Research On Economy Of The Low Temperature Economizer Combined Air Heater System Of 1000MW Unit Of Power Plant

Generally,most domestic coal-fire power plants have the problem of high exhaust gas temperature due to various reasons like slagging on heat exchange wall,ash blocking,changes of fire coal types and different operators’ experience;these not only affect heat economy of the unit,but also the safety and reliability of tail equipment.At the same time,reducing dust discharge in exhaust gas has already been an urgent problem for some coal-fire power plant along with the carry-out of new pollutants discharge standard.Obviously,the further utilizing of waste gas heat is an important technical improvement of power plant.This article researches the influence of low temperature economizer in collaboration of wind heater,heat economy and notices during operation;it has important practice engineering value.This essay analyzes different system characteristics to different layouts of lowtemperature economizer based on the 1000 MW ultra-supercritical units.A corresponding mathematical model is built to calculate its running characteristics after the layout is fixed.The boiler heat economy change caused by the applying of wind heater and the turbine efficiency change caused by the rise of condense water are researched.Then,the best mean temperature in cold side of wind heater is approached under the constraint of meeting the lowest technical temperature requirement.The influence to the down-steam facilities,like electrostatic precipitator,induced draft fan and the desulfurizing tower,is assessed.The results show that after reform the dust concentration in exhaust gas is effectively reduced at the outlet of precipitator,meeting the requirement of super-clean emission.But different conditions result in different power of the induced draft fan and water consumption of wet desulphurization process can be reduced This essay gives out a summary and analysis about how to calculate the acid dew point based on the research around the world.The relation between the wall temperature and the corrosion speed is generated from the influence on the wall temperation variance to the sulfuric acid concentration and the relation on the sulfuric acid concentration to the metal corrosion,then confirm the corrosion area around the water dew point.According to the relation between the corrosion spike and acid dew point from the reference,the corrosion area around the dew point is comfirmed.Based on the corrosion area,the corresponding maximun and minumun temperature with different condition and coal quality in this area can be calculated and the rule is analyzed.Thus,related parameters are monitored to mitigate the corrosion on the low-temperature economizer.This essay analyzes the notes when low-temperature economizer combined operating with air heater,and the notes while the system washing,draining,leaking and isolating.And the notes under normal operation are analyzed to ensure the maximiun profit while garanteeing the satefy.