• Clean Technology
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• v.19 no.1
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• pp.30-37
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• 2013

Low-rank coal with high water content (32.3 wt%) was dried by fry drying, and the fuel characteristics of the dried coal from which the oil was separated by using a high-speed centrifugal separator were analyzed. After fry drying for 6 min and 10 min, the water content decreased to 5.0 wt% and 4.2 wt% respectively. The higher calorific value (HCV) of the coal increased remarkably after fry drying, from 11,442.0 kJ/kg-wet. The oil content of the fry-dried coal was 15.0 wt% and it decreased with an increase in the reheating temperature: 9.7 wt% at $80^{\circ}C$ to 9.3 wt% at $100^{\circ}C$, and then to 8.5 wt% at $120^{\circ}C$. The recovered oil could then be reused. According to of thermogravimetric analysis (TGA), there was no difference in the weight loss patterns of the coal samples with different coal diameters at a reheating temperature of $120^{\circ}C$. This was because the amount of oil separated by the centrifugal separator was affected by the reheating temperature rather than the coal diameter. And derivative thermogravimetry (DTG) curves of raw coal before the fry-drying process, a peak is formed at $400^{\circ}C$ in which the volatile matter is gasified. In case of the fry-dried coal, the first peak is generated at $350^{\circ}C$, and the second peak is generated at $400^{\circ}C$. The first peak is caused by the oil that is replaced with the water contained in the coal during the fry-drying process. Further, the peaks of the coal samples in which the oil is separated at a reheating temperature of $80^{\circ}C$, $100^{\circ}C$, $120^{\circ}C$, respectively are smaller than that of the coal in which the oil is not separated, and this is caused by that the oil is separated by the centrifugal separator.

• Journal of Hydrogen and New Energy
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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.

• Asian Journal of Atmospheric Environment
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• v.7 no.1
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• pp.48-55
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• 2013

The purpose of this study was to develop a $CO_2$ emission factor for refuse plastic fuel (RPF) combustion facilities, and calculate the $CO_2$ emissions from these facilities. The $CO_2$ reduction from using these facilities was analyzed by comparing $CO_2$ emission to facilities using fossil fuels. The average $CO_2$ emission factor from RPF combustion facilities was 59.7 Mg $CO_2$/TJ. In addition, fossil fuel and RPF use were compared using net calorific value (NCV). Domestic RPF consumption in 2011 was 240,000 Mg/yr, which was compared to fossil fuels using NCV. B-C oil use, which has the same NCV, was equal to RPF use. In contrast, bituminous and anthracite were estimated at 369,231 Mg/yr and 355,556 Mg/yr, respectively. In addition, the reduction in $CO_2$ emissions due to the alternative fuel was analyzed. $CO_2$ emissions were reduced by more than 350 Mg $CO_2$/yr compared to bituminous and anthracite. We confirmed that using RPF, an alternative fuel, can reduce $CO_2$ emissions.

• International Journal of Automotive Technology
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• v.6 no.5
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• pp.437-444
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• 2005

Unburned hydrocarbon (UBHC) emissions from gasoline engines remain a primary engineering research and development concern due to stricter emission regulations. Gasoline engines produce more UBHC emissions during cold start and warm-up than during any other stage of operation, because of insufficient fuel-air mixing, particularly in view of the additional fuel enrichment used for early starting. Impingement of fuel droplets on the cylinder wall is a major source of UBHC and a concern for oil dilution. This paper describes an experimental study that was carried out to investigate the distribution and 'footprint' of fuel droplets impinging on the cylinder wall during the intake stroke under engine starting conditions. Injectors having different targeting and atomization characteristics were used in a 4-Valve engine with optical access to the intake port and combustion chamber. The spray and targeting performance were characterized using high-speed visualization and Phase Doppler Interferometry techniques. The fuel droplets impinging on the port, cylinder wall and piston top were characterized using a color imaging technique during simulated engine start-up from room temperature. Highly absorbent filter paper was placed around the circumference of the cylinder liner and on the piston top to collect fuel droplets during the intake strokes. A small amount of colored dye, which dissolves completely in gasoline, was used as the tracer. Color density on the paper, which is correlated with the amount of fuel deposited and its distribution on the cylinder wall, was measured using image analysis. The results show that by comparing the locations of the wetted footprints and their color intensities, the influence of fuel injection and engine conditions can be qualitatively and quantitatively examined. Fast FID measurements of UBHC were also performed on the engine for correlation to the mixture formation results.

• Corrosion Science and Technology
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• v.11 no.5
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• pp.196-204
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• 2012

Corrosion failure of petrochemical facilities is one of the difficulties in maintenance, since operating conditions of crude oil production, storage, and refinement are very aggressive. UNS N08810, which has been used for crude oil transportation pipes and storage tanks in petrochemical industries, shows good resistance to general corrosion and localized corrosion in several environments. Among its environments, UNS N08810 showed better corrosion resistance in fuel gas containing sulfuric acid and phosphoric acid and sulfur. However, ductility and toughness at high temperature over about $500^{\circ}C$ were greatly reduced due to microstructural change. In general, welding process is the representative method to join the parts in industrial components. Because the alloy by welding can be sensitized and corroded, the manufacturing process should be controlled. In this work, UNS N08810 was used and heat treatment conditions including solution and stabilization treatments were controlled. Oxalic acid etch test by ASTM A262 Practice A was done to evaluate the qualitative sensitization in room temperature. Huey test by ASTM A262 Practice C was done to evaluate the intergranular corrosion rate in boiling 65% $HNO_3$ solution. Also, the microstructure by thermal history was analyzed. Experimental alloy showed high intergranular corrosion rate and its corrosion mechanism was elucidated.

• Journal of Hydrogen and New Energy
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• v.19 no.1
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• pp.56-63
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• 2008

In this study, thermochemical degradation of hemicellulose by Acetone-Solvolysis, the effects of reaction temperature, conversion yield, degradation properties and degradation products were investigated. Experiments were performed in a tube reactor by varying reaction temperature from $200{\circ}C$ to $400{\circ}C$ at 40 min of reaction time. The liquid products from pyrolysis-liquefaction of hemicellulose contained various kinds of ketones. ketones, as 4-methyl-3-penten-2-one, 3-methylene-2-pentanone, 22,6-dimethyl-2, 5-heptadien-4-one, 4-methyl-2-pentanone, 5-methyl-2-hexanone, 3,5,5-trimethyl-2-cyclohexen-1-one, and bezenes. as 1,4-dimethylbenzene, 1-methyl-2-(1-methylethyl)-benzene, 1,4-dimethyl-2-(2-methylpropyl)benzene, 4-secbutyl-ethyl benzene, could be used as high-octane-value fuels and fuel additives. Combustion heating value of liquid products from thermochemical conversion processes of hemicellulose was in the range of $6,680{\sim}7,170cal/g$. After 40min of reaction at $400{\circ}C$ in Acetone-Solvolysis of hemicellulose, the energy yield and mass yield was as high as 72.2% and 41.2g oil/100g raw material, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.2
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• pp.59-72
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• 2009

In order to utilize sewage sludge as a heat source of energy, it goes without saying that the fuel should be clean and pose no threat to the environment. As a consequent, it should not contain even minute quantities of heavy metals / impurities. The SOCA (Sludge-Oil-Coal- Agglomerates) fuel can meet all these requirements. SOCA being a solid fuel can be gasified for the production of clean energy. Wet catalytic gasification is the most appropriate process for SOCA containing nearly 60% water. It is important to note that the SOCA thus obtained inherits ca. 40~50% of sulfur from the coal used. It can poison the catalyst during catalytic gasification process. Consequently, it becomes important to choose a proper catalyst for the gasification. Calcium was found to be ideal choice as a catalyst for the gasification of SOCA. The optimal gasification was performed at $850^{\circ}C$ with water vapor. The role of fuel-N is of utmost importance in the gasification of SOCA. The gasification should be controlled to reduce the production of HCN to a minimum and enhance its conversion to $N_2$ and/or $NH_3$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.9-15
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• 2018

The turbochargers, which are used widely in diesel and gasoline engines, are an effective device to reduce fuel consumption and emissions. On the other hand, turbo-lag is one of the main problems of a turbocharger. Bearing friction losses is a major cause of turbo lag and is particularly intense in the lower speed range of the engine. Current turbochargers are mostly equipped with floating bearings: two journal bearings and one thrust bearing. This study focused on the bearing friction at the lower speed range and the experimental equipment was established with a drive-motor, load-cell, magnetic coupling, and oil control system. Finally, the friction losses of turbochargers were measured considering the influence of the rotating speed from 30,000rpm to 90,000rpm, oil temperature from $50^{\circ}C$ to $100^{\circ}C$, and oil supply pressure of 3bar and 4bar. The friction power losses were increased exponentially to 1.6 when the turbocharger speed was increased. Friction torques decreased with increasing oil temperature and increased with increasing oil pressure. Therefore, the oil temperature and pressure must be maintained at appropriate levels.

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.199-204
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• 2008

Hemicellulose, consisteing of pentose as xylose and mannose, is usable as high octane fuels and heavy oil additives if depolymerized to monomer unit. In this study, thermochemical degradation by pyrolysis-liquefaction of hemicellulose, the effects of reaction temperature, conversion yield, degradation properties and degradation products were investigated. Experiments were performed in a tube reactor by varying reaction temperatures from $200^{\circ}C$ to $400^{\circ}C$ at 40 min of reaction time. The liquid products from pyrolysis-liquefaction of hemicellulose contained various kinds of ketones. Ketones, as 2,3-dimethyl-2-cyclopenten-1-one, 2,3,4-trimethyl-2-cyclopentan-1-one, and 2-methyl-cyclopentanone, could be used as high-octane-value fuels and fuel additives. However, phenols are not valuable as fuels. Combustion heating value of liquid products obtained from thermochemical conversion processes of hemicellulose was in the range of 6,680~7,170 cal/g. After 40 min of reaction at $400^{\circ}C$ in pyrolysis-liquefaction of hemicellulose, the energy yield and mass yield were as high as 72.2% and 41.2 g oil/100 g raw material, respectively.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.38-44
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• 2000

Compared to other waste, waste tire has much discharge quantity and calorie. When we use waste heat from waste tire, it can be definitely better substitute energy than coal and anthracite in high oil price age. To use as a basic data for providing low cost and highly effective heating system, following conclusion was founded. Annual waste tire production was 19,596 million in 1999, Recycling ratio was almost 55% and more than 8.78 million was stored. Waste tire has lower than 1.5% sulfur contain ratio which is resource of an pollution, So it is a waste fuel which can be combustion based on current exhaust standard value without any extra SOx exclusion materials. Waste tire has 9,256Kcal/kg calorific value and it is higher than waste rubber, waste rubber, waste energy as same as B-C oil. When primary and second air quantity was 1.6, 8.0 Nm$^3$/min, dry gas production time was 270min and total combustion time was 360 min. In the SOx, NOx, HC of air pollution material density were lower than exhaust standard value at the back of cyclone and dusty than exhaust standard value without dust collector.