Process Flow Diagram
· A diagram representing the entire
process sequentially by means of equipment symbols and lines indicating all
equipment and flow directions is called as “Process Flow Diagram ”.
· The Process Engineering Department furnishes the piping analyst
a Process Flow Diagram .
· The Process Flow Diagram shows how the
various items of process equipments are interconnected such as columns , heat
exchanger , blowers and pumps, etc.
· The Process Flow Diagram also indicate
chemical & physical properties such as :-
i) Flow rates, viscosity
ii) Specific gravity, Bulk density
iii) Molecular weights
iv) General flowing materials
v) Expansion
factors
vi) Temperatures
vii) Pressures
· It also shows the process requirements
for fixed points in the process.
Objectives of PFDs :-
· To indicate pictorially the
inter-relationship among various unit operations and process units.
· To provide material balance at all
major steps.
· To provide energy balance in the form
of specific heat, temperature and state of material.(liquid,vapour or gas).
General Considerations while constructing PFDs :-
· It is desirable to show all the
equipments in their relative positions, for eg., pumps and compressors are at
ground level.
· Main process streams are always in
bold, e.g., raw material to finished products.
· The streams are numbered within a
diamond.
· Equipments are numbered generally
based on function or area .
· PFDs are also drawn for utilities ,
effluent treatment process.
· While continuing PFD on other drawing
sheet, one must indicate interconnection between various streams.
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