• 시멘트
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• 통권30호
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• pp.44-50
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• 1969

To manufacture portland cement and sulfuric acid from gypsum has long been established in Europe. As sulfur, more Precisely sulfuric acid, is getting around shortage, it boosts hunt for alternate sources and for new fertilizer process. As the result, all

• The Korean Journal of Ecology
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• 제21권1호
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• pp.65-72
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• 1998

Various effects of simulated acid rain by $HNO_3$ and $H_2SO_4$ with pH 3.2, 4.2 and 5.6 were investigated in Melilotus suaveolens Ledeb, a biennial legume dominating the disturbed and poor soil vegetations. The nitric acid treatment of pH 3.2 resulted in 121% increase of the plant height compared to that of pH 5.6 during early growth, although 17% decrease was detected with the sulfuric acids. During 14 days of treatment, leaf biomass and chlorophyll content increased 168% and 133% with pH 3.2 nitric acid rain but decreased 20% and 38%, respectively, with sulfuric acid rain. Nitrogen content in various organs was also determined after 42 days of nitric acid treatment. It increased 480% and 387% by pH 3.2 and 4.2 in leaves, 212% and 214% in stems and 247% and 249% in roots. However, the same treatment with the sulfuric acid showed a considerable reduction in this content, indicating that the nitric acid was a nitrogen source. Nodule formation assayed revealed 15% decrease with pH 3.2 in contrast to 157% increase in pH 4.2, further suggesting an enhancement effect by the additional nitrogen source. Contrary to this, the nodule formation was reduced up to 43-71% by sulfuric acid rains. Specific nitrogen fixation activities of nodules estimated at pH 3.2, 4.2 and 5.6 nitric acid rain were 36.7, 42.8 and 47.3 ${\mu}mol\;C_2H_4{\cdot}g^{-1}\;fw\;nodule{\cdot}h^{-1}$, while those of sulfuric acid rain exhibited 1 nmol $C_2H_4{\cdot}plant^{-1}{\cdot}h^{-1}$ with pH 3.2, 177 with pH 4.2 and 179 with pH 5.6, yet it increased 2, 115 and 286 respectively corresponding to the three sulfuric acid concentrations. Further implications of the simulated acied rain were also discussed in the study.

• Corrosion Science and Technology
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• 제22권5호
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• pp.351-358
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• 2023

Although many thermal power plants use heat recovery systems, high exhaust gas temperatures are maintained due to corrosion at dew points and ash deposits caused by condensate formation. The dew point of exhaust gas is primarily determined by the concentration of SO₃ and steam, and various experiments and calculation equations have been employed to estimate it. However, these methods are known to be less suitable for exhaust gases with low SO₃ concentrations. Therefore, in this study, since the temperature of the exhaust gas is expected to decrease due to the low-load operation of the coal-fired power plant, sulfuric acid condensation and low-temperature corrosion are anticipated. We aimed to conduct a quantitative evaluation to propose ways to prevent damage by limiting operating conditions and improving facilities. The experimental results showed that the corrosion rate increased linearly with rising temperatures at a certain sulfuric acid concentration. Furthermore, variations in sulfuric acid concentrations generated during the current power plant operation process did not significantly affect the dew point, and the dew point of sulfuric acid under these conditions was observed to be between 120 - 130 ℃.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.664-666
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• 1987

In this study, the computation of optimum operating conditions for catalytic oxidation of sulfur dioxide to sulfur trioxide in CONVERTER which determines the yield ultimately in sulfuric acid plant is performed on an IBM/XT computer. The process simulator of rigorous converter model including mass & energy balance equations and supporting equations is linked to optimizer, which produces the desired results successfully.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.719-722
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• 2004

Resins using recycled PET offer the possibility of a lower source cost of materials for making useful polymer concrete products. The purposed of this paper is to form a part of reducing the damage of sulfuric acid, through investigating recycled PET polymer concrete, . immersed at sulfuric acid solution for 84 days. Recycled PET PC is excellent chemical resistance, resulting in the role of unsaturated polyester resin which consists of polymer chain structure accomplishes bond of aggregates and filler strongly. Also, Recycled PET PC, used fly-ash as filler, is stronger resistance of sulfuric acid corrosion than $CaCO_3$, because it is composed of $SiO_2$ and very strong glassy crystal structure. Therefore, Recycled PET PC, used fly-ash as filler, is available under corrosion circumstances like sewer pipe or waste disposal plant.

• 한국표면공학회지
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• 제55권6호
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• pp.433-440
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• 2022

Environmental pollution caused by power plant exhaust gas is highlighted and eco-friendly regulations are being strengthened. However, due to the abundant reserves and low prices of coal, still the most used for power generation in the world. Therefore, flexible operation of coal-fired power plants to reduce emissions has become an inevitable option. However, lowering the output increases the possibility of acid dew point corrosion as the exhaust gas temperature decreases. The dew point corrosion occurs when condensable gases such as SO₃, HCl, NO₂ and H₂O cools below the saturation temperature. SO₃ is already well known to cause severe low- temperature corrosion in coal-fired power plants. Therefore, this study aims to prevent damage that may occur during operation by analyzing the dew point and corrosion resistance with exhaust gas temperature and sulfuric acid concentration of the power plant economizer tube.

• Nuclear Engineering and Technology
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• 제41권6호
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• pp.831-840
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• 2009

In order to evaluate the start-up behavior and to identify, through abnormal operation occurrences, the transient behaviors of the Sulfur Iodine(SI) process, which is a nuclear hydrogen process that is coupled to a Very High Temperature Gas Cooled Reactor (VHTR) through an Intermediate Heat Exchanger (IHX), a dynamic simulation of the process is necessary. Perturbation of the flow rate or temperature in the inlet streams may result in various transient states. An understanding of the dynamic behavior due to these factors is able to support the conceptual design of the secondary helium loop system associated with a hydrogen production plant. Based on the mass and energy balance sheets of an electrodialysis-embedded SI process equivalent to a 200 $MW_{th}$ VHTR and a considerable thermal pathway between the SI process and the VHTR system, a dynamic simulation of the SI process was carried out for a sulfuric acid decomposition process (Second Section) that is composed of a sulfuric acid vaporizer, a sulfuric acid decomposer, and a sulfur trioxide decomposer. The dynamic behaviors of these integrated reactors according to several anticipated scenarios are evaluated and the dominant and mild factors are observed. As for the results of the simulation, all the reactors in the sulfuric acid decomposition process approach a steady state at the same time. Temperature control of the inlet helium is strictly required rather than the flow rate control of the inlet helium to keep the steady state condition in the Second Section. On the other hand, it was revealed that the changes of the inlet helium operation conditions make a great impact on the performances of $SO_3$ and $H_2SO_4$ decomposers, but no effect on the performance of the $H_2SO_4$ vaporizer.

• 생약학회지
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• 제42권1호
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• pp.82-88
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• 2011

This study was carried out to investigate the optimum conditions for extraction of soluble acidic polysaccharides from ginseng marc. Method of carbazole-sulfuric acid was applied to determine the amount of acidic polysaccharides in ginseng marc. The amounts of soluble acidic polysaccharides in water extract of ginseng marc were increased with increasing extraction temperature. The contents of acidic polysaccharides were not significantly different despite the extraction time increasing from 0.5 hours to 6 hours. To estimate the rehydration rate of the freeze dried polysaccharide, the extracted acidic polysaccharide fraction powder was determined the amount of soluble acidic polysaccharides by carbazole-sulfuric acid method again. The rehydration rate of acidic polysaccharides from water-extract of red ginseng marc at room temperature was 100%. On the other hand, the rehydration rate of acidic polysaccharide of red ginseng marc at boiling temperature was about 50%. The rehydration rate of acidic polysaccharides from water-extract of white ginseng marc at room temperature was 50%. The rehydration rate of acidic polysaccharide of red ginseng marc at boiling temperature was about 40%. The rate of soluble acidic polysaccharide of Red Ginseng is higher than that of White Ginseng. We can find out the maximum extraction method of soluble acidic polysaccharide from ginseng marc.

• 한국자원식물학회지
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• 제13권1호
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• pp.48-53
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• 2000

옻나무 묘목대량증식법의 하나로 조직배양 방법을 이용하여 기내 유식물체를 다량으로 증식함으로써 옻나무 증식의 효율성을 높이기 위하여 기내 무균묘를 얻고자 실시하였다. 비중 1.0으로 선종한 결과 1차선종은 평균 50.7%의 선종율을 보였고, 98% sulfuric acid에 2시간 교반 후 2차로 선종한 결과 선종율은 20.8%였다. 발근율은 외종피를 함유한 종자(5.4%) 보다는 외종피를 제거하거나(18.3%) 내종피를 제거한 종자(32.4%)가 높았다. 전처리에 따른 종자의 발아율은 생장조절물질 처리에 의한 효과가 인정되지 않았으며, 각 처리별 유의수준도 인정되지 않았으나 sulfuric acid를 처리했을 경우 발아율이 3%로써 생장조절물질 처리보다는 약간 효과적인 것으로 나타났다. 외종피를 제거하면 발아율은 약간 높게 나타났는데, 생장조절물질을 첨가함으로써 약 4%정도 향상되었다. 특히 BA 1.0mg/L와 NAA 0.05mg/L의 혼용처리와 BA 1.0mg/L 단독처리가 10% 내외의 발아율을 보였다. 옻나무 종자는 배지에 치상한 후 약 10일 만에 정상적으로 발아하였고, 치상 후 약 3주만에 본엽이 출현한 정상적인 무균묘를 획득할 수 있었으나 발아율이 10%내외에 불과하여 매우 저조하였다.

• 한국가스학회지
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• 제3권2호
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• pp.70-76
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• 1999

이산화황 배출에 대한 대기 오염 방지법의 엄격한 규제로 인하여 황산제조 업체에서는 가능한 높은 전화율을 얻는 방법에 관심을 갖고 있다. 본 연구에서는 현재 가동하고 있는 황산공장의 이중 접촉식 전환탑 공정에서 전화율을 증가시키고 배출되는 이산화황 가스의 농도를 최소화하기 위하여 매개변수 분석과 공정최적화 방법을 사용하였다. 이중 접촉식 전환탑 공정에 대하여 공급되는 이산화황의 조성, 각 촉매층 도입부의 압력과 온도, 촉매층의 높이의 변화에 대한 전화율 변화를 살펴보기 위해 공정 모델링과 컴퓨터 모사 프로그램을 개발하였다. 이를 통해 삼산화황으로의 최대 전화율과 배출되는 잔여 이산화황 가스 농도의 최소를 위해 촉매층의 도입부의 온도와 촉매층 높이를 최적화하였다. 이 최적치는 높은 전화율을 유지하도록 하는 전환탑 설계와 조업 조건의 지침이 될 것이다.