Orange County (FL) recently completed substantial upgrades to one of its main water supply facilities in the Orlando area. This project originated in 2004, and I was glad to have the opportunity to work with the engineering team responsible for the design of the fuel supply system for the emergency generators.
This is a critical facility and power continuity was a key design criteria for the team. With this in mind, the fuel system for the generators needed to be highly reliable, with special attention given to having redundant systems for all major components deemed critical to the operation of the emergency generators. Here are some of the highlights for the scope of work related to the fuel supply system:
- The facility already had two existing bulk fuel storage tanks. The existing tanks were refurbished and supplemented by the addition of two new “protected” tanks, for a total of 40,000 gallons of fuel storage on site.
- The bulk fuel storage tanks were tied into a common fuel supply manifold, equipped with electrically-operated valves with integral position indicators to monitor their operation. A Simplex control panel operates these valves to allow selection of any one tank, for supply of fuel to the generator day tanks. The automated system can monitor each tank and is able to isolate a tank that is contaminated, or in need of maintenance.
- Tank filling operations are accomplished via a multi-tank Simplex Automatic Fuel Port, compliant with current FDEP requirements for overfill prevention and spill containment. With this system, a fuel delivery company connects their tank truck to a single point of connection and, using the controls on the Simplex Fuel Port, the operator can “direct” fuel to the desired tank. The filling operation is monitored and the operator is alerted when a tank is approaching its full level. This system minimizes the amount of time it takes to fill the tanks, and also reduces the likelihood of a spill while connecting and disconnecting from the delivery vehicle.
- Fuel transfer between the fuel farm and the emergency generator building was a top item in the fuel system design. To accomplish the reliability goals, the project was designed with two fuel transfer stations, each including duplex pumps, configured for lead/lag operation should one pump fail.
- An automated fuel filtration system was also installed, to maintain the quality of the large fuel volume stored in the tanks.
- All controls were designed to tie into the County’s SCADA system via fiber-optic communications, so facility personnel could monitor normal and abnormal events remotely and in real-time.
- Redundant secondary containment fuel transfer piping systems were designed to run from the fuel farm to the emergency generator building. Each pipe system was designed to be monitored for leaks, in accordance with FDEP requirements. In the event of a pipe failure, the redundant pipe system can be used while repairs are conducted.
- At the generator building, Simplex day tanks are located next to each of the three emergency generators. Each day tank has a capacity of 200 gallons, and each is configured with PLC-based controls and GUI displays to provide clear indication of all normal and abnormal conditions.
- Whenever a day tank requires refilling, the automatic controls communicate with a Simplex “Tank Selection” control panel which, in turn, selects a bulk storage tank and signals the transfer pump to operate.
- All mission-critical Simplex components (transfer pumps, day tanks, etc) were specified to have stainless steel enclosures and stainless steel internal piping, to provide extended longevity in Florida’s environment.
Here’s an excerpt about this facility from the County’s “Utilities in Focus” – Fall 2014:
The Eastern Regional Water Supply Facility (ERWSF) is a 50 million-gallon per-day water supply facility that serves the 284 square miles of the East Water Service Area (EWSA) in Orange County. The ERWSF is the only water
supply facility that serves the 84,506 customer connections, so it is critical this facility stays operational and up-to-date.
The ERWSF was originally constructed in 1998 and is in need of certain improvements. The design of the ERWSF Improvements Phase IIIA project was completed and advertised for bid. The construction contract was awarded to
Garney Construction, Inc., at a cost of $12,950,000 with an expected date of completion in April 2016. Construction began in August 2014.
This project will improve the reliability of the existing standby power generation system and various unit operations and processes throughout the facility. The work consists of a new generator building; three new 2,000 kW generator sets with associated fuel storage and paralleling gear; new well houses at four existing potable water supply wells; stormwater pond improvements; new chemical process building for new fluoride and carbon dioxide storage and feed systems; yard piping improvements to provide greater system reliability; new dedicated air quality control blowdown lift station; and site entrance improvements that include a new guard shack and separate employee and visitors lanes.
All of these improvements must be done while keeping the facility completely operational 24 hours a day, as it is a regional facility with limited backup in the event of an outage.