Clyde Bergemann EEC (CBEEC) has completed a three-year environmental improvement project for NRG Energy, Inc. that reduces air emissions beyond requirements with lower operating costs, and minimized boiler outage time. The project retrofitted two of NRG’s coal-fueled power plants in New York, the Dunkirk and Huntley Generating Stations, totaling six boilers and a nominal generating capacity of 1000MW, with state-of-the-art environmental control systems. The work, valued at more than $170 million, included engineering, procurement, construction, and commissioning. The project was completed within tight construction and outage schedules that allowed NRG to maximize service to its customers. Independent organizations have tested the systems and determined that they outperform guarantees on emissions reductions, leading to lower than expected operating costs.

This project is the first of its kind in the United States in which trona and powder-activated carbon (PAC) are simultaneously injected into the flue gases thereby reducing sulfur dioxide (SO2) and mercury (Hg) from the plant’s exhaust. When NRG sought to reduce emissions of particulates, SO2, and mercury at the two stations, the company selected CBEEC's environmental control technology based on its ability to meet the emissions requirements while significantly limiting the outage time required for installation. CBEEC’s solution allowed for installation of most of the modular equipment while the power plant remained in operation.

For this project, CBEEC engineered and supplied all Air Pollution Control (APC) equipment and ancillary systems down to the foundations. The project included demolishing existing equipment, erecting new equipment, hot to cold ductwork conversions of all 12 air heaters, piping, low and medium-voltage electrical work, and thermal insulation. CBEEC managed various phases of the project and contributed to meeting the critical milestones and outage dates.<

New emissions controls included:

10 Pulse-Jet Fabric Filters each with 12 shop-fabricated modules utilizing long bag technology

6 trona storage and injection systems including 7 equipment buildings and 6000 feet of transport piping to reduce SO2 emissions

2 trona railcar unloading and 6 transfer systems and associated bulk storage silos

6 PAC injection systems to reduce Hg emissions

3 PAC unloading and storage systems

10 pneumatic dense-phase ash handling systems, including 120 ash vessels

2 ash-storage silos and unloading systems (ash and associated storage silos)

12 ID fans, including 2500/1500 HP motors and VFD's

Over 6000 linear feet of elevated ductwork (nominal 16.5' square) and support towers

Compressed air systems, including receivers and dryers

14 Electrical equipment buildings including all associated MCC's and VFD's (controls)

6 integrated DCS Control Systems for all CBEEC equipment (Interface)

Other Balance of Plant items, including elevators, CFD model study for each APC/ductwork train, fire protection equipment, pipe bridges, equipment enclosures and complete structural analyses with modifications to existing boiler buildings.

Performance tests indicate that emissions of SO2 are reduced by over 55%, mercury levels reduced by over 90%, and particulate levels reduced to less than 0.010 lbs/MMBtu. All three exceed the guaranteed performance levels. Sorbent injection rates are well below those guaranteed and combined with lower than guaranteed pressure losses and power consumption will save in operating costs over the lifetime of the systems.

Overall benefits of the CBEEC solution include low operating costs, low installation costs, and a cleaner environment while burning America’s most abundant and lowest cost fuel--coal.