The Diagnosis Of Efficiency Of Pulverized Coal-fired Boiler And Analysis Of High Temperature Corrosion

The aim of this paper is to raise the boiler efficiency and ensure the boiler safety.Boiler efficiency and high temperature corrosion are the objects of the paper. Heat loss due to exhaust gas and mechanical incomplete combustion heat loss are almost 90%percentage of total heat loss of boiler.Both of two items in heat loss of boiler efficiency are mainly studied in the paper.The two items and high temperature corrosion are discussed in theory,influence factors,site diagnosis and analyzed with lots of cases.In site diagnosis,the main influencing factors are found out from many influence ones,diagnosis and reform scheme which is easily operational are made out.In heat loss due to exhaust gas,the study objects are exhaust gas temperature and excess air ratio.In theory,the traditional methods calculating heat loss due to exhaust gas are based on element analysis,it is inconvenient for its complexity in thermal power plants.It is of great engineering significance to calculate heat loss due to exhaust gas based on proximate analysis.After defining a new input heat,the calculating formulas based on proximate analysis are deduced by a series of formula derivation,which is the key point of innovation of the paper.Air leakage of environment and air pre-heater are mainly studied in the study of exhaust air ratio.The general monitoring objects are the excess air ratio of furnace hearthα_lt^H and exhaust gasα_py in boiler operation,due to air leakage of environment and air pre-heater,it is not precise to judge the appropriate air quantity only byα_lt^H andα_py.The calculating formulas of theoretical air volume related to given boiler load are received through connecting boiler load and theoretical air volume,the excess air ratio of inlet to air pre-heater can be calculated by actual air quantity measurement,which enhance the accuracy of air quantity diagnosis compared to general methods.The air quantity calculating method associated to three highest air velocity which is based exponential law for velocity distribution in different Reynolds number is put forward,which can be used to verify the actual measurement and rapidly measure air quantity.The boilers of Qilu Petrochemical Company heat and power plant(HG-410/100-11) are used to illustrate the actual diagnosis.Another important factor related to heat loss to gas exhaust is exhaust gas temperature,the four main influencing factors are discussed,while discussing the influence of air leakage,the property of air leakage-temperature variety of boiler heating surface is put forward.According to it,the following conclusion is received:the boiler radiative heating surface,such as furnace hearth and platen super-heater,cause temperature-increase effectiveness;the boiler convective heating surface,such as economizer and air pre-heater,cause temperature-decrease effectiveness.The key diagnosis points are presented in actual diagnosis of exhaust gas temperature,the case of boiler are illustratedUnburned carbon content is the main studying object in the study of mechanical incomplete combustion.The main influencing factors related to unburned carbon content are discussed,the key diagnosis points are pointed out in actual site diagnosis.The boiler #1 of Qilu Petrochemical Company Heat and Power Plant are used to illustrate the actual diagnosis.Mechanism and precaution measures related to high temperature are discussed in the paper.Unevenness of primary air velocity distribution resulting to circle cutting deviation in furnace hearth is mainly discussed in actual site diagnosis.The boiler #1 of Qilu Petrochemical Company Heat and Power Plant are used to illustrate the actual diagnosis.