• Journal of the Korean Chemical Society
• /
• v.7 no.2
• /
• pp.106-114
• /
• 1963

The products from polymer pyrolysis at $450^{\circ}$ are cooled with ice, then liquid and gaseous portions are analysed by gas chromatography. Di-2-ethyl hexyl sebacate column, silicone oil column, silica gel column and tetraethyleneglycol dimethylether column, which was most effective for the separation of hydrocarbon gases, are used. Identification of isomers could be secured more effectively by gas chromatography than mass spectrometry. Elucidation of the mechanism for thermal decomposition of polymers could be done through the identification of pyrolysis products. Although more extensive work is needed, some patterns of polymer pyrolysis are discussed.

• Applied Chemistry for Engineering
• /
• v.29 no.3
• /
• pp.350-355
• /
• 2018

In this study, the effect of biomass torrefaction on the thermal and catalytic pyrolysis of cork oak was investigated. The thermal and catalytic pyrolysis behavior of cork oak (CO) and torrefied CO (TCO) were evaluated by comparing their thermogravimetric (TG) analysis results and product distributions of bio-oils obtained from the fast pyrolysis using a fixed bed reactor. TG and differential TG (DTG) curves of CO and TCO revealed that the elimination amount of hemicellulose in CO increased by applying the higher torrefaction temperature and longer torrefaction time. CO torrefaction also decreased the oil yield but increased that of solid char during the pyrolysis because the contents of cellulose and lignin in CO increased due to the elimination of hemicellulose during torrefaction. Selectivities of the levoglucosan and phenolics in TCO pyrolysis oil were higher than those in CO pyrolysis oil. The content of aromatic hydrocarbons in bio-oil increased by applying the catalytic pyrolysis of CO and TCO over HZSM-5 ($SiO_2/Al_2O_3=30$). Compared to CO, TCO showed the higher efficiency on the formation of aromatic hydrocarbons via the catalytic pyrolysis over HZSM-5 and the efficiency was maximized by applying the higher torrefaction and catalytic pyrolysis reaction temperatures of 280 and $600^{\circ}C$, respectively.

• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.12
• /
• pp.1371-1380
• /
• 2007

Study on the instability of waste plastic's thermal pyrolysis oil was carried out for the purpose of improving its quality. The reaction of pyrolysis oil with ozone changed double bonds into aldehydes and ketone, estimated that HDPE pyrolysis oil contained $\sim45$ wt% 1-alkene type olefins, and PP pyrolysis oil did $\sim73$ wt% olefins, which consisted of $\sim47$ wt% secondary and $\sim20$ wt% primary alkenes. The dark brown color and odor of pyrolysis oil were improved by eliminating double bonds, indicated that they were directly related to unsaturated hydrocarbons. Container test showed that metal can affected oil quality worse than the brown glass bottle. Antioxidant added into pyrolysis oil was consumed up to 90% within $2\sim3$ days and the wt. composition of unsaturated hydrocarbons in pyrolysis oil was not changed within 50 days, inferring that instability of pyrolysis oil due to unsaturated bonds can be stabilized by antioxidants. Adsorption test on silica gel, activated carbon and alumina to remove precipitates in oil produced a good result, but not enough to remove moisture. However, cheap anhydrous sodium carbonate showed the best removal efficiency of moisture as well as precipitates in oil. Therefore the pyrolysis oil quality improvement was accomplished by applying anhydrous $Na_2CO_3$ into the production plant.

• Korean Journal of Materials Research
• /
• v.19 no.11
• /
• pp.581-587
• /
• 2009

Fe powders with elongated and aggregated structure as heat pellet material for thermal battery applications were prepared by spray pyrolysis under various preparation conditions. The precursor powders with spherical shapes and hollow morphologies turned into Fe powders after reduction at a temperature of 615$^{\circ}C$ under 20% $H_2$/Ar gas. The powders had pure Fe crystal structures irrespective of the preparation conditions of the precursor powders in the spray pyrolysis. The morphologies and mean sizes of the Fe powders are affected by the preparation conditions of the precursor powders in the spray pyrolysis. Therefore, the ignition sensitivities and the burn rates of the heat pellets formed from the Fe powders prepared by spray pyrolysis are affected by the preparations of the precursor powders. The Fe powders prepared under the optimum preparation conditions have a BET surface area of 2.9 $m^2g^1$. The heat pellets prepared from the Fe powders with elongated and aggregated structure have a good ignition sensitivity of 1.1W and a high burn rate of 18 $cms^1$.

• Fire Science and Engineering
• /
• v.32 no.3
• /
• pp.1-7
• /
• 2018

This study the effect of pyrolysis products ABC dry chemical and of monoammonium phosphate on wood surface. When the pyrolysis product was removed from the wood surface, monoammonium phosphate was removed due to the high viscosity of the transparent pyrolysis product, but the ABC dry chemical was removed in a lump form. Thermal analysis showed that the pyrolysis characteristics of each sample were similar but the weight of pyrolysis residue was 55.9% for ABC dry chemical and 25.2% for monoammonium phosphate. The additives added to the ABC dry chemical also affect the weight of the pyrolysis residue and the fire protection effect of metaphosphoric acid.

• Journal of the Korean Society of Combustion
• /
• v.14 no.4
• /
• pp.33-40
• /
• 2009

Waste Thermal Pyrolysis Melting process was proposed and has been studied in order to prevent air pollution by dioxin and fly ash generated from combustion process for disposal of waste. In this study, applicability as the fuel of diffusion burner of synthesis gas formed from Waste Thermal Pyrolysis process was addressed. Results showed that there is no big difference in the flame shape between MNDF and SNDF, and lift off was detected in MIDF but flame is more stable in SIDF which contains hydrogen with high combustion velocity as flow rate in first nozzle is increased. And radiation heat flux in inverse diffusion flame of synthesis gas was found to be more by 1.5 times than that in inverse diffusion flame of methane because of higher mole fraction of $CO_2$ with high emissivity in product gas.

• Advanced Composite Materials
• /
• v.18 no.1
• /
• pp.61-75
• /
• 2009

The effect of porous matrix on thermal fatigue behavior of 3D-orthogonally woven SiC/SiC composite was evaluated in comparison with that having relatively dense matrix. The porous matrix yields open air passages through its thickness which can be utilized for transpiration cooling. On the other hand, the latter matrix is so dense that the air passages are sealed. A quantity of the matrix was varied by changing the number of repetition cycles of the polymer impregnation pyrolysis (PIP). Strength degradation of composites under thermal cycling conditions was evaluated by the $1200^{\circ}C$/RT thermal cycles with a combination of burner heating and air cooling for 200 cycles. It was found that the SiC/SiC composite with the porous matrix revealed little degradation in strength during the thermal cycles, while the other sample showed a 25% decrease in strength. Finally it was demonstrated that the porous structure in 3D-SiC/SiC composite improved the thermal fatigue durability.

• Journal of Energy Engineering
• /
• v.17 no.1
• /
• pp.8-14
• /
• 2008

The effects of calcium type catalysts addition on the thermal decomposition of low density polyethylene (LDPE) and ethylene vinyl acetate (EVA) resin have been studied in a thermal analyze. (TGA, DSC) and a small batch reactor. The calcium type catalysts tested were calcinated dolomite, lime, and calcinated oyster shell. As the results of TGA experiments, pyrolysis starting temperature for LDPE varied in the range of $330{\sim}360^{\circ}C$ according to heating rate, but EVA resin had the 1st pyrolysis temperature range of $300{\sim}400^{\circ}C$ and the 2nd pyrolysis temperature range of $425{\sim}525^{\circ}C$. The calcinated dolomite enhanced the pyrolysis rate in LDPE pyrolysis reaction, while the calcium type catalysts reduced the pyrolysis rate in EVA pyrolysis reaction. In the DSC experiments, addition of calcium type catalysts reduced the melting point, but did not affect to the heat of fusin. Calcinated dolomite reduced 20% of the heat of pyrolysis reaction. In the batch system experiments, the mixing of calcinated dolomite and lime enhanced the yield of fuel oil, but did not affect to the distribution of carbon numbers.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.126-129
• /
• 2007

The particle formation using pyrolysis has many advantages over other particle manufacturing techniques. The particles by pyrolysis have relatively uniform size and chemical composition. Also, we can easily produce high purity particles. Thus, we studied the formation of silicon particles by pyrolysis of 50% $SiH_4$ gas diluted in Ar gas. A pyrolysis furnace was used for the thermal decomposition of $SiH_4$ gas at $800^{\circ}C$ and atmospheric pressure. The aerosol flow from furnace is separated into two ways. The one is to the Scanning Mobility Particle Sizer (SMPS) for particle size distribution measurement and the other is to the particle deposition system. The produced silicon particles are deposited on the wafer in the deposition chamber. SEM measurement was used to compare the particle size distribution results from the SMPS. Depending on the experimental conditions, particles of high concentration in the $30\sim80$ nm size range were generated.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.3 no.2
• /
• pp.37-47
• /
• 1999

This paper describes the thermal analysis which can calculate the ablation depth and temperature distribution of the rocket nozzle liner allowing geometry change caused by the ablation of nozzle liner. In this analysis, Zvyagin's model is used for surface ablation and Yaroslavtseva's model for in-depth pyrolysis. A deforming finite-element grid is used to account for external-boundary movement due to the erosion of thermal liner. The accuracy of the present numerical method is evaluated with a rocket nozzle liner and the numerical solutions are favorably agreed with experimental data. The temporal variations of temperature and ablation depth at the thermal liner of another rocket nozzle are numerically simulated and the results are discussed. Special emphasis is given to the effects of kinetic constants for carbon-carbon and carbon-phenolic composites on the ablation depth of thermal liner.