Industrial Engineering Commons^™

Load Flow Solution For Three-Phase Mv Radial Distribution Connected Network Supplying Different Line Topologies, B. J. Kundy

Tanzania Journal of Engineering and Technology (TJET)

In this paper, a load flow solution for the Medium Voltage (MV) three-phase radial distribution in delta-delta (Δ–Δ) connected network supplying different line topologies such as three phase, phase to phase and single-wire earth return (SWER) networks is presented. The general voltage related network equations are developed using Kirchhoff’s voltage and current laws. Development of a solution to the load flow analysis applying the developed general voltage related network equations is proposed in order to evaluate the network voltage profile. Various numbers of arrays are developed for the identification of the network under study. The proposed method is a new …

An Integrated Model For Technology Assessment And Choice For Rural Development In Developing Countries, Abdallah Chungu

Tanzania Journal of Engineering and Technology (TJET)

Abstract

A System Thinking Approaching Maintenance, Production And Quality, E. A. M. Mjema

Tanzania Journal of Engineering and Technology (TJET)

The concepts of system thinking and its applicability in maintenance management was analysed in this article. The author analysed various maintenance policies, which have inclination to the concept of system thinking. The maintenance policies revisited include the Integration of Maintenance (IM), Total Quality Maintenance (TQMain), Failure Mode and Effect Analysis (FMEA), and Total Productive Maintenance (TPM). All these strategies are aimed at utilising effectively the maintenance personnel by giving some of the responsibilities of maintenance to production personnel. It was found that, although the founder of these techniques did not mention the concepts of system thinking in their methods, however, …

Why Toyota And Honda Topped The 2002 J.D. Power Quality Study, Susan Lightle, Kenneth Yale Rosenzweig, John Talbott

Accounting Faculty Publications

Toyota again topped the annual J. D. Power and Associates quality study released in late May of 2002. Toyota scored the highest mark ever with l 07 defects per l 00 vehicles, while Honda came in second with 113 defects. The study was based on responses of approximately 65,000 new car owners queried during their first 90-days of ownership.

These results do not surprise us, as we have been fortunate to make numerous sojourns to the Toyota plant in Georgetown, Kentucky, and observe the manufacturing processes. These trips were normally facilitated by a former Japanese student of ours, Minako Yanke, …

Evaluation Of The Distribution Of Taguchi's Signal-To-Noise Ratio And The Effectiveness Of The Signal-To-Noise Ratio For Detecting Changes In The Mean And/Or Variance, Jinsuk Lee

Masters Theses

The concept of parameter design developed by Taguchi to achieve robust engineering is widely promoted in industry as a means to design a product whose output is largely immune to noise in the system. Taguchi has used the signal-to-noise (S/N) ratio to summarize measures over the noise factor settings at the parameter design and to allow control of the experiment.

The objectives of this investigation are: 1) to infer distributions of S/N ratios (lower-the-better S/N, higher-the-better S/N, and nominal-the-best SIN), and 2) to determine the effectiveness of the S/N ratio as a means for identifying changes in the mean and …

Value Stream Improvements Using Kanban For The X-Workcell, Jason Noble

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Jason Noble on August 26, 2003.

Development Of A Multicriteria Spatial Decision Support System With Application To The Economic Optimization Of Aircraft Based Weather Data Collection, Ganzague Erol Osman Ozan

Engineering Management & Systems Engineering Theses & Dissertations

This research is motivated by the economic optimization of the Troposherical Airborne Meteorological Data Reporting (TAMDAR), an aircraft-based meteorological data collection system. In the envisioned TAMDAR system, meteorological data collected by the onboard sensors of selected aircraft are transmitted to the ground as aircraft fly their missions. The data is processed by a national center, which disseminates the data to diverse users such as weather forecasters and aviation control centers. Substantial government funding is required for the implementation and operation of this new data acquisition system and data transmission expenditures constitute the largest portion of the costs. To achieve economic …

Information System Product Development By Integration Of Kano's Customer Satisfaction Model With Quality Function Deployment, Afife Yesim Sireli

Engineering Management & Systems Engineering Theses & Dissertations

Product development of complex, innovative information technology related systems presents difficult challenges for technology managers, and new product failures are a significant problem. The main reason for this is insufficient decision-making due to the lack of a customer-oriented product development process in the information system (IS) companies, which is often related to deficiencies in cooperation between R&D and marketing departments. Integrating consumer requirements into the product design phase is an important factor for improving market success. Therefore, a product development decision model is needed for the managers of information system companies to make more accurate decisions about the characteristics of …

A Statistical Evaluation Of Risk Priority Numbers In Failure Modes And Effects Analysis Applied To The Prediction Of Complex Systems, Anthony W. Dean

Engineering Management & Systems Engineering Theses & Dissertations

Complex systems such as military aircraft and naval ships are difficult to cost effectively maintain. Frequently, large-scale maintenance of complex systems (i.e., a naval vessel) is based on the reduction of the system to its base subcomponents and the use of manufacturer-suggested, time-directed, preventative maintenance, which is augmented during the systems lifecycle with predictive maintenance which assesses the system's ability to perform its mission objectives. While preventative maintenance under certain conditions can increase reliability, preventative maintenance systems are often costly, increase down time, and allow for maintenance-induced failures, which may decrease the reliability of the system (Ebeling, 1997). This maintenance …

Optimization-Based Architecture For Managing Complex Integrated Product Development Projects, Hisham Mohamed El-Sayed Abdelsalam

Mechanical & Aerospace Engineering Theses & Dissertations

By the mid-1990's, the importance of early introduction of new products to both market share and profitability became fully understood. Thus, reducing product time-to-market became an essential requirement for continuous competition. Integrated Product Development (IPD) is a holistic approach that helps to overcome problems that arise in a complex product development project. IPD emphasis is to provide a framework for an effective planning and managing of engineering projects. Coupled with the fact that about 70% of the life cycle cost of a product is committed at early design phases, the motivation for developing and implementing more effective methodologies for managing …

Preface, The Editors

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

No abstract provided.

Investigation Of Initial Fouling Rates Of Calcium Sulfate Solutions Under Non-Boiling Conditions (Work-In-Progress), Feridoun Fahiminia, A. Paul Watkinson , Norman Epstein

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

This study initiates an experimental investigation of how process variables such as temperature and velocity affect the initial precipitation fouling rate of the inverse solubility salt, calcium sulfate, under sensible heating conditions. The effect of fluid velocity and temperature on the delay time is also being measured.

Large-Scale Plasma Polymer Coating On Heat Exchanger Fins For Improving The Wettability, Ki-Hwan Kim, Dae-Hwan Yeu, Samchul Ha, Seok-Keun Koh

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

This research presents the results of the recently developed large-scale hydrophilic polymer coating by plasma polymerization, optimum plasma zone (OPZ) process. The excellent hydrophilicity of heat exchanger fin surface could give good effects to efficient drainage of condensate water as well as heat transfer performance. The hydrophilicity of layer treated by large-scale OPZ system is excellent irrespective of line speed from 0.6 m/min to 2.4 m/min. The good lateral uniformity of the hydrophilicity could be acquired in large scale OPZ treatment. The application of OPZ technique to the heat exchanger could enhance the efficiency of heat transfer, resulting from decrease …

Heat Exchanger Fouling In Phosphoric Acid Evaporators - Evaluation Of Field Data -, R. M. Behbahani, H. Müller-Steinhagen, M. Jamialahmadi

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Multistage evaporators are frequently used in phosphoric acid plants to increase the concentration of dilute phosphoric acid to 52-55 wt% P₂O₅. The concentrated phosphoric acid solution is supersaturated with respect to calcium sulfate. As a result, part of the calcium sulfate in the liquor deposits on the heat exchanger tube walls. Since the thermal conductivity of these scales is very low, thin deposits can create a significant resistance to heat transfer. Therefore, regular cleaning of heat exchangers is required, frequently at less than biweekly intervals. As the major costs in modern phosphoric acid plants are the …

Fouling During The Use Of Seawater As Coolant - The Development Of A ‘User Guide’, S. Pugh, G.F. Hewitt, H. Müller-Steinhagen

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

ESDU International of London, UK has recently published a ‘User Guide’ on fouling in heat exchange systems using seawater as the coolant. Developed over a period of eighteen months in close collaboration with a team of oil refiners, heat transfer equipment and services suppliers and universities, with valuable input from the power industry, the User Guide is a practical guide to the current state of knowledge relating to fouling in cooling systems using seawater. Its objective is to provide the designer and the operator of both onshore and offshore equipment with a practical source of guidance on the occurrence, the …

Study Of The Influence Of Bulk Properties And Surface Tension On The Deposition Process Of Calcium Phosphate On Modified Stainless Steel, R. Rosmaninho, G. Rizzo, H. Müller-Steinhagen, L. F. Melo

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

In order to reduce the fouling caused by milk during heat treatment, it is important to know more about the deposition process of calcium phosphate, one of the main components of milk fouling, on stainless steel surfaces. The fouling behaviour of calcium phosphate is controlled by several factors related to both the fouling solution properties and the surface characteristics. The present work is focused on the influence of two of these factors: 1) the size and size distribution of the calcium phosphate aggregates formed in solution upon heating and 2) the surface tension values of the deposition surface. It was …

Crystallisation Fouling Of Mixed Salts During Convective Heat Transfer And Sub-Cooled Flow Boiling Conditions, A. Helalizadeh, H. Müller-Steinhagen, M. Jamialahmadi

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The mechanisms of mixed salt crystallisation fouling on heat transfer surfaces have been investigated for convective and sub-cooled flow boiling heat transfer. Effects of various operating parameters such as solution composition and hydrodynamics of the system, on crystallisation fouling of mixtures of calcium sulphate and calcium carbonate have been studied experimentally. The results of the experiments were used to develop a mechanistic model for prediction of fouling resistances. Model predictions were compared with the measured experimental data when calcium sulphate and calcium carbonate form and deposit on the heat transfer surface, simultaneously. Deviations ranging from 6% to 25% were observed …

Sodium Aluminosilicate Solid Phase Specific Fouling Behaviour , Jonas Addai-Mensah, Jun Li, Marek Zbik, Scott Rosencrance

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Process heat transfer equipment fouling due to sodium aluminosilicate precipitation is a serious problem that confronts high-level nuclear waste liquor and Bayer process alumina processing plants. The fouling of 316 stainless steel substrate by thermodynamically stable and unstable sodium aluminosilicate polytypes: amorphous solid, zeolite A, sodalite and cancrinite crystals, been has studied in an isothermal, batch precipitation system at 65 °C. Fouling invariably occurred via heterogeneous nucleation, crystal growth and particulate adsorption processes, accompanied by solution-mediated, phase transformation and morphological changes. For the thermodynamically stable cancrinite fouling, the amount of scale deposited increased systematically with increasing crystallization time before levelling …

Permanent Hydrophilic Surface Formation By Ion Assisted Reaction, Ki-Hwan Kim, Jun Sik Cho, Sung Han, Young Whoan Beag, Byung Ha Kang, Samchul Ha, Seok-Keun Koh

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Since totally wettable hydrophilic polymer surfaces from hydrophobic polymers (PMMA, PTFE, PET and PC) have been demonstrated for the first time at Materials Research Society meeting, 1995 Fall meeting, Boston, the application of ion assisted reaction (IAR), in which energetic ions (0.5~1.5 keV) are irradiated on materials with blowing reactive gases near the irradiating surfaces, has been extended to various polymer, ceramic and metal for creating permanent hydrophilic surfaces. The surface energy was measured by Youngs equation and the highest energy, E_s, of 60~70 mN/m, which is similar to surface energy of water (E_s of H_{2 …}

Crystallization Fouling Of The Aqueous Two-Component System Caso4/Caco3, Volker Höfling, Wolfgang Augustin , Matthias Bohnet

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Solutions, which cause fouling problems, consist mostly of more than one single component. Up to now only few studies concerning the fouling phenomena in such multicomponent systems exist. Therefore batch and continuous experiments with the aqueous two-component system CaSO₄/CaCO₃ were carried out, investigating especially the influence of pH-value on the fouling behaviour. As measure for the crystalline deposit the fouling resistance R_f was used.

The composition of the obtained fouling layers were analysed by x-ray diffraction and scanning electron microscopy (SEM). Further the strength of the crystalline deposits were determined in abrasion experiments. The measured abrasion …

A Comparison Of The Operating Characteristics Of Two Cooling Water Systems Using Chlorine And Chlorine Dioxide Biocides, T. R. Bott, I.E. C. Mott

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Tests using side streams from an industrial cooling water system have been made to compare the corrosion rates associated with the use of chlorine and chlorine dioxide biocides. Two streams were employed, a "once through" and a recirculating system employing a cooling tower. The water used in the plant originated from a canal. The results of the tests revealed differences in characteristics between the circuits, depending on the biocide used and the operating conditions. The data obtained demonstrated a higher corrosion rate of 1.5 mpy with chlorine compared to 1.0 mpy using chlorine dioxide.

Deposition Of Na2Co3 In Supercritical Water Oxidation Systems And Its Mitigation, M. S. Khan, S. N. Rogak

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Supercritical water oxidation is a technique to destroy wet organic waste. The oxidation reaction takes place at high temperature and pressure. Organics are miscible at these conditions but inorganic salts are not soluble and present fouling problems. Examples of these salts are sodium sulfate and sodium carbonate.

Research is being done in the University of British Columbia to study the fouling behavior of Na₂CO₃ in the SCWO reactor. The working fluid is heated by passing alternating current through the reactor wall. Since the tube surface was hotter than the bulk fluid, the salt was expected to nucleate …

Physical Water Treatment For The Mitigation Of Mineral Fouling In Cooling-Tower Water Applications, Young I. Cho, Sunghyuk Lee, Wontae Kim, Sangho Suh

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The physical water treatment (PWT) device is defined as a non-chemical method of water treatment utilized for the purpose of scale prevention or mitigation. Three different PWT devices, including permanent magnets, solenoid coil device, and high-voltage electrode, were used under various operating conditions. The present study proposed a bulk precipitation as the mechanism of the PWT and conducted a number of experimental tests to evaluate the performance of the PWT. The results of fouling resistances obtained in a heat transfer test section clearly demonstrated the benefit of the PWT when the PWT device was configured at an optimum condition. The …

Direct Measurement Of The Forces Required To Disrupt And Remove Fouling Deposits, W. Liu, Z. Zhang, G. K. Christian, P. J. Fryer

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

In cleaning, the force required to disrupt the deposit and remove it from the surface tends to be inferred from flow data, rather than being known directly. A novel micromanipulation technique has been developed to measure directly the adhesive strength of food fouling deposits on a stainless steel surface. A T-shaped stainless steel probe pulls fouling deposits away from the surface to which they are attached. The apparent adhesive strength between the fouling deposits and the substrate can be measured as the work required to remove the deposits per unit area from the substrate. Tomato pastes and whey proteins have …

Analysis And Steps To Mitigate Heat Exchanger Fouling In An Aromatics Plant, Shinji Isogai , Mitsutaka Nakamura

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

A heat exchanger, upstream a distillation tower for the separation of BTX (benzene, toluene, xylene) from crude benzene in an aromatics plant, experiences heavy fouling. The fouling mechanism and countermeasures to mitigate or eliminate it, were investigated. An Alcor Hot Liquid Process Simulator (HLPS)was used for the fouling rate measurement. The main mechanism is a combination of precipitation fouling and chemical reaction fouling. Effects, such as temperature, vapor ratio (vapor mole fraction of the fluid), heater materials, surface roughness and the addition of some different types of chemicals were studied. From the experiments, some countermeasures for this fouling were proposed. …

The Balance Between In The Cleaning Of Milk Fouling Deposits, G. K. Christian , P. J. Fryer

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Deposits formed on the surface of heat treatment equipment in the dairy industry compromise product quality and process efficiency. Frequent cleaning is needed to ensure consumer safety and optimal process operation. Cleaning solutions generally have a high environmental impact; the need is to minimize their use. We have studied the physics and chemistry of cleaning at two length scales of measurement: (i) the effect of cleaning chemical and water on deposits within a plate heat exchanger (PHE), and (ii) the effect of process variables on small fouled disks. The chemical nature of cleaning of dairy deposits is shown clearly by …

Retrofitting Crude Oil Refinery Heat Exchanger Networks To Minimise Fouling While Maximising Heat Recovery, B. L. Yeap, D. I. Wilson, G. T. Polley, S. J. Pugh

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

The use of fouling factors in heat exchanger design and the lack of appreciation of fouling in traditional pinch approach has often resulted badly designed crude preheat networks that are expensive to maintain. The development of thermal and pressure drop models for crude oil fouling has allowed its effects to be quantified, so that techno-economic analyses can be performed and various design options compared. Application of these fouling models is carried out on two levels: on the assessment of adding extra area to individual exchangers, and the design of a complete network using the Modified Temperature Field Plot. Application to …

Heat Treatment Improvement Of Dairy Products Via Ohmic Heating Processes : Thermal And Hyrodynamic Effect On Fouling, M. A. Ayadi, L. Bouvier, F. Chopard, M. Berthou, J. C. Leuliet

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Fouling and consequently cleaning of heat exchangers in the dairy industry are nowadays a significant issue still not solved for the processing of quite a large variety of products. Ohmic heating processes for food products a priori are well known to minimize the fouling phenomenon due to a totally different way of heating food by admitting the current directly in the product. Such a technology could be a good alternative to counter both fouling and cleaning aspects when pasteurizing or sterilizing dairy desserts known to generate large amounts of soil on heated surfaces. The aim of this experimental study was …

Removal Of Particles From A Powdery Fouled Surface Due To Impaction, M. S. Abd-Elhady, C. C.M. Rindt, J. G. Wijers, A. A. Van Steenhoven

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

Particulate fouling is defined as the unwanted deposition of particles on heat exchange surfaces. The fouling layer reduces the heat transfer rate and leads to inefficient operation. The net fouling rate is the result of the difference between the deposition rate and the removal rate of particles. One of the mechanisms that contribute to the removal of particles from powdery fouled surfaces is the collision of an incident particle with the fouled surface. In the present study, removal of particles from powdery fouled surfaces due to an incident particle impact is studied numerically and experimentally. A numerical model is developed …

Chemical Cleaning Of Oil Refinery Heat Exchangers -- The Need For A Joint Effort, Himanshu M. Joshi, Glen Brons

Heat Exchanger Fouling and Cleaning: Fundamentals and Applications

One component of the high cost of fouling to oil refineries is the maintenance money spent to clean fouled heat exchangers and the associated lost production while the exchanger is out of service. This presentation will highlight some specific fouling situations in oil refineries which can benefit from chemical cleaning. Cooperative efforts are needed between refinery operators, researchers, and chemical suppliers to develop the proper solvents and to find the optimum procedures to use them for cleaning.