• Journal of the Korean Ceramic Society
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• v.20 no.2
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• pp.166-172
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• 1983

In this study the sillicon-alloyed isotropic pyrolytic carbon was deposited in the tumbling bed from the pyrolysis of propane and silicon tetrachloride and investigated whether the silicon-alloyed isotropic pyrolytic carbon deposited in this study was usable as bionaterial or not. The silicon-allyed isotropic pyrolytic carbon was varied by controlling the process variables such as propane con-concentration and the argon flow rate flowing in to the silicon tetrachloride bubbler at a fixed reaction bed tempera-ture of 120$0^{\circ}C$ a rotation of reaction tube of 40 rpm a bed particle weight of 7.5 g and a total flow rate of 21/min; the propane concentration was varied from 10 to 70 and the argon flow rate flowing into the silicon tetrachloride bubble from 0 to 1000 cc/min. The results show that the silicon-alloyed isotropic pyrolytic carbon was obtained at all conditions investigated, . And then the alloyed silicon content is rangion from 7 to 14.5 wt%. The density and deposition rate of deposited silicon-alloyed isotropic carbon increased axxording to silicon content and propane concentration. And the apparent crystal-size(Lc) of pyrolytic carbon is not changed with silicon content. The density and apparant crystallite size are respec-tively in the range of 1.94 to 2.06 and 20 to 25$\AA$ It is shown that the silicon-alloyed isotropic pyrolytic carbon ob-tained in this experiment is usable as biomaterial.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.510-515
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• 2011

The pyrolytic reaction of 1,1-dichloroethylene($CH_2CCl_2$) has been conducted to investigate thermal decomposition of chlorocarbon and product formation pathways under hydrogen reaction environment. The reactions were studied in a isothermal tubular flow reactor at 1 atm total pressure in the temperature range $650{\sim}900^{\circ}C$ with reaction times of 0.3~2.0 sec. A constant feed molar ratio $CH_2CCl_2:H_2$ of 4:96 was maintained through the whole experiments. Complete decay(99%) of the parent reagent, $CH_2CCl_2$ was observed at temperature near $825^{\circ}C$ with 1 sec. reaction time. The important decay of $CH_2CCl_2$ under hydrogen reaction environment resulted from H atom cyclic chain reaction by abstraction and addition displacement. The highest concentration (28%) of $CH_2CHCl$ as the primary product was observed at temperature $700^{\circ}C$, where up to 46% decay of $CH_2CCl_2$ was occurred. The secondary product, $C_2H_4$ as main product was detected at temperature above $775^{\circ}C$. The one less chlorinated ethylene than parent increase with temperature rise subsequently. The HCl and dechlorinated hydrocarbons such as $C_2H_4$, $C_2H_6$, $CH_4$ and $C_2H_2$ were the main products observed at above $825^{\circ}C$. The important decay of $CH_2CCl_2$ resulted from H atom cyclic chain reaction by abstraction and addition displacement. The important pyrolytic reaction pathways to describe the features of reagent decay and intermediate product distributions, based upon thermochemical and kinetic principles, were suggested.

• Clean Technology
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• v.15 no.3
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• pp.186-193
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• 2009

The characteristics of product materials obtained from thermal degradation of low-qualify pyrolytic oil were investigated in this study. The reactants were produced by pyrolysis of mixed plastic waste with film type in a commercial rotary kiln reaction system. The properties of reactants were measured by elemental analysis, calorimetry analysis and SIMDIST analyst. The result of degradation experiments with different reaction temperature programs was discussed through product yields, cumulative yields and production rates of oil products. The multi-step reaction temperature program resulted in higher yields of product oils and lower yields of residues than one-step reaction temperature program. The product characteristics such as production yield and the rate of oil products etc. were influenced by reaction temperature program in the continuous thermal degradation.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.86-94
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• 2011

Pyrolytic lignin was obtained from biooil produced with yellow poplar wood. Fast pyrolysis was performed under various temperature ranges and residence times using fluidized bed type reactor. Several analytical methods were adopted to characterize the structure of pyrolytic lignin as well as the effect of pyrolysis temperature and residence time on the modification of the lignin. The yield of pyrolytic lignin increased as increasing pyrolysis temperature and decreasing residence time of pyrolysis products. The molecular weight of pyrolytic lignin determined by gel permeation chromatography (GPC) was approximately 1,200 mol/g, which was approximately a tenth of milled wood lignin (MWL) purified from the same woody biomass. Based on analytical data, demethoxylation and side chain cleavage reaction were dominantly occurred during fast pyrolysis.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.638-643
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• 2006

Pyrolytic reaction study of dichloromethane ($CH_{2}Cl_{2}$) in excess hydrogen was performed to investigate pyrolytic reaction pathways at a pressure of 1 atm with residence times of 0.3~2.0 sec in the temperature range of $525{\sim}900^{\circ}C$. A constant feed molar ratio $CH_{2}Cl_{2}$:$H_{2}$ of 4:96 was maintained through the experiment. Reagent loss and product formation were monitored by using an on-line gas chromatograph, where batch samples were analyzed by GC/MS. Complete destruction(99%) of the parent reagent was observed at temperature near $780^{\circ}C$ with residence time over 1 sec. Major products observed were $CH_{3}Cl$, $CH_{4}$, $C_{2}H_{4}$, $C_{2}H_{6}$, and HCl. Minor products included $CHClCCl_{2}$, CHClCHCl, $CH_{2}CHCl$, and $C_{2}H_{2}$. The pyrolytic reaction pathways to describe the important features of intermediate product distributions and reagent loss, based upon thermodynamic and kinetic principles, were suggested. The results of this work provided a better understanding of pyrolytic decomposition processes which occur during the pyrolysis of $CH_{2}Cl_{2}$ and similar chlorinated methanes.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.540-544
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• 2008

Pyrolytic characteristics of mixed plastics containing 22 wt.% HDPE, 17 wt.% LDPE, 27 wt.% PP, 12 wt.% PS, 16 wt.% ABS, 6 wt.% PVC have been studied in the batch-type microreactor of stainless steel. Thermal degradation experiments were performed at temperature of $410{\sim}450^{\circ}C$. The yield of each pyrolytic products were obtained by the weight measurement and molecular weight distribution of pyrolytic liquid products determined by the GC-SIMDIS method. It was shown that the yield and molecular weight of pyrolytic liquid product were decreased with the increase of reaction temperature and time. It was know that 20wt% of PVC composing of the mixed plastics was converted to the gas products of chloride during the pyrolysis process. The chain-end scission rate parameter was determined to be 50.2 kcal/mole of mixed plastics by the Arrhenius plot.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.11
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• pp.1046-1053
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• 2010

The objective of this study was to investigate the pyrolytic reaction characteristics of a mixed fuel of municipal solid wastes and low-grade anthracite. The reaction variables are pyrolysis condition of mixing ratio, reaction temperature, temperature increase rate. As a result, the optimum mixing ratio was 20 wt.% low-grade anthracite in MSW, which maintains for the low heating value over 3,500 kcal/kg on pyrolysis. The most high reaction velocity constant was shown at $700^{\circ}C$. Also, under the all experimental condition, the reaction velocity constant increased linearly as temperature rate increase, but pyrolysis has to be considered electric power cost and yield of char at lower temperature rate.

• Clean Technology
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• v.16 no.3
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• pp.198-205
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• 2010

Two sets of thermal reaction experiment for chlorinated hydrocarbons were performed using an isothermal tubular-flow reactor in order to investigate thermal decomposition, including product distribution of chlorinated hydrocarbons. The effects of $H_2$ or Ar as the reaction atmosphere on the thermal decomposition and product distribution for dichloromethane($CH_2Cl_2$) was examined. The experimental results showed that higher conversion of $CH_2Cl_2$ was obtained under $H_2$ atmosphere than under Ar atmosphere. This phenomenon indicates that reactive-gas $H_2$ reaction atmosphere was found to accelerate $CH_2Cl_2$ decomposition. The $H_2$ plays a key role in acceleration of $CH_2Cl_2$ decomposition and formation of dechlorinated light hydrocarbons, while reducing PAH and soot formation through hydrodechlorination process. It was also observed that $CH_3Cl,\;CH_4,\;C_2H_6,\;C_2H_4$ and HCl in $CH_2Cl_2/H_2$ reaction system were the major products with some minor products including chloroethylenes. The $CH_2Cl_2$/Ar reaction system gives poor carbon material balance above reaction temperature of $750^{\circ}C$. Chloroethylenes and soot were found to be the major products and small amounts of $CH_3Cl$ and $C_2H_2$ were formed above $750^{\circ}C$ in $CH_2Cl_2$/Ar. The thermal decomposition reactions of chloroform($CHCl_3$) with argon reaction atmosphere in the absence or the presence of $CH_4$ were carried out using the same tubular flow reactor. The slower $CH_3Cl$ decay occurred when $CH_4$ was added to $CH_3Cl$/Ar reaction system. This is because :$CCl_2$ diradicals that had been produced from $CHCl_3$ unimolecular dissociation reacted with $CH_4$. It appears that the added $CH_4$ worked as the :$CCl_2$ scavenger in the $CHCl_3$ decomposition process. The product distributions for $CHCl_3$ pyrolysis under argon bath gas were distinctly different for the two cases: one with $CH_4$ and the other without $CH_4$. The important pyrolytic reaction pathways to describe the important features of reagent decay and intermediate product distributions, based upon thermochemistry and kinetic principles, were proposed in this study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.914-917
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• 2002

Fabrication of micro carbon structures and patterns using laser-assisted chemical vapor deposition is studied. Argon ion laser and ethylene were used to grow micro carbon rod through pyrolytic decomposition of the reaction gas. The influence of reaction gas pressure and incident laser power on the diameter and growth rate of the micro carbon rod was experimentally investigated. The diameter of micro carbon rods increases linearly with respect to the laser power but is almost independent of the reaction gas pressure. Growth rate of the rod changes little with gas pressure when the laser power remains below 1W. When the carbon rod was grown at near threshold laser power, a very smooth surface is obtained on the rod. By continuously moving the focusing lens in the direction of growth, a micro carbon rod with a diameter of 28 ${\mu}{\textrm}{m}$ and aspect ratio of 100 was fabricated.

• Journal of the Korean Ceramic Society
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• v.44 no.3 s.298
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• pp.169-174
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• 2007

TRISO coated fuel particle is one of the most important materials for hydrogen production using HTGR (high temperature gas cooled reactors). It is composed of three isotropic layers: inner pyrolytic carbon (IPyC), silicon carbide (SiC), outer pyrolytic carbon (OPyC) layers. In this study, TRISO coated fuel particle layers were deposited through CVD process in a horizontal hot wall deposition system. Also the computational simulations of input gas velocity, temperature profile and pressure in the reaction chamber were conducted with varying process variable (i.e temperature and input gas ratios). As deposition temperature increased, microstructure, chemical composition and growth behavior changed and deposition rate increased. The simulation showed that the change of reactant states affected growth rate at each position of the susceptor. The experimental results showed a close correlation with the simulation results.