1. Process Equipment Design and Heuristics - Pumps

2. Types of Process Pumps
Pumps are designed to handle liquids and do not behave well with vapor
Link to Additional Classifications of Positive Displacement and Centrifugal Pumps

3. Centrifugal Pumps
The most common type of pump. Include radial, axial and mixed flow units.
They use one or more impellers which attach to and rotate with the shaft
Usually the best choice for lower viscosity (thin) liquids and high flow rates
Produces head and flow by increasing the velocity of the liquid
Has varying flow depending on the system pressure or head
They generally work within the following ranges:
Flow rate ranges between 5 and 200,000 gpm
Total head (pressure) ranges between 10 and 7,500 ft
Horsepower ranges between and 5,000 hp

4. Centrifugal Pumps
Axial Flow
Radial Flow

5. Positive Displacement Pumps
Second only to centrifugal pumps in terms of their popularity. Operates by alternating of filling a cavity and then displacing a given volume of liquid
Generally used for special applications such as viscous liquids or liquids containing fragile solids
No impellers. Use rotating or reciprocating parts to directly push the liquid in an enclosed movable volume, until enough pressure is built up to move the liquid into the discharge system.
Pump delivers a constant volume of liquid for each cycle against varying discharge. PD’s give a relatively constant flow regardless of the system pressure or head
PD pumps generally work within the following ranges:
Flow rate ranges between .1 and 15,000 gpm
Total head (pressure) ranges between 10 and 100,000 psi
Horsepower ranges between 0.5 and 5,000 hp
Some types can handle millions of SSU viscosity

6. Positive Displacement Pumps
Reciprocating PD
Rotary PD

7. Pump Capacity Heuristics

8. Pump and System Curves pump supplies pressure increase
to increase fluid pressure and to overcome all of these pressure losses

9. NPSH – Net Positive Suction Head
If fluid is too close to vapor pressure at pump inlet, it could flash upon entering pump
NPSH Required (NPSHR): The minimum pressure required at the suction port of the pump to keep the pump from cavitating.
NPSHA is a function of your system and must be calculated, whereas NPSHR is a function of the pump and must be provided by the pump manufacturer.

10. Pump Sizing
The size and costing of a pump is based on its power consumption.
Horsepower = Pressure (psi) x Flow (GPM) /
Note: 1714 is units conversion factor:
1 HP = 33,000 (ft-lbf / min) = 396,000 (in - lbf / min)
231 = 123/7.48 in3 - min/ gal
= 396,000/231 psi – gpm /HP
The power needs to be adjusted by dividing by the pump efficiency (see Table 9.9 above for typical efficiencies)

11. Pump Design Heuristics

12. Aspen Plus Pump Input
Aspen uses a default efficiency if not specified.