• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.482-486
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• 2013

Recently, biohydrocarbons are gathering an interest as a new bioenergy due to the versatile applicability. In the present work, a process is proposed for the recovery of lipids from Recombinant E. coli MG1655 which provides longer chain fatty acids. After the growth of the recombinant E. coli, the cells were disrupted by high pressure homogenizer for obtaining intracellular lipids and the resulting solutions were centrifuged and extracted. For the efficient cell disruption with high pressure homogenizer, the pressure higher than 5,000 psi was required. In addition, under the conditions of applied pressure 5,000 to 20,000 psi, 1~3 pass homogenizing was enough for the more than 90% cell disruption. As organic solvents for extraction of lipid, hexane/isopropyl alcohol and ethyl acetate/ethanol systems showed excellent extracting power. With these solvent systems, the 60% lipid could be recovered. Moreover it was found that the extracted lipids contained long-chain fatty acids such as $C_{12}$, $C_{14}$, $C_{16}$ and $C_{18}$.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.359-373
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• 2013

Shale is considered as a source rock for conventional oil and gas exploration and development because shale is fine-grained detrital sedimentary rock which can preserve the organic matter better. Shale has a good sealing capacity for the petroleum trap due to its low permeability. Commercial recoveries of gas from shale in the North America based on the development of technologies of horizontal drilling and hydraulic fracturing reveal that shale also function as a effective reservoir rock. Geochemical techniques to evaluate generation potential of the hydrocarbons from organic matter in the source rocks can be applied for the exploration of the shale gas resources. To evaluate shale gas resources, it is important to understand various geochemical processes and shale characteristics controlling generation, storage and estimation of shale gas reserves. In this paper, the generation mechanism of the oil and gas from organic matter is reviewed, and geochemical techniques which can be applied for the evaluation and characterization of shale gas are introduced.

• The Korean Journal of Petroleum Geology
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• v.14 no.1
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• pp.36-44
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• 2008

Natural gas in tight reservoirs, one of unconventional hydrocarbon resources, has become a significant exploration and exploitation targets. Tight gas reservoirs are the gas-bearing rocks that commonly have a permeability of less than 0.1 millidarcy (mD). Tight gas reservoirs are characterized by extensive and deep locations as well as abnormal pressure such as over- or under-pressure. The tight gas reservoirs are independent of structural or stratigraphic traps, whereas conventional gases normally occur at these traps. Tight gas reservoirs can be productive when stimulated by hydraulic fracturing. Better production areas within the tight reservoir beds are referred to as sweet spots that are commonly caused by natural fractures, which should be understood and identified to enhance the recovery of the gas from tight reservoirs. The exploration and production techniques allow the commercial production of tight gas, one of environmentally friendly resources. Slant and horizontal wells have best production when they intersect the fractures. Gas production from the tight reservoirs has rapidly grown in U.S. and Canada. Indeed, the U.S. gas production of tight sandstones increases from 11.1% in 1990 to 24.1% in 2005. The presence of tight gas reservoirs has been suggested on the Korean offshore block 6-1. Paradigm shift from conventional to unconventional tight reservoir is required to develop the tight gas from the block.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.624-629
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• 2015

A biosensor including the homogenized tissue of mugwort embedded in carbon paste, which senses hydrogen peroxide, was constructed and its electrochemical properties were validated using voltammetry. The good linearity of Hanes-Woolf plot implied that the reduction reaction of substrate was catalyzed by mugwort peroxidase at the electrode surface. Also the small value of symmetry factor, 0.28, indicated that electrochemical kinetics of the sensor is very sensitive to the change of electrode potential. Many experimental results collected above proved that the dissociation of hydrogen peroxide is dependent on the catalytic power of mugwort peroxidase qualitatively and quantitatively at the surface of the mugwort electrode. It is our firm belief that the marketed HRP can be replaced with mugwort tissue.

• New & Renewable Energy
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• v.5 no.2
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• pp.9-14
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• 2009

Automobile Shredder Residue (ASR) is very appropriate in a gasification melting system. Gasification melting system, because of high reaction temperature over than $1,350^{\circ}C$, can reduce harmful materials. To use the gasification processes for hydrogen production, the high concentration of CO in syngas must be converted into hydrogen gas by using water gas shift reaction. In this study, the characteristics of shift reaction of the high temperature catalyst (KATALCO 71-5M) and the low temperature catalyst (KATALCO 83-3X) in the fixed - bed reactor has been determined by using simulation gas which is equal with the syngas composition of gasification melting process. The carbon monoxide composition has been decreased as the WGS reaction temperature has increased. And the occurrence quantity of the hydrogen and the carbon dioxide increased. When using the high temperature catalyst, the carbon monoxide conversion ratio ($1-CO_{out}/CO_{in}$) rose up to 95.8 from 55.6. Compared with average conversion ratio from the identical synthesis gas composition, the low temperature catalyst was better than the high temperature catalyst.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.2
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• pp.71-82
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• 2006

This study was carried out to assess and analyze the overall problems of the facilities in recycling and treating of foodwaste on the basis of the unit operation facilities. It proposes effective alternatives for the high profitable management that can meet the regulation of the facilities. The study is composed of several parts including a collection of academic reports, field studies regarding the facilities operated by local government and the private sector, the analysis on odor samples from compost facilities and processing facilities for animal feed from foodwaste. Twenty facilities were surveyed on the field to find out the existing problems and to compare between facilities. Several facilities didn't meet the governmental regulation on some processes, especially the stages of input, storage, odor control and the qualities of final products under the unit equipment operation. The analysis on the odors from the phases of input, shredding and fermentation of a compost facility and processing facilities for feed, the odors from shredding equipments were higher in concentration than the others. The Major odors from the composting facility contained hydrogen sulfide ($H_2S$), methyl mercaptan ($CH_3{SH}$), Dimethyl sulfide ($(CH_3)_2S$) and Ammonia ($NH_3$) and the major odors from the animal feed facility contained methyl mercaptan ($CH_3{SH}$), Trimethylamine ($(CH_3)_3N$) and Acetaldehyde ($CH_3CHO$).

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.371-388
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• 2023

A stratum with a complex composition and a distributed low-permeability soil layer is difficult to remediate quickly because the soil remediation does not proceed easily. For efficient purification, the permeability should be improved and the soil remediation agent (H₂O₂) should be injected into the contaminated section to make sufficient contact with the TPH (Total petroleum hydrocarbons). This study analyzed a method for crack formation and effective delivery of the soil remediation agent based on pneumatic fracturing, plasma blasting, and vacuum suction (the PPV method) and compared its improvement effect relative to chemical oxidation. A demonstration test confirmed the effective delivery of the soil remediation agent to a site contaminated with TPH. The injection amount and injection time were monitored to calculate the delivery characteristics and the range of influence, and electrical resistivity surveying qualitatively confirmed changes in the underground environment. Permeability tests also evaluated and compared the permeability changes for each method. The amount of soil remediation agent injected was increased by about 4.74 to 7.48 times in the experimental group (PPV method) compared with the control group (chemical oxidation); the PPV method allowed injection rates per unit time (L/min) about 5.00 to 7.54 times quicker than the control method. Electrical resistivity measurements assessed that in the PPV method, the diffusion of H₂O₂2 and other fluids to the surface soil layer reduced the low resistivity change ratio: the horizontal change ratio between the injection well and the extraction well decreased the resistivity by about 1.12 to 2.38 times. Quantitative evaluation of hydraulic conductivity at the end of the test found that the control group had 21.1% of the original hydraulic conductivity and the experimental group retained 81.3% of the initial value, close to the initial permeability coefficient. Calculated radii of influence based on the survey results showed that the results of the PPV method were improved by 220% on average compared with those of the control group.

• Journal of Animal Science and Technology
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• v.48 no.3
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• pp.401-414
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• 2006

Twenty eight Holstein steers 12 months old and weighing about 300kg were andomly allotted into one of four groups being fed ammoniated rice straw(ARS) and substituted 30%, 40% and 50% crushed bamboo chip for ARS to determine the effects of different levels of bamboo chip on performance, digestibility and carcass characteristics. Daily weight gain was reduced as the substitution levels of bamboo chip for ARS as a roughage source increased but there were no differences in daily weight gain between steers fed ARS alone and 30% bamboo chip for ARS. Concentrates intakes were not different between treatments by the substitution levels of bamboo chip for the whole fattening period. Roughage intake tended to increase as the substitution levels of bamboo chip increased. Total feed intake was not affected by the substitution levels of bamboo chip. However, feed efficiency got worse with increasing levels of bamboo chip. Animals fed the roughage substituting 30% bamboo chip for ARS were higher in profit by 13% than animals fed ARS alone as a roughage source. Digestibilities of Dry matter(DDM) and crude fiber(DCF) were highest in animals fed ARS alone as a roughage source. DDM's were lower in higher substitution levels of crushed bamboo chip but there were no differences in DCF among animals fed different levels of bamboo chip as a roughage source. Crude protein digestibility was not affected by ammoniated rice straw or by the different levels of bamboo chip. Dressing percentage and backfat thickness were not affected by ammoniated rice straw or by the levels of bamboo chip but ribeye area was narrowed as the levels of bamboo chip increased. Beef color, fat color, texture, maturity and marbling score were not affected by feeding of ammoniated rice straw or by the levels of bamboo chip. According to these results, it may be concluded that profit can increase when Holstein bulls are castrated and roughage containing ammoniated rice straw plus 30% bamboo chip is offered.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.307-327
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• 2008

Geochemical study on the rocks and minerals of the Gyeongju low and intermediate level waste repository was carried out in order to provide geochemical data for the safety assessment and geochemical modeling. Polarized microscopy, X-ray diffraction method, chemical analysis for the major and trace elements, scanning electron microscopy(SEM), and stable isotope analysis were applied. Fracture zones are locally developed with various degrees of alteration in the study area. The study area is mainly composed of granodiorite and diorite and their relation is gradational in the field. However, they could be easily distinguished by their chemical property. The granodiorite showed higher $SiO_2$ content and lower MgO and $Fe_2O_3$ contents than the diorite. Variation trends of the major elements of the granodiorite and diorite were plotted on the same line according to the increase of $SiO_2$ content suggesting that they were differentiated from the same magma. Spatial distribution of the various elements showed that the diorite region had lower $SiO_2,\;Al_2O_3,\;Na_2O\;and\;K_2O$ contents, and higher CaO, $Fe_2O_3$ contents than the granodiorite region. Especially, because the differences in the CaO and $Na_2O$ distribution were most distinct and their trends were reciprocal, the chemical variation of the plagioclase of the granitic rocks was the main parameter of the chemical variation of the host rocks in the study area. Identified fracture-filling minerals from the drill core were montmorillonite, zeolite minerals, chlorite, illite, calcite and pyrite. Especially pyrite and laumontite, which are known as indicating minerals of hydrothermal alteration, were widely distributed in the study area indicating that the study area was affected by mineralization and/or hydrothermal alteration. Sulfur isotope analysis for the pyrite and oxygen-hydrogen stable isotope analysis for the clay minerals indicated that they were originated from the magma. Therefore, it is considered that the fracture-filling minerals from the study area were affected by the hydrothermal solution as well as the simply water-rock interaction.

• Economic and Environmental Geology
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• v.22 no.1
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• pp.1-16
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• 1989

Electrum-galena-sphalerite mineralization of the Yangpyeong-Weonju Au-Ag area was deposited in three stages of quartz and calcite veins which fill fault breccia zones. Fluid inclusion and stable isotope data show that ore mineralization was deposited at temperatures between $260^{\circ}C$ and $180^{\circ}C$ from fluids with salinities between 8.9 and 2.9 equivalent weight percent NaCl. Evidence of boiling indicates pressures of <50 bars, corresponding to depths of 220 to 550 m, respectively, assuming lithostatic and hydrostatic loads. Au-Ag deposition was likely a result of bolling coupled with cooling. Within stages I and II there is an apparent increase in ${\delta}^{34}S$ values of $H_2S$ with paragenetic time ; early -1.4~2.7‰ to later 6.6-9.2‰. The progressively heavier $H_2S$ values can be generated through isotopic re-equilibration in the ore fluid following removal of $H_2S$ by boiling or precipitation of sulfides. Measured and calculated hydrogen and oxygen isotope values of ore-forming fluids suggest meteoric water dominance, approaching unexchanged meteoric water values. Comparison of these values with those of other Korean Au-Ag deposits reveals a relationship between depth and degree of water-rock interaction. All investigated Korean Jurassic and Cretaceous gold-silver-bearing deposits have fluids which are dominantly evolved, meteoric water, but on1y deeper systems (${\geq}1.25km$) are exclusively gold-rich.