Ebara Engineering Review

by Masao MATSUMURA, & Shinta KUNITOMO
Reducing energy consumption is a crucial factor for the prevention of global warming. Studies are underway in Japan, as well as in many other countries, on measures for achieving such reduction. Energy saving is beneficial for modern civilization and serves as an effective deterrent against a return to primitiveness.
EU's progressive attempts in reducing the energy consumption of pumps are yielding favorable results. The energy consumption of pumps in Japan is a factor that can not be neglected. Measures must be worked out and implemented accordingly. The following discusses that optimal pump design, including the machining on the outer diameter of impellers and controlling the pump rotational speed, is an effective means for achieving energy saving.

Keywords
Pump, Energy saving, Rotational speed control, Energy labeling scheme, Climate change, Eup directive, Ecodesign, Inverter, Efficiency, Head

by Kazuhiro NAGAOKA
Energy saving at potable water supply facilities has been attempted by improving pump operation control. Improving the overall water distribution system, not just mechanical efficiencies, is a crucial factor in achieving energy saving when carrying out large-scale renovation to upgrade aging water supply systems. The following exemplifies one such case.

Keywords
Energy saving technology, Operation control, Water supply system, Distribution pump

by Masahito KAWAI
A study was made on the energy consumption of various booster units for high-rise buildings and housing complexes. Results indicated that using direct connecting booster pump systems, estimated constant end-pressure control, and PMSMs (Permanent Magnet Synchronous Motors) enabled about 70% reduction in power consumption, compared to the case of using current conventional means. However, booster systems are operated under significantly smaller than rated flow rates most of the time. Thus, it is possible to conserve power by employing a train of multiple small-rated pumps and controlling their OFF/ON in an optimal way. The relationship among the specifications of the structure housing the booster system, instant maximum water consumption, and water consumption patterns needs to be clarified to determine the type and number of pumps which would enable optimization.

Keywords
Direct connecting booster pump system, Estimated constant end-pressure control, Permanent magnet synchronous motor (PMSM), Instant maximum water consumption, Water consumption pattern

by Shigeo TAKITA, Kazutoshi ARAI, Fuminori ETO, & Kenichi UMEMURA
The torque characteristics during an axial flow pump startup, focusing on the operating point transition of a not fully water-filled startup, were studied. Comparison was made among numerical results of model case analysis, actual in-site data, and analytical data. TRAP Ⅲ, a fluid transient analysis program developed by Ebara,was used for the simulation. The effectiveness of this program was confirmed and the use of this method of evaluating the torque characteristics of axial flow pumps is looked forward to.

Keywords
Axial flow pump, Startup torque, one-dimensional unsteady flow analysis, Not fully water-filled startup pipe, Siphon, Inertial effect coefficient, Complete characteristics, Static friction torque, Adding mass of water, Locus of operating point

by Mitsutoshi YAMAMOTO, Tetsuji IGUCHI, Minoru SASAKI, Takehiro OKA, Motoshi ARIHARA, & Masamitsu KOSHIMA
The performance of a leading-edge stoker type incinerator system, currently in operation at a municipal waste incineration plant, has been assessed. This system follows a DBO (Design-Build-Operate) plan in an effort to realize cost-effectiveness and superior servicing. A next-generation stoker, featuring exhaust gas recirculation and a forced, air-cooled grate, constitutes the core of this system. The exhaust gas recirculation enables low excess air ratio operation, reduced exhaust gas emission, and improved heat recovery. Moreover, the NOx reduction effect by this system enables selective non-catalytic reduction, thus making catalytic denitrification unnecessary. Assessment results confirmed stable operation of this system.

Keywords
Next generation stoker technology, Exhaust gas recirculation, Forced air cooled type grate, Low excess air ratio, NOx reduction, Design build operate method, Dioxins, Selective non-catalytic reduction, Arakawa Clean Center, Incineration plant

by Nobuhiro HIGAKI, Masahito KAWAI, & Hirofumi NAKANIWA
An EMC (ElecroMagnetic Compatible) system has been newly employed to test large-output pumps and water supply systems operated under actual load conditions. The shielded room of this system features a design which fully considers the use of water. It includes a pump operation facility whose features and capabilities are unprecedented in other such test systems. and whose interior has enough space to allow testing of large-scale machinery. Moreover, the system's power source facility and EMC test apparatus make it possible for conducting EMC tests on high-current capacity equipment and pump products for export.

Keywords
EMC, EMC test, Shielded room, Immunity, Emission, Ground plane, Main terminal interface voltage, Electrostatic discharge immunity test, Electrical fast transient/burst immunity test, Surge immunity test

by Hiroyuki KAWASAKI, & Hiroaki OGAMINO
A novel atmospheric pressure type turbomolecular pump has been developed for the microchip/IC manufacturing industry, as well as for SEM applications. This pump makes it unnecessary to use backup by auxiliary pumps, needed for creating an ultra-high vacuum environment by conventional turbomolecular pump operation. This new pump is fully oil-free, compact and featuring exceptionally high compression performance. Development was centered on the minimization of vane clearance by introducing thin ceramic multi-stage centrifugal vanes, as well as optimal dynamic and sensor-less magnetic bearings.

Keywords
Atmospheric pressure type TMP, Ceramics centrifugal vane, Dynamic bearing, Backup pump, Sensor less magnetic bearing, Thrust force, Ultra high vacuum, Destructive torque

by Tadashi YAMAGUCHI, Naoyuki INOUE, Tadashi SATO, Atsushi KANEKO, Shuichiro HONDA, & Hiroyoshi WATANABE
A high-efficiency, centrifugal refrigerating machine has been developed and is expected to be released into the market within this year. This novel and unprecedented centrifugal refrigerating machine features a duplex refrigerant cycle for enabling a high COP of 7.0 (under a rated condition), a high-efficiency compressor driven by a gear-less, high-speed motor which is inverter controlled. Performance test results indicated favorable temperature, partial load, and control characteristics.

Keywords
Centrifugal refrigerating machine, Duplex cycle, Inverter, High speed motor, Air-conditioning system, Heat exchanger, Compressor without gear, COP, Impeller, Partial load

by Kiyomi ARAKAWA, Terunobu SUYAMA, & Toshihiro TANAKA
The process of sludge reduction by ozonation liquefies sludge and consequently generates organic matter and nitrogen, which flow into the biological treatment process and increase the treatment load. Therefore, the addition of ozonation to an existing biological treatment system may result in insufficient oxygen supply for biological treatment. From the fact that the large part of the ejected gas from ozone reactor is oxygen, the authors aimed and made the best use of this ejected gas as resource of oxygen supply to develop a biological treatment process (Anaerobic-Anoxic-Oxic) by excess sludge reduction.
We also expected recovery of phosphorus as hydroxyapatite phosphate on the basis of supernatant liquid on the anaerobic tank. We set this plant and made evaluations of the process capability at the location of EXPO 2005 Aichi, Japan.

Keywords
Sludge reduction, Anaerobic-anoxic-oxic process, Ozonation, Phosphorus recovery, Hydroxyapatite phosphate, Ejected gas from ozone reactor, Oxygen consumption

by Hozumi YASUDA
A novel CMP topring, ai head GⅢ series, has been developed. This series features not only improved polishing performance, but also a saving in consumables, improved maintainability, productivity, and monitoring sensitivity. Furthermore, this topring series enables significant minimization in retainer ring abrasion.

Keywords
Chemical Mechanical Polishing, Topring, Polishing head, Wafer, Within wafer non-uniformity, Monitoring technology, Productivity increase, Retainer ring, Membrane, Dresser

by Masaaki NISHIMOTO
An energy-saving methane fermentation process has been developed for treating distillation residue at an "Awamori" distillery (Max. 15 t/day of distillation residue). In this process, excess steam from the distillation is recovered and put to use, thus achieving cost-effective residue treatment. This stable process also meets the fluctuating demand in the residue as a fertilizer and fodder.

Keywords
Methane fermentation, Anaerobic digestion, Bio-gas, Distillation residue, Awamori, Energy, Steam, Fertilizer, Landfill, Fodder

by Matsuho MIYASAKA
The corrosion resistance of stainless steels is maintained by the passive film on its surface. However, this passive film becomes destroyed when chloride ion is present, and can result in localized corrosion such as crevice corrosion, pitting corrosion and stress corrosion cracking (SCC). The following discusses the characteristics of stainless steel, exemplifies actual corrosion cases and introduces protective technologies. Some characteristics of Ni-Resist cast irons are that its corrosion rate is evenly slower than that of conventional cast irons and that it is not subject to crevice corrosion and pitting corrosion. The disadvantage is that it is susceptive to SCC. Mechanisms and behavior of Ni-Resist SCC and measures against the same are discussed.
The use of seawater pumps made of duplex stainless steels in coastal regions with high corrosivity, or at desalination plants, is increasing in recent years. Also introduced are results of corrosion tests on duplex stainless steels carried out in the Middle East, as well as actual application examples of duplex stainless steel seawater pumps.

Keywords
Seawater pump, Stainless steel, Ni-Resist cast iron, Crevice corrosion, Pitting corrosion, Stress corrosion cracking (SCC), Intergranular corrosion, Duplex stainless steel, Middle East, Desalination plant

by Kenichi SUGIYAMA, Takashi ENOMOTO, & Shuji HATTORI
A technique has been developed for predicting wear volume loss for impellers of pumps susceptible to slurry wear by sand particles in river water. Predictions can be used to determine applicable wear resistant materials and maintenance factors for pump impellers. The wear depth distribution of impeller blades of an aluminum pump was studied, the results of which were found to correspond well with slurry wear test results of the same. Industrial application of this technique is highly recommendable.

Keywords
Slurry wear, Wear depth distribution, Prediction, Pump impeller, Maintenance, Slurry jet test

by Masahiro SERIKAWA, Kenichi SASAKI, & Yuji SENDA
CVD-made conductive diamond electrode exhibit outstanding stability compared to the noble metal electrodes in wastewater treatment as well as high COD removal efficiency. Stable diamond electrode with size enough for industrial use has been developed. Results of a field test carried out using a pilot plant equipped with a diamond electrode stack indicated stable operation. Current trends in diamond electrode technology for wastewater treatment is discussed in this paper.

Keywords
Diamond electrode, Wastewater treatment, Electrode stability

by Tomoko TATSUZAWA, Ling-yun HAO, Shohei AYAME, Naoaki KATAOKA, & Akiko MIYA
The behavior of acidogenic and methanogenic microbial consortia in cellulose-containing wastes was studied to collect physiological and ecological data for enhancing the degradation and methane gas yield of anaerobic digestion processes. In particular, the effect of HRT (Hydraulic Retention Time) on the profile of four acidogenic and three methanogenic anaerobic microorganisms in a thermophilic anaerobic digester, for treating toilet paper and organic wastes, was investigated by a quantitative PCR method. The methanogenic activity and population of microbial consortia was found to be stable under a run under an HRT of 35 days and an OLR (Organic Loading Rate) of 2.3 g-CODCr/(L·d), The JC3 strain was found to be the predominant cellulose degrader while the reactor was undergoing stable operation. In the case of a run under an HRT of 23 days, the loss of methanogenic activity could not be recovered by stopping the feeding. However, VFA (Volatile Fatty Acids) accumulation, especially acetate and propionate, continued and the population of genus Methanoculleus could not be recovered.

Keywords
naerobic digestion, Cellulose-degrading bacteria, Methanogenesis, Thermophilic, Polymerase chain reaction (PCR), Quantitative PCR

by Yasunari KURIHARA, & Takehiro KOYAMA
Ice thermal storage systems equipped with high-efficiency heat-pumps have been installed in air-conditioning facilities of Tokyo Subcenter Metro Subway line stations. The main features of these systems are: 1) Use of compact, high-efficiency heat-pumps, 2) Use of compact, high IPF (Ice Packing Factor) container type ice storage tanks, and 3) Use of an optimal air-conditioning control system which can match particular subway power consumption and air conditioning load factors. Compared to using conventional such air conditioning systems, the implementation of these ice thermal storage systems are expected to achieve a 40% reduction in annual running cost and a 24% reduction (670 tons) in CO₂emission.

Keywords
Heat-pump, Ice making mode, Cooling ice melting mode, Chilling mode, Ice thermal storage system, Ice packing factor, Ice storage tank, Power consumption, Load prediction, Peak adjustment

by Sadayoshi TAKAHASHI, Fuminori ETO, Hideaki FUEKI, Wutichai PITUKLERDKUL, & Piya JARASMATUSORN
This wind tunnel system, initially developed for domestic use, had been equipped at an overseas Japanese company facility under a "full turnkey" contract. After reviewing simulation test results according to precision requirements (airflow distribution at the main outlet in particular), decision was made to manufacture and construct the system locally. Favorable airflow performance test results, upon completion of the system, indicated that the wind speed distribution at the 3.0 m section of the main nozzle outlet was below 3%, while the same at the 1 m section of the secondary nozzle outlet was below 1%. These test results confirmed that the precision in airflow distribution was fully adequate. It is expected that this system, an outcome of Ebara's wind tunnel expertise and airflow simulation technology accumulated over many years, will be further developed and see more use in the international market.

Keywords
Wind tunnel, Environmental, Main fan, Settling chamber, Contraction nozzle, Airflow simulation, Airflow performance, Airflow distribution precision, Sun-light system, Overseas operation

by Matsuho MIYASAKA
The authors have developed a 2D, 3D and axisymmetric boundary-element-method (BEM) system. This system makes it possible to quantitatively estimate cathodic protection and macro-cell corrosion, such as galvanic corrosion and differential-aeration-cell-corrosion. Understanding the physical quantities (potential and current densities) on the surface of corroding materials is of primary importance in solving corrosion problems, The developed BEM system does not require internal elements discretization which constitutes difficulties when analyzing complicated 3D regions. Internal element discretization is used in conventional analysis techniques, e.g. finite-difference-method (FDM) and finite-element-method (FEM). In this paper, some history on the development of corrosion analysis is introduced, followed by an outline on the BEM and BEM system. Also included are verification experiment results and examples of application for cathodic protection and galvanic corrosion, to demonstrate the analytical accuracy and effectiveness of the BEM system.

Keywords
Boundary element method (BEM), Corrosion analysis, Cathodic protection, Galvanic corrosion, Seawater, Pump, Potential, Current density, Polarization curve

by Hiroyuki YAMADA, Hiroshi YOKOTA, Manabu NOGUCHI, Shunsuke SHIMIZU, & Tohru KATO
A novel energy-saving process for producing high-purity hydrogen has been developed. Pretreated biogas, such as by desulfurization, is fed into the anode side of solid oxide electrolysis cells, while steam is fed into the cathode side of the same. High-purity hydrogen becomes produced by electrolysis at a temperature exceeding 700℃. Performance test results indicated the effectiveness of this process which was confirmed to be capable of producing hydrogen by low-voltage electrolysis. The configuration of this process is simple and various biogas from various biomass sources could be used for producing hydrogen. This process can be also applied at facilities which produce various low-grade reductive gases.

Keywords
Hydrogen production, Biomass, Biogas, Solid oxide electrolysis cell, Steam reforming, Steam electrolysis, Digestion gas, Gasification of biomass, SOHG

by Hiroyuki KANDA, Junko MINE, Satoru YAMAMOTO, Keiichi KURASHINA, Keisuke HAYABUSA, Akira SUSAKI, & Tsutomu NAKADA
A next-generation interconnect technique for Cu damascene electroplating machines has been developed. This leading-edge technique, which features Cu plating on thin Ru seeds, reduces the terminal effect and enhances uniformity by the placement of a highly resistive element between anodes and cathodes. This technique allows favorable film thickness distribution and film quality, and filling performance.

Keywords
Terminal effect, Cu electroplating, High resistive substrate, Porous resistive element, Ru seed, Uniformity, Filling performance, Surface roughness, Resistivity

by Tomoharu TEJIMA, Takahide KOMATSU, Sachiko MIYAUCHI, Kazuhiro KANEDA, & Nobuhiro HIGAKI
A control system backup unit for a high-head, computerized, packaged water supply booster system (Model F3100 for high-rise buildings) has been developed. This backup unit makes it possible to supply water, much in the same way as during normal operation, when there are occurrences of irregularities, including CPU board and pressure sensor malfunctions. The unit's 2 CPU board design has enabled it to be compact, thus minimizing installation space. The automatic switchover to the backup system enables minimal water stoppage when the main control system malfunctions. An optimal, continuous water supply has been made possible by an estimated constant end pressure control function.

Keywords
Control system backup unit, High-head, Packaged booster system, Pressure control, Backup operation, Controller, Pressure sensor, Backup circuit, Communication, Water stoppage

by Katsuyuki SASAKI, Kazuo HAGIWARA, & Kensuke ONDA
A novel UV treatment system has been developed for use in water purification processes as a measure against chlorine-resisting pathogens, in particular Cryptosporidium. The following outlines the R&D of this system and provides data on actual application at a water purification plant.

Keywords
Cryptosporidium, Inactivation, Water purification, Ultraviolet radiation, UV dose, Low-pressure UV lamp, Medium-pressure UV lamp, Bromate

by Masunobu ONOZAWA
A bevel polishing system, the EAC 300bi-hp, has been released into the market to answer demands in the semiconductor for higher throughput, footprint shrinkage, and lower cost of consumables (CoC). This unprecedented flexible system upgrades the former model, the EAC 300bi-T, which is attaining a boost in the yield of mass produced semiconductor devices. In particular, this system enables a 3.3 time increase in throughput, a 16% reduction in footprints, and about a 70% reduction in CoC, compared to the same by conventional such systems.

Keywords
Wafer edge, Wafer bevel, Bevel polishing, Immersion lithography, Wafer thinning, Knife-edge, Edge bead, Etching, Edge exclusion, High-K

by Matsuho MIYASAKA
Special attention is required for galvanic corrosion in seawater as, depending on conditions, its speed of progress can become multiple-fold than that of other corrosion (of single material) in seawater. When materials constituting parts with different corrosion potentials are used together in seawater, macro-cells form between these parts, with seawater as the electrolyte, and galvanic corrosion promotes the corrosion of materials whose potential is on the base side. In contrast, corrosion of materials with their potential on the noble side becomes inhibited. Cathodic protection (galvanic anode and impressed current) is a method which makes effective use of this corrosion inhibition phenomenon. The following discusses an actual case of galvanic corrosion in a seawater pump, features and protective measures, as well as the features and application of cathodic protection.

Keywords
Corrosion, Seawater, Pump, Galvanic corrosion, Cathodic protection, Galvanic protection, impressed current protection, Sacrificial anode, Potential, Polarization curve