Kawasaki Gas Turbines Cogeneration System Helps Bridgewater Correctional Facility
Houston, Texas - January 25, 2010 - The Bridgewater Correctional Complex (BCC) recently completed the installation of a Gas Turbine Cogeneration System that helped to increase the overall energy efficiency of the facility while simultaneously reducing gaseous emissions such as NOx, CO, and CO2. For its efforts, this 785,000 square foot Massachusetts facility was awarded a prestigious EPA Energy Star CHP award.
In what otherwise would be wasted heat this Cogeneration (or Cogen) system recovers exhaust from the turbine and uses it to produce steam. That steam is used to support the daily heating, cooking, cleaning, and domestic hot water needs of the complex. Operation of the CHP system also allowed the Department of Correction to shut down an old and more-polluting diesel engine generator.
The CHP system employs a Kawasaki natural gas-fired combustion turbine which generates nearly 80 percent of the facilities annual electricity demand. Equipped with Kawasaki XONON combustors, the NOX emissions from the turbine are low enough to meet NOX emission requirements without the need for add-on pollution controls. The nominally rated 1.4 MWe (at ISO) Gas Turbine Generator Systems is a Kawasaki GPB15X, manufactured by Kawasaki Gas Turbines – Americas (Houston, TX), which is wholly owned by Kawasaki Heavy Industries (KHI).
COGENERATION, COMMON SENSE
The Massachusetts Division of Capital Asset Management (MA-DCAM) opted for a cogeneration system in 2004, as the facility has a year-round need for both Steam, and Electricity. The Gas Turbine was selected (higher up front cost), as it could deliver a near 80% net thermodynamic efficiency by supplying both electricity and high-energy-steam (high-pressure-superheated-steam). Although a Natural Gas Reciprocating Engine Generator (lower up front cost) was an option, the overall thermodynamic efficiency was much lower (as Recip Engines produce very little high energy steam), and did not yield a sensible economic and environmental solution.
Before the GPB15X Cogeneration System went on-line, Bridgewater Correctional Complex (BCC) purchased all of their electricity, and produced all of their steam via on-site boilers. With the Kawasaki Energy solution, BCC now generates approximately 1.4 MWe and 11 MMBTU/hr all from the same input fuel stream that is clean natural gas. Given today's very favorable natural gas prices (i.e. Spark-spread); MA-DCAM is realizing a handsome payback on the Kawasaki Investment they made only a few years back. The GPB15X, it's not just economics, it's also the environmentally correct thing to do.
HOW IT WORKS
The key to achieving these levels can be found in the Kawasaki GPB15X's ability to keep air-pollutant emissions extremely low. That is accomplished by using the proven Catalytic-Combustion-System. Kawasaki purchased the rights to use this technology several years back, and it is now known as "K-LEAN". Due to market recognition, the GPB15 still retains the "X" symbol. The Catalytic Combustor is not Selective Catalytic Reduction (SCR), nor is there a catalyst hidden inside of a standard flame-combustor. Catalytic Combustion is exactly as stated, the air-fuel-charge catalyzes across the catalytic (proprietary) materials inside of the combustor, and heat is released. This means the catalytic reaction occurs at sub NOx formation temperatures, thus there is nearly no NOx, and very little CO produced from this very efficient catalytic-combustion-reaction.
The GPB15X may be permitted in all states in the US, without any further need for secondary (post-combustion) NOx emissions controls treatment. Typically, SCR's require a reagent such as ammonia (NH3), to chemically react with a catalyst in the flue-gas-stream. Ammonia storage, and its usage, is not required with the GPB15X Technology. Many facility operators prefer to keep ammonia off of their sites, as it does pose potential site hazards.
The GPB15X is equipped with a single-silo-type-combustor (mounted directly atop the engine) tuned to fire pipeline quality natural gas only with the X-Option. Kawasaki also has Dry Low Emissions Systems (known as DLE which uses a flame, not catalytic combustion) that can fire both natural gas and or #2 fuel-oil (for sites that require dual-fuel-capability).
Kawasaki uses several well know control platforms for the GPB15, some are shared with the GPB15D and now the GPB15D+ (nominal 1.7 MWe ISO Rated Unit). Control is achieved through sensors, flow-meters, and advanced computer-controls that optimize combustion of the natural gas fuel, and thereby keep emissions as low as possible.
The turbine generator control system controls both the turbo generator set (such as maintaining power set points), and controls parallel operation with the Utility Grid (external to the facility). It takes full control if required for Island Mode (also known as ISOCHRONOUS OPERATION).
The GPB15X Control System easily tracks facility load requirements, seamlessly meshes output with the Utility Grid. Per industry norms, Kawasaki can diagnose, and monitor the Gas Turbine Generator system remotely (and via data-logger-archiving), if required. And, dispatch its own US Based field service personnel to site in order to maximize unit up-time, and system availability, 24/365.
COMPLETE POWER ISLAND PACKAGE
Kawasaki not only supplies Gas Turbine Generator Systems, but also works with partnering technology company to provide, Heat Recovery Steam Generators (HRSG"s), and Natural Gas Fuel Compressors (NGFCs), thereby providing one-stop shopping for its clients. The Bridgewater Correction Complex is equipped with both a HRSG, and Natural Gas Fuel Compressor. Kawasaki has a 19 year contract currently in place to maintain its equipment under an ESA agreement (aka LTSA). Kawasaki also works with Engineering Firms and Constructors to supply complete Cogen Solutions.
BCC, A GOOD NEIGHBOR
The GPB15X Cogen Facility at BCC quietly goes about its duties, year round, while abiding by Massachusetts' strict emissions requirements (Among the strictest in the US for NOx, CO, UHC, and PM. The GPB15X Cogen has now logged 3+ years of continuous base-load-operation, and has also improved the CO2 Footprint, and energy consumption efficiency for the State of Massachusetts.
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