David Shonnard Department of Chemical Engineering

Module 1: Environmental Literacy: Environmental Issues, Risk, Exposure, and Regulations
David Shonnard Department of Chemical Engineering Michigan Technological University Introduction. This presentation will cover important concepts of risk and exposure as well as important regulations related to chemical engineering processes.

Module 1: Presentation Outline
Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Review of environmental impacts - Chapter 1 Environmental and health risk assessment - Ch. 2 Exposure calculations - Chapter 6 Environmental regulations of interest to chemical engineers - Chapter 3 Presentation Outline. None.

Module 1: Educational goals and topics
Students will: be introduced to major environmental issues related to chemical processing become familiar with the fundamentals of risk assessment be introduced to the major environmental regulations of interest to the chemical industry and the chemical engineer become aware of the major pathways and routes of exposure to industrial chemicals Educational Goals and Topics. In addition to becoming familiar with the fundamentals of risk assessment, the students will also become familiar with the basic applications associated with risk assessment.

Module 1: Potential uses of the module in chemical engineering courses
Design course: Introduce environmental literacy and regulations before assigning projects Freshman Engineering: Introduction to issues regarding environment / society / industry Potential Uses of the Module in Chemical Engineering Courses. None.

Module 1: Scope of environmental impacts (Ch 1)
Materials Materials Materials Materials Life- Cycle Stages Energy Energy Energy Energy Raw Materials Extraction Chemical Processing Product Manufacturing Use, Reuse, Disposal Pollution Control Pollution Control Wastes Wastes Wastes Wastes Scope of Environmental Impacts (Chapter 1). The first step in the life cycle chemical production process is “Raw Materials Extraction”. It is from here both wastes and a product are produced. The product goes on to “Chemical Processing” followed by “Product Manufacturing”. Materials and energy are required at each of these steps; wastes are also produced here. From “Product Manufacturing” the product goes to “Use, Potential Reuse, and Eventual Disposal”, again both materials and energy are required and wastes are produced. Each of the waste streams created through the “life cycle chemical production process” consists of midpoints or indicators. These indicators include global warming, ozone depletion, etc. These midpoints in turn lead to the potential harm to human health and the ecosystem. Green Engineering places an emphasis on pollution prevention or reduction of wastes instead of pollution control. Midpoints global warming ozone depletion smog formation acidification ecological harm Human health and ecosystem damage Endpoint

Module 1: U.S. Energy Flows, 1997
Annual Energy Review 1997, U.S. DOE, Energy Information Administration, Washington, DC, DOE/EIA-0384(97) U.S. Energy Flows, By looking at energy issues you can see the large impact they have on environmental impacts. This slide presents the U.S. Energy Flows from On the left hand side of the slide the energy inputs are presented, separated by the different fuels used. The middle of the slide shows the total energy supply (98.78 quadrillion Btu). The far right hand side of the slide shows the outputs and uses of energy separated by residential and commercial, industrial, and transportation. As demonstrated by the diagram, industry represents a significant portion of the total energy use. Based on knowledge of the industrial sector, there are opportunities for improvement as related to pollution associated with energy consumption.

Module 1: Global warming and related impacts
Materials Energy Cause and Effect Chain Products climate change; sea level change human mortality or life adjustments Chemical Processing greenhouse gas emissions CO2, CH4, N2O Global Warming and Related Impacts. During chemical processing, green house emissions are released. These are chemicals that when released cause global warming. To control these emissions, it is important to focus on chemical processes whose outputs include CO2, CH4, and N2O. These emissions may lead to climate change or sea level changes, which then in turn may lead to human mortality or life adjustments. The bottom pie chart demonstrates the importance of particular chemicals and the estimated contribution to global warming. The first of the two graphs represents the CO2 concentration over time. The early measurements were taken from ice core samples. The second graph gives a close up of measured CO2 concentration from the late 1970s through the early 1990s. The graph shows the leveling off of CO2 levels due to the phase out of specific chemicals and the Montreal Protocol. Contribution to global Warming; Phipps, NPPC, Climate Change 1995, Intergovernmental Panel on Climate Change, WMO and UNEP, Cambridge University Press, 1996.

Module 1: Stratospheric ozone and related impacts
Materials Energy Cause and Effect Chain Products ozone layer loss increase in uv Chemical Processing ozone depleting substances CFCs, HCFCs human mortality or life adjustments ecosystem damage Toxics Release Inventory Data Stratospheric Ozone and Related Impacts. This slide demonstrates the effects of CFCs and HCFCs on the environment. This is an issue that has received a great deal of press and that most students are aware of. A byproduct of chemical processing can include ozone-depleting substances (CFCs and HCFCs). There has been an increase in the release of HCFCs. The release of the compounds lead to ozone layer loss and an increase in ultra violet rays at the earth’s surface. This increase then may lead to human mortality or life adjustments as well as ecosystem damage. The first of the two charts at the bottom of the slide presents the trend in CFC-11 releases generated from Toxics Release Inventory (TRI) data. This shows that CFC-11 releases have decreased over this time period. The second chart presents the concentration of CFC-11 in the environment over time. This demonstrates that the concentration over time is leveling off.

Module 1: Smog formation and related impacts
Materials Energy Cause and Effect Chain Products photochemical oxidation reactions Chemical Processing human/ecological damage from O3 and other oxidants NOx and volatile organic substances 1 - Chemical & Allied Processing 2 - Petroleum & Related Industries NOx VOCs NOx 1997 Miscellaneous Smog Formation and Related Impacts. The importance of this slide is to introduce the main chemicals and processes associated with the generation of smog. From chemical processing, Nox and volatile organic substances are released; these byproducts are the main chemicals associated with smog production. These chemicals cause photochemical oxidation reactions to occur, generating low level ozone. This in turn can result in human and ecological damage from the ozone and other oxidants. The four graphs at the bottom of the slide present the amount of both NOx and VOCs that are emitted per year by major sources, and the breakdown of these releases on a percentage basis for Industrial processes. The first graph demonstrates that transportation and fuel combustion (NOx emissions are due to electrical utilities) are major contributors to NOx emissions. The second graph demonstrates that Transportation and Industrial processes represent major sources of VOC emissions. The pie charts show that chemical and allied processing represent over 1/3 of the total NOx emitted by industrial processes in 1997 and represent a much smaller portion of VOC releases. 3 - Metals Processing, 4 - Other Industrial Processes 5 - Solvent Utilization, 6 - Storage & Transportation 7 - Waste Disposal & Recycling Transportation Industrial Processes VOCs 1997 Fuel Combustion National Air Quality and Emissions Trends Report, 1997, U.S. EPA Office of Air Quality Planning and Standards,

Module 1: Acid rain / Acid deposition
Materials Energy Cause and Effect Chain Products Acidification rxns. & acid deposition Chemical Processing human/ecological damage from H+ and heavy metals SO2 and NOx emission to air SO2 1997 Miscellaneous 1 - Chemical & Allied Processing 2 - Petroleum & Related Industries 3 - Metals Processing 4 - Other Industrial Processes 5 - Solvent Utilization 6 - Storage & Transportation 7 - Waste Disposal & Recycling Acid Rain/Acid Deposition. In general students are familiar with this concept, chemical processing results in NOx and SO2 emissions to the air due to combustion processes. This in turn results in acidification reactions in the aqueous phase and acid depositon. The heavy metals are then released into recovery streams that may lead to human and ecological damage due to the H+ and the heavy metals. Fuel combustion is the primary source of the components that cause acid rain. In industrial processes most heating units use natural gas which has a low sulfur content, resulting in lower SO2 emissions. The pie chart demonstrates that for the industrial sector, the chemical and allied processing and petroleum and related industries accounted for nearly 50% of the SO2 emissions in 1997. Transportation Industrial Processes Fuel Combustion National Air Quality and Emissions Trends Report, 1997, U.S. EPA Office of Air Quality Planning and Standards,

Module 1: Human health toxicity
Materials Energy Products Chemical Processing Transport, fate, exposure pathways & routes Human health damage; carcinogenic & non... Toxic releases to air, water, and soil EPCRA Toxic Waste RCRA Hazardous Waste Human Health Toxicity. In some chemical processes the byproducts are toxic chemicals. These toxic chemicals are released to the air, water, and soil. The ultimate transport, fate, exposure pathways and routes may lead to human health damage, both carcinogenic and non-carcinogenic. RCRA- Resource Conservation and Recovery Act—tracks the generation, transportation, use, and ultimate disposal of hazardous waste. Chemical and Allied Products represent 51% of the RCRA hazardous waste generation. EPCRA- Emergency Planning and Community Right to Know Act—facilitates public knowledge of and access to information on the presence of toxic chemicals in communities, releases to the environment, and waste management activities involving toxic chemicals. Chemical and Allied Products represent 27% of the EPCRA hazardous waste generation. Allen and Rosselot, 1997

Module 1: Risk assessment: important questions (Ch 2)
What are the risks associated with a chemical, manufacturing process, or use of a product? How is risk quantified by professional risk assessors? Is risk assessment used by government agencies to regulate industry? (Yes!) Risk Assessment: Important Questions (Chapter 2). These are introductory questions that can be used to incorporate green engineering into the classroom. These are also questions the students may ask.

Module 1: Risk assessment: introductory concepts
Risk = F(exposure x hazard) Modules 1, Modules 1,2 Chapters 5, Chapters 2,5 Steps in risk assessment Hazard assessment Exposure assessment Dose/response relationships Risk characterization Risk Assessment: Introductory Concepts. This module presents a simple discussion of risk. Risk equals some function of exposure and hazard. In this slide the function is multiplicative; however, it may be a more complicated function of these two components. Chapters 2 and 5 present exposure calculations and chemical hazard information. The major steps in risk assessment include: .Hazard Assessment-Reviewing the potential hazard of chemicals .Exposure Assessment- Reviewing the pathways of exposure .Dose/Response Relationships-Reviewing the toxic response based on a specific dose (toxicology) Risk Characterization-Estimating the potential human harm

Module 1: Hazard assessment
Indicators of chemical toxicology Carcinogenic effects - Slope Factor (SF), Weight of Evidence (WOE) classification Noncarcinogenic effects - No Observable Adverse Effects Level (NOAEL), Reference Dose (RfD), Reference Concentration (RfC), Permissible Exposure Limit (PEL), Threshold Limit Value (TLV) Sources of Data for Health Effects 1. The Material Safety Data Sheet - MSDS 2. NIOSH Pocket Guide to Chemical Hazards ( 3. Integrated Risk Information System (IRIS) ( 4. National Library of Medicine (ToxNet) ( 5. Casarett and Doull’s “Toxicology, the Basic Science of Poisons”, Macmillan 6. Patty’s Industrial Hygiene and Toxicology, John Wiley & Sons Hazard Assessment. There are many factors that can be used to measure indicators of chemical toxicology. Carcinogenic effects are measured using Slope Factor (SF) -- Based on dose response studies on animals; or .Weight of Evidence (WOE) – Toxicological term in which classes of chemicals are ranked or “screened” based on characteristics of particular chemicals. Noncarcinogenic effects are measured based on toxic properties from animal studies. The list presented represents potential toxicity. Permissible Exposure Limits (PELs) and Threshold Limit Values (TLVs) are properties based on occupational exposure.

Module 1: Exposure assessment (Ch 6)
Occupational Exposure- exposure to people in the workplace Community Exposure- exposure outside the workplace Different modeling approaches and assumptions Exposure Assessment Methodology - Community Exposure 1. Identify all waste stream components and concentrations 2. Estimate release rates to the air, water, and soil 3. Choose proper exposure pathways (through environment) and routes (into humans) 4. Determine exposure concentrations at the point of exposure to humans using measurements or an environmental fate and transport model Exposure Assessment. There are two main ways to calculate exposure: Occupational and Community exposure. Chapter 6 presents a detailed discussion of occupational exposure. This slide focuses on the Exposure assessment methodology related to Community Exposure. Note: Environmental Fate Transport models should be used only in the absence of actual data.

Module 1: Exposure assessment - cont.
Multiple pathways are possible Exposure Routes 1. Inhalation 2. Ingestion 3. Dermal (skin) Exposure Assessment - Continued. This slide presents a chemical manufacturing process that has releases to the air and to the water through leaching, and the solubility characteristics of the released chemical. The concentration released is diluted or reacted with other compounds in the environment; however over time there would be a measurable concentration of the compounds in the environment.

Module 1: Exposure assessment - H2S release example
x = 300 m Atmospheric dispersion Model, Ca H = 0 m Q = kg/s H2S Rural release, daytime neutral atmosphere, x<500m, vx=4 m/s sysz = x1.78 Exposure Assessment – H2S release Example. This slide presents the difference in the concentration of H2S released in the daytime neutral atmosphere and nighttime stable atmosphere. It demonstrates that the maximum downwind concentration (Ca) is a function of atmospheric stability and the velocity of the wind. Rural releases are releases where the terrain is relatively flat, and there are no buildings that would interrupt the plume. There would be greater dispersion in an urban area. More details on Exposure Assessments are presented in Chapter 6. Rural release, nighttime stable atmosphere, x<500m , vx=2.5 m/s sysz = x1.66

Module 1: Dose/Response
How large a dose causes what kind of effect? Effective Dose (reversible) Toxic Dose (irreversible) Lethal Dose Dose/Response. The first figure presents a dose response curve based on an animal study. The typical units associated with animal testing are mg/kg body weight/day. The second graph presents the effective dose (the dose will illicit a toxic response but it is reversible), the toxic dose (the dose will illicit a toxic response and is NOT reversible), and the lethal dose (LD50 is the dose at which 50% of the dosed animals die. This is a common indicator for toxicity and can be used as a discriminator). Crowl and Louvar, Chemical Process Safety: Fundamentals with Applications, Prentice Hall, 1990

Module 1: Risk Characterization
Carcinogenic Risk Example (inhalation route) Exposure Dose (mg/kg/d) Result: # excess cancers per 106 cases in the population; 10-4 to 10-6 acceptable Dose - Response Relationship, Slope Factor (mg/kg/d)-1 Risk Characterization. The last step in risk assessment is to quantify the risk from exposure using the Dose-Response Relationship/Slope Factor for carcinogenic effects. The equation presented shows: Riski is a quantitative number that measures the number of excess cancers per 1x106 cases in the population. One cancer case in 1x106 is considered acceptable in some cases. The exposure dose can be either measured or estimated. The exposure frequency changes based on occupational or community exposure. The averaging time is based on a lifetime of exposure (70 years) Note: There all kinds of uncertainty related to risk characterization: .The Concentration is subject to uncertainty .The Dose-Response usually is subject to uncertainty because the information is extrapolated from high doses to low doses. It is necessary to recognize that the error bars may be very large when using this estimation method. Exposure Factors CR = contact rate (m3 air breathed / day) EF = exposure frequency (days / yr) ED = exposure duration (yr) BW = body weight (kg) AT = averaging time (days) - 25,550 days for carcinogenic risk

Module 1: Environmental regulations: the regulatory process (Ch 3)
Environmental Laws • Clean Air Act of 1970 Rule Making • publish proposed regulations in the Federal Register • receive public comment on proposed regulations • publish regulations in the Federal Register Administrative Agencies • US Environmental Protection Agency Environmental Regulations: The Regulatory Process. It is important to make the students aware of the Federal Regulations at a minimum, in many cases the States Regulations are more stringent than the Federal. Environmental Laws- These laws are passed by Congress; however, the implementation of these rules is not laid out in the law. For example, Congress passed the Clean Air Act but needs EPA and rule making efforts for it to be implemented into practice. The National Ambient Air Quality Standards (NAAQS) regulate the quality of air for the priority pollutants, including VOCs, lead, Particulate matter, and NOx Environmental Regulations • National Ambient Air Quality Standards (NAAQS)

Module 1: Environmental regulations: changes over time
Major Laws/Amendments Environmental Regulations Environmental Regulations: Changes over time. These figures present an explosion of environmental laws and regulations over time. Bishop, “Pollution Prevention: Fundamentals and Practice”, McGraw-Hill, 2000

The 9 essential environmental regulations: the manufacture of chemicals
The Nine Essential Environmental Regulations: The Manufacture of Chemicals. TSCA, FIFRA, and OSHA are environmental statues related to the manufacture of chemicals. More information on PMNs and TSCA is presented in Chapter 3. Note: Chemicals are not required to be tested. The decision on whether or not to test a chemical is part of EPA review. Approximately 5% of all PMNs require the company to perform actual testing. Of the 2000 chemicals that are submitted each year only 30% of them are actually produced.

The 9 essential environmental regulations : discharges to air, water, and soil
The Nine Essential Environmental Regulations: Discharges to Air, Water, and Soil. The CAA, CWA, and RCRA are environmental statues related to releases to air, water and soil.

The 9 essential environmental regulations : clean-up, disclosure, and pollution prevention
The Nine Essential Environmental Regulations: Clean-up, Disclosure, and Pollution Prevention. The CERCLA (a.k.a., Superfund), EPCRA, and PPA are environmental statues related to clean-up, disclosure, and pollution prevention.

Module 1: Recap Educational goals and topics covered in the module
Potential uses of the module in chemical engineering courses Review of environmental impacts - Chapter 1 Environmental and health risk assessment - Ch. 2 Exposure calculations - Chapter 6 Environmental regulations of interest to chemical engineers - Chapter 3 Recap. The potential uses of this module include incorporation into an existing design class or incorporating environmental literacy into a Freshman Engineering class.

Department of Chemical Engineering University of Texas at Austin
Module 2: Evaluating Environmental Partitioning and Fate: Approaches based on chemical structure - Chapter 5 David Allen Department of Chemical Engineering University of Texas at Austin Introduction. This module deals with evaluating environmental partitioning and fate using approaches based exclusively on chemical structure. Much of this information is presented in Chapter 5 of the text. After presenting this material the student should be able to do an environmental assessment of risk based solely on the structure of the compound. Dr. Allen recommends teaching on the issue of the day…use examples from the headlines.

Educational goals and topics covered in the module
Module 2: Evaluating Environmental Partitioning and Fate: Approaches based on chemical structure Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Overview of property estimation methods Software demonstration Case studies Evaluating Environmental Partitioning and Fate: Approaches Based on Chemical Structure. None.

Module 2: Educational goals and topics covered in the module
Students will: become aware of the chemical and physical properties that govern a chemical’s environmental partitioning and fate be able to estimate properties that govern environmental partitioning and fate based on chemical structure be able to perform mass balances to estimate environmental partitioning and be able to design structures that have targeted properties be aware of the limitations of structure-property estimation methods Educational Goals and Topics Covered in the Module. In addition to these objectives, the student will also understand the concept of structure activity, functional groups, and the multimedia fate of a chemical based on its structure.

Module 2: Educational goals and topics covered in the module (cont’d)
Properties covered: Properties used to estimate partitioning: boiling point, vapor pressure, octanol-water partition coefficient, bioconcentration factor, Henry’s law coefficient, soil sorption Properties that govern environmental fate: atmospheric lifetimes, biodegradation rates Typical values of properties Environmental partitioning calculations Educational Goals and Topics Covered in the Module (continued). None.

Design course: Use as a preliminary screen of chemical products and raw materials Materials course/thermodynamics course: Module on estimating properties Mass and energy balances course: module on estimating mass partitioning in closed systems Potential Uses of the Module in Chemical Engineering Courses. None

Module 2: Chemical properties for environmental decision-making
Chemical Properties for Environmental Decision-Making. None.

Module 2: Property estimation methods based on chemical structure
Empirical approach based on exp. Data Specific to chemical classes Termed structure-activity relationships (SARs) Approaches in Ch 5 Functional Groups (KOW, kOH, PBio) Bond Types (H) Molecular Connectivity (KOC) Linear Free Energy (kHyd) Property Estimation Methods Based on Chemical Structure. SARs are used to relate chemical structures to activity. The text presents the tools used by EPA for PMNs in Chapter 5. Note: Other approaches are valid, however, these are typical estimates. Functional groups, bond types, molecular connectivity, and linear free energy are all valid ways to group data to determine chemical properties.

Module 2: Property estimation methods based on other properties
Based on KOW, octanol-water partitioning BCF - bioconcentration factor LC50 - lethal dose 50% mortality S - water solubility of organic compounds KOC - organic carbon/water partitioning Property Estimation Methods Based on Other Properties. None.

Module 2: Functional groups
KOW - octanol-water partitioning Describes partitioning of organic pollutants between the water phase and octanol log Kow =  ni fi +  nj cj n = number of functional groups of types i or j fi = contribution to log Kow of group i cj = correction factor for functional group j Functional Groups. None.

Module 2: Functional groups 1,1-Dichloroethylene example
the molecular structure, CH2= CCl2 one =CH2 group one =CH- or =C< group two –Cl (olefinic attachment) groups log Kow = (0.4923) = 2.11 (no correction groups) Experimental log Kow = 2.13 Functional Groups 1,1-Dichloroethylene Example. “CH2”, “CH-“, “C<” and “-Cl” are all functional groups used to determine the chemical properties of 1,1-Dichloroethylene.

H - Henry’s law constant
Module 2: Bond Types H - Henry’s law constant Describes partitioning of organic pollutants between the water phase and air in the environment -log H =  ni hi +  nj cj n = number of bonds of types i or j hi = contribution to H of bond type i cj = functional group correction factor Bond Types. The basic premise behind bond types is that you count the number of similar bonds. It is very similar to functional groups.

Module 2: Bond Types 1-propanol example
the molecular structure, H H H    H – C – C – C – O - H 7 C-H bonds, 2 C-C bonds, 1 C-O bond, and 1 O-H bond -log H = 7( ) + 2(0.1163) = w correction; - log H = = linear or branched alcohols Experimental -log H = 3.55 Bond Types. None.

Module 2: Molecular connectivity
KOC - Organic carbon-water partition coeff. Describes partitioning of organic pollutants between the water phase and natural organic matter in soils/sediments log Koc = 0.531  njPj 1 = 1st order molecular connectivity index nj = number of groups of type j Pj = correction factor for group j Molecular Connectivity. This is used when there is not a simple structure relationship. The molecular connectivity index is a function of the topology of the molecule and the functional groups.

Module 2: Molecular connectivity 1-hexanol example
the molecular structure, CH3 – CH2 – CH2 – CH2 – CH2 – CH2 – O - H d (1) (2) (2) (2) (2) (2) (1) - atom connectivity (di,dj) (1,2) (2,2) (2,2) (2,2) (2,2) (2,1) bond connectivity 1 = (I* j)-0.5 1 = (1/2) + (1/4) + (1/4) + (1/4) + (1/4) + (1/2) = 3.41 log Koc = 0.531  njPj log Koc = 0.53 (3.41) (-1.519) = 0.91 Experimental log Koc = 1.01 Molecular Connectivity 1-hexanol Example. None. aliphatic alcohol

Module 2: Correction Factors
Chemical structure provides an incomplete description of molecular interactions leading to observable properties Correction Factors for intermolecular forces Electronic interactions Multiple hydrogen bonding Substituent effects Correction Factors. None.

Module 2: Software EPIWIN collection of software programs - Properties covered: Properties used to estimate partitioning: boiling point, vapor pressure, octanol-water partition coefficient, bioconcentration factor, Henry’s law coefficient, soil sorption Properties that govern environmental fate: atmospheric lifetimes, biodegradation rates Software. None.

Module 2, Case study 1: Environmental partitioning case study
Water Compartment Only 1 kg Hexachlorobenzene (Hx) 105 m3 volume of water 10-3kg organic carbon / m3 water 0.1 kg fish / 100 m3 water Human Exposure : Fish Ingestion 0.5 kg of fish consumed Dose due to ingestion? Concentration in the Fish (mg/kg)? Case Study 1: Environmental Partitioning Case Study. Use the data presented on this page and EPIWIN to answer the questions posed. Mackay et al., “Illustrated Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals”, Lewis Publishers, 1992

Module 2, Case study 1: Mass balance equation for Hx 118-74-1
Case Study 1: Mass Balance Equation for Hx The equation presented at the top of the slide is the mass balance equation: MHx = mass in humans, W= water, F = Fish, and S = Sediment. Open EPIWIN and enter the chemical’s CAS by clicking on “CAS Input”. This will then provide you with the properties used to assess environmental partitioning.

EPIWIN: Software demonstration
Concentration in Water 10-3 m3/L 105 m3 3,388 L/ kgOC 5,152 L/ kgF 10-3 kgOC/m3 10-1 kgF/ 102 m3 Concentration in Fish Software Demonstration. Use the data found using EPIWIN to calculate the concentration in the water and the fish and the ultimate dose to humans. Dose to Humans

Module 2, maleic anhydride 108-31-6 EPIWIN (estimates) vs ChemFate (data)
No data because MA hydrolyzes in 1 minute in water Maleic Anhydride EPIWIN (estimates) versus ChemFate (data). This table shows a clear example of where EPIWIN fails. This indicates that simple screening methods don’t always work, if possible a comparison of predicted to experimental data should be made. (See Attachment 1)

Module 2, Benzene 71-43-2 EPIWIN (estimates) vs ChemFate (data)
Benzene EPIWIN (estimates) versus ChemFate (data). This comparison indicates that EPIWIN does a good job at estimating environmental properties for this chemical. Note: These estimation tools were developed to estimate environmental properties not physical properties. DIPPR is a better source for physical properties. (See Attachment 2)

Module 2: Recap Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Overview of property estimation methods Software demonstration Case studies Recap. The main questions for the students at the conclusion of this module should be: .What are the environmental properties? .How can you estimate these properties? .What are some estimation tools? .How well do the estimation methods work? .What types of calculations are used? .How well do they perform? The main focus of Chapter 5 is: .How do I assess Environmental performance? .How can I design a better system? See Attachment 3 for information Green Chemistry Expert System

Module 3: Evaluation of Alternative Reaction Pathways Chapters 7 and 8
David T. Allen Department of Chemical Engineering University of Texas at Austin Introduction. This module evaluates reaction pathways beyond the molecular level and introduces them on a process level. The green engineering text breaks this down into three tiers. Tier 1 – Basic input/output information is known: Raw materials and products Tier 2 – Basic Block Diagram: pressure, temperature not necessary to complete Tier 3 – Detailed Flow diagram: Pressure, temperature, and flow rates are presented From this module students should be able to assess environmental performance and improve engineering design.

Module 3: Outline Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Green chemistry concepts - atom efficiency Tier 1 environmental impact assessment Green chemistry expert system (software) Adipic acid and maleic anhydride cases Outline. None.

Students will: understand the hierarchical design-for-environment approach for chemical processes learn qualitative and quantitative methodologies for Green Chemistry be able to evaluate feedstocks, solvents, and alternative reaction pathways; both economically and environmentally. Education Goals and Topics Covered in the Module. In addition, students should be thinking about environmental issues at each stage of the design process.

Design course: Green Chemistry concepts and a screening of chemical products and raw materials on the basis of economics and environmental impacts Reactor design course: Waste and risk minimization approaches Potential Uses of the Module in Chemical Engineering Courses. None.

Module 3: Hierarchical design process for pollution prevention
Hierarchical Design process for Pollution Prevention. This slide presents Tier 1 through Tier 3 in more detail

Module 3: Green Chemistry - Ch 7
Guiding principles for reactions Simplicity Safety High yield and selectivity High energy and atom efficiency Use of renewable resources Recyclable reagents and raw materials Green Chemistry -- Chapter 7. None.

Module 3: Feedstocks and solvents
Important considerations Human / ecosystem health properties Bioaccumulative? Persistent? Toxic? Global warming, Ozone depletion, Smog formation? Flammable or otherwise hazardous? Renewable or non renewable resource? Life cycle environmental burdens? - Ch 13, 14 Feedstocks and Solvents. Life cycle environmental burdens are a concept that as engineers we need to think about including the ultimate use and disposal of products.

Module 3: Alternative choices: raw materials
Benzene • fossil fuel source • carcinogenic Glucose • renewable source • non-toxic Alternative Choices: Raw Materials. Look back to Page 6 of this module. Go through the examples of Green chemistry. Note for this example the different routes used to produce adipic acid and the solvent changes.

Module 3: Alternative choices: Solvents
Supercritical CO2 Non-toxic, non-flammable, renewable sources Selectivity enhancement with SC CO2 Water as alternative solvent (as a co-solvent with an alcohol) Alternative Choices: Solvents. None. Reaction rate enhancements

Module 3: Synthesis pathways
Synthesis Pathways. Note: Different types of chemicals create different products and byproducts.

Module 3: Atom and Mass Efficiency: magnitude of improvements possible
Atom Efficiency - the fraction of starting material incorporated into the desired product - C6H5-OH+ NH3  C6H5-NH2 + H2O • Carbon - 100% • Hydrogen - 7/9 x 100 = 77.8% • Oxygen - 0/1 x 100 = 0% • Nitrogen - 100% Mass Efficiency (Basis 1 mole of product) C6H5-OH+ NH3  C6H5-NH2 + H2O Mass in Product = (6 C) (12) + (7 H) x (1) + (0 O) x 16) + (1 N) x (14) = 93 grams Mass in Reactants = (6 C) (12) + (9 H) x (1) + (1 O) x 16) + (1 N) x (14) = 111 grams Mass Efficiency = 93/111 x 100 = 83.8% Atom and Mass Efficiency: Magnitude of Improvements Possible. Atom efficiency is a concept you see frequently in green chemistry, it is one way to look at efficiency but it is not the only way.

Module 3: Software exploration Green Chemistry Expert System
TOPIC AREAS • Green Synthetic Reactions search a database for alternatives • Designing Safer Chemicals information on chemical classes • Green Solvents/Reaction Conditions alternative solvents / uses - solvent properties Software Exploration: Green Chemistry Expert System. Note: At this point chemical engineering students may feel frustrated and be asking themselves how will they develop these alternatives. At this point it is a good idea to discuss green chemistry.

Module 3: Software demonstration Green Chemistry Expert System
Software Demonstration Green Chemistry Expert System. This system can be used when a chemist develops a new chemical and as a chemical engineer, you have to assess the chemical. See Attachment 1. search Green Synthetic Reactions for adipic acid references

Module 3: Adipic Acid Synthesis Traditional vs. New
Traditional Route - from cyclohexanol/cyclohexanone Cu (.1-.5%) C6H12O+ 2 HNO H2O C6H10O4 + (NO, NO2, N2O, N2) V (.02-.1%) 92-96% Yield of Adipic Acid • Carbon - 100% • Oxygen - 4/9 x 100 = 44.4% • Hydrogen - 10/18 x 100 = 55.6% • Nitrogen - 0% Product Mass = (6 C)(12) + (10 H)(1) + (4 O)(16) = 146 g Reactant Mass = (6 C)(12) + (18 H)(1) + (9 O)(16) + (2 N)(14) = 262 g Mass Efficiency = 146/262 x 100 = 55.7% hazardous global warming ozone depletion Adipic Acid Synthesis Traditional vs. New. None. Davis and Kemp, 1991, Adipic Acid, in Kirk-Othmer Encyclopedia of Chemical Technology, V. 1,

Module 3: Adipic Acid Synthesis Traditional vs. New
New Route - from cyclohexene Na2WO4•2H2O (1%) C6H H2O C6H10O4 + 4 H2O [CH3(n-C8H17) 3N]HSO4 (1%) 90% Yield of Adipic Acid • Carbon - 100% • Oxygen - 4/8 x 100 = 50% • Hydrogen - 10/18 x 100 = 55.6% Product Mass = (6 C)(12) + (10 H)(1) + (4 O)(16) = 146 g Reactant Mass = (6 C)(12) + (18 H)(1) + (8 O)(16) = 218 g Mass Efficiency = 146/218 x 100 = 67% Adipic Acid Synthesis Traditional vs. New. None. Sato, et al. 1998, A “green” route to adipic acid:…, Science, V. 281, 11 Sept

Module 3: Maleic Anhydride Synthesis Benzene vs Butane - Mass Efficiency
Benzene Route (Hedley et al. 1975, reference in ch. 8) V2O5 2 C6H6 + 9 O2 2 C4H2O3 + H2O + 4 CO2 (air) MoO3 95% Yield of Maleic Anhydride from Benzene in Fixed Bed Reactor Butane Route (VO)2P2O5 C4H O2 C4H2O0 + 4 H2O (air) 60% Yield of Maleic Anhydride from Butane in Fixed Bed Reactor Maleic Anhydride Synthesis Benzene vs. Butane – Mass Efficiency. Mass Efficiency is a green chemistry concept; you can also calculate atomic efficiency. There is no single “correct” measurement of efficiency. Felthouse et al., 1991, “Maleic Anhydride, ..”, in Kirk-Othmer Encyclopedia of Chemical Technology, V. 15,

Module 3: Maleic Anhydride Synthesis Benzene vs Butane - Summary Table
Maleic Anhydride Synthesis Benzene vs. Butane – Summary Table. Think of the reaction pathways based on persistence, bioaccumulation, and toxicity (PBT). At this point the students have the group data necessary to calculate persistence and bioaccumulation, recommend providing data sources for toxicity. 1 Rudd et al. 1981, “Petroleum Technology Assessment”, Wiley Interscience, New York 2 Chemical Marketing Reporter (Benzene and MA 6/12/00); Texas Liquid (Butane 6/22/00) 3 Threshold Limit Value, ACGIH - Amer. Conf. of Gov. Indust. Hyg., Inc. , 4 Toxicity Weight, and 5 ChemFate Database - EFDB menu item

Module 3: Maleic Anhydride Synthesis Benzene vs Butane - Tier 1 Assessment
Benzene Route Butane Route Maleic Anhydride Synthesis Benzene vs. Butane -- Tier 1 Assessment. None.

Module 3: Recap Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Green chemistry concepts Tier 1 environmental impact assessment Green chemistry expert system (software) Adipic acid and maleic anhydride cases Recap. In addition it is important to note the first step is a qualitative assessment then the use of expert systems.

Module 3: Explore Green Chemistry Expert System
search Green Solvents/Reaction Conditions Designing Safer Chemicals

Department of Chemical Engineering Michigan Technological University
Module 4: Environmental Evaluation and Improvement During Process Synthesis - Chapters 8 and 9 David R. Shonnard Department of Chemical Engineering Michigan Technological University Introduction. Module 4 discusses unit operations and the associated control technologies. Module 5 was excluded from the presentation.

Module 4: Outline Educational goals and topics covered in the module
After the Input-Output structure is established, an environmental evaluation during process synthesis can identify large sources of waste generation and release; directing the attention of the designer to pollution prevention options within the process Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Identify and estimate emissions from process units - Chapter 8 Pollution prevention strategies for process units - Chapter 9 Outline. Pollution prevention strategies for process units includes a reduction of the overall releases as well as a decrease in the toxicity of the releases.

Students will: estimate air emissions and other releases from process units after developing a preliminary process flowsheet, using software and hand calculations have a better understanding of the mechanisms for pollutant generation and release from process units become familiar with practical pollution prevention strategies for process units Education Goals and Topics Covered in the Module. None.

Mass/energy balance course: • criteria pollutant emissions from energy consumption • emission of global change gases from energy consumption • calculate emission factors from combustion stoichiometry Continuous/stagewise separations course: • evaluate environmental aspects of mass separating agents Design course: • pollution prevention strategies for unit operations Reactor design course: • environmental aspects of chemical reactions and reactors • pollution prevention strategies for chemical reactors Potential Uses of the Module in Chemical Engineering Courses. None.

Chapter 8 Identifying and estimating air emissions and other releases from process units 1. Identify waste release sources in process flowsheets 2. Methods for estimating emissions from chemical processes 3. Case study - Benzene to Maleic Anhydride process evaluation Chapter 8. The case study involving benzene and maleic anhydride process evaluation includes developing an emissions inventory.

Module 4: Typical waste emission sources from chemical processes - Ch 8
1. Waste streams from process units 2. Major equipment - vents on reactors, column separators, storage tanks, vacuum systems, .. 3. Fugitive sources - large number of small releases from pumps, valves, fittings, flanges, open pipes, .. 4. Loading/unloading operations 5. Vessel clean out, residuals in drums and tanks 6. Secondary sources - emissions from wastewater treatment, other waste treatment operations, on-site land applications of waste, .. 7. Spent catalyst residues, column residues and tars, sludges from tanks, columns, and wastewater treatment, … 8. Energy consumption - criteria air pollutants, traces of hazardous air pollutants, global warming gases, Typical Waste Emission Sources from Chemical Processes- Chapter 8. Waste streams include wastewater, air emissions, and related solids. Fugitive sources are estimated based on a large number of small releases; however, the entire emission inventory may be very high based solely on the these emissions. Also because this is a calculated aggregate, any one of the sources used to calculate the emissions may be emitting at less than or more than the predetermined amount; however in the aggregate the calculations are valid.

Module 4: Process release estimation methods
1. Actual measurements of process waste stream contents and flow rates or indirectly estimated based on mass balance and stoichiometry. (most preferred but not always available at design stage) 2. Release data for a surrogate chemical or process or emission factors based on measured data 3. Mathematical models of emissions (emission correlations, mass transfer theory, process design software, etc.) 4. Estimates based on best engineering judgement or rules of thumb Process Release Estimation Methods. 1. New design processes and flow sheets will not have actual data measurements associated with them Release data and emission factor data can be found in AP-42, Air Chief. 3. Mathematical models are used to predict air emissions, for example ASPEN can readily predict emissions from absorbers. 4. Engineering judgement was used extensively in the 70s and 80s when there was not a lot of measured data to determine estimates.

Module 4: Emission estimation methods: based on surrogate processes
Waste stream summaries based on past experience 1. Hedley, W.H. et al. 1975, “Potential Pollutants from Petrochemical Processes”, Technomics, Westport, CT 2. AP-42 Document, Chapters 5 and 6 on petroleum and chemical industries, Air CHIEF CD, 3. Other sources i. Kirk-Othmer Encyclopedia of Chemical Technology, 1991- ii. Hydrocarbon Processing, “Petrochemical Processes ‘99”, March 1999. Emission Estimation Methods: Based on Surrogate Processes. None.

Module 4: Emission Factors - major equipment
Emission Factors- Major Equipment. These emission factors are based on through-put. The emission factors presented in Table are from the US EPA Locating and Estimating Database. Each of these emission factors were given a data quality qualifier ranging from A-E to represent the quality of the data.

Module 4: Emission factors - fugitive sources; minor equipment
Emission Factors - Fugitive Sources; Minor Equipment. A major source of emissions at industrial facilities are from fugitive sources. The Equation at the bottom represents the emissions (Ei); where mi = the mass fraction EFav = the average Emission factor Ns = The number of sites 24 = Hours of release per day 365 = Days per year

Module 4: Emission factors - criteria pollutants from energy consumption
Emission Factors - Criteria Pollutants from Energy Consumption. In the first column the emission factor related to SO2 is presented as a number, X, multiplied by S, the percent sulfur in the fuel oil. The equation presents the emissions released, Ei, in pounds per year where: EFav = Average emission factor ED = Energy Duty or the energy used per year HV = Heating value of the fuel BE = Boiler Efficiency An engineer can compare one process, or tank, or fuel to another to pick the best overall design. AP-42, Chapter 1, section 1.3, Air CHIEF CD,

Module 4: Emission factors - CO2 from energy consumption
Emission Factors - CO2 from Energy Consumption. None. AP-42, Chapter 1, section 1.3, Air CHIEF CD,

Module 4: Emission correlations/models - storage tanks and waste treatment
Software Tools Storage tanks TANKS program from EPA - Wastewater treatment WATER8 - on Air CHIEF CD - Treatment storage and disposal facility (TSDF) processes CHEMDAT8 - on Air CHIEF CD Emission Correlations/Models - Storage Tanks and Waste Treatment. TANKS 4.0 shows how emissions change based on different tank shapes and types.

Module 4: Benzene to MA Process
V2O5 2 C6H6 + 9 O > 2 C4H2O3 + H2O + 4 CO2 MoO3 Benzene to MA Process. This slide presents the process diagram and balanced equation related to using benzene to produce Maleic Anhydride. AP-42, Chapter 6, section 6.14, Air CHIEF CD,

Module 4: Air emission and releases sources: Benzene to MA Process
Source Identification 1. Product recovery absorber vent 2. Vacuum system vent 3. Storage and handling emissions 4. Secondary emissions from water out, spent catalyst, fractionation column residues 5. Fugitive sources (pumps, valves, fittings, ..) 6. Energy consumption Air Emission and Releases Sources: Benzene to MA Process. This slide summarizes the sources of emissions related to this process.

AirCHIEF Demonstration
Module 4: emissions from energy consumption: Criteria pollutants (SO2, SO3, NOx, CO, PM) Process data for energy consumption • 0.15 lb fuel oil equivalent per lb Maleic Anhydride product • fuel oil #6 in a Normally Fired Utility Boiler • 1% sulfur • Boiler efficiency included in the energy usage data AirCHIEF Demonstration Emissions from Energy Consumption: Criteria Pollutants (SO2, SO3, NOX, CO). For the AirCHIEF demonstration go to Click on AP-42, Click on Chapter 1, Click on the PDF ICON for Section Click on tables and figures once the PDF file has downloaded onto your computer. Click on table This table is the same as the table presented on the previous slide. Using the factors presented here, the emissions can be calculated.

Module 4: emissions from energy consumption: continued
Emissions from Energy Consumption: Continued. The emission factors and energy duty are combined in these equations to calculate the emissions related to 1000 pounds of MA.

Module 4: Uncontrolled Air emission / releases Benzene to MA Process (lb/103 lb MA)
Uncontrolled Air Emission/Releases Benzene to MA Process (lb/1000 lb MA). The 5.5 lbs circled under Criteria Pollutants represents the Energy use emissions calculated on the previous slide using the AirCHIEF CD.

Module 4: Flowsheet evaluation - n-butane to maleic anhydride
Flowsheet Evaluation - n-Butane to Maleic Anhydride. This slide presents the schematic flow diagram related to the use of n-butane to produce maleic anhydride as opposed to using benzene. The first reactor is where the maleic anhydride is processed. In the first absorber the non condensables include unreacted butane, CO, and CO2, and are released as off-gases. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 15, pp

Module 4: Uncontrolled Air emission / releases n-butane to MA Process (lb/103 lb MA)
Uncontrolled Air Emission/Releases n-Butane to MA Process (lb/1000 lb MA). None.

Module 4: Tier 2 environmental assessment indexes
1. Energy: [total energy (Btu/yr)] / [production rate (MM lb/yr)] 2. Materials: [raw materials (MM lb/yr)] / [production rate (MM lb/yr)] 3. Water: [process water (MM lb/yr)] / [production rate (MM lb/yr)] 4. Emissions: [total emissions and wastes (MM lb/yr)] / [production rate (MM lb/yr)] 5. Targeted emissions: [total targeted emissions and wastes (MM lb/yr)] / [production rate (MM lb/yr)] Tier 2 Environmental Assessment Indices. None.

Module 4: Benzene to MA Process Conclusions from emissions summary
1. Chemical profile: CO2 > CO > benzene > tars-oxygenates > MA 2. Toxicity profile: Benzene > MA > CO > tars-oxygenates > CO2 3. Unit operations profile: Absorber vent > energy consumption > vacuum system vent - Pollution prevention and control opportunities are centered on benzene, the absorber unit, and energy consumption - Benzene to MA Process Conclusions from Emissions Summary. None.

Pollution prevention strategies for process units
Module 4: Chapter 9 Pollution prevention strategies for process units 1. Material choices for unit operations 2. Pollution prevention for chemical reactions and reactors 3. Separation units: reducing energy consumption and wastes 4. Preventing pollution for storage tanks and fugitive sources 5. Case study applications - • VOC recovery/recycle: effect of MSA choice on energy consumption • Maleic anhydride from n-butane: MA yield vs reaction temperature Chapter Incorporating pollution prevention by reducing consumption and wastes 5. MSA - Mass separating agent

Module 4: Important issues regarding pollution prevention for unit operations
1. Material selection: fuel type, mass separating agents (MSAs), air, water, diluents, heat transfer fluids 2. Operating conditions: temperature, pressure, mixing intensity 3. Energy consumption: high efficiency boilers, operation of units to minimize energy usage 4. Material storage and fugitive sources: storage tank choices and equipment monitoring and maintenance 5. Waste generation mechanisms: understanding this will lead to pollution prevention strategies Important Issues Regarding Pollution Prevention for Unit Operations. None.

Module 4: Pollution prevention through material selection - fuel type
Example Problem: Calculate the annual uncontrolled SO2 emissions to satisfy a steam energy demand of 108 Btu/yr with a boiler efficiency of .85 assuming Fuel Oil #6, #2, and Natural Gas. Pollution Prevention through Material Selection - Fuel Type. In this example problem it is obvious that the selection of the fuel type has a large effect on the releases. By looking at the Emission factors and the sulfur content for each fuel type one can see that the #6 Fuel oil has the highest emissions and the natural gas has the lowest. This is why most process heating units use natural gas today.

Module 4: Pollution prevention through material selection - water pretreatment
Reverse Osmosis Pollution Prevention through Material Selection - Water Pretreatment. This slide represents crude oil processing. The process water from wells and the crude oil enter the desalting unit. In this unit the crude oil is contacted with water to remove any salts, precipitates and solids. If the process water is pretreated using reverse osmosis the amount of solids will be decreased and therefore the amount of RCRA waste generated will be reduced. to prevent 10 kg sludge/kg ppt RCRA waste

Module 4: Pollution prevention through material selection - reactor applications
1. Catalysts: • that allow the use of more environmentally benign raw materials • that convert wastes to usable products and feedstocks • products more environmentally friendly - e.g. RFG / low S diesel fuel 2. Oxidants: in partial oxidation reactions • replace air with pure O2 or enriched air to reduce NOx emissions 3. Solvents and diluents : • replace toxic solvents with benign alternatives for polymer synthesis • replace air with CO2 as heat sinks in exothermic gas phase reactions Pollution Prevention through Material Selection- Reactor Applications. None.

Module 4: Pollution prevention for chemical reactors
1. Reaction type: • series versus parallel pathways • irreversible versus reversible • competitive-consecutive reaction pathway 2. Reactor type: • issues of residence time, mixing, heat transfer 3. Reaction conditions: • effects of temperature on product selectivity • effect of mixing on yield and selectivity Pollution Prevention for Chemical Reactors. None.

Module 4: Pollution prevention for chemical reactions
1st Order Irreversible Parallel Reactions High Conversion t > 5(kp+ kw)-1 High Selectivity kp >> kw Selectivity Independent of residence time Pollution Prevention for Chemical Reactions. A high conversion time is associated with a long residence time. This graph shows the effect of the ratio of forward Kp versus Kw on yield selectivity. Note that for a first order irreversible parallel reaction, the selectivity is independent of the residence time.

1st Order Irreversible Series Reactions High Conversion t > 5 kp-1 High Selectivity kp >> kw Selectivity dependent on residence time Pollution Prevention for Chemical Reactions. For first order irreversible series reactions the selectivity is dependent on residence time. This is different than parallel reactions as shown on slide 29.

Reversible Series Reactions CH4 + H2O  CO + 3H2 Steam reforming of CH4 CO + H2O  CO2 + H2 R = CH4 P = CO W = CO2 Pollution Prevention for Chemical Reactions. This slide presents an example reversible series reaction. This also includes a recycle of unreacted feed and by product CO2 to reduce the waste to zero. Separate and recycle waste to extinction

Module 4: Pollution prevention - reactor types
1. CSTR: • not always the best choice if residence time is critical 2. Plug flow reactor: • better control over residence time • temperature control may be a problem for highly exothermic reactions 3. Fluidized bed reactor : • if selectivity is affected by temperature, tighter control possible 4. Separative reactors: • remove product before byproduct formation can occur: series reactions Pollution Prevention -Reactor Types. 4. Separative reactors are discussed in more detail in chapter 9 of the Green Engineering Textbook.

Module 4: Pollution prevention - reaction temperature
1st Order Irreversible Parallel Reactions For Ep > Ew, Ep was set to 20 kcal/mole and Ew to 10 kcal/mole. for Ep > Ew, Ep = 20 kcal/mole Ew to 10 kcal/mole for Ew > Ep, Ep = 10 kcal/mole Ew to 20 kcal/mole E = activation energy Pollution Prevention - Reaction Temperature. This slide shows the effect of temperature on the rate constant K.

Module 4: Pollution prevention - mixing effects
CSTR Bo Ao Irreversible 2nd order competitive-consecutive reactions Y = yield = P/Ao Yexp = expected yield t = mixing time scale Increased mixing will increase observed yield Pollution Prevention- Mixing Effects. This slide presents the effects mixing has on yield in a CSTR. The figure in the top right of the slide shows that Bo is a reactant that is metered into a CSTR whereas Ao is charged. As the graph indicates increased mixing will increase the observed yield (i.e., the actual yield will become closer and closer to the expected or theoretical yield).

Module 4: Pollution prevention - other reactor modifications
1. Improve Reactant Addition: • premix reactants and catalysts prior to reactor addition • add low density materials at reactor bottom to ensure effective mixing 2. Catalysts: • use a heterogeneous catalyst to avoid heavy metal waste streams • select catalysts with higher selectivity and physical characteristics (size, porosity, shape, etc.) 3. Distribute flow in fixed-bed reactors 4. Heating/Cooling: • use co-current coolant flow for better temperature control • use inert diluents (CO2) to control temperature in gas phase reactions 5. Improve reactor monitoring and control Pollution Prevention - Other Reactor Modifications. None.

Module 4: Pollution prevention - for separation devices
1. Choose the best technology: • take advantage of key property differences (e.g. volatility for distillation) 2. Choose the best mass separating agent: • consider operability, environmental impacts, energy usage, and safety 3. Separation Heuristics • combine similar streams to minimize the number of separation units • separate highest-volume components first • remove corrosive and unstable materials early • do the most difficult separations last • do high-purity recovery fraction separations last • avoid adding new components to the separation sequence • avoid extreme operating conditions (temperature, pressure) Pollution Prevention - for Separation Devices. Also note that although temperature can increase yield it can also have negative effects at extreme operating conditions. For example, a high temperature in a regenerator can cause the formation of tar.

Module 4: Pollution prevention - example of mass separating agent choice
HYSYS Flowsheet Absorber oil recycle Absorber Vent; 90% recovery of VOC MSA Screening chemicals 2. Hansen Sol. Par. 11.8  dd  22 0  dp  9.3 0  dh  11.2 3. Tbp > 220 ˚C 4. Tmp < 26 ˚C 5. 23 chemicals remain Pollution Prevention - Example of Mass Separating Agent Choice. The flowsheet presented in the center of the slide is essentially a closed system. For this example , a graduate student looked at 857 chemicals using Hansen Sol Par that could be used as mass separating agents in this system. The student then screened chemicals based on the properties shown in the box to the right (bullets 2 -4). After the screening process, 23 chemicals remained to simulate and to determine the best MSA to use for this system. After completing the simulations, the graduate student found that there was over a factor of 4 in difference in energy used based on the different absorber oils used. This study showed that the choice of mass separating agent can effect energy consumption. Conditions for simulations 1. 10-stage columns, 2. 10 ˚C approach temperature for heat integration, 3. absorber temperature = 32 ˚C

Module 4: Pollution prevention - results of mass separating agent choice
Pollution Prevention - Results of Mass Separating Agent Choice. This table presents the utility (Btu/hr) and rank for the 23 chemicals simulated. A limit of the HYSY is that it doesn’t include evaporation or any emerging technologies.

Module 4: Pollution prevention - Storage Tanks
Emission Mechanisms; Fixed Roof Tank LTOTAL = LSTANDING + LWORKING Vent Vapor pressure of liquid drives emissions DT DP Liquid Level - Weather, paint color/quality - Weather - liquid throughput, volume of tank Pollution Prevention - Storage Tanks. None. Roof Column

Module 4: Storage tank comparison - TANKS 4.0 Demonstration
Gaseous waste stream flowsheet ; pg 37 • Toluene emissions only • 516,600 gal/yr flowrate of toluene • 15,228.5 gallon tank for each comparison Storage Tank Comparison - Tanks 4.0 Demonstration. None. Pollution prevention strategies • replace fixed-roof with floating-roof tank • maintain light-colored paint in good condition • heat tank to reduce temperature fluctuations

Module 4: Fugitive Sources - pollution prevention techniques
Fugitive Sources - Pollution Prevention Techniques. None

Module 4: Flowsheet evaluation - maleic anhydride from n-butane
Flowsheet Evaluation - Maleic Anhydride from n-Butane. None. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 15, pp

Module 4: Reaction rate parameters - Maleic anhydride from n-butane
Principal Reaction 1. C4H O2  C4H2O3 + 4H2O -DHR,1 = 1.26x106 kJ/kmole 2. C4H O2  4CO + 5H2O -DHR,2 = 1.53x106 kJ/kmole 3. C4H O2  4CO 2 + 5H2O -DHR,3 = 2.66x106 kJ/kmole Activation Energies Rate Equations E1/R = 8,677 K E2/R = 8,663 K E3/R = 8,940 K Reaction Rate Parameters - Maleic Anhydride from n-Butane. None. Schneider et al. 1987, “Kinetic investigation and reactor simulation…”, Ind. Eng. Chem. Res., Vol. 26,

Module 4: Fixed-bed reactor section - 100 MM tons/yr maleic anhydride process
Fixed-Bed Reactor Section 100 MM tons/yr Maleic Anhydride Process. None.

Module 4: Case Study - reactor temperature: Maleic anhydride from n-butane
Case Study - Reactor Temperature: Maleic Anhydride from n-Butane. None.

Module 4: Summary/Conclusions
1. Methodologies/software tools - process synthesis: • emission factors • surrogate process information from historical sources • emission estimation software: TANKS 4.0, AirCHIEF 7.0, process simulator packages, • Tier 2 environmental assessment 2. Case studies: • VOC recovery/recycle from a gaseous waste stream - effects of MSA choice on energy consumption • Maleic anhydride from n-butane - effect of reaction temperature on conversion, MA yield, MA selectivity Summary/Conclusions. None.

Module 5: Process Integration of Heat and Mass Chapter 10
David R. Shonnard Department of Chemical Engineering Michigan Technological University

The environmental performance of a process depends on both the performance of the individual unit operations, but also on the level to which the process steams have been networked and integrated Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Review of heat integration concepts Introduction to the tools of mass integration and synthesis of mass exchange networks - Chapter 10 Cast study - heat integration of the MA flowsheet

Students will: learn about efficient utilization of waste streams as raw materials through application of source/sink mapping are introduced to graphical tools of mass exchange network synthesis, composition interval diagrams and load line diagrams. apply mass exchange network synthesis to simple flowsheets

Mass/energy balance course: • dilute contaminant balance calculations around process units • source/sink matching of energy streams Continuous/stagewise separations course: • applications to in-process recovery and recycle of contaminants Design course: • graphical design tools for mass integration of waste streams

Module 5: Analogies between process heat and mass integration
Heat Integration the optimum use of heat exchangers and streams internal to the process to satisfy heating and cooling requirements. Tools: 1. Temperature interval diagram 2. Heat load diagram (pinch diagram) Mass Integration the optimum use of mass exchangers and streams internal to the process to satisfy raw material requirements, maximize production and minimize waste generation (water recycle/reuse applications). Tools: 1. Source/sink mapping and diagrams 2. Composition interval diagram 3. Mass load diagram (pinch diagram)

Module 5: Heat exchange networks - key features
T - Heat Load Diagram • composite curves • pinch analysis • minimum external utilities Heat exchange network • internal • external [(mCp)1 + (mCp) 2]-1 89% reduction in external utilities Seider, Seader, and Lewin, 1999, “Process Design Principles”, John Wiley & Sons, Ch. 7

Module 5: Heat exchange networks - Illustrative example - before heat integration
per sec 1 kg/s, Cp = 1 kJ/(kg-˚C) 2 kg/s, Cp = 1 kJ/(kg-˚C) per sec

Module 5: Heat exchange networks - Temperature - load (pinch) diagram
per sec Placement of each load line vertically is arbitrary 2 kg/s Cooling load for external network, 160 kJ/s Heat transfer load by internal network, 140 kJ/s 1 kg/s Heating load for external network, 30 kJ/s 10 ˚C minimum temperature difference defines the pinch

Module 5: Heat exchange networks - Illustrative example after heat integration
82.4% reduction in cooling utility per sec 140 kJ/s transferred 46.7% reduction in heating utility per sec

Module 5: Mass integration: objectives and methods
objective is to prepare source streams to be acceptable to sink units within the process or to waste treatment 1. Segregation avoid mixing of sources 2. Recycle direct sources to sinks 3. Interception selectively remove pollutants from source 4. Sink/generator manipulation adjust unit operation design or operation Pollutant-rich streams Pollutant-lean streams El-Halwagi, M.M.1997, “Pollution Prevention Through Process Integration: Systematic Design Tools”, Academic Press

Module 5: Motivating example: Chloroethane process before mass integration
Mass balance in terms of CE, the minor component Objective is to reduce the concentration of CE sent to biotreatment to < 7 ppm and a load of < 1.05x10-6 kg CE/s El-Halwagi, M.M.1997, “Pollution Prevention Through Process Integration: Systematic Design Tools”, Academic Press

Module 5: Motivating example: Chloroethane process after mass integration
Interception CE load to biotreatment = 2.5x10-7 kg/s Recycle El-Halwagi, M.M.1997, “Pollution Prevention Through Process Integration: Systematic Design Tools”, Academic Press

Module 5: Mass Integration Tools: Source-sink mapping
the purpose of source-sink mapping is to determine if waste streams can be used as feedstocks within the process - direct recycle Recycle source “a” directly A range of acceptable flowrates and composition for each sink , “S” or mix sources “b” and “c” to achieve the target flowrate - composition using a Lever Rule - like calculation El-Halwagi, M.M.1997, “Pollution Prevention Through Process Integration: Systematic Design Tools”, Academic Press

Module 5: Source-sink mapping: acrilonitrile (AN) process before recycle
0 ppm NH3 0 ppm AN required ≤ 10 ppm NH3 may contain AN 450 ˚C, 2 atm 2-phase stream always with 1 kg/s H2O but no H2O in the AN layer mass fraction of AN always equal to 0.068 NH3 equilibrium CW = 4.3 CAN NH3 partitioning CSTEAM = 34 CPRODICT

Module 5: Source-sink map acrilonitrile (AN) process
Sinks for water Sources for water

Module 5: Flow rates of condenser and fresh water sent to Scrubber

Module 5: Mass balances on AN units for remaining flow rates and compositions
Aqueous streams from condenser and distillation column 4.7 kg/s H2O 0.5 kg/s AN 12 ppm NH3 From fresh water supply 1.0 kg/s H2O 0 kg/s AN 0 ppm NH3 Scrubber Gas stream from condenser 0.5 kg/s H2O 4.6 kg/s AN 39 ppm NH3 to decanter ? kg/s H2O ? kg/s AN ? ppm NH3

Module 5: Flow rates and compositions from Scrubber to Decanter
And similarly for other units

acrilonitrile (AN) process after recycle
freshwater feed 30% of original AN production rate increased by 0.5 kg/s; $.6/kg AN and 350 d/yr = $9MM/yr rate of AN sent to biotreatment is 85% of original 60% of original

Module 5: Mass exchange network (MEN) synthesis
1. Similar to heat exchange network (HEN) synthesis 2. Purpose is to transfer pollutants that are valuable from waste streams to process streams using mass transfer operations (extraction, membrane modules, adsorption, .. 3. Use of internal mass separating agents (MSAs) and external MSAs. 4. Constraints i. Positive mass transfer driving force between rich and lean process streams established by equilibrium thermodynamics ii. Rate of mass transfer by rich streams must be equal to the rate of mass acceptance by lean streams iii. Given defined flow rates and compositions of rich and lean streams

Module 5: Mass integration motivating example - Phenol-containing wastewater
El-Halwagi, M.M.1997, “Pollution Prevention Through Process Integration: Systematic Design Tools”, Academic Press Outlet streams for recycle or sale Mass separating agents to waste water treatment - Minimize transfer to waste treatment - to wastewater treatment

Module 5: Outline of MEN synthesis
1. Construct a composition interval diagram (CID) 2. Calculate mass transfer loads in each composition interval 3. Create a composite load line for rich and lean streams 4. Combine load lines on a combined load line graph 5. Stream matching of rich and lean streams in a MEN using the CID

Equilibrium of pollutant between rich and lean streams
Module 5: Hypothetical set of rich and lean streams - stream properties Equilibrium of pollutant between rich and lean streams y = 0.67 x

Module 5: Composition interval diagram - a tool for MEN synthesis
x scale matched to y scale using y = 0.67 x

Module 5: Mass transfer loads in each interval
Rich Streams negative mass load denotes transfer out of the stream

Module 5: Composite load line for the rich stream
Region 1 & 2 Region 3 Region 4 Region 5

Module 5: Combined load line for rich and lean streams
mass load to be added to lean stream externally mass load to be transferred internally Rich Stream can be moved vertically mass load to be removed from rich stream by external MSA

Module 5: Stream matching in MEN synthesis

Module 5: Heat integration of the MA flowsheet
-9.23x107 Btu/hr 2.40x107 Btu/hr 9.70x107 Btu/hr Reactor streams generate steam -4.08x107 Btu/hr Without Heat Integration

Module 5: Heat integration of reactor feed and product streams

Module 5: Heat integration of absorber outlet and recycle streams

Module 5: Maleic anhydride flowsheet with heat integration

Module 5: Heat integration summary
Greater energy reductions are possible when steam generated from the reactors is used for the reboiler, purge and feed heaters 76.8% reduction 27.4% reduction

Module 5: Recap Educational goals and topics covered in the module
Potential uses of the module in chemical engineering courses Review of heat integration concepts Introduction to the tools of mass integration and synthesis of mass exchange networks - Chapter 10 Cast study - heat integration of the MA flowsheet

Module 6: Flowsheet Environmental Impact Assessment Chapter 11
David R. Shonnard Hui Chen Department of Chemical Engineering Michigan Technological University Introduction. At this point Dr. Shonnard asked for the participants comments on a proposed method to present the green engineering curriculum. Dr. Shonnard has developed an interactive WebPage for Chapter 13 of the Green Engineering text book. This WebPage can be used to present the course material and sample problems. To view this WebPage, first insert the CD that accompanies the text. Go to My computer click on the correct drive, now click on DFE, and LCA (life cycle assessment). Please review the WebPage and provide feedback on the usefulness of this site. EPA is planning on developing a series of WebPages for each chapters to make teaching the chapters easier. Each WebPage will include an introductory video that describes the chapter, provide the chapter outline or lecture notes, and include addition links or tools. The WebPage would also include a series of problems as well as sample reports, and open ended homework problems. Additionally students could access a variety of links from this web page. Carnegie Melon has a Economic Assessment tool that can be used to construct models that follow money through the economy, this link is presented on the Chapter 13 WebPage. (For example, if 1 million dollars is spent on automobiles then this system would calculate the amount spent on iron, steel, plastics, etc., and for each of these it calculates the amount spent on fuel and ore. The system also tracts environmental factors throughout the economy (SO2 emissions, electric usage, wastes, etc.). This a good tool to use with home work assignments.

After the flowsheet input output structure, unit operation designations, and mass/heat integration have been completed, the last step in the process to improve the environmental performance of a chemical process design is to perform a detailed environmental impact assessment Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Review of environmental impact assessment methods Application of Tier 3 environmental impact assessment to a detailed flowsheet - Chapter 11 Presentation Outline. None

Students will: learn to apply a systematic risk assessment methodology to the evaluation of chemical process designs integrate emission estimation, environmental fate and transport calculation, and relative risk assessment to rank process design alternatives Education Goals and Topics. None

Process Design course: • develop and use environmental objective functions to rank process design alternatives • rank process designs quantitatively based on environmental criteria Transport phenomena course: • Module on interphase mass transfer in the environment Potential Uses of the Module in Chemical Engineering Courses. None

Module 6: Essential features of environmental impact assessment for chemical process design
Computationally efficient  Environmental performance metrics quickly calculated using output from commercial process simulators Link waste generation and release to environmental impacts  Environmental metrics linked to process parameters Impacts based on a systematic risk assessment methodology  Release estimates  fate and transport  exposure  risk Essential Features of Environmental Impact Assessment for Chemical Process Design. None

Module 6: Systematic risk assessment methodology
National Academy of Sciences, 1983 1. Hazard Identification (which chemicals are important?) 2. Exposure assessment (release estimation, fate and transport, dose assessment) 3. Toxicity assessment (chemical dose - response relationships) 4. Risk Characterization (magnitude and uncertainty of risk) Result: Quantitative risk assessment (e.g. excess cancers) Atmospheric dispersion Model, Ca Systematic Risk Assessment Methodology. This slide represents single compartment atmospheric dispersion. Thibodeaux, L.J. 1996, Environmental Chemodynamics, John Wiley & Sons

Module 6: Quantitative risk calculation
Carcinogenic Risk Example (inhalation route) Exposure Dose Dose - Response Relationship, Slope Factor Quantitative Risk Calculation. This equation is used to calculate the number of excess cancers per 1 million cases in the population where: Ca = Concentration CR = Contact rate EF = Exposure Frequency ED = Exposure Duration BW = Body weight AT = Length of exposure, typically 70 years expressed in terms of days SF = Slope Factor Result: # excess cancers per 106 cases in the population; 10-4 to 10-6 acceptable Disadvantage: Only a single compartment is modeled / Computationally inefficient Highly uncertain prediction of risk

Module 6: Relative risk calculation
Carcinogenic Risk Example (inhalation route) Relative Risk Calculation. In this equation, used to calculate relative risk, the exposure factors cancel out and all that remains is the concentration in air multiplied by the slope factor. A disadvantage of this method is that it lacks mathematical rigor; however, this can also be seen as an advantage because it is a relatively simple equation. Result: Risk of a chemical relative to a well-studied benchmark compound Advantage: If C is calculated for all compartments using a multimedia compartment model, computationally efficient

Module 6: Tier 3 Relative risk index formulation
Chemical Specific Exposure Potential Inherent Impact Parameter Benchmark Compound Chemical “i” Tier 3 Relative Risk Index Formulation. For the Chemical specific calculations the exposure potential is the concentration of the chemical in air multiplied by the carcinogenic slope factor (see previous slide) for chemical “i” divided by the exposure potential of the benchmark chemical multiplied by the Inherent Impact parameter (e.g., carcinogenic slope factor) for the bench mark chemical. The chemical specific calculation is a more general statement that the calculation of the process index. The process index is the calculated Risk Index for all chemicals related to the process multiplied by the emission rate of that chemical. One can convert the emission rate for a unique chemical to the benchmark release and use that data for health effects analyses. Process Emission Rate of Chemical, i

Module 6: Airborne emissions estimation
Unit Specific EPA Emission Factors Distillation/stripping column vents Reactor vents Fugitive sources Correlation (AP- 42, EPA) Storage tanks, wastewater treatment Fugitive sources (pumps, valves, fittings) Criteria Pollutants from Utility Consumption Factors for CO2, CO, SO2, NOx, AP- 42 (EPA) factors Process Simulators (e.g. HYSYS) Airborne Emissions Estimation. None

Module 6: Release estimates based on surrogate processes
Waste stream summaries based on past experience 1. Hedley, W.H. et al. 1975, “Potential Pollutants from Petrochemical Processes”, Technomics, Westport, CT 2. AP-42 Document, Chapters 5 and 6 on petroleum and chemical industries, Air CHIEF CD, 3. Other sources i. Kirk-Othmer Encyclopedia of Chemical Technology, 1991- ii. Hydrocarbon Processing, “Petrochemical Processes ‘99”, March 1999. Release Estimates Based on Surrogate Processes. None.

Module 6: Multimedia compartment model formulation
Processes modeled • emission inputs, E • advection in and out, DA • intercompartment mass transfer, Di,j • reaction loss, DR Model Domain Parameters • surface area km2 • 90% land area, 10% water • height of atmosphere - 1 km • soil depth - 10 cm • depth of sediment layer - 1 cm • multiphase compartments Multimedia Compartment Model Formulation. The multimedia compartment model formulation was developed approximately 20 years ago. The model domain parameters discussed in the box below the multimedia compartment model represent a box model. The soil depth effects the transport of substances. The discussion of multiphase compartments includes gas, water, and solid phases (sediment and soil). The processes modeled include emission inputs, which are the emissions released to the air, soil, and water. The intercompartment mass transfer coefficient is diffusion based, in this case, however it may be convection based. The reaction loss is related to the oxidation for removal of the pollutant. The source presented at the bottom of the slide is a good source for modeling. Mackay, D. 1991, ”Multimedia Environmental Models", 1st edition,, Lewis Publishers, Chelsea, MI

Module 6: Multimedia compartment model input data
Multimedia Compartment Model Input Data. This table presents typical inputs/environmental properties associated with modeling. The spreadsheet location gives the location of this data from the Mackay spreadsheet provided in the CD-ROM. The data show that benzene, ethanol, and PCP should all behave differently when released into the atmosphere.

Module 6: Multimedia compartment model typical results
Multimedia Compartment Model Typical Results. This slide shows the behavior of different chemicals based on their properties and a rate process at steady state.

Module 6: Multimedia compartment model typical results - interpretations
1. The percentages in each environmental compartment depend upon the emission scenario a) the highest air concentrations result from emission into the air b) the highest water concentrations are from emission into water c) the highest soil concentrations are from emission into soil d) highest sediment concentrations are from emission into water 2. Chemical properties dictate percentages and amounts a) high KH results in high air concentrations b) high KOW results in high soil concentrations c) high reactions half lives results in highest pollutant amounts Multimedia Compartment Model Typical Results - Interpretations. None.

Module 6: Nine Environmental Impact / Health Indexes
Nine Environmental Impact Health Indexes. These equations should be used for detailed environmental matrix formation. Chapter 11 of the Green Engineering textbook shows how these equations were developed. Global Warming: Over 50 chemicals have data associated with the global warming index. Ozone Depletion: The ODP was developed for a small number of chemicals they are not aware of another estimation tool associated with this index. Smog Formation: MIRi is the maximum incremental reactivity of a specific chemical based on the photochemical properties of the reactive chemicals (Number of ozones emitted by a single VOC) ROG is the reactive organic gas, an average of VOCs were used for the benchmark. Data are associated with between 200 and 250 chemicals. Acid Rain. ARP is only known for a small number of chemicals.

Module 6: Nine Environmental Impact / Health Indexes
Nine Environmental Impact/Health Indexes. This table presents two groups of human health toxicity carcinogenic and non-carcinogenic as well as ecosystem toxicity (fish toxicity). These equations represent multiple environmental impacts.

. . . . . . . . . . . . . . . . . . . . Process Simulator Output
or Conceptual Design List of Chemicals, Equipment specifications, Utility consumption, Annual throughput EFRAT Physical Properties, Toxicology, Weather, Geographical, and Emission Factors Databases Chemicals, Equipment specifications, annual throughput Chemicals, KH, KOW Chemicals, t, LC50, HV, MIR… Air Emission Calculator Chemical Partition Calculator Relative Risk Index Calculator Emission Rate Process Simulator Output or Conceptual Design. None. Chemical I1 I2 In Report A B C n MS Excel® Multi-Criteria Decision Analysis

Module 6: Software tools for environmental impact assessment of process designs
Environmental Fate and Risk Assessment Tool (EFRAT) • links with HYSYS for automated assessments WAste Reduction Algorithm (WAR) • reported to be linked with ChemCAD • US EPA National Risk Management Research Laboratory Cincinnati, OH Dr. Heriberto Cabezas and Dr. Douglas Young US Environmental Protection Agency National Risk Management Research Laboratory 26 W. Martin Luther King Dr. Cincinnati, OH 45268 Software Tools for Environmental Impact Assessment of Process Designs. EFRAT uses the nine weighted environmental indices.

Module 6: Absorption - distillation process: analysis of an existing separation sequence
Absorption-Distillation Process Analysis of an Existing Separation Sequence. This slide presents pollution prevention activities which recover VOC compounds and sends them back for processing. The decision must be made how much pollution should be prevented versus how much should be controlled. HYSYS Flowsheet

Module 6: Unit-specific emission summary
Unit-Specific Emission Summary. This slide presents the unit operation, the associated flow rate and the types and amounts of chemicals emitted based on the question and data presented on the previous slide. 100 kgmole/hr Oil Flow Rate; Oil Temperature = 82˚F; DT=180˚F Where are the centers for energy consumption and emissions?

Module 6: Risk index summary
Risk Index Summary. Each of these indices represent the nine environmental indices discussed on the previous slides (e.g., GW = Global Warming). From this table one can see the chemicals with the highest impact index. For example; for the first category NOx has the highest impact index. Which chemicals have the highest impact indexes?

Module 6: Process environmental summary
100 kgmole/hr Oil Flow Rate; Oil Temperature = 82˚F; DT=180˚F Process Environmental Summary. This slide presents how to calculate the process index based on the data gathered on slide 22. When looking at this table keep in mind that a process index of zero does not necessarily mean the index is zero. Zero was used as a place holder for chemicals without actual data. In each of the two tables the Process Index with the highest overall impact is shaded.

Module 6: VOC recovery by absorption into tetradecane (C14)
VOC Recovery by Absorption into Tetradecane (C14). The data on this graph indicates that tetradecane is very good at removing toluene at most flow rates but needs to be at a relatively high flow rate to remove both VOCs.

Module 6: Environmental index profiles
Environmental Index Profiles. This graph indicates that VOC releases are zero for ISF at a relatively low flow rate. IFT, IINH and IAR all decrease as flow increases. However IGW and IAR increase as flow rate increases.

Module 6: Interpretation of environmental assessment results
Risk reductions at 50 kgmole/hr flow rate  Global Warming Index - 41% reduction  Smog Formation Index - 86 % reduction  Acid Rain Index - small increase  Inhalation Route Toxicity Index - 78 % reduction  Ingestion Route Toxicity Index - 18 % reduction  Ecotoxicity (Fish) Index - 19 % reduction Absorber oil choice is not an optimum  Oil selectively absorbs toluene, but ethyl acetate has a higher value Multiple indexes complicate the decision Interpretation of Environmental Assessment Results. This slide summarizes the information presented on the previous graphs. This helps provide a complete picture of the options. The acid rain index sees a small increase because of the increased energy requirements.

Module 6: Maleic anhydride from n-butane process flowsheet evaluation
Use of EFRAT : evaluate the MA process Basecase (Dibutyl phthalate absorber oil) with and without heat integration Simulate 3 case studies using heat integrated flowsheet Dibutyl phthalate absorber oil Dibenzyl ether absorber oil Diethylene glycol butyl ether acetate absorber oil Maleic Anhydride from n-butane Process Flowsheet Evaluation. Module 5, page 24 has a figure to refer to for this process. To use EFRAT you must first install the SCENE software from the Green Engineering Disk that came with the draft textbook. Go to SCENE on your CD-ROM. Click on Setup. Follow the directions for installing the software (enter the serial number from readme.txt). Once you have installed the software go to the start menu and go to CPAS Programs and then click on SCENE. Now open an existing case by going to your CD-ROM and opening the following directory GEEW/SCENE/CASES/CASE2/ now open tempcase.ced. Continue following the directions for the exercise, presented on page 5 in the beginning of the draft textbook.

Module 6: Maleic anhydride from n-butane: Use of EFRAT on basecase flowsheet
Follow the tutorial instructions given in the notebook! The SCENE file has been linked to a HYSYS case file Add three additional emission sources Complete the relative risk assessment calculations Maleic anhydride from n-butane: Use of EFRAT on Basecase Flowsheet. None.

Module 5: Heat integration of the MA flowsheet
-9.23x107 Btu/hr 2.40x107 Btu/hr 9.70x107 Btu/hr Reactor streams generate steam Maleic Anhydride from n-butane: Effects of Absorber Oil Choice. This slide compares the environmental metrics associated with the absorber oil choice. The three different absorber oils are presented as well as the relative risk indices associated with each oil. -4.08x107 Btu/hr Without Heat Integration

Module 5: Maleic anhydride flowsheet with heat integration
Not presented at Workshop.

Module 6: Maleic anhydride from n-butane: effect of heat integration on risk indexes
72.2% reduction Remaining Indexes are unchanged Not presented at Workshop. 30.4% reduction

Module 6: Maleic anhydride from n-butane: effects of absorber oil choice
42.1% reduction 16.3% reduction 85.1% reduction 81.7% reduction Not presented at Workshop.

Module 6: Summary / Conclusions
Educational goals and topics covered in the module Potential uses of the module in chemical engineering courses Review of environmental impact assessment methods Application of Tier 3 environmental impact assessment to a detailed flowsheet - Chapter 11 Heat integration of the Maleic Anhydride flowsheet Effects of absorber oil choice for the MA flowsheet Summary/Conclusions. None

David Shonnard Department of Chemical Engineering

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