Cooling Water

Sentinel for Cooling Water

Using patented technology to model actual process exchanger skin temperatures and velocities, Sentinel is the first performance monitoring technology that can provide a visual, real time picture of the cooling water treatment results. This provides an accurate method of predicting reliability and insures optimum production.  This is 21st Century cooling water performance monitoring. In today’s uncertain and volatile market, industry cannot afford any additional level of uncertainty.  Protect your plant from unexpected production loss and equipment failure.  Sentinel is designed to operate at skin temperature, velocity and heat flux of the critical bundles in the plant while monitoring the actual cooling process. Through the implementation of Sentinel, we can offer industry a method of measuring and reporting the actual corrosion rate occurring within the process equipment at actual operating conditions. Field data proves and illustrates how significant the deviation between traditional corrosion rate measurement and actual conditions can be.  Knowing corrosion rates at operating conditions is critical when evaluating treatment methods and operational or maintenance planning.  Run time between turn arounds is becoming longer which makes reliability of cooling water exchangers even more critical.  It is imperative to planning, efficiency and operational reliability to abandon antiquated testing methods and embrace new technology for corrosion monitoring and begin taking into account the actual corrosion rates instead of much lower estimates provided by our traditional methods.

How does Sentinel Work

The “Sentinel for Cooling Water” contains two annular exchangers (one tube bundle) consisting of a 0.5 inch (12.7mm) OD tube inserted in a 1 inch (25.4mm) clear polycarbonate shell. The 0.5 inch exchanger tubes are pre-weighed prior to exposure to the cooling water, similar to a corrosion coupon. The exposed surface consists of 18” on each tube. Cooling water flows through the exchanger on the outside the 0.5 inch tube specimen and process water is inside the 0.5 inch tube simulating the process and providing the required heat to duplicate the actual and simulated skin temperatures. The independent operation of this skid with its own process allows inspection of exchanger results at any time regardless of the plant’s turnaround schedule.  Adjustments of chemical treatment programs and controls can be made to optimize system results immediately following the identification of poor results in the Sentinel, avoiding loss of actual heat transfer in the plant or exchanger failure due to unacceptable corrosion.  Any metallurgy specific to plant equipment can be used for the material of construction of the 0.5 inch inner tube specimen.  Pre-weighing of the heat transfer tube allows for determination of scale accumulation (dirty weight) as well as actual metal loss due to corrosion (cleaned weight) at the end of the exposure period.

How has Sentinel Been Used

One of our first “Plant Beta Sites” was experiencing mineral deposition and under-deposit pitting corrosion in excess of 0.30” deep. Over a 2-year period results have been improved significantly and a number of additional uses for this tool have been identified:

• Mineral deposition eliminated
• Localized pit depths reduced 98.7% (current maximum pit 0.004”).
• Evidence of effective system passivation following a turnaround.
• Visual impact of microbiological excursions on heat transfer surfaces following the loss of oxidant feed.
• As an online visual tool to determine the effectiveness of system cleanup following a bacteria excursion and a method to clearly identify how long a clean-up protocol should be run.
• Sentinel was used as an operations training tool for online observations of cooling water performance, demonstrating to operators the importance of control and selected chemistry.

An Interview With Brian Bloxam