| The company of Longshan put two 600 MW direct air cooling generating units into operation in 2007. Steam turbine is ZKN600-16.7/538/538 subcritical, once reheat, fou cyliner and four exhaust, direct air cooling coagulation turbine. Unit's specified load is600 MW, and 645 MW under TMCR condition. Because of the history reasons and the price rise of coal, the back pressure is generally high and the operation economy of the unit is low in summer. For reducing the back pressure, spray cooling system is introduced by Longshan power plant. As results, a lot of demineralized water is wasted,the generation cost rise, and scaling concurs is found on the surface of radiator.For solving above questiones, Longshan power plant introduced dry and wet cooling system as optimization of cold end. It will shunt part of exhaust steam to peak cooler, and these steam is cooled by open cycle cooling system. The main parts of thesis are as follows:( 1) The article introduces the technological process of system and the rebuild design of air cooling part, engine, hydraulic technology, chemical water treatment and thermal control.(2)By the theoretical calculation of dry and wet cooling system, the author obtain the best divided percentage of steam and calculate the energy saving and economic benefit of system under the best divided percentage of steam. It can find the system has great energy-saving effect and economy, the energy-saving effect is better than spray cooling system.(3)the article makes performance test for direct cooling system and peak cooling system under 300MW?450MW and 600 MW load and find optimal operation mode under different conditions. |
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