Minami-rinkan, Japan
Minami-rinkan, Japan

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Noguchi T.,Toyo Koatasu Co. | Noda Y.,Toyo Koatasu Co. | Yamasaki Y.,Hiroshima University | Inoue S.,Hiroshima University | And 4 more authors.
Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy | Year: 2011

Supercritical water gasification is a promising technology to recover energy from wet waste biomass feedstock. To properly design the supercritical water gasification plant, heat transfer characteristics of the heating section is essential. Although the supercritical water has been an object of study for a long time, report on heat transfer characteristics of the flowing biomass slurry feedstock is limited. The purpose of this study is to measure heat transfer characteristics of biomass slurry flowing in the tube. Heat transfer characteristics of the biomass slurry was measured experimentally and correlation was made to predict the heat transfer characteristics. The resulting is applicable only to the biomass slurry tested here, but the procedure developed in this study should be applicable to other kinds of biomass slurry.


Horiguchi N.,Hiroshima University | Inoue S.,Hiroshima University | Kawai Y.,Chuden Plant Co. | Noguchi T.,Toyo Koatasu Co. | And 3 more authors.
Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy | Year: 2013

The heat transfer characterisitcs of activated carbon suspended slurry near the critical point of water was determined experimentally using a double pipe heat exchanger. The preliminary experiment to mea sure the heat transfer coefficient of water showed the value predicted by the previous study. There is hardly any effect of activated carbon addition and change of its concentration. This result suggests that heat transfer of biomass slurry with suspended catalyst powders near the critical point of water can be estimated using the heat transfer characteristics of water, which is of practical importance.


Matsumura Y.,Hiroshima University | Yamashita Y.,Hiroshima University | Inoue S.,Hiroshima University | Kawai Y.,Chuden Plant Co. | And 3 more authors.
10AIChE - 2010 AIChE Annual Meeting, Conference Proceedings | Year: 2010

Supercritical water gasification is a promising technology for the effective use of wet biomass including manures, food wastes, and sewage sludge. The authors have shown that the reaction kinetics in supercritical water gasification with and without activated carbon catalyst can be experessed using Arrhenius type first-order reaction rate. In this study, the reaction paremeters for various biomass species including chicken manure, swine manure, cattle maure, soy-bean hydrogen fermentation residue, food waste hydorgen fermentation residue, waste grass, and seaweed ethanol fermentation residue were determined, and compared. The result showed that the bioamss species can be categorized into some groups in terms of its reactivity in supercritical water and the effect of activated carbon catalyst.


Matsumura Y.,Hiroshima University | Hara S.,Hiroshima University | Kaminaka K.,Hiroshima University | Yamashita Y.,Hiroshima University | And 6 more authors.
Journal of the Japan Petroleum Institute | Year: 2013

Supercritical water gasification is expected to be an effective gasification process for wet biomass, but its reaction kinetics has not been elucidated for actual biomass feedstocks. In this study, seven biomass species are gasified in a supercritical water gasification reactor with and without use of a suspended activated carbon catalyst, and the overall gasification rates are determined. The feedstocks can be classified into three groups depending on the gasification characteristics. Representative gasification-rate parameters are presented. The homogeneous reaction had a pre-exponential factor of 50.0 s -1 and an activation energy of 67.9 kJ/mol. The heterogeneous reaction for feedstocks with high cellulose content had a pre-exponential factor of 4.87×109 s-1 and an activation energy of 161 kJ/mol, while, feedstocks with low cellulose content had a pre-exponential factor of 1.91× 104 s-1 and an activation energy of 84.2 kJ/mol.


Noguchi T.,Toyokoatsu Co. | Noda Y.,Toyokoatsu Co. | Yamasaki Y.,Hiroshima University | Inoue S.,Hiroshima University | And 4 more authors.
Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy | Year: 2011

The rheological characterisitcs of biomass slurry was determined from the pressure drop under high temperature and high pressure, using chicken manure. The dependence of the pressure drop on the flow rate was used to distinguish laminar and turbulent flow. The n-th order model was employed, and parameters in the model were determined to reproduce the experimental results. Surprisingly, the flow was well expressed with the Newtonian model where n=1, which contradicts with the previous study using the rotating viscometer. The difference in the sheer rate is expected to be the cause of this difference. The apparent viscosity reduced with temperature rise, and agrees with that of water above 300 C for the slurry employed here. The methodology employed here is simple, and can be employed to determine the rheological characteristics of various slurries.


Wada Y.,Chugoku Electric Power Co. | Oyama K.,Chugoku Electric Power Co. | Yamasaki T.,Chugoku Electric Power Co. | Uchiyama I.,Chugoku Electric Power Co. | And 6 more authors.
Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy | Year: 2013

The operation of a 1 t-wet/d supercritical water gasification plant was evaluated for the gasification of barley shochu residues with activated carbon charges ranging from 0 to 0.05 kg/kg-slurry. Activated carbon concentrations greater than 0.025 kg/kg-slurry were found to prevent plugging by tarry residues. The pressure loss for the effluent that flowed in the annulus of the double-tube heat exchanger did not exceed 0.2 MPa. Long continuous operation times of 17 h 48 min were possible with an activated carbon charge of 0.025 kg/kg-slurry. Activated carbon is not only effective for prevention of plugging, but also effective for reduction in total organic carbon and enhancement of carbon gasification efficiency. An economic evaluation showed that the process can be viable when operated for more than 200 d per year.


Hirota S.,Hiroshima University | Inoue S.,Hiroshima University | Inoue T.,Fukken Co. | Kawai Y.,Chuden Plant Co. | And 3 more authors.
Korean Journal of Chemical Engineering | Year: 2016

Supercritical water gasification (SCWG) has attracted attention as a technology for utilizing wet biomass. We used a fluidized bed of alumina particles to prevent blockage of a SCWG reactor. A glucose solution was heated in the reactor with and without fluidized alumina particles. In the absence of alumina particles, char particles formed homogeneously in the reactor, but the use of a fluidized bed resulted in accumulation of char particles at the reactor’s exit rather than inside the reactor. Therefore, the fluidized bed was effective at preventing blockage of the reactor. However, the alumina particles did not remove deposits from the reactor’s walls. Instead, the fluidized bed caused larger char particles to form, preventing their adhesion to the reactor’s wall. © 2015 Korean Institute of Chemical Engineers, Seoul, Korea


Samanmulya T.,Hiroshima University | Inoue S.,Hiroshima University | Inoue T.,Fukken Co. | Kawai Y.,Chuden Plant Co. | And 3 more authors.
Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy | Year: 2014

The gasification characteristics of five amino acids, i.e., glycine, alanine, valine, leucine, and proline, in supercritical water were compared. A tubular reactor was employed for the gasification reactions in the temperature range of 500 to 650 °C with a reaction pressure of 25 MPa and residence time of 86-119 s. The gasification characteristics of glycine, alanine, and leucine were determined to be similar, while the gasification rate of valine was much slower. The activation energies of valine and proline were lower than those of glycine, alanine, and leucine. These behaviors are attributed to the stability of the transition state for carboxyl radical production and secondary radical produced from valine.


Samanmulya T.,Hiroshima University | Inoue S.,Hiroshima University | Inoue T.,Fukken Co. | Kawai Y.,Chuden Plant Co. | And 3 more authors.
Journal of the Japan Petroleum Institute | Year: 2014

Alanine solution (1.0-3.0 wt%) was gasified in supercritical water using a tubular reactor at a temperature of 500 to 650°C and a pressure of 25 MPa for a residence time of 86-119 s and compared the gasification characteristic with our previous work, glycine. The identification and quantification of gaseous products were conducted by gas chromatography (GC) and the total organic carbon (TOC) in the aqueous phase was also determined. The carbon gasification efficiency of alanine rose with increasing reaction temperature and the gasification rate followed first order kinetics. It was well expressed with the Arrhenius equation. The gasification rate of alanine was identical to that of glycine. The effect of the methyl group in alanine is the production of methane and the dilution of nitrogen so that the alkaline effect is suppressed. The former explains the higher methane yield, and the latter results in a high carbon monoxide yield. © 2014, Japan Petroleum Institute. All rights reserved.

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