Study On The Properties And Desulfurization Effect Of Pulping Black Liquor Briquette

As a kind of briquette technology,biomass briquette plays an important role in energy conservation,emission reduction,the utilization of biomass resources,and improvement of briquette combustion performance.Alkali pulping black liquor is a kind of biomass resource.So far,the research on the alkali black liquor compound briquette has not been systematized.In this study,the black liquor produced by wood or straw alkali pulping was added to briquette to prepare black liquor compound briquette which was burned and tested to study the forming properties of black liquor compound briquette and the mechanism of sulfur-fixing during burning.This research provide technical support for the industrial application of pulping black liquor compound briquette.(1)The results on the forming properties of black liquor compounded briquette show that the drop strength of briquettes reached about 83%,and the compressive strength of briquettes reached 620 N/ball when the amount of pregelatinized starch binder is 2 wt.%,but the addition of a small amount of the binder had little effect on the thermal stability,moisture and volatile content of briquette.Therefore,the amount of pregelatinized starch was selected to be 2 wt.%.After the addition of pulping black liquor,the mechanical strength of the briquette was enhanced,and the thermal stability became worse.Furthermore,the drop strength reached 93% when the added black liquor amount was 30 wt.%.The ash content after combustion was also increased.Generally,the addition amount of black liquor was selected to be about 30 wt.%.(2)Pulping black liquor also played a role of sulfur-fixing agent in compound briquette.Analyzing the impact of different pulping black liquor content on briquette ash and sulfur fixation rate through TG,EDS,XRD and SEM,it was concluded that theaddition of 32 wt.% black liquor is the best ratio;the optimum combustion time was determined to be 3 h and the best combustion temperature was 900 ?.The sulfur fixation rate was as high as 89% by promoting combustion time and combustion temperature.The results showed that the combustion and sulfur-fixing performance of alkali pulping black liquor compound briquette exceeded that of traditional industrial briquette.(3)Comparison of biomass briquette and black liquor composite briquette prepared by adding straw indicated that black liquor composite briquettes had better combustion effects.The combustion test of civil briquette with 32 wt.% black liquor was carried out at 900 ?,compared with no black liquor briquette.The fire point of the briquette was advanced,the combustion was more complete,and the sulfur fixation rate reached87.12%,increasing 25 percentages.High-temperature resistant briquette was obtained by adding settled sludge to black liquor composite coal,and the sulfur fixation rate of the compounded briquette at 1100 ? can reach 85% when the optimal addition amount was 5wt.%.