• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.432-437
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• 1999

Pyrolysis of polyethylene was carried out in the stainless steel reactor of internal volume of $10cm^3$. Pyrolysis reactions were performed at temperature $390{\sim}450^{\circ}C$ and the pyrolysis products were collected separately as reaction products and gas products. The molecular weight distributions(MWDs) of each product were determined by HPLC-GPC and GC analysis. Distribution balance equation for MWDs of random and specific products were proposed to account for initiation-termination and propagation-depropagation, such as hydrogen abstraction, chain cleavage, coupling of polymer and radical. A separate chain-end scission process produces low molecular weight noncondensable gases(C1 through C5) of average molecular weight 38. Activation energies of the random-chain scission and chain-end scission rate parameters, respectively, were determined to be 35, 17 kcal/mole.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.104-108
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• 1993

Thin films of MgO-doped and CaO-doped iron oxide were prepared y spray pyrolysis. The films were characterized b X-ray diffraction, scanning electron microscopy and voltammetric techniques. The photoelectrochemical behavior of thin film electrodes depended greatly on the doping level, sintering temperature, substrate temperature and added photosensitizing compounds in solution, showed p-type photoelectrochemical behavior, while the CaO-doped iron oxide thin films prepared at low temperature showed n-type photoelectrochemical behavior. This characteristic change was interpreted in terms of the surface structure change of the thin films and doping effect of metal oxide.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.867-873
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• 2007

Thermal degradation characteristics of polypropylene and polystyrene have been studied in the thermogravimetric(TG) reactor and batch-type microreactor. The dynamic thermogravimetric curve of TG provided a valuable information about pyrolysis temperature. It was found that PS was thermally degraded at lower temperature of $30{\sim}50^{\circ}C$ than PP. It was found that the yield and molecular weight of liquid product in the microreactor were decreased with the increase of reaction temperature and time in the case of PP. The production of styrene monomer was significantly increased by the promotion of depolymerization with the increase of temperature and time. The chain-end scission rate parameters were determined to be 50.0 kcal/mole of PP, 45.2 kcal/mole of PS by the Arrhenius plot.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.143-144
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• 2000

The aerosol pyrolysis technique was introduced to prepare the spherical phosphors for enhancing low-voltage phosphor efficiency. The density, the shape, and the crystallinity of phosphors were controlled by thermal decomposition temperature and phosphor annealing condition. The particle size was adjusted by the precursor concentration and reactor pressure. It was fond that the efficiency of phosphors synthesized in this work was superior to the commercial products at the low-voltage excitation by 1.5 times and the screen efficiency was also higher than that of any value reported in literature.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1013-1019
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• 2007

Electronic wastes have increased tremendously. However, any reliable treatment methodologies have rarely been established. Electronic wastes have posed serious disposal problem due to their physico-chemical stability. This paper investigated the application possibility of pyrolysis for the purpose of recycling the p-CCL(phenol based Copper Clad Laminate). Thermogravimetric analysis(TGA) was used to investigate the thermal decomposition pattern of p-CCL. We elucidated the characteristics of pyrolysis by-products at operating temperatures of 280, 350 and $600^{\circ}C$. GC/MS and FT-IR were used to characterize the liquid by-products along with general characterization methods such as Ultimate Analysis, Proximate Analysis and Heating Value, whereas general characterization methods were only introduced for the solid by-products. At a heating rate of $5^{\circ}C$/min, TGA curves exhibited three decomposition stages: (1) low-temperature decomposition region$(<280^{\circ}C)$, (2) medium temperature region$(280\sim350^{\circ}C)$ and (3) high-temperature region$(>350^{\circ}C)$. The major compounds of liquid by-products at low- and medium-temperatures were accounted for by water and phenol, whereas branched phenols and furans were major compounds at high-temperatures. As the temperature increases, volatile quantities decreased but the fixed carbon increased. High heating values of solid by-products($7,400\sim7,600$ kcal/kg) would suggest that the solid by-products could be applicable as fuel. In addition, high fixed carbon but low ash content of the solid by-products offered an implication that they are capable of being upgradable for adsorbent after applying appropriate activating process.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.443-451
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• 2020

In this study, the physico-chemical properties and pyrolysis kinetics of livestock mature solid fuel were investigated to know its feasibility as a fuel. Ultimate and proximate analysis results showed that livestock mature solid fuel has high contents of volatile matter (64.94%), carbon (44.35%), and hydrogen (5.54%). The low heating value of livestock mature solid fuel (3880 kcal/kg) was also higher than the standard requirement of solid fuel (3000 kcal/kg). Thermogravimetic analysis results indicated that livestock mature solid fuel has three decomposition temperature regions. The first temperature zone (130~330 ℃) was consisted with the vaporization of extracts and the decomposition of hemicellulose and cellulose. The second (330~480 ℃) and third (550~800 ℃) temperature regions were derived from the decomposition of lignin and additional decomposition of carbonaceous materials, respectively. The activation energy derived from model free kinetic analysis results including Friedman, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS) methods for the pyrolysis of livestock mature solid fuel was in the range of 173.98 to 525.79 kJ/mol with a conversion rate of 0.1 to 0.9. In particular, the activation energy increased largely at the higher conversion than 0.6. The kinetic analysis using a curve-fitting method suggested that livestock mature solid fuel was decomposed via a multi-step reaction which can be divided into five decomposition steps.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.7
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• pp.873-880
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• 2020

After pre-treatment of oyster shells according to particle size (0 ~ 1, 1 ~ 2, 2 ~ 5 mm) and pyrolysis temperature (400(P400), 500(P500), 600(P600), 800(P800)℃), changes in the properties of sediments mixed with pre-treated oyster shells were investigated. The primary component of the oyster shell was changed from CaCO3 to CaO at temperatures above 700℃. The Ca2+ concentration in P800 was 790 mg/L, which was 2 ~ 3 times higher than those in the control and other experimental samples. Ca2+ elution significantly increased at the pyrolysis temperature over than 600℃. In oyster shells pyrolyzed over 600℃, the pH of the pore water increased by 0.1 ~ 0.5, due the hydrolysis of CaO formed by the pyrolysis of CaCO3. The PO4-P of the overlying and pore water in P600 and P800 were 0.1 ~ 0.2 mg/L lower than those of the control. The increased pH and elution of Ca2+ from oyster shells should suppress the upwelling of PO4-P from the sediment. Based on the above results, it was confirmed that the pyrolysis temperature of oyster shells influenced NH3-N and PO4-P concentrations in the sediment; however, the particle size of oyster shells had little effect. The results of this study can be used as a foundation for research on the use of pyrolyzed oyster shells to improve low-contamination coastal benthic environments.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.31-37
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• 1994

Aluminum films were deposited by the pyrolysis of triisobutylaluminum(TIBA) in a cold wall LPCVD system for the metallization of high level IC. the selectivity on Si/SiO2 substrate and the contact resistance on submicron contacts were investigated. The carbon free aluminum film could be obtained when the aluminum film was deposited at low substrate temperature. Contact resistances of CVD Al/n+ Si contacts whose contact size was 0.5 .mu.m werre as low as 20~40.OMEGA./ea, which is 30~50% of contact resistance obtained by sputtering technique.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.3
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• pp.294-302
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• 1998

Ignition characteristics of a vertical solid fuel plate with block have been investigated experimentally. For low radiant heat flux, ignition does not occur in a vertical solid fuel plate without block. In the case with the block on a vertical fuel plate, however, ignition can occur by increasing the residence time and the time to absorb the incident radiation flux by fuel vapor in gas phase. The ignition occurs below block and the point varies according to the block location and the block height. As the block height increases, the block locates at higher position, and the hot wall temperature increases, the ignition delay time decreases. Also as the initial temperature of fuel plate rises, the ignition delay time of the solid fuel plate decreases. The temperature distribution of solid fuel plate with block is nearly proportional to the radiant heat flux distribution. Therefore, the effect temperature by natural convection heat transfer is of the same order as that of inhibition of temperature increase by pyrolysis.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.616-620
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• 2005

The morphology and photoluminescence characteristics of green light emitting hexaaluminate phosphor particles prepared by high temperature spray pyrolysis from spray solution with and without ammonium dihydrogen phosphate flux were investigated. The particles prepared from spray solution without flux material had hollow morphology at preparation temperatures between $900^{\circ}C$ and $1,650^{\circ}C$. Ammonium dihydrogen phosphate flux added into spray solution enabled the formation of particles with spherical shape and filled morphology at preparation temperatures between $900^{\circ}C$ and $1,650^{\circ}C$. The hexaaluminate phosphor particles with magnetoplumbite structure were directly prepared by spray pyrolysis from spray solution with ammonium dihydrogen phosphate flux above $1,600^{\circ}C$. Ammonium dihydrogen phosphate flux was effective in improving the photoluminescence intensity of the phosphor particles at low preparation temperatures. The phosphor particles prepared from spray solution with and without flux material by spray pyrolysis under reducing atmosphere at $1,650^{\circ}C$ had comparable photoluminescence intensities with that of the phosphor particles optimized by post-treatment.