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Ebara Engineering Review No.224

Development of High-efficiency Centrifugal Refrigerating Machine

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.

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

Verification of Sludge Reduction by Ozonation System with Phosphorus Recovery process

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.

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

Development of CMP Topring - ai head GⅢ

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.

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

Methane Fermentation Process for Treating Distillation Residue

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.

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

Lecture on Corrosion and Corrosion Protection of Seawater Pumps - Part 5: Corrosion and Corrosion Protection of Stainless Steels and Ni-Resist Cast Irons -

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.

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