Ebara Engineering Review

by Hiroshi YAKUWA, Norio TAKAHASHI, Matsuho MIYASAKA, Shuhei NAKAHAMA, Shigeru SAWADA, & Toshio NARITA
A sulfidation-resitant, Ni-based superalloy was developed as a material for rotors of FCC (Fluid Catalytic Cracking) gas expander turbines. The superalloy consists of 3.0 mass% of Al and 1.5 mass% of Ti and a basic composition of AISI 685. Its sulfidation-corrosion resistance is two-fold better than that of AISI 685, while its high-temperature strength and hot workability are equal or higher than that of the same.

Keywords
Gas expander, Superalloy, Corrosion resistant, Sulfidation, Turbine, High-temperature material

by Yumiko NAKAMURA, Kensuke ONDA, Chikako TAKATOH, & Akiko MIYA

Sewage treatment plant effluents are suspected to supply natural estrogenic hormones (17β-estradiol (E2), estrone (E1), and estriol (E3)) to environmental water. As estrogens could be strong endocrine disruptors, it seems to be very important to investigate the behavior of estrogens in sewage treatment plants. To achieve this objective, an analytical method to quantify the estrogens in sewage samples was required. In this study, an analytical procedure based on solid-phase extraction and liquid chromatography/tandem mass spectrometry (LC/MS/MS) has been developed. Good linearity of the calibration curve (r>0.998) was obtained in the concentration range from 0.2 ng/ml to 125 ng/ml for E1, from 0.5 ng/ml to 125 ng/ml for E2 and E3; and the detection limits were 0.2 ng/l for E1, 0.5 ng/l for E2 and E3. The recoveries of standard samples spiked to sewage water were 98.9-102.5%. Using this method, the estrogens in a municipal sewage treatment plant and those in a domestic sewage treatment plant were quantified. The obtained data were compared with the data obtained by ELISA or the estrogen-like activity obtained by yeast assay. The concentrations of E2 by ELISA were generally higher than those by this method. The contribution of E1 was comparably high, especially in the effluenc samples. Estrogens were found to contribute greatly to estrongen-like activity of sewage samples.

Keywords
17β-estradiol, Estrone, Estriol, Liquid chromatography/tandem mass spectrometry, Sewage water

by Hiroshi SAKUMA, Tatsuya DEGUCHI, Kenji SAWAI, Ryo FUJII, & Masaaki NISHIMOTO
A simulation of a media-added anaerobic-anoxic-oxic process was done using an activated sludge model to study the water quality. Experimental data obtained from the continuous treatment of actual sewage by a pilot plant was used. Studies revealed that the changes in the water quality resulting from the simulation and that from the experiment matched, thus suggesting that it was possible to simulate treatment at an actual plant. It is expected that improving the constituent ratio of organics in the raw water, as well as the biofilm model itself would heighten the precision of the simulation, thus making it possible to use simulation for supporting operation management and design planning.

Keywords
Sewage treatment, Activated sludge, Biofilm, Simulation, Nitrification, Denitrification, Phosphorus removal

by Nobuyuki TERAWAKA, & Hirofumi NAKAYAMA
A novel seawater feed pump unit, featuring Type FPS plastic pumps, has been developed for eliminating problems (peeling of nylon coatings, crevice corrosion & pitting) carried by conventional such pump units. The use of metal parts in seawater-exposed sections are minimized and measures taken against damage caused by salt in seawater unexposed sections, thus enabling a long-life, highly reliable unit. Desired amounts of seawater can be pumped at desired times without the use of any overhead tanks. The following introduces and discusses features of this unit's components, control methods and specifications.

Keywords
Seawater feed pump unit, Plastic pump, Polyvinyl chloride piping, Bladder type pressure tank, Ultrasonic type flow detector, Pressure switch, Continuous priming, Specified pressure feeding, Parallel and alternate operation

by Takahide KOMATSU, & Kaoru YAGI
This new wall-cabinet type, booster pump system (Model PNE) for direct water supply system is easier to install at a site than conventional such systems. As parts which tend to be exchanged frequently are positioned at the front surface of the cabinet, easy maintenance is enabled. The use of a sensorless DC motor and a high-sealing cabinet has achieved considerable noise reduction.

Keywords
Direct water supply system, Booster pump, Wall-cabinet, Construction, Maintenance, Sensorless DC motor, High-sealing, Low-noise, High-effciency, Lightweight

by Masahito KAWAI
A solar submersible pump system which uses photovoltaic cells as the power source has been developed. This system comprises a 4-inch, deep-well, submersible pump and a solar controller. A PMSM (Permanent Magnet Synchronous Motor) is used as the submersible motor. Upgrade in system efficiency and compactness were achieved by the application of an exclusively high-speed design. The solar controller features an exclusive MPPT (Maximum Power Point Tracking) control function. High reliability is realized by a dry run protection function, in addition to the normal operation protective function, with full consideration given to the system's use in remote areas.

Keywords
Photovoltaic cell, Maximum power point tracking (MPPT), Permanent magnet synchronous motor (PMSM), Submersible pump, Deep-well submersible pump, Protective function, Dry running protection, Shutoff running protection

by Teruyuki NAKAJIMA, & Manabu YAMAMOTO
A cogeneration package (a type of small distributed power generator set) with a non-pressurized heat recovery device equipped on a micro-gas-turbine, a power generation output of 80 kW and an overall efficiency of 73% has been developed. The main components, such as the gas turbine, recuperator and fuel gas compressor are installed in upper and lower stages, thus conserving installation space and making it easier for maintenance work to be carried from the front and back of the package. The ventilation is made optimal as well. The package features a cubicle-shaped, integrated, indoor-outdoor noise prevention and the noise level is minimized to 65 dB (A). Also featured is an instrumentation system, which conforms to the technical standard thermal power generation, and a power gridtied protected device, which is in accordance to the guideline for grid-tie operations. Combined use using the master control panel enables peak cut operation, scheduled operation and parallel operation of up to five micro-gas-turbine cogeneration packages.

Keywords
Micro-gas-turbine, Cogeneration, Recuperator, Heat recovery device, Fuel gas compressor, Power conditioner, Cubicle construction, Grid-tie, Master control panel, Remote monitoring system

by Hiroshi YAMAGUCHI, & Yuichiro HIRAKO
EBARA's pump system at the Toyanogata Drainage Pump Station (Total drainage capacity: 40 m3/second) in Niigata Prefecture features many innovations in pumping technology. This large-scale pump station has started operation in December 2002 and is functioning as a means of flood control for Toyanogata, a region which is between two rivers. The pump system was developed with cost reduction and upgraded reliability as the main objectives. Its capability of high flow velocity operation, its use of a vertical gas turbine engine, the omission of a overhead traveling crane, and the use of a space-efficient air supply and exhaust system for the gas turbine have achieved considerable compactness. Reliability is upgraded by the use of a floating seal for a totally dry operation, an operation support system and a remote supervisory control system. The following outlines the pump station and its pumping system.

Keywords
Cost reduction, High flow velocity, Gas turbine-engine, Ejector system, Surging, Hydraulic analysis, Remote control, Fiber optic communication, Large scale projector

by Shunji OHSHIMA, Kiko UCHIYAMA, & Hideaki HARADA
A new fluidized-bed, gasification melting furnace (treatment capacity: 198 t/day of general waste and office waste) had been installed and operation has begun from February 2003. This space-efficient furnace is equipped with a 4 000 kW turbine generator for supplying power to adjacent facilities. In particular, the concentration of dioxins in the exhaust gas has been greatly reduced, 0.0013- 0.0076 ng-TEQ/m3 (NTP) (versus the allowable standard of 0.05 ng-TEQ/m3 (NTP)). A dynamic simulation system was delivered prior to the installation of the actual furnace, by which operational training was successfully provided to the clients.

Keywords
Gasification, Melting, Oxygen, Simulator, Dechlorination, Dioxin, Turbine, Generate, Slag, Ube city

by Yuichi IIDA, Atsushi SHIMODA, & Takao KOBAYASHI
A new fluidized-bed gasification and ash melting plant (140 t/24 hours, 3 sets) has been successfully installed at Asahi Clean Center, Kawaguchi City. The main features of this plant are: 1) Mixed combustion and melting of ash (into slag) from the other incineration plant, 2) Fly ash recirculation and milling treatment of incombustibles (resulting in reduction of landfill residue), and 3) Oxygen enrichment for low calorific waste combustion. Boiler steam is mainly used to drive a power generation turbine (Max. 12 000 kW). The generated power is used within the facility and surplus power is sold to the local electric power company. The average treatment at this plant is 142 tons of waste/day/line and 11.4 tons of ash/day/line. Out of 8 300 kW of power generated 3 800 kW are sold to the local electric power company (in case of three lines operatinon).

Keywords
Gasification furnace, Ash melting furnace, Slag, Slag conversion rate, Ash recirculation, Oxygen enrichment, Delivered ash, Wet scrubber, Dioxyns, Power generation efficiency

by Tomoyuki SONE
A stoker firing system was installed at a municipal incineration plant equipped with an ash melting system. This is resulting in the dioxin concentration in the exhaust gas at the stack outlet to be well below 0.1 ng-TEQ/m3(NTP). The slag from the ash melting system was confirmed to be effective and safe to be used as road material. Part of the slag produced during the operation is being actually used as part of road monuments within the plant premises as a test. The heat generated in the incinerator is recovered as steam in the boiler and used within and outside the plant as a heat source, also to generate a maximum of 4 500 kW using a turbine. The generated electricity is used within the plant and excess amounts sold to the local electric company.

Keywords
Stoker, Ash melting, Waste, Incinerator, Slag, Mud gun, Metal, Ash, Boiler, Bag filter

by Kaoru YAMAZAKI
EBARA's stoker firing system has been installed at a totalized waste treatment plant in Hirosaki, Aomori Prefecture. This system features two high-temperature incinerators (123 t/day each) capable of degrading dioxins, a high-temperature, high pressure boiler (3.9 MPa, 400oC, energy recovery type), and a two-stage bag filter with consideration given to ash melting. The ash melting facility features pretreatment for prevention of fly ash contamination and is capable of treating 40 tons of ash per day. The resource production facility is capable of handling and recovering diversified waste (100 t/day).

Keywords
Stoker, Ash melting, Waste, Incinerator, Slag, Metal, Ash, Boiler, Bag filter, Recycle