In this study, we investigated the configuration and operating conditions of a CO₂ methanation process using a multi-stage catalytic reactor toward CO₂ methanation process capable of supplying natural gas to the grid. By removing water from the outlet of the first-stage reactor, setting the H₂/CO₂ molar ratio at the inlet of the second-stage reactor to 3.9, and the temperature of the second-stage reactor to 260–280°C, the CO₂ conversion rate of the entire reactor reached over 98%. In addition, a PROX catalytic reactor was installed in the final stage to oxidize and remove CO sufficiently as a byproduct, and it was found that the outlet gas composition met the natural gas grid supply standard while maintaining the CH₄ production rate. This study was able to demonstrate the basic configuration of a CO₂ methanation system based on a system that combines two-stage and final-stage gas purification.

The objective of this paper is to establish a classification evaluation method considering the effect of specific gravity sorting in air classification. A sample of fine particle group (0.063 mm or less) of photovoltaic panel cell sheet crushed was used as a representative sample of the multi-component ground product. The sample was classified into three groups using an elbow-jet classifier, and the resulting coarse, medium, and fine fractions were subjected to XRF chemical component analysis, SEM image analysis, and particle size distribution measurement. From the results, it was confirmed that a part of the particle size range was reversed between the coarse and medium fractions. This is because the photovoltaic panel cell sheet ground product is multi-component, which is affected by the difference in specific gravity of each component. Silver particles with high specific gravity were more likely to distribute in the coarse fraction area, and resin particles with low specific gravity were vice versa. The results of the three-point sorting of coarse, medium, and fine fractions were modified to the two-point sorting of coarse and fine fractions, and the effect of specific gravity sorting was quantitatively evaluated using the specific gravity sorting efficiency and the absolute specific gravity sorting efficiency. The apparent specific gravity sorting efficiency is a value indicating the reversal ratio of the particle size range between coarse and fine fractions. The absolute specific gravity sorting efficiency is an inherent value that expresses the effect of specific gravity sorting of the raw powder, and this value can be used to predict the classification results.

In this study, a numerical analysis of methane/ammonia co-combustion was conducted by using the experimental data owned by Tokyo Gas Co., LTD. A reduced reaction mechanism was developed to calculate a relatively large model such as an industrial furnace, and some parameters-tuned turbulent combustion model (EDC) was used to reproduce the experimental results in general. NOx concentrations in the furnace were predicted accurately when the ratio of primary air to secondary air was varied, and when the ammonia mixing ratio was varied during one-stage and two-stage combustion, respectively. On the other hand, when D₂ was varied, NOx concentrations tended to be overestimated at D₂=11 mm compared to the experimental results. The calculation time for all conditions was about one day on a bench-top workstation, which is significantly shorter than the time required for the existing detailed reaction mechanism. As a result, design guidelines for the development of industrial ammonia combustion burners that take advantage of the combustion characteristics of ammonia can be obtained in a very short time, which is expected to lead to more efficient equipment design. We developed a reduced reaction mechanism for methane/ammonia co-combustion and optimized the parameters of a turbulent combustion model (EDC) incorporating this reaction mechanism. This has made it possible to predict the NOx emission characteristics of an industrial furnace with high accuracy.

We report a novel method for the synthesis of silver nanowires (AgNWs). In this method, silver chloride (AgCl) and N, N-dimethyl-dodecylamine hydrochloride (C₁₂H₂₅NMe₂·HCl) are used as a silver source and a protecting agent, respectively. Heating of both reagents in N, N-dimethyldodecylamine forms silver chlorocomplex, AgCl _n^{1– n} solving homogeneously in the melting C₁₂H₂₅NMe₂·HCl. The addition of the reducing agent, N, N-dibenzylhydroxyamine to the reaction mixture in order to reduce AgCl _n^{1– n} to silver atom (Ag⁰) gives firstly multiplied twinned nanoparticles (MTPs), and then uniform silver nanowires (AgNWs) with the dimension of 50–100 nm in thickness and >20 µm in length. Thermogravimetric analysis of the product reveals that highly pure AgNWs containing less organic residues are obtained. We investigate the effects of loading ratios of tertiary amine hydrochlorides to AgCl, the molecular structures of amines, and reaction temperature on the morphologies and yields of the generated AgNWs. We demonstrate that the MTPs are efficiently generated by the reduction reaction of AgCl _n^{1– n} in the presence of tertiary amine hydrochlorides, and that tertiary amine hydrochlorides also play an important role in anisotropic crystal growth of Ag⁰ to AgNWs through the formation of the MTPs.