• Journal of the Korean Applied Science and Technology
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• v.23 no.4
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• pp.307-318
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• 2006

The pyrolysis of high density polyethylene(HDPE) and low density polyethylene(LDPE) was carried out at temperature between 425 and $500^{\circ}C$ from 35 to 80 minutes. The liquid products formed during pyrolysis were classified into gasoline, kerosene, gas oil and wax according to the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. The conversion and yield of liquid products for HDPE pyrolysis increased continuously according to pyrolysis temperature and pyrolysis time. The influence of pyrolysis temperature was more severe than pyrolysis time for the conversion of HDPE. For example, the liquid products of HDPE pyrolysis at $450^{\circ}C$ for 65 minutes were ca. 30wt.% gas oil, 15wt.% wax, 14wt.% kerosene and 11wt.% gasoline. The increase of pyrolysis temperature up to $500^{\circ}C$ showed the increase of wax product and the decrease of kerosene. The conversion and yield of liquid products for LDPE pyrolysis continuously increased according to pyrolysis temperature and pyrolysis time, similar to HDPE pyrolysis. The liquid products of LDPE pyrolysis at $450^{\circ}C$ for 65 minutes were ca. 27wt.% gas oil, 18wt.% wax, 16wt.% kerosene and 13wt.% gasoline.

• Korean Journal of Materials Research
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• v.15 no.8
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• pp.496-502
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• 2005

Green-light emitting $BaMgAl_{10}O_{19}:Mn^{2+}$ (BAM:Mn) phosphor particles were prepared by spray Pyrolysis. The effect of reactor temperature and flow rate of carrier gas in the spray Pyrolysis on the morphology, crystallinity and photoluminescence characteristics under vacuum ultraviolet were investigated. The morphology of the as-Prepared Particles obtained by spray Pyrolysis had spherical shape and non-aggregation characteristics regardless of the reactor temperature. The spherical shape of the as-prepared Particles obtained by spray pyrolysis at low temperature disappeared after Post-treatment. On the other hand the as-Prepared Particles obtained by spray Pyrolysis at $1600^{\circ}C$ maintained spherical shape and non-aggregation characteristics after post-treatment at $1400^{\circ}C$ for 3 h under reducing atmosphere. The BAM:Mn Phosphor Particles Prepared by spray Pyrolysis at different reactor temperatures had pure crystal structure and high photoluminescence intensities under vacuum ultraviolet after post-treatment. BAM:Mn phosphor particles prepared by spray Pyrolysis at low How rate of carrier gas had complete spherical shape and filed morphology and high photoluminescence intensity after post-treatment under reducing atmosphere.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.553-556
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• 2009

This research aims at the recovery of valuable resource and more efficient waste treatment through solving the problem of pyrolysis technique. At first, in order to raise the economical efficiency, the low temperature pyrolysis experiment was carried out at the temperature of $450^{\circ}C$, which is lower than the common pyrolysis temperature area ($500{\sim}1000^{\circ}C$). We could lower the reaction temperature and reduce the reaction time by using catalyst. Also we used indirect heat for the purpose of maintaining favorable anoxic condition. As a result, we could raise the recovery rate of the valuable copper and synthetic fuel oil. Furthermore, the by-products and flue gas could be treated more effectively as well. The flue gas passed through two stage neutralization tank, so that dioxin hardly occurs and other environment items are controlled fairly well to the environmental standard. Throughout this study, we produced the low temperature pyrolysis equipment (GTPK-001) as mentioned above, and we found out that the technique can be commercialized economically as well as environmentally friendly.

• New & Renewable Energy
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• v.18 no.4
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• pp.12-21
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• 2022

The pyrolysis characteristics of high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP) were analyzed numerically using a 1D plug flow reactor (PFR) model. A lumped kinetic model was selected to simplify the pyrolysis products as wax, oil, and gas. The simulation was performed in the 400-600℃ range, and the plastic pyrolysis and product generation characteristics with respect to time were compared at various temperatures. It was found that plastic pyrolysis accelerates rapidly as the temperature rises. The amounts of the pyrolysis products wax and oil increase and then decrease with time, whereas the amount of gas produced increases continuously. In LDPE pyrolysis, the pyrolysis time was longer than that observed for other plastics at a specified temperature, and the amount of wax generated was the greatest. The maximum mass fraction of oil was obtained in the order of HDPE, PP, and LDPE at a specified temperature, and it decreased with temperature. Although the 1D model adopted in this study has a limitation in that it does not include material transport and heat transfer phenomena, the qualitative results presented herein could provide base data regarding various types of plastic pyrolysis to predict the product characteristics. These results can in turn be used when designing pyrolysis reactors.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.122-127
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• 1963

Pyrolysis fo polyethylene and polypropylene has been studied in order to clarify the mechanism of chain scission and effect of oxygen on degradation. Rate of weight decrease was measured under nitrogen and air atmosphere at constant temperature for the samples of high density polyethylene, low density polyethylene and isotactic polypropylene, and then gaseous hydrocarbons produced from pyrolysis were analysed by gas chromatography. Although there is little substantial difference between composition of hydrocarbon gases from pyrolysis of high density polyethylene and low density polyethylene except some difference in quantity of total gas produced, gas composition from polypropylene pyrolysis differs from that of polyethylene pyrolysis. Gases from pyrolysis under air contain much more unsaturated hydrocarbons than those from pyrolysis under inert gas.

• Journal of environmental and Sanitary engineering
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• v.22 no.1 s.63
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• pp.1-16
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• 2007

The incineration process has commonly used for wastes amount reduction and thermal treatments of pollutants as the technologies accumulated. However, the process is getting negative public images owing to matter of hazardous pollutants emission. Specially dioxins became a main issue and is mostly emitted from municipal solid wastes incineration. In this reason, pyrolysis/gasfication/melting process is presented as a alternative of incineration process. The pyrolysis/gasfication/melting process, a novel technology, is middle of verification of commercial plant and development of technologies in Korea. But the survey about the pollutant emission from the process, and background data in these facilities is necessary. So in this survey, it Is investigated that the behavior of dioxins in three pyrolysis/gasfication/melting plant (S, T, P) of pilot scale. In case of S plant, concentration of dioxins shows high at latter part of cogenerated boiler and stack which are operate on low temperature conditions than a latter parts of pyrolysis and melting furnace which are operate on high temperature condition. Concentration of gas phage dioxins had increased after combusted gas passed cogenerated boiler and this is attributed to react of precursor materials such as chlorobenzene and chlorophenol. Concentration of dioxins in T plant showed lower levels at latter part of cooling equipment which are operate with water spray type on low temperature conditions than a latter parts of gasfied melting furnace which are operate on high temperature condition. Removal efficiency of dioxins at gas treatment equipment was 78.8 %. Concentration of dioxins in P plant was low at latter part of SDA/BF which is operate at low temperature conditions than a latter parts of pyrolysis gasfied chamber which are operate at high temperature condition. Removal efficiency of dioxins of SDA/BF was 85.9 % and therefore, it showed high efficiency at those of stoker type incineration facility. However, concentration of dioxins which emitted at high temperature condition were low in three facilities and satisfied present standard emission level of dioxins. To consider the distribution ratio of dioxins, Particulate phase dioxins at S and P plants showed similar ratio with which shows in current stoker type for middle scale domestic waste incineration facility. It is necessary to continuos monitoring the ratio of distribution of dioxins in T plant in because ratio of gas phage dioxins showed high.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.223-226
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• 2009

In this study, we investigated the recovery of copper and synthetic fuel from the waste wire by low temperature pyrolysis which can overcome problems of the recent incineration methods. Through thermal decomposition process of waste wire, we achieved the big advantage of getting usable resources as the forms of copper and fuel with a very high value. The TG/DTA and small-scale reaction experiments were carried out to determine an optimum temperature for waste wire pyrolysis. And the pyrolysis was done at 350, 450, and $550^{\circ}C$, respectively, and heating rate of the TG/DTA was $5^{\circ}C/min$ untill $700^{\circ}C$. The result shows that the optimum temperature range for dehydrochlorination of PVC was $280{\sim}350^{\circ}C$, as a lower temperature range than $400{\sim}550^{\circ}C$ of PE and PP. Practically over 95% of copper metal and synthetic fuel, which has the 8027 kcal/kg as a calorific value, were recovered from the waste wire samples.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.1-5
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• 2021

Field-effect transistors based on solution-processed metal oxide semiconductors has attracted huge attention due to their intrinsic characteristics of optical and electrical characteristics with benefits of simple and low-cost process. Especially, spray-pyrolysis has shown excellent device performance which compatible to vacuum-processed Field-effect transistors. However, the high annealing temperature for crystallization of MOS and narrow range of precursors has impeded the progress of the technology. Here, we demonstrated the nc-ZnO/ZnO films performed by spray-pyrolysis with incorporating ZnO nanoparticles into typical ZnO precursor. The films exhibit preserving morphological properties of poly-crystalline ZnO and enhanced electrical characteristics with potential for low-temperature processability. The influence of nanoparticles within the film was also researched for realizing ZnO films providing good quality of performance.

• Journal of Energy Engineering
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• v.2 no.2
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• pp.208-214
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• 1993

Pyrolysis of bituminous coal has been carried out in a two-stage fixed bed reactor to produce high heating value gas(7000 kcal/N㎥) for industrial or town gas usage. The effects of coke catalyst, pyrolysis temperature (468∼565$^{\circ}C$), and catalytic cracking temperature (700∼850$^{\circ}C$) on the product gas properties from pyrolysis of bituminous coal have been determined. From pyrolysis of Dong Jin coal with coke, the carbon deposition on catalyst is found to be less than 5% of product tar and approximately 15% of total energy iii the parent coal can be recovered as high heating value gas. Oil composition in the product tar from the two-stage pyrolysis is higher than that from low-temperature pyrolysis. The tar produced from pyrolysis below 516$^{\circ}C$ can be easily catalytically cracked but, the tar produced above 565$^{\circ}C$ cannot be cracked easily with catalyst. From the product gas analysis, the catalytic cracking temperature should be maintained below 800$^{\circ}C$ since cracking speed of ethylene increases remarkably with the cracking temperature above 800$^{\circ}C$.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.391-399
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• 2023

Recently, low-temperature pyrolysis technology has been studied as a recycling method for waste plastic. Low-temperature pyrolysis technology for waste plastic produces pyrolysis oil that can be used as an energy resource, but solid residue remains. Waste plastic pyrolysis residues are mostly landfilled due to their limited use. In this study, it is investigated that mixed waste plastic pyrolysis residues could be recycled into activated carbon. It was confirmed that the fixed carbon content of the residue was 33.69 % from proximate Analysis. Chemical activation was used to manufacture activated carbon. KOH was used as an activator. To investigate the effect of the mixing ratio of KOH and residue, samples were mixed at ratios of 0.5, 1.0, and 2.0. The mixed sample was chemically activated at an activation temperature of 800 ℃ for 1 hour. As a result of analyzing the characteristics of activated carbon through BET, it was confirmed that the specific surface area increased as the mixing ratio of KOH increased.