• 상하수도학회지
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• 제38권2호
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• pp.69-81
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• 2024

In this study, an evaluation system that can be used to evaluate the feasibility of developing and supplying hydrothermal energy for the operation of large-scale complex facilities was developed. To this end, this study derived factors to be considered when selecting a location for the use of hydrothermal energy using raw water from multi-purpose dams and regional water supply systems through literature survey and expert interviews. The evaluation indicators derived from this study are divided into four sectors: hydrothermal energy utilization factors, location factors, planning factors, and disaster safety factors, and are composed of 10 mid-level indicators and 34 detailed planning indicators. The relative importance of all factors was derived using the Analytic Hierarchy Process (AHP) technique, and the developed evaluation indicators and relative importance were applied to four multi-purpose dam regions in the country. As a result, it was found that in the development and use of hydrothermal energy utilizing regional raw water supply line the urban planning conditions of the supply site can have a greater impact on the location selection results than the hydrothermal energy development itself. Due to the characteristics of the evaluation indicators developed in this study and their nature as comprehensive indicators, it is believed that the results should be applied to determine the overall adequacy of site selection in the early stages of hydrothermal energy development. In the future, it is believed that it will be necessary to analyze the problems in supplying and operating hydrothermal energy using raw water from multi-purpose dams and regional water resources. Based on the analysis the evaluation system developed in this study is expected to be improved and supplemented.

• 자원환경지질
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• 제25권3호
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• pp.225-232
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• 1992

The hydrothermal alteration is evaluated using multicomponent equilibrium calculations with the program CHILLER for the reactions between hydrothermal water and rhyolite at the temperature of $300^{\circ}C$ and pressure of 500 bars. The chemical-reaction model on the depositional processes of the sericitite confirms that the hydrothermal water-rock interaction(hydrothermal alteration) is the main mechanism of the sericitite formation. The principal change in the aqueous phase during the reaction is the pH increase. Overall trends for the major species are the increase in total molalities of K, Ca, $SiO_2$, Al, Mg, Fe, Na, and sulfide in solid phase with hydrothermal water-rhyolite reaction and the decrease of them in aqeous solution by precipitation of hydrothermal products. Quartz and sericite are the first minerals to form. The sequence of minerals to precipitate following them is chlorite, epidote, pyrite and microcline as water/rock ratio decreases. Although calculated results cannot duplicate the complexities of natural hydrothermal alteration, the calculation provides thermodynamic constraints on the natural process. The calculation results resemble those of experimental studies. Sericitite forms where pH decreases and water/rock ratio increases.

• 자원환경지질
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• 제56권2호
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• pp.185-199
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• 2023

This study aimed to predict the effects of water ecology on the supply of hydrothermal energy to model a housing complex in Eco Delta Smart Village in Busan. Based on the results, engineering measures were recommended to minimize problems due to possible temperature variations on the supply of hydrothermal energy from the river. The current distribution of fish, benthic macroinvertebrates, and phytoplankton in the Pyeonggang Stream was monitored to determine their effects on water ecology. In the research area, five species and three families of fish were observed. The dominant species was Lepomis macrochirus, and the subdominant species was Carassius auratus. Twenty-five species and 21 families of benthic macroinvertebrates were found. The distribution of aquatic insects was poor in this area. The dominant species were Chironomidae sp., Lymnaea auricularia, Appasus japonicus, and Caridina denticulata denticulata in February, May, July, and October. Dominant phytoplankton were Aulacoseira ambigua and Nitzschia palea in February and May. Microcystis sp. was dominant in July and October. The health of the ecology the Pyeonggang Stream was assessed as D (bad) according to the benthic macroinvertebrate index (BMI). Shifts in the location of the discharge point 150 m downstream from intake points and discharge through embedded rock layer after adding equal amounts of stream water as was taken at the beginning were suggested to minimize water temperature variations due to the application of hydrothermal energy. When the scenario (i.e., quantity of water intake and dilution water, 1,600 m³/d and water temp. difference ±5 ℃) was realized, variations in water temperature were assessed at -0.19 ℃ and 0.59 ℃ during cooling and heating, respectively, at a point 10 m downstream. Water temperatures recorded at -0.20 ℃ and 0.68 ℃ during cooling and heating, respectively, at a point 10 m upstream. All stream water temperatures after the application of hydrothermal energy recovered within 24 hours. Future work on the long-term monitoring of ecosystems is suggested, particularly to analyze the influence of the water environment on hydrothermal energy supply operations.

• 지질공학
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• 제27권3호
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• pp.345-351
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• 2017

Acid drainage in civil engineering structures such as tunnels may lead to the deposition of precipitates that clog drainage channels and pipework. In evaluating acid drainage, the Fe content of water and precipitates, indicated by reddish brown coloration of rock surfaces, rivers, and soils, may be an important factor. In this study, acid drainage was evaluated by analyzing the Fe content of reddish brown seepage water that occurred in part of a tunnel. Geological investigations around the tunnel revealed a hydrothermal alteration zone cutting the bedrock, and cropping out in the upper parts of the tunnel. Analysis of drillcore revealed many fracture zones and veins. Inductively coupled plasma spectrophotometric analyses of water, precipitates, and soil samples, collected in the seepage water zone and around the tunnel, were conducted to evaluate acid drainage. The Fe content of seepage water in the tunnel was 0.030-0.333 mg/kg, which is 2-22 times higher than in local groundwater. The Fe content of precipitates in the tunnel was 165,403-301,051 mg/kg, similar to the 206,167-422,964 mg/kg content of drillcore from the hydrothermal alteration zone located above the tunnel. It is concluded that the seepage water is derived from Fe-containing acid drainage flowing in perforated tunnel drainpipes along the fracture zones and veins around the hydrothermal alteration zone.

• 상하수도학회지
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• 제29권1호
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• pp.57-63
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• 2015

Recently, Korea's municipal wastewater treatment plants generated amount of wastewater sludge per day. However, ocean dumping of sewage sludge has been prohibited since 2012 by the London dumping convention and protocol and thus removal or treatment of wastewater sludge from field sites is an important issue on the ground site. The hydrothermal carbonization is one of attractive thermo-chemical method to upgrade sewage sludge to produce solid fuel with benefit method from the use of no chemical catalytic. Hydrothermal carbonization improved that the upgrading fuel properties and increased materials and energy recovery, which is conducted at temperatures ranging from 200 to $350^{\circ}C$ with a reaction time of 30 min. Hydrothermal carbonization increased the heating value though the increase of the carbon and fixed carbon content of solid fuel due to dehydration and decarboxylation reaction. Therefore, after the hydrothermal carbonization, the H/C and O/C ratios decreased because of the chemical conversion. Energy retention efficiency suggest that the optimum temperature of hydrothermal carbonization to produce more energy-rich solid fuel is approximately $200^{\circ}C$.

• 자원환경지질
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• 제48권1호
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• pp.15-24
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• 2015

인도네시아 동부 자바의 남서익부에 위치하는 파찌딴 광화대 금속광화작용은 스카른형 교대광체와 열극을 충진 발달하는 열수 맥상광체로 크게 분류할 수 있다. 스카른 형 교대광체는 올리고신 후기 퇴적암류 중 석회암층을 따라 관계화성암체인 석영반암 주변에 발달한다. 본 광체는 스카른광물과 함께 자철석 및 천금속 황화광물이 수반된다. 열수광체로는 관계화성암체인 석영반암으로 부터의 거리를 기준으로 근지성 함 동-아연 망상광체와 원지성 함 연-아연(-금) 맥상광체가 발달 분포한다. 황화광물의 황 동위원소 값으로부터 계산된 $H_2S$의 황 동위원소 값은 스카른광체의 경우 5.6-7.1‰, 열수광체의 경우 0.9-6.8‰ 이었다. 이는 원지성 열수 맥상 광체의 후기 광화작용으로 진행하면서 파찌딴 열수계 내 $SO_4/H_2S$의 비가 증가하면서 $H_2S$의 황동위원소 값이 감소한 것으로 확인된다. 광화대 내 산소 동위원소 값은 스카른 광체 내 자철석, 9.6과 9.7‰; 스카른 광체 내 석영, 6.3-9.6‰; 스카른 광체 내 방해석, 4.7 and 5.8‰; 열수 망상광체 내 석영, 3.0-7.7‰; 열수 망상광체 내 방해석, 1.2 and 2.0‰; 열수 맥상광체 내 석영, -3.9 - 6.7‰로서, 계산된 ${\delta}^{18}O_{water}$ 값은 근지성 스카른 및 열수 망상광체에서 원지성 열수 맥상광체에 이르면서 감소하는 경향성을 보인다. 열수계 ${\delta}D_{water}$ 값은 광체 유형에 관계없이 -65 to -88‰의 값을 보여준다. 이러한 산소 수소 안정동위원소 값의 경향성은 근지성 스카른 및 열수 망상광체 초기 광화작용을 지배한 마그마 기원의 열수 또는 상대적으로 낮은 water/rock 비 값을 갖는 환경하에서 동위원소 교환반응을 이루어 평형상태에 이른 열수가 풍부한 파찌딴 열수계 내에 광화작용의 진행 및 관계화성암과의 거리에 따라 높은 water/rock 비 값을 갖는 환경하에서 동위원소 교환반응을 이루어 진 열수 또는 동위원소 교환반응이 거의 이루어지지 않은 천수의 유입이 점증하며 광화작용이 진행되었음을 의미 한다.

• 광물과산업
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• 제29권
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• pp.56-66
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• 2016

열수변질대가 폭넓게 분포하고 있는 우리나라에서 자연사면이나 인공사면에서 열수변질대 내에 산출되는 점토맥이 산사태 발생에 중요한 역할을 할 수 있다. 점토맥이 존재하는 지반에 지표수가 침투되면 점토광물의 팽윤성 때문에 국지적으로 간극수압이 급격히 상승할 수 있다. 간극수압의 상승으로 세립의 점토광물이 침식될 수 있다. 침식된 점토광물은 수두가 큰 곳에서 작은 곳으로 유동하면서 동수경사가 작은 부분에서 유속이 느려져 퇴적된다. 점토광물이 퇴적된 곳에서 국지적인 간극수압의 증가로 인한 지하수의 유출이 사면파괴를 일으킬 수 있다. 이에 본고에서는 열수변질 점토맥과 산사태와 관련한 국내외 자료를 소개하고자 한다.

• 대한화학회지
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• 제59권3호
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• pp.238-245
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• 2015

The crystallization and morphology change of amorphous titanias by hydrothermal treatment have been investigated. The amorphous titanias were prepared by pure water hydrolysis of two different precursors, titanium tetraisopropoxide (TTIP) and TTIP modified with acetic acid (HOAc) and characterized prior to hydrothermal treatment. In order to avoid complicate situation, the hydrothermal treatment was performed in a single solvent water with and without strong acids at various temperatures. The effects of strong acid, temperature and time were systematically investigated on the transformation of amorphous titania to crystalline TiO₂ under simple hydrothermal condition. Without strong acid the titanias were transformed into only anatase phase nanoparticle regardless of precursor type, temperature and time herein used (up to 250 ℃ and 48 hours). The treatment temperature and time effected only on the crystalline size, not on the crystal phase et al. However, it was clearly revealed that the strong acids such as HNO₃ and HCl catalyzed the formation of rutile phase depending on temperature. HCl was slightly better than HNO₃ in this catalytic activity. The morphology of rutile TiO₂ formed was also a little affected by the type of acid. The precursor modifier, HOAc slightly reduced the catalytic activity of the strong acids in rutile phase formation.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권5호
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• pp.45-52
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• 2014

Torrefaction and hydrothermal carbonization (HTC) are productive methods to reclaim energy from lignocellulosic biomass. The hydrophobic, homogenized, energy dense and carbon rich solid fuel can be obtain from torrefaction and hydrothermal carbonization. Dead leaves were carbonized in a stainless steel reactor of volume 200 ml with torrefaction ($250-270^{\circ}C$) for 120 minutes and hydrothermal carbonization ($200-250^{\circ}C$) for 30 minutes, with mass yield solid fuel ranging from 57-70% and energy content from 16.81MJ/kg to 22.01 MJ/kg compare to the biomass. The char produced from torrefaction process possess high energy content than hydrothermal carbonization. The highest energy yield of 89.96% was obtained by torrefaction at $250^{\circ}C$. The energy densification ratio fluctuated in between 1.15 to 1.30. On the basis of pore size distribution of the chars, the definition of the International Union of Pure and Applied Chemistry (IUPAC) was used as a classification standard. The pore diameter was ranging within 11.09-19 nm which play important role in water holding capacity in soil. Larger pores can hold water and provide passage for small pores. Therefore, it can be concluded that high pore size char can be obtained my HTC process and high energy content char of 22.01 MJ/Kg with 34.04% increase in energy can be obtain by torrefaction process.

• Ocean and Polar Research
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• 제23권1호
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• pp.11-21
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• 2001

K-Ar ages of the altered rocks from the Barton Peninsula are belows; altered tuffaceous andesite from southwestern part is 42 Ma, altered rocks contacted with quartz vein from southern part are 28 and 33 Ma, and advanced argillic altered andesite from northeastern part are 33 and 35 Ma. Those K-Ar ages are 10 My younger than granitic rocks of the Barton Peninsula. Hydothermal alteration of the Barton Peninsula was originated from mixing of magmatic water from parent magma of granitic rocks with meteoric water. The Al content in the hostrock is relatively constant during hydrothermal alteration, on the contrary the Mg content is in proportion to total alkali. The variation of total alkali and Mg contents in hydrothermal alteration indicates that those elements was washed out during hydrothermal alteration. The sequences of hydrothermal alteration of the Barton Peninsula is chloritization of amphiboles, sericitization of feldspars and kaolitization of sericite.