KAMO, Tohru

写真a

Affiliation

Research Council (Research Organization), Research Organization for Nano & Life Innovation

Job title

Senior Researcher(Professor)

Homepage URL

http://www.aist.go.jp/RESEARCHERDB/cgi-bin/worker_detail.cgi?call=namae&rw_id=T18692018

 

Research Areas 【 display / non-display

  • Environmental materials and recycle technology

Papers 【 display / non-display

  • Thermal decomposition of poly(vinyl chloride) in organic solvents under high pressure

    Tohru Kamo

    POLYMER DEGRADATION AND STABILITY   98 ( 2 ) 502 - 507  2013.02  [Refereed]

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    In order to study chlorination of the plastics derived liquid products by secondary reaction of hydrogen chloride, thermal decomposition of poly(vinyl chloride) (PVC) was carried out in decalin or tetralin at 300-460 degrees C for 0-90 min under 4.0 MPa of initial nitrogen pressure. Dechlorination of PVC was completed in 30 min at 300 degrees C, and further slight degradation of the dechlorinated PVC was observed in both solvents. Conversion of PVC to its liquid product proceeded with time at 400 degrees C, and much more liquid product was produced in tetralin than in decalin. In the liquid product, 1,4-dichlorobutane was observed as the dominant organic chlorine product at 300 degrees C, and its yield increased with the reaction time in both solvents. We detected 1,3-dichlorobutane, 1-chlorobutane, 2-chlorobutane, and chlorinated solvents as minor organic chlorine products. These results suggest that 1,4-dichlorobutane is a unique product of the secondary reaction between gaseous hydrogen chloride and the polyene chain derived from the dechlorination of PVC. In decalin, the yield of 1,4-dichlorobutane decreased with temperature, and the maximum yield of chlorodecalin was observed at 400 degrees C. Conversely, yields of all organic chlorine compounds decreased with the reaction time in tetralin, and this hydrogen donorable solvent effectively prevented the production of organic chlorine compounds. (C) 2012 Elsevier Ltd. All rights reserved.

    DOI

  • Influence of mixed molten carbonate composition on hydrogen formation by steam gasification

    Tohru Kamo, Beili Wu, Yuriko Egami, Hajime Yasuda, Hideki Nakagome

    JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT   13 ( 1 ) 50 - 55  2011.02  [Refereed]

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    Steam gasification in the presence of carbonate compounds is an effective method to recover useful materials from electronic waste streams by converting plastics into gaseous products that can be used for energy production and avoiding the expensive manual disassembly process. We investigated steam gasification of activated carbon in the presence of various mixtures of lithium carbonate, sodium carbonate, and potassium carbonate. The activated carbon was almost completely converted into hydrogen and carbon dioxide at 700 degrees C under 0.1 MPa pressure in the presence of carbonate mixtures. Carbon dioxide was also derived from partial decomposition of lithium carbonate. Steam gasification was accelerated in the presence of various carbonate mixtures and at increasing steam partial pressures. These experimental results show that fluidity of carbonates, the potassium content of the carbonate, and the steam partial pressure are important factors in accelerating steam gasification.

    DOI

  • Rapid hydropyrolysis of model compounds for epoxy resin oligomers and biomass tar

    Hajime Yasuda, Tohru Kamo, Mariko Adachi, Satoshi Sajima, Hideki Nakagome

    JOURNAL OF MATERIAL CYCLES AND WASTE MANAGEMENT   12 ( 2 ) 123 - 127  2010.06  [Refereed]

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    The rapid hydropyrolysis of model compounds for epoxy resin oligomers and biomass tar was carried out in a hydrogen atmosphere at 1073 K and 973 K. The assumed oligomers were partially pyrolyzed epoxy resin with biomass tar as solvent for the resin. The product distributions obtained from rapid hydropyrolysis of phenol and bisphenol-A are shown. We also discuss the effects of reaction temperature and hydrogen partial pressure on the product yield. In particular, more phenol was produced from bisphenol-A at 973 K than at 1073 K. The yield of methane, which was the final hydropyrolysis product, increased with increasing hydrogen partial pressure, whereas benzene and phenol were believed to behave as intermediate products in the hydropyrolysis reaction. The results suggest that phenol could be obtained with high selectivity from tar by optimizing the reaction conditions.

    DOI

  • Effect of solvents on the liquid-phase cracking of thermosetting resins

    Y Sato, Y Kodera, T Kamo

    ENERGY & FUELS   13 ( 2 ) 364 - 368  1999.03  [Refereed]

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    The effect of solvents on the liquid-phase cracking of thermosetting resins was examined in the presence of tetralin (hydrogen-donor solvent), decalin (nondonor solvent), or petroleum heavy oil with a reaction time of 60 min at 430-450 degrees C in a 200-mL autoclave under 2 MPa of initial nitrogen atmosphere. Epoxy and novolak-type phenol resins, as typical thermosetting resins, showed almost 100 wt % conversion and about an 85 wt % yield of distillable oil when an iron oxide-sulfur catalyst and tetralin solvent were used. With decalin, the oil yield from epoxy resin decreased to 75 wt %; however, the phenol resin gave an extremely low conversion of 30 wt % with an oil yield of 25 wt %. Cracking of a resol-type phenol resin gave only 9 wt % conversion with decalin but increased to 99 wt % with tetralin. ABS and urethane resin also showed high conversions of more than 90 wt % and oil yields of 60-90 wt % with tetralin. In all experimental runs, gas yields were very low at 1-3 wt %, except for the case of urethane foam in which about 20 wt % of carbon dioxide was produced. In the oil produced from epoxy and phenol resins, 40-74 wt % of phenol compounds were detected. This indicates that liquid-phase cracking proceeds through simple bond dissociation followed by quick hydrogen supply from tetralin without any condensation.

  • Low temperature liquid-phase cracking of low rank coal

    Y Sato, Y Kodera, T Kamo, H Yamaguchi, K Tatsumoto

    PROSPECTS FOR COAL SCIENCE IN THE 21ST CENTURY, VOLS I AND II     705 - 708  1999  [Refereed]

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    Liquid-phase cracking of low rank coal at 350 similar to 440 degrees C under 2MPa of initial nitrogen atmosphere has been studied to produce upgraded coal with high heating value, reducing the tendency to spontaneous ignition. Liquid-phase cracking of Buckskin (USA subbituminous) coal using iron oxide catalyst in the presence of t-decalin at 440 degrees C gave 11.6 wt% of gas, 8.9 wt% of oil and 74.0 wt% of upgraded coal with small amount of water. Gaseous product consisted of mainly carbon dioxide (62 wt%) and methane. Therefore, cracking of carboxylic function took place effectively in these conditions. Heating value of the upgraded coal increased to 7,440 kcal/kg, as compared with 4,610 kcal/kg of untreated coal and the behavior of spontaneous ignition was greatly improved by the liquid-phase cracking. Taiheiyo (Japanese subbituminous) and Yallourn (Australian brown) coals were also studied to produce solid fuel with high quality and useful oil for chemical use.

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Misc 【 display / non-display

  • Production of hydrogen by steam gasification of dehydrochlorinated poly(vinyl chloride) or activated carbon in the presence of various alkali compounds

    Tohru Kamo, Kanji Takaoka, Junichiro Otomo, Hiroshi Takahashi

    Journal of Material Cycles and Waste Management   8 ( 2 ) 109 - 115  2006.09  [Refereed]

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    Steam gasification of dehydrochlorinated poly(vinyl chloride) (PVC) or activated carbon was carried out in the presence of various alkali compounds at 3.0∈MPa and 560°C-660°C in a batch reactor or in a semi-batch reactor with a flow of nitrogen and steam. Hydrogen and sodium carbonate were the main products and methane and carbon dioxide were the minor products. Yields of hydrogen were high in the presence of sodium hydroxide and potassium hydroxide. The acceleration effect of the alkali compounds on the gasification reaction was as follows: KOH &gt
    NaOH &gt
    Ca(OH)2 &gt
    Na 2CO3. The rate of gasification increased with increasing partial steam pressure and NaOH/C molar ratio. However the rate became saturated at a molar ratio of NaOH/C greater than 2.0. © Springer-Verlag Tokyo 2006.

    DOI CiNii

  • Effect of steam and sodium hydroxide for the production of hydrogen on gasification of dehydrochlorinated poly(vinyl chloride)

    T Kamo, K Takaoka, J Otomo, H Takahashi

    FUEL   85 ( 7-8 ) 1052 - 1059  2006.05  [Refereed]

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    Dehydrochlorinated poly(vinyl chloride) (PVC) and activated carbon were pyrolyzed with sodium hydroxide in a flow of steam and nitrogen at 3.0 MPa and 560-660 degrees C. In both cases, hydrogen and sodium carbonate were the main products, and methane, ethane, and carbon dioxide were minor products. The gasification rate increased with partial steam pressure, and the reaction order with respect to steam partial pressure was 0.69. For both dehydrochlorinated PVC and activated carbon, the gasification rate increased with the NaOH/C molar ratio. However, the rate became saturated at NaOH/C ratios higher than 2.0. The activation energy of gasification of dehydrochlorinated PVC or activated carbon was 178 kJ/mol, assuming first-order reaction rate. These experimental results indicate that hydrogen was produced from the reaction: C+2NaOH+H2O -> Na2CO3+2H(2). (c) 2005 Elsevier Ltd. All rights reserved.

    DOI CiNii

  • Effect of hydrogen transferred from solvent and gaseous hydrogen on thermal decomposition of dehydrochlorinated poly(vinyl chloride)

    T Kamo, Y Kodera

    POLYMER DEGRADATION AND STABILITY   87 ( 1 ) 95 - 102  2005.01  [Refereed]

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    Poly(vinyl chloride) (PVC) dehydrochlorinated at 300degreesC was decomposed in tetralin at 440degreesC or 470degreesC for 60min under 7.1 MPa initial pressure of nitrogen or hydrogen or of hydrogen in the presence of a nickel-molybdenum catalyst. A tetrahydrofuran-insoluble fraction, a hexane-insoluble undistilled fraction, a hexane-soluble undistilled fraction, and a liquid product were the main products at both temperatures. At 440 C under nitrogen. the yield of liquid product was 7.1%. but the yield increased to 43.2% under hydrogen in the presence of the catalyst at 470degreesC. Linear relationships were observed between the yieids of the products derived from the dehydrochlorinated PVC and the total amounts of hydrogen transferred from tetralin and gaseous hydrogen. Hydrogen transferred from the solvent and from gaseous hydrogen promoted the degradation of dehydrochlorinated PVC and reduced the amount of residual chlorine in the degradation products. (C) 2004 Elsevier Ltd. All rights reserved.

    DOI CiNii

  • Effects of pressure on the degradation of poly(vinyl chloride)

    T Kamo, Y Kodera, Y Sato, S Kushiyama

    POLYMER DEGRADATION AND STABILITY   84 ( 1 ) 79 - 85  2004.04  [Refereed]

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    Poly(vinyl chloride) was decomposed for 0-90 min at 300-440 degreesC under 0-6.0 MPa of nitrogen pressure. Hydrogen chloride, liquid products, and residue were the main decomposition products. The yield or liquid products decreased with increasing reaction pressure. whereas the yield of residue increased, reaching maxima at 9.8 MPa (400 degreesC) and 22.4 MPa (440 degreesC). The pressure dependences of the product distribution and atomic ratio of hydrogen to carbon (H/C) imply that some of the liquid products were polycondensed with the dehydrochlorinated PVC and were retained in the residue under high-pressure. At atmospheric pressure, benzene was the predominant product. The yield of benzene decreased sharply with pressure, whereas the yield of linear paraffins increased significantly. The liquid product distribution suggests that polyene chains in the dehydrochlorinated PVC were converted to benzene and alkylbenzene under atmospheric pressure. However, some of the polyene chains underwent hydrogenation to form linear paraffins under high pressure. (C) 2004 Elsevier Ltd. All rights reserved.

    DOI

  • Effects of solvent on degradation of poly(vinyl chloride)

    T Kamo, Y Kondo, Y Kodera, Y Sato, S Kushiyama

    POLYMER DEGRADATION AND STABILITY   81 ( 2 ) 187 - 196  2003.08  [Refereed]

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    Poly(vinyl chloride) (PVC) was decomposed in t-decalin and tetralin at 300-460 degreesC under an initial nitrogen pressure of 4.0 MPa. To aid mechanistic discussions, some reactions were also performed in the absence of solvent. In the beginning of the reaction at 300 degreesC, PVC was converted to THF-insoluble dehydrochlorinated PVC (idcPVC) irrespective of the presence of solvent, by liberation of hydrogen chloride. In the reactions without solvent, oil and solid carbon were produced from idcPVC predominantly by degradation and condensation reactions respectively. In the presence of solvent, idcPVC was converted into oil directly or via THF-soluble dehydrochlorinated PVC (sdcPVC). Particularly in tetralin, the decomposition of idcPVC into oil was accelerated significantly over 440 degreesC. A reaction mechanism was discussed using two parameters, atomic ratio of hydrogen and carbon (H/C) and carbon content (C-i). (C) 2003 Elsevier Science Ltd. All rights reserved.

    DOI

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