I Basic Concept of Process Design

  I Basic Concept of Process Design Dr.Eng. Yulius Deddy Hermawan Department of Chemical Engineering UPN “Veteran” Yogyakarta Outline

  1. Formulation of The Design Problem

  2. Chemical Process Design and I ntegration

  3. The Hierarchy of Chemical Process Design

  4. Onion Model

  5. Batch and Continuous Processes

  6. Capacity Estimation

  7. Pretreatment of Raw Materials Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  I FORMULATI ON OF THE DESI GN PROBLEM How does Chemical Process Plant come into being?

1. An idea:

  a. Completely new product

  b. I mprovement of an existing product

  2. Feasibility Study: reasonable profit?

  3. Research and Development: collect data (information) such as the operating condition (P, T, F)

  4. Process Design: in this step, a Chemical Engineer:

  a. decides what kind of equipments will be needed for each operation b. calculates size of each item

  

c. organizes all information in the flow sheet (PFD and/ or P&I D)

  5. Project Engineering: pilot plant and full scale

  6. Construction Engineering

  7. Market Research Engineering

  Formulation of The Design Problem Need product Operating and specification:

reacting condition

  Purify spec.

  Recycle, heat integration

Process

Design

  Flowsheet

Design

Problem for a specialty product (the functional properties rather Capacity, energy than chemical properties): require a product design stage _{Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY}

  Chemical Product (Smith, R, 2005) essential to modern living standards

• almost all aspects of everyday life are supported by
• chemical products in one way or another.

  3 broad classes of chemical product:

• 1. Commodity or bulk chemicals:

  2. Fine chemicals:

  3. Specialty or effect or functional chemicals

  Commodity or Bulk Chemicals (Smith, R, 2005)

  These are produced in large volumes and purchased on the basis of chemical composition, purity and price.

  Examples are: sulfuric acid,

   

  nitrogen,

   oxygen,

   ethylene and chlorine.

   Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY Fine Chemicals

  (Smith, R, 2005)

  These are produced in small volumes and purchased on the basis of chemical composition, purity and price.

  Examples: chloropropylene oxide: used for the manufacture of epoxy

• resins, ion-exchange resins and other products dimethyl formamide: used, for example, as a solvent,
• reaction medium and intermediate in the manufacture of pharmaceuticals n-butyric acid: used in beverages, flavorings, fragrances
• and other products) barium titanate powder: used for the manufacture of
• electronic capacitors
• Pharmaceuticals

• Pesticides
• Dyestuffs
• perfumes
• flavorings.

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY Specialty or effect or functional chemicals

  (Smith, R, 2005) These are purchased because of their effect (or function), rather than their chemical composition.

  Examples:

  I I CHEMI CAL PROCESS DESI GN AND I NTEGRATI ON

  Chemical Process Design and I ntegration (Smith, R, 2005)

  of raw material into desired products

• Transformat ion

  usually can not be achieve in a single step, but trough some steps as follows:

  1. Reaction

  2. Separation

  3. Mixing

  4. Heating

  5. Cooling

  6. Pressure change

  7. Particle size reduction and enlargement _{Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY} 8. etc.

  Chemical Process Design and I ntegration (Smith, R., 2005)

  of chemical process involves two broad activities:

• Synt hesis

  1. Selection of individual transformation step

  2. I nterconnect individual transformation step to form complete structures that achieves the required overall transformation.

  : diagrammatic representation of the process

• Flow sheet steps with their interconnection.

  

Once the flowsheet structure has been defined, a simulation of the

process can be carried out. A simulation is a mathematical model of

the process that attempts to predict how the process would behave

if it were constructed.

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  I I I HI ERARCHY OF CHEMI CAL PROCESS DESI GN AND

  I NTEGRATI ON

  Hierarchy of Chemical Process Design and I ntegration (Smith, R, 2005) Process Starts with the reactor.

• The process requires a reactor to transform the FEED into
• PRODUCT Unfortunately, not all the FEED reacts.

  Also, part of the FEED reacts to form BYPRODUCT instead of the desired PRODUCT.

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY Hierarchy of Chemical Process Design and I ntegration

  A separation system is needed to isolate the PRODUCT at the required purity.

  Reactor design dictates the

• separation and recycle problem this flowsheet is probably too
>inefficient in its use of energy Need heat integration

  For a given reactor and separator design there are different possibilities for heat integration.

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY For a given reactor and separator design there are different possibilities for heat integration.

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY Changing the reactor dictates a different separation and recycle problem

  A different reactor design not only leads to a different separation system but additional possibilities for heat integration.

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY A different reactor design not only leads to a different separation system but additional possibilities for heat integration.

  I V ONI ON MODEL

  Simplify Onion Model

  (Smith, R, 2005)

  I I I

  I I Raw materials

  Products

  I I . Process/ Reaction

  I I . Operation

  I I I . Utility Reflect !!

  1. What does it mean? Process’ circle < operation circle < utility circle 2. in case, if I ndustries do not involve the process/ reaction? How about the onion model?

  3. Does it possible if industries with un-concentred the onion model? Give its _{Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY} examples

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  V BATCH & CONTI NUOUS PROCESSES

  Batch and Continuous Processes (Smith, R, 2005) However, not all processes operate continuously.

• I n a batch process, the main steps operate discontinuously.
• I n contrast with a continuous process, a batch process does
• not deliver its product continuously but in discrete amounts. This means that heat, mass, temperature, concentration and other properties vary with time. I n practice, most batch processes are made up of a series of
• batch and semicontinuous steps.

  A semicontinuous step runs continuously with periodic start-

• ups and shutdowns.

  Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY ess A Simple Batch Proc

  (Smith, R, 2005) Unfortunately, even if the reactor effluent is at a high enough temperature to heat the feeding, the reactor feeding and emptying take place at different times, Requires cooling Requires heating

  Batch Processes:

  ( R. Smith) are economical for small volumes;

• are flexible in accommodating changes in product formulation;
• are flexible in changing production rate by changing the
• number of batches made in any period of time; allow the use of standardized multipurpose equipment for the
• production of a variety of products from the same plant; are best if equipment needs regular cleaning because of fouling
• or needs regular sterilization; are amenable to direct scale-up from the laboratory and
• allow product identification.
• Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Batch Processes: ( R. Smith) One of the major problems with batch processing is batch to- batch conformity .

  Minor changes to the operation can mean slight changes

• in the product from batch to batch. Fine and specialty chemicals are usually manufactured in
• batch processes. Yet, these products often have very tight tolerances for impurities in the final product and demand batch-to-batch variation being minimized.

  Batch Processes:

  (James M. Dauglas) Select batch, if:

  1. Production rate

  a. Sometimes batch if less than 10million lb/ year

  b. Usually batch if 1million lb/ year

  c. Multiproduct plant

  2. Market forces:

  a. Seasonal production

  b. Short product lifetime

  3. Scale up problems:

  a. Very long reaction times

  b. Handling slurries at low flowrates

  c. Rapidly fouling materials _{Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY}

VI PLANT CAPACI TY ESTI MATI ON

  Production Capacity (Smith, R, 2005)

  Production capacity is an important factor that needs to be calculated to: determine equipment size

• satisfy contractual requirements
• aid supply chain management
• benchmark against competitors
• obtain operating permits from regulator.
• Production capacity is a central concept in: production planning and scheduling
• operations management
• Production capacity depends on: market
• raw material availability
Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY<
• Production System Performance

  (Smith, R, 2005)

  The production capacity of a chemical plant is a fundamental

• measure of its economic potential. A simple definition of capacity is the maximum through-put
• for a single processing step For chemical manufacturing operations, the production
• system usually takes the form of a series of processing steps (called a serial production system)

  The important things to Determine Production Rates (James M. Dauglas)

  1. I f we want to design a new plant to meet an expanding market condition, first guess of the production rate based on the largest plant that has ever been built.

  The greatest economy of scale

• Normally things are cheaper per unit if we buy them in
• large quantitiies

  2. The maximum size of a plant is usually fixed by the maximum size of one or more pieces of equipment to the plant site.

  3. The production rate specified for the plant might change during a design because of the market conditions are constantly changing

   we must be responsive to these changes

  4. Product purity normally is also fixed by marketing _{Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY} consideration.

  Capacity deppends on the Bottleneck Source: Russell A. Ogle, P.E., and Andrew R. Carpenter, P.E. 2014, AICHE Journal, p. 59 – 63.

  VI I PRETREATMENT OF RAW MATERI ALS Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Raw Material Handling (James M. Dauglas)

  1. Phase:

  a. solid

  b. liquid

  c. gas

  d. slurry

  e. solution f. etc.

  2. I mpurity

  a. inert

  b. will affect to the reactions?

c. I ts separation and recycle

3. I ts Properties:

a. Density/ viscosity

  b. volatility

  c. corrosive d. etc.

4. Operating/ Storing condition: P, T, V.

  Solid Feeder Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Vertical Silo

  Belt Conveyor Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Bucket Elevator

  Liquid Tank Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Mixing Process

  Preparing of Vapor/ Gas Feed Control strategies would be discussed next Dr. Eng. Y. D. Hermawan – ChemEng - UPNVY

  Preparing of High Pressure Gas Feed Control strategies flare (F ) _flare would be discussed next dry gas (F ) _{G SPLITTER high pressure gas} comp. suction _CONDENSOR (F suct ) T, P gas feed (F F ) _{c ondensate (F ) SEPARATOR L COMPRESSOR} coolant (F ) _{C to oil pit}