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ABSTRACT: This study investigates the application of a radio-frequency-powered plasma with a Pt/γ-Al<sub>2</sub>O<sub>3</sub> catalyst to decompose the chlorinated volatile organic compound of vinyl chloride (VC) in air. The use of an atmospheric-pressure plasma jet is explored as an innovative technology for the treatment of VC. The effects of some major system parameters such as input power ( P <sub>WI</sub>), plasma energy density, initial concentration of VC ( C <sub>0</sub>), and space velocity (SV) of the catalyst on the plateau temperature ( TP ) of a reactor and conversions of VC ( X <sub>VC</sub>) are studied and elucidated. The results show that the effectiveness of the plasma-assisted catalysis is evident as indicated by the increase of X <sub>VC</sub> and the rate constant. At a P <sub>WI</sub> of 250 W without a catalyst, the values of X <sub>VC</sub> were 14% and 5.4% for C <sub>0</sub> = 200 and 450 ppmv, respectively. In the presence of the Pt/γ-Al<sub>2</sub>O<sub>3</sub> catalyst with an SV of 17 400 h<sup>-1</sup>, the values of X <sub>VC</sub> for C <sub>0</sub> = 200 and 450 ppmv increased to 49% and 39%, respectively. Note that the values of TP were 550 K and 430 K without and with the Pt/γ-Al<sub>2</sub>O<sub>3</sub> catalyst at an SV of 17 400 h<sup>-1</sup> and a P <sub>WI</sub> of 250 W. The proposed kinetic models describe the relationships of C / C <sub>0</sub> with the major parameters for the plasma and plasma-assisted catalytic degradation of VC, showing good agreement with the experimental data. The information obtained is useful for the operation, design, and analysis of plasma devices.
IEEE Transactions on Plasma Science 05/2011; · 1.17 Impact Factor
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ABSTRACT: The pyrolysis of polyvinyl chloride (PVC) was examined with a thermal gravimetric analyzer (TGA). The experiments were carried out over the temperature range of 400-800 K at three heating rates of 1, 2, and 5.5 K/min and in a nitrogen atmosphere. The results indicate that the entire process of PVC pyrolysis under the experimental conditions of this investigation consists of two distinct pyrolysis stages, namely, the thermal dehydrochlorination and the breakdown of the intermediate products produced after the dehydrochlorination stage. The corresponding activation energy, pre-exponential factor, and reaction order were determined. A two-stage pyrolysis model, which is composed of four reactions including a number of independent, consecutive and competitive reactions with volatiles and solid products, was developed. This kinetic model gives good agreement with the experimental results.On a étudié la pyrolyse du chlorure de polyvinyle (PVC) à I'aide d'un analyseur thermogravimétrique (TGA). Les expériences ont été menées pour une vaste gamme de températures de 400 à 800 K à trois taux de chauffage, soit 1, 2 et 5,5 K/min, en milieu azoté. Les résultats indiquent que le processus de pyrolyse du PVC dans ies conditions expérimentales de cette étude comprend deux étapes distinctes de pyrolyse, à savoir la déshydrochloruration thermique et la fracturation des produits intermédiaires produits aprés l'étape de déshydrochloruration. On a détenniné l'énergie d'activation, le facteur pré-exponentiel et l'ordre de réaction correspondants. Un modéle de pyrolyse en deux étapes comportant quatre réactions dont plusieurs réactions indépendantes, consécutives et compétitives avec des produits volatils et solides, a été mis au point. Les prédictions de ce modéle cinétique concordent bien avec les résultats expérimentaux.
The Canadian Journal of Chemical Engineering 03/2009; 72(4):644 - 650. · 0.75 Impact Factor
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ABSTRACT: Oil sludge is one of the major industrial wastes that needs to be treated for the refinery or petrochemical industry. Efforts have been made to convert the oil sludge into available resources such as lower molecular weight organic compounds and carbonaceous residues. In this study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in northern Taiwan is used as the raw material of thermal treatment using oxygen-containing gas. The treatment of oil sludge is conducted by the use of carrier gas with different concentrations of oxygen (4.83, 8.62, 12.35, and 20.95 vol % O 2) in the temperature range of 380-1123 K and at various constant heating rates of 5.2, 12.8, and 21.8 K/min. The significant reactions occur in the range 415-931 K. Below a temperature of 613 K, pyrolysis reactions are predominant. Including the pyrolysis reactions, the overall oxidative thermal decomposition of oil sludge can be adequately described by a five-parallel-reaction model. The activation energies (E), reaction orders (n for residual solid and m for oxygen) and frequency factors (A) of corresponding five-parallel-reaction model for oil sludge are 69.93, 93.79, 123.22, 208.67, and 120.87 kJ/mol of E, 2.94, 2.42, 1.24, 2.91, and 1.36 of n, 0, 0, 0, 2, and 0.32 of m, and 7.69 × 10 5 , 9.09 × 10 6 , 2.95 × 10 8 , 1.66 × 10 17 , and 9.45 × 10 7 1/min of A, respectively. The proposed reaction kinetic equations can provide useful information for the proper design of an oxidative thermal processing system for the treatment of oil sludge.
Energy Fuels. 01/2004; 18:1272-1281.
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ABSTRACT: Previous efforts were made to convert the oil sludge into useful resources such as lower molecule organic compounds and carbonaceous residues by pyrolysis with the carrier gas of N2. The liquid products (condensates of gases at 298 K) obtained from the pyrolysis of oil sludge are close to diesel oil. However, they contain a significant amount of vacuum residues of about 9.57 wt %, which decrease the qualities of liquid products. In the present study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in the northern Taiwan is used as the raw material for the pyrolysis. The influences of using inexpensive and nonharmful additives on the possible improvement of the pyrolysis of oil sludge are investigated. The additives employed include two groups: (1) aluminum compounds (Al, Al2O3, and AlCl3), and (2) iron compounds (Fe, Fe2O3, FeSO4·7H2O, FeCl3, and Fe2(SO4)3·nH2O). For the increases of conversion X, the additives provide the offers on the order of Fe2(SO4)3·nH2O > Fe2O3 > AlCl3 > FeSO4·7H2O > Al2O3 > FeCl3 > Al > Fe > no additives. It appears that the above additives enhance the reaction rates r when the temperatures T are in 650−710 K, following the orders AlCl3 > Al > Al2O3 > no additives, and Fe2O3 Fe2(SO4)3·nH2O > FeCl3 Fe FeSO4·7H2O > no additives at 710 K. The additives achieve the improvement of the quality q of the oil of pyrolysis (as sum of light and heavy naphtha and light gas oil) on the order of Fe2O3 > Fe2(SO4)3·nH2O > no additives > Al > FeSO4·7H2O > Al2O3 > Fe > FeCl3 > AlCl3. Nevertheless, the additives improve the liquid yields Y on the order of Al > Fe2(SO4)3·nH2O > Fe > Fe2O3 > FeCl3 > no additives > AlCl3 > FeSO4·7H2O > Al2O3. All this information is useful not only to the improvement of a pyrolysis system but also to the better utilization of liquid oil products.
12/2001;
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ABSTRACT: Oil sludge, if unused, is one of the major industrial wastes that needs to be treated for the refinery or petrochemical industry. It contains a large portion of combustible components with high heating values. Obviously, the conversion of oil sludge to various useful materials such as lower molecular weight organic compounds and carbonaceous residue via pyrolysis not only solves the disposal problem but also matches the appeal of resource utilization. In this study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in northern Taiwan is used as the raw material of pyrolysis. Its heating value of dry basis and low heating value of wet basis are about 10681 and 5870 kcal/kg, respectively. The pyrolysis of oil sludge is conducted by using nitrogen as carrier gas in the temperature range 378−873 K. The pyrolytic reaction is complex and significant in the range 450−800 K. The residues of pyrolysis of oil sludge exhibit very high viscous form below 623 K (pyrolysis temperature), while low viscous or solid form above 713 K. The major gaseous products (noncondensable gases at 298 K) excluding N2 are CO2 (50.88 wt %), HCs (hydrocarbons, 25.23 wt %), H2O (17.78 wt %), and CO (6.11 wt %). The HCs mainly consist of low molecular weight paraffins and olefins (C1−C2, 51.61 wt % of HCs). The temperature corresponding to the maximum production rate of HCs is 713 K. The distillation characteristics of liquid product (condensate of gas at 298 K) from the pyrolysis of oil sludge is close to diesel oil. However, it contains a significant amount of vacuum residue of about 9.57 wt %. The heating value of liquid product is about 10840 kcal/kg. All this information is useful not only to the proper design of a pyrolysis system but also to the better utilization of liquid oil product and understanding of gaseous emission.
10/2000;
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ABSTRACT: Oil sludge, if unused, is one of the major industrial wastes requiring treatment from petroleum refinery plants or the petrochemical industry. It contains a large amount of combustibles with high heating values. The treatment of waste oil sludge by burning has certain benefits; however, it cannot provide the useful resource efficiently. On the other hand, the conversion of oil sludge to lower molecular weight organic compounds by pyrolysis not only solves the disposal problem but also has the appeal of resource utilization. The major sources of oil sludge include the oil storage tank sludge, the biological sludge, the dissolve air flotation (DAF) scum, the American Petroleum Institute (API) separator sludge and the chemical sludge. In this study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in northern Taiwan is used as the raw material of pyrolysis. Its heating value of dry basis and low heating value of wet basis are about 10681 kcal kg−1 and 5870 kcal kg−1, respectively. The removal of the moisture from oil sludge significantly increases its heating value. The pyrolysis of oil sludge is conducted by the use of nitrogen as the carrier gas in the temperature range of 380–1073 K and at various constant heating rates of 5.2, 12.8 and 21.8 K min−1. The pyrolytic reaction is significant at 450–800 K and complex. For the sake of simplicity and engineering use, a one-reaction kinetic model is proposed for the pyrolysis of oil sludge, and is found to satisfactorily fit the experimental data. The activation energy, reaction order and frequency factor of the corresponding pyrolysis reaction in nitrogen for oil sludge are 78.22 kJ mol−1, 2.92 and 9.48 × 105 min−1, respectively. For precise use, the two- and three-reaction models are proposed to describe the pyrolysis results. Among the three models proposed, the three-reaction model gives the best fit. These results are very useful for the proper design of the pyrolysis system of the oil sludge under investigation.© 2000 Society of Chemical Industry
Journal of Chemical Technology & Biotechnology 06/2000; 75(6):443 - 450. · 2.17 Impact Factor
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ABSTRACT: The pyrolysis kinetics of a mixture of the four principal papers (uncoated and coated printing/writing papers, newsprint, and tissue paper) in municipal solid waste (MSW) was investigated with a thermal gravimetric analysis (TGA) reaction system. The experiments were carried out in a nitrogen environment over the temperature range of 450 to 900 K at various constant heating rates of 1, 2, and 5 K min−1. The results indicated that there were two principal reactions in the TGA curves as distinguished by the two significant and distinct mass changes over the experimental conditions. The pyrolysis of a paper mixture can be adequately described by a two reaction model. The effect of interaction between the components of a paper mixture on the pyrolysis rate was insignificant. The results for the pyrolysis rates of paper mixtures with slow heating rates can be represented by the weighting sum of the corresponding pyrolysis rates of the components of papers in MSW. The experimental results were satisfactorily fitted by the proposed chemical reaction kinetic equations and able to provide useful data for the design of a pyrolytic processing system for the waste papers in MSW. © 1997 SCI.
Journal of Chemical Technology & Biotechnology 03/1999; 68(1):65 - 74. · 2.17 Impact Factor
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ABSTRACT: The pyrolysis kinetics of commercial-grade styrene–butadiene rubber (SBR), which is one of the major constituents of tyre rubber as well as one of the principal products of the rubber industry in Taiwan, was investigated by a dynamic thermogravimetry (TG) reaction system in a nitrogen atmosphere over the temperature range of 400 to 950 K at the nominal heating rates of 3, 5 and 7 K min−1. The experimental results indicated that the pyrolysis of SBR may be attributed to three reactions, with three distinct mass change characteristics in the mass-loss curves of reactant deduced from the experiments. The corresponding activation energies, frequency factors and reaction orders of the three reactions were determined. A simplified three-reaction model based on the mass-loss curves of reactant was also proposed for engineering purposes. Satisfactory agreements between the proposed model and the experimental results were obtained. The results of this study are useful for the utilization of scrap SBR as an energy resource.
Journal of Chemical Technology & Biotechnology 03/1999; 66(1):7 - 14. · 2.17 Impact Factor
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Journal- Chinese Institute of Engineers 07/1994; 17(5):659-669. · 0.29 Impact Factor
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ABSTRACT: Previous efforts have been made to convert the oil sludge into useful resources such as lower molecule organic compounds and carbonaceous residues by pyrolysis. The liquid products are close to diesel oil; however, they contain a significant amount of vacuum residues, which decrease the qualities of liquid products. For the reuse, conservation and recycling of solid wastes, the effects of using fly ash, oil sludge ash, waste DAY-zeolite and waste polymer of polyvinyl alcohol (PVA) as additives on the possible improvement of the pyrolysis of oil sludge were investigated. For the increase of conversion (X), two weight ratios of 10 and 5 wt.% additives provided the offers in the order of fly ash of 10 wt.% > PVA of 10 wt.% > oil sludge ash of 10 wt.% > DAY-zeolite of 10 wt.% > fly ash of 5 wt.% > DAY-zeolite of 5 wt.% > no additives. The addition of additives achieved the improvement of the quality (q) of pyrolysis oil (as sum of light and heavy naphtha and light gas oil) in the order of fly ash of 10 wt.% > oil sludge ash of 10 wt.% > PVA of 10 wt.% > DAY-zeolite of 10 wt.% > fly ash of 5 wt.% > DAY-zeolite of 5 wt.% > no additives. All this information is useful not only to the improvement of a pyrolysis system but also to the better utilization of liquid oil products.
Journal of Analytical and Applied Pyrolysis.
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ABSTRACT: The thermal degradation kinetics of polybutadiene rubber (BR) was investigated by dynamic thermogravimetry, in a nitrogen atmosphere, over the temperature range 177–577 °C and at constant nominal heating rates of 3, 5 and 7 °C/min, respectively. Two distinct mass change stages in the thermogravimetric analysis (TGA) curves indicated that the degradation of BR may be attributed to two reactions. The corresponding activation energies, frequency factors and reaction orders of the two reactions were determined. A simplified two-reaction model based on the TGA curves was also proposed for engineering purposes. Satisfactory agreements between the proposed model and the experimental results were obtained. The results of this study are useful for the utilization of scrap BR as an alternative energy resource.
Polymer Degradation and Stability.
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ABSTRACT: The pyrolytic reaction of chlorinated plastics such as poly(vinyl chloride) (PVC) releases hydrogen chloride (HCl). The HCl released from the pyrolysis, in turn, may affect the mechanisms of the pyrolytic reactions. In this study, the pyrolysis of high-density polyethylene (HDPE), being the principal component of plastics in the municipal solid waste (MSW), was carried out in the thermal gravimetric analysis (TGA) reaction system containing HCl gas. The results indicated that HCl inhibited the pyrolytic reaction of HDPE. The activation energies, pre-exponential factors, and reaction orders of the reactions corresponding to the various concentrations of HCl (CHCl) were obtained in the range of the experimental conditions. The results of this study are useful for the utilization of HDPE as an energy resource and for determining the thermal degradation rate of HDPE in an incinerator.
Journal of Hazardous Materials.
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ABSTRACT: Waste newspaper, one of the principal waste papers in Taiwan, was pyrolyzed with a thermogravimetric analysis (TGA) reaction system. The pyrolysis experiments were carried out in nitrogen environment at a constant heating rate of 5 K min−1. The pyrolysis products and the residues were collected and analyzed by gas chromatography and elemental analyzer, respectively. The major products investigated included non-hydrocarbons (H2, CO, CO2, and H2O) and hydrocarbons (C1–3, C4, C5, C6, 1-ring, C10–12, levoglucosan, C13–15, and C16–18). The cumulated masses and the instantaneous concentrations of pyrolysis products were obtained under the experimental conditions. The estimation of the mass of tar, yielded at various pyrolysis temperatures, was also made. The results of this study might be useful for the design of pyrolysis process as well as for determining the pyrolysis mechanisms of the newspaper.
Journal of Analytical and Applied Pyrolysis.
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ABSTRACT: Glycolysis of flexible polyurethane (PU) was investigated to provide useful data for the recycling of waste cars. The glycolysis experiments were performed under atmospheric pressure and isothermal condition (220 C). Diethylene glycol (DEG) and potas-sium acetate (KAc) were used as solvent and catalyst, respectively. The properties of glycolysis products were determined by ana-lyzing the hydroxyl value, weight average molecular weight (M w), viscosity, and the conversion (X) of the –NCOO– functional group in PU. The results indicate that the adequate concentrations of DEG and KAc are about 150 and 1% of the mass of the PU and an adequate reaction time is 90 min. Purification experiments on the glycolysis products were carried out in a stirred flask with a shell and tube condenser. The distilled materials were collected at the gas-phase temperature ranges of < 245, 245–260, 260–275, 275–290, and >290 C. The polyol-containing products are mostly in the temperature range of 245–260 C. The recovery of polyol-containing products can be achieved by the distillation of glycolysis products.
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ABSTRACT: The pyrolysis kinetics of a rubber mixture was investigated by a dynamic thermogravimetry reaction system at heating rates of 3, 5 and 7 K/min, in a nitrogen atmosphere, over the temperature range of 400 to 950 K. The results indicated that the pyrolytic reaction rates of rubber mixture can be represented by the summation of the corresponding reaction rates of the rubber components, based on their mass fractions. Satisfactory agreements between the proposed reaction model and the experimental results could be obtained. The results of this study are useful for the utilization of scrap rubber mixtures as an energy resource.
Journal of Hazardous Materials.
