1、Navajo Generating Station主講人：牛蘭利Contents introduction1History2 Design and specifications3Performance4Environmental controls6Economic aspects5IntroductionIntroductionIntroductionNavajo Generating Station is a 2250 megawatt coal-fired powerplant. This plant provides electrical power to customers in Ar

2、izona, Nevada and California. It also provides the power for pumping Colorado River water for the Central Arizona Project, supplying about 1.5million acre feet (1.85km3) of water annually to central and southern Arizona. As of 2013 permission to operate as a conventional coal-fired plant is anticipa

3、ted until December 22, 2044. The Navajo Generating Station is the United States of Americas third largest emitter of carbon dioxideIntroduction it locates on the Navajo Indian Reservation, near Page,Arizona, United States Historyin 1950s and 1960s designin 1970 start in 1974units 1 completed in 1974

4、units 2 completed in 1974units 1 completed NGSbuildingDesign and specifications The plant has three identical 750 MW steam electric generating units. Major components of each unit include a boiler, turbine, generator, closed-cycle cooling system, and environmental control equipmentDesign and specifi

5、cationsThe boilers are tangentially fired, balanced draft, reheat type steam generators, supplied by Combustion Engineering Designed for supercritical operation, each boiler supplies up 5,410,000 pounds of steam per hour to the turbines at 3500 psi (241 bar) and 1000F (537C）The main turbines are Gen

6、eral Electric (GE) tandem compound reheat turbines, each directly coupled to a generator and designed to rotate at 3600 rpm.The plant uses about 26,000 acre feet (32,000,000m3) of water per year from Lake Powell, or about 1/2 gallon (1.9L) per kWh, mainly for cooling water and scrubber operationThe

7、coal is hauled 75 miles from mine silos to the plant by the BM&LP electric railroad that is owned and operated by the plantPerformanceThe plantThe gross capacity is 2409.3 (MW) or 803.1 MW per unitA net nameplate capacity of 2250 MW or 750 MW per unitthe rated power output leaving the plant through

8、the transmission linesEconomic aspects NGS has 538 employees, and pays about $52 million per year in total wages NGS being the sole source of revenue for the mine. The plant and mine annually pay out about $100 million in direct wages and $50 million in leases and royalties NGS and Kayenta Mine paym

9、ents in 2012 accounted for about a quarter of the Navajo Nations revenues, and 65% of the Hopi Tribes revenues, resulting in about 850 direct tribal positionsEnvironmental controlsFlue gas emissions Prior to installation of the scrubbers, SO2 emissions were about 71,000 tons per year Prior to 2009 w

10、hen installation of the new burners began, NOx emissions were about 34,000 tons per yearEnvironmental controlsEnvironmental controls Fly ash particulate is removed from the flue gas by hot-side electrostatic precipitators (ESPs) and SO2 scrubbers. The ESPs, constructed as part of the original plant,

11、 remove 99% of particulate. Scrubbers remove an additional 50% of what remains in the flue gas after passing through the ESPsEnvironmental controlsWastewater handlingNGS was built with one of the first zero liquid discharge (ZLD) systems in a power plant, recovering all cooling tower blow-down and r

12、unoff from developed areas of the site。 The waste water is processed through three brine concentrators and a crystallizer, which remove the solids and produce distilled water for re-use within the plant Several lined ponds are used in conjunction with the ZLD system to capture and regulate the flow of waste water to the systemEnvironmental controlsByproducts handling The plant sells about 500,000 tons of fly ash per year for use in the manufacture of concrete and Flexcrete insulating block building product Bottom ash and gypsum, a byproduct of