• 제목/요약/키워드: Cathodic control

검색결과 78건 처리시간 0.031초

해양환경 중 음극전류 프로세스에 의해 강판에 형성된 석회질 피막의 특성 분석 (The Characteristic Analysis of Calcareous Deposit Films Formed on Steel Plate by Cathodic Current Process in Marine Environment)

  • 박준무;강재욱;최인혜;이승효;문경만;이명훈
    • 한국표면공학회지
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    • 제49권2호
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    • pp.166-171
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    • 2016
  • Cathodic protection is widely recognized as the most cost effective and technically appropriate corrosion prevention methodology for the port, offshore structures, ships. When applying the cathodic protection method to metal facilities in seawater, on the surface of the metal facilities a compound of calcium carbonate($CaCO_3$) or magnesium hydroxide($Mg(OH)_2$) films are formed by $Ca^{2+}$ and $Mg^{2+}$ ions among the many ionic components dissolving in the seawater. And calcareous deposit films such as $CaCO_3$ and $Mg(OH)_2$ etc. are formed by the surface of the steel product. These calcareous deposit film functions as a barrier against the corrosive environment, leading to a decrease in current demand. On the other hand, the general calcareous deposit film is a compound like ceramics. Therefore, there may be some problems such as weaker adhesive power and the longer time of film formation uniting with the base metal. In this study, we tried to determine and control the optimal condition through applying the principle of cathodic current process to form calcareous deposit film of uniform and compact on steel plate. The quantity of precipitates was analyzed, and both the morphology, component and crystal structure were analyzed as well through SEM, EDS and XRD. And based on the previous analysis, it was elucidated mechanism of calcareous deposit film formed in the sacrificial anode type (Al, Zn) and current density (1, 3, $5A/m^2$) conditions. In addition, the taping test was performed to evaluate the adhesion.

콘크리트 중의 철근부식 방지를 위한 외부전원법의 적용 (The Application of Impressed Current System for the Corrosion Control of Reinforcing Steel in Concrete)

  • 문한영;김성수;김홍삼
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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    • pp.197-202
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    • 1997
  • Recently the interest in the reinforcing steel corrosion due to the use of sea-sand and deicing salt, marine environment, and carbonation in RC structures is increasing, therefore the studies on the corrosion control of reinforcing steel in concrete are vigorously proceeding. In this study, from the viewpoint of electrochemical process of steel corrosion in concrete we applied the impressed current system among the cathodic protections to reinforcing steel in concrete and ascertained the protection effect by half-cell potential, corrosion rate, and depolarization.

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Application of Cathodic Protection on Metallic Structure in Extremely Acidic Fluids

  • Chang, H.Y.;Yoo, Y.R.;Jin, T.E.;Kim, Y.S.
    • Corrosion Science and Technology
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    • 제4권4호
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    • pp.140-146
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    • 2005
  • Fossil fired power plant produces the electric energy by using a thermal energy by the combustion of fossil fuels as like oil, gas and coal. The exhausted flue gas by the combustion of oil etc. contains usually many contaminated species, and especially sulfur-content has been controlled strictly and then FGD (Flue Gas Desulfurization) facility should be installed in every fossil fired power plant. To minimize the content of contaminations in final exhaust gas, high corrosive environment including sulfuric acid (it was formed during the process which $SO_2$ gas combined with $Mg(OH)_2$ solution) can be formed in cooling zone of FGD facility and severe corrosion damage is reported in this zone. These conditions are formed when duct materials are immersed in fluid that flows on the duct floors or when exhausted gas is condensed into thin layered medium and contacts with materials of the duct walls and roofs. These environments make troublesome corrosion and air pollution problems that are occurred from the leakage of those ducts. The frequent shut down and repairing works of the FGD systems also demand costs and low efficiencies of those facilities. In general, high corrosion resistant materials have been used to solve this problem. However, corrosion problems have severely occurred in a cooling zone even though high corrosion resistant materials were used. In this work, a new technology has been proposed to solve the corrosion problem in the cooling zone of FGD facility. This electrochemical protection system contains cathodic protection method and protection by coating film, and remote monitoring-control system.

콘크리트 중의 철근 부식 억제를 위한 외부전원법의 효과 (Effect of Impressed Current System for Corrosion Protection of Rebars in Concrete)

  • 문한영;김성수;김홍삼
    • 콘크리트학회지
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    • 제11권2호
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    • pp.221-230
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    • 1999
  • 콘크리트 구조물에 균열이 생겨 물과 산소의 침투확산이 용이해 지거나 또는 외부로부터 염소이온과 같은 염화물이 침투확산되어 콘크리트 중의 철근까지 도달할 경우 및 콘크리트의 중성화가 철근위치까지 진행될 경우 철근의 부동태 피막은 파괴되어 부식이 급진전 되며 콘크리트의 박리 및 탈락현상이 수반될 뿐만 아니라 구조물의 내구성이 크게 저하된다. 본 연구에서는 콘크리트 중의 철근부식을 억제하기 위한 한 방안으로 적용되는 전기방식의 이론적인 고찰과 콘크리트 내부에 다량의 염화물을 함유시키거나 또는 균열을 발생시킨 시험체에 대하여 외부전원법을 활용한 실내실험을 실시하여 철근의 방식효과에 대해 고찰하였다. 외부전원법에 의한 전기방식을 실시하여 복극량을 측정한 결과 대상 시험체 모두 NACE의 방식기준을 만족하였으며, 부식면적율의 측정결과 34 ~84%, 단면감소의 경우 84 ~ 86%의 방식효과를 확인하였다.

아연 메쉬 희생양극을 이용한 콘크리트 파일의 음극방식 특성 및 방식전류 유효거리 (Cathodic Protection Characteristics and Effective Length of Protection Current of Concrete Pile using Zn-mesh Sacrificial Anode)

  • 김기준;정진아;이우철
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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    • pp.773-776
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    • 2008
  • 해양환경에서 철근 콘크리트의 부식은 매우 심하며, 염해는 콘크리트 교량과 항만 구조물의 부식을 일으키는 주요 요인 중 하나이다. 특히 비말대 및 간만대의 수면 부분은 구조물의 안전과 수명의 관점에서 볼 때 매우 중요하다. 지난 수십 년간 토목, 건축분야에서 콘크리트구조물 부식을 억제하기 위한 방식법 중 음극방식(cathodic protection, CP)은 많은 발전을 이룩하였으며 이제 보편화되는 추세에 있다. 최근 해양환경에서 콘크리트구조물의 음극방식을 위해 아연 메쉬 희생양극법이 개발 소개되었으나 아직까지도 이에 대한 구체적 내용이 잘 알려지지 않은 상태이다. 따라서 본 연구에서는 아연 메쉬 음극방식이 환경인자에 따라 콘크리트교각에 어떤 영향을 미치는지에 대하여 조사하였다. 아연 메쉬와 철근의 거리에 따라 음극방식 효과를 측정하기 위하여 약 100cm의 파일 시험편에 10cm 세그먼트 철근 8개를 설치하였으며, 아연 메쉬 희생양극에 의한 음극방식의 설계에 관련된 정보를 얻고자 파일 시험편의 높이에 따른 음극방식 전위의 변화와 전류의 감소치를 측정하였다.

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Cathodic Recirculation System Using a Dual-ejector to Improve Oxygen Utilization of a Submarine Fuel Cell

  • Kim, Min-Jin;Sohn, Young-Jun;Lee, Won-Yong
    • 전기화학회지
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    • 제13권3호
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    • pp.193-197
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    • 2010
  • In terms of the system efficiency, it is very useful to apply the ejector into the fuel recirculation system of a fuel cell system since the ejector needs no parasitic power to operate. Since the conventional automotive fuel cell use hydrogen and air as their fuel, the only hydrogen is needed to be recirculated for the better fuel efficiency. On the other hand, the submarine fuel cell needs both hydrogen and oxygen recirculation systems because the submarine drives under the sea. In particular, the cathodic recirculation has to meet the tougher target since the oxygen based pressurized stack generally used in the submarine applications generates the significant amount of the water in the stack during the operation. Namely, the oxygen utilization has designed less than 50% in the whole operating range for the better exhausting of the generated waters. And thereby in terms of the oxygen utilization, the entrainment ratio of the ejector should be more than 1 within the whole operating range. However, the conventional ejector using a constant nozzle can not afford to satisfy the mentioned critical requirement. To overcome the problem, the dual-ejector and its control strategy are designed. The performance of the proposed dual-ejector is verified by the experiments based on the real operating conditions of the target submarine system. Furthermore, the proposed design method can be used for the other fuel recirculation system of a large-scale fuel cell system with the critical requirement of the fuel utilization.

딥러닝을 활용한 도시가스배관의 전기방식(Cathodic Protection) 정류기 제어에 관한 연구 (A Study on Cathodic Protection Rectifier Control of City Gas Pipes using Deep Learning)

  • 이형민;임근택;조규선
    • 한국가스학회지
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    • 제27권2호
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    • pp.49-56
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    • 2023
  • 4차 산업혁명으로 인공지능(AI, Artificial Intelligence) 관련 기술이 고도로 성장함에 따라 여러 분야에서 AI를 접목하는 사례가 증가하고 있다. 주요 원인은 정보통신기술이 발달됨에 따라 기하급수적으로 증가하는 데이터를 사람이 직접 처리·분석하는데 현실적인 한계가 있고, 새로운 기술을 적용하여 휴먼 에러에 대한 리스크도 감소시킬 수 있기 때문이다. 이번 연구에서는 '원격 전위 측정용터미널(T/B, Test Box)'로부터 수신된 데이터와 해당시점의 '원격 정류기' 출력을 수집 후, AI가 학습하도록 하였다. AI의 학습 데이터는 최초 수집된 데이터의 회기분석을 통한 데이터 전처리로 확보하였고, 학습모델은 심층 강화학습(DRL, Deep Reinforce-ment Learning) 알고리즘 중(中) Value기반의 Q-Learning모델이 적용하였다. 데이터 학습이 완료된 AI는 실제 도시가스 공급지역에 투입하여, 수신된 원격T/B 데이터를 기반으로 AI가 적절하게 대응하는지 검증하고, 이를 통해 향후 AI가 전기방식 관리에 적합한 수단으로 활용될 수 있는지 검증하고자 한다.

에폭시도막 강구조물의 부식특성에 관한 연구 (Study on the Characteristics of Corrosion for Epoxy Coated Steel Structure)

  • 임우조;천정현;정기철
    • 수산해양기술연구
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    • 제34권2호
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    • pp.223-230
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    • 1998
  • Recently, with the rapid development in the industries such as mechanical plants, automobiles, ships and marine structures, it is enlarged by the use of the SS 41 steel. This mechanical plants and marine structures are exposed m corrosion because of Cl-under marine environments. To protect their accidents, mainly applied anti-corrosion epoxy coating and various protective its structures. In this study, corrosion control characteristics on the epoxy coating were investigated by the galvanic corrosion of impressed voltage tester under marine environments The main results obtained are as follows; 1. Corrosion current density of amine-epoxy coating becomes more increased than that of other epoxy coating and the time area rate of pin hole and pit until 5% becomes most rapid. 2. The potential of SUS 304 stainless steel(cathode) for Al-epoxy coating is nearly zero potential. 3. Corrosion current density of Amine-epoxy by shot blast becomes more decreased than that of not shot blast and cathodic potential becomes more noble. 4. As distance of anode and cathode is more decreased, corrosion current density of epoxy coating is more increased and cathodic potential becomes less noble.

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Corrosion in Oil well Stimulation Processes Caused by Different Chelating Agents Based on EDTA Compounds

  • Calderon, J.A.;Vasquez, F.A.;Arbelaez, L.;Carreno, J.A.
    • Corrosion Science and Technology
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    • 제16권2호
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    • pp.59-63
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    • 2017
  • Chelating solutions can be damaged by strong acids during oil production. To design effective corrosion inhibitors and other alternatives for corrosion control, it is important to understand not only the behavior of the system under operating condition but also the kinetics of electrochemical reactions during the corrosion process. In this study, the electrochemical behaviors of P-110 steel in aqueous fluids based on ethylenediaminetetraacetic acid (EDTA) compounds under various temperatures and hydrodynamic regime conditions were assessed. Electrochemical measurements were conducted using rotating disc electrodes manufactured. Electrolytes were prepared using aqueous compounds of EDTA like diammonium salt, disodium salt, and tetrasodium salt. Potentiodynamic polarization, electrochemical impedance, and mass loss tests were performed in order to assess the corrosion kinetic in electrolytes. Hydrodynamic effects were observed only in the cathodic polarization curve. This proves that hydrodynamic regime plays an important role in the corrosion of steel mainly in disodium and diammonium EDTA solutions. Two cathodic reactions controlled the corrosion process. However, oxygen level and pH of the electrolyte played the most important role in metal corrosion. Corrosion rates in those fluids were decreased drastically when oxygen concentration was reduced.

희생양극법을 이용한 콘크리트중의 철근부식 억제 효과에 대한 연구 (A Study on the Rebar Corrosion Control in Concrete by Using the Sacrificial Anode Cathodic Protection)

  • 문한영;김성수;김홍삼;김성섬
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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    • pp.299-302
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    • 1997
  • Generally the corrosion expansion of the steel due to outdoor corrosive environmental factor brings about serious problem on the durability of concrete structures. It is the purpose of this study to see whether adapted sacrificial anode method is effective or not. from the experimental results. the potential of steel in concrete in case of adapting the sacrificial anode method satisfies protection standard value (less than -850mV vs CSE).

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