Surface Profile Optimization of Yankee Dryer Based on Finite Element Analysis

The deformation and stress distribution of cast iron Yankee dryer caused by outside linear load， inside steam pressure and self-gravity were calculated by numerical simulation with ANSYS software. The deformation curve of the linear load area was obtained and compared with the deformation in the actual working process. The surface profile of dryer was optimized and the deformation and stress of the optimized dryer were calculated and compared with the that of before optimization. In this paper， the method of the surface profile optimization of Yankee dryer was presented．     

桨叶-微粉干燥在纳米碳酸钙生产中的应用

纳米碳酸钙的生产过程中,干燥方式的选择是影响产品最终质量和成本的重要因素之一。本文介绍了纳米碳酸钙生产过程中的喷雾干燥、带式干燥和闪蒸干燥等几种干燥方式,重点对桨叶-微粉干燥的工艺流程、设备选型、生产特点等进行了介绍,并对几种干燥方式所存在的优缺点进行了比较。     

一种磁粉料浆干燥的新方法

通过对现有磁粉干燥方法的分析，提出了一种连续干燥磁粉的新方法。此种方法是根据磁粉料浆的特点，采用倾斜安装的螺旋输送机以及悬链式间接加热干燥机，使连续干燥粉份这－工艺过程得以实现，同时指出，用悬链式间接加风干燥机连续干燥磁粉的新方法是提高磁性材料行业整体装备水平的有效途径之一．     

Drying Efficiency of Indonesian Lignite in a Batch-Circulating Fluidized Bed Dryer

This research explores the production of low-moisture, high-rank coal using a batch-type, laboratory-scale, circulating fluidized bed to dry low-rank Indonesian coal with a high moisture content of 35 wt%. The operation was performed using air as a fluidization gas in a riser (a 4-m-tall pipe with an inner diameter of 0.04 m) at a gas velocity ranging from 2.0 to 2.7 m/s and a riser temperature of 80 to 150°C. The electric heaters were installed in the upper part of a downcomer to prevent the condensation of the evaporated moist- ure. The drying rate of the coal was investigated in terms of the inlet gas temperature, the gas velocity, and the drying time in order to determine the optimum operating conditions. Changes in the moist- ure content of the coal, before and after the experiments, were char- acterized by a proximate analysis, an ultimate analysis, the higher heating value (HHV), the lower heating value (LHV), a particle size analysis, and by the equilibrium moisture content. The results show that 70 to 80 wt% (wet basis, wb) of the total moisture can be reduced when the gas velocity of the riser is 2.0 m/s and the gas temperature is 150°C. In experiments, a simple mathematical model based on the heat and mass balances and a thin-layer drying model were simul- taneously used to predict the drying behavior of coal under the given operating conditions. The results of the model are similar to those of the experiment.     

Mathematical Modeling the Drying of Poplar Wood Particles in a Closed-Loop Triple Pass Rotary Dryer

Closed-loop drying systems are an attractive alternative to conventional drying systems because they provide a wide range of potential advantages. Consequently, type of drying process is attracting increased interest. Rotary drying of wood particles can be assumed as an incorporated process involving fluid–solid interactions and simultaneous heat and mass transfer within and between the particles. Understanding these mechanisms during rotary drying processes may result in determination of the optimum drying parameters and improved dryer design. In this study, due to the complexity and nonlinearity of the momentum, heat, and mass transfer equations, a computerized mathematical model of a closed-loop triple-pass concurrent rotary dryer was developed to simulate the drying behavior of poplar wood particles within the dryer drums. Wood particle moisture content and temperature, drying air temperature, and drying air humidity ratio along the drums lengths can be simulated using this model. The model presented in this work has been shown to successfully predict the steady-state behavior of a concurrent rotary dryer and can be used to analyze the effects of various drying process parameters on the performance of the closed-loop triple-pass rotary dryer to determine the optimum drying parameters. The model was also used to simulate the performance of industrial closed-loop rotary dryers under various operating conditions.     

Air-Drying of Seeds: A Review

Beginning with harvesting, seeds are usually subjected to a series of processes which include drying for immediate or future use. Seed quality can be influenced by several factors during drying. This article presents a review of the seed air-drying process, including mathematical models based on differential equations derived from mass and energy balances for seeds and air in fixed and moving bed dryers. The article concludes with an overview of several potential drying technologies that can be applied to seeds.     

大容量低温水溶性PVA纤维生产线的开发

简介了低温水溶性PVA纤维的性能特点、应用领域、国内现状和纺丝工艺。结合以往低温水溶性PVA纤维生产线的设备配置情况,并根据单机设备的特点和适用范围,对产能为1 800 t/a的低温水溶性PVA纤维生产线的流程进行了设计。重点对该生产线上主要专用设备的工艺特点和结构特点进行了分析。指出若要进一步提高产能,纺丝机可考虑采用层叠式结构,干燥机导丝辊的支撑方式应考虑采用双支撑式结构。     

褐煤超大型直管式气流干燥装置工业生产的设计

根据褐煤高水分、易燃易爆的特点,介绍了褐煤超大型直管式气流干燥装置工业生产的设计思路,针对调试运行过程中出现的问题提出了切实可行的解决方案。     

Effectiveness of the solar biomass hybrid dryer for drying and disinfestation of maize

The Solar Biomass Hybrid Dryer (SBHD) is a new technology developed in Ghana for grain drying and utilizes biomass (agro-residues, timber scraps, etc.) along with solar drying, and is especially useful for drying during rainy periods of the year when solar drying cannot be relied on. This study assessed the effectiveness of a 5.0-MT SBHD comprising a solar tent and a furnace for thermal drying and disinfestation of maize. Mortalities of adults of Sitophilus zeamais (Motschulsky), Tribolium castaneum (Herbst) and Cryptolestes ferrugineus Stephens were assessed. Additionally, mortalities of immatures of these three species were assessed. Internal and cage temperatures (°C) in the SBHD, sun drying (SD) and laboratory (control) were monitored, as were moisture content (MC) and thermally (stress) damaged kernels (TDK) (%). During the 7-h experiment, mean internal temperatures in the SBHD, SD and laboratory were 52.3 ± 1.0 °C, 41.4 ± 0.8 °C and 30.3 ± 0.2 °C, respectively. Similarly, temperatures in cages in the SBHD (49.5 ± 1.0 °C) were higher than those for cages in the laboratory (29.9 ± 0.2 °C) and SD (38.2 ± 0.6 °C). Reduction in the moisture content of maize dried using SBHD, SD and under laboratory conditions were 7.7, 5.2 and 2.9%, respectively. This corresponded to grain MC reduction rates of 1.1%, 0.74% and 0.4% per hour. There was 100% mortality of S. zeamais and C. ferrugineus adults achieved in only the SBHD; some immatures of all three species survived in all three treatments. However, survival of immatures was highest in the laboratory, followed by SD and lowest in the SBHD for all three species. Percent TDK was higher in the SBHD (6.7 ± 0.9) than SD (3.3 ± 0.3) and laboratory (2.7 ± 0.3). These data show that the SBHD is effective for both drying and disinfestation of grain.     

催化裂化催化剂喷雾干燥过程CFD模型

基于气固两相流理论和计算流体力学（CFD）知识，结合催化裂化催化剂喷雾干燥过程的特点，运用欧拉-拉格朗日(Eulerian-Lagrangian)模型，建立喷雾干燥塔两相流CFD模型，对制备催化裂化催化剂的喷雾干燥塔内气浆两相流动量、质量和热量传递过程进行数值模拟计算。通过模拟计算结果分析，可以得到喷雾干燥塔内流速分布、温度分布以及颗粒运行轨迹等信息，从而对塔内流场信息进行可视化。将模拟结果与中型喷雾干燥塔实验数据进行对比，结果表明二者趋势一致，出口温度误差在10%以内，证明所建模型可靠，可用于喷雾干燥过程的模拟。