Objective - ABB 800xA Operation

Objective

Objective
The objective is to detect drastic drops in heat exchanger efficiency, rather than
minute changes. This is accomplished by taking baseline measurements of the
critical readable process variables around the heat exchanger and noting any trends
indicative of declining performance. One of the major factors affecting heat transfer
efficiency is fouling. For each occurrence of the input variable which is a reasonable
match for the baseline sets, heat exchanger performance can be compared to the
baseline.
The basic approach of the Heat Exchanger Asset Monitor is proprietary modeling
and analysis, along with an understanding of the measurable boundary conditions.
This approach creates a basic Asset Monitor that alerts maintenance personnel of
significant changes in heat exchanger Key Performance Indicators (KPI), such as:
Efficiency:
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Instrumentation Errors:
•
In addtion to the above, HXAM-ST supports the following:
Process Errors:
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•
•
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Fouling, as indicated by:
– Delta T profiles drifting at reference Hot and Cold flows.
– Delta P across the exchanger increasing at reference (constant) flow for
either Hot or Cold leg.
– Low Flow or Low Delta T readings for either leg.
– Significant changes in operating point which affect efficiency or heat-duty.
Delta T, Delta P, Delta F, or Heat Duty Error resulting in
undefined/unreasonable values.
Temperature Crossover.
Low Shell-side Flow.
Low Heat Transfer.
High/Low Tube Velocity.
Low Limiting Approach Temperature.
Section 9 Heat Exchanger Asset Monitor (HXAM)
3BUA000150-600