The Densification Research And Design Of Single Plunger Biomass Forming Machine

In order to study densification of biomass,a single plunger biomass briquetting machine was designed and manufactured in this paper.The working principle of the equipment and the movement rule of the forming plunger are analyzed,the key parts designed are checked,and forming research was carried out based on the equipment.Firstly,the force of biomass materials in the forming die was analyzed,and the theoretical model of the densification pressure was established according to the force analysis.In order to verify the rationality of the model,this paper takes sawdust as the experimental material,and chooses the forming die with the aspect ratio of 2:1,2.25:1,2.5:1,2.75:1 and 3:1 to carry out the experiment and the experimental results verified the rationality of the model.According to the pressure model,the influence of each parameter in the densification pressure model was analyzed.In order to further study the relationship between various factors and index variables in the process of densification,some experiments were carried out with sawdust as the experimental raw material,die temperature,moisture content of raw materials and extrusion frequency as the experimental factors,densification pressure,radial pressure resistance,density and surface quality as index variables.Based on the experimental data,the primary and secondary relations of the influence of various factors for each index variable,as well as the optimum forming parameters corresponding to each index were obtained.Through comprehensive consideration of each index,the optimum technological parameters for densification are obtained as follows:die temperature 200 C,moisture content 14%,extrusion frequency 68 times/min.Regression analysis method was used to analyze the regression function expressions between average temperature,maximum temperature,center point temperature,densification pressure and various factors,the fitting r2 was 0.954,0.892,0.871 and 0.898,respectively.Finally,the correlation among the densification pressure,radial pressure resistance,density and surface quality of the pellet were analyzed.It was found that the correlation between the surface quality and radial pressure was very strong.