【作者】 董宏宇；

【导师】 吴文福； 陈晓光；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2008， 博士

【摘要】 红外辐射谷物干燥是一种高效、节能、低污染的新型谷物干燥技术。本文以遴选的Al₂O₃、SiO₂为主体原料,Fe₂O₃、CuO、Y₂O₃为辅助原料,经高温烧结合成了莫来石—铁氧体复相陶瓷,采用烧结工艺,将粉状莫来石复相陶瓷烧结在作为基体的刚玉陶瓷上,再经过球磨制粉工艺,把复合陶瓷材料制备成适合热喷涂的粉体材料,利用等离子喷涂在加热板表面制备复合陶瓷材料涂层。本文还针对自行设计的谷物干燥系统,综合考虑各种影响因素,分析了玉米红外辐射干燥的机理,建立了基于水势理论的玉米红外干燥数学模型。实验表明,使用本文研究开发的适用于谷物干燥的高发射率红外辐射陶瓷材料,能够大幅度提高谷物干燥效率,对降低谷物干燥设备能耗并提高加工谷物的品质具有重要的生产实际意义。更多还原

【Abstract】 Grain drying is one of the key links of the corn processing, it is significant influencing for quality of grain. With the development of the national economy and improvement of people’s living standard, requirements the quality of grain becomes higher and higher, regardless of grain for edible or application of deep processing. In addition to through, improved technology of agricultural production and the way of reasonable management to improve the quality of grain, by using of reasonable measures of processing and storage to ensure quality of after harvesting the grains is not serious deterioration. Research in improving the quality of grain of drying; reduce the energy consumption of drying advanced techniques, which plays a crucial role in the development of the rural economy, agriculture and the national economy.Infrared radiation is a new type of grain drying technology of efficient, energy-saving, low pollution. Infrared radiation is a process of radiation objects to spread by the way of electromagnetic waves. When the infrared radiation exposure to a object, if the frequency of the incident infrared and objects of molecule is same, the molecular material will be shown on the strong infrared absorption, the energy of be absorbed will be transformed into the thermal movement, and increase the object temperature, effect of heating and drying. High emissivity infrared ceramics material has wide range of application as one of energy saving materials. Radiation characteristic of infrared ceramics directly related to energy saving effect and drying quality of drying device. So developing a kind of high emissivity infrared ceramics material has important significance.Corn is one of the major crops in northeast region of China. By taking corn as the research object, the goal is ensure corn quality after drying and improve machining efficiency. A high emissivity infrared ceramics material fitting for grain drying was developed and was applied grain-drying device. This technique can improve grain-drying efficiency and have important practical engineering value in reducing energy consumption. This paper mainly studies the following key technologies. 1. In this paper, we were selected Al2O3, SiO2 as main precursor, Fe2O3, CuO, Y2O3 as supplementary material and mullite-ferrite ceramics were produced by high-temperature sintering. Infrared emissivity was determined at 5~15μm wave band. Formula scheme of optimum mass fraction is obtained by orthogonal design.2. Mullite powder ceramics were sintered on corundum ceramics substrate by using sintering technique. This avoids using binder and improves material service life. Compared with XRD test map and infrared properties map of samples, this paper studies the higher infrared emissivity reason of ceramics material and infrared emissivity effect of different materials and madding technique.3. We made powder material that is fit for thermal spraying using composite ceramics material by milling technology and made composite ceramics material coating using plasma-spraying technology. The results show that using heating plate of coating drying efficiency rises 15%.4. By the concept of the water potential introduced, this paper analyzed infrared drying mechanism of corn, and thought that moisture content remove force come from the difference of water potential because of the temperature grad and moisture content grad. Moisture content migrates from inside of higher water potential corn pellet to the lower water potential pellet outside, boils away within an inch of the corn pellet outside and spill over the corn pellet surface. In the same condition, compared with having not far-infrared coating, drying efficiency is higher. This is because that infrared coating emission spectrum is fit for corn absorption spectrum, and it benefits corn inner moisture content faster moving forward surface. The result is that corn is not easy to appear surface hardening and crack. In addition, drying efficiency increases as the infrared plate distance short and heating power rises.5. Based on the theoretical analyses of water potential, the mathematical model of infrared drying has been developedresult was found after the model was analyzed. are undetermined eonstants and t 15 timeinterval.6 .Infrared drying exPerimentaldevce was modifieated based on exPerimental table for grain drying, with heating plate of ceramics material. The model for infrared drying that based on the theoretical is an average moisture content model of corn pellet. Verified the model simulation results by the testing data, the value of simulating average moisture content is as consistent as the trial value; the correlation coefficient is more than 0.98.In summary, using infrared ceramics material, which is suitable for grain can, improves grain drying efficiency greatly and having important practical function in reduce energy consumption and improve the grain quality. This research results provide a technology of practical value and have greater social and economic benefits. Meanwhile, the studies can rich basic theory of grain infrared drying. It has academic significance and practical engineering value.更多还原