1. CHEN 4460 – Process Synthesis, Simulation and Optimization Dr. Mario Richard Eden Department of Chemical Engineering Auburn University Lecture No. 1 – The Design Process August 21, 2006 Contains Material Developed by Dr. Daniel R. Lewin, Technion, Israel Class Overview & Introduction

2. Lectures (Start Today) –Monday 9:00 – 9:50 AM (Haley Center 2213) –Additional recitation lectures during lab sessions Labs (Start Next Week) –Sections I: Tuesday & Thursday 11:00 AM - 12:20 PM (AERO 0123) II: Tuesday & Thursday 6:30 PM - 7:45 PM (AERO 0123) Large part of labs consist of multimedia based instruction Headphones will be available upon request (ordered) Homework –Assigned for both lecture and lab parts (with overlap) –Several homework assignments can/should be solved using Aspen Class Overview 1:3

3. Teaching Assistants –Ms. Urvi Kothari –Ms. Wei (Vivi) Yuan –Office hours and location will be announced shortly Course Materials –Textbook Seider, W. D., J. D. Seader, and D. R. Lewin, “Product and Process Design Principles”, 2. edition Wiley (2004). Eden, M. R., Abdelhady A. "ASPEN Lab Notes", Auburn University (2006) (Will be available at Engineering Learning Resources Center soon). Class Overview 2:3

4. Grading –Simulation Project (10%) –Homework (20%) –Midterm (20%) –Final exam (50%) Instructors Office Hours –Official: Monday 1:00 – 3:00 PM –Reality: Any time the door is open Class Restructuring –Deficiencies identified during Senior Design classes –Closer integration between lectures and lab –Smoother transition to Senior Design class Class Overview 3:3

5. Tentative Class Schedule

6. Tentative Lab Schedule MM: Multimedia material to review using headphones at your own pace. MM Tutorials: Perform simulation while following multimedia presentation.

7. Multimedia 1:2 Choice of Simulator Software Aspen Plus Hysys Matlab

8. Multimedia 2:2 Contents Navigation

9. Lecture 1 – Objectives  Be knowledgeable about the kinds of design decisions that challenge process design teams.  Have an appreciation of the key steps in carrying out a process design. This course, as the course text, is organized to teach how to implement these steps.  Be aware of the many kinds of environmental issues and safety considerations that are prevalent in the design of a new chemical process.  Understand that chemical engineers use a blend of hand calculations, spreadsheets, computer packages, and process simulators to design a process.

10. Lecture 1 – Outline Primitive Design Problems –Example Steps in Designing/Retrofitting Chemical Processes –Assess Primitive Problem –Process Creation –Development of Base Case –Detailed Process Synthesis - Algorithmic Methods –Process Controllability Assessment –Detailed Design, Sizing, Cost Estimation, Optimization –Construction, Start-up and Operation Environmental Protection Safety Considerations

11. Primitive Design Problems The design or retrofit of chemical processes begins with a desire to produce profitable chemicals that satisfy societal needs in a wide range of areas: Partly due to the growing awareness of the public, many design projects involve the redesign, or retrofitting, of existing chemical processes to solve environmental problems and to adhere to stricter standards of safety. –petrochemicals –petroleum products –industrial gases –foods –pharmaceuticals –polymers –coatings –electronic materials –bio-chemicals

12. Origin of Design Problems Often, design problems result from the explorations of chemists, biochemists, and engineers in research labs to satisfy the desires of customers to obtain chemicals with improved properties for many applications. However, several well-known products, like Teflon (poly- tetrafluoroethylene), were discovered by accident. In other cases, an inexpensive source of a raw material(s) becomes available. Yet another source of design projects is the engineer himself, who often has a strong inclination that a new chemical or route to produce an existing chemical can be very profitable.

13. Steps in Process Design Assess Primitive Problem Detailed Process Synthesis - Algorithmic Methods Development of Base-case Plant-wide Controllability Assessment Detailed Design, Equipment sizing, Cap. Cost Estimation, Profitability Analysis, Optimization

14. Steps in Process Design Assess Primitive Problem Development of Base-case Detailed Process Synthesis - Algorithmic Methods Plant-wide Controllability Assessment Detailed Design, Equipment sizing, Cap. Cost Estimation, Profitability Analysis, Optimization SECTION A

15. Steps in Process Design

16. Assess Primitive Problem Process design begins with a primitive design problem that expresses the current situation and provides an opportunity to satisfy a societal need. The primitive problem is examined by a small design team, assessing possibilities, refining the problem statement, and generating more specific problems: –Raw materials - available in-house, can be purchased or need to be manufactured? –Scale of the process (based upon a preliminary assessment of the current production, projected market demand, and current and projected selling prices) –Location for the plant Brainstorming to generate alternatives.

17. Example: VCM Manufacture To satisfy the need for an additional 800 MMlb/yr of VCM, the following plausible alternatives might be generated: –Alternative 1. A competitor’s plant, which produces 2 MMM lb/yr of VCM and is located about 100 miles away, might be expanded to produce the required amount, which would be shipped. In this case, the design team projects the purchase price and designs storage facilities. –Alternative 2. Purchase and ship, by pipeline from a nearby plant, chlorine from the electrolysis of NaCl solution. React the chlorine with ethylene to produce the monomer and HCl as a byproduct. –Alternative 3. The company produces HCl as a byproduct in large quantities, thus HCl is normally available at low prices. Reactions of HCl with acetylene, or ethylene and oxygen, could produce 1,2- dichloroethane, an intermediate that can be cracked to produce vinyl chloride.

18. Survey Literature Sources SRI Design Reports Encyclopedias –Kirk-Othmer Encyclopedia of Chemical Technology (1991) –Ullman’s Encyclopedia of Industrial Chemistry (1988) –... Handbooks and Reference Books –Perry’s Chemical Engineers Handbook (1997) –CRC Handbook of Chemistry and Physics –... Indexes –See Auburn University Library Patents Internet

19. Steps in Process Design Assess Primitive Problem Development of Base-case Plant-wide Controllability Assessment Detailed Design, Equipment sizing, Cap. Cost Estimation, Profitability Analysis, Optimization Detailed Process Synthesis - Algorithmic Methods SECTION B

20. Steps in Process Design

21. Assess Primitive Problem Development of Base-case Detailed Process Synthesis - Algorithmic Methods Detailed Design, Equipment sizing, Cap. Cost Estimation, Profitability Analysis, Optimization SECTION C Plant-wide Controllability Assessment

22. Steps in Process Design

23. Environmental Issues 1:2 Handling of toxic wastes –97% of hazardous waste generation by the chemicals and nuclear industry is wastewater (1988 data). –In process design, it is essential that facilities be included to remove pollutants from waste-water streams. Reaction pathways to reduce by-product toxicity –As the reaction operations are determined, the toxicity of all of the chemicals, especially those recovered as byproducts, needs to be evaluated. –Pathways involving large quantities of toxic chemicals should be replaced by alternatives, except under unusual circumstances. Reducing and reusing wastes –Environmental concerns place even greater emphasis on recycling, not only for unreacted chemicals, but for product and by-product chemicals, as well. (i.e., production of segregated wastes - e.g., production of composite materials and polymers).

24. Environmental Issues 2:2 Avoiding non-routine events –Reduce the likelihood of accidents and spills through the reduction of transient phenomena, relying on operation at the nominal steady-state, with reliable controllers and fault-detection systems. Design objectives, constraints and optimization –Environmental goals often not well defined because economic objective functions involve profitability measures, whereas the value of reduced pollution is often not easily quantified economically. –Solutions: mixed objective function (“price of reduced pollution”), or express environmental goal as “soft” or “hard” constraints. –Environmental regulations = constraints

25. Safety Issues Flammability Limits of Liquids and Gases LFL and UFL (vol %) in Air at 25 o C and 1 Atm These limits can be extended for mixtures, and for elevated temperatures and pressures. With this kind of information, the process designer makes sure that flammable mixtures do not exist in the process during startup, steady-state operation, or shut-down.

26. Design for Safety Techniques to Prevent Fires and Explosions –Inerting - addition of inert dilutant to reduce the fuel concentration below the LFL –Installation of grounding devices and anti-static devices to avoid the buildup of static electricity –Use of explosion proof equipment –Ensure ventilation - install sprinkler systems Relief Devices Hazard Identification and Risk Assessment –The plant is scrutinized to identify sources of accidents or hazards. –Hazard and Operability (HAZOP) study is carried out, in which all of the possible paths to an accident are identified. –When sufficient probability data are available, a fault tree is created and the probability of the occurrence for each potential accident computed.

27. Summary – The Design Process Steps in Designing and Retrofitting Chemical Processes –Assess Primitive Problem – Covered Today (SSL pp. 3-41) –Process Creation – Next Week (SSL pp. 62-85, 96-105) –Development of Base Case –Detailed Process Synthesis - Algorithmic Methods –Process Controllability Assessment –Detailed Design, Sizing, Cost Estimation, Optimization –Construction, Start-up and Operation Environmental Protection –Environmental regulations = design constraints Safety Considerations –Should strive to design for “inherently safe plants”

28. Final Comments Capabilities upon Completion of this Class –How to simulate complete flowsheets and predict their performance. –How to identify best achievable performance targets for a process WITHOUT detailed calculations. –How to systematically enhance yield, maximize profit, maximize resource conservation, reduce energy, and prevent pollution? –How to debottleneck a process? –How to choose units and screen their performance? –How to understand the BIG picture of a process and use it to optimize any plant? –And much more…..