Research On Slagging Characteristics Of Guangxi Bagasse Combustion Based On Ash

As one of the important renewable energies,biomass has a similar utilization mode with traditional fossil fuel,this makes biomass has the potential to substitute fossil fuel.Guangxi is the key area of sugar cane production,thus bagasse,the by-product of sugar manufacturing,has a very considerable yield,it could be effectively used through power generation by combustion.However,when compared to coal,biomass contain much alkaline metal and other inorganic elements due to its growth needs,fuel processing and transport,these inorganic elements cause slagging phenomenon during combustion process,impacting the safety,high-efficiency and economy of power generation side.This thesis analyzes and estimates slagging characteristics of Guangxi bagasse,providing a reference for the safety of Guangxi bagasse power generation.Firstly,this thesis analyzes the basic fuel characteristic of Guangxi bagasse through approximate analysis and element analysis,then the Guangxi bagasse was made into ashes according to ASTM E1755 standards,and then the ashes were analyzed by XRF,fusion temperature test and SEM respectively,finally,the grey fixed weight clustering method(GFWCM)was adopted to estimate these bagasse ash groups comprehensively,and the main conclusions were listed as follow:(1)WW/AW did not change much of Guangxi bagasse’s HHV.Meanwhile,WW/AW raised up the volatile matter,contributing to combustion process;and WW/AW decreased the ash percentage,reducing the possibility of slagging.(2)In NW group,it has a large percentage of alkaline metal elements,element Cl makes Guangxi bagasse had high temperature corrosion towards boiler during combustion process.Compared to Guangdong bagasse,the amount of alkaline metal elements in Guangxi bagasse ashes was higher than that of Guangdong bagasse.After WW/AW,the amount of slagging problematic elements was removed dramatically,and the risk of high temperature corrosion was lowered down at same time.(3)Due to high alkaline metal amount,the fusion temperature of Guangxi bagasse was higher than that of Guangdong bagasse.After WW/AW pretreatments,the fusion temperature of Guangxi bagasse was increased significantly,reducing the slagging characteristic.(4)During the morphology analysis,many tiny particles adhering to large particles was observed in NW group,and the particle sizes were varied among particles,making the NW sample has high slagging tendency.After WW/AW pretreatments,the uniformity of particle sizes has been observed,and particle had a scattered distribution,indicating that WW/AW can lower the slagging tendency.(5)Because the single slagging-predictive indices has the disadvantage of "uncertainty",this thesis adopts the GFWCM and synthesized the indices "Silicate ratio","base to acid ratio","Silicate to aluminum ratio" and "alkaline index"to make a comprehensively estimation.Estimation results show that NW group has high slagging tendency,WW/AW group have low slagging tendency,and the estimation results were constant with the experiment analysis results.Meanwhile,the extra cost of WW was analyzed by estimation decision,indicating that the extra cost still makes the total generating cost remain in the feed-in tariff and unified price of electricity sent to grid.