| How to reduce dioxins from waste incineration and power generation has beenwidely concerned. And in addition to further in strict accordance with the principle of’3T+E’ to ensure the waste complete combustion and flue gas treatmentprocess optimization, the key is to reduce the the incinerator shutdown and cold starttimes. However, due to the relatively high content of MSW dust, glass and salt, inhigh temperature conditions with the fly ash easy melting and sintering, it will bringthe incinerator coke fouling problem, which will not only reduce boiler thermalefficiency but cause high-temperature corrosion significantly. And it will even causeserious throat flow area of the incinerator to reduce or super heater tubes damage,which will cause incinerator shut down or maintenance accident. Finally it willbecome the main obstacle for waste incinerator with abnormal conditions increasing,dioxin emissions control harder and energy conservation more difficult as well.In this paper, the characteristics of MSW in Changzhou city were analyzed. Andcombined with Guangda Changzhou Incineration Plant mechanical grate incineratorcharacteristics (2×400t/d); the mechanical grate incinerator coking fouling point wasidentified. And it is found that the main coking point is in the front and rear archformed the throat area and the first and second row tube panel of the super heater. Thefouling occurs mainly at the horizontal flue gas part. With the combination of cokingand fouling part field data analysis and comparation, it is concluded that the MSWincinerator is easier to produce coking and fouling phenomenon than normal coalcombustion boiler.According to the incinerator coking and fouling characteristics in Changzhou plant,several aspects were analyzed in this paper, including the incinerator temperature,heat boiler structure, air supply, ash cleaning effect, fluctuation of the waste heatingvalue, and the impact factors were studied. Consequently, the control measures forincinerator coking and fouling were developed, mainly including the operation modeoptimization, scientific management and equipment modification, with details asfollows:(1) maintain the furnace outlet temperature between870℃-960℃, which will not only ensure the dioxins decomposition, but also meet the requirement of theboiler evaporation,(2) the primary and secondary air supply ration and temperaturecan be optimized depending on the seasonal and waste fermentation differences,(3)based on the horizontal flue differential pressure as well as the2,3flue outlettemperature integrated to determine and adjust the class the soot blower frequency,(4)control the furnace temperature in the reasonable range with leachate back spraytechnology,(5) adding sealed wind for the pulse soot blowers to prevent corrosion ofpulse soot pipeline in order to ensure the effect of pulse soot blowers,(6)#2,#3flue ash outlet changed to the drop part to reduce the amount of fly ash in the furnacecycle as well as decrease the fly ash coking and fouling chance.Through implementation of above measures, the coking and fouling speed ofmechanical grate incinerator can be effectively slowed down with the incineratoroperation cycle extending significantly as well. The average incinerator operationcycle has been extended from1.5-2months to5.3-6.4months after the optimizationoperation. The boiler efficiency could be increased by about1.5%. Finally, the projectwill bring economic profits of about RMB2,676,800, while reaching the maximizingsolution for incinerators environmental safety issues that may arise in the start andstop furnace process. |
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