BFD - Block Flow Diagram - Example

A block diagram visualize the principal parts of a system by blocks connected with lines. A block diagrams is typically used for higher level, less detailed descriptions to clarify the overall concept.

The blocks or rectangles in a diagram represents typically a unit operation and the lines represents typically process flow streams. Process flow streams may be mixtures of liquids, gases and solids flowing in pipes or ducts, or solids being carried on a conveyor belt.

• unit operations such as mixers, separators, reactors, distillation columns and heat exchangers are usually denoted by a simple block or rectangle
• groups of unit operations may be noted by a single block or rectangle
• process flow streams flowing into and out of the blocks are represented by straight lines
• the direction of flow of each of the process flow streams must be clearly indicated by arrows
• flow streams should be numbered sequentially in a logical order
• unit operations should be labeled
• the diagram should be arranged so that process material flows from left to right with upstream units on the left and downstream units on the right

Temperature ^oC
K
^oF

Length m
km
in
ft
yards
miles
naut miles

Area m²
km²
in²
ft²
miles²
acres

Volume m³
liters
in³
ft³
us gal

Weight kg_f
N
lbf

Velocity m/s
km/h
ft/min
ft/s
mph
knots

Pressure Pa
bar
mm H₂O
kg/cm²
psi
inches H₂O

Flow m³/s
m³/h
US gpm
cfm