PRODUCT QUALITY MULTI-OBJECTIVE DRYER DESIGN

ABSTRACT

Design of conveyor-belt dryers constitutes a mathematical programming problem involving the evaluation of appropriate structural and operational process variables so that total annual plant cost involved is optimized. The increasing need for dehydrated products of the highest quality, imposes the development of new criteria that, together with cost, determine the design rules for drying processes. Quality of dehydrated products is a complex resultant of properties characterizing the final products, where the most important one is color. Color is determined as a three-parameter resultant, whose values for products undergone drying should deviate from the corresponding ones of natural products, as little as possible. In this case, product quality dryer design is a complex multi-objective optimization problem, involving the color deviation vector as an objective function and as constraints the ones deriving from the process mathematical model. The mathematical model of the dryer was developed and the fundamental color deterioration laws were determined for the drying process. Non-preference multi-criteria optimization methods were used and the Pareto-optimal set of efficient solutions was evaluated. An example covering the drying of sliced potato was included to demonstrate the performance of the design procedure, as well as the effectiveness of the proposed approach.     

PRODUCT QUALITY MULTI-OBJECTIVE OPTIMIZATION OF FLUIDIZED BED DRYERS

Design of fluidized bed dryers constitutes a mathematical programming problem involving the evaluation of appropriate structural and operational process variables so that total annual plant cost involved is optimized. The increasing need for dehydrated products of the highest quality, imposes the development of new criteria that, together with cost, determine the design rules for drying processes. Quality of dehydrated products is a complex resultant of properties characterizing the final products, where the most important one is color. Color is determined as a three-parameter resultant, whose values for products undergone drying should deviate from the corresponding ones of natural products, as little as possible. In this case, product quality dryer design is a complex multi-objective optimization problem, involving the color deviation vector as an objective function and as constraints the ones deriving from the process mathematical model. The mathematical model of the dryer was developed and the fundamental color deterioration laws were determined for the drying process. Non-preference multi-criteria optimization methods were used and the Pareto-optimal set of efficient solutions was evaluated. An example covering the drying of sliced potato was included to demonstrate the performance of the design procedure, as well as the effectiveness of the proposed approach.     

PRODUCT QUALITY MULTI-OBJECTIVE OPTIMIZATION OF FLUIDIZED BED DRYERS

ABSTRACT

Design of fluidized bed dryers constitutes a mathematical programming problem involving the evaluation of appropriate structural and operational process variables so that total annual plant cost involved is optimized. The increasing need for dehydrated products of the highest quality, imposes the development of new criteria that, together with cost, determine the design rules for drying processes. Quality of dehydrated products is a complex resultant of properties characterizing the final products, where the most important one is color. Color is determined as a three-parameter resultant, whose values for products undergone drying should deviate from the corresponding ones of natural products, as little as possible. In this case, product quality dryer design is a complex multi-objective optimization problem, involving the color deviation vector as an objective function and as constraints the ones deriving from the process mathematical model. The mathematical model of the dryer was developed and the fundamental color deterioration laws were determined for the drying process. Non-preference multi-criteria optimization methods were used and the Pareto-optimal set of efficient solutions was evaluated. An example covering the drying of sliced potato was included to demonstrate the performance of the design procedure, as well as the effectiveness of the proposed approach.     

喷雾干燥设备设计的数学模拟法

系统论述了喷雾干燥器内粒子的运动状态与风场流动特性及其数学模型的建立过程,在传递理论的基础上根据马歇尔方程计算了干燥过程中粒子与干燥介质之间的传质传热,通过求解粒子在干燥室内的运动方程而进行喷雾干燥设备设计的粒子运动轨迹法及设计计算程序的计算机实现过程,并用实验数据及理论解对程序的可靠性进行了论证。     

注塑件的品质管理技巧

从注塑机、塑料原料、成型模具、人员等多方面,结合公司实际,系统论述了注塑件品质管理的主要内容和方法,可供其他注塑企业搞好注塑生产和管理、提高产品品质参考。     

成品尿素包装质量的控制

根据生产实际概括和总结成品尿素包装质量的控制过程,提出质量控制的关键环节和控制点,对尿素包装质量进行有效控制.     

塑料成型加工讲座(第六讲) 注塑成型制品的质量控制

讨论了影响注塑制品外观、尺寸精度以及产品的物性等成型质量的主要因素,从注射机、模具、成型工艺、制品设计等方面提出了相应的改进措施。     

QUALITY INTERACTION IN A JET SPOUTED BED DRYER FOR BIO-PRODUCTS

An experimental study was conducted to apply the jet spouted bed (JSB) dryer with inert bodies for drying of fodder antibiotic; (zinc-salt bacitracin and tylosin) and baker's yeast which are extracted from fermentation broth. After establishing the drving properties of these products (e.g. sorption isotherm, water activity and thermostability), the influence of basic drying parameters (temperature of drying agent, bed loading, gas flow rate) on drying characteristics and quality of the products was determined. The results proved that a JSB dryer may be successfully applied to fodder antibiotics; especially to Zn-bacitracin; however, for a highly labile live organism like baker's yeast, this method cannot be used. The optimal parameters for drying of Zn-bacitracin have been presented.     

QUALITY INTERACTION IN A JET SPOUTED BED DRYER FOR BIO-PRODUCTS

ABSTRACT

An experimental study was conducted to apply the jet spouted bed (JSB) dryer with inert bodies for drying of fodder antibiotic; (zinc-salt bacitracin and tylosin) and baker's yeast which are extracted from fermentation broth. After establishing the drving properties of these products (e.g. sorption isotherm, water activity and thermostability), the influence of basic drying parameters (temperature of drying agent, bed loading, gas flow rate) on drying characteristics and quality of the products was determined. The results proved that a JSB dryer may be successfully applied to fodder antibiotics; especially to Zn-bacitracin; however, for a highly labile live organism like baker's yeast, this method cannot be used. The optimal parameters for drying of Zn-bacitracin have been presented.     

DRYER DESIGN PROJECT - A TOOL TO TEACH DRYING AND DESIGN TO UNDERGRADUATES

A summary is presented of a long teaching experiment to incorporate principles of process design in a chemical engineering science course. Students are assigned real world dryer design problems following a series of lectures clarifying the basic terminology, psychrometry and principles of drying. Selected references relevant to specific dryer design problems are also provided. The instructor and teaching assistants act as consultants to the design groups consisting of up to six students. This paper will refer to authors' recent experiences with this assignment using design of spouted bed dryers for grains as illustration.     

DESIGN AND TESTING OF A NEW SOLAR TRAY DRYER

A novel low cost tray dryer equipped with a solar air collector, a heat storage cabinet and a solar chimney is designed and tested. The design is based on energy balances and on an hourly-averaged radiation data reduction procedure for tilted surfaces. Measurements of total solar radiation on an horizontal plane, ambient temperature and humidity, air speed, temperature and relative humidity inside the dryer as well as solids moisture loss-in-weight data are employed as a means to study the performance of the dryer. First, detailed diagnostic experiments are carried out with no drying material on the trays. Next, a number of experiments is conducted using a controlled reference material whose reproducible dehydration pattern allows comparisons among runs. Drying is also tested during night operation and under adverse weather conditions. For all the employed conditions, the material gets completely dehydrated at a satisfactory rate and with an encouraging system's efficiency.     

SOME CRITERIA OF SPRAY DRYER DESIGN FOR FOOD LIQUID

Spray drying has many applications for a wide variety of dried food powders. The quality of spray dried food is quite dependent on the atomization characteristics and the heat and mass transfer on drops inside the spray dryer. This paper deals with some design criteria of the spray dryer such as the atomizer, the drop trajectory and the heat/mass transfer between the drop and the drying air.     

SOME CRITERIA OF SPRAY DRYER DESIGN FOR FOOD LIQUID

Abstract

Spray drying has many applications for a wide variety of dried food powders. The quality of spray dried food is quite dependent on the atomization characteristics and the heat and mass transfer on drops inside the spray dryer. This paper deals with some design criteria of the spray dryer such as the atomizer, the drop trajectory and the heat/mass transfer between the drop and the drying air.     

DRYING CHARACTERISTICS AND PRODUCT QUALITY OF OKRA

ABSTRACT

Effects of size (whole and sliced), pre-treatment (blanching in water and 0.5% NaCl solution at 95° C) and temperature of drying air (40, 55 and 70° C) on the drying characteristics and quality of okra were studied. Estimation of the drying rate established that the drying of okra takes place under the falling rate period. Page's model was found to adequately describe the drying behavior of okra over a wide range of drying conditions used in the study. The coefficients of Page's model were correlated with air temperature and it was found that the dependence of the rate constant on the drying air temperature can be described using the Arrhenius law. The quality of the dried product was found to be best when okra was sliced and blanched at 95° C in 0.5% NaCl solution for 5 min and then dried at 55° C.     

DRYER DESIGN PROJECT - A TOOL TO TEACH DRYING AND DESIGN TO UNDERGRADUATES

A summary is presented of a long teaching experiment to incorporate principles of process design in a chemical engineering science course. Students are assigned real world dryer design problems following a series of lectures clarifying the basic terminology, psychrometry and principles of drying. Selected references relevant to specific dryer design problems are also provided. The instructor and teaching assistants act as consultants to the design groups consisting of up to six students. This paper will refer to authors' recent experiences with this assignment using design of spouted bed dryers for grains as illustration.     

日用陶瓷造型的“非主流”设计

社会经济的快速发展与物资的日益丰富使得日用陶瓷的消费市场日趋壮大,各类陶瓷用品层出不穷。日用陶瓷造型的非主流设计以非主流群体个性表达为思路,试图从陶瓷产品的用色、用形、用材、用功上别出心裁,以另类的设计突破主流与传统,拓展日用陶瓷的创意设计。     

基于正交试验和Moldflow的注塑制品表面质量成型工艺优化设计

以手机电池盖为例,采用正交试验法和Moldflow仿真模拟相结合,研究了不同成型工艺参数对注塑制品翘曲量以及缩痕指数的影响,并通过对试验数据的分析处理,得到优化的成型工艺参数,从而实现了注塑工艺参数设计的优化.     

浅论短切毡机组生产线与产品质量关系

介绍了短切毡机组主要功能段设备及短切机如何均匀分散纤维,纤维通过窄条状成型室沉降成型的优点等.从短切毡生产线对产品质量的影响的角度,阐述了通过生产实践对其中的某些设备零、部件在设计及生产制造上需要加以注意及改进的地方.同时也简要提及了一些工艺参数对设备生产中所产生的影响.     

小型色母粒连续干燥装置的设计

为了解决在涤纶有色长丝生产中干燥后的色母粒在注射器料斗中又吸湿的问题,浙江涤纶厂自行设计了小型色母粒连续干燥装置.本文介绍了该装置的用途、工艺过程及设备设计的计算与控制,供有关厂家参考.     

DESIGN AND TESTING OF A COMBINED CONDUCTION-CONVECTION ROTARY PADDY DRYER

A rotary drum dryer prototype was designed, fabricated and tested to combine convection drying with conduction heating of paddy to increase moisture reduction rates. Ambient air forced inside the drum counter-flow to the direction of the cascading grains brought about “dryeration” of the hot grains, resulting in cooler grain output and increased moisture reduction rates. Its partial drying capacity doubled that of the benchmark pre-dryer at 5 rpm drum speed and quadrupled at 7 rpm, requiring only a single-pass operation. Tests using freshly harvested and re-wetted paddy showed that partial drying capacity, final moisture content and moisture reduction rate were all significantly affected by counter-flow air velocity, Its overall thermal efficiency was also 50% higher.