LIU Jiali;WANG Zhichao;DENG Fengjiao;TU Jingyi;FANG Shunli;Xi'an Thermal Power Research Institute Co.,Ltd.;Xi'an Yitong Thermal Technology Services Co.,Ltd.;In order to improve the safety and economy of the direct blending biomass in large pulverized coal boilers,the differences of coal quality and combustion performance between typical biomass and coals were analyzed,and the influence of biomass blending on equipment adaptability and operation of main and auxiliary boilers was discussed comprehensively in this paper. Meanwhile,typical combustion modes and characteristics of directly blending biomass at home and abroad were comprehensively studied. The results show that the biomass had the advantages of high moisture,low density,high Vdafand oxygen,low sulfur,which has excellent environmental protection performance.When the large-scale pulverized coal-fired boiler is mixed with biomass,the influence on operation and the adaptability with auxiliary equipment need to be considered,especially the total moisture,calorific value,ash melting temperature,alkaline oxides such as Fe2 O3,Ca O,MgO and K2 O in ash composition on fuel preparation,storage and transportation,boiler efficiency,output of pulverizing system,load capacity and boiler slagging,fouling and corrosion and so on. Generally,the blending 5%-10% formed biomass has no significant impact on the operation of the boiler,combustion system,pulverizing system and other auxiliary systems,through the optimization of biomass types. Considering the technical feasibility,economy and operation safety,it is more economical to adopt independent combustion process2,i.e. to use the standby pulverizing system of boilers to realize the independent combustion of biomass. In order to prevent burning-out of biomass burner,it is required that the inlet air temperature of biomass mill should be less than 100 ℃ to ensure the primary air temperature of the mill outlet lower than 50 ℃,and 40-45 ℃ is appropriate. The co-grinding blending process can be considered when the biomass ratio is low or the blending time is short,but the spontaneous combustion of biomass needs to be controlled strictly to ensure the safety of biomass blending. Therefore,the safe operation of large-scale pulverized coal power plant boilers when blending directly with biomass can be guaranteed by optimizing the types of biomass,appropriate blending mode,blending proportion control and optimization of operation parameters. Blending biomass directly on large capacity and high parameter pulverized coal boilers has the advantages of less investment,less area covered,less or zero equipment modification,high thermal efficiency and no seasonal influence,while the main reason that restricts its large-scale application is the precisely measurement without human involvement at present.
2019 05 v.25;No.123 [Abstract][OnlineView][HTML全文][Download 1372K]