Ebara Engineering Review

by Arihiro OKAMOTO
The Hiratsuka-city Kankyoujigyou Center (Environment management center) is a facility that was built based on a “design, build, and operate” (DBO) scheme. This facility, whose period of operation is 20 years, has been operating steadily for the approximately 1.5 years since its completion and delivery in September 2013. It is equipped with fluidized-bed incinerators with a treatment capacity of 315 tons/day (105 tons/24 hours × 3 units). Taking advantage of the features of the fluidized-bed incinerators, the facility keeps the fluctuations in transmitted power small while treating waste stably, thereby maximizing its functions as a green power plant.
This paper reports the operation conditions of the facility over the 1.5 years since its completion and the measures which are adopped to the generated/transmitted power control.

Keywords
Fluidized-bed, Waste, Incinerator, Waste to Energy (WtE), Gross/Net thermal efficiency, Control of generated power, Control of transmitted power

by Daisuke KOGA, & Takao HAGINO
Japan’s demand for phosphorus is met entirely by imports. It is an extremely valuable resource that is indispensable to fertilizers and industrial applications. On the other hand, sewage treatment plants face issues such as reducing the phosphorus load in discharged water and the level of scaling caused by phosphorus. To address these issues, the mechanical agitation-type magnesium ammonium phosphate (MAP) method was developed. This method makes it possible to recover the phosphorus in digestive sludge in the form of MAP. The joint agri-service research consortium of Swing Corporation, the Kobe City Government, and Mitsubishi Corporation was commissioned by the Ministry of Land, Infrastructure, Transport and Tourism to conduct a demonstration of the technology at a real-scale demonstration plant as part of a “Breakthrough by Dynamic Approach in Sewage High Technology Project (B-DASH Project).” The demonstration confirmed that the method reliably delivers the desired level of performance, and it is estimated to recover around 1.8 times the MAP of conventional methods. Because MAP has already been registered as a fertilizer, Swing is conducting a joint study with Kobe City Government on practical applications in the Kobe area.

Keywords
Phosphorus, MAP (struvite), Crystallization, Anaerobic digested sludge, Fertilizer

by Naoto AKIBA, & Tetsuji IGUCHI
We delivered the Iwamizawa Environment Clean Plaza, a waste incineration facility with a stoker-type furnace, to Iwamizawa City, Hokkaido at the end of March 2015. This facility is designed to treat the waste collected from three municipalities: Iwamizawa City, Bibai City, and Tsukigata-cho. The Iwamizawa Environment Clean Plaza is a comprehensive waste treatment facility that consists of a stoker-type incineration plant and a recycling plant. This cutting edge facility creates a low environmental impact thanks to state-of-the-art stoker technology. It also provides for the advanced treatment of flue gas, and works to effectively utilize energy by generating electricity from waste heat at incineration. The facility gives full consideration to the harmony with both of the natural and social environments, while seeking to provide the economic benefits to the municipalities it serves. We employed various measures, including introduction of pre-fabricated stokers, to cope with the very short delivery time from the contract to the completion of construction. The performance test confirmed that the facility achieved the designed performances.

Keywords
Stoker type incinerator, Incineration plant, Recycling plant, State-of-the-art stoker technology, Low air ratio combustion, Flue gas recirculation, Generating power from waste, Prefabricated stoker, Pin-bound type grate, Closed wastewater treatment system

by Yoshio KUDO, Hideyasu TAKEDA, Hiroyuki OSAWA, & Makoto KOMIYA
The Shinkawa-kako drainage pump station, which is one of the nation’s largest drainage pump stations, built in Nishikanbara district, Niigata city, has just undergone renewal construction of the pump facilities. In the construction, the tubular type horizontal axial flow pumps of bore 4200 mm with a concrete casing structure were removed and replaced, with the existing building frame reused. This was challenging work because all the six pumps had to be replaced in turns, one pump in the dry season each year, while the draining function of the pump station was being maintained. Although a variety of issues arose at the time, the renewal construction was steadily carried out to be completed based on know-how obtained from similar work conducted by EBARA.
The first report described the features of this drainage pump station and the design considerations of the renewal construction. Therefore this second report introduces viewpoints and innovative ideas of renewal construction on the site.

Keywords
Concrete casing, Renewal construction, Wire sawing, Tubular type horizontal axial flow pump, Adjustable vanes, Reuse, Underground structure, Drainage pump station, Dry season

by Nobuhiro HIGAKI
We discussed various water supply systems, their purposes and how to select them, in the first and second series of technical introduction of the water supply equipment (water supply unit) which comprises our company’s main products. Subsequently, we explained the “ON-OFF control system”, the most basic pressure control system among water supply systems, and the “variable frequency control system” which is superior to the “ON-OFF control system” in suppressing water pressure fluctuations and which can operate with a high degree of energy saving, in the third and fourth parts of the series respectively.
In this fifth part of the series, we will introduce the “direct connecting booster pump system”, which is a system that increases only necessary water supply pressure in a way that makes up for insufficient pressure of the main pipe while taking advantage of its pressure with water supply equipment directly connected to a pipe branched from the main pipe, and also explain about the water supply equipment that utilizes the system. We will include details of the control system, its actual structure and main components, various special specifications, and protective functions for its safe operation.

Keywords
Water supply equipment, Water supply system, Direct connecting booster pump system, Variable frequency control system, Back flow preventer, Estimated constant end pressure control, Flow switch, Pressure sensor, Direct connecting booster pump system (serially cascaded type)

by Yongsheng GE, Ryosuke HATA, Hiroshi SAKUMA, Shinji GONO, Hisami NAKAMURA, & Akira YAMAGUCHI
This study examined a nitrogen removal process based on an anammox (anaerobic ammonium oxidation) process that enables lower energy consumption and processing at lower costs than the conventional method. On the basis of the findings of a basic study of the partial nitritation process and the anammox process using synthetic wastewater, demonstration tests using actual wastewater were conducted. First, a demonstration test was conducted with fluid with digested sludge filtrate that had been separated from sewage and that was characterized by a low concentration of organic substances and a high nitrogen concentration. It was followed by another demonstration test using leachate with a low amount of suspended solids (SS) and organic substance concentrations and a high level of salinity. Both tests lasted about six months or longer. These tests confirmed that both the partial nitritation process with added carriers and the anammox process enabled bacterial attachment and retention of carriers and exhibited stable processing performance. Yet another demonstration test using this fluidized carrier method integrating the partial nitritation process with the anammox process observed a T-N load of 2.4 kg/(m3·d) at maximum with digested sludge filtrate and 2.7 kg/(m3·d) at maximum with the leachate. It also confirmed good nitrogen removal performance with a T-N removal rate of 80% or higher on average in both cases.

Keywords
Nitrogen removal, Nitritation treatment, Anaerobic ammonium oxidation (Anammox), Ammonium, Fluidized carrier method, Free ammonium, Free nitrous acid, Digested sludge, Dewatered filtrate, Leachate

by Hiroyuki SUZUKI, Nobuyuki OTABE, Tetsuji MARUYAMA, & Yoko SATO
Ebara Environmental Plant Co., Ltd. recently finished the construction of an industrial waste incineration system for Clean Power Yamagata Co., Ltd. and delivered a fluidized-bed waste incineration system. Incorporating the twin interchanging fluidized-bed (TIF)incinerator, this system takes advantage of the mixing and crushing effect of fluidized-bed to treat mixture of various waste including sludge, waste oil, liquid waste, waste plastics etc., with compliance to severe emission standard and with high-efficiency power generation.

Keywords
Industrial waste, Sludge, Fluidized-bed, Incinerator, Combined waste incineration, Monitoring and operational control equipment, Distributed control system (DCS)

by Teruaki TSUKAMOTO
Waste incineration facilities are recently required to be more stanch to serve as disaster prevention facilities in addition to providing value-added functions, such as effective energy utilization and contribution to local communities. The Musashino Clean Center has attracted attention as an urban facility adjacent to a municipal government building. Its design-build-operate (DBO) project, including 20 years of operation, was tendered for under the comprehensive evaluation system in 2013. Ebara Environmental plant Co., Ltd. submitted a proposal reinforcing the concept sought by the municipal government by making the most of the latest technologies and 29 years of operational experience. This paper reviews the facility’s enhancements in quake resistance, construction of a cogeneration system that coveres neighboring facilities in preparation for emergency and support to temporary evacuees, facility design ensuring early resumption of independent operations and the creation of safe and secured facilities on the basis of the experiences of the Great East Japan Earthquake.

Keywords
Waste incineration, Disaster-prevention facility, Toughening, Energy, Seismic design, Cogeneration system, High efficiency power generation from waste

by Motohiko NOHMI
This paper explains erosion problems caused by pump cavitation. A single spherical bubble with low pressure shrinks rapidly if it flows into a high pressure area; when the bubble finally collapses, it generates a high pressure wave propagating to ambient solids. If the bubble is close to the ambient solid surface and deforms into a non-spherical shape, a micro jet directed toward the solid surface is generated and impinges against the surface. In a situation where a number of bubbles collapse repeatedly, multiple loads are applied onto the solid surface, resulting in erosion. In order to evaluate the erosion resistance characteristics of materials, two standards, ASTM G32 and ASTM G134, have been established as cavitation erosion tests on materials. Pump erosion can be reduced by using excellent erosion-resistant materials or by applying partial build up welding. Development of erosion prediction by numerical analysis is expected in the future.

Keywords
Cavitation, Cavitation erosion, Bubble collapse, Micro jet, ASTM G32, ASTM G134, Built up welding

by Kazuhiro KANEDA
We provided explanation on the topics of various water supply systems, their purposes and how to select them, in the first and second series of technical introduction of the water supply equipment (water supply units) which are our company’s main products. In the third series, we explained the “ON-OFF control system”, the most basic system of controlling pressure among water supply systems. In this fourth part of the series we will cover the “variable frequency control system”, which is superior to the “ON-OFF control system” in suppressing water pressure fluctuations and can operate with a high degree of energy saving, and the water supply equipment that utilizes the system. The introduction will include topics such as details of the control system, actual structure and main components, various special specifications, and protective functions for its safe operation.

Keywords
Water supply equipment, Water supply system, Variable frequency control system, Inverter, Energy saving, Estimated constant end-pressure control, Control system backup, Pressure sensor, Special specifications, Protective function

by Takeshi IZUMI, Makoto KOMATSU, Tatsuya DEGUCHI, Daisuke AKUTAGAWA, Takeshi MANABE, & Yusuke NAKANO
From the viewpoint of the minimizing the corrosion of the spent fuel rods and structural material in the spent fuel pool, the ion exchange resins are generally used as one of purification system in order to keep water quality clean.
Hydrogen peroxide generated by the radiolysis of water exists in the pool water and it accelerates the oxidation decomposition of the ion exchange resins and finally, it becomes the cause to shorten the resin life.
To solve this problem, the application of Pd doped resins which can decompose hydrogen peroxide catalytically at the surface has been considered. It was confirmed by the cold test that Pd doped resins overlaid on the ion exchange resins decomposed hydrogen peroxide contained in the pool water and inhibited the oxidative degradation of the ion exchange resins.
Based on the results, hot examination tests by using actual pool water in Tsuruga-2 were carried out from Jan. 2014 to Mar. 2014. We report the results of these tests.

Keywords
Pd doped resins, Hydrogen peroxide, Ion exchange resins, Spent fuel pool, Nuclear power plants

by Teruaki TSUKAMOTO
Energy reuse such as the ability to generate power has become increasingly important among the roles of municipal solid waste incineration facilities, besides their original purpose of sanitization. Additionally, their expected role has recently begun to include one as a base of operation in the event of a disaster. This has resulted in a further demand for incineration facilities to run stably and continuously on a long-term basis. Ebara Environmental Plant Co., Ltd. improved existing fire grates and stoker structure, and developed a pin bound type fire grate with higher mechanical stability and maintainability. The company further introduced this technology into a municipal solid waste incineration facility to conduct a continuous long-term stable operation test, verifying its effect. It thus successfully developed a new stoker furnace suitable to treat waste of various characteristics.

Keywords
Municipal solid waste, Incinerator, Stoker, Fire grate, Pin bound type

by Kazumi OHKANDA, Takahide OZAWA, & Yasutaka KONISHI
A new variable speed type pump, model HPE, was launched in November 2014 as an integrated pump of model HPF (variable speed type) and model HPA (fixed speed type), which have been commercially available since 2004 and 2007 respectively, as a water supply pump for household use. This HPE model meets the recent market needs for energy saving and low noise operation in residential areas, combining a high-efficiency pump, a permanent magnet synchronous motor equivalent to IE4, and a controller and an inverter with efficient operation. In the 250 W model, compared to conventional models (model HPA), approximately 48% of energy saving and as low as 12 dB (A) of noise are achieved.

Keywords
Inverter, Permanent magnet synchronous motor, Constant pressure control, Energy saving, Low noise operation, External output, Lead-free, Shallow wells, Incombustible material, Compatibility

by Ryoji OOTAKE, Yuta NAGANO, & Takafumi KOGUCHI
We delivered the reverse running pump turbine with the 800 x 700 mm pump diameter and auxiliary machinery to Hokkaido Electric Power Co., Inc. Shumarinai Power Station, and performed installation and commissioning on site. The reverse running pump turbine is less expensive than the reversible pump-turbine, and has almost the same efficiency in terms of pumping and generating operations. To introduce the reverse running pump turbine, we conducted a model test with a miniature pump in advance to identify operation characteristics. We also decided on the equipment specifications and control methods based on the results of the hydraulic transient analysis. This facility adopts rotation speed control using inverters and converters in order to operate properly as conditions change on-site. The completion of this power station enables previously unutilized irrigation discharge water to be collected as electric energy.

Keywords
Reverse running pump turbine, Hydroelectric power station, Unutilized energy, Variable-speed operation, Frequency control, Model test, Hydraulic transient analysis

by Kazutaka OKUDA
This series introduces technologies for EBARA water supply equipment that is our main product, and the types, uses and selection of water supply systems were explained in the previous two articles. This third article provides an introduction of the "ON/OFF control system,"which is the most basic pressure control system among water supply systems, and the water supply equipment controlled thereby. Control system details, the actual structure and main components, various special specifications, and protective functions for safe operation are illustrated.

Keywords
Water supply equipment, ON/OFF, Control system, Pump, Pressure tank, Inching, Pressure sensor, Special specifications, Flow switch, Protective function

by Keisuke HAYABUSA, Dai KUDO, Kikuo KISHIMOTO, & Tadaharu ADACHI
A rotating shaft is designed by comparing calculated stress for expected load with material strength. Because unexpected force is often applied to the shaft in an actual machine, the generated stress can be larger than the calculated one. Strain gauge method is generally applied rotating shafts by using a slip ring or telemetry. However measurement accuracy is decreased by electrical noise generated from motors in the machine. In the paper, the method of two-dimensional thermoelastic stress measurement was developed to determine fluctuating distribution of stress in the rotating shaft. Bending stress in the rotating shaft could be accurately identified by using inverse analysis with images taken from multiple positions of a thermographic camera. Validity and efficiency of the method were confirmed on the basis of numerical and the experimental results and the accuracy of the stress was also found to depend on reference temperature in the measurement.

Keywords
Stress analysis, Nondestructive inspection, Shaft, Inverse problem, Thermography, Rotary bending, Temperature change

by Mitsuteru FURUYA, & Tomomichi ISHIYAMA
Spreading and expanding a heat pump system utilizing ground thermal energy, which is one of the renewable energies, require an understanding of the characteristics of the system and the establishment of an optimal control method according to conditions.
East Japan Railway Company and Ebara Refrigeration Equipment & Systems Co., Ltd. jointly conducted a demonstration experiment with the aim of establishing a control method to make the most efficient use of ground thermal energy. Experimental equipment for a ground source heat pump (GSHP) system was installed on the premises of East Japan Railway Company in Saitama City, Saitama Prefecture, and test operations were conducted for 8 months from July 2013 to February 2014 to grasp the operating characteristics of borehole type GSHP. Furthermore, an optimal control method was devised based on the observed data.

Keywords
Renewable energy, Ground source heat pump (GSHP), Optimal control method, Ground heat exchanger (GHE), Ground thermal energy usage, Visualization, Time required for recovering underground temp.,Radiant panel

by Motohiko NOHMI
This paper explains vibration and noise problems caused by pump cavitation. The compression property of cavitation bubbles provides a spring factor in the fluid. The behavior of a single bubble is described by Rayleigh-Plesset equation. As for the whole of the bubbles in the pump, the continuity equation, cavitation compliance, mass flow gain factor and a lumped constant model of piping systems are combined to analyze their behaviors. Vibration of cavitation bubbles in various frequencies causes broadband cavitation noise. The phenomenon in which all the cavitation bubbles in the pump vibrate at a low frequency is a one-dimensional unstable phenomenon called cavitation surge. Three-dimensional unstable phenomena include rotating cavitation and alternate blade cavitation. Many studies have been conducted regarding the cavitation instability in inducers.

Keywords
Cavitation, Cavitation noise, Vibration, Cavitation surge, Rotating cavitation, Alternate blade cavitation, Cavitation instability, Inducer, Cavitation compliance, Mass flow gain factor

by Hirokazu HAMADA
Water supply equipment, which is used to supply water to facilities such as collective housing and office buildings, has some series corresponding to several water supply systems. Each series has its own model lineup covering different kinds of pump bore and motor output. This paper explains how to calculate the water supply capacity and pressure to choose an appropriate model from the various types of water supply equipment, as well as the installation, piping and wiring of the equipment.

Keywords
Water supply equipment, Calculation of water supply capacity, Calculation of water supply pressure, Installation method, Outdoor installation, Suction piping, Discharge piping, Power supply specifications, Electrode control of the reception tank, Electric noise