Transcript Exchangers - Martin Ryan Consulting

Training Series:
Using Aspen Technology Economic Evaluation Suite
Specifying Pumps.
Prepared by Martin Ryan, 2013
Centrifugal Pumps: images
Centrifugal Pumps:
The API 610 pump model is the most commonly
used for process pumps, design is for 20 year
service life, 3 years uninterrupted service, heavy
duty casing, costs more than ANSI.
Over 300HP the system adds TEWAC motor,
cooling lines, temperature control loop.
Guidelines for conceptual estimates:
• Use ANSI pumps for non-critical service
• Use API 610 pumps for hydrocarbon services
• Use single seal for water service
• Use double mechanical seal for hydrocarbons
• Specify seal plans 11/52 with double mechanical seal
• Allow the system to size motors with ~70% efficiency
• If head not given see below
• Design pressure affects casing weight & cost
• Lower speed (e.g. 1800 rpm) pumps cost more
See Icarus Reference, Chapter 7 Pumps.
Often the equipment list will provide differential pressure instead of head:
Head (m) = Differential Pressure (kpa) * 0.101 / SG
Head (feet) = Differential Pressure (psi) * 2.31 / SG
Centrifugal Pumps: specific cases
ANSI pumps follow the ASME B73-1991 pump
spec. They are dimensionally interchangeable,
may be horizontal or vertical. They are available in
a wide variety of materials, are single stage
overhung impeller type, cost is typically less than
API 610.
Axial flow pumps operate at much lower pressures,
low head, and high flow rates.
Canned motor pumps avoid seal failures.
For larger pumps which exceed the limits on other
models, the CENTRIF multi-stage can be used.
Cast iron pumps, low cost, general service.
For sump pumps (immersed with no inlet line) use
the vertical turbine pump model.
In-line pumps (generally smaller sizes <40HP) are mounted in the
piping line, eliminating the foundation or reducing it to a small block.
Gear/Positive Displacement Pumps:
specific cases
Gear pumps are used for pumping viscous liquids
such as resins.
Reciprocating positive displacement pumps use piston(s),
plunger(s) or membrane(s) to move fluids.
Use the diaphragm pump model for chemical dosing
applications or metering, typically <25gpm. Seals are not
exposed to the liquid being pumped.
Triplex plunger pumps are versatile pumps, used for
injection (e.g. fracking) and circulating drilling mud.
Centrifugal pumps, default P&ID
Three piping valves, one strainer, one flow control valve, one pressure gauge, per item.
Pump data input:
The API materials available.
Variable Frequency Drive available – cost is
output in the electrical account.
Use double mechanical seal for hydrocarbons
If this is an installed spare
pump, use the SPARE
keyword to adjust P&ID
Pump data input for spare pump:
Under the Options menu on the spare pump,
choose the “Mat’l/Man-hours % Adj.” form.
Under Installation option choose SPAR
The SPAR keyword will reduce the
pipe, assuming the other pump
has a manifold, and will remove
the control valve loop.