Design Of Processing Equipment Research Articles

Scale-up and control of binder agglomeration processes — Flow and stress fields

This paper describes scale-up of granulation processes where a liquid binder is added to fine powder in order to form a granular product, with emphasis on the use of specific energy (energy per unit mass) as a controlling process group. The energy input is the result of applied shear in the flow field of the process, where both stress and flow fields may be coupled with the instantaneous material properties. This analysis can be relevant to both batch and continuous processes; indeed, the use of small batch experiments can be a means to derive empirical control functions and scale-up relations for larger batch and continuous processes. The technical goal of scale-up is to maintain similarity of critical product attributes as the production scale and/or throughput of a manufacturing process is increased. In this paper, a scaling framework is developed to consider critical process transformations in relation to the desired product attributes. A similar approach can be taken in developing process control strategies. In any agglomeration process, transformations can be used to describe how raw materials (typically fine powders and liquid binders) are converted into a granular product. While critical product attributes may be characterized on the scale of individual granules (e.g., size, shape, porosity, mechanical strength, etc.), industrial scale-up requires predictive relations for the sizing, design and operation of larger-scale process equipment. Considering scale-up on the basis of transformations is one way to link the macro-scale equipment decisions with micro-scale product attributes. This approach can be applied to the scale-up of batch and/or continuous granulation processes as well as transitioning from small batch prototypes to continuous production circuits. Additionally, a framework for the description and analysis of continuum flow and stress fields in mixer-granulators and the implications for scale-up of granulation processes are discussed.

A mixed formulation for stress analysis of curved pipes with tangent terminations under in-plane forces

Curved pipes connected to tangent terminations play an important role in process equipment design for fluid transport. These structures allow changes in flow direction and simultaneously contribute to increasing the flexibility of the entire structure. The stress analysis of curved pipes (or pipe elbows) is an essential step in the design of a piping systems project. The method of hybrid formulation of shell parameters (internal forces and displacements) is an alternative to the irreducible formulation, which deals with a totally assumed displacement field for the unknowns. The main advantage of the proposed method lies in the use of lower order formulations for the differential equations used to set-up the solution as compared with the irreducible formulation. The hybrid solution here is based on a semi-analytic formulation, where the definition of the shell forces and displacements combines analytic and trigonometric functions. Tests for the most common loading cases are analysed and results for stress distribution are discussed.

RHEOLOGICAL PROPERTIES OF CORIANDER AND MINT LEAF PUREE

ABSTRACT Rheological behavior of coriander and mint leaf puree was determined at temperatures of 30 to 80C. Applicability of various rheological models available in the literature was evaluated. The Herschel–Bulkley model provided a good description of the flow behavior of coriander and mint leaf puree over the temperature range of 30–80C. The Arrhenius model successfully described the effect of temperature on consistency index of coriander and mint puree. The temperature dependence of apparent viscosity of mint puree however did not obey the Arrhenius model. The activation energy of flow for coriander and mint puree was 23.99 and 32.62 kJ/mol, respectively.PRACTICAL APPLICATIONSFlow properties of foods are determined for a number of purposes, such as quality control, understanding the structure, process engineering applications and correlation with sensory evaluation (Cepeda et al. 2002; Nindo et al. 2005). Knowledge of the rheology of suspensions contributes to a better understanding of the underlying mechanisms of momentum and heat transfer process (Telis‐Romero et al. 1999; Nindo et al. 2005). Rheological properties are also important for the design of related processing systems, including filling in bottles/cans and appropriate piping arrangements (Steffe 1992; Bhattacharya 1999). Krokida et al. (2001) recently assembled additional data on rheological properties of fruit and vegetable puree. Limited information is available in the literature on the rheological characteristics of herb purees. Herbal purees vary widely in their rheological characteristics and it is necessary to investigate each product separately. Results of this study would be useful in the quality control and design of processing equipment for processing coriander‐ and mint‐based products.

Effect of Moisture Content on Some Physical and Mechanical Properties of Sira Bean Grains

Some physical and mechanical properties of sira bean grains were determined as a function of moisture content in the range of 11.36% to 24.53% dry basis (d.b.) to provide information for the design of harvesting, handling, processing, and storage equipment and facilities. The average length, width, and thickness were 6.90 mm, 11.65 mm, and 5.39 mm, respectively, at 11.36% d.b. moisture content. The arithmetic and geometric mean diameters increased 7.01% and 7.67%, respectively, while the sphericity increased 3.07% in the moisture range from 11.36% to 24.53% d.b. Studies on rewetted sira bean grains showed that the thousand-grain mass increased 26.04%, the projected area 26.51%, the true density 10.54%, the porosity from 29.60% to 44.50%, and the terminal velocity 20.96%, while the bulk density decreased from 700.5 to 610.5 kg m-3 with an increase in the moisture content range of 11.36% to 24.53% d.b. The static coefficient of friction of sira bean grains increased linearly for six structural materials, namely, rubber (21.05%), aluminum (19.02%), stainless steel (18.03%), galvanized iron (27.59%), glass (22.38%), and MDF (medium-density fiberboard) (25.08%) as the moisture content increased from 11.36% to 24.53% d.b. The shelling resistance of sira beans decreased as the moisture content increased to 34.07%.

1116 電解コンデンサの熱解析モデル化検討のためのベンチマーク実験(J08-3 電子情報機器,電子デバイスの強度・信頼性評価と熱制御(3) 基板・部品の特性評価,ジョイントセッション,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

In the design process of electronic equipment, the early estimation of component temperature is of great importance. In order to predict the lifetime of equipments, the electrolytic capacitor is one of the most important components in thermal analysis of electronic equipment. To predict the component and system temperature, the thermal flow simulation technique has been applying to thermal design in the development phase of electronic equipment. In this study, we investigate the compact thermal modeling method of electrolytic capacitors. This paper describes the result of experiment of the confirmation of the main thermal path of the electrolytic capacitor on the printed circuit board as the basic data for the investigation of modeling method. In addition, based on the result of the experiment, we considered the benchmark experiment procedure.

Economic application of virtual commissioning to mechatronic production systems

The interaction of heterogenous control hard and software plays a key role in enabling mechatronic production systems to become flexible and agile systems. Nevertheless, control software engineering still tends to be the last step within the development process. To a large extent it is carried out during the commissioning phase of the production ramp-up. On the first hand this leads to a loss of time and quality as well as to a loss of reputation and future orders on the second hand. A method that is referred to as Virtual Commissioning tries to overcome this situation. The aim is to enable control software engineering to, both take over the initiative in system design and to perform important activities earlier in the design process of production equipment. In this paper, the technological and economical scalability of Virtual Commissioning is analyzed. Based on the analysis, a technical concept for a scalable simulation environment is presented. The paper concludes with a new method for the economic application of Virtual Commissioning.

Friction coefficient of maize, cowpea and groundnuts on different structural surfaces

The coefficient of friction of food grains and seeds which are necessary for the design of equipment for handling, transport, processing and storage of ‘mamaba', ‘asetenapa' and ‘chinese' varieties of maize, cowpea and groundnut respectively have been evaluated as a function of grain moisture content varying from 10% to 28% (wb). In this moisture range, the coefficient of friction increased from 0.223 to 0.674. There was an increase in the coefficient of friction from 0.223 to 0.453 for ‘asetenapa' variety, 0.260 to 0.522 for ‘mamaba' variety and 0.288 to 0.577 for ‘chinese' variety on rubber surface in the moisture content range of 10% to 28% (wb). Also on galvanized steel at the moisture content range of 10% to 28 %( wb), the coefficient of friction increased for ‘asetenapa' variety from 0.259 to 0.498, ‘mamaba' variety from 0.284 to 0.558 and ‘chinese' variety from 0.309 to 0.619 and on plywood, ‘asetenapa' variety had coefficient of friction increasing from 0.279 to 0.579, ‘mamaba' variety 0.311 to 0.624 and for ‘chinese' variety from 0.356 to 0.674. ‘Chinese' variety of groundnuts had the highest coefficient of friction on all the three surfaces studied with values ranging between 0.288 and 0.674 as against values of 0.223 to 0.579 for ‘asetenapa' variety which had the lowest values. Moisture effects on the coefficient of friction for the products studied were highly significant at 1%. From the study it can be said that product specification is necessary in the selection of materials for the construction of handling systems, dryers and silos.Journal of Science and Technology(Ghana) Vol. 27 (1) 2007: pp. 142-149

Engineering and Production Technology for Lightweight Ship Structures, Part II: Distortion Mitigation Technique and Implementation

Shipboard applications of lightweight structures have increased over recent years in both military and commercial vessels. Thin steel reduces topside weight, enhances mission capability, and improves performance and vessel stability, but the propensity of buckling distortion has increased significantly. At present, several US Navy construction programs are experiencing high rates of buckling distortion on thin steel structures. The standard shipyard practice of fabricating stiffened steel panels by arc welding is one of the major contributors to this distortion. Correcting the distortion is a necessary but time-consuming operation that adds no value and ultimately tends to degrade the quality of the ship structure. With a major initiative funded by the US Navy, Northrop Grumman Ship Systems (NGSS) has undertaken a comprehensive assessment of lightweight structure fabrication technology since 2002. Through collaborative research, significant progress has been achieved in the development of distortion-control techniques. Reverse arching, transient thermal tensioning (TTT), stiffener assembly sequencing, and other preferred manufacturing techniques were developed at NGSS to reduce distortion and eliminate the high rework costs associated with correcting that distortion. Complex lightweight panel structures, which are reinforced by long slender stiffeners along with numerous cutouts and inserts, pose a major challenge for distortion control. The geometric complexity yields a more complicated buckling behavior, which drives the need to develop a more fine-tuned finite element model to determine critical parameters and heating patterns for the TTT process. NGSS has recently teamed with Edison Welding Institute (EWI), Battelle Memorial Institute, and the University of New Orleans on a Navy project to further refine TTT procedures for complex lightweight ship structures. In this paper, functional requirements and the design of TTT process and production equipment are discussed. The refined TTT process will be benchmarked by the test panel observations, and a laser scanning device, LIDAR, will be used to analyze panel distortion topography.

Insight into Theories of Heat and Mass Transfer at the Solid−Fluid Interface Using Direct Numerical Simulation and Large Eddy Simulation

Solid−fluid heat-transfer coefficients have an important role in the design of chemical processing equipment. The major resistance to heat transfer lies in a region very close to the wall, where experimental measurements are very difficult. The validity and accuracy of the models developed for the estimation of the heat- and mass-transfer coefficient still do not have general applicability for the entire range of Reynolds and Prandtl numbers, because of the limited knowledge of near-wall turbulence. There have been two approaches for such model development: one is an analytical approach, which considers the momentum, mass, and heat transfer to be analogous in nature and the understanding of one of these processes can be used to predict the other two; the other approach is heuristic, based on the visualization of the behavior of the coherent structures in the near-wall region. The continuous movement of fluid elements to and away from the wall (coherent structures) affects the transport phenomena. The models for the quantification of this behavior have been developed for the estimation of heat- and mass-transfer rates in the literature. However, both these approaches contain parameters fitted empirically to obtain good agreement with the experimental heat- and mass-transfer data. These models must be tested for their formulation and empirical constants on the basis of accurate solutions of governing equations of heat, mass, and momentum transfer. This is possible using direct numerical simulation (DNS) and large eddy simulation (LES), which can accurately predict the near-wall flow pattern. An attempt has been made to exploit the ability of DNS and LES to develop insight into hitherto used models, based on analogies and/or heuristic arguments.

Evaluation of Thermal Properties of Food Materials at High Pressures Using a Dual‐Needle Line‐Heat‐Source Method

Thermal properties of food systems at high pressure (HP) are important in the design and operation of HP processing equipment. Available techniques for thermal property evaluation under HP conditions are still very limited. In this study, a dual-needle line-heat-source (DNL) device was installed in an HP vessel to evaluate thermal conductivity (k), diffusivity (alpha), and volumetric heat capacity (C(pV)) of foods at high pressure. The DNL probe was calibrated using glycerin (0.1 MPa) and 2% (w/w) agar gel (0.1 to 350 MPa) at 5 and 25 degrees C. Calibration results showed a good correlation with the reference data of pure water: R(2)= 0.966 for thermal conductivity and R(2)= 0.837 for diffusivity, and a small standard deviation of relative error (3.18%) for the volumetric heat capacity. Fresh potato and cheddar cheese were used as test samples at 5 degrees C at selected pressure levels (0.1 to 350 MPa). The potato samples gave thermal properties very close to those of pure water, but much higher than those of the cheese. The k and alpha values of both potato and cheese increased with pressure and a 2nd-order polynomial well fitted their pressure dependency. The volumetric heat capacity data did not show a clear pressure-dependency trend. The experimental system worked well for the evaluation of thermal properties at pressures up to 350 MPa.

Some physical, pomological and nutritional properties of kiwifruit cv. Hayward

In this research, several physical, pomological and nutritional properties that are important for the design of equipments for harvesting, processing, transportation, sorting, separation and packaging of kiwifruit cv. Hayward grown in the Black Sea region of Turkey were determined. The fruit characteristics ranged from 72.28g for average fruit weight, 59.41, 46.28 and 42.87mm for fruit length, width and thickness, 49.03mm for the geometric mean diameter, 0.825% for sphericity and 66.52cm3 for the volume of fruit, respectively. The bulk density, fruit density and porosity were determined as 575.27kg/m3, 1,093kg/m3 and 47.13%. The highest coefficient of static friction was obtained on plywood as 0.190, followed by polyethylene, rubber and galvanized steel sheet as 0.173, 0.163 and 0.158, respectively. The total soluble solid content, acidity, vitamin C, ash and total nitrogen content of kiwifruit cv. Hayward were 7.32%, 1.64%, 108mg/100g, 0.71g/100g and 0.84%, respectively. The fresh fruits have 1.09mg/100g total chlorophylls and flesh color data represented as L, a and b were 57.18, 17.25 and 37.46, respectively.

Some Physical Properties of Gilaburu Seed

In this study, the physical properties of gilaburu (Viburnum opulus L.) seed have been investigated. The average length, width, thickness and geometric mean diameter values in 54% of moisture content of gilaburu seed were between 6.56 and 8.44 mm, 6.24 and 8.57 mm, 1.62 and 2.52 mm, 4.19 and 5.31 mm, respectively. Sphericity, surface area, thousand seed mass and terminal velocity values in the same moisture content increased from 0.59 to 0.68, from 55.22 to 88.65 mm 2 , from 75.00 to 78.30 kg, from 4.52 to 5.15 m s -1 ; the bulk density, true density, porosity and angle of repose values changed betweeen 524.82 and 546.81 kg m -3 , 981.45 and 1046.15 kg m -3 , % 45.46 and 50.14%, 22.60 o and 26.78 o , respectively. The physical properties of gilaburu seed are necessary for the design of equipments for planting, harvesting, seperating,transporting, storage and other processing.

Passivation of stainless steel

This paper, the 18th in a series of articles on the hygienic design of food processing equipment published in TIFS, introduces the first joint EHEDG/3-A Update article in the series, a set of guidelines for the hygienic passivation of stainless steel surfaces intended for food-contact use. These guidelines have been prepared on behalf of the US-based 3-A Steering Committee and the Sanitary Standards Sub-committee of the Dairy Industry/Farm Industry Committee, in addition to the European Hygienic Equipment Design Group (EHEDG).

1917 電解コンデンサの熱解析モデル化手法の検討(J16-2 電子情報機器,電子デバイスの熱制御と強度・信頼性評価(2),J16 電子情報機器,電子デバイスの熱制御と強度・信頼性評価)

In the design process of electronic equipment, the early estimation of component temperature is of great importance. In order to predict the lifetime of equipments, the electrolytic capacitor is one of the most important componts in thermal analysis of electronic equipment. To predict the component and system temperature, the thermal flow simulation technique has been applying to thermal design in the development phase of electronic equipment. In this study, we investigate the compact thermal modeling method of electrolytic capacitors. This paper describes the result of experiment of the confirmation of the main thermal path of the electrolytic capacitor on the printed circuit board as the basic data for the investigation of modeling method.

Polyester-Based Chemically Prepared Toner for High-Speed Digital Production Printing

Recently, chemically prepared toners (CPTs) have been finding their way into an increasing number of electrophotographic printers. Although all these printers claim to utilize CPT as marking particles, the toner composition and manufacturing method used can be very different from each other. The production of conventional melt pulverized toners (MPTs) essentially consists of melt compounding and a pulverization operation of toner ingredients using standard equipment and processes that are similar for most suppliers. Different CPT manufacturers, on the other hand, produce the chemically prepared toners via entirely different approaches. The chemical methods of manufacturing include: suspension polymerization, emulsion aggregation, solvent dispersion, and the like. Each method used in the production of chemically prepared toner has its associated limitations and advantages.Use of polyester as the toner polymer is often desired because of the inherent advantages offered by these resins over styreneacrylate copolymers. Polyester binders provide a unique melt flow and mechanical toughness that is highly desirable in high-speed digital printing applications. These resins are also more suited for digital printing because of their charging behavior.The CPT process developed at Eastman Kodak Company offers the flexibility of using any soluble polymer as a toner resin or the use of monomers that are suitable for additional polymerization for making linear or crosslinked toners. With this solvent-based process, it is possible to prepare chemical toners that are based on polyester binders, which are uniquely desired in production printing. This manufacturing process is suitable for making chemically prepared toners that have the narrowest particle size distribution in the industry. Shape control is very extensive using this approach, and particle shapes ranging from completely spherical to raisin-like can be prepared easily. The degree of irregularity can be controlled to produce particles that provide optimum performance in the machine. There is a considerable amount of flexibility offered by this solvent-based process. Toner ingredients that are affected or changed by elevated temperatures can be easily incorporated into toners because this toner manufacturing process does not require any heating. This process can be used to tailor-make toners that simplify the equipment design and electrophotographic process to provide a consistent performance in producing high image quality and lower costs for printing.

Standardization of Mass Transfer Measurements: A Basis for the Description of Absorption Processes

Inaccurate mass transfer measurements may lead to an erroneous design of process equipment, since the accuracy of process modelling strongly depends on the quality of the model parameters. While procedures for measuring model parameters have been standardized for distillation, a standard for absorption has not been established yet. Thus the accuracy to predict the effective interfacial area and the mass transfer coefficients in the gas and liquid phase for several column internals varies significantly and the compatibility of data from different sources is limited. Therefore, a procedure to determine these mass transfer parameters is presented in this paper that includes guidelines for the choice of system, the experimental setup and procedure as well as the processing of experimental data. The procedure has been tested for classic and modern random packing types and results of absorption experiments are shown for a 25 mm Pall-Ring. A comparison of the experimental data with existing data and theoretical calculations from existing mass transfer correlations is presented. This comparison reveals not only discrepancies between the experimental and literature data but also the inconsistency of different sources and thus strongly supports the demand for a standardized procedure to determine mass transfer parameters for absorption systems.

Factors contributing to the poor bulk behavior of meat and bone meal and methods for improving these behaviors

Meat and bone meal (MBM), a product of the rendering industry, is a potential feedstock for numerous bio-based applications. Design of processing equipment for MBM is difficult due to MBM’s bulk behaviors; it flows less easily than many other granular materials, and it tends to foul the surfaces of processing equipment. This study examines the major factors contributing to MBM’s poor bulk behavior, including moisture content, fat content, particle size distribution and temperature, and the relative importance of these factors. Potential methods for improving MBM’s bulk properties, including use of an anti-caking agent, dehydration, fat extraction, milling and refrigeration are also studied. The effects of these factors were determined by a standard laboratory measurement, the Hausner ratio, as well as by the rate of surface-fouling and dust generation using a pilot-scale aspirator. In contrast to past studies with other granular materials, moisture content was shown to have an insignificant effect on MBM’s bulk behavior. The results, however, show that MBM fat content is a major determinant of the bulk behavior of the MBM. Reduction of fat content resulted in major changes in MBM’s bulk behavior, by all measures used. Less dramatic changes were achieved through refrigeration to solidify the fat and/or treatment with an anti-caking agent.

Process engineering design of pathological waste incinerator with an integrated combustion gases treatment unit

Management of medical wastes generated at different hospitals in Egypt is considered a highly serious problem. The sources and quantities of regulated medical wastes have been thoroughly surveyed and estimated (75 t/day from governmental hospitals in Cairo). From the collected data it was concluded that the most appropriate incinerator capacity is 150 kg/h. The objective of this work is to develop the process engineering design of an integrated unit, which is technically and economically capable for incinerating medical wastes and treatment of combustion gases. Such unit consists of (i) an incineration unit (INC-1) having an operating temperature of 1100 °C at 300% excess air, (ii) combustion-gases cooler (HE-1) generating 35 m 3/h hot water at 75 °C, (iii) dust filter (DF-1) capable of reducing particulates to 10–20 mg/Nm 3, (iv) gas scrubbers (GS-1,2) for removing acidic gases, (v) a multi-tube fixed bed catalytic converter (CC-1) to maintain the level of dioxins and furans below 0.1 ng/Nm 3, and (vi) an induced-draft suction fan system (SF-1) that can handle 6500 Nm 3/h at 250 °C. The residence time of combustion gases in the ignition, mixing and combustion chambers was found to be 2 s, 0.25 s and 0.75 s, respectively. This will ensure both thorough homogenization of combustion gases and complete destruction of harmful constituents of the refuse. The adequate engineering design of individual process equipment results in competitive fixed and operating investments. The incineration unit has proved its high operating efficiency through the measurements of different pollutant-levels vented to the open atmosphere, which was found to be in conformity with the maximum allowable limits as specified in the law number 4/1994 issued by the Egyptian Environmental Affairs Agency (EEAA) and the European standards.

Effect of moisture content on some physical properties of green wheat

Determination of physical characteristics of grain and agricultural commodities is important in the design of harvesting, handling, and processing equipment. Physical properties of green wheat (frikeh) kernels were established over moisture content range from 9.3 to 41.5% (w.b.) which covers the moisture range from harvesting to storage. Increasing of moisture content was found to increase axial dimensions, mass of 1000 seeds kernel surface area, kernel volume, and static friction coefficient, while decreasing bulk density, true density, and porosity. Kernel length, width, thickness, and effective mean diameter increased from 6.24 to 6.66 mm, 3.65 to 4.22 mm, 3.43 to 3.85 mm, and 4.19 to 4.75 mm, respectively. Mass of 1000 seeds was found to increase from 32.57 to 51.95 g. Kernel surface area, volume, and sphericity were found to increase from 47.07 to 61.02 mm 2, 28.84 to 41.95 mm 3, and 0.685 to 0.721, respectively. Bulk density, true density, and porosity were found to decrease with moisture content increase from 711.3 to 675.4 kg/m 3, 1333.2 to 1241 kg/m 3, and 46.65 to 45.59, respectively. Static friction coefficients were found to increase as moisture content increases. Static friction coefficient was largest between green wheat kernels and plywood surface ranging from 0.41 to 0.62, while the largest increase in static friction coefficient with moisture content was observed for stainless steel and ranged from 0.22 to 0.64.

An option generation and selection methodology for process equipment selection

The option generation and selection (OGS) methodology forms part of a general approach for the design of agile chemical plants based on business, product and process knowledge, with support from information models. This paper describes an equipment OGS tool that encompasses the principles of combinatorial process and plant design. The main components of the methodology are: an equipment option generation model described as a set of objects, and the net relationships between them, and an equipment option selection model which consists of procedures for equipment selection. The two models are supported by databases containing information specific to each equipment type, the concept on which the equipment is based, and relationships with other equipment types. Robust, systematic and complete forms of these models can be used as the basis of an expert system for process equipment design, with equipment selected using these tools satisfying the requirements of both specific processes and families of processes (that contain common features, similar functional groups or similar raw material requirements for process operations). Application of the methodology also allows the evaluation of options for reconfiguring existing plant.