• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.47-58
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• 2005

Rice straw is one of the main renewable energy sources in Korea, and bio-oil is produced from rice straw with a lab. scale plant equipped mainly with a fluidized bed and a char removal system. We investigated how the reaction temperature affected the production of bio-oil and the efficiency of a char removal system. To elucidate how the temperature depended on the production of bio-oil, experiment were conducted between $450^{\circ}C\;and\;600^{\circ}C$ with a feed rate of about 300g/h. The mass balance was established in each experiment, and the produced gas and oil were analyzed with the aid of GCs and a GC-MS system. The char removal system is composed of a cyclone and a hot filter. In the experiments, we observed that the optimum reaction temperature range for the production of bio-oil is between $450^{\circ}C\;and\;500^{\circ}C$.

• Membrane Journal
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• v.13 no.4
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• pp.291-299
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• 2003

Polymer membranes such as poly(1-trimethylsilyl-1-propyne)-polyetherimide (PTMSP-PEI) and poly(dimethylsiloxane)- polyetherimide (PDMS-PEI) composite membrane were prepared by solution casting method. To investigate the characteristics of these membranes, the analytical methods such as FT-IR, $^1H-NMR,$ DSC, TGA, GPC, and SEM have been utilized. The number-average (equation omitted) and weight-average (equation omitted) molecular weight of PTMSP were 477,920 and 673,329 respectively. The glass transition temperature ($T_g$) of PTMSP was $224^{\circ}C.$ The separation of the gas mixture ($H_2/N_2$) through the composite membranes were studied as a function of pressure. The separation factor (${\alpha}, {\beta},$ quation omitted) of the composite membranes used in this work increased as the pressure of permeation cell increased. The real separation factor (${\alpha}$), head separation factor (${\beta}$), and tail separation factor (equation omitted) of PTMSP-PEI composite membrane were 2.28, 1.17, and 1.96 respectively at ${\Delta}P$ 30psi and $25^{\circ}C.$ (${\alpha}, {\beta}$ and equation omitted of PDMS-PEI composite membrane were 3.70, 1.53, and 2.42 respectively at ${\Delta}P$ 30psi and $25^{\circ}C$.

• Journal of Energy Engineering
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• v.2 no.2
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• pp.194-199
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• 1993

Gas diffusion passes are introduced to catalyst layer so as to enlarge reaction region in cathode and anode and then improve electrode performances. The catalyst layer was manufactured with PTFE/carbon (none catalyst loaded) for gas diffusion and Pt/carbon (10 w/o Pt catalyst loaded) by varing the mixing ratio of (PTFE/carbon) to (Pt/carbon) by catalyst powdering method. The electrodes made by mixing Pt(10 w/o)/carbon powders and PTFE/carbon powders containing 60 w/o PTFE at the ratio of 7 : 3 showed the best electrode performances. It was known that by comparing the porosities to electrode performances the electrode performances were increased as both macro pore for gas diffusion and micro pore for electrolyte intrusion were formed much more. The platinum catalyst content in electrode was 0.2 mg/$\textrm{cm}^2$ and the PTFE content was 42 w/o. The electrode performance in unit cell was 220 ㎃/$\textrm{cm}^2$/0.7 V at operating temperature of 150$^{\circ}C$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.10
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• pp.947-955
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• 2010

Most oil and gas reservoirs, which have some light hydrocarbon components, show sensitive phase behavior in response to changes in the composition of the internal fluid. When evaluating and developing plans for oil and gas fields, flash calculation, PVT analysis, and saturation-property calculation are necessary for analyzing reservoir characteristics and pipeline flows. In general, the determination of saturation properties such as dew point and bubble point is considered a difficult task because of the poor convergence of the calculation methods. In this study, several new initial-value-guessing methods and root-finding methods are proposed; parametric analysis were carried out to verify the improvement in convergence. Finally, these new ideas and methods were successfully applied to the new GUI based multi-phase behavior simulator.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.3-9
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• 1998

This paper presents soil-gas surveying technique to delineate an area contaminated with volatile organic compounds, which are common solvents and constituents of gasoline. The sampling method of soil-gas surveying is 1) grab sampling, which actively takes sample using a pump, or 2) passive sampling, which takes sample through diffusion in a trap filled with absorbent. The grab sampling shows the level of contamination at a certain location at a certain time, while the passive sampling shows the change in the contamination at a certain location. The analysis of soil gas can be performed with 1) a small portable detectors such as PID (photoionization detector) or FID (flame-ionization detector) to measure the total hydrocarbon in the soil gas, 2) a gas detector tube, which is filled with indicator reagents and changes its color with concentrations of the gas of interest, or 3) a portable GC (gas chromatograph), which can analyze different compounds simultaneously. The soil-gas surveying technique is a much less expensive method to investigate area contaminated volatile organic compounds and thus can be used as a screening tool to identify an area, which needs to be further investigated.

• Clean Technology
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• v.17 no.1
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• pp.62-68
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• 2011

Hydrodynamic characteristics in multistage annular type fluidized bed (riser: $0.01{\times}0.025{\times}2.8m^3$, J-valve: $0.009{\times}0.015m^2$)were investigated. Glass beads ($d_p=101{\mu}m$, ${\rho}_b=1,590kg/m^3$, $U_{mf}=1.25{\times}10^{-2}m/s$, Geldart classification B) was used as a bed material. Accumulated weight by the electronic balance was measured to determine the solid flow rate in batch-type. In circulation condition, we measured the accumulated weight of particle transported from riser. At the steady state condition, solid circulation rate was calculated from time interval of the heated bed material passing between two thermocouples. Solid flow rate increased with increasing inlet gas velocity ($1.2-2.6U_{mf}$) and the static bed height (z, 0.24-0.68 m) from 2.2 to 23.4 kg/s. However, mean residence time decreased with increasing inlet gas velocity ($1.2-2.6U_{mf}$) and the static bed height (z, 0.24-0.68 m) from 1,438 to 440 s. The solid holdup in the riser was determined by measuring pressure differences according to the riser height. These results showed a similar trend to that of simple exponential decay type except for the top section of the riser. To verify the gas bypassing from top bubbling beds to middle bubbling beds, $CO_2$ gas was injected by tracer gas in constant ratio, and then was measured $CO_2$ concentration in outlet gas by gas chromatography. Gas bypassing occurred below 2.6% which is negligible value.

• Korean Journal of Food Science and Technology
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• v.13 no.1
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• pp.37-42
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• 1981

Polar lipids of the total lipid extracted from 4 representative varieties of barley grown in Korea and their corresponding malt were studied. The average content of glycolipids and phospholipids in barley were 8.9 and 17.3% and their average content of malt were 12.3 and 19.2%, respectively. Among the glycoliplds of the barley, digalactosyl diglycerides and monogalactosyl diglycerides were the major components, and the malts showed somewhat lower amounts of those components. Steryl glycosides and cerebrosides were the minor components of the glycolipids, and malts of the barley showed somewhat increased amounts of those components. Phosphatidyl cholines, lysophosphatidyl cholines, diphosphatidyl glycerols, and phosphatidyl ethanolamines were the major components of the phospholipids for the barley and represented 85 to 90% of the total phospholipids. The malts had lower amounts of phosphatidyl cholines and the lyso analog, and higher amounts of phosphatidyl ethnolamines and diphosphatidyl glycerols. The fatty acid composition in the glycolipids and phospholipids were similar to the pattern in those of the neutral lipids. But glycolipids and phospholipids fractions contained a higher percent of linoleic and palmitic acid than other lipid fractions, respectively.

• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.62-67
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• 1994

Quality change of Kimchi packaged with Ny/PE, Ny/CPP (PPtray+Ny/CPP cover), Cryovac BK-1, BK-4, and PET/Al/PE film was observed during storage at $5^{\circ}C$ (97%RH) and $20^{\circ}C$ (76%RH). To evaluate quality change of Kimchi, gas composition of package, pH, acidity, color, growth of lactic acid bacteria, and sensory score were measured periodically. Regarding to gas composition of package, Kimchi packaged with PET/Al/PE showed higher oxygen concentration at the beginning of storage than the others; carbon dioxide concentration was almost 100% at the end of storage. Carbon dioxide concentration of Kimchi packaged with Cryovac BK-1 and BK-4 which has higher gas permeability than the others, was increased to a maximum and then decreased due to permeation of gas during storage; oxygen concentration was increased. Unlike Kimchi packaged with Ny/PE, Ny/CPP, and PET/Al/PE, package swelling was not observed in Kimchi packaged with Cryovac BK-1 and BK-4 during storage. Although pH change was not significant depending on the packaging material, Kimchi packaged with Cryovac BK-1 and BK-4 showed lower pH value and higher acidity than those of the others. Color change of Kimchi was different depending on the packaging material during storage. Difference of the growth of lactic acid bacteria and sensory evaluation were not significant among Kimchi packaged with different packaging material during storage at either temperature. In conclusion, the effect of packaging materials on the quality change of Kimchi was not significant; however, to prevent from swelling of packaged Kimchi which is one of the most serious problem during storage and distribution, might be avoided by using relatively high $CO_2$ permeable film than high gas barrier film.

• Food Science and Preservation
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• v.8 no.3
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• pp.239-245
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• 2001

The CA(Controlled Atmosphere) storage of cherry tomatoes were carried out under seven gas compositions including air. The weight loss of cherry tomatoes progressively increased with storage time. In the case of cherry tomatoes stored under CA conditions, increment of weight loss was reduced. However, cherry tomatoes (in air) tut about 15% weight at the end of storage. In CA stored cherry tomatoes lost about 10% weight at the same time. General trend was a decrease in titratable acidity with storage time. In air md 6.4% O$_2$, 4.2% CO$_2$, titratable acidity was lower than that in other storage conditions. During storage of cherry tomatoes, soluble solids increased till 8 days of storage, and then decreased. Stored cherry tomatoes in air and 6.4% O$_2$+4.2% CO$_2$ have lower values. Lycopene contents of cherry tomatoes with 6% O$_2$ storage condition increased and cherry tomatoes with 1% O$_2$+6% CO$_2$ and 3% O$_2$+3.1% CO$_2$maintained s initial contents. In air, flesh firmness decrease till 8 days, and then increase. At 1% O$_2$+6% CO$_2$ ethanol contents were ten times to that of other experimental conditions. Air and 6% O$_2$+7.8% CO$_2$ condition had lowest value for the ethanol content. In changes of organic acid and citric acid decreased slowly during storage, malic acid in air and below 3% O$_2$was disappeared at 8 days. Above 4% O$_2$concentration malic acid contents were maintained till 16 days. In over all acceptability, air and 6.4% O$_2$+7.8% CO$_2$ condition took a good score from the panel. Quality of stored cherry tomatoes was not edible condition in 1% O$_2$+6% CO$_2$. CA storage cherry tomatoes took a good score in firmness and juiciness where as control received good score in color and sweetness. This result was explained that in air ad 6.4% O$_2$+7.8% CO$_2$stored cherry tomato was ripened and full color development, but in CA was break stage because of suppressed ripening.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.433-437
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• 2013

Electrical discharge plasma created in a multi-channel porous ceramic membrane-supported catalyst was applied to the decomposition of a volatile organic compound (VOC). For the purpose of improving the oxidation capability, the ceramic membrane used as a low-pressure drop catalyst support was loaded with zinc oxide photocatalyst by the incipient wetness impregnation method. Alternating current-driven discharge plasma was created inside the porous ceramic membrane to produce reactive species such as radicals, ozone, ions and excited molecules available for the decomposition of VOC. As the voltage supplied to the reactor increased, the plasma discharge gradually propagated in the radial direction, creating an uniform plasma in the entire ceramic membrane above a certain voltage. Ethylene was used as a model VOC. The ethylene decomposition efficiency was examined with experimental variables such as the specific energy density, inlet ethylene concentration and zinc oxide loading. When compared at the identical energy density, the decomposition efficiency obtained with the zinc oxide-loaded ceramic membrane was substantially higher than that of the bare membrane case. Both nitrogen and oxygen played an important role in initiating the decomposition of ethylene. The rate of the decomposition is governed by the quantity of reactive species generated by the plasma, and a strong dependence of the decomposition efficiency on the initial concentration was observed.