Best Practices Awards go to Waterside Power, Ripon Cogen, Terry Bundy, Rokeby

The three LM aero facilities among the nearly three-dozen plants selected by a panel of industry judges to receive the CCJ’s 2015 Best Practices Awards were recognized by their peers at the Western Turbine Users Inc’s 25th anniversary meeting. The presentations were made during the group’s Tuesday awards luncheon, March 17, by Editor Bob Schwieger. Summaries of the plants’ accomplishments follow:

Waterside Power, an emergency oil-fired peaking plant serving ISO-New England, received a Best of the Best award for its HMI upgrade, enabling automatic starts of three TM2500s and dramatically improving reliability. Automation of the fuel forwarding system was part of the improvement effort. Proven project results include the following:

      • Staff reduced from five to three employees, including the plant manager.

      • Time to go from notification to start to the desired dispatch point was reduced to 10 minutes.

      • Between the time the HMI automation project was completed and the awards entry was prepared at the end of 2014, Waterside had responded to 29 fast-start emergency dispatches without a failure and made 40 successful starts without an operator error or a trip of any kind—both plant records.

Ripon O&M personnel were challenged to keep their LM5000-powered cogeneration facility operating reliably given the unpredictable nature of plant’s 25-yr-old WDPF control system. Multiple fail-safes were hard-coded into the DCS, so even small deviations in process variables—such as temperature fluctuations—could trip the unit. Re-starting of the gas turbine and critical subsystems—including the chiller and water treatment facilities—took about an hour.

A new contract with the California Independent System Operator focused on fast starts and flexible ramping. Reliability concerns, plus a lack of local support (repairs, maintenance) for the antiquated DCS, dictated the migration to a “non-proprietary” PLC-based control system with state-of-the-art functionality. Examples of the last include embedded time synchronization, rack-based historian, sequence-of-events capture, integrated condition monitoring, intelligent motor control, etc.

Project benefits include the following:

      • Shutdowns and nuisance fail-safes are down nearly 90%. By eliminating unplanned shutdowns, the plant typically starts up only once daily now, keeping emissions well within permit limits.

      • Other regulatory issues associated with unpredictable performance—the plant operates under permits from a dozen different regulatory bodies—have been mitigated by the new automatic start capability and ability to monitor operating conditions in real time.

      • Re-start time has been reduced by 15 minutes.

      • The transition to a non-proprietary network simplifies hiring. New personnel do not require specialized expertise to operate the plant and troubleshoot controls issues.

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Lincoln Electric System’s Terry Bundy Generating Station is equipped with three LM6000s, two incorporated in a combined cycle; the third is a simple-cycle peaker. The plant’s main source of water is treated effluent from one of the Nebraska city’s wastewater treatment facilities two miles away. Chemistry in the 3-million-gal storage tank at Bundy requires round-the-clock monitoring and periodic adjustment given the cycling nature of the 2 × 1 power block. The wet cooling tower is the largest water consumer onsite.

The original process for bio-growth control in the storage tank had its limitations. Chlorine addition was by carrying containers of the biocide to the top of the tank and pouring it through a hatch. This was not in keeping with today’s safety culture; plus, mixing of the chemical with tank inventory was not thorough and the release of chlorine gas in the upper reaches of the tank contributed to the corrosion of roof structural supports.

Terry Bundy personnel resolved all three issues by replacing the original 2-in.-diam recirculation line between the storage tank and the cooling-tower sump with a 6-in. pipe equipped with chemical injection ports and arranged for automated delivery of chlorine to the system. In addition, the new recirc line was designed with a flow-distribution nozzle to enhance tank circulation and mixing.

Lincoln Electric’s Rokeby Generating Station, which also received an award, has three chiller-equipped simple-cycle gas turbines though not aeros, but the project is very applicable to the LM fleet. The air-inlet chillers are supplied by two thermal-energy storage systems (total of 4 million gal) equipped with 2030 tons of ammonia-system ice-making equipment. During the site’s last risk-management program review, the potential for a catastrophic ammonia release was identified as a major concern. Reason: Plant was in a rural setting when it was built a decade ago; today there are residential developments on three sides.

Plant installed and demonstrated the effectiveness of detection and suppression systems to mitigate the impact of an unlikely ammonia release. The suppression system, designed to NFPA 15, consists of multiple spray nozzles configured on water distribution lines surrounding the 2800-gal ammonia receiver and condenser—considered the most vulnerable system components. Spray density is 0.25 gpm/ft2. The site’s fire protection system provides spray water at the pressure and flow required.

Detectors are installed both in the immediate vicinity of ammonia-system equipment and at the plant perimeter. The latter are solar-powered and have wireless CIP-compliant communication links to the detection system controller. Sensors can output alarms for multiple concentrations of ammonia. Thought is being given to automatic actuation of the spray system based on multiple sensor indications of a leak because the site is not manned 24/7.

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