Hydraulic Simulation of Cooling System

Scope of Work – AFT Fathom Hydraulic Model
Cooling Water System – Option 1 (Single High Pressure Pump, Two Process Trains)
1. Overview and Objective
The purpose of this work is to develop a steady state hydraulic simulation of a cooling water distribution system using AFT Fathom.
The system to be modelled is a single fixed speed, high pressure cooling water pump supplying two parallel process trains. The model will be used to verify flow distribution, pressure levels at each cooling user, and the use of local pressure inducing devices to meet equipment pressure requirements.
This work is limited to hydraulic modelling only; no thermal or control system modelling is required.
________________________________________
2. System Description
The cooling water system comprises:
• A single high pressure pump operating at fixed speed
• A common supply and return header
• Two identical process trains operating simultaneously
• Individual branch connections to each cooling consumer
• Needle valves used to induce pressure loss and balance flows
Only the Option 1 configuration (single high pressure loop) is to be modelled.
________________________________________
3. Cooling Consumers and Design Flows
The AFT Fathom model shall represent the following cooling consumers:
Per Process Train
• Cathodes:
o 2 per system total
o Flow: 13 LPM each
• Anodes:
o 2 per system total
o Flow: 13 LPM each
• Process Heat Exchangers:
o 2 per system total
o Flow: 40 LPM each
Additional Cooling User
• Screw Conveyor Cooling Circuit:
o 1 off (common)
o Flow: 10 LPM
Total Cooling Water Flow:
142 LPM
________________________________________
4. Pressure Requirements and Flow Control
• Each cooling consumer (Cathode, Anode, Heat Exchanger, Screw Conveyor) requires:
o Minimum inlet pressure of 8 barg
• The system pump will deliver a higher discharge pressure, with pressure losses introduced locally
• Needle valves shall be modelled in the appropriate branches to:
o Achieve the required 8 barg at each consumer
o Balance flows between parallel users
The intent is to demonstrate that correct flows and pressures can be achieved through system resistance rather than pump speed control.
________________________________________
5. Modelling Requirements (AFT Fathom)
The model shall include:
• Explicit representation of:
o Pump
o Supply and return headers
o Branch piping to each cooling user
o Needle valves (or equivalent pressure loss elements)
• Pipework to be modelled using data provided by the client, including:
o Pipe diameters
o Pipe lengths
o Fittings / minor losses where shown
o Known differential pressures where specified
• Cooling consumers may be modelled as:
o Fixed flow demands with pressure constraints, or
o Equivalent resistance elements
(provided the modelling approach is clearly documented)
One main steady state operating case is required:
• Both process trains in operation
• All cooling users active
• Pump at fixed speed
• All equipment meeting flow and pressure requirements
________________________________________
6. Information to Be Provided
The following will be issued by the client prior to commencement:
• Cooling water distribution PFD
• Piping isometric showing:
o Pipe sizes
o Pipe lengths
o Elevations (if any)
o Stated differential pressures or design losses
• Confirmation of cooling water properties (water at operating conditions)
The original design option study / design note will not be provided.
________________________________________
7. Deliverables
The following shall be provided as part of the work:
1. AFT Fathom Native Model File
o Fully editable *.aft file
2. Fathom Flowsheet
o Clear graphical model showing all equipment, branches, and flow paths
3. Model Report
o Summary of assumptions
o Flow and pressure results at:
 Pump discharge
 Headers
 Inlet of each cooling consumer
o Pressure drop across each needle valve
o Confirmation that all users meet 8 barg minimum pressure
4. Brief Explanatory Notes
o Description of modelling approach
o Any modelling limitations or observations
________________________________________
8. Review and Payment Milestones
Work will be reviewed in two stages:
• 80% payment milestone:
o Submission of:
 AFT Fathom native file
 Flowsheet
 Model report
o Documents issued for technical review and checking
• 20% payment milestone:
o Paid after:
 Review comments are addressed
 Final revised model and report are submitted
________________________________________
9. Exclusions
Unless specifically agreed otherwise, the following are outside the scope:
• Transient or surge analysis
• Thermal or heat transfer modelling
• Pump mechanical design, NPSH assessment, or vendor selection
• Development of operating or control philosophies
• Detailed valve sizing beyond hydraulic pressure loss representation