The document discusses batch and continuous processes. A batch process involves producing a product in stages over workstations, with a finite quantity produced at the end of each stage. Batch processes are commonly used in pharmaceuticals and other industries. Continuous processes involve constant material flow and processing without interruption. Continuous processes are used in capital-intensive industries and have advantages like lower costs and higher quality and consistency. The document also discusses flowcharts which visually represent process sequences and includes examples like swimlane, dataflow, and process flow diagrams.

1. Process Industries-1
Brhane Amha
Chemical engineering
UNIT-1-Fundamentals of chemical manufacture
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2. Batch Vs Continuous Process
Batch Process
•Definition: Batch process is a manufacturing technique in which a product
is created stage by stage over a series of workstations (eg mixers and
stirrers)
•Batch process consists of a sequence of one or more steps that must be
performed in a definite order and at the end of each step finite quantity of
finished product is produced.
•Commonly used in pharmaceutical industry, water purification, inks,
paints, and adhesive industries.
•Batch production is useful in small businesses that cannot afford to run
continuous production lines.
•Good for making seasonal items (shoes, winter clothes etc)
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3. BATCH PROCESS
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4. Batch process
• Advantages: Easier to scale up, more robust, better process control,
single execution.
• Disadvantages: There is idle time between batches (Downtime); Cycle
time becomes a function of lean manufacturing
Cycle time: Time between consecutive batches
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5. Continuous process
• Definition: Continuous process is a flow production method that is
used to manufacture, produce or process materials without
interruption.
• Materials (dry bulk or fluids) are continuously in motion,
undergoing chemical reaction or subjected to mechanical/heat
treatment.
• Process control operations are used to automate variables such as
flow rate, tank levels, pressure, temperature, speed
• Rotating shifts are used.
• Continuous process finds usage in capital intensive industries.
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6. Continuous process
• Each machine operates in single steady state & performs specific
function.
• There is continuous transformation of mass, energy, and
momentum
• Time based process
• Continuous process is stopped for maintenance and irregular
working.
• Continuous processes are used in: compounding, kneading,
shearing, crystallization, encapsulation
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7. Continuous process
• Advantages: Low waste, reduced manufacturing cost; higher and
consistent product quality; improved asset utilization; automation
• Disadvantages: Shutting results in off quality product;
irregularities result in product loss
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8. Continuous process
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9. •Flowcharts are a visual representation of the sequence of events
(steps) needed to perform a process, wherein each step in the
sequence is noted within a diagram.
•Steps are linked by connecting lines and directional arrows.
•Types of Flowcharts:
a) Swimlane Flowchart
b) Data Flow Diagram (DFD)
c) Influence Diagram (ID)
d) Work Flow Diagram (WFD)
e) Process Flow Diagram (PFD)
f) Specification & Description Language Diagram
g) Value Stream Mapping (VSM)
Flowcharts
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10. Flowchart symbols
Direction
Start/stop
Action/Process
Document
Multiple documents
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11. Flowchart symbols
Decision
Manual input
Preparation
Connector
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12. Flowchart symbols
Flow continues in > 1 direction
Junction (convergence point)
Merge symbol
Collate symbol
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13. Flowchart symbols
Sort symbol (step that organizes list of items
into sequence based on a criteria)
Subroutine symbol (indicates sequence of
items that perform specific task embedded
within a larger process)
Loop limit symbol (loop stopping point)
Delay symbol
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14. Flowchart symbols
Database symbol
Internal storage symbol
Display symbol
Process continues Off-page or offline
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15. Types of flowcharts
• Swimlane flowchart: It is a regular flowchart where the shapes of the chart are
organized into separate lanes to visualize stages, employees, departments or
any other set of separated categories
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16. SWIMLANE FLOWCHART
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17. Dataflow Diagram
• Visualizes how data flows through an information system in terms
of inputs and outputs. They are also used to illustrate data
processing.
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18. Influence Diagram
• They are a graphical and mathematical representation of a decision. There are 4
symbols that represent the building blocks of an Influence Diagram: a decision
whether or not to buy a product; a chance variable such as longevity or quality of
product; a general variable such as price; an objective such as Satisfaction.
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19. Work Flow Diagram
• It is used to illustrate the flow of data ad documents through an organization for a
specific product or service. It lets a) understand employee responsibilities, b)
identify potential bottlenecks, c) analyze critical stages, d) improve communication
among employees
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20. Process Flow Diagram
• Also known as Flowsheet, is a flowchart used to illustrate high-level processes in
chemical and process engineering. It focuses on major plant processes and not
show minor details. PFD is the language of Process Chemical Engineers. It is used
in
- Process Piping
- Major Equipment
- Control valves
- Major bypass and recirculation streams
- Operational data
- Process stream names
A process flow diagram that visualizes multiple processes is often called a Block
Flow Diagram or Schematic Flow Diagram.
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21. Process Flow chart/ Block flow diagram
Mixer Reactor Mixer Reactor Reactor
Separator Separator Mixer Reactor Separator
Nat gas
Steam
H2
N2
NH3
H2O
N2
O2
H2, CH4,CO
NH3
H2
N2
CO2
H2O
H2
N2
H2O
CO2
Air
H2, N2
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22. Process flow diagram- advantages
- For better communication and better
understanding
- Effective analysis
- Proper documentation
- Effective coding
- Proper debugging
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23. Specification & Description Language (SDL)
Diagrams
 SDL are used to show detailed structure, communication,
behavior, data, and inheritance for real-time systems.
 They visualize the procedures of state machines in
telecommunications, aviation, automotives, and medical
industries.
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24. Value Stream Mapping (VSM)
 It is a lean manufacturing tool commonly used in
manufacturing, healthcare, software, product
development, logistics, supply chain, and service
industries.
 It is used to analyze the flow of materials and information
required to bring product or service to consumer.
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30. Raw materials
Water
 Used as a reactant in many chemical processes.
 Serves as a solvent
 Utilized in biotech & pharmaceutical industries
 Water may serve as a source of H2, a clean-burning fuel. However,
currently, the technology enabling such conversion is expensive.
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31. Raw materials
Minerals
Minerals are solid inorganic elements or compounds
They are raw materials for Chlor-alkali industry
They are feedstocks for inorganic chemical industries
which produce Silicon chips for computers and
Aluminium for bicycles
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32. Raw materials
Fossil fuels
 Natural gas, crude oil, and coal are important fossil fuels
which are produced by the decay of once-living
organisms.
 They are a source of heat and energy.
 They are raw materials for synthesis of C-based products
such as polymers for plastic soft drink bottles and contact
lenses, fibers for clothing and furnishings, medicines, and
pesticides
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33. Raw materials
Agricultural and forest products
 Source of our food
 Source of fixed quantity of O2 and sometimes N2
 Paper, natural fibers (wool, cotton, natural rubber, and medicines) are
important products
 Biomass as raw materials are popular for producing C-containing
chemicals, thus reducing our reliance on non-renewable fossil fuels.
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