Solution Provided | Process Review
Discipline | Process, Mechanical, Control
An Alumina Refinery was set to decommission their gas fired Cogeneration facility, which would reduce the supply capacity for low pressure and medium pressure steam for use in various facilities across the refinery. This represented a potential risk to the refinery production plan as the steam supply limitations could reduce the refinery throughput. With existing operating issues that include high variability in steam demand, deteriorated pressure and quality at point of use, and control difficulties for some users, the client engaged Carnac to perform a thermal and hydraulic review to:
- Assess steam distribution,
- Benchmark steam consumption performance, and
- Determine potential conservation opportunities.
Carnac developed a hydraulic model for each of the low pressure and medium pressure steam systems using Piping Systems Fluid Flow, which were based on current 'as built' configuration drawings and were verified against actual process operating data. Following verification of the model, a hydraulic review of the system was performed to identify which nodes did not meet the required supply criteria. For non-performing nodes, potential remedial strategies were recommended. Carnac identified areas where:
- Supply pressures were higher than normal, a rectification of which would result in energy savings;
- Control valves were observed to open beyond the outside typical controllable range;
- Facilities demanding steam were underperforming;
- Steam flow velocities were above pipe specifications; and
- Sudden changes in steam flow would affect facility performance.