Springerville Unit 3 Expansion Project
The 2006 Best Coal-fired Project was awarded to the Springerville Unit 3 Expansion Project, a 400 MW pulverized coal power plant located in Springerville, Ariz. Springerville Unit 3 is the first new coal-fired power plant to be brought on-line in the United States in several years. It is designed to fire Powder River Basin coal as the primary fuel and uses low NOX burners and selective catalytic reduction for NOX control, dry flue gas desulfurization for SO2 control, and a pulse jet baghouse for particulate control. The zero water discharge plant features a wet mechanical-draft cooling tower for plant cooling with makeup water provided from nearby wells. Fly and bottom ash are stored on-site in sealed landfill facilities.
Tri-State Generation and Transmission Association Inc., owner of Springerville, worked with Tucson Electric Power as operator and Bechtel Power Corp. as the engineering, procurement and construction (EPC) contractor during project construction.
The Springerville site is home to two existing 380 MW coal-fired units, also operated by Tucson Electric Power. During the early planning stages of the Unit 3 expansion, project sponsors decided to use best available control technologies so that air emissions from the three unit Springerville site would remain consistent with the permitted levels for the existing two units. To achieve this objective, additional improvements were required on the existing emissions control equipment of Units 1 and 2, including upgrading of existing scrubber systems and installing improved low-NOX burners. This resulted in not only meeting the initial objective, but in reducing the total emissions from the three Springerville units to less than the emissions previously emitted from the two unit facility.
Tri-State authorized Bechtel to proceed with the engineering, procurement and construction in October 2003 and Bechtel guaranteed the project completion within 38 months, but also agreed to target an earlier completion date of September 2006. A few months into the project, however, Tri-State approached Bechtel with a request to accelerate the work so that the plant would be available for operations two months ahead of the previously agreed target schedule. Although construction was well underway, Bechtel agreed to the plant being operational by the end of July 2006.
The project participants knew the remote location of the project—five hours drive from Phoenix—and the robust construction market in the Southwestern United States would make attracting and retaining a craft workforce difficult. The increased labor needs associated with the accelerated schedule amplified the situation, so Bechtel and the labor unions implemented a creative project labor agreement. Under the agreement, union craft workers were able to work side-by-side with non-union craftsmen employed by Bechtel’s subcontractors, which helped broaden the pool of available craft workers. The agreement also included other forward thinking programs, such as the “Helping Hands” program, which greatly improved productivity by permitting craft workers from one union to seamlessly assist craft workers from another without the traditional jurisdictional limitations. Another innovative program, “Helmets to Hardhats,” allowed the project and union to support America’s armed forces by assimilating military veterans coming off active duty directly into the building trades.
The dedication and commitment to safety throughout all phases of the project resulted in achievement of the project goal—zero lost time accidents over the entire course of the 33-month construction period.
By bringing the Springerville Unit 3 Expansion Project on-line five months ahead of schedule, Tri-State is able to meet its customers’ growing needs for efficient, reliable and environmentally responsible electricity generation.
Asheville Power Station
Progress Energy-Carolinas’ Asheville Power Station FGD and SCR Project was awarded the 2006 Best Coal-fired Project Honorable Mention. The Asheville Power Station Units 1 and 2 (392 MW combined) is located at Skyland, N.C., and was required to significantly reduce its airborne emissions to meet the NOX SIP Call, and to comply with the 2002 North Carolina Clean Smokestacks Act. Construction of flue gas desulfurization (FGD) units, or scrubbers, which began in 2003, was one of the most visible changes in Progress Energy’s planned $190 million emissions reduction project at the Asheville Plant. The first scrubber began operating in 2005 and the second in 2006. In addition to the scrubbers, Progress Energy-Carolinas installed a selective catalytic reduction unit (SCR) in 2006, and a second SCR is planned for 2007.
By 2009, when all the improvements are complete, the Asheville Plant will reduce nitrogen oxides (NOX) by 93 percent, compared to 1996 levels and sulfur dioxides (SO2) will be reduced by 93 percent, compared to 2001 emissions. The Asheville Plant will then be among the cleanest coal-burning power plants in the country.
Progress Energy-Carolinas’ set aggressive in-service dates (The timeframe of the detailed design to start-up was approximately 26 months—September 2003 to November 2005.), which were tied to its planned maintenance schedule for the Asheville units.
To meet the schedule dates, reduce the overall project cost and maintain plant operations throughout the FGD installation and installation of the first SCR, close communications between the project team members was critical. Several processes and tools were used to meet the aggressive schedule. An integrated 3-D model with input by Progress Energy-Carolinas, and the project’s other team members, WorleyParsons, Babcock & Wilcox (B&W) and Fluor, proved extremely valuable during the project. The team members also used the Internet, teleconferences and site meetings to review schedules, technical items, concerns and action items. They initiated a request for information (RFI) system where the RFI was numbered, monitored and tracked with the goal of responding within 24 hours of receipt.
The Unit 1 FGD system tie-in was schedule during a two-week outage. To meet this schedule, modifications to the existing balance-of-plant (BOP) systems were made during an earlier six-week turbine outage. The Unit 2 FGD and SCR systems were tied into the existing plant during a six-week turbine outage. The chimney and the FGD absorber towers were constructed at the same time.
To facilitate the construction schedule and minimize construction costs, some of the work was pre-fabricated off-site. The wastewater treatment building was ordered as a pre-fabricated building and all equipment support steel was designed as a free-standing structure internal to the building to avoid interfaces with the pre-fabricated building supplier.
Several unique techniques were used during the project to save both time and money. The team used vertimills and centrifuges instead of ball mills and vacuum filters to save costs and space. They also used tile-lined absorber towers and fiberglass reinforced plastic (FRP) absorber outlet and chimney flues to save on alloy material use. The absorber tower outlet ducts are supported by the absorber tower and chimney and not by steal from grade. In addition, modularized ductwork was used in the SCR reactor and ash dropout chamber.
The team completed all the project work on time and with zero lost time accidents while meeting their SO2 and NOX reduction goals.