Ray Hardee is a principal founder of Engineered Software, creators of PIPE-FLO and PUMP-FLO software. At Engineered Software, he helped develop two training courses and teaches these courses internationally. He may be reached at email@example.com.
Not rebalancing the flow rates after changes to the cooling water system was the first problem. The second was that operators increased the flow rate through the plant loads without understanding how changing one flow rate affects the flow rate in the other circuits.
The final problem was that the only option the plant considered was adding a third operating pump and a backup pump. Rebalancing the system solved the problem at hand, without the need to purchase and install a fourth pump that would take four months to install, leaving the plant without a backup cooling water pump.
By developing a model of the cooling water system’s operation, the engineer could understand how the system was designed to operate. He was able to determine the source of the problem—all throttle valves open—by comparing the calculated results to the physical piping system.
Validating the piping system model with the operation of the physical system allowed him to try alternative solutions to the problem. By simulating the system with the balanced flow rate set in the loads and two pumps operating, he was able to calculate the throttle valve position needed to balance the system.
In next month’s column, with the aid of the piping system model, we will see how the plant was able to reduce system operation costs while increasing system capacity.
To follow the process described in this example, visit www.pumpsandsystems.com/large-system-optimization.