How can an automatic flow controller streamline busy startup times? See how one utility eliminated redundant tasks and reduced man hours with our newest flow controller. This project was originally presented by Jason Thomas at the 37th Annual Electric Utility Chemistry Workshop, held June 6-8 in Champaign, Illinois.
A power plant in Florida frequently cycles, requiring plant personnel to manually adjust valves during already busy startup times. Plant operators wanted to eliminate these redundant tasks to reduce the burden on staff and more easily maintain EPRI-recommended sample velocity.
Automating Sample Flow
The Sentry® AutoVREL Flow Controller allowed operators to automate the sample flow of new or existing sample panels through a simple device using feedback from an attached flow sensor. With the AutoVREL “smart” function, the operator simply sets the desired sample flow and the system automatically adjusts to changes in the sample pressure.
The AutoVREL Flow Controller was installed on a trial basis on an existing Sentry Sample & Conditioning Panel by bypassing the installed manual VREL, TSV (Thermal Shutoff Valve) and tubed the sample line in to the Beta Unit, which housed these same components along with the PLC, Flow Sensor, AutoVREL controller and Motor attached to the valve.
Sentry AutoVREL design
The Result: Eliminating At Least Two Man Hours Per Cycle
With the Sentry AutoVREL Flow Controller, the power plant eliminated a minimum of two man hours per cycle, per unit (of similar construction).
The AutoVREL unit responded to changes in drum pressure during cycling, startup and shutdown conditions. We were able to control actual sample flow within 10% of set point consistently over the duration of the beta test.
Plant staff reported favorable impressions across the board, including less manpower to walk down panels making adjustments to valves during already busy startup times. Personnel also reported they obtained better chemistry by maintaining constant flow rates and therefore more representative samples. They also realized increased stability in online steam cycle chemistry analyzer readings overall, and the constant VREL movements during routine cycling helped clean out debris in the valves.
