有机肥颗粒热风干燥工艺及装备研究

发布时间：2017-12-27 04:24

本文关键词：有机肥颗粒热风干燥工艺及装备研究　出处：《中国农业大学》2017年博士论文　论文类型：学位论文

【摘要】：施用有机肥作为解决目前我国土地板结、肥力下降等问题的有效手段,已始在大部分地区推广使用。但商品有机肥加工过程中干燥环节存在技术落后、工艺陈旧、能耗高、产量低等诸多问题,严重制约我国有机肥产业的进一步发展。为优化生产工艺、创新生产设备,论文通过试验研究与仿真分析相结合的方式系统研究了有机肥颗粒的物理特性和热特性,提出了三回程转筒热风干燥工艺方法。针对该工艺中存在的关键问题,设计了组合式抄板实现有机肥颗粒在转筒中筒逆重力方向流动,进行了生产样机的设计与制造,通过试验确定了该种工艺下,样机的主要性能参数。选取张家口沃丰农业科技有限公司生产的有机肥颗粒作为原料进行试验,确定了有机肥颗粒的滚动摩擦系数与含水率的关系,不同含水率下颗粒的弹性恢复系数和最大静摩擦系数;探究了有机肥颗粒水分在不同温度和不同厚度的颗粒薄层干燥过程中的变化规律,匹配了最优干燥模型,得到有机肥颗粒干燥的活化能。通过COMSOL揭示有机肥颗粒干燥过程中内部水分变化情况,直观反映了有机肥分层失水的全过程。根据倾斜布置的三回程有机肥干燥转筒的工艺要求和颗粒在筒间的运动规律,在设备中筒内设计了一种沿筒内壁面螺旋安装的组合式抄板;组合抄板可以使颗粒离开每一枚抄板后都获得一定动能,经过一系列抄板的接力,实现颗粒在中筒内逆重力方向的"爬坡"上升,完善颗粒在三层筒体间流动的过程。选择直角举升式抄板作为内筒抄板,保证颗粒抛洒的均匀度,增加颗粒与热介质的接触面积,保证颗粒在内筒的快速失水。通过EDEM仿真分析中筒内组合式抄板结构对颗粒在筒内停留时间的影响,确定了转筒转速、转筒倾角和组合式抄板平面滑板角与停留时间的影响关系;研究了转筒倾角和平面滑板角对停留时间影响的显著性,对比试验台试验结果得到以上两因素与停留时间的数学关系,经过计算确定样机设计所用组合式抄板平面滑板角度为140°。计算得到三层筒体的设计尺寸为:内筒筒径0.70 m,内筒筒长5.5 m;中筒筒径1.10m,中筒筒长6 m;外筒筒径1.6 m,外筒筒长6.5 m;水分蒸发量为642.86 kg/h,进口湿物料质量3642.85 kg/h,绝干有机肥质量2550 kg/h,所需总热量2605977.04 kJ,所需空气流量11443.3 1m3/h;根据转筒的布置方式和运转特点,设计了一体化的支撑系统,其中有高强度挡轮、专用托轮和外盘链条式驱动系统;根据相应国标制定了设备的试验大纲,计算该设备稳定运行状态下降水幅度12.906%,干燥能力0.414 t/h,小时水分蒸发量460 kg/h,单位耗热量5033 kJ/kg,生产率为2155 kg/h。
[Abstract]:The application of organic fertilizer as an effective means to solve the problems of land consolidation and fertility decline in China has been popularized in most areas. However, there are many problems in the drying process of commercial organic fertilizer, such as backward technology, outdated technology, high energy consumption and low yield, which seriously restrict the further development of organic fertilizer industry in China. In order to optimize the production process and innovate the production equipment, the physical and thermal characteristics of organic fertilizer granules were systematically studied through experimental research and simulation analysis. A three way return cylinder hot air drying process was put forward. Aiming at the key problems in the process, a combined panel is designed to realize the movement of organic fertilizer particles in the reverse gravity direction of the drum, and the prototype is designed and manufactured. The main performance parameters of the prototype are determined through experiments. Zhangjiakou Wofeng selection of agricultural science and technology limited production of organic fertilizer particles as a raw material for the test, to determine the relationship between rolling friction coefficient and water content of organic fertilizer granules under different moisture content, particle restitution coefficient and maximum static friction coefficient; explores the changes of organic fertilizer granules in different water temperature and different thickness of the layer of particles in the drying process, the optimal drying model, organic fertilizer particle drying to obtain the activation energy. The changes of internal moisture in the drying process of organic manure were revealed by COMSOL, which directly reflected the whole process of the stratified water loss of organic manure. According to the law of motion of an inclined three return organic fertilizer drying drum process requirements and particles in the cylinder between the cylinder in the device design of a wall mounted along the spiral type of copy board copy board; combination can obtain certain kinetic energy the particles leave each one copy board, after a series of copy board relay, particles in the cylinder inverse direction of gravity "Climbing" up, improve particle flow in the three layer between the cylinder body. Choose the right lifting cylinder as the copy board copy board, to ensure the uniformity of particles shed, increase the contact area and heat medium particles, particles of the inner cylinder to ensure rapid water loss. Through EDEM simulation analysis of cylinder combination type baffle structure influences the particle residence time in the barrel, effects of rotor speed, rotor angle and plane plate combined angle and the residence time of the copy board determined the relationship; on the rotary angle and plane angle on the slide significantly influence the residence time. The mathematical relationship between the above two factors and the residence time of the contrast test results, through the calculation to determine the prototype design for angle combined copy board plane is 140 DEG skateboard. The design of size three cylinders is calculated: the inner cylinder of 0.70 m in diameter, the inner cylinder length of 5.5 m; the middle cylinder diameter 1.10M, length of 6 m in the cylinder; the outer cylinder diameter of 1.6 m, an outer tube length of 6.5 m; the evaporation capacity is 642.86 kg/h, the import of wet material quality 3642.85 kg/h, the quality of organic fertilizer 2550 kg/h, total calories 2605977.04 kJ, required air flow of 11443.3 1m3/h; according to the arrangement of the rotary drum and the operating characteristics of the integrated design support system, which has high strength, special roller wheel and outer chain drive system; according to the corresponding standard test set the outline of equipment, calculation of the stable operation of the equipment state decreased water rate of 12.906%, the drying capacity of 0.414 t/h hours, the water evaporation of 460 kg/h, 5033 kJ/kg unit energy consumption, productivity is 2155 kg/h.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ440.6

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