• Journal of the Korean Society of Tobacco Science
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• v.17 no.2
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• pp.160-169
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• 1995

A mathematical model for the pyrolysis processes during unforced smoldering of cigarette was proposed in this study by analyzing the physical model of the smoldering cigarette (including the establishment of burning front between burning zone and pyrolysis zone, and analyzing the involvement of main factors such as pyrolysis of virgin tobacco, evaporation of water, and internal heat transport in the processes). Thermal conduction of cigarette paper and convective and radiative heat transfer at the outer surface were also considered via the thermal resistance law for the competitive heat transfer mechanisms. The governing partial differential equations were solved using an integral method. Model predictions of smoldering speed, or linear burn rate, as well as temperature and density profiles in the pyrolysis zone for different kinds of cigarettes were found to be close to the experimental data in the literature (Muramatsu, 1981). The model provides a relatively fast and efficient way to simulate the pyrolysis processes and offers a practical tool for exploring important parameters for a smoldering cigarette, such as blended tobacco composition, properties of cigarette paper, and heat flux from the burning zone to the pyrolysis zone.

• Journal of Korea Society of Waste Management
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• v.34 no.7
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• pp.685-696
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• 2017

This study focuses on computational particle fluid dynamics (CPFD) modeling for the fast pyrolysis of biomass in a conical spouted bed reactor. The CPFD simulation was conducted to understand the hydrodynamics, heat transfer, and biomass fast pyrolysis reaction of the conical spouted bed reactor and the multiphase-particle in cell (MP-PIC) model was used to investigate the fast pyrolysis of biomass in a conical spouted bed reactor. A two-stage semi-global kinetics model was applied to model the fast pyrolysis reaction of biomass and the commercial code (Barracuda) was used in simulations. The temperature of solid particles in a conical spouted bed reactor showed a uniform temperature distribution along the reactor height. The yield of fast pyrolysis products from the simulation was compared with the experimental data; the yield of fast pyrolysis products was 74.1wt.% tar, 17.4wt.% gas, and 8.5wt.% char. The comparison of experimental measurements and model predictions shows the model's accuracy. The CPFD simulation results had great potential to aid the future design and optimization of the fast pyrolysis process for biomass.

• 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.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.77-84
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• 2022

The experimental work has been carried out for the study of pyrolysis of oil samples used in industrial and utility boilers in Korea. For five oil samples, the characteristics of pyrolysis have been investigated with a thermogravimetric analyzer (TGA), and their kinetic parameters were obtained and compared each other. The rate order of pyrolysis rate for five oils were as follows: by-product fuel oil, pyrolysis oil, diesel, a heavy oil and refined oil. The pyrolysis of refined oil has been successfully described by the three step, first order reaction model while the single step reaction model has been used for other oils. For the reaction temperature over 550 K, the reactivity of refined oil was very poor compared with other oils.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.35-41
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• 2001

Lignin model compounds I-lV were pyrolyzed at 315$^{\circ}C$. The mixture compounds pyrolized were analyzed by GC-MS spectrometry. The results were summarized as follows : 1. From the pyrolysis of lignin model compound I and II, 0.45mo1 of guaiacol, 0.5mol of dimethoxyphenol(DMP), and 0.12 and 0.23mo1 of dimethoxyacetonphenone(DMAP) were produced respectively. 2. In the pyrolysis of lignin model compound III and IV, 0.26mol of guaiacol, 0.30mo1 of DMP, and 0.09 and 0.15mo1 of trimethoxyaretonphenone(TMAP) were produced respectively 3. Pyrolysis mechanism of lignin model compounds are dehydrated at first, and $\beta$-04 linkage cleavaged, and then guaiacol, DMP, DMAP and TMAP were produced. The above results show that lignin model compound I and II produce more aromatic compounds than lignin model compound III and IV. This is reason that veratryl unit structures may pyrolize easier than trimethoxyphenol unit structures. The closer research is proceeding.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.243-250
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• 2003

The present study discuss about numerical methods to analyze design parameters of pyrolysis-melting incineration system. Various numerical methods of different viewpoint are introduced to simulate the performance of the system. Process analysis of the overall system is the beginning procedure of basic design process. Heat and material flow of each element are connected and are influential to each other, hence, an appropriate process modeling should be executed to prevent from unacceptable process design concepts that may results in system failure. Models to simulate performance of each elementary facility generate valuable informations on design and operation parameters, and, derive the basic design concept to be optimized. A pyrolysis model derived from waste bed combustion model is introduced to simulate the mass conversion and heat transfer in the pyrolysis process. CFD(Computational fluid dynamics) is an effective method to optimize the thermal reacting flow in various reactors such as combustor and heat exchanger. Secondary air jets arrangement and the shape of the combustor could be optimized by CFD technology.

• New & Renewable Energy
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• v.19 no.3
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• pp.22-33
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• 2023

The number of fire and explosion accidents caused by pyrolysis oil and gas at waste plastic pyrolysis plants is increasing, but accident status and safety conditions have not been clearly identified. Therefore, the aim of the study was to identify the risks of the waste plastic pyrolysis process and suggest appropriate safety management measures. We collected information on 19 cases of fire and explosion accidents that occurred between 2010 and 2021 at 26 waste plastic pyrolysis plants using the Korea Occupational Safety and Health Agency (KOSHA) database and media reports. The mechanical, managerial, personnel-related, and environmental problems within a plant and problems related to government agencies and the design, manufacturing, and installation companies involved with pyrolysis equipment were analyzed using the 4Ms of Machines, Management, Man, and Media, as well as the System-Theoretic Accident Model and Processes (STAMP) methodology for seven accident cases with accident investigation reports. Study findings indicate the need for establishing legal and institutional support measures for waste plastic pyrolysis plants in order to prevent fire and explosion accidents in the pyrolysis process. In addition, ensuring safety from the design and manufacturing stages of facilities is essential, as are measures that ensure systematic operations after the installation of safety devices.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.4
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• pp.534-545
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• 2011

This paper describes the evaluation of kinetic parameters for pyrolysis and carbon char oxidation of residual oil. The non-isothermal pyrolysis of residual oil was carried out with TGA (Thermo-Gravimetric Analyzer) at heating rate of 2, 5, 10 and $20^{\circ}C/min$ up to $800^{\circ}C$ under N2 atmosphere. The first order and nth order pyrolysis models were used to fit the experimental data, and the nth order model was turned out to follow the experimental data more precisely than the first order model. For carbon char oxidation experiment, TGA and four heating rates used in pyrolysis experiment were also adapted. The kinetic parameters for the residual carbon char particle were obtained with three char oxidation model, that is, volume reaction, grain and random pore model. Among them, the random pore model described the char oxidation behaviour quite well, compared to other two models. The non-linear regression method was used to obtain kinetic parameters for both pyrolysis and carbon char oxidation of residual oil.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.5
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• pp.442-451
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• 2010

This paper describes the calculation method to obtain the product composition of coal pyrolysis at high pressure and high temperature. The products of coal pyrolysis should be determined for the coal gasifier simulation, and this is the first step of the coal gasifier simulation. The pyrolysis product distribution greatly affects the coal gasifier efficiency such as carbon conversion, cold gas efficiency and the syngas composition at the outlet of the gasifier. The present calculation method is based on the coal ultimate/proximate analysis and several correlations among gasifier pressure, coal properties and pyrolysis products. The calculated products for 5 coals have been compared with those from the commercial pyrolysis model.

• International Journal of Automotive Technology
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• v.4 no.1
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• pp.1-8
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• 2003

Wastes such as shredder dust of disposed vehicles can be decomposed into low calorific flammable gases by Pyrolysis gasification. A stationary electric Power generation using an internal combustion engine fuelled with the waste-pyrolysis gas is an effective way to ease both waste management and energy saving issues. The waste-pyrolysis gas mainly consists of H$_2$, CO, $CO_2$ and $N_2$. The composition and heating value of the gas generated depend on the conversion process and the property of the initial waste. This research analyzed the characteristics of the combustion and the exhaust emissions in a premixed charge spark ignition engine fuelled with several kinds of model gases, which were selected to simulate the pyrolysis-gases of automobile shredder dusts. The influences of the heating value and composition of the fuel were analyzed parametrically. Furthermore, optical analyses of the combustion flame were made to study the influence of the fuel's inert gas on the flame propagation.