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Homework assignments posted here are subject to correction in class or through other means.  Problems as assigned here are for your convenience but are not a substitute for obtaining assignments in class.  

Homework Assignment: 1 2 3 4 5 6 7 8 9 10 


Homework #1 (Due 8/25/08)

Ethics and the Engineering Profession

1. Watch the 30 minute video Ethics in Action: The Tradition of the Engineering Profession 2. Read the attached material on the Challenger Accident and the news articles regarding a relatively recent issue associated with a shuttle launch. In a well written essay, discuss the role the accident might have played in the decision making process on whether to launch Endeavour, or if you choose, in the Columbia disaster. You should also discuss how the Code of Ethics applies to the decision-making process made by NASA. Grading for your submission will be 75% on content and 25% on grammar/spelling/punctuation/style. You should consider the objectives for this assignment in composing your essay.

You should attempt to watch this movie as soon as possible to allow time to rectify any problems with distribution. You will only be able to watch this video from UK Engineering machines on campus.

2. Read the handout from Chemical Engineering Progress, "Engineering Ethics: What are the Right Choices?". Complete the survey on the last page and be prepared to discuss in class. You will submit this survey anonymously after the discussion. Participation in the discussion will be noted as part of your course grade.

Assignment Learning Objectives:

  • Explain the role the code of ethics plays in engineering decision-making
  • Explain the benefits of ethical practices in engineering
  • Apply the code of ethics to realistic scenarios in an appropriate manner
  • Justify the relationship between personal and professional ethics
  • Justify the need for a code professional ethics
  • Identify the characteristics of a profession

Reading Assignment:

  • Monday (8/25): Ch.2 35-59 Toxicology (HW1 Due, HW2 Assigned)
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Homework #2 (Due 9/08/08)

Toxicology

In-class problems:
1. 2-12
2. Find the OSHA PEL and ACGIH TVL for uranium oxide. Report the PEL, TVL, source, and URL (if applicable).

Problems for submission:
3.
2-27 (note that in Table 2-5, the causative variable for this scenario is the dose V in equation 2-5)
4. What is the concentration in mg/m3 of 7 ppm of carbon tetrachloride (aq)?
5. What is the concentration in mg/m3 of 25 ppm of ammonia (v)?

Assignment Learning Objectives:

  • Locate and interpret documentation expressing the toxicity of substances
  • Apply quantitative expressions for toxicity
  • Define relevant terms and acronyms

Reading Assignment:

  • Monday (9/8): Ch.3 63-103 Industrial Hygiene (HW2 Due, HW3 Assigned)
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Homework #3 (Due 9/15/08)

Industrial Hygiene

In-Class:
3-15

For Submission:
3-20

Assignment Learning Objectives:

  • Calculate TLV values for mixtures and determine if violations have occurred
  • Apply first law principles to determine required ventilation rates

Reading Assignment:

  • Monday (9/15): Ch.6 225-283 Fires and Explosions (HW3 Due, HW4 Assigned)
    View "Introduction to Reactive and Explosive Materials" (24 min.)
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Homework #4 (Due 9/22/08)

Fires and Explosions

In-Class Problems
6-8, 6-11, 6-12, 6-37

Problems for Submission:
6-1
6-3b
P1. Estimate the LFL and the UFL of Problem 6-3b at 100 oC.
P2. Estimate the UFL of Problem 6-3b at 10 atm of pressure.
6-9

Assignment Learning Objectives:

  • Perform flash point calculations for mixtures
  • Determine flammability limits for mixtures, including effects of temperature and pressure
  • Determine MOC of mixtures
  • Evaluate the effect of compression on ignition
  • Determine the required ignition energy of a system

Reading Assignment:

  • Monday (9/22): Ch. 10 429-460 Hazards Identification (HW4 Due, HW5 Assigned). View "Process Area Safety Features" (17 min.) And "Process Area Safety Procedures" (14 min.)
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Homework #5 (Due 9/29/08)

Hazards Identification

In-class Problems
10-9, 10-16, 10-17
P-1. Why should block valves that isolate pressure safety relief valves be inspected monthly to ensure they are sealed in an open position?

Problems for submission
10-8, 10-11, 10-22
P-2. An operating plant normally requires city water for a wide variety of uses. Some of these required uses at a plant include a drinking fountain, a safety shower, a chemical reactor, and an eyewash station. Should the chemical reactor overpressure, how could you ensure the integrity of the water supply to the drinking fountain, safety shower, eyewash station, and city water supply main? Draw a schematic diagram explaining your plan.

Assignment Learning Objectives:

  • Critically evaluate process situations and propose designs that minimize or eliminate hazards

Reading Assignment:

  • Monday (9/29): Ch. 11 471-499 Risk Assessment (HW5 Due, HW6 Assigned)
  • Monday (10/06): Midterm Exam
  • Monday (10/13): Ethics Discussion: Gilbane Gold (HW6 Due, HW 7 Assigned)
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Homework #6 (Due 10/13/08)

Risk Assessment

Problem for submission:
11-2

Assignment Learning Objectives:

  • Apply fault trees and event trees to risk assessments on process systems

Reading Assignment:

  • Monday (10/06): Midterm Exam
  • Monday (10/13): Ethics Discussion: Gilbane Gold (HW6 Due, HW 7 Assigned)
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Homework #7 (Due 10/20/08)

Safety Oriented Problem Solving: Thermodynamics Edition

Thermodynamics Principle: Vapor Liquid Equilibrium

Health and Safety Concept: Properties of Materials: Flash Point

Background: Most combustion reactions occur in the gas phase. In order for any flammable material to burn, there must be both fuel and oxidizer present. There must also be a minimum concentration of the flammable gas or vapor in the oxidizer. For most fires to occur, a minimum fuel concentration must exist in air at ambient temperature. The minimum concentration at which ignition will occur is called the lower flammability limit (LFL). If the flammable material is normally liquid, the liquid must e warm enough to provide a vapor-air mixture equal in fuel concentration to the LFL concentration. The liquid temperature at which the vapor concentration reaches the LFL can be found experimentally. It is usually measured using a standard method called a "closed cup flash point" test. The "flash point" of a liquid fuel is thus the liquid temperature at which the concentration of fuel vapor in air is large enough for a flame to flash across the surface of the fuel if an ignition source is present.
The flash point and the LFL concentration are closely related through the vapor pressure of the liquid. Thus, if the flash point is known, the LFL concentration can be estimated; and if the LFL concentration is known, the flash point can e estimated. In most cases, the calculation can be made for pure liquids using Raoult's law. However, if the liquid is a mixture, particularly one where the components are dissimilar, the liquid solution may be non-ideal. Then the liquid phase activity coefficients may need to be determined in an accurate estimate of the relationship between flash point and LFL is to be made. The system total pressure is ambient, so it is low enough for the vapor (or gas) phase above the liquid surface to be considered ideal.

Problem: Estimate the flash point of a mixture made by mixing 600 ml of methanol and 400 ml of water. The solution is not ideal, and the activity coefficients must be estimated. For the estimation of activity coefficients, first determine the activity coefficients for methanol-water solutions from vapor liquid equilibrium data. Assume that the activity coefficients are function of composition only, and do not depend on the system pressure and temperature. Is such an assumption justified? Vapor liquid equilibrium data can be found in Perry's Chemical Engineers' Handbook. Vapor pressure data can be found in the Handbook as well. The LFL of methanol can be found in NFPA 325M, Properties of Flammable Liquids or Sax's Dangerous Properties of Industrial Materials. Once the mixture is ignited, will it continue to burn?

Assignment Learning Objective:

  • Apply chemical engineering principles to safety oriented problems

Reading Assignment:

  • Monday (10/20) Ethics and Safety Discussion: Bhopal (reading material provided)
    View "Unraveling Bhopal" video
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Homework #8 (Due 10/27/08)

Safety Oriented Problem Solving: The Process Principles Edition

1. The liquid level in a tank 10 meters in height is determined by measuring the pressure at the bottom of the tank. The level gauge was calibrated to work with a liquid having a specific gravity of 0.9. If the usual liquid is replaced with a new liquid with a specific gravity of 0.8, will the tank be overfilled or underfilled? If the actual liquid level is 8 meters, what is the reading on the level gauge? Is it possible that the tank will overflow without the level gauge indicating the situation?

2. Large storage tanks are only capable of withstanding very low pressures or vacuums. Typically they are constructed to withstand no more than 20.3 cm of water gauge pressure and 6.3 cm of water gauge vacuum.  A particular tank is 10-m in diameter.

a) If an 80 kg person stands in the middle of the tank roof, what is the resulting pressure (in Pa) if the person's weight is distributed across the entire roof?

b) If the roof were flooded with 20.3 cm of water (equivalent to the maximum pressure), what is the total weight (in kg) of the water?

Assignment Learning Objectives:

  • Apply chemical engineering principles to safety oriented problems

Reading Assignments:

  • Monday (10/27): Personal Protective Equipment
    View "Personal Protective Equipment" video (HW8 Due)
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Homework #9 (Due 11/03/08)

Safety Oriented Problem Solving: The Fluid Mechanics Edition

Health and Safety Concept: Storing, Handling, and Transport

Background: There are many occasions when the thrust forces caused by high velocity, high rate flow will cause excessive forces on piping and associated equipment. Sometimes the design of relatively simple devices can be complicated by the possibility of severe mechanical loads on piping equipment. If proper precautions are not taken to prevent failure due to these forces, then very serious accidents can occur.

Some examples of such situations might be in the design of safety relive systems wherein there exists the possibility of suddenly initiated, very high velocity flow, with the consequent possibility of the discharge piping reacting with significant movement, as for example, after the manner of a garden hose that is not being held. Our experience tells us that the hose will move erratically about, discharging water in many directions. One should be aware that even heavy steel piping can behave similarly if it is not suitably constrained.

Another serious situation can develop from misuse of a rather common item that exits in laboratories, perhaps in laboratories where you have worked. This is the compressed gas cylinder. A typical situation might exist at your gas chromatograph, for example, where air is being used in conjunction with hydrogen, in the flame ionization detector. The air is usually supplied at a pressure in excess of 2000 lb/in2. If the cylinder is not properly restrained and held, it can be easily knocked over with possibly disastrous results if the valve is broken off in the fall.

The result of unexpectedly high thrust forces from flow may frequently be disastrous because of the rapid, violent, and unpredictable motion of a pipe, or as in the example above, a rather heavy gas cylinder. There is also the distinct possibility of equipment failure from the forces which would result in the discharge of dangerous materials to the air.

In this problem, you are asked to estimate some forces, the magnitude of which might easily cause equipment failure with the consequent loss of large quantities of a highly flammable material to the air. The result would almost certainly be a serious gas cloud explosion and fire.

Problem: A tank ship hauling Liquefied Natural Gas (LNG) is being unloaded into a 600,000 bbl storage tank at a rate of 55,000 gal/min through a 30-in. diameter, schedule 10 stainless steel pipe. The schematic diagram of the pipe inside the tank is shown on the next page. Determine the total upward force on the tank roof and the horizontal and vertical forces on the splash plate.

click to enlarge

Assignment Learning Objectives:

  • Apply chemical engineering principles to safety oriented problems

Reading Assignment:

  • Monday (11/03): Virtual Reality Simulations for Process Safety (HW9 Due)
    Oral Report update due 11/04 by 5PM
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Homework #10 (Due 11/10/08)

Safety Oriented Problem Solving: The Separations Edition

Mass Transfer Principles: Extraction
Health and Safety Concept: Hazardous Waste Generation and Disposal

Background: Most chemical manufacturing operations involve the generation, use, and disposal of substances that are hazardous because of their toxicity or flammability. In many cases, the hazardous substance is a chemical that is widely used and not considered dangerous. For example, common salt is used in many processes without causing any particular problems with toxicity. However, if salt is contained in water that is discharged to streams, it may cause irreversible damage to the environment, including both plant and animal life. Thus, while salt is not a particularly hazardous material to handle and to use in processing, it must be kept out of the water that is discharged from a plant. Other substances may be much more toxic, of course, and the must be kept from the environment as well.

The nature of the substances and their effects on the environment are sometimes known quite well, but sometimes it is only known that they have a toxic effect. Sometimes the toxic effects are inferred for one material through comparison with another similar material. For example, if we know that high concentrations of sodium chloride are toxic to certain plants in the ecosystem, we can infer that high concentrations of potassium chloride will also be toxic to the same plants. (Of course, we much keep in mind that the same substances my be required for life. Sodium and potassium salts are necessary for proper cell growth and reproduction; and potassium deficiencies in particular are encountered in nature. We frequent add potassium salts in the form of fertilizers to enhance plant growth.)

We cannot add large quantities of most substances to the ecosystem without damage. Thus, the kind and amount of materials present in water streams discharged from a plant must be closely monitored to make certain that the discharged water will be within the quality standards specified by the Environmental Protection Agency. The standards for the purity of discharged water depend on the substances in the water and the potential damage to the environment. Specific concentrations can be obtained from the Environmental Protection Agency.

The specific method used to remove hazardous substances from water depends on the nature of the hazardous substance and the concentrations involved. Several different methods can be used. The following problem illustrates one method that might be used.

Problem: The water used in a chemical processing plant contains a mixture of organic acids. The acids are not particularly toxic to the environment in small concentrations, but the concentration in the process water stream is 0.5% by weight leaving the process, and that concentration is too large for discharge. The acids cannot be used in the plant for any other purpose, and there is insufficient acid for their recovery, purification, and sale. The acids are soluble in hydrocarbons, and it is decided to extract the acids from the water streams by countercurrent liquid-liquid extraction, then use the hydrocarbon as a fuel for one of the plant process heaters. There is no chlorine, nitrogen, or sulfur in the acids, so when are burned with the fuel, They will not contribute any additional pollution to the air. The hydrocarbon used for the extraction is the fuel oil for the process heaters. Equilibrium data for the acid-water-oil system are given in the table below. Plot the data on a triangular diagram or use the McCabe Thiele approach and plot mass ratios of acid to solvent. Determine how much oil will be required to reduce the concentration of acid from the 0.5 mass percent in the feed to 0.05 mass percent, which has been found to be acceptable for discharge. The oil rate used in the process will be 1.5 times the minimum, and the water to be treated will enter the extraction system at a rate of 3500 gallons per day. The oil has a specific gravity of 0.88. Assume the process is to be performed in a countercurrent liquid-liquid extractor having an overall efficiency of 20%. How many stages will be required for the extractor?

Mass percent in water layer

Mass percent in oil layer

Acid

Water

Oil

Acid

Water

Oil

0.05

99.90

0.04

0.10

0.05

99.85

0.10

99.85

0.05

0.20

0.08

99.76

0.20

99.73

0.07

0.40

0.12

99.48

0.30

99.60

0.10

0.60

0.17

99.23

0.40

99.46

0.14

0.80

0.23

99.97

0.50

99.31

0.19

1.00

0.30

98.70

 

 

 

 

Assignment Learning Objectives:

  • Apply chemical engineering principles to safety oriented problems

Reading Assignment:

  • Monday (11/10): Homeland Security and the CPI (HW10 Due)
  • Monday (11/17): No meeting, AIChE Annual Meeting
  • Monday (11/24): Oral Presentations
  • Monday (12/01): Safety Scavenger Hunt
    Examine "Safety in Academic Chemistry Laboratories" (link on website)
    View "Laboratory Safety and Inspections" video
  • Monday (12/08): Final Exam (10:45 AM)
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