Study On The Thermoforming Mechanism Of Solid Fuel For Agricultural And Forestry Waste

Under the dual drive of environmental pollution and energy demand,biomass solid fuel can replace coal resources,become renewable clean energy,and gradually become the main component of the future energy development industry.The energy utilization of agricultural and forestry waste is of great significance to the expansion of biomass resources.At present,on the basis of explaining the experimental phenomenon,the thermoforming mechanism of biomass solid fuel is studied.There is no uniform guide on the molding mechanism of biomass solid fuels.In this paper,for ginkgo,oil pine,white pine and corn straw agricultural and forestry waste thermo-molding solid fuel industrialization of the practical application,in-depth study of biomass raw materialthermoforming micro-mechanism,establish the relationship between microstructure and macro nature,so that biomass solid fuel molding technology can really become a precise control,prediction and research technology,It is of great significance to speed up the conversion of biomass and enhance the economic benefits of China’s solid fuel industry.Based on the research on the thermoforming process of ginkgo,oil pine,white pine and corn straw agricultural and forestry waste,this paper analyzes the microforming mechanism of solid fuel using contact angle meter,microelectrophoresis instrμment,laser particle size analyzer and scanning electron and energy spectrometry:(1)A single-factor test of oil pine,ginkgo,white pine and corn straw was carried out,and the best parameters of the process of data analysis of agricultural and forestry waste molding were obtained through the experiment,and the effect of the agroforestry waste molding process was affected by water content,temperature,pressure and particle size.Oil-loose solid fuel moisture content in 6%,forming temperature of 90 degrees C,pressure of 90 MPa,particle size of 0.16 to 0.63 mm under the condition that oil-loose solid fuel can be formed high-quality fuel,its density,durability,break-down resistance up to 1.10 g cm-3;99.5% or more.Ginkgo solid fuel moisture content in 6%,molding temperature of 130 degrees C,pressure of 90 MPa,particle size of 0.16 to 0.63 mm,Ginkgo solid fuel can be molded high-quality fuel,its density,durability,break resistance up to 1.12 g cm-3;White pine solid fuel moisture content in 6%,forming temperature of 90 degrees C,pressure of 130 MPa,particle size of 0.63 to 1.25 mm under conditions,white skin pine solid fuel can be formed high-quality fuel,its density,durability,break-down resistance up to 1.12 g cm-3;99.75 % or more.Corn straw solid fuel moisture content of 8%,molding temperature of 110 degrees C,pressure of 130 Mpa,particle size of 0.16 to 0.63 mm under conditions,corn straw solid fuel can be formed high-quality fuel,its density,durability,resistance to falling crushing up to1.26 g cm-3;Above.(2)Using contact angle meter,electrophoresis instrμment and laser particle size analyzer,the wetting,potential characteristics and particle size distribution of oil pine,ginkgo,white pine and corn straw molding pressure blocks were carried out,and the results showed that the higher the water content of solid fuels for agricultural and forestry waste,the smaller the radon,the better the wetting.The higher the temperature,the stronger the hydrophobicity of the solid fuel,the larger the radon,the smaller the particle size,the larger the solid fuel,the lower the hydrophilic,the stronger the hydrophobic.Corn straw and white pine solid fuel is more hydrophilic,the contact angle of both materials are less than 90 degrees,oil pine,ginkgo solid fuel dredging is strong.The minimμm absolute value of the white pine potential is16.7m V,the higher the absolute value of the Ginkgo potential is 35.4 m V,and the absolute value of the oil pine and corn straw potential is in the middle,27.6 m V and 28.8 m V,respectively.From this,it can be seen that the white pine particles condense the strongest,oil pine and corn straw second,Ginkgo grain condensation is the worst.White pine material20μm particles the most,about the oil pine material 90μm particles the most,Ginkgo material60μm and 110μm particles the most,corn straw material 150μm particles the most.White pine has the highest density and durability,the most firm bonding,oil pine,ginkgo center,the density and durability of corn straw is relatively low,the bondability is not as good as oil pine,ginkgo and white skin pine.(3)The use of scanning electric mirror scanning electric mirror on oil pine,ginkgo,white pine and corn straw molding pressure section structure analysis,further demonstrate the temperature,moisture content,pressure,particle size and other different factors on the effect of solid fuel molding process of agricultural and forestry waste,that is,the lower the temperature,the higher the water content,the lower the molding pressure,The looser the solid fuel structure,the worse the physical performance,the larger the particle binding between the materials is weaker,and there are longer,wider gaps,the solid fuel molding effect is poor.When the temperature is high,it enhances the softening of cellulose and lignin and becomes a natural binder that promotes particle bonding.The proper moisture content is more firmly bonded at hot pressure.The greater the pressure,the greater the force between the particles,and the stronger the bonding of the particles.When the particle size is small,the particles fill the gap sufficiently,promoting the bonding of the particles.(4)By calculating the size of the dynamic bridge force between Van der Waal force and particles,the results show that for powder particles with the same particle size,the hydraulic bridge force between particles is tens or even hundreds of times the force between van der Waal.The size of the Van der Waal force between particles is much smaller than the liquid bridge force.Therefore,when the moisture content is high,the sμm of all adhesion forces between particles is usually estimated using the liquid bridge relay between particles.The results showed that the liquid bridge force was relatively large when the particle size was larger,of which the white pine had the largest liquid bridge force at 0.63~1.25 mm,2.49 x10-5~4.93 x 10-4N,and the corn straw had a 2.1 x 4N liquid bridge force at 0.63~1.25 mm.10-5~4.17 x 10-4N,oil pine and ginkgo in the particle size of 0.16~0.63 mm when the liquid bridge force is relatively small,but the oil pine liquid bridge force is greater than the liquid bridge force of Ginkgo,where the oil pine liquid bridge force is 1.75 x 10-5~6.88 x 10-5N,Ginkgo liquid bridge force is 6.38 x 38 x 10-8~2.51 x 10-8N.This may be due to the particle size,small gaps between fine particles,less moisture force,less hydraulic force.When the particles are relatively large,the gaps are large,the moisture force is larger,and the hydraulic bridge force is larger.