关于国内干燥设备的几个问题

从干燥设备的开发设计、使用、操作及适用范围４个方面论述了干燥设备中所存在的问题,旨在推动干燥行业能以理论来指导生产、使用和操作,并能提高设备的生产能力以及出现通用性强的干燥设备。     

如何选用正确的干燥设备,以适应工艺需求

<正>在干燥工序中,选用哪种干燥设备?如何正确使用干燥设备来取得最佳的干燥效果?这是干燥设备选型过程中最常见的问题。1去湿干燥     

新型干燥器在硫酸钡生产中的应用

在硫酸钡生产过程中,传统工艺采用的干燥设备是回转窑干燥器,其存在能耗高、污染环境、设备腐蚀严重等缺点.介绍了一种应用于硫酸钡干燥的新型高效节能环保型组合干燥装置--特制螺旋干燥器和特制盘式连续干燥器.阐述了新型干燥设备的工作原理及干燥工艺流程.分析了新型干燥设备应用于硫酸钡干燥过程所具有的特点,并与回转窑干燥设备在环保、节能等方面进行了比较.结果表明,在硫酸钡的干燥中,新型干燥设备热效率高,物料损失小,占地面积小,粉尘产生量极少,耗煤量小.     

化工干燥设备的材料选用及其防腐蚀措施研究

干燥处理是当前化工领域最普遍的操作之一,干燥需要依靠一定的设备与装置,不同的物料具有不同的性质,因此,对应的干燥设备也应该有所差异,这就涉及到化工干燥设备材料的选择问题,要参照实际的干燥工作来优选合适的干燥设备材质,并采用科学的安装方法,并做好设备防腐蚀工作,确保干燥设备长期使用。本文分析了化工干燥设备的材料选择方法以及防腐蚀措施。     

化工干燥设备的材料选用及其防腐蚀措施研究

当前的化工企业各生产部门中,干燥设备早已得到了普遍应用。需干燥处理的各种物料,相应有不一样的管理指标,所以,在实际生产环节中,含湿种类和产品各项指标各异,须由具体干燥设备选择相应的材料,应用所对应的安全生产制造办法。本文在提出化工干燥设备的防腐蚀措施以外,还分析化工干燥设备的材料选用。     

涤纶切片差别化干燥系统生产中问题及改善

通过对郑州中远涤纶干燥设备的分析,了解此干燥设备在干燥非涤纶或改性涤纶切片时的特点及需要进行的改善,从而使郑州中远干燥设备有更广泛的适应性,满足涤纶切片纺丝差异化的生产特点。为切片纺丝的干燥过程的工艺及设备优化提供参考。     

试论变压器器身干燥中煤油气相干燥设备的应用

变压器器身干燥过程中,采用煤油气相干燥设备具有很强的优势,通过对煤油干燥气相的参数特征进行分析,探讨了煤油气相干燥设备的应用优势,并指出了煤油气相干燥设备在具体应用过程中需要注意的问题。     

改善喷射闪蒸干燥机干燥范围的结构设计

针对目前干燥行业存在的干燥设备干燥范围有一定限制的问题,结合新出现的高效、节能干燥设备－喷射闪蒸干燥机的干燥原理,提出了在该机上采用可移动喷嘴的结构,使该设备扩大了干燥范围,能适应更多的不同物料的干燥。     

ZLG系列振动流化床干燥(冷卻)机

靖江市干燥机械厂专业生产成套干燥设备已有十多年历史。近年与科研单位合作,共同改进、设计、制造了多种干燥设备,适应性广,热效率高。1993年经工商部门批准,更名成立“江苏双飞空调干燥设备制造公司”。 ZLG系列振动流化床干燥、冷却机结构新颖,节能效果明显。已成为替代进口机,取代烘箱、固定床、沸腾床等老式干燥设备的理想设备,具有90年代初世界水平。广泛用于     

ID90干燥机

英国Interdri公司生产一系列日用陶瓷干燥机。近年来试制成功了ID90干燥机。这种干燥机最适宜于扁平制品的干燥。它具有干燥速度快(与现有干燥设备相比,干燥时间缩短到65%),热耗小(与现有干燥设备相比,燃料节省到70%),并且还具有体积小,机械结构合理,制品在干燥过程中不晃动等特点。可以     

Effect of operating parameters on the drying performance of multicylinder paper machine dryer section

The drying performance of multicylinder dryer section in a paper machine was investigated under various operating parameters: Inlet paper solid content (48–50%), inlet paper temperature (45–50°C), supply air temperature (100–90°C), and exhaust air humidity (75–85?g H₂O/kg dry air). The variation in environmental conditions was also considered. In this study, an improved static model was utilized to study the influence of these operating parameters on paper drying. The model was constructed using sequential modeling approach based on the drying techniques of multicylinder dryer section of a paper machine. The calculated paper solid content leaving each paper drying module and energy use is in agreement with the measured results. The simulation results showed that higher paper solid content and temperature entering the dryer section, lower supply air temperature, and higher exhaust air humidity were favorable for drying performance within the studied range of these parameters.     

Drying Kinetics and Antioxidant Phytochemicals Retention of Salak Fruit under Different Drying and Pretreatment Conditions

Kinetics of hot air drying and heat pump drying were studied by performing various drying trials on salak slices. Isothermal drying trials were conducted in hot air drying and heat pump drying at a temperature range of 40–90°C and 26–37°C, respectively. Intermittent drying trials were carried out in heat pump drying with two different modes: periodic heat air flow supply and step-up air temperature. It was observed that the effects of relative humidity and air velocity on drying rate were significant when moisture content in salak slices was high, whereas the effects of temperature prevailed when the moisture content was low. As such, it was proposed that drying conditions should be manipulated according to the moisture transport mechanisms at different stages of drying in order to optimize the intermittent drying and improve the product quality. Generally, loss of ascorbic acid during drying was attributed to thermal degradation and enzymatic oxidation, whereas the loss of phenolic compounds was mainly due to thermal degradation. Experimental results showed that heat pump drying with low-temperature dehumidified air not only enhanced the drying kinetics but produced a stable final product. Heat pump–dried samples retained a high concentration of ascorbic acid and total phenolic compounds when an appropriate drying mode was selected.     

旋转闪蒸干燥技术在分子筛制备中的应用与改进

介绍了旋转闪蒸干燥的原理、特点及其在分子筛干燥过程中的应用。针对生产中存在物料粘壁和堵塔等问题进行了分析。通过对设备内部结构的研究，发现风量、环隙口风速、混合室风速、空床风速、布袋除尘风速以及倒锥体尺寸的设计偏差是导致上述问题的主要原因。经过设计参数优化和设备改造，提高了物料的干燥效率，彻底解决了干燥工序中存在的诸多问题。该技术的成功实施对于旋转闪蒸干燥技术在其他化工领域的应用也有很好的借鉴作用。     

COMPUTER ANALYSIS OF INDUSTRIAL BATCH DRYER AERODYNAMICS

One of the fundamental problems encountered in the batch dryer design field is the determination of appropriate equipment configuration that would ensure uniform distribution of air over the dryer trays. Such industrial batch dryer aerodynamics problems can be successfully investigated using computational fluid dynamics techniques. A mathematical model for predicting the two-dimensional air flow inside a typical industrial batch dryer equipment is developed and analyzed. The model consists of the full set of partial differential equations that describe the conservation of mass and momentum inside the dryer. The standard k-E model is used to describe turbulence in addition to the governing conservation equations. Distribution of drying air within the dryer is regulated using adjustable air blast blades in the entrance section of the drying chamber. An appropriate configuration of these flow adjusting devices is proposed so that an adequately uniform drying air distribution pattern inside the drying chamber is achieved. Finally, a characteristic design case is presented to demonstrate the effectiveness of the proposed approach.     

COMPUTER ANALYSIS OF INDUSTRIAL BATCH DRYER AERODYNAMICS

ABSTRACT

One of the fundamental problems encountered in the batch dryer design field is the determination of appropriate equipment configuration that would ensure uniform distribution of air over the dryer trays. Such industrial batch dryer aerodynamics problems can be successfully investigated using computational fluid dynamics techniques. A mathematical model for predicting the two-dimensional air flow inside a typical industrial batch dryer equipment is developed and analyzed. The model consists of the full set of partial differential equations that describe the conservation of mass and momentum inside the dryer. The standard k-E model is used to describe turbulence in addition to the governing conservation equations. Distribution of drying air within the dryer is regulated using adjustable air blast blades in the entrance section of the drying chamber. An appropriate configuration of these flow adjusting devices is proposed so that an adequately uniform drying air distribution pattern inside the drying chamber is achieved. Finally, a characteristic design case is presented to demonstrate the effectiveness of the proposed approach.     

A Mathematical Model for Constant and Intermittent Batch Drying of Grains in a Novel Rotating Jet Spouted bed

A diffusion-bared mathdcal model is prswmed for batch drying of corn in a novel rotating jn spouted bcd device under constant as well as intermitted drying conditions. Such a device is suited for drying of large partides (e.g. grains, beam, seed, etc) for which internal heat and mass tranfer rates control the drying kinetics. Based on literature data for moisture diffusivities the model predictions are compared with experimental data for both continous and time-dependend air supply and/or heat input. Effects of dcvant parameter are evaluated and discussed in the light of potential pnrctieal applications.     

空气干燥系统的改造

分析了空气干燥系统的现状,找出了存在的隐患,提出了解决措施及对空气系统设计的建议。     

Study of Intermittent Low-Pressure Superheated Steam and Vacuum Drying of a Heat-Sensitive Material

Low-pressure superheated steam drying (LPSSD) has recently been applied to drying of various heat-sensitive foods and bioproducts with success. Several studies have shown that the quality of LPSSD-dried products is superior to that obtained using conventional hot air or vacuum drying. However, drying time and energy consumption for LPSSD is generally greater than that for vacuum drying. Therefore, it is necessary to examine different methodologies to improve the energy efficiency of LPSSD. An intermittent drying scheme is one possible method to reduce the energy consumption of the process while maintaining the desired product quality. In this study, the effect of intermittent supply of energy (through an electric heater and steam injection to the dryer) and vacuum (through the use of a vacuum pump) at various intermittency values or on:off periods (10:5, 10:10 and 10:20 min in the case of intermittent supply of energy and 5:0, 5:5, and 5:10 min in the case of intermittent supply of vacuum) at the on-period setting temperatures of 70, 80, and 90°C on the drying kinetics and heat transfer behavior of the drying samples (banana chips) was studied. The effects of these intermittent drying schemes and conditions on the quality parameters of dried banana chips; i.e., color, shrinkage, texture, and ascorbic acid retention, were also studied. Finally, the energy consumption values for intermittent LPSSD and vacuum drying were monitored through the effective (or net) drying time at various intermittent drying conditions and compared with those using continuous LPSSD and vacuum drying.     

Design and Performance Evaluation of a Solar-Assisted Biomass Drying System with Thermal Storage

A solar biomass hybrid air heating system that does not require a conventional auxiliary heater but can still provide a daily load fraction exceeding 90% and supply hot air at a steady temperature and flow rate continuously for 24 h a day has been developed. The system, which combines an unglazed transpired solar collector, rock bed, and a biomass gasifier stove with heat exchanger, was evaluated by drying chilli using air at 60°C and 90 m³/h. The chilli was dried from 76.7% moisture (w.b.) to 8.4% over 32.5 h of continuous drying. The dryer reduced the drying time by 66% compared to open sun drying and provided 91.6% load fraction during the 24-h operation. The temperature of hot air supplied was stable at 60±3°C for about 21 h during the entire drying duration.