Located in St. Petersburg, Fla., the Pinellas County Resource Recovery Facility (PCRRF) is a refuse-to-energy plant that is operated and maintained by Wheelabrator Pinellas Inc. In 2001, Pinellas County and Wheelabrator Pinellas (WPI) embarked on an ambitious three-year series of modifications designed to dramatically improve the plant’s operating efficiencies. Olson Electric Co. Inc., headquartered in Orlando, was WPI’s electrical contractor of choice for this demanding project.

Originally opened in 1983 at a cost of $243 million, the PCRRF is one of the most successful municipal waste-to-energy facilities in the country. In its lifetime, the plant has converted more than 14.5 million tons of solid waste from Pinellas County residents and businesses into enough clean electric energy to power more than 55,000 homes. In 2000, the Solid Waste Association of North America (SWANA) awarded Pinellas County the Gold Award for Integrated System Excellence, which honors excellence and innovation in the field of solid waste management and in providing environmentally and economically sound management of solid waste.

The replacements

As a prequalified electrical contractor, Olson Electric responded to WPI’s Request for Proposal (RFP) in 2001. Based on the company’s qualifications, its record of previously completed projects, references, sound financial position and staff expertise, Olson Electric was awarded the $2 million electrical contract. Estimates for the complete renovation reach as high as $15 million, and involve a comprehensive overhaul of each of the plant’s three refuse boiler units and replacing all of the steam-generating components.

Although Olson Electric has more than 80 years of experience working in the power plant and industrial process markets installing power instrumentation and control systems, this was its first resource and recovery burner project. “However, our parent company, EEI Holding Co. Inc., located in Springfield, Ill., has significant previous experience with this type of boiler replacement project,” explained Curtis Duffield, Olson president. When Olson learned about the RFP, the company turned to EEI and received a great deal of guidance and assistance in preparing its bid.

Once Olson was awarded the contract, it teamed with WPI’s controls and emission engineering firm, R&B Systems Engineering Inc., Pittsburgh, Pa., to work on the design and layout of the facility’s environmental controls and Local Area Network (LAN) system. “Our staff met with the R&B engineers daily to discuss and design the placement, routing and power requirements of the environmental and LAN systems,” said Duffield. The facility’s automated system is designed to transmit information regarding boiler performance and system temperatures and pressures to facility operators, allowing increased operational efficiencies.

The heat is on

The three boilers at the plant that generate electricity from the steam created from burning solid waste had reached the end of their useful lives. “Wheelabrator was ready to make the investment to replace the boilers and take full advantage of new technology and more efficient and cost-effective control systems,” said Duffield. The project was divided into three phases, and work on retrofitting the first of the three boilers began in August 2001 and ended in January 2002. Work on the second boiler began later that year in September, and was completed in January of this year. Construction on the third unit is scheduled to begin this month and is to be completed by January 2004. In addition, based on the company’s performance on the first phase of the project, Olson has been awarded a contract to work on the rehab of the plant’s turbine controls and water cooling systems, to be completed by January 2004.

Each boiler must be taken offline in turn and retrofit work completed while the other two units continue to operate. “Retrofitting each boiler entails replacing the unit’s heating tube, water wall and stripping the wire from the electrical and instrumentation systems and replacing it with new wire in specialized cable tray and conduit,” said Andy Spencer, senior project manager.

The boiler units’ pneumatic control systems had also reached the end of their useful lives and would have to be replaced. These older systems, Spencer explained, were just not able to efficiently monitor all the parameters of the boilers’ operations as well as the more modern, PLC-based systems. “PLC-based electronic controls offer greater reliability, accuracy, data acquisition and remote control and monitoring functions,” he added.

Once each boiler is retrofitted with new equipment and instrumentation, Olson must run the data transmission wires through 1,700 feet of linear cable tray and conduit to the new distributed control system (DCS) cabinets in the control room. “The LAN system transmits the data acquired from the thousands of sensors and instruments in the boilers and pumps and allows the plant’s operators in the control room to monitor operations and ensure all the systems are maintained properly,” Duffield said. Because of the plant’s new automated PLC-based control system, maintenance personnel no longer have to physically monitor boiler operations and facility operators receive real-time information, which reduces costs and increases operational reliability and safety.

Challenges met

The unique cable tray system presented its own challenges to the Olson team because of the need to custom fit the system to take into account the twists and turns around the facility’s massive boilers and equipment and the high temperatures and other industrial environmental factors present on the site. “The cable tray system had to be carefully designed to take into account the realities of the facility,” recalled Duffield. On a run-by-run basis, Olson Electric project managers and engineers worked with R&B personnel to redesign the system in the field to accommodate existing steam and water pipes, power cable trays and other existing structures.

The project’s time schedule was another challenge for Olson Electric, as there was only a month between the contract award and the scheduled start date for work to begin on the first boiler. “There were substantial penalties for failure to keep to the schedule and long lead times for materials and a steep learning curve,” said Spencer. Olson constructed and maintained a wire-by-wire database to allow them to closely follow the schedule and ensure that every wire was terminated correctly the first time. “The effectiveness of using the database to schedule the work was evidenced by the fact that the wiring errors to date have been near zero.”

The need to work on retrofitting each large, hot, old boiler while the other parts of the system were still in operation made safety another huge challenge on this job, according to Duffield. “During work on the first boiler, a total of 44,060 man hours were performed by electricians and boilermakers, with no lost time due to injuries,” he pointed out. Duffield credits that record to the teamwork between the construction trades on the job and WPI. Daily safety meetings were held with each trade on the site and weekly meetings were held with the owner to ensure that all safety precautions were being taken and that all parties strictly complied with safety regulations and laws.

With new boilers, pumps and a state-of-the-art monitoring and maintenance system in place, WPI can continue to turn waste into clean energy for homes and businesses for decades to come. EC

BREMER, a freelance writer based in Solomons, Md., contributes frequently to ELECTRICAL CONTRACTOR. She can be reached at 410.394.6966 or darbremer@comcast.net