Process Diagrams
What does a Block Flow Diagram (BFD) mainly show?
Major process steps and material flow between units
What happens to pressure drop when pipe length increases (same flow rate)?
Pressure drop increases
Which pump uses a rotating impeller to add energy to liquid?
Centrifugal pump
Which flow meter works using an orifice plate and Bernoulli’s principle?
Orifice meter
Which is the most widely used industrial heat exchanger?
Shell and tube heat exchanger
What information is included in a Process Flow Diagram (PFD)?
Major equipment, flow rates, temperatures, pressures and stream data
Define head loss.
Head loss is the loss of energy of flowing fluid due to friction and disturbances in the pipe.
What is the name of the condition when local pressure falls below vapor pressure in a pump?
Cavitation
Which variable-area flow meter uses a float in a tapered tube?
Rotameter
What is the function of baffles in a shell-and-tube heat exchanger?
To support tubes and increase turbulence, improving heat transfer
What details are shown in a Piping and Instrumentation Diagram (P&ID)?
Piping, valves, instruments, control loops and equipment connections
Which equation is commonly used to calculate frictional pressure loss in pipes?
Darcy–Weisbach equation
Why is NPSH important in centrifugal pump operation?
To prevent cavitation and ensure smooth liquid flow into the pump
Which flow meter has lower permanent pressure loss than an orifice meter?
Venturimeter
What is the first step in the design of a heat exchanger?
Estimation of heat duty
Why are alternative process routes evaluated before finalizing a plant design?
To select the most technically feasible and economically efficient process
Name two causes of pressure loss in pipes.
(1) Pipe friction (major loss)
(2) Fittings, bends, valves (minor losses)
What is pump efficiency?
Pump efficiency is the ratio of output hydraulic power to input mechanical power
What force balances the weight of the float in a rotameter during operation?
Drag force of the fluid
What is the name of the phenomenon where deposits form on heat transfer surfaces and reduce efficiency?
Fouling
Why is a Piping and Instrumentation Diagram (P&ID) more important than a Process Flow Diagram (PFD) for plant operation, maintenance and safety?
Because a P&ID shows detailed piping, valves, instruments, control systems and safety devices needed for operation, troubleshooting and safe plant functioning
Why does increasing pipe diameter reduce pumping cost but increase capital cost?
Increasing pipe diameter reduces pumping costs by decreasing fluid velocity and friction, requiring less energy, but increases capital costs due to higher material and installation expenses.
Why are reciprocating pumps suitable for high-pressure, low-flow applications?
ecause they deliver a fixed volume per cycle and can develop very high discharge pressures
In differential pressure flow meters, flow rate is proportional to what function of pressure difference?
Square root of pressure difference
Which fluid should have a higher velocity for better heat transfer?
The fluid with lower heat transfer coefficient