• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.331-338
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• 2008

Coal-tar enamel, blown asphalt and polyethylene have been used as wrapping materials of steel pipe in Korea. Currently, every manufacturer produces wrapped steel pipes with different materials and methods, and little research has been performed to get on wrapping methods and materials. In this research, properties of wrapping material of steel pipe used for water supply have been evaluated. All of the materials tested in this work were found to meet the standard. Among the wrapping materials of steel pipe tested, blown asphalt and coal-tar enamel were reasonable in price, and their mechanical properties were excellent. The quality of the wrapped steel pipes was being melted easily in organic solvent. When coated thick, the load of the steel pipes was higher than necessary. Tensile strength of cathode exfoliation and PE 3-layer wrapping method was excellent. The pulling intensity of T-Die PE 3-layer was stronger than PE fluidized in PE wrapping method. Cathode exfoliation area was smaller than PE fluidized. Mechanical property and thermo-property of T-Die PE 3-layer were excellent and its anti-chemical property was great. Liquid epoxy can change the property of coating materials depending on the hardening condition and resin selection. Polyurethane used in this test showed a less adhesive strength with steel pipes than epoxy. Moisture absorbance rate was higher than Epoxy's, however. To utilize polyurethane as wrapping materials, basic property of the matter should be improved followed by finding the best suited coating condition. The method of PE 3-layer by extrude method appeared to be the best in this study. However, identification of other wrapping materials requires further additional tests.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.30-35
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• 1999

A simple, rapid, efficient method is for extraction of 13 synthetic water-soluble food colours (Tartrazine, Amarnth, Indigo carmine, New coccine, Sunset yellow FCF, Allura red AC, Eosine, Fast Green FCF, Brilliant Blue FCF, Erythrosine, Acid red, phloxine, Rose Bengal) by polyamide resin and for their quantitative by high performance liquid chromatography (HPLC). Colours (coal-tar dyes) were extracted with polyamide resin and then determinated by HPLC. The HPLC conditions using a reverse phase partition type column $(Nova-pak\;C_{18})$, photodiode array (PDA) detector and 1% Ammonium acetate / 60% acetonitrile in water as eluent, were acceptable for various kinds of colorants. By the use of the proposed method, a survey of coal-tar dyes was carried out on 20 samples and that were detected $4.76{\sim}133.47\;ppm$.

• Journal of the Korean Ceramic Society
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• v.30 no.10
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• pp.852-858
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• 1993

The effect of coal tar ptch-impregnated carbon materials which were made from petroleum coke was investigated at various pressure time and impregnation-sintering cycle. As a result, density and bending strength of the carbon materials were remarkably increased in the condition of pressure times of 5hrs and of the cycle of 3rd times. And the value of d002 and Lc of the graphitic carbon sintered at 230$0^{\circ}C$ shwoed 3.387$\AA$ and 167$\AA$, respectively.

• 대한예방의학회:학술대회논문집
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• 1996.10a
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• pp.285-286
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• 1996

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.415-420
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• 2016

To enhance electrochemical performances of anode materials, the surface of coal tar pitch (CTP) was modified by incorporating heteroatoms through chemical treatment with phosphoric acid ($H_3PO_4$). The prepared anode materials with modified CTP was analyzed by XRD, FE-SEM and XPS. The electrochemical performances of modified CTP were investigated by constant current charge/discharge test, rate performance, cyclic voltammetry and impedance tests using the electrolyte of $LiPF_6$ dissolved in the mixed organic solvents (ethylene carbonate : dimethyl carbonate = 1 : 1 vol% + vinylene carbonate 3 wt%). The coin cell using modified CTP ($H_3PO_4/CTP$ = 3 : 100 in weight) has better initial capacity and initial efficiency (489 mAh/g, 82%) than those of other composition coin cells. Also, it was found that the capacity retention was 86% after 30 cycles and the rate capability was 87% at 2 C/0.1 C.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.798-802
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• 1998

Carbon granules were prepared by granulating a mixture of coconut shell powder and coal tar solution, and then by carbonizing at different temperatures. To control micropores of the carbonized granules, the deposition time of benzene vapor under nitrogen atmosphere was varied. For each prepared sample, SEM morphology and true density were investigated. The adsorption rates on the granules were measured with respect to oxygen and nitrogen by means of the Cahn D-200 system. Diffusivity, selectivity and amount of equilibrium adsorption for the gases were obtained from the measurement of adsorption rate. Based on the analysis of the adsorption characteristics, the optimum temperature and the deposition time for preparation of the molecular sieve carbon granules were found to be $800^{\circ}C$ and 10 minutes, respectively. At these optimal conditions, the selectivity coefficient, 26.4, 0f oxygen and nitrogen was obtained.

• Korean Journal of Food Science and Technology
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• v.5 no.2
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• pp.89-94
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• 1973

Discoloration by heating and gamma-radiation of aqueous solutions of two coal-tar food dyes used in meat products was observed. Tartrazin with sodium tri-polyphosphate or cinnamon oil was slightly discolorized by heating at $75^{\circ}C$, but Amaranth was comparatively resistant. Effect of gamma rays of coal-tar food dyes was generally increased with irradiation doses, and especially by the addition of sodium tri-polyphosphate and cinnamon oil. This tendency was higher in Tartrazin than Amaranth. The addition of sodium nitrate and ascorbic acid, and storage at low temperature, however, seems to be effective in decreasing the discoloration of irradiated solutions.

• Carbon letters
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• v.16 no.2
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• pp.78-85
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• 2015

Activated carbons (ACs) were prepared by activation of coal tar pitch (CTP) in the range of $700^{\circ}C-1000^{\circ}C$ for 1-4 h using potassium hydroxide (KOH) powder as the activation agent. The optimal activation conditions were determined to be a CTP/KOH ratio of 1:4, activation temperature of $900^{\circ}C$, and activation time of 3 h. The obtained ACs showed increased pore size distribution in the range of 1 to 2 nm and the highest specific capacitance of 122 F/g in a two-electrode system with an organic electrolyte, as measured by a charge-discharge method in the voltage range of 0-2.7 V. In order to improve the performance of the electric double-layer capacitor electrode, various mixtures of CTP and petroleum pitch (PP) were activated at the optimal activation conditions previously determined for CTP. Although the specific capacitance of AC electrodes prepared from CTP only and the mixtures of CTP and PP was not significantly different at a current density of 1 A/g, the AC electrodes from CTP and PP mixtures showed outstanding specific capacitance at higher current rates. In particular, CTP-PP61 (6:1 mixture) had the highest specific capacitance of 132 F/g, and the specific capacitance remained above 90% at a high current density of 3 A/g. It was found that the high specific capacitance could be attributed to the increased micro-pore volume of ACs with pore sizes from 1 to 2 nm, and the high power density could be attributed to the increased meso-pore volume.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.408-415
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• 2014

In order to prepare high-quality activated carbons (ACs), coal tar pitch (CTP), and mixtures of CTP and petroleum pitch (PP) were activated with KOH. The ACs prepared by activation of CTP in the range of $700{\sim}1000^{\circ}C$ for 1~5 h had very porous textures with large specific surface areas of $2470{\sim}3081m^2/g$. The optimal activation conditions of CTP were determined as CTP/KOH ratio of 1:4, activation temperature of $900^{\circ}C$, and activation time of 3 h. The obtained AC showed the highest micro-pore volume, and pretty high specific surface area and meso-pore volume. The micro-pore volumes and specific areas of activated mixtures of CTP and PP were similar to each other but the meso-pore volume could be increased. In order to change the degree of crystallinity of precursors before KOH activation process, the CTPs were carbonized in the range of $500{\sim}900^{\circ}C$. As the carbonization temperature increased, the specific surface area and pore volume of the activated ACs with the same activation conditions for CTP decreased dramatically. It was demonstrated that the increased pore size distribution of AC electrodes in the range of 1 to 2 nm plays an important role in the performance of electric double-layer capacitor.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1065-1073
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• 2006

The unturned carbon in fly ash, recently occurred in the coal-fired Yong Hung power station, caused some problems in ash utilization and boiler efficiency. This paper describes the analysis of unburned carbon and six coals, some tests performed at Yong Hung Boiler, and the results of combustion modification for the reduction of unburned carbon in fly ash. From the physical and chemical analysis of unburned carbon in fly ash, most particles were turned out to be hollow cenosphere and agglomerated soot particles. The sooting potential from six coals used in the plant were investigated with CPD(Chemical Percolation Devolatilization) model. The results showed that the higher potential was presented to Peabody, Arthur, Shenhua coals rather than other coals. It was necessary to measure the coal flow rates at each coal feeding pipe for four burner levels since they affect the extent of mixing of soot with oxidant, in turn, the oxidation rate of soot particles. The unbalance in coal flow rate was found in several coal pipes. We successfully reduced unturned carbon in ash by increasing the excess air and changing the SOFA's yaw angle.