Biomass resources such as agricultural and forestry wastes are very rich in China. Biomass can be compressed into a pellet and used instead of coal for heating, electricity, etc. Currently, the use of biomass pellets is being rapidly promoted. Not only can they be used for home cooking, heating, they can also be used as high-quality fuel for industrial boilers and power plants. Compared with coal, the greenhouse gas emissions of biomass pellet less than 1/9 of the coal, so these pellets have environmental benefits. This thesis research is about a biomass pellet molding viscoelastic constitutive model. The six kinds of biomass pellet raw materials which include corn straw, peanut shell, wheat straw, soybean straw, cotton straw and sawdust were the study objects densified by a 485 type roll pellet mill to analyze the stress change rules during the densifying process and measure the single feedstock of a biomass pellet by microscope in this paper. The densifying process of biomass pellets after feedstock was simulated and studied through a universal testing machine and self-made compress fixture when this is no raw material feed. The constitutive model was built for biomass pellets with viscoelastic theory to present the densifying mechanism for biomass pellets from the standpoint of mechanics, and the maximum stress and the energy consumption of the densifying process of the different species of raw material were compared and studied. The results showed that the viscoelastic constitutive model can be used to describe the densifying process of biomass pellets. A constitutive model of stress to strain can be adopted at the densifying process phase, and stress to time at stress relaxation phase. The fitting of a model curve is perfect and all coefficients of association are higher than 90%. Basically, the single feedstock for different raw material is the same, which is approximate 150 to 160 mg, while the densifying pellet density varies from each other which can be 1030, 1170, 1010, 1060, 1185, 1240 kg/m³for corn straw, peanut shell, wheat straw, soybean straw, cotton straw and sawdust respectively. The maximum stress for the six kinds of raw material is that cotton straw and sawdust is higher, approximately 67 to 77 MPa, and the other 4 are between 45 and 55 MPa. The energy consumption of sawdust is the highest, which is 158 J/g, followed by cotton straw 91.4 J/g, peanut shell 86.9 J/g and soybean straw 65.5 J/g, and wheat straw and corn straw is much lower, which is 56.2 J/g and 45.1 J/g respectively. The biomass pellets’ density is higher, and the energy consumption is higher which can be increased as fast as the increasing of density. This study results provide an important theoretical basis to solve the problem of the high-energy consumption of biomass pellets densifying manufacture, and ease the wear and short life of the key components of pellet mills.% 为研究生物质颗粒成型燃料压缩成型机理，该文用玉米秸秆、花生壳、小麦秸秆、大豆秸秆、棉花秸秆、木屑等6种生物质原料，采用生物质颗粒燃料成型机进行压缩成型，研究生物质颗粒燃料压缩成型过程，采用黏弹性理论，建立生物质颗粒成型燃料的本构模型，从力学角度提出生物质颗粒成型燃料的压缩成型机理，并研究对比不同种类生物质原料压缩的最大应力与能耗。结果表明，6种生物质原料中棉杆和木屑的最大应力较高，其余4种原料略低；木屑的压缩能耗最高，其次为棉秆、花生壳和豆秸，小麦秸秆和玉米秸秆较小。该研究结论为解决生物质颗粒成型燃料成型加工能耗高，关键部件受力磨损导致寿命低等问题提供一定参考。
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