Biochar-based fertilizer a product of organically combination of biochar with common fertilizer. It has the advantages of high utilization rate of chemical fertilizers, improvement of the soil, reduction of the usage frequency and amount of chemical fertilizers, and low environmental pollution. Biochar-based fertilizer has become a research hotspot. Currently, biochar-based fertilizer forming equipment has a low production efficiency and forming rate, and the particles produced by the machine have low resistance of pressure and qualified rate. For solving these problems, a columnar biochar-based fertilizer forming machine based on the principle of screw extrusion was developed. The main structural parameters of the extrusion device, forming device, cutting device and other parts were determined. In order to explore the impact of the machine operating parameters on the forming effect, and select the best operation parameter combination, single factor test and orthogonal test were carried out. Single factor test results showed that there was a close relationship between the qualified rate and the matching degree of screw speed and cutting speed of the pellet shaft. The yield increased with the increase of screw speed, cutting speed of the pellet shaft and opening ratio of the orifice plate. In addition, cutting speed of the pellet shaft had little effect on hardness, while hardness was reduced with the increase of screw speed and opening ratio of the orifice plate. The orthogonal experiment results showed that for the qualified rate, the influence of cutting speed of the pellet shaft and the interaction with screw speed were very significant. For the yield, the influence of screw speed was very significant, while opening ratio of the orifice plate and cutting speed of the pellet shaft were significant. For the hardness, the influence of screw speed and opening ratio of the orifice plate were very significant. Based on the range analysis and comprehensive balance method, the optimal parameter combination of the forming test was determined. The combination was that screw speed of 45 r·min-1, cutting speed of the pellet shaft of 185 r·min-1, and opening ratio of the orifice plate of 10%. Under the condition, the qualified rate was 86%, the yield was 32.27 kg·h-1 and the hardness was 2.56 kg. Based on the best operating parameters obtained by orthogonal experiment, the performance tests of the forming machine were carried out. The forming rate of particles was 96.2%, the density of particles was 0.92 g·cm-3, and the moisture content of particles was 1.61%, all meeting the relevant forming requirements. Compared with common forming equipment, the columnar biochar-based fertilizer forming machine had certain advantages. In addition, it had a great forming performance, and the particles produced by it met forming requirements in related standards. These could provide technical support for the development of forming equipment and forming process of the biochar-based fertilizer.%生物炭基肥将生物炭和普通化肥有机地结合起来,具有化肥利用率高、可以改良土壤、减少化肥使用次数和数量、污染环境程度低等优点,已成为研究热点.针对当前生物炭基肥成型设备生产效率低、成型率低,生产出的成型颗粒抗压能力小、合格率不高的问题,研制了一种基于螺杆挤压成型原理的柱状生物炭基肥成型机,并确定了挤压装置、成型装置、切粒装置等零部件的主要结构参数.为探究机器运行参数对成型效果的影响,并选出最佳运行参数组合,安排了单因素试验和正交试验.单因素试验结果表明:合格率的大小与螺杆转速和切粒轴转速匹配程度好坏有关;螺杆转速、切粒轴转速、孔板开孔率的增大,均可使产量增加;切粒轴转速对硬度影响不大,螺杆转速和孔板开孔率的增大可使硬度减小.正交试验结果表明:对于合格率,螺杆转速与切粒轴转速的交互作用和切粒轴转速影响极显著,螺杆转速影响显著;对于产量,螺杆转速影响极显著,孔板开孔率和切粒轴转速影响显著;对于硬度,螺杆转速和孔板开孔率影响极显著.对试验结果进行极差分析,并采用综合平衡法,确定了成型试验的最佳参数组合:螺杆转速为45r·min-1,切粒轴转速为185r·min-1,孔板开孔率为10%.该条件下的合格率为86%、 产量为32.27kg·h-1、 硬度为2.56kg.并以正交试验获得的最佳运行参数为试验条件,进行了成型机性能试验.性能试验结果表明:颗粒的成型率为96.2%,颗粒的密度为0.92g·cm-3,颗粒的含水率为1.61%.本文研制的柱状生物炭基肥成型机,与常用的生物炭基肥成型设备相比有优势,且成型性能好,生产的成型颗粒符合相关标准中的成型要求,可为生物炭基肥的成型设备和成型工艺的发展提供技术支持.
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