Technologies

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Ebara Engineering Review No.182

Internal Flow in a Vaned Return Channel of a Multi-Stage Low Specific Speed Pump

by Motohiko NOHMI, Akira GOTO & Tatsuyoshi KATSUMATA

Flow fields in a vaned diffuser return channel of a multi-stage, low specific speed pump were analyzed experimentally and numerically by using CFD (Computational Fluid Dynamics). A CFD code based on FEM utilizing tetrahedral grids and solution adaptive grid refinement was applied for the flow at the best efficiency point. Tetrahedral unstructured grids were generated automatically in relatively short time even for the case of flow passages with complicated geometry. The calculated result using coarse grids with solution adaptive grids showed a qualitatively good agreement with the result obtained using fine grids, although it took less CPU time in the former case. It was found experimentally that static pressure rises intensively around the throat of the diffuser, and the peripheral velocity component exists at the channel outlet. These flow characteristics were relatively well predicted by CFD. It was also found by CFD that the separated region appears at the diffuser passage and it is extended to the suction side of the deswirl vane passage.

Keywords
Turbomachinery, CFD, Diffuser, Return channel, Tetrahedral unstructured grid, Solution adative grid, Finite Element Method, Diffuser throat, Flow separation, Automatic grid generation

New Method of Numerical Simulation for Improving Road Tunnel Ventilation

by Mingyang JIA, Masanori GOTO, & Masashi OHBUCHI

A new method, named the boundary shift method, was developed for investigating the breath phenomenon at openings of road tunnels. This method eliminates problems encountered when investigating the same by a conventional computational means, especially involving moving and static boundaries as well as the passing of solid bodies. Tests revealed that the breath phenomenon was due to fluctuation of the traffic-induced vortices. This method helps clarify details of forced ventilation, making available data crucial for improvement of road tunnel ventilation.

Keywords
Traffic, Tunnel,Ventilation, Simulation, Turbulent, Pollutant, Opening, Moving boundary, Environment, Multi-block method

A Sludge Thickening-dehydrating System Featuring Single Polymer Conditioning

by Takao HAGINO, Shoichi GOHDA, & Hideki YOSHIDA

Tests were conducted on a sludge thickening-dehydrating system, featuring single polymer conditioning and a concentrator type pelletizer, installed upstream a dehydrator. A pilot system was tested in a 24-hour operation sludge treatment facility for a period of about one year. Test results indicated a sludge treatment rate of about 200 kgDS/mh, which was over two-fold of that by a system using a conventional type pelletizer. This system significantly enhances dehydrating performance and is fit for treating low-concentrated, high-organic-content sewage sludge.

Keywords
Concentrater type pelletizer, Single polymer conditioning, Sludge thicking-dehydrating system, Thickener, Low-concentration sludge, Filtrate, Separation screen, Solid yield, Polymer feeding rate, Moisture content

Development of a Pressurized Internally Circulating Fluidized-bed Boiler

by Norihisa MIYOSHI, Katsuyuki AOKI, Seiichiro TOYODA, Shugo HOSODA, Nobutaka KASHIMA,Shinji SEKIKAWA, Katsutoshi NARUSE, & Hiroshi HASHIMOTO

A pressurized, internally circulating, fluidized-bed boiler (PICFB) was developed and tested at EBARA's Sodegaura Plant. Combustion by different types of coal was studied under various conditions. This boiler was found to be easily operable and controllable, have minimal impact on the environment, and capable of using various types of coal as fuel. The heat generated by the boiler can be used effectively for power generation and chemicals constituents in the exhaust gas can be applied for material recycling. The following introduces this boiler, as well as its scaled-up model, the A-PICFB.

Keywords
Pressurized fluidized bed combustion, Topping cycle, Combustion, Gasification, Coal, High efficiency power generation, Combined cycle, Desulfurization, Synthesis gas, Advanced-PFBC Pressurized fluidized bed

Stainless Steel Submersible Pump for Fresh Water

by Hiromi SAKACHO, & Masahiko KISHI

EBARA's new stainless steel submersible pump series for fresh water has been released into the market. This pump series is YAG laser welded and equipped with an automatic winding machine. It's main feature is that it is totally made of stainless steel, including it's canned motor whose output is maximized. This pump series is highly durable and no rust-contaiminated water results from its operation.

Keywords
All stainless steel product, Canned type submersible motor, Automatic winding machine, YAG laser, Filled resin, Press formed three-dimensional impeller, Magnetic field analysis, Fine blanking, Spline shaft, Lost wax

Wall Cabinet Type Booster Pump System for Direct Water Supply

by Hirokazu HAMADA

A Wall cabinet type booster pump system has been developed for supplying water directly. This system achieves space conservation, as no reception tank becomes necessary, and is more sanitaly compared to conventional such systems. Energy conservation is also realized by the effective use of pressure in the main water pipe and inverters. Some other features would be that the system needs minimum maintenance space and that noise-suppression techniques (for the closed-type outdoor model) are applied. This system has attained certification by Japan City Waterworks Association and other domestic waterworks establishments. Direct water supply systems are expected to become the mainstay in water supply systems in domestic waterworks facilities in the near future.

Keywords
Direct water supply, Booster pump, Main water pump, Reception tank, Estimated constant end-pressure control, Backflow preventer, Save space, Low noise, Inlet pressure drop, Inlet pressure transmitter

RCW Series Absorption Chiller

by Jun MURATA

EBARA's new absorption chiller series, the RCW series, has been released into the market. Its main feature is that steam is used as the heat source. Some other features include compactness, energy-efficiency, inverter-controlled solution circulation, use of a microcomputer control panel, and use of an optional housing for outdoor use. Compared to its predecessor, the 16 JSE series, the RCW series is 8% smaller in width, 19% in height, and 17% in length (for the 360 refrigerating-ton model). It's maintenance is significantly simplified as well. Use of a microcomputer control panel has enabled great functional advantages such as monitoring by display, trouble shooting, and data transmission.

Keywords
Absorption Chiller, Compact design, Energy saving, Inverter, Microcomputer control panel, Housing for outdoor use

Biopack Control Unit

by Jun FUSHIMI, & Shigeki IWAYAMA

Aerobic filtration bed processes, featuring small installation space and easy maintenance, are starting to be adopted in small-scale sewage treatment plants ·EBARA's Biopack Control Unit has been exclusively developed for optimal settings, operational control, and monitoring of such processes. The Biopack Control Unit features the GUI (Graphic User Interface) by which an operator can easily and fully grasp operational conditions. This control unit is currently being used at actual aerobic filtration facilities since July 1996 and excellent feedback is being obtained. The following outlines this control unit and introduces some operational data.

Keywords
Biopack, Aerobic filtration bed process, Control unit, Graphic user interface, Sewage treatment plant, Touchpanel

Slurry Transportation System for Shield Tunnel Method

by Kazuhisa WATANABE, & Kiyonori SATOH

The following introduces EBARA's slurry transportation system for use in tunnel construction by the shield tunnel method. The main components of this system include slurry feed pumps, slurry return pumps,various automatic valves, a central monitoring/control device for monitoring and controlling the operation. The slurry pumps are highly abrasion and clogging resistant and the central monitoring/control device is capable of automatic control of modes based on pre-operation simulations.

Keywords
Slurry shield method, Fluid transportation equipment, Slurry feed pump,Slurry return pump, Limit setting velocity, Face pressure,Slurry transportation

Ventilation System for Ukishima Ventilation Station, Aqualine Trans-Tokyo Bay Highway

by Toshitsugu SASE, & Eisaku MURATA

EBARA's ventilation system is being used for the 10-km undersea vehicle tunnel along the Aqualine Trans-Tokyo Bay Highway. This system is installed at Ukishima Ventilation Station located on an artificial island about halfway along the tunnel. EBARA's system includes longitudinal ventilation equipment equipped with electrostatic precipitators, as well as pressure control equipment set in the sub-floor section of the tunnel for prevention of contaminated air from seeping into this section. The main components of this system are 2 vertical-type, adjustable blade exhaust fans (ø4000 mm), 2 vertical-type, adjustable blade air supply fans (ø1800 mm-driven by pole-change motors), and silencers.

Keywords
Trans-Tokyo Bay Highway, Variable pich axial fan, Tunnel ventilation, Silencers, Ukishima Ventilation Station, Blade adjustment system, Longitudinal ventilation

A Floating-type Solar Energy Storage and Water Purification System for Use in Urban Ponds

by Hiroshi TANIUCHI

A unique clean-energy system has been co-developed by EBARA and NTT (Nippon Telephone & Telegraph) Corporation. This system, designed to be floated in urban ponds, primarily functions as a solar energy storage/supply system for use in emergency situations. It's solar system comprises 60 photovoltaic cells (each 83.5 W) with a rated output of 5 kW. An AC/DC converter and a VVVF enables optimal operation, even when there is a drop in power due to insufficient sunshine. The system's other function is water purification featuring no use of chemicals and the use an aeration system for maintaining the DO in the water, an SS filtration system, as well as a phosphorus removal system. Two units are currently tested in two ponds in Tokyo. Further research is being carried out to upgrade the performance of its functions.

Keywords
Photovoltaic power generation, Floating object, Water purification, Multimedia, Aeration, Filtration, Nippon Telegraph & Telephone CORPORATION, Phosphorus absorption, Bag filter, Tokyo Municipality

Municipal Waste Fluidized-bed Incineration System with High-performance Gas Treatment system - In Use at Tohbu Clean Center, Gifu City -

by Kiyoshi SAITOH, Takeshi YAMAMOTO, Shinya AZUMA, Yoshinori SATOH, Hikaru SETOGAWA, & Hisashi OKADA

EBARA's municipal waste, fluidized-bed incineration plant has been in use at Tohbu Clean Center, Gifu City since March 1998. This system satisfies various pollution standards, especially that for dioxins. This is achieved by the use of both a low-temperature activation catalyst and activated carbon for effective dioxin degradation. Dioxin emission from the system was found to be below 0.1 ng-TEQ/Nm3. Heat from the flue gas is used to generate steam, which in turn drives a turbine to generate electricity of up to 7000 kW. This power is used within the facility and the excess amount sold to an electrical power company.

Keywords
Fluidized-bed incineration, Steam turbine generator, Dioxins, Waste heat boiler, NOx reduction system, Catalyst tower, Activated carbon, Truck control system, Automatic control system, Selling excess electricity to power company

Fluidized-bed Incineration System & Materials Recovery Facility - In Use at Kosai City Environmental Center -

by Shigekatsu ASAO, Kenichi NISHIYAMA, Yasuhide ISHIKAWA, Jyunzo TAKADA, Masaharu OONISHI, Shigenori TAKAHASHI, Gakuji KUMISAWA, Takeshige SHIBA, Akira TSUTIYA, Norihumi INABA, & Masaaki IIO

EBARA's fluidized-bed incineration system and materials recovery facility are being used at Kosai City Environmental Center, a municipal waste incineration plant, since July 1998. The incineration system includes two incinerators, each with an incineration capacity of 60 tons per day. It is also the first such plant in Japan to include a counterflow absorber tower in which activated coke is used to absorb dioxins. The most advanced technology is used in all aspects of this system. The materials recovery facility is capable of recovering 30 tons of materials (metals, plastics, and glass) per day and includes various equipment for recycling and incombustibles treatment, as well as a stock yard for storing recovered materials. Both the incineration system and the materials recovery facility are designed to cause minimal impaction the environment.

Keywords
Fluidized-bed incineration, Recycling facilities, DXNs, Counterflow adsorber, Recycling, Stock yard, CO, Segregation & collection of waste, Crushing & separation, Pollution prevention

Fluidized-bed Incineration System for Municipal Waste - In Use at Kurashiki Seibu Municipal Incineration Plant -

by Hiroyuki SUZUKI, Masato KANEKO, Minoru KANAZAWA, Hajime SASAKI, Hideki MISAKI, & Takahiro KOBAYASHI

EBARA's fluidized-bed incineration system, in operation at Kurashiki Seibu Municipal Incineration Plant since March 1998, features computerized combustion control and use of a high-performance flue gas treatment system. It's two incineratior units are each capable of incinerating 60 tons of municipal waste a day (16-hour/day operation). The flue-gas treatment effectively degrades dioxins and other pollutants and rainwater is recovered for use in the system. It is designed to have the least impact on the environment and is extremely energy-efficient.

Keywords
Fluidized-bed incinerator, Harmful gas removal, Combusion, Control, Gas cooler, Municipal solid waste, Ash treatment, Wastewater treatment

Batch-type Municipal Waste Fluidized-bed Incineration System

by Masayuki KAI, Takeshige SHIBA, & Naoki HACHIYA

EBARA's municipal waste, fluidized-bed incineration system, in operation at Tomigo Clean Center, is equipped with 2 batch-type incinerators, each capable of incinerating 26 tons of waste within an 8-hour operation per day. This system, installed in March 1998, constitutes the nucleus of EBARA's fluidized-bed inciniration technology and has attained excellent feedback, Is is a system which is easy to operate and whose impact on the environment is minimized to extremes.

Keywords
Fluidized-bed, Incinerator, Batch type, Ash cementing equipment, Bag filter, Carbon monoxide concentration

Stoker Firing System for Municipal Waste Incineration Plant

by Kei MIYOSHI, Kazushige KUROSAWA, Kenkai GI, & Masaaki IIO

EBARA's Stoker Firing System has been installed in a municipal incineration plant. This system, which features a batch type furnace (30t/8h), is the first one of its kind in Japan that uses fuzzy controllers and is monitored/controlled by an ACC (Automatic Combustion Control) system. It's startup and shutdown is also done automatically. The flue gas under goes a relatively simple treatment process-water injection cooling system-> air preheater for combustion-> dry-type hazardous gas treatment system-> bag inlet) filter gas temp.: 200ºC). Despite this, the concentration of dioxins in the treated gas is 0.067-0.15 ng-TEQ/m3N, sufficiently below the allowable concentration of 5 ng-TEQ/m3N. This proves the principle that complete combustion of waste in the incinerator is most effective for preventing dioxin emissions.

Keywords
Stoker, Dioxin, Mechanical grate batch combustion type, ACC (Automatic combustion control), Automatic startup and shutdown system, Complete combustion, operation control system, Combustion termination point, Fuzzy controller, Stabilization

Multiple Waste Co-combusting Fluidized-bed Incineration System

by Teruyasu OKAMOTO, Tsutomu HIGO, & Shunji OHSHIMA

EBARA's multiple waste, co-combusting fluidized-bed incineration system is capable of stable combustion at uniform temperature, enabled by thorough mixing of the fluidized bed by a TIF circulation-flow type fluidized-bed incinerator, regardless of fluctuations in the calorific values of the waste. The incinerator and gas cooling chamber are located side by side, thus realizing an integrated setup by which balanced incineration of multiple waste is done in one incinerator. Stable incineration is enabled for a mixture of various waste, including highly calorific resin, sludge and waste liquids. Auxiliary fuel is therefore unnecessary. A bag house is used for dust collection. This plant is in operation since November 1995 and excellent feedback is reported.

Keywords
Fluidized-bed, Incinerator, Co-combustion, Multiple waste, Calorific value, Fluctuation, Solid waste, Sludge, Waste liquid

Engineering Seminar on Fluid Acoustics Lecture 2: Discrete Tone Induced by Vortex Shedding

by Yoshiyuki MARUTA

This is the second of a series of lectures for an engineering seminar on fluid acoustics which focuses on control and utilization of sound generated from unsteady flows. This second lecture presents the generation mechanisms and the control techniques of discrete tones induced by vortex shedding from solid bodies. The Aiolos tone from the cylinder cross flow can be controlled using data on the vorticity and the correlation scale. The roughness on the cylinder surface, the cylinder inclneration, and cross angle between two cylinders, affect correlation scales and sound generation. The distance between two parallel cylinders is the important element for tone induced by flow interference. Tone induced by the cross flow around tube banks have some peak frequency and are amplified by the acoustics resonance. Such tones could be turned down by splitter plates.

Keywords
Aiolos tone, Karman vortex, Circular cylinder, Crossing cylinder, Strauhal number, Flow interference, Tube bank, Acoustic resonance, Vortex shedding, Correlation scale