[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

An incineration process is the most dominant method of the waste disposal in Japan. A stoker furnace is widely used for the waste incineration. Recently, in the stoker furnace, low air ratio and high temperature incineration have been applied increasingly. However, they result in the increase in the amount of air pollutant NOx and greenhouse gas N₂O generated due to flame instability. In this research, in order to clarify the NOx generation mechanisms in the waste incineration, RDF burning experiments were carried out, investigating the combustion behaviors and exhaust gas compositions. Mass reduction of RDF proceeded faster with higher temperature. NOx concentration in exhaust gas was found to decrease with increase in temperature. It might result from the strong reduction atmosphere generated around RDF fuel. In addition, RDF burning simulation was carried out, using elemental reaction kinetics. It was found that most of HCN and NH₃ at high temperature was converted to NO, N₂O and N₂.

View full abstract

[in Japanese]

View full abstract

Because a large portion of chemical substances used for materials and products is eventually discarded and processed as waste, managing chemical substances during waste treatment processes is an important part of risk reduction throughout their lifecycle. Quantitative information of the flows and environmental emission of chemical substances is a basis for a better chemical management; however, such information is still insufficient for waste treatment. This study estimated and analyzed the metal content of incinerated industrial waste in Japan based on experimental analysis of incineration residue samples. The results showed that several waste categories are predominant in the inflows of chemical substances undergoing industrial waste treatment. For example, sludge, waste acid and waste alkali predominate the inflows of metals to industrial waste incineration processes. To better manage metal flows and emission during waste treatment processes, it is important to understand the behavior and emission of chemical substances at facilities that are processing mainly these waste categories.

View full abstract

Heavy metals concentration in fly ash and relation between the concentration and incinerated industrial wastes are analyzed for estimation of chemicals emission from industrial wastes incineration facilities. The concentration of heavy metals in fly ashes was different widely, however, compositions of each metal were similar except a few facilities. In the relation analysis of the concentration and incinerated industrial wastes, sevaral specific wastes such as waste oil and waste acid/alkari are cosidered to raise the concentration of heavy metals in fly ash. It is also suggeted that some wastes raise some specific metal concentrations in fly ash. For example, lead will be related to the incinerated amount of waste wood and specially controled sludge.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

In the Stockholm Convention on persistent organic pollutants, characteristics of persistent organic pollutants are shown in consideration of international regulations, standards, guidelines, etc. concerning waste containing regulated substances (hereinafter referred to as POPs waste) We are demanding that POPs be disassembled so that they will disappear. In domestic POPs waste disposal, PCB is designated as PCB Special Measures Law and dioxins as special controlled industrial waste based on the Law Concerning Special Measures against Dioxins. However, disposal of agricultural chemicals, PFOS , PCN, other POPs waste such as brominated flame retardant are required to confirm that the decomposition rate is 99.999% or more beforehand by technical considerations, but there is no legal binding force in the present situation .


However, based on legislation in Japan in the future, we have carried out a demonstration test using various POPs waste at the waste incineration facility within our group. In this report, we report the results of the demonstration test.

View full abstract

Bag filter has high particle collection efficiency and are widely used in the industry as a dust collector for purifying dust containing exhaust gas. The pressure drop of the dust collector is mainly due to the pressure drop due to the filtered air flow, and the collected particles are cleaned by vibrations, reverse air currents, etc., thereby suppressing the rise in the pressure drop and enabling long-term use. Here, the effect of the fabric structure constituting the felt type bag filter on the reduction of the dust collection pressure drop was paid out and experimentally examined based on the dust cleaning mechanism, and three findings were obtained. ① The filter stretching degree decreases as the fabric crossing angle increases. ② The pressure drop of filtration decreases as the fabric crossing angle increases. ③ The dust concentration at outlet of dust collector decreases as the fabric crossing angle increases.
Currently, in the case of actual operation, compared with the conventional product, the product made by crossing angle of 90 degrees is about twice as long as the filter pressure drop, and we aim to contribute to many industrial applications in the future.

View full abstract

We studied effects of ordinary slaked lime(OSL) and highly reactive slaked lime(HRSL) on HCl reduction using an experimental bag filter(BF), which the branched flue gas was passed through. When HCl at the BF outlet was targeted at 10ppm, which may be attained with a wet gas treatment, the required equivalent ratio(RER) of OSL was 4.0. Although this value was considerably larger than 1.3 that was for the HCl target of 30ppm, accompanying the fly ash recirculation (FAR) reduced the RER to 2.2. These results show that OSL injection should be accompanied by FAR when HCl at the BF outlet is targeted at 10ppm.
Whereas, we found that even for the HCl target of 10ppm, the RER of HRSL was 1.4, hence FAR was unnecessary.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

We developed a multizonal thermodynamic equilibrium calculation model to estimate the fate of ash-forming elements in solid waste incineration plants. This model divides processes of an incineration plant into three steps, (1) incineration of combustible waste and reactions of ash-forming elements, (2) high-temperature reactions of flue gas and additives in a combustion chamber, and (3) flue gas cooling/cleaning processes. In each step, equilibrium composition was calculated using a commercial thermodynamic equilibrium calculation software (ChemSheet, GTT-technologies), and by multiplying the conversion efficiency, the product composition of the step was estimated and that was used in the next steps as their inlet compositions. In this study, we modified the model to estimate the fate of heavy metal in a lab-scale RDF incineration plant and 2 industrial waste incineration plants, to evaluate the accuracy of the calculation. The relative difference between the calculated and measured elemental distributions among the incineration residues were within 20 % for Cd, Cr, Mn, Se, Pb, Ni, V, Be, and B, and 25 % for Sn and As, indicating that this calculation can be used in the estimation of fate of 12 inorganic substances regulated by PRTR (pollutant release and transfer register).

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

We report on a solution for two main challenges. One is the challenge to achieve cost effective recycling technology for incineration residue. The other is to use the plastic which is not suitable for material recycle (MR).

KUBOTA Surface Melting Furnace (KSMF) is a fuel type melting furnace which can treat various kinds of wastes such as incineration ash, sewage sludge, landfill waste (mixture of combustible and incombustible wastes). We have the solution to these two challenges at the same time by using plastics as fuel for ash melting.

We have verified the fuel reduction effect by using waste plastic fuel in a commercial ash melting plant (15.5 t-ash/day) at Urasoe City Clean Center. We used the plastics originated from WEEE which are not suitable for MR. In case of feeding the plastics with incineration ash at mixture rate of 12wt%, fossil fuel consumption rate was reduced by 32% compared to the conventional operation without plastics. On the other hand, the throughput of ash did not decrease.

As the result of feasibility study based on the verification test, a plastic receiving and supplying facility was introduced to this plant. The operation using waste plastic began in December of 2017.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

Fly ash containing radioactive cesium (Cs) was designated as "specified waste" and currently is stored in interim storage site. Cs in the fly ash is high in concentration, but because most of them is a chloride, it is highly soluble and has high mobility. Alkali feldspar, when heated to 700 to 900 °C in the coexistence with Cs, captures Cs in the amorphous phase formed on the surface and makes it insoluble. In this study, it was examined experimentally whether or not this Cs trapping mechanism occurs even in the presence of fly ash. Alkali feldspar used for ceramic industry or alkali feldspar synthetic material were added to simulated fly ash, which was prepared by adding Cs, at various ratios and then the mixture was heated. In case of the alkali feldspar, the ratio of Cs captured in the feldspar was increased by amorphizing the feldspar. However, when fly ash mixed, the trapping rate decreased. When the sol reagent which is an alkali feldspar synthesis material was used, about 90% of Cs contained in fly ash was trapped and became insoluble state by addition of 4 times the fly ash amount.

View full abstract

[in Japanese]

View full abstract