technique, you are to determine the water side heat-transfer coefficient at water velocities of 1, 2, 4 and 6 ft/sec in the double-pipe heat exchanger.

(b) Compare your measured coefficients to published correlations and explain any discrepancies in your report.

(c) Calculate the "dirt" coefficient (fouling factor) for the heat-exchanger tube by assuming that the steam side coefficient can be calculated by use of the Nusselt equation for film-type condensation. Compare these measured "heat-transfer coefficients for deposits" to published data (see Perry’s Chemical Engineers Handbook 5th edition, p. 10-38-39 (Table 10-9 and 10-10) and comment on the relevance of your results in your report.


Absorption Column-1

Operate the packed absorption column in the Chemical Engineering Laboratory to absorb C02 from a gas stream with water. Determine, for each of the packed columns, the number of transfer units and height of a transfer unit for C02 absorption. The group who operated the packed columns during the previous laboratory period was unable to close the material balances. The principal problem seemed to be obtaining reliable flow rate information for the air and water streams; it appears, therefore, that the air and water flow meters should be calibrated before you begin.

Be prepared in your oral quiz to derive the equations governing absorption in a packed column and present your experimental plan including how you propose to make a feed stream containing C02 and the concentrations you propose to employ. Discuss the measurements required, what analytical procedures you will use to determine C02 concentrations in the air and water streams, and how the data will be analyzed to determine the information requested.

Be prepared in your oral quiz to address the following:a) Safety issues with this experimentb) Equipment operationc) Data sheetsd) Other germane points with respect to this experiment


Extruder-2

A client has produced a new high-density form of a polyethylene. We have been asked to characterize the extrusion properties of this new polymer and make predictions of its rate of extrusion in industrial equipment. The client also wants to know what is the maximum extrusion rate for the high-density polyethylene polymer in the manufacture of a new type of 1” pipe to replace that, which is sold for sprinkler systems here in the USA. The industrial equipment used today extrudes PVC at 10 C above its melting point at 0.5 m/s through the 1” pipe die. You have PVC, the blue beads in the laboratory, which you can try for comparison purposes to characterize the rheology of PVC for comparison purposes.

Your boss believes the best way to do this is to measure the Non-Newtonian rheology of the polymer at various temperatures and then to extrude it under various conditions to verify that it can be extruded well. So at various temperatures, perform extrusion experiments at various temperatures and flow rates. Measure the pressure and the flow rate for these conditions. Using appropriate Newtonian models for the flow in both an extruder and a rectangular die1 calculate the viscosity of the fluid. Plot the viscosity as a function of shear rate. Is the viscosity Newtonian? Please identify any Non-Newtonian data taken. What rheological equation should be used to fit the Non-Newtonian data? How is the PVC different from the high-density polyethylene?


1 Ring, T.A. “Fundamentals of Ceramic Processing and Synthesis” Academic Press, New York 1996, p. 644-649.

Gas Flow Bench -2

Use the gas flow bench to determine the friction factor for air flow in pipes. Of particular interest is the turbulent regime where the pipe roughness plays a role. Carefully plan your experiments to obtain the most accurate measurements of the friction factor and the Reynolds number. For your preliminary laboratory conference please give the range of flow rates, pipe sizes, pressure drops and other parameters you intend to use. In addition please predict the range of Reynolds number to be investigated as well as the accuracy of the friction factor to be measured. Compare your results with those in the literature and discuss any differences.

With this data and any experimental correlations developed, please design a pipeline to pump natural gas from the Vernal, UT to North Salt Lake City. Please consider the major elevations gains and friction losses to place the various pumping stations along the route. Consider the pipeline to take a line of sight route.


Ultrafiltration/Reverse Osmosis-2

Great Salt Lake Minerals has a brine that consists of 30% wgt MgCl2 and 1.5% wgt NaCl. It is suggested that ultrafiltration can be used to make the separation between the different salts in the brine.

Using the laboratory ultrafiltration/reverse osmosis unit and membranes provided determine the conditions of pressure, flow rate and temperature that gives the largest purification. Be particularly aware that membrane fouling caused by increased solute concentration at the membrane surface causes concentration polarization which decreases permeate flux.

To start this project you will need to develop analytical methods to measure the concentration of Na and Mg ions in solution. You boss thinks Atomic Absorption sepectroscopy can be used. Dana Overracher is an expert on this instrument.

Use the best experimental conditions to design an ultrafiltration/reverse osmosis unit for this aqueous solution to process 1,000 gallons per day for the client. Using the concentration polarization results determine the lifetime of the membrane for this application. Determine the cost for membrane replacement as well as the pumping costs over the course of 1 year’s operation giving a cost per million gallons of water produced.


Glass Lined Reactor -2

The client needs a heat transfer correlation for a glass-lined reactor of odd geometry. Using the glass lined reactor determine the heat transfer coefficient for the transfer of heat from the cooling water jacket to the liquid inside the reactor. Please make these measurements with the baffle in place at various liquid levels and stirring rates. For your oral exam you will have to establish a protocol for these measurements (including accuracy assessment) and a correlation (of the type Nusselt Number versus Reynolds number) that is reasonable for this type of equipment. The client has a confidential reaction to be run in the glass lined reactor operated in semi-batch mode. Reactant A is placed in the reactor filling the reactor to ½ full and reactant B is added slowly until an equimolar mixture has been fed to the reactor. This confidential reaction is exothermic with a heat of reaction of -44 kcal/mole and a second order rate constant given by:

with an activation energy of 15 kcal/mole. Using the heat transfer coefficient you have measured as a function of the liquid level in the reactor, the reaction kinetics given above and the reactor dynamics expected determine the highest temperature the reaction mixture will reach during the reaction.

Please include this assignment in your report as an appendix, but do not cite it in the body of your report.


The client has a heat transfer application for the shell and tube heat exchanger that operates in the transition from laminar to turbulent flow. Your much older boss has suggested that you could use the 1934 Hausen equation to fit experimental data for the tube side heat transfer coefficient that you will be taking for the client. You are skeptical as your more modern heat transfer book by M. N. Ozisik suggests several equations including: Petukhov equation, Notter and Sleicher equation, Sieder and Tate equation and the Dittus and Boelter equation. Develop an experimental protocol to determine which of these equations is the best in fitting the tube side heat transfer coefficient for the shell and tube heat transfer coefficient in the lab. Please be concerned about the error analysis when you do the experiments and the data reduction calculations are performed as it may impact the choice of equation you select for the best fit. Your boss also suggests that you may have an entrance length that should be accounted for separately. To appease him please do an entrance length calculation in your report to assure that neither the momentum nor the heat transfer entrance length are important to the heat transfer analysis you are performing in the laboratory report.

The following is text from p. 10-14 in Perry’s 5th describing the 1934 Hausen’s equation.


Heat Conduction-2

A long cylindrical antenna on an airplane’s exterior cools it’s cylindrical aluminum electronics compartment to which it is attached. If the electronics are cooled to less than 0C then they will not work properly due to a surface acoustic wave transducer. The flight conditions are up to 8 hrs at 10,000 m altitude where the ambient temperature is –60C and with airspeed of 1,000 km/hr. You are to develop a model for the temperature distribution in the antenna and the cooling of the electronics compartment. The dimensions and materials of construction for the antenna and the electronics compartment are to be taken from the Heat Conduction experimental apparatus with its cylindrical steam chamber and its cylindrical metal rods in aluminum and stainless steel of various diameters. As part of your oral exam you will be required to predict the temperature transient profile for an aluminum rod as a function of time and location from one end where the temperature is held constant. You are to compare this model with measurements done on the Heat Conduction experimental apparatus in which you will monitor the transient heat conduction in the rods given an inlet of hot fluid at one end of the rods. In your final report compare the experimental transient temperature profile to the predicted transient temperature profile for all rods on the apparatus. Explain any differences you see between experiment and prediction in the discussion part of your report. Finally using this data and other materials and models, make suggestions for the materials of construction of the antenna for the airplane, its diameter (assuming it has to be of a given length to work as an antenna) and the heating requirements for a heater to be placed in the electronics compartment to provide the needed heat to keep the compartment at or above 0°C during the flight.



Our client has a CSTR saponification reactor operating in their plant. The saponification reaction used by our client is the saponification of ethyl acetate, (ET-Ac);


followed by a separation process for sodium acetate, NaAc, from the mixture of the solvent water and the reaction byproduct ethanol (ET-OH). They are having trouble with the reactor and want to increase the reactor’s yield. They have available a PFR that could be used in series or parallel to increase the reaction yield. First of all, they would like to know if their stirred tank reactor is operating as an ideal reactor. They think that the impeller operating at 30 rpm may be too slow for ideal mixing. You will be required to develop a method of experimentally determining if the reactor is operating ideally and specifically determine just how far from ideal this behavior is. Second of all, they would like to know how to configure the CSTR and PFR combination for and increase in yield for the saponification of ethyl acetate. You are to make the prediction of what is the best configuration before the oral exam using data from the literature2 that may take some further analysis and the geometry of the 1.3 Liter CSTR and the 63 cm long 2.5 cm in diameter packed bed PFR filled with 3 mm diameter glass bead packing located in Lab F which will be available to you for experimentation. Your laboratory work should make measurements on this reactor configuration and compare the experimental results with your predictions.

A key factor in these experiments is the method used to measure the concentration of either reactants or products from the reactor. Develop an accurate method of chemical analysis. What size sample do you need to take from the reactor to give accurate analysis?


2 Hovarka, R.B. and Kendall, ;H.B. "Tubular reactor at low flow rates" CEP56(8),58-62(1960).

Spray Dryer – 2

The client wants to develop a new product - a fragrant powdered starch. The client thinks that this type of product can be made by mixing a fragrance with water and starch. Our laboratory chemist has pointed out that the fragrances of interest to the client are all essential oil and as such will have some trouble solubilizing in water. He suggests that the fragrance/water mixtures can be obtained by adding a small amount (1% by weight) surfactant (liquid dish soap) and agitation. Adding a surfactant breaks the two phase (oil/water) mixture and creates an oil/water emulsion. The oil/water emulsion can now be used to solubilize the fragrance and mix this with the source of starch which is then to be spray dried into the desired fragrant powdered starch product.

Your task is to find spray drier operating conditions in order to produce this powder with water contents less than 1%. To help you determine the drying conditions, you can determine the time it takes for a droplet formed at the nozzle to flow to the cyclone separator in the hot gasses of the spray dryer. This time must be just longer than the drying rate calculated by simultaneous heat and mass transfer drying to take place for the droplet size produced by the atomizer if drying is to be complete. You are to predict the drying conditions for complete drying of these droplets for your oral exam and compare these drying conditions with the your experimental water contents of the spray dried powder for operating conditions that are more and less severe than those calculated for complete drying. The reason for the differences between experiment and theory are to be explained quantitatively in your report.

For the oral exam you will also be required to quantitatively discuss drying of a wet sphere of starch and the operation of the spray dryer.

An additional concern of the client is the angle of repose of the powder so do the various operating conditions used in spray drying alter the angle of repose of the powders produced.


Absorption Column-2

It is necessary to develop a correlation for the onset of flooding for different liquid flow rates and a correlation for the effective wetted area (per unit volume) as a function of gas and/or liquid flow rates. Set up experiments to measure the onset of flooding and the effective wetted area as a function of the experimentally available range of gas and liquid flow rates. Compare your correlations to those available in the literature.



Design an experiment to measure the inside film coefficient* for the double pipe heat exchanger as a function of the flow rate and other important parameters.

Determine the fractions of the resistance to heat transfer that can be attributed to the outside surface, the pipe wall, and the inside surface of the inner pipe. From your data, prepare estimates for these fractions and estimate, also, the extent to which the outside wall of the inner pipe is fouled.

In your report, present, in addition to the information asked above, suggestions, based on your experience in the project, for improving the heat transfer rate for this equipment.

*Hint: using Wilson plot of the data to determine inside film coefficient


Distillation-2

Compare Bubble-cap Distillation with packed bed distillation efficiencies. With the bubble-caps in place determine the overall stage efficiency from the top and bottom composition for the distillation column running in two modes: 1) at total reflux and 2) when top and bottom products are being taken with a recycle ratio of approximately twice the minimum recycle ratio. Compare the overall efficiency measured to that predicted by various correlations. Change out the bubble-caps for the packed bed and run the distillation column again in two modes: 1) at total reflux and 2) when top and bottom products are being taken with a recycle ratio of approximately twice the minimum recycle ratio determining the top and bottom composition. From the data determine the height of an equivalent tray for the packing (HETP). Compare the HETP measured to that predicted by various correlations. The major objective of your projects is to determine which distillation column internals should be used for the most efficient column operation?

With the most efficient column internals predict the maximum throughput for the laboratory column for the separation of a 5% ethanol solution with a recovery of 99% of the ethanol in a 75mole % ethanol distillate.


Liquid Flow Bench-2

Use the liquid flow bench to determine the friction factor for water flow in pipes. Of particular interest is the turbulent regime where the pipe roughness plays a role. Carefully plan your experiments to obtain the most accurate measurements of the friction factor and the Reynolds number. For your preliminary laboratory conference please give the range of flow rates, pipe sizes, pressure drops and other parameters you intend to use. In addition please predict the range of Reynolds number to be investigated as well as the accuracy of the friction factor to be measured. Compare your results with those in the literature and discuss any differences.

With these experimental correlations, please design a pipeline to pump oil with a viscosity of 1,000 cp at pipeline temperatures from the Vernal, UT to North Salt Lake City. Please consider the major elevations gains and friction losses to place the various pumping stations along the route. Consider the pipeline to take a line of sight route.


Stirred Tank Reactor – 3

Our client has a CSTR saponification reactor operating in their plant. The saponification reaction used by our client is the saponification of ethyl acetate, (ET-Ac);


followed by a separation process for sodium acetate, NaAc, from the mixture of the solvent water and the reaction byproduct ethanol (ET-OH). They are having trouble with the reactor and want to increase the reactor’s yield. First of all, they would like to know if their stirred tank reactor is operating as an ideal reactor. They think that the impeller operating at 3 rpm may be too slow for ideal mixing. You will be required to develop a method of experimentally determining if the reactor is operating ideally and specifically determine just how far from ideal this behavior is. Your laboratory work should make measurements on reaction conversion and compare the experimental results with your predictions.

A key factor in these experiments is the method used to measure the concentration of either reactants or products from the reactor. Develop an accurate method of chemical analysis. What size sample do you need to take from the reactor to give accurate analysis?


Heat Conduction-3

Monitor the transient heat conduction in the rods given an inlet of hot fluid at one end of the rod. Compare the experimental temperature to that predicted for the temperature transient at various distances down the rod. As part of your laboratory preliminary conference, develop the equations you will be required to use to predict the temperature transient profile for an aluminum rod as a function of location from one end where the temperature is held constant by condensing steam to the other. For your final report, you should do this prediction assuming 1) that the rod was one dimensional (length) and 2) that the rod was two dimensional (length and diameter). In this latter simulation, Comsol is suggested as the software of choice.



A client is interested to know the reason for the transient in his shell and tube heat exchanger. So you are to measure it and determine why it is so long. In addition, he wants to use this heat exchanger for two new uses, which require you to make design calculations for him.

Using the shell and tube heat exchanger determining the overall heat transfer coefficient for the transfer of heat from the jacket to the liquid inside the shell. For your oral exam you will have to establish a protocol for these measurements and a dimensionless number correlation for the shell side heat transfer coefficient that is reasonable for this type of equipment. Note, your Reynolds numbers may not be in the fully turbulent range. Compare your experimental correlation with any that are available in the literature.

In addition, you need to pay particular attention to data taken at startup of the equipment and develop a method of determining the effective thermal mass of the shell and tube heat exchanger experimentally which is the reason for the long transient. Compare that with an estimate of the mass using its geometry and the density of its various materials of construction.

In your final report you are to use the experimental data and analysis performed to develop a design of the operating conditions necessary to use this same shell and tube heat exchanger to cool both a mixture of 0.33 mole fraction dodecane in heptane from 300C to 50C and liquid sodium from 300C to 150C using cooling water in both cases. How much mixture can be fed to this particular heat exchanger per unit time and what flow rate of cooling water is needed. Assume that the cooling water is the same temperature as available in the tap in the Laboratory.


Heat Control -3

The heat control is an apparatus with a long residence time which makes developing a controller for it a time consuming operation. As a result, you should plan a limited experimental program to be used for process modeling purposes. Using control station fit the experimental data to a process model. Use the process model to develop two controllers be they P, PI, PD or PID and determine the appropriate coefficients for the two best controllers. After you have developed the controllers using control station implement the controllers on the heat control apparatus and test your two controllers. Compare the accuracy of the two best controllers on the apparatus to those same controllers on the process model. Develop a method to quantitatively compare the various controller types you have performed experiments upon. Be prepared to discuss the quantitative comparison method in the oral exam.


Liquid Level Control-3

The liquid level control experiment measures the pressure head in a tank and controls either the inlet flow rate or the outlet flow rate from the tank. The object of this experiment is to test both system configurations with a controller (either P,PI or PID) with an optimized set of tuning parameters. Determine which configuration is the best, to control level in the tank. You are also to specify the controller type(e.g. P,PI,PID) and optimum tuning parameters for the system, which best controls level by manipulations of the flow rate in or out of the tank. Develop a method to quantitatively compare the various controller configurations (various controller types) you have performed experiments on. Be prepared to discuss this quantitative comparison method in the oral exam.


Distillation-3

The bubble cap distillation unit has to be tested and compared to McCabe-Thiele theory of operation. To do this the column must be operated at a constant reflux ratio with product streams being continuously taken from the top and bottom of the unit. Develop a system to continuously remove fluid from the reboiler while making sure that the liquid level in the reboiler keeps the heating coils wet with fluid. Run the apparatus at steady-state at 1.3 time minimum reflux ratio and determine the top and bottom composition to test the theory. During this run take samples from all try locations to determine the stage efficiencies. In your final report, make a direct comparison between the McCabe-Thiele theory predictions with the individual stage efficiencies accounted for and your experimental results.


Extruder-3

Note, the die needs to be changed for this experiment to the ribbon die.

Perform extrusion experiments at various temperatures and flow rates. Measure the pressure and the flow rate for these conditions. Using appropriate Newtonian models for the flow in both an extruder and a rectangular die3 calculate the viscosity of the fluid. Plot the viscosity as a function of shear rate. Is the viscosity Newtonian? Please identify any Non-Newtonian data taken. What rheological equation should be used to fit any Non-Newtonian data?

Use the data gathered for polyethylene and validation of the various governing equations used, predict this equipment’s maximum extrusion rate for a ceramic paste consisting of 55% wgt. solids mono-disperse 0.1 micron diameter particles of amorphous SiO2 in water assuming that the Silica dispersion follows a Crossian or shear thinning rheology4 similar to polyethylene. Does the Braybender motor have sufficient torque to push the ceramic paste through the die (only) at this maximum flow rate?


3 Ring, T.A. “Fundamentals of Ceramic Processing and Synthesis” Academic Press, New York 1996, p. 644-649.4 Ibid, p. 562-573.

Liquid Flow Bench-3

A client uses beds of sand to filter impurities out of various chemicals. He now wishes to use one bed of sand· for several chemicals, in block operation. (That is Chemical A for one week, Chemical B for the .second week, then back to Chemical A.) The key to successful operation of this system is the quantity of chemicals which must be discarded due to contamination in the switchover from one chemical to the next. Because of special equipment limitations, he cannot drain the beds; but rather must inject one chemical right after the other. His specifications are to throw away all B containing more than 10% by volume A and all A containing more than 10% B In other words if the bed contains A and he starts putting in B, he must start throwing away effluent when it is 10 % B and continue throwing it away until it is 90% B.

Our research group has found a theoretical method of predicting these results (see attached reference.) Before making a recommendation, we wish to confirm this theory for sand beds, using the laboratory sand column. Please check the theory involved by displacing a salt solution in water with plain water.

Attached reference: Perkins, T.K., and o.C. Johnson, “A Review of Diffusion and Dispersion in Porous Media,” SPE Journal, March, 1963, p. 70-83.


Gas Flow Bench-3

The initial work with previous laboratory group on a natural gas pipeline ignored that fact that at each pumping station there are 2 elbows that take the gas from the underground pipeline up to the compressor and an additional 2 elbows to take the gas from the compressor back to the underground pipeline. Your efforts in the laboratory are to develop a friction factor for the elbows so that they can be added to the friction factor for the length of the pipeline that is underground. As a result, your work in the laboratory should focus on the pressure drop that occurs for an elbow. With this experiment only information, you are to develop a friction factor versus Reynolds number correlation for various size elbows that are available on the gas flow bench. This correlation is to be compared with theory in your report. Once this correlation is available you are to determine the added power required of the pump to account for the extra elbows at each pumping station assuming that the distance between pumping stations is 55 km and that the pipeline diameter is the economic optimum diameter for a flow of 1 million SCFM in the pipeline.


Absorption Column-3

Operate the packed absorption column in the Chemical Engineering Laboratory to absorb C02 from a gas stream with water. Determine, for each of the packed columns, the number of transfer units and height of a transfer unit for C02 absorption. The group who operated the packed columns during the previous laboratory period was unable to close the material balances. The principal problem seemed to be obtaining reliable flow rate information for the air and water streams; it appears, therefore, that the air and water flow meters should be calibrated before you begin.

Be prepared in your oral quiz to derive the equations governing absorption in a packed column and present your experimental plan including how you propose to make a feed stream containing C02 and the concentrations you propose to employ. Discuss the measurements required, what analytical procedures you will use to determine C02 concentrations in the air and water streams, and how the data will be analyzed to determine the information requested.

Be prepared in your oral quiz to address the following:a) Safety issues with this experimentb) Equipment operationc) Data sheetsd) Other germane points with respect to this experiment


Fluidized Bed-3

Using the steel grit – SG 80 with the properties given on the ERVIN Industries web site (www.ervinindustries.com) with bulk density 3.44 gm/cc, tap density 3.99 gm/cc and steel density of 7.86 gm/cc determine the bed height with different superficial velocities ranging from 0 to 2.5 ft/s. This website gives information about the particle size distribution that is to be used in determining an average particle size for determination of fluidization characteristics using theory. Above the minimum fluidization velocity the bed will become a bubbling fluidized bed which will give difficulty in measuring the bed height such that determining the min and max height is a more realistic way of measuring the bed height than trying to determine the average bed height. In addition to the bed height, please determine the min/max pressure drop over the bed. Be sure to remove the pressure drop associated with the distributor plate so that only the pressure drop in the bed is given in your data. In your report please develop graphs of the min/max bed height and min/max pressure drop over the bed. Compare these graphs to those developed using theory associated with fluidized bed operation for this distribution of particle sizes.


http://www.ervinindustries.com/


For the double pipe heat exchanger in the laboratory you are to determine its dynamic behavior. To determine the dynamic behavior you are to determine the time constant assuming an exponential decay for both heat-up and for cool-down under flow conditions. This can be done by initially starting the flow of cold water into the shell side of the heat exchanger and establishing a steady-state temperature reading without any steam flowing into the unit. Then turn on the steam. Wait until a new steady state temperature is obtained. The exponential rise of temperature for the cold water flow can then be analyzed for a time constant, tc, which is the heat-up time constant. The cool-down time constant can be determined by starting at the end of the exponential rise of the cold water flow – this is steady state- and then shutting off the stream supplied to the system and watching the temperature of the cold water in the shell cool down to another steady-state. The best fit of the exponential cooling can again be characterized with a charactistic cool-down time. Using dynamic analysis, predict from first principles what the heat-up and cool-down times are for this apparatus and compare those predicted to those measured in your experiments.


Extruder-XHigh density polyethylene (HDPE) raw material is to be used to produce a continuous plastic fiber by extrusion through the fiber die which is attached to the Brabender single screw extruder in MEB 3520. In order to have any market value, the fiber that is produced by extrusion must have a smooth surface without any surface irregularities. In order to increase fiber stiffness or reduce fiber diameter, the take-up roller located near the extruder can be used to stretch the fiber after it exits the die but before it solidifies.

1. Carefully read the start-up procedure for the extruder that you will be given by the instructor. 2. By trial and error, use the process control program to find a temperature profile (for the four

temperature zones of the extruder) and an extruder screw speed that can be used to produce fiber of marketable quality at a stable, relatively low production rate. HDPE is usually extruded at temperatures between 140 and 150 0C. BE CAREFUL NOT TO OVERLOAD THE TORQUE ON THE SCREW AND BREAK THE SHEAR PIN OF THE EXTRUDER. Use the two rollers to wind up the fiber after it leaves the extruder. Be careful and follow safety precautions when you thread the fiber between the rollers! Use of gloves is required.

3. Measure the value of the polymer mass flow rate.4. Increase the degree of stretching of the extruder polymer fiber by systematically increasing

the rotational speed of the take-up rollers, keeping the screw speed fixed and keeping the temperature profile fixed. In the plastics industry, the “draw ratio” is used to quantify the degree of stretching of the extruded fiber. The draw ratio (DR) is defined as:

DR = average axial velocity of the polymer fiber where the film enters the rollers/average axial velocity of polymer at the exit of the extrusion die

For each rotational speed of the rollers, calculate DR using the polymer mass flow rate and the rotational speed of the rollers. Find the maximum possible value of DR at fixed value of polymer mass flow rate.

5. How does the diameter of the fiber depend on DR ? Is the observed dependence on DR consistent with predictions from fluid mechanics ?

6. Measure the bending stiffness of the extruded fiber as a function of DR using the Taber Stiffness Tester. The Taber tester is ordinarily used to measure the stiffness of paper via the standard procedure described by the American Society for Testing and Materials, ASTM D5342-95. Modify this standard procedure as appropriate for specimens that you cut from the extruded fiber. Use the measured stiffness to calculate the appropriate modulus of the extruded fiber.

7. Does the modulus determined from the Taber tester depend on DR? Why or why not?8. For fibers produced at large values of DR, determine whether or not the FTIR instrument can

be used to detect a difference in polymer chain alignment parallel and perpendicular to the direction of fiber stretching.


Double Pipe Heat Exchanger-X

Design an experiment to measure the inside film coefficient* for the double pipe heat exchanger as a function of the flow rate and other important parameters.

Determine the fractions of the resistance to heat transfer that can be attributed to the outside surface, the pipe wall, and the inside surface of the inner pipe. From your data, prepare estimates for these fractions and estimate, also, the extent to which the outside wall of the inner pipe is fouled.

In your report, present, in addition to the information asked above, suggestions, based on your experience in the project, for improving the heat transfer rate for this equipment.

*Hint: using Wilson plot of the data to determine inside film coefficient

Double Pipe Heat Exchanger-X

There have been several complaints about our double pipe heat exchanger concerning its heat transfer capacity. Evidently there is also some scale on the cold water side. Would you please run enough experiments to determine the scale heat transfer coefficient?

Please consult the article "Conquer Cooling-Water Fouling," by James G. Knudsen in the April, 1991 issue of Chemical Engineering Progress, pages 42-48.

Also, please answer the following questions:1. What is the scale heat transfer coefficient (if it exists)?2. Is it a function of the water velocity on the cold side? Show by graphical means and comments.3. What would happen to the overall heat transfer coefficient if we de-scaled the unit? Show by graphical or calculation means what improvement we would expect and the probable percentage increase.4. Are there any factors discussed in the suggested article that we can use? Give your recommendations and illustrate it quantitatively (by graphical means or other methods) if you can.

Shell and Tube Heat Exchanger-x

One of our customers would like to know the influence of conventional dimensionless groups employed for heat transfer analysis on the overall heat transfer coefficient of our shell and tube heat exchanger. Thus, you should run a series of tests varying the cold side rate while holding hot side constant and vice-a-versa. Develop an equation for the overall heat transfer coefficient as a function of these dimensionless groups (whatever they are).

Secondly, compare your results for this type heat exchanger with other results in similar exchangers found in the handbook or other literature.

Finally, as the unit has not been inspected internally for a long time, please determine the fouling factor for the unit.

Also, would I be able to tell the client what his heat transfer rate would be as a function of viscosity, density etc., from your correlations? If so, we would get a good sized job soon on a new chemical to replace the CFC's now used in refrigeration systems.

Spray Drier-XFor some coming work, we need to know the drying capacity of the pilot spray drier in our lab. Consider the following:

(a) In a paper a number of year ago (Gluckert, F. A., "A Theoretical Correlation of Spray Dryer Performance," AIChE Journal 8,460-466 (1962), the claim is made that the drying capacity of a spray drier can be calculated by means of a general correlation equation. You are to check this assertion by performing appropriate tests on the laboratory dryer.

(b) Operate the dryer with a distilled-water feed with inlet gas temperatures of 200 and 300°C and determine the maximum drying rate under these conditions.

(c) Operate the dryer with a solution feed of detergent soap at a normal concentration and the same inlet gas temperatures as under (a) above or select a better temperature if literature indicates differently. Select an appropriate solution concentration and determine the maximum drying rate under these conditions. Collect samples of the dried product for microscopic examination to determine the maximum diameter of the dried product. Also, determine the thermodynamic efficiency of the drier while drying sodium sulfate.

(d) If your results do not agree with the Gluckert correlation, your report must contain a quantitative explanation of the likely cause of the differences. This explanation must be supported by sample calculations.

(e) From your results recommend the size, number and operating conditions for spray drying 1000 pounds/hour of detergent soap for a customer.

Ebulliometer -X

You are to develop a comparison of the various methods available in the senior laboratory. The various analytical methods that are available are reviewed in the website:

http://www.winegrowers.info/wine_making/Alcohol.htm

One of these methods is the ebulliometer, others are potentially the gas chromatograph, densitometer, refractometer, hydrometers (used to be available in the lab), infra-red spectroscopy and liquid chromatography. For each of these techniques develop a calibration curve from self-prepared samples. Determine which of the calibration curves is indicative of the most accurate alcohol-water analysis.

The laboratory instructor will provide an unknown alcohol-water sample which is to be analyzed using the calibration curves developed for each of the analytical methods. Your final report is to report the results of the analysis of the unknown alcohol-water sample.


http://www.winegrowers.info/wine_making/Alcohol.htm

Ultrafiltration-X

The client from the Middle East has an aqueous solution of salt (100 gm/liter NaCl) and 0.1% wgt polyacrylic acid with pH in the range, 6< pH < 10. He would like to know if it can be separated by ultrafiltration to provide drinking water for the community. Using the laboratory ultrafiltration unit and membranes provided determine the conditions of pressure, flow rate and temperature that gives the largest flow of purified water. Be particularly aware that membrane fouling caused by increased solute concentration at the membrane surface either by macromolecular adsorption to the internal pore structure of the membrane or aggregation of the macromolecules deposited on the surface of the membrane causes concentration polarization which decreases permeate flux.

To start this project you will need to develop analytical methods to measure the concentration of polyacrylic acid and salt in water solution. You boss thinks that either UV-Vis or FTIR may be used for polyacrylic acid analysis and electrical conductivity may be used for NaCl analysis.

Use the best experimental conditions to design an ultrafiltration unit for this aqueous solution to process 1 million gallons per day for a community in the Middle East. Using the concentration polarization results determine the lifetime of the membrane for this application. Determine the cost for membrane replacement as well as the pumping costs over the course of 1 year’s operation giving a cost per million gallons of water produced.


CHEMICAL ENGINEERING 4903-2 - University of Utahring/ChE 4903 Projects lab/Laboratory... · Web viewCHEMICAL ENGINEERING 4903-2 FALL SEMESTER – 2013 SCHEDULE OF LABORATORY EXPERIMENTS

Documents

CHEMICAL ENGINEERING 4903-2 - University of Utahring/ChE 4903 Projects lab/Laboratory... · Web viewCHEMICAL ENGINEERING 4903-2 FALL SEMESTER – 2013 SCHEDULE OF LABORATORY EXPERIMENTS