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Ebara Engineering Review No.194

A Study on the Effects of Alloy Elements on the Sulfidation of Ni-based Alloy for FCC Power Recovery Turbines

by Hiroshi YAKUWA, Norio TAKAHASHI, Matsuho MIYASAKA, Shuhei NAKAHAMA, Cheng FANG, & Toshio NARITA

A study was made on the effects of alloy elements (Ti, Mo and Al) on the sulfidation of Ni-20Cr-13.5Co alloy (a basic composition of AISI 685, used as rotor material of gas expander turbines) in H2-H2S mixtures. The sulfur partial pressure was 10-7-10-4 Pa (at 873 K). The alloy surface became entirely covered with a sulfide scale under a pressure atmosphere of 10-4-10-5.5 Pa. The sulfidation resistance of the alloy improved when Mo or Al was added, more improvement by the latter, under the same atmosphere. Under a sulfur partial pressure of 10-7Pa, however, internal sulfidation occurred. The depth of internal sulfidation was found to be more shallow along the increase in the Al content in the alloy.

Keywords
Power recovery turbine, Ni-base alloy, Sulfidation, Gas expander, Corrosion resistance

High-temperature Erosion-corrosion Behavior of Boiler Tube Materials under Fluidized-bed Waste Incinerator Conditions

by Manabu NOGUCHI, Hiroshi YAKUWA, Matsuho MIYASAKA, Hideyuki SAKAMOTO, Shigeru KOSUGI, & Toshio NARITA

The damage behavior of various materials of a boiler tube under high temperature, erosion-corrosion conditions was investigated. Significant increase in metal loss was found under erosion-corrosion conditions, compared to such loss either in only erosion or corrosion conditions. This increase in the metal loss was attributed to the incapability of corrosion resistance to be maintained consequent to damage incurred on the protective scale due to corrosion. The metal loss speed was influenced on whether there was a scale or not and excessive metal loss occurred along the diminishing of the scale. The metal loss of materials corresponded to the erosion resistance in cases where the influence of corrosion was small. However, depending on corrosion conditions, there was less metal loss in some materials whose corrosion resistance was inferior. This was attributed to the fast growth of scales, whereupon there was less effect by corrosion.

Keywords
Erosion-corrosion, Incinerator, Fluidized-bed, Scale, Molten salt, Erosion-corroion mechanism, Wear, Corrosion

Abatement of Emission from an Existing Fluidized-bed Incineration Plant

by Mitsuyoshi KANEKO, Ikuo NAKAGUCHI, & Shigeru YAMAGUCHI

Abatement of Emission from an Existing Fluidized-bed Incineration Plant by Mitsuyoshi KANEKO, Ikuo NAKAGUCHI, & Shigeru YAMAGUCHI An abatement of dioxin emission is being achieved at an existing fluidized-bed incineration plant. The incinerator facility, the flue gas treatment facility and the fly ash dioxin cracking facility were modified at this plant as a measure against dioxin emission, in accordance to new governmental guidelines. The dioxin concentration in the flue gas is being minimized to below 0.1 ng-TEQ/m3 (NTP), the value stipulated in the guidelines. As for dioxins in the fly ash, which constitute the majority of total dioxin discharge from the plant, over 99% is being degraded by cracking (thermal dechlorination). The estimated amount of total dioxins emission is being reduced to 0.34µg/ton of waste.

Keywords
Fluidized-bed incinerator, Abatement of dioxin emission, Hagenmaier dioxin cracking process, De-NOx catalytic reactor, Amount of dioxin emission, Fly ash, Municipal solid waste

Performance of the EGSB Reactor in High-load Organic Wastewater Treatment

by Yasuhiro HONMA, Toshihiro TANAKA, Susumu ADACHI & Yuichi ISOZAKI

EBARA's EGSB (Expanded Granular Sludge Bed) reactor features the rapid removal of gas, produced in activated sludge treatment processes, by a multi-layered, gas-solid separation device installed in the reactor. Granular sludge in the reactor is maintained, thus enabling a high-load treatment which is two-fold to that by conventional UASB (Upflow Anaerobic Sludge Blanket) reactors. CODcr removal of 83%-91% was achieved in treating soft drink manufacturing and beer brewery wastewater, both of which had a CODcr volumetric load of 30-50 kg/(m3•day). R&D is underway to equip the EGSB reactor with a methane gas recovery device, storing the recovered gas in fuel cells for generating electricity. The use of EBARA's EGSB reactor is expected to become widespread for energy-recovery type, sewage and wastewater treatment systems.

Keywords
EGSB reactor, UASB reactor, Methane fermentation, Granular sludge, Gas solid separator, Organic wastewater, High load treatment

RED Series Absorption Chiller-Heater

by Wataru ITO, Jun MURATA, & Nobutaka MATSUDA

The RED Series Absorption Chiller Heater, featuring the use of gas and oil as a heat source, has been developed, practicalized, and released into the market. This high performance, compact and lightweight machine achieves an energy saving of 39% when compared to the energy consumption of conventional models. Its minimized CO2 emission contributes to less impact on the environment and its operation can be controlled by microcomputer. Prior to its release, various tests were conducted covering over 1000 hours of operation, all with favorable results, thus establishing the reliability of EBARA's RED Series Absorption Chiller-Heater. The following introduces this new chiller-heater and the test results.

Keywords
Absorption chiller-heater, Energy saving, Compact and lightweight design, Microcomputer control panel, Low NOx burner, Test

Pumping Facility for Underground Dam

by Mitsuharu SUZUKI, Yoshikatsu YAMAMOTO, Yasushi KAWAI, & Yasuo SHIBATA

EBARA's pumps have been installed for transmitting well water from an underground dam to a irrigation reservoir in Miyakojima, a remote island in Southern Japan. This underground dam, the nation's largest of its kind (total storage: 20.7 million m3), uses a total of 171 pumps. The following outlines the pump systems.

Keywords
Underground dam, Well pump, Water hammer

ST6 Gas Turbine Cogeneration Facility for Nagano Red Cross Hospital

by Masayuki NISHIMURA, Hitoshi ONO, Hikari SETOGAWA, & Tadashi KONNO

A cogeneration system, comprising two ST6645 kW gas turbine generators and two heat recovery boilers, has been installed at the Nagano Red Cross Hospital. Although this system is primarily designed for normal services, it can also provide electricity in the hospital effectively in emergency situations, such as a stoppage of power from the electric company. Some features of this system are that no cooling water is necessary, that its heat recovery boilers are equipped with bypass ducts, and that auxiliary fans are equipped for ventilation and cooling. Under routine conditions, the two gas turbines are capable of providing 70%-90% of the electricity normally consumed by the hospital. Steam from the heat recovery boilers is used for air conditioning as well as in the hospitals laundry.

Keywords
Cogeneration, Gas turbine, Gas turbine generator, Heat recovery boiler, Hospital, Disaster, Emergency power, Air-cooled, Bypass duct, De-NOx

TIF Fluidized-bed Municipal Waste Incineration System - Incheon International Airport Clean Center -

by Tetsuo SUZUKI, Masaaki FURUKAWA, & Takayoshi HISAMATSU

A TIF type fluidized-bed incineration plant (70 t/d furnaceX2 trains) has been completed in the premises of the new Incheon International Airport in the Republic of Korea. This is the first such plant which was designed and installed by Hyosung EBARA Environmental Engineering Co., Ltd., EBARA CORPORATION's partner in the ROK. The plant incinerates and treats wastes deriving from the airport and its related facilities, as well as municipal waste and sewage in the area. The heat generated in the incinerator is converted into steam which is supplied to an adjacent co-generation facility, thus achieving effective energy recovery. The fluidized-bed incinerator used is a TIF type whose application is attaining excellent feedback in Japan. Dioxin emission is being controlled and satisfies the guaranteed value of 0.1 ng-TEQ/m3 (NTP), a feat attributed to the use of leading-edge pollution prevention technology. The following outlines this plant and its operation.

Keywords
Partnership, Hyosung EBARA, Fluidized-bed incineration, Leading-edge gas treatment system, Sludge mixed combustion, Dioxins, CO.-Generation