Technologies

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Ebara Engineering Review No.241

Steam Generation by a Three-stage Temperature Boosting Absorption Heat Pump

by Yukihiro FUKUSUMI, Hiroyuki YAMADA, Tomoyoshi IRIE, & Naoyuki INOUE

Heat sources, such as hot water of 100°C or less and waste gas of 250°C or less emitted from plant processes, are often wasted because their temperature is too low to be utilized. We have developed a three-stage temperature boosting absorption heat pump and built a test apparatus based on it that boosts the waste heat temperature to generate 150°C steam. An operation test of the apparatus has been conducted to verify its effectiveness. Maintaining the shell pressure below the atmospheric pressure during operation ensures exemption from regulations for pressure vessels and significantly reduces the burden of periodic inspection. By generating steam from waste heat, the heat pump is expected to reduce the load on existing boilers and to decrease fossil fuel consumption in the boilers.

Keywords
Waste heat, Waste hot water, Steam generation, Absorption heat pump, Multi-stage, Temperature boosting, Co-generation system

Development of Novel Optical System based on Projection Electron Microscopy (PEM)
for EUV Mask Inspection

by Masahiro HATAKEYAMA, Takeshi MURAKAMI, Kenji WATANABE, Tsutomu KARIMATA, & Kenji TERAO

An optical system based on projection electron microscopy (PEM) has been designed and fabricated to provide an EUV mask inspection system for half-pitch (hp) 16 nm devices. Compared to conventional DUV and SEM optics, the novel optical system based on PEM for EUV mask inspection can perform defect inspection at higher resolution and higher speed. To obtain a defect sensitivity of 16 nm, performance improvement requirements have been estimated with reference to a system for hp 2X nm devices (Ebara’s current system). After that, the novel optical system based on PEM has been designed and fabricated by establishing specifications that meet the requirements. Regarding aberration and transmittance requirements, this paper presents performance improvements achieved in the novel system.

Keywords
EUV mask, Defect inspection, Projection electron microscopy (PEM), Electron optical system, Imaging electron optics, Electron exposure optics, 1Xnm EUV mask, Aberration, Transmittance, Pixel size

Restoring Drainage Pump Stations Damaged by Huge Tsunami Attacks
(e.g the Restoration Construction of the Soma Drainage Pump Station)

by Kumpei KANDA & Kazuhiro ITO

The devastating Great East Japan Earthquake caused damage to many pump stations delivered by Ebara. Restoration activities began soon after the earthquake, and the emergency restoration of some pump stations was done very quickly; at these pump stations, drainage operation could be restarted before the onset of the rainy season in that year. The emergency restoration was followed by full-scale restoration construction, which incorporated several features to meet the requirements for renewing or retrofitting facilities for permanent use. Since the earthquake caused ground subsidence in the coastal area, the pump capacity was reviewed to compensate for the decrease in the drainage flow rate due to an increase in the required pump head. For portions not covered by the preliminary investigation, detailed inspection was performed to propose upgrades. The functions of the facilities were restored to the level before the earthquake through these processes.

Keywords
Earthquake, Tsunami, Restoration construction, Restoration activity, Drainage pump station, Pump station, Emergency restoration, Inspection, Ground subsidence, Upgrade

Two-stage Dam Pumping Station for the South-North Water Transfer Project
in Shandon Province, China

by Naoki YAMAZAKI, Shinya HIBINO, & Honglan ZHANG

The on-site test operation of two-stage dam pumps with a total capacity of 150 m3/s has been completed in Phase 1 of the eastern route of the South-North Water Transfer Project in China. The pumps with a large diameter of 3000 mm feature a unique large size submersible motor connected directly to the impeller via a shaft. Since their inner casing also serves as the motor outer casing, the impeller is mounted overhung on the motor shaft. With the 52-pole synchronous motor and frequency control, the pumps offer a wide operating range to cope with water level fluctuations. The development of large size tubular pumps connected directly to motors will allow the production of pumps that deliver cost-efficient and reliable pumping in the future.

Keywords
Large size submersible, Impeller, 52-pole, Synchronous motor, Frequency control, Tubular

Improvement Work at Atsugi Environment Center

by Kyoji HASHIMOTO, Takumi SHIBATA, Hiroshi SAITOH, & Tsutomu HAYANO

Improvement work has been implemented at Atsugi Environmental Center with government subsidies for “Establishing the Recycling-Based Society” instituted by Ministry of the Environment. The work has aimed both to reduce CO2 emissions and to reduce increasing maintenance costs by renewing aging facilities after 24 years of elapsed operation period since completion of construction.
Under the improvement work, many energy-saving devices has been installed to reduce the plant’s power consumption, also an electrical instrument and control system for excess steam utilization has been upgraded to increase power generation. By these works, CO2 emissions coming from the plant operation has been significantly reduced and stable plant operation has been ensured. Additionally, the optimization of the incineration operation plan in the view of CO2 reduction has became possible by installing a function to monitor and record CO2 emissions.

Keywords
Energy saving, Improvement work, Carbon dioxide, Reduction, Plant life extension, Atsugi, Turbine bypass, Steam condenser, Electric power, Power generation

Full-scale Application of Anaerobic Treatment System
- Co-digestion Plant for Sewage Sludge and Food Processing Waste -

by Kazumasa KAMACHI, Junichi AKIU, & Water and Sewer Department, City of Kurobe

A biomass plant in Kurobe City is operated by Kurobe E Service, a special purpose company (SPC), under a private finance initiative (Build-Transfer-Operate method). The plant provides methane fermentation of a pre-treated mixture of sewage sludge and food processing waste (coffee waste) to ensure good co-digestion with reduced VFA accumulation in the digested sludge. After dehydration of the digested sludge, steam from a biogas boiler is used to dry the sludge; thus, sludge drying is possible using little fossil fuel. A biomass resource recycling system has also been built through the utilization of the dried sludge.

Keywords
Anaerobic digestion, Methane fermentation, Co-digestion, Private finance initiative, Build-Transfer-Operate method, Sewage sludge, Food processing waste, Coffee waste, Full-scale plan