Case Study: Cooling Water Modeling
2020 / CASE STUDY
How Hydrus Works Caught a Critical Flaw Early in the Design Cycle
Introduction
As part of a unit expansion, a Gulf Coast refinery was planning to incorporate additional heat exchangers into an existing cooling water circuit to serve new process equipment.
The site planned to utilize a cooling water circuit from a neighboring unit and was unsure what impacts the new exchangers would have on existing users. That’s when the project team reached out to Hydrus for help.
Hydrus deployed a thorough, data-driven approach to develop an accurate hydraulic simulation model to quantify the cooling water system’s current conditions and simulate future performance.
As a particularly complicated cooling water circuit, the system exhibited multiple two-pass sub-circuits, four header jumpers to enable a degree of flow control, and a looped header system.
To ensure model accuracy, a comprehensive onsite flow, pressure, and temperature survey was executed to construct a dataset to calibrate the model against. This dataset, combined with operational data, online instrumentation, and field observations allowed Hydrus to intelligently calibrate the model within 4% of measured conditions.
110 |
PRESSURE DATA POINTS COLLECTED |
115 |
TEMPERATURE DATA POINTS COLLECTED |
60 |
FLOW DATA POINTS COLLECTED |
4% |
AVERAGE MODEL ACCURACY TO MEASURED DATA POINTS |
Once calibrated, Hydrus engaged site personnel to evaluate the project’s proposed changes to the cooling water circuit. Multiple scenarios quantified the individual impacts to each exchanger currently on the circuit in a multitude of conditions, allowing project engineers peace of mind that their project would not negatively impact existing unit operations.
Assumptions Almost Led to a Bottleneck on Day One
Hydrus’ routine efforts yielded a key benefit not expected by the project team; identification of a critical hydraulic bottleneck in the rule-of-thumb design proposed by the incumbent process design firm. This key detail would have throttled flow to the new exchangers on day one of operation, limiting exchanger performance and shortening bundle life. Hydrus’ unique approach allowed the team to catch an erroneous assumption by uncovering an otherwise undetectable condition that would have hindered project results.
Better Tools. Better Decisions.
GRANULAR RESULTS
Normally scattered across drawings, datasheets, online instrumentation, and engineering roles, the tools and data developed by Hydrus offered the project team a wealth of data and information about their utility system in a tidy, user-friendly package. This enabled plant engineers to have more detail at their fingertips for the project than ever before.
WHEN RULES OF THUMB AREN’T GOOD ENOUGH
Process design firms often underestimate the plant-wide impacts overstressed utilities can have, as it’s crucial to stay on top of the critical systems that support the entire plant. This project demonstrated that Hydrus’ approach is a key element in maintaining the critical infrastructure that supports the site.
OPTIMIZATION OPPORTUNITIES
“Hydrus got more cooling water to our money makers with valves that had been there all along.”
Hydrus’ data-driven analysis approach revealed a no-cost flow path optimization option that the unit team was previously unaware of. The option allowed the unit to change jumper valve configurations to improve flow rates to key exchangers, netting improved performance, better exit temperatures, increased tube velocities, and extended exchanger life and reliability.
Hydrus caught a critical design mistake early in the design cycle, ensured a unit expansion had no adverse impacts on existing utility operations, and uncovered no-cost optimization opportunities that the plant was unaware of.
THE HYDRUS APPROACH
MINIMIZE ASSUMPTIONS
Eliminate the guesswork with measured, real-world data to push your project out of the theoretical
DO THE HOMEWORK
Leverage sound, data-driven design analyses and decision making to ensure any project’s success
EXCEED PROJECT GOALS
Uncover opportunities not typically revealed through conventional engineering approaches