Technical informationTECHNOLOGY

VOL.23 NO.1 (published in Jun-2015)

Photo in Cover :Ota Incineration Plant
VOL.23 NO.1 (published in Jun-2015)
Transition of Waste Heat Boilers in TAKUMA


Takuma has supplied more than 450 units of waste heat boilers (WHBs) for many kinds of industrial furnaces and waste incinerators in Japan and overseas since 1952. Differently from ordinary fuel fired boilers, WHBs have certain characteristic which should be specially considered when they are designed. It is also remarkable that the heat source recovered by WHBs has been changing in accordance with the change of the industrial structure. Many WHBs for industrial furnaces were installed in domestic market during the period when heavy industries flourished. Then afterwards, WHBs intended for energy saving, environmental preservation and cogeneration have increased. This paper is to introduce the classification of WHBs based on the type and the structure, their characteristics and the examples which Takuma has supplied to various furnaces and incinerators for domestic and overseas markets.

Boiler Production Technology in Harima Factory
Daisuke YANE*
(*Harima Factory, Manufacturing Section)


Our Harima Factory has a history of 70 years or longer as a production factory for TAKUMA boilers after starting production in 1942. It still produces the products, centering on boiler drums for industrial water-tube boilers. The boilers are the products subjected to high pressures of several MPa. From a viewpoint of securement of safety, various laws, regulations and standards have been strictly stipulated, demanding high quality. Harima Factory takes care of all the processes from marking-off for cutting layout to delivery by itself as to production of the boiler drums and has production facilities and production technologies required for all the processes. This paper describes not only the types of boilers and TAKUMA water-tube boilers, but mainly the boiler drums out of boiler production technologies in Harima Factory. It also refers to the initiatives by the Factory such as skill transfer, quality control and overseas procurement.

Ota Incineration Plant for Clean Authority of TOKYO 23cities-
Features of Plant and Operation Report
(*Environmental Engineering Dept.Ⅰ)


Ota Incineration Plant for Clean Authority of TOKYO 23cities was completed in Sep. 2014, which will serve as a general waste treatment facility. Various performance tests were conducted on this plant during a test run period and all the test items fully satisfied the guaranteed performance. Focusing on "high-efficiency waste power generation," "utilization of natural energy" and "concerns for visitors," this facility features unprecedented ingenuities on those respective points. Particularly, this facility achieved 22.7% power generation efficiency during maximum output of a steam turbine generator and 22.0% power generation efficiency during partial load operation of a steam turbine as to high-efficiency waste power generation, the biggest feature of this feature. Despite use of a wet exhaust gas treatment system which has lower power generation efficiency than a dry exhaust gas treatment, this facility fully satisfied 20% or higher power generation efficiency, which is a requirement for granting a high-efficiency waste power generation facility (Ministry of Environment).

Full-scale Demonstration on High-efficiency Nitrogen Removal Technology by Fixed-bed Type Anammox Process ; Part 4
Keita TAKAKI*,Taro KURUSU*,Tomoyuki Doi*,Kenichi SHISHIDA*
(*Sewerage Engineering Dept.)


Using a full-scale fixed-bed type anammox demonstration plant constructed at Tobu wastewater treatment plant at Kumamoto City, further cost reduction of this process was considered in 2014 after completion of B-DASH (Breakthrough by Dynamic Approach in Sewage High Technology Project) (2012-2013). In a water temperature lower test of a nitritation tank intended for reducing heating fuel, nitritation treatment was stable even if the temperature was lowered from 35 to 30℃ , and the nitrogen removal efficiencies of about 80% ware obtained in the whole process in about 3.5-months continuous operation under steady conditions. In a stop and restart test intended for reducing capacity of an influent regulating tank, operating conditions for stopping this process during a long or short period were established and it was confirmed that the treatment performance was quickly restored after restarting this process.

The Demonstration Study of Power Generation System with Sewage Sludge Incineration ; Part 2
(*Sewerage Engineering Dept.)


This demonstration study was entrusted by National Institute for Land and Infrastructure Management as B-DASH Project. (Breakthrough by Dynamic Approach in Sewage High Technology Project) In this study, we evaluated energy conservation effects as well as cost reduction effects by low-power-consumption incinerators and self-sustained combustion operation, and energy creation effects by power generation, using a demonstration facility constructed in 2013, which has an incineration capacity of 35t-wet/day and a power generation capacity of 100kW. As a result of this study, we achieved three innovative technological goals (water content reduction technology, energy recovery technology and energy conversion technology) and demonstrated power generation from sewage sludge incineration heat at a full-scale level. Based on case study results, it was also confirmed that power consumption of an entire sewage treatment plant could be reduced by about 30%, and maintenance and operation cost and greenhouse gas emissions could be greatly reduced by introducing this system technology into the sewage treatment plant of a certain scale or above. This report describes the operational states and various performances of the demonstration facility in 2014.

Low NOx Combustion by Exhaust Gas Recirculation and Selective Non-catalytic Reduction in MSW Incineration Plant
Hiroki YAMASAKI*1,Munechika ITO*1,Takeshi YASUE*2
(*1Energy and Environmental Development Dept., *2Environmental Engineering Dept.Ⅰ)


High-efficiency waste power generation is strongly demanded from viewpoints of promotion of global warming countermeasures in the waste disposal field and effective utilization of renewable energy. As one of measures, if NOx can be reduced below an exhaust gas regulation value inside the furnace by combustion control and SNCR (Selective Non-Catalytic Reduction) technology, NOx removal in a catalytic reaction tower becomes unnecessary, improving power generation efficiency due to reduction of a steam volume used for an exhaust gas reheater. This time, we have advanced the EGR (Exhaust Gas Recirculation) technology and SNCR technology, and introduced into the MSW (Municipal Solid Waste) incineration plant. With a combination of EGR and SNCR, it was possible to reduce the NOx to 30 ppm (O2=12%, dry) or less. As a result, the catalytic reaction tower was made available for dioxin decomposition, and power generation was improved by reducing an exhaust gas reheating steam volume.

Selective Non-catalytic Reduction (SNCR) Test with Urea Decomposing Device
Masaaki KURATA*,Muneharu FUJIKAWA*,Hiroki FUJIHIRA*,Norio MAEDA*
(*Energy & Engineering Development Dept.)


We developed a system for spraying ammonia inside a furnace as a reducing agent for denitration, obtained through urea decomposition by a catalyst. First, we manufactured a full-scale pilot tester, collected basic data, and confirmed the conditions allowing a conversion rate from urea into ammonia to be 100%. Then, we installed a urea decomposing device in a municipal waste incineration plant to conduct a selective non-catalytic reduction test. As result, we succeeded to reduce consumption of urea water by about 50%, which is a reducing agent for denitration, compared with the existing urea water injection system.