| Carbon spheres is a new type of carbon material and has a wide range of applications.Its synthesis methods and synthetic raw materials are various.Biomass tar is a black,high-viscosity,irritating odor mixture produced during the pyrolysis and gasification of biomass.It has the characteristics of complex components,strong hazard to pyrolysis equipment and environment,and is a type of environmental pollutants.Since biomass tar contains a lot of carbon,it can be used as a carbon source for preparing carbon materials.In this project,biomass tar is used as carbon source,and the carbon nanosphere material is prepared at a relatively low temperature and pressure using the carbonization of concentrated sulfuric acid which provides a new idea for the treatment and recycling of biomass tar and a new method for the preparation of carbon nanospheres has been explored.The selected raw biomass tar was pretreated and refined,and its components were analyzed qualitatively and quantitatively at the same time as industrial analysis.It was found that the raw biomass tar has a low moisture content(8.95%).Low ash content(0.57%),high volatility(80.9%),and high heat value(30.69 MJ/kg).The main component of this biomass tar is phenols,with a relative percentage of 39.09%,especially m-cresol,which is the highest,reaching 9.41%;followed by benzene and its homologues,with a relative percentage of 18.2%.The methanecresol,the most abundant component of biomass tar,was used as a characteristic pollutant.and concentrated sulfuric acid was used as a carbonizing agent to prepare carbon materials.The material was characterized and analyzed by elemental analysis,FT-IR,XRD,and SEM.The mainly element of the product is carbon(about 56%)and O(about 32%),and S(about 3%)and H(about 9%)are less abundant.The functional groups contained in the product mainly include hydroxyl group,ketone carbonyl group,benzene ring and sulfonic acid group.The product has a low degree of graphitization and is mainly present as amorphous carbon.The ideal carbon nano-particles are nanoscale,with diameters below 50 nm.The influences of reaction temperature,reaction time,raw material dosage and feed rate on the reaction products were explored and the best reaction conditions were explored.It was found that the yield,morphology and other properties of the product prepared at a temperature of 220 ℃,a reaction time of 10 minutes,a raw material of 22.5 ml(concentrated sulfuric acid 250 ml),and a feed rate of 0.5 ml/min were the best.The biomass tar refined distillation is used as raw material and the concentrated sulfuric acid is used as a carbonizer to prepare carbon materials.The elemental analysis,FT-IR,XRD,SEM and other characterization methods were used to characterize the physical and chemical properties of the prepared carbon material.The product was found to contain mainly C(about 56%)and O(about 34%)elements,as well as a small amount of S(about 7%)and H(about 3%)elements.The main functional groups contained in the product are hydroxyl,ketone carbonyl,benzene ring,sulfonic acid and ether linkages.The reaction temperature is changed to carry out experiments to explore the effect of reaction temperature on the product,and the optimal reaction temperature is 260 ℃.Multi-method characterization and industrial analysis of the products with the best reaction conditions found that the darkness reached the level of high-pigment carbon black.The biomass tar can produce spherical nano-carbon materials under the effect of concentrated sulfuric acid carbonization,and has high application potential. |
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