micro turbin

دانلود PDF Microturbines |Microturbines are small combustion turbines that produce between 25 kW and 500 kW of power. Microturbines were derived from turbocharger technologies found in large trucks or the turbines in aircraft auxiliary power units (APUs). Most microturbines are single-stage, radial flow devices with high rotating speeds of 90,000 to 120,000 revolutions per minute. However, a few manufacturers have developed alternative systems with multiple stages and/or lower rotation speeds. Microturbines are nearing commercial status. Capstone, for example, has delivered over 2,400 microturbines to customers (2003). However, many of the microturbine installations are still undergoing field tests or are part of large-scale demonstrations. Photo Source: Capstone Microturbine Overview Commercially Available Yes (Limited) Size Range 25 – 500 kW Fuel Natural gas, hydrogen, propane, diesel Efficiency 20 – 30% (Recuperated) Environmental Low (< 9 – 50 ppm) NOx Other Features Cogen (50 – 80°C water) Commercial Status Small volume production, commercial prototypes now. Microturbine generators can be divided in two general classes: Recuperated microturbines, which recover the heat from the exhaust gas to boost the temperature of combustion and increase the efficiency, and Unrecuperated (or simple cycle) microturbines, which have lower efficiencies, but also lower capital costs. While some early product introductions have featured unrecuperated designs, the bulk of developers' efforts are focused on recuperated systems. The recuperator recovers heat from the exhaust gas in order to boost the temperature of the air stream supplied to the combustor. Further exhaust heat recovery can be used in a cogeneration configuration. The figure below illustrates a recuperated microturbine system BACK TO TOP DESCRIPTION A. What is a Microturbine? Microturbine Overview Commercially Available Yes (Limited) Size Range 25-500 kW Fuel Natural gas, hydrogen, propane, diesel Efficiency 20-30% (Recuperated) Environmental Low (<9-50 ppm) NOx Other Features Cogeneration (50-80°C water) Commercial Status Small volume production, commercial prototypes now. (Courtesy of California Distributed Energy Resources Guide on microturbines) Microturbines are small combustion turbines approximately the size of a refrigerator with outputs of 25 kW to 500 kW. They evolved from automotive and truck turbochargers, auxiliary power units (APUs) for airplanes, and small jet engines. Most microturbines are comprised of a compressor, combustor, turbine, alternator, recuperator (a device that captures waste heat to improve the efficiency of the compressor stage), and generator. The figure below illustrates how a microturbine works. How a microturbine works (Courtesy of slimfilms.com) Microturbine Cost Capital Cost $700-$1100/kW O&M Cost $0.005-0.016/kW Maintenance Interval 5000-8000 hrs Microturbine capital costs range from $700/kW for larger units to approximately $1,100/kW for smaller ones. These costs include all hardware, associated manuals, software, and initial training. The addition of a heat recovery system adds between $75 - $350/kW. Site preparation and installation costs vary significantly from location-to-location but generally add 30-70% to the total capital cost. Microturbine manufacturers are targeting a future capital cost below $650/kW. This appears to be feasible given the market expands and sales volumes increase. With fewer moving parts, microturbine vendors hope their units can provide higher reliability and require less maintenance than conventional reciprocating engine generators. Manufacturers expect that initial units will require more unexpected visits, but as the technology matures, a once-a-year maintenance schedule should suffice. Most manufacturers are targeting maintenance intervals of 5,000-8,000 hours. Actual maintenance costs and intervals for mature microturbines are less well known since there is a limited base of empirical data from which to draw conclusions. Estimated forecasts range from $0.005-$0.016 per kWh, which would be comparable to costs for small reciprocating engine systems. .