| Raw syngas with fly ash gasification technology can effectively reduce the combustible content of fly ash in the raw syngas,which can handle raw syngas from different types of fluidized bed gasifiers.It can realize the removal and utilization of fly ash,which has extremely high development value and important research significance.Based on this technology,a single raw syngas with fly ash gasifier adopts the co-rotating burner arrangement,and there is burner slag plugging problem during operation.In order to solve this problem,this paper proposes a multi-burner forward and reverse rotation arrangement.A gas-solid cold modeling test bed with a ratio of 1:8 to the prototype gasifier was built,and the laser doppler particle analyzer(PDA)was used to acquire flow field parameters in the gasifier furnace with the multi-burner forward and reverse rotation and the co-rotating burner arrangement.The effect of the two burner arrangements on the gas-solid flow field in the gasifier was studied.The average tangential velocity under forward and reverse rotation burner arrangement shows single crest and trough distribution on the ratio of tangential distance relative to measurement window center between burners and outer diameter of burner representing dimensionless distance(short for tangential dimensionless distance)from-1.6 to-0.48 section of burner center section.Crest area is the flow area of burner A1 jet.Trough is formed by the jet direction reversal of burner A1 after two burner jets collide and mix.On tangential dimensionless distance from-0.16 to 1.6 section,this velocity has a double crest distribution.Two crests respectively correspond to flow area of burner A2 jet and area of the swirling airflow generated by burner jets.The central recirculation zone(CRZ)area at 80% load,full load and 120% load on burner center section account for 4.76%,12.62% and 17.81% of measured section area respectively.Many particles gather in the furnace wall area.The area of CRZ at 120% load is the largest on vertical section.The average tangential velocity under co-rotating burner arrangement shows single crest distribution on tangential dimensionless distance from-0.96 to1.6 section of burner center section,crest area is the flow area of burner A2 jet.This velocity shows single crest and trough distribution on tangential dimensionless distance from-1.6 to-1.12 section,Trough is formed by jet flow of burner A2,and crest is formed by burner A2 jet injecting ambient air.The CRZ area at 80% load,full load and 120% load account for 7.53%,4.41% and 8.56% of measured section area respectively on burner center section.Particles gather in the furnace wall area obviously.There is central recirculation zone on vertical section under three loads.Due to the mutual strengthening between burner jets,he rotation intensity of flow field is larger under co-rotating burner arrangement.The flow field is formed by the superposition of the burner jets with opposite rotation directions under forward and reverse rotation burner arrangement.One of the jets flow direction will be obviously reversed after collides and mixes,making the mixing between burner jets more intense.Strengthen the heat transfer between raw syngas in fly ash gasifier,and the temperature near the nozzle of burner rises,which is conducive to the formation of liquid slag and solve the problem of burner slag plugging.The tangential average speed under co-rotating arrangement on the vertical section is greater at full load.In the near wall area,particle volume flow under co-rotating arrangement is 1.99 times that of forward and reverse rotation arrangement.In the actual operation of fly ash gasifier,more high-temperature gas-solid products are close to the wall surface,which will increase the high temperature corrosion of the refractory brick furnace wall. |
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