Experimental Study On Slagging Characteristics Of Biomass Combustion And The Effect Of Additives

With the rapid development of society,non-renewable energy sources such as fossil fuels have gradually formed a shortage.In response to the energy crisis,the country has begun to vigorously advocate the transformation strategy of renewable energy utilization.As a substitute and supplement for conventional fossil fuels,biomass not only reduces the CO2 emissions of power plants,but also reduces the emissions of NOx and SOx to a certain extent due to the low content of N and S in biomass.However,the high content of alkali metals and alkaline earth metals in biomass can easily cause problems such as fouling and slagging on the heating surface of the boiler during the combustion process,which seriously affects the continuous and stable operation of boilers and other equipment.Fly ash is one of the main solid wastes discharged by power plants.The reasonable use of fly ash can not only solve the problem of waste disposal,but also can alleviate ash accumulation and slagging to a certain extent when used as an additive.In this paper,fly ash is used as an additive to study the effect of fly ash on ash accumulation and slagging in the biomass combustion process,thereby revealing the mechanism of ash accumulation and slagging during biomass combustion.The research content is as follows:Commissioning and trial operation of the one-dimensional furnace test bench,including checking the operating conditions of the components of the system,the ratio of air volume and gas volume,and the adjustment of stable parameters for biomass combustion.The results show that adjusting the ratio of primary air,secondary air and fuel quantity at the initial moment of the preheating stage when the furnace temperature 1 reaches 600℃ and 850℃ can greatly shorten the preheating time of the furnace,and each component works well.Taking rice husk as the research object,the ash accumulation and slagging characteristics of rice husk burning were explored.The characteristics of rice husk burning are analyzed from three aspects: macroscopic,microscopic,and phase composition.From the ash sample,it can be found that the “drawing”,“corn-like”,“sea cucumber-like”,and irregular spherical ash particles can be found through XRD phase analysis.The main influencing factors of slagging characteristics.Fly ash was selected as an additive,and the characteristics of fly ash,the addition ratio,and the influence of different sampling temperatures on ash accumulation and slagging were investigated.The results show that most of the fly ash is granular,with smooth surface,strong adsorption,and rich in Al,Si,Ca,Mg and other elements.The 1:1 addition of rice husk and fly ash intensified the process of fouling and slagging.From the SEM,we can see the molten irregular spheres,and the ash collected by the deposition probe has strong adhesion.Rice husk and fly ash can alleviate the harm caused by ash accumulation and slagging according to2:1,1.5:1.The amount of slagging collected by the deposition probe is reduced,and the degree of adhesion is reduced.From the XRD pattern analysis,it can be found that a high-melting K-Al-Si composite salt is formed,which reduces the melting and agglomeration of ash accumulation and slagging.The difference in sampling point temperature has a great influence on fouling and slagging.The amount of slagging collected by the deposition probe in the high temperature zone(850℃～1050℃)is small,and the content of alkali metals is low;the middle temperature zone(750℃～850℃)The amount of slagging collected by the deposition probe is large,and the content of alkali metal is high.Therefore,in order to better use the deposition probe to collect the alkali metals in the slag,sampling at 750°C～850°C is more appropriate.