By Lindsay Morris, Associate Editor
At a gala banquet at POWER-GEN International in Orlando, Fla., on December 14, Power Engineering magazine’s editors recognized the 2010 Projects of the Year Award finalists and announced four winners. This year’s Projects of the Year Award winners and honorable mentions represented facilities and/or technology that signified excellence in four categories: coal-fired, gas-fired, nuclear and renewable/sustainable energy.
Best Coal-fired Project
Great River Energy’s DryFining process
After 13 years of research and development in an effort to find a more affordable way to control emissions, the Coal Creek Station, a 1,200 MW plant near Underwood, N.D., implemented its DryFining process in December 2009. This 2010 best coal-fired project is operated by Great River Energy, which developed the technology in-house to improve fuel quality by simultaneously drying and refining low-rank coal. The DryFining technology integrates waste heat in place of primary fuel to dry lignite without volatization. The project is also unique in its continuous segregation of particles bearing the highest concentrations of pyritic sulfur and mercury and the complete integration within the existing plant.
|Great River Energy’s Coal Creek Station|
The concept for the DryFining technology stems back to 1997 when Great River Energy plant engineers began brainstorming ideas for efficiency improvement. The obvious resolution was to add on to existing emissions control equipment, which would incur high capital and operating expense.
Instead, engineers decided to explore ways to improve fuel quality by drying the lignite to improve efficiency and mechanically remove some of the impurities prior to combustion. The pilot-scale equipment demonstrated that lignite particles habitually separated by density during the drying process. The higher density compounds—those containing higher concentrations of sulfur and mercury—could be removed from the coal steam prior to combustion.
The DryFining system is providing financial and operational advantages to the Coal Creek Station in comparison to alternative emissions control equipment. DryFining has a lower initial cost of installation and reduces expenses by more than $20 million annually in fuel, auxiliary power and other operations and maintenance costs. The alternative compliance equipment would have cost $91 million more upfront and increased O&M expenses by more than $24 million annually.
In terms of emissions control, DryFining reduces the volume of flue gas by 17 percent by driving off and diverting water vapor prior to combustion, improving the efficiency of fans, motors and existing emissions control equipment while reducing station service. The process also separates fuel particles by density. This means that higher density compounds containing more sulfur and mercury are sorted out and returned to the mine before undergoing the combustion process. Consequently, sulfur dioxide and mercury have been reduced by more than 40 percent, nitrogen oxide has been reduced by more than 20 percent and carbon dioxide has been reduced by more than 4 percent.
The DryFining process has improved the overall performance of the Coal Creek Station by almost 4 percent. Great River Energy has been awarded two patents on the process with four patents pending and has partnered with WorleyParsons to commercialize licensing the DryFining technology worldwide.
W.H. Sammis air quality control project
The W.H. Sammis Plant on the Ohio River in Stratton, Ohio, is a 2,200 MW facility. Owner/operator First Energy Generation Corp., a unit of FirstEnergy Corp., began a $1.8 billion project in 2005 to retrofit the plant’s air emissions controls. Bechtel Power Corp. served as the engineering, design and procurement contractor for the majority of the project. Babcock & Wilcox Power Generation Group, with engineering support from Stantec Consulting Services Inc., designed and installed two key components of the project: scrubbers to remove sulfur dioxide and selective catalytic reduction (SCR) equipment to remove nitrogen oxides.
This project encountered limited space for installing the new equipment. The site’s location near the Ohio River, the Cumberland Lock and Dam, State Highway Route 7, the Village of Stratton and the Norfolk Southern Railroad also presented logistical restraints. Adding to the challenges was a concrete deck more three football fields in length that was built in the 1980s over the state highway for a previous retrofit of fly ash controls.
Solutions to these challenges included designing and installing the new SCRs inside and under the roof of the existing boiler structures. To minimize structural loading of existing steel and foundations, demolition of previously abandoned precipitators was necessary. The engineering team also changed the flue gas discharge from the west side to the east side for four baghouses to allow the flue gas duct to route over the state highway and along the Ohio River. In addition, erection hours and multiple handling were minimized by modularizing the three scrubbers (and 8,900 tons of new duct work) into 337 prefabricated and pre-insulated modules delivered to the construction site just in time for installation.
Despite a number of roadblocks, the emissions control project for the Sammis Plant was completed early, without any forced outages. Over 2,200 construction positions were created over the course of the project. The new Sammis Plant system will reduce sulfur dioxide emissions by more than 95 percent and nitrogen oxides emissions by more than 90 percent.
Oak Grove power plant project
The Oak Grove Project is a story of the revival and union of two half-started plants. In the mid-1970s, utility TXU approved construction of two lignite-fired power plants, called Forest Grove and Twin Oaks. However, the need for new generation eaed and the projects were deferred. Some of the equipment for each site had already been delivered to the job sites. At the Twin Oaks plant, some of the plant’s concrete infrastructure had been installed and the boiler structural steel had been started.
In the mid-2000s, Luminant revisited the two plants and selected the existing Twin Oaks site, some 100 miles northwest of Houston, to leverage existing site work and infrastructure. The project was given a hybrid of the two original project names: Oak Grove. The new facility is comprised of material from both original plants. Fluor, the project’s engineering, procurement and construction (EPC) company, completed the plant in 35 months.
The plant now delivers 1,640 MW of power. Oak Grove is one of the nation’s first 100 percent lignite-fired plants with selective catalytic reduction (SCR) for nitrogen oxide reduction and activated carbon sorbent injection for mercury control. The units are designed to have lower emission rates than any existing lignite plant and rates at least 70 percent lower than the national coal plant average.
An aggressive front-end schedule required the team to conduct engineering at the same time as supporting the client’s air permit approval. The EPC contract required Fluor to assume responsibility for all of the mothballed parts, redesign the plant as necessary to meet current-day requirements, and wrap a custom set of guarantees and warranties around the plant. This included refurbishing, upgrading, bringing back online 30-year-old steam generators, steam turbines and other major equipment and integrating them with new equipment and control technology.
Unit 1 was built in 30 months and Unit 2 in 35 months; on time and under budget. At peak, the project employed 2,400 site workers; almost 200 full-time, permanent local jobs have been implemented at the facility. As part of the recruitment effort, the Oak Grove site worked with the U.S. Department of Labor through its Job Corps Graduate program, employing 35 Job Corps personnel worked in various aspects of the project.
Best Gas-fired Project
Sendai thermal power station replacement projects
Tohoku-Electric Power Co. won the Project of the Year for best gas-fired project with its 446 MW Sendai No. 4 combined-cycle plant. This plant, in Shichigahama Town, Japan, replaced three existing 175 MW coal fired plants that started commercial operation more than 50 years ago. The new and cleaner single shaft combined cycle plant burns natural gas with 60 percent CO2 emissions reduction and considerable NOx emissions reductions.
|Sendai Thermal Power Station|
The new plant operating mode is based on a daily start and stop duty cycle to compensate load variability in the area. As an economic benefit, the plant will provide a thermal efficiency boost from 43 percent to 58 percent, representing a fuel savings. The plant is one of the first applications of the Mitsubishi M701F4, Mitsubishi Heavy Industries’ (MHI’s) most recent 50Hz F class gas turbine upgrade. This machine incorporates changes to six compressor stages to increase air flow by 6 percent.
CO2 emissions were reduced by replacing the existing plant with the new high efficiency combined cycle. Natural gas replaced coal, cutting 40 percent CO2 emissions, and increasing the thermal efficiency of the plant reduced CO2 emissions by an additional 20 percent. Another 1,000 ton CO2 annual reduction is expected in 2012 by the integration of a mega-solar system to be installed at this plant site.
Waste water reduction from 2,000m3 to 730m3/day was achieved by eliminating flue gas desulfurizer (FGD) resulting from the reduction of SOx emissions associated with natural gas fuel.
Construction work for the new plant took place while demolition of the existing plant was underway. This created several challenges for the team, including space restrictions and crane access. Since the plant is also located in a residential area, provisions were made to reduce noise, such as noise prevention sheets at the site boundary and the selection of low-noise and low-vibration machinery.
The Sendai station is located in the vicinity of the Matsushima Prefectural Natural Park. Special consideration was applied for the external appearance of the building, which incorporates images of Japanese traditional architecture. A white façade with tile roof design was applied. The disruption of natural landscape was minimized by reducing the number of stacks from the original three to one, as well as minimizing the stack height from the original 120 m to 59 m.
Syracuse University Green Data Center
Constructed in six months and showcased to the public in December 2009, the Green Data Center at Syracuse University in New York is one of the world’s most energy efficient data centers. The 12,000-square-foot facility uses 50 percent less energy and produces fewer greenhouse gasses than traditional data centers, which is significant because energy consumption in data centers is often 30 percent higher than commercial buildings.
The Green Data Center is one of the first in the world to combine technologies such as hybrid UPS microturbines, absorption chillers, IBM-developed cooling doors on each server rack that use chilled water to maintain constant server temperatures, a rooftop cooling tower and onsite conversion of utility AC power to DC power.
Primary power for the Center comes from 12 natural-gas fueled Hybrid UPS Capstone microturbines. This system is one of the first on-site power systems to integrate C65 (65 kW) microturbines directly with a dual-conversion UPS to provide power for mission-critical loads. The hybrid turbine design generates power while also using utility power to meet the electrical load demand. This allows the system to operate at the optimum level, balancing the electrical requirements and heating and cooling demand. Although 12 microturbines are installed at the data center, a maximum of 10 are used at one time to power the servers and equipment. Depending on the data center’s fluctuating power needs, the number of microturbines producing power strictly for the center varies from five to 10. The remaining microturbines produce extra power that is shipped to the university power grid or the building next door.
In the event utility power is lost, the system will assume the electrical load. A battery bank with enough power to carry the maximum load for 17 minutes is available for catastrophic situations.
Another technology that boosts the facility’s energy efficiency is a water-side heat exchanger, which produces chilled water from the cooling tower on the roof. During favorable weather conditions, the cooling tower produces 45-degree water that provides another source of chilled water to cool the facility.
Because of the low-emission Capstone microturbines, the Green Data Center emits significantly lower emissions than traditional data centers and is a model for the future of data centers.
Langage Combined Cycle Plant
The Langage Power Station project in Langage, United Kingdom was acquired by Centrica Langage Ltd., a unit of Centrica Energy, in August 2004. Operation began in March 2010.
The plant is an 878 MW KA26-2 multi-shaft 2-on-1 combined cycle plant, which features two GT26 gas turbines, each driving its own air-cooled (TOPAIR) turbogenerator and each with an associated heat recovery steam generator (HRSG) to feed a single common type STF30C steam turbine, all supplied by Alstom. Langage was built under a turnkey engineering, procurement and construction contract.
The KA26 combined cycle can be run at partial load—from 40 percent or below to 100 percent load—to meet variable demand requirements while maintaining low levels of emissions. The key feature of the KA26 is the GT265 gas turbine’s sequential combustion system or reheat cycle concept. Compressed air is first heated in a combustion chamber by adding about 50 percent of the total fuel. After this, the combustion gas expands through the single stage high-pressure turbine, which lowers the pressure by about a factor or two. The remaining fuel is added in the second combustion chamber, where the combustion gas is heated a second time to the maximum turbine inlet temperature and finally expanded in the four-stage low-pressure turbine. This operational flexibility provides high part load efficiency, low NOx emissions and flexibility regarding gas composition.
The plant in southwest England is in an area that has little existing generation capacity. This will reduce the need to import power from the rest of the country and lower transmission costs.
The plant building is covered with a cladding that was designed to be aesthetically pleasing and to keep noise to a minimum. The noise guarantee is 35 dBA at specific locations near the plant. This means that the noise produced from the plant is less than the ambient background noise from nearby highways, rivers and wildlife.
The plant has a curved green roof and has been set into the ground to minimize its impact on the horizon. The stack has also been made into an architectural feature through the use of a mesh covering, creating a design style similar to that of a modern airport.
Best Nuclear Project
New-generation tungsten shield project at Arkansas Nuclear One
The development of new-generation tungsten shields at Arkansas Nuclear One (ANO), operated by Entergy, is the Nuclear Project of the Year. ANO attempted to look beyond conventional materials such as lead, steel and water for methods in shielding applications. The result was the development of a flexible, heat-resistant shielding made of tungsten and iron metal powder immersed in silicone polymer.
|Arkansas Nuclear One was the site of an innovative shielding technique|
The project consisted of two parts. The first entailed shielding the source. The shielding employs a new method of attaching using imbedded magnets that form fit with ease. Lead blankets have been the backbone of shielding applications in the past, but ANO found the tungsten shield to be twice as effective as lead in lowering exposure rates to the worker.
The tungsten shield weighs 25 to 50 percent less than lead while removing the accompanying toxicity hazard and mixed waste processing costs. This significant weight reduction resulted in improved industrial safety conditions and reduced worker fatigue. In total, the shielding resulted in $319,000 total savings.
Part two of the tungsten shielding project was shielding the person. By using a tungsten vest, the team’s theory was, “If you can’t shield the source, shield the person.” The ANO team found the fabricated tungsten vest to provide better radiation protection than a lead application, proving to be more effective at stopping gamma rays.
The ANO team found that wearing a tungsten vest eliminates building temporary shielding racks and avoids exposure for short duration evolutions. All material used in the tungsten shielding vest is non-toxic and non-hazardous waste, eliminating such concerns that are associated with lead shielding. Exposure to the welders was reduced by 39 percent through the use of the tungsten vests. The total exposure avoided was 642 person-mRem.
Gimbaled head project at Palisades Nuclear Power Plant
The honorable mention for Nuclear Project of the Year was also an Entergy-owned project, the gimbaled head project at the Palisades Nuclear Power Plant in Covert, Mich. In March 2002, workers repairing a control rod drive mechanism (CRDM) nozzle at the Davis-Besse Nuclear Power Station in Ohio discovered a football-sized cavity in the reactor vessel head. This discovery was linked to two similar discoveries 15 years earlier. As a result, the Nuclear Regulatory Commission initiated a regulation requiring all owners of pressurized water reactors to take specific measures to protect plant equipment from boric acid corrosion caused by primary water stress corrosion cracking.
While Palisades was in the process of replacing the reactor head, plant engineers also improved the inspection drive for both CRDMs)and the in-core instrumentation (ICI) nozzles. Portions of the inspections were in hard-to-reach areas and required critical path time. The Palisades team decided to address the need for a better solution both for their plant and the industry.
Palisades, along with Areva, developed the gimbaled head solution. A gimbaled head is a low-mass head-flexure assembly for reading and writing information scanned from nozzle volume to external hard drive. The challenge in developing the gimbaled head was threefold. The team needed to obtain a smaller transducer footprint while packaging the gimbal motion. They also needed the ability to retract the transducers when required while getting adequate couplant to the transducers. And they needed to reach all areas of interest.
The gimbaled head device minimized the transducers’ footprint through the implementation of a new water delivery and retrieval system. With a smaller footprint, the team was able to incorporate a gimbal design similar to one currently used on the vessel inspection tool, capable of accessing difficult areas. The new design eliminated the need for OD ultrasonic transducer; a 50 percent savings in mechanical instrumentation and capability of performing both inspections with one device.
Palisades had never completed the inspection of the CRDMs in less than 150 hours prior to using the gimbaled head. In 2007, the inspection time dropped from 150 hours to 92 hours for the CRDMs only. The overall outage time in 2009 fell from the baseline of 150 hours to 109 total hours for both CRDMs and ICI inspections using two of the delivery platform robots, SUMO-Rockys, simultaneously. With some continued improvement, the Palisades and Areva team were on track to go to sub-100 hours in 2010 on the total inspection.
Best Renewable/Sustainable Project
Tekeze Hydropower Project
The Tekeze Hydropower project in Ethiopia, located a tributary of the Nile, is the Project of the Year for renewable/sustainable projects. The $350 million project, funded by the government of Ethiopia and owned by Ethiopian Electric Power Corp., adds 40 percent more electric capacity to the country and was the largest public works project in Ethiopia’s history at the time of construction. Due to the lack of natural resources and the cost of imported fuels, power generation in Ethiopia comes primarily from hydroelectric sources.
Tekeze Hydropower’s 300 MW lifted Ethiopia’s generating capacity by 40 percent.
The Tekeze Hydropower project is the tallest arch dam in Africa at 188 meters. The 300 MW facility includes a double curvature concrete arch dam, a method of design that minimizes the amount of concrete used. It created a reservoir 70 kilometers in length. An underground powerhouse containing four 75 MW Francis Turbines sits 500 meters downstream of the dam and is fed by a 75-meter-high intake structure connected by a 500-meter-long concrete-lined power tunnel. A 230 kV double-circuit transmission line 105 kilometers long was constructed through mountainous terrain to connect to the Ethiopian national grid.
The project’s beginnings date back to 1995 when the Ethiopian Ministry of Water Resources conducted a study identifying the site as one of two preferred dam sites for hydropower development. MWH joined the project in 1998 and made modifications to an existing design for the dam, powerhouse and tunnel system, resulting in cost savings.
A multi-stage impoundment approach was implemented during construction, which allowed the river diversion to be closed in May 2007, nearly two years prior to dam completion. This allowed for more than 3 billion m3 of water to be retained, advancing generation by more than one full year. The value of the water captured via early impoundment was worth approximately $40 million. In addition to power generation, the Tekeze dam enables regulation of river flow, allowing downstream communities year-round access to the water supply.
A 10-year 2000m3/sec flood on Aug. 9, 2006 was an unexpected test for the dam. The dam proved its ability as a gravity structure and no damage was incurred to any of the permanent structures.
Local community infrastructure was improved as a result of the project, including construction of more than 40 kilometers of roads and installation of the first communications links from the area to the outside world. Also as a result of the project, education was improved in the area as the wife of the MWH chief design engineer spearheaded efforts to build a new school near the village of Seboko. The school was financed by contributions from engineers, contractors and staff working on the project, local residents and a supportive local government.
On-the-job training was also provided to locally-hired employees. Ethiopian Electric Power Corp. implemented programs to provide education and training to local workers. Programs included education to combat AIDS, malaria and other safety, health and welfare issues affecting the local community.
Canoe Creek Hydroelectric Project
Canoe Creek Hydro is a 5.5 MW run-of-river hydroelectric facility on Vancouver Island that provides power to a remote community on the island and helping the island become less reliant on mainland power. The facility is owned and operated by the Tla-o-qui-aht First Nation and located in the heart of the Nation’s Tribal Parkland. The Barkley Project Group Ltd., along with Amnis Engineering and Hazelwood Construction One, worked with Vitaulic, a manufacturer of mechanical pipe joining solutions, to develop Canoe Creek. Construction started in May 2009 and ended in May 2010. The plant went into service in June.
Canoe Creek Hydro operates by diverting stream flow into a penstock at a high elevation– up to 84 percent grade – intake. This made construction a challenge, as did the facility’s location in the Pacific Rim Rainforest, where annual precipitation is amongst the heaviest in the world, particularly in the winter months when construction took place.
Constructing the 4-km-long penstock line in these conditions using welding techniques would have proven difficult. Instead of using mechanical welding on the penstock, the companies used mechanical couplings. In the field, the couplings proved advantageous in many ways. For example, couplings could be installed in any weather condition with no special requirements. Couplings also reduced the amount of excavation, bell holing and dewatering that would be common with welding.
Couplings also improved site safety. As the pipe was already on site, Hazelwood grooved and re-coated the pipe prior to sending it up the single-lane logging road for assembly. In addition, the replacement of welding with mechanical joints allowed for a reduction in the number of laborers required on the job site. Canoe Creek also employed local laborers.
Environmental benefits were also gained by replacing welded joints with mechanical joints. Welding one kilometer of straight-run 36-inch pipe produces about 40,338 kg of CO2 emissions using a diesel-powered machine and 9,463 kg of CO2 emissions using an electric-powered machine. Grooving and coupling that same run of pipe produces 62 kg of CO2 emissions. The use of couplings also reduced the amount of x-raying required on site, reducing radiation emission. PM, CO2 and radiation were reduced, as well as electrical energy use.
Magic Hat Brewery biogas facility
This biogas facility project at the Magic Hat Brewery in South Burlington, Vt. allows the owner, Purpose Energy Inc., to use organic waste streams and generate biogas. The biogas is then used by the brewery’s steam boilers and/or PurposeEnergy’s cogeneration plant. In mid-2008, Pizzagalli Construction Co. was selected as the design/build partner for this $3.4 million project at New England’s largest craft brewery. This brewery waste recovery system was developed by CEO and founder of Purpose Energy, Eric Fitch.
Underground process piping, stone aggregate piling for the digester, structural excavation and backfill and all of the concrete work began in December 2009. A 1,600 square foot mechanical building was built and a digester tank was installed. The piping process was completed by May 2010 and the facility began operations in June 2010.
PurposeEnergy’s Biphase Orbicular Biodigester was designed for brewery by-products and enables the conversion of high solids content brewery waste into carbon neutral, renewable biogas. This system is also designed to utilize the waste heat from the generator’s exhaust, coolant and engine oil to heat the digester and preheat the water used in the brewing process.
The Purpose Energy project has brought many benefits to the facility and environment. By diverting the waste stream created during the brewing process, the brewery’s operating costs have been reduced as Magic Hat Brewery no longer needs to pay for waste treatment surcharges, thereby reducing traffic, noise and air pollution that would result from the transportation of the waste. In addition, the use of this technology creates a clean, carbon neutral energy source that decreases the effects of greenhouse gases on the environment.
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