Junya Nishino

Acceleration of cellulose co-pyrolysis with polymer

Abstract This study was conducted for greater clarification of pyrolysis of municipal solid waste. The pyrolysis of pure cellulose, polyethylene (PE), polypropylene (PP), polystyrene (PS), poly(vinyl chloride) (PVC), and poly(vinylidene chloride) (PVdC) was compared with that of mixtures of these compounds by thermal analysis. Interaction only between cellulose and PVC or PVdC was confirmed. The mechanism of pyrolysis of a mixture of cellulose with PVC was also studied. Acceleration of dehydration and production of aldehyde compounds was observed to occur temporarily with the dehydrochlorination of PVC by thermogravimetry–direct mass spectrometry (TG–MS). FT–IR analysis indicated the char of a mixture of cellulose and PVC to have fewer hydroxyl groups and more C=O and C=C bonds compared with the char of pure cellulose. HCl evolution from chlorinated polymer may thus possibly induce reactions of dehydration, scission in intra-ring of glucose unit, cross-linkage and charring rather than the depolymerization of cellulose.

Correlation of PCDD/PCDF and CO values in a MSW incinerator––indication of memory effects in the high temperature/cooling section

The correlation of PCDD/PCDF levels with the CO emissions in a full-scale municipal waste incinerator was assessed during a four-week measurement effort. PCDD/PCDF concentrations in fly ashes-containing more than 99% of the total PCDD/PCDF burden of the fluidized bed incinerator (FBI)-were measured and compared with the emitted CO concentrations. The CO concentration during the sampling time showed no significant correlation to the PCDD/ PCDF amount in fly ash (R2 = 0.078). However, a comparison of the time integrated CO concentration several hours before sampling lead to a correlation with the PCDD/PCDF burden. Maximum correlation was found for the time integrated CO values of 3 and 4 h before sampling (R2 = 0.467 and R2 = 0.457 respectively). This indicates a memory effect in the high temperature cooling section of several hours. Possible mechanisms leading to the memory effect are discussed. The correlation of PCDD/PCDF with CO concentration demonstrate that the combustion conditions play an important role for PCDD/PCDF formation in FBIs. However the variability in the correlation of CO to PCDD/PCDF levels show that other factors have a significant influence on PCDD/PCDF formation.

Relevance of coplanar PCBs for TEQ emission of fluidized bed incineration and impact of emission control devices.

Five fluidized bed incinerators combusting municipal solid waste were assessed for the impact of coplanar PCBs on total TEQ emission. In 17 stack measurements, the coplanar PCBs contributed on average less than 3% to total TEQ with a maximum contribution of 7.5% to total TEQ in one measurement. Differences in the design of the flue gas cooling section did not show an effect on the impact of coplanar PCBs on total TEQ. The effect of emission control devices on the impact of coplanar PCBs on the total TEQ was studied in more detail at one incinerator. The relative contribution of PCBs to total TEQ increased along the flue gas line. This was caused by a slightly higher removal efficiency for TEQ relevant PCDDs/PCDFs compared to coplanar PCBs by the bag filters and a higher destruction efficiency for PCDDs/PCDFs compared to PCBs by the SCR catalyst. Additionally, the removal efficiencies of the emission control devices (bag filters and catalyst) for other chlorinated aromatic compounds which have been proposed as TEQ indicator compounds (polychlorinated benzenes and polychlorinated phenols) were compared with those for PCDDs/PCDFs and coplanar PCBs. Removal efficiencies for polychlorinated benzenes or polychlorinated phenols considerably differed from those of PCDD/PCDF and coplanar PCBs. Implications for TEQ assessments using indicator compounds as proposed in the literature are discussed.

Preparation of Superconducting Thick Films of Bi-Sr-Ca-Cu-Oxide Using Plasma Spraying Method under Ambient Pressure

The system using plasma spraying of chemical solution in low power has been used to prepare superconducting Bi2Sr2Ca1Cu2Ox films under ambient pressure. Film as deposition on SrTiO3(100) gave Tc(onset) of 80.0K, Tc(R=0) of 72.6K. And the morphology of the film as deposition was that grain like crystal was grown. On two kinds of substrates was possible to prepare films which had good superconducting properties and morphology, in spite of high rate (1–2μm/hr) for deposition under ambient pressure.

Preparation for Superconducting Thick Films of Y-Ba-Cu Oxide Using Plasma Spraying Method in Low Power under Ambient Pressure

Preparation of thick films using plasma spraying of chemical solution in low power(1.5kW) was studied to give YBa2Cu3O7-х superconducting materials under ambient pressure.

Fabrication of Thick Films of YBa2Cu3Ox Superconductors Using Fine Particles Prepared by Mist Pyrolysis Method

Fine powders of Y-Ba-Cu oxide superconductor were prepared by mist pyrolysis process. Thick films were fabricated by deposition of the powders on MgO(100) substrate. Using Ag as a buffer layer could give the texture with c-axis of 123 phase perpendicular to the surface and sharp superconducting transition(Tc=80K, Jc=1.8×104A/cm2 at 65K) after sintering in Ar flow at 1323K followed by O2 annealing under 1073K.