• Carbon letters
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• v.25
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• pp.78-83
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• 2018

Pyrolyzed fuel oil (PFO) and coal tar was blended in the feedstock to produce pitch via thermal reaction. The blended feedstock and produced pitch were characterized to investigate the effect of the blending ratio. In the feedstock analysis, coal tar exhibited a distinct distribution in its boiling point related to the number of aromatic rings and showed higher Conradson carbon residue and aromaticity values of 26.6% and 0.67%, respectively, compared with PFO. The pitch yield changed with the blending ratio, while the softening point of the produced pitch was determined by the PFO ratio in the blends. On the other hand, the carbon yield increased with increasing coal tar ratio in the blends. This phenomenon indicated that the formation of aliphatic bridges in PFO may occur during the thermal reaction, resulting in an increased softening point. In addition, it was confirmed that the molecular weight distribution of the produced pitch was associated with the predominant feedstock in the blend.

• Clean Technology
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• v.3 no.1
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• pp.96-105
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• 1997

The objectives of this study were to investigate $SO_2$ removal efficiency of anthracite - bituminous coal blend combustion in a fludized bed coal combustor with Ca/S, anthracite ratio, bed temperature, and waste paper sludge particle size. The experimental results were presented as follow ; the effect of the desulfurization by the particle size of waste paper sludge was a great and $SO_2$ removal efficiency was heigest in paper sludge dia $1016{\mu}m$. And the difference of $SO_2$ removal efficiency according to air velocity was not too large. As Ca/S mole ratio incresed, $SO_2$ removal efficiency incresed rapidly up to Ca/S mole ratio 3 while the desulfurization rates did not increse too largely in the range of more than the level. The bed temperature had a great deal of effect on the desulfurization rate. So the $SO_2$ removal efficiency was a graet using waste paper sludge that the properbility of paper sludge as sorbent was conformed.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.517-523
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• 1997

We have been studied that combustion efficiency and the production of air pollution of anthracite-bituminous coal blend in a fluidized bed coal combustor. Also, the reaching time of steady state condition have been studied. This experimental results are presented as follows. As the height of fluidized bed combustor becomes higher, the concentrations of $SO_2$ and NOx mainly increased. Also, as anthracite fraction increased, the emission of $SO_2$ concentration was increased but, the variation of $NO_X$ concentration was negligible according to anthracite fraction. When anthracite fraction ratio was increased, elutriation rate was increased and exit combustible content over feeding combustible content was increased. Regardless of anthracite fraction ratio the uncombustible weight percentage according to average diameter of elutriation particles were approximately high in the case of fine particles. Over bed temperature $850^{\circ}C$ and excess air 20%, the difference of combution at the velocity 0.3m/s, bed temperature $850^{\circ}C$, the excess air 20%.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.99-106
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• 2017

In this study, mixed catalytic char gasification of Indonesia low-rank coal Kideco was investigated under nitrogen atmosphere and isothermal conditions at a fixed reactor. The effects of the temperature were investigated at various temperature (700, 750, 800, $850^{\circ}C$). The effects of blend ratio of catalysts ($K_2CO_3$, Ni) were investigated with different blend ratios (1:9, 3:7, 5:5, 7:3 and 9:1). The sample was prepared by mixing with $K_2CO_3$ physically and by ionexchange method with Ni. The data from thermogravimetric analyzer and gas chromatography were applied to four gassolid reaction kinetic models including shrinking core model, volumetric reaction model, random pore model and modified volumetric reaction model.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.121-126
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• 2013

The objective of this research is to predict the TG curve of blends of bituminous coal and sub-bituminous coal during devolatilization. TSL (Thermal Shock Large) TGA was used for Experiments, and Coats-redfern method was used for reaction order calculation. Based on reaction order, sum method was verified to be suitable for a single coal, then, prediction and comparison of TG curve of coal blends was conducted using both of WSM (Weight Sum Method) and MWSM (Modified Weight Sum Method), where the latter was developed in this research. The presented experiment results and WSM & MWSM were showed to be reasonable using linear least square method. MWSM performed more accurately than WSM for the case that TG curve had different slopes and the case that sharp weight loss happened due to release of volatile matter. The results showed that it's possible to predict the thermal behavior of coal blends during devolatilization based on the thermal behavior of single coals.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.39-41
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• 2012

The influence of coal blending methods such as out-furnace (external or pre-mixed) blending and in-furnace (initially non-mixed) blending with different excess oxygen (highest, medium, and lowest stoichiometric conditions) on unburned carbon and NOx emissions of blend combustion in an entrained flow reactor (EFR) has been analyzed, using experimental and numerical approaches for binary coals used by Korean power plants. The results confirm that under the medium condition, contrasting processes such as reactive and un-reactive effects occur with SBRs in the out-furnace blending method. The in-furnace blending method results in an improvement in the efficiency of unburned carbon fractions and a further reduction in the NOx emission. Under the highest condition, the unburned carbon fraction in both the out-furnace and the in-furnace blending methods corresponds with the tendency under the medium condition with contrasting processes of lower magnitude, whereas the NOx emission in the highest condition increases slightly. Under the lowest conditions, the unburned carbon fraction in the out-furnace blending method gradually decreases as SBR decreases, without a competition effect. The reduction of NOx emission under the lowest conditions is more effective than those under other conditions for the two blending methods because of a homogeneous and heterogeneous NOx reduction mechanism.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.68-74
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• 2012

Sub-bituminous coals have been used increasingly in coal-fired power plants with a proportion of over 50% in the blend with bituminous coals. As a result, the unburned material in fly ash has increased and is causing problems in utilizing the fly ash as an additive for concrete production. In this study, analysis of fly ash obtained from a 500 MWe power plant was carried out and unburned material in the fly ash found to be soot. The coals used in the plant were analyzed with CPD model to investigate the sooting potential depending on the coal type and blending ratio.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.1
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• pp.81-89
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• 2018

Fuel blend technique is one of the most effective way of using biomass to replace the coal. Many studies on combustion characteristics with coal and biomass blends have been conducted. In this study, char reactivity and emission characteristics of coal (Suek) and biomass (EFB) blends has been investigated by TGA and DTF to evaluate the applicability of the pre-treated (torrefaction, ash removal technology) EFB to pulverized coal boiler. In all blending cases, char reactivity improved as the blending ratio increases (10, 20, and 30%), especially torrefied EFB blended at 30%. Also, unburned carbon decreased as the blending ratio increases in all types of EFB. NOx emission showed the increase and decrease characteristics according to the content of fuel-N of raw EFB and torrefied EFB. But the amount of NOx emission at ashless EFB blends is greater than that of Suek despite of lower fuel-N. It indicated that co-firing effect of using the pretreatment biomass fuel is relatively better than those of the untreated biomass fuel about char reactivity and emission characteristics.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.2
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• pp.133-140
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• 2008

A reduced chemical kinetic mechanism is developed in order to predict the flame phenomena in premixed $CO/H_2/Air$ flames at atmospheric pressure, aimed at studying the coal gas combustion for the IGCC applications. The reduced mechanism is systematically derived from a full chemical kinetic mechanism involving 11 reacting species and 66 elementary reactions. This mechanism consists of four global steps, and is capable of explicitly calculating the concentration of 7 non-steady species and implicitly predicting the concentration of 3 steady state species. The fuel blend contains two fuels with distinct thermochemical properties, whose contribution to the radical pool in the flame is different. The flame speeds predicted by the reduced mechanism are in good agreement with those by the full mechanism and experimental results. In addition, the concentration profiles of species and temperature are also in good agreement with those by the full mechanism.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.9-17
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• 2016

In this study, a method for CO reduction using char-coal combustions was developed with lignin and glycerin as combustion improvers. The relationship between CO emission and the combustion improvers was confirmed by measuring the CO concentration. The experiment to determine the combustion characteristics was conducted using glycerin, which shows high combustibility at low temperatures, impregnated with lignin, which has a specific surface area. The combustibility, volatility, and CO concentration were measured using thermo-gravimetric analysis(TGA), and gas chromatography-mass spectrometry(GC-MS). This study presents the optimal CO reduction ratio, which occurred when the combustible material contained a 20% blend of combustion improvers. This resulted in a 20-30% CO reduction rate compared to that achieved with normal char-coal.