순산소 Jet 폭기 시스템을 이용한 음폐수 처리 특성

윤애화,박노백,배종훈,권영배,전항배 대한상하수도학회 2010 상하수도학회지 Vol.24 No.6

The removal efficiencies and a total oxygen transfer coefficient for food waste leachate(FWL) were estimated by using Jet Loop Reactor(JLR). Pure oxygen was used instead of air to improve oxygen concentration in the JLR for high total chemical oxygen demamd(TCOD) in FWL. In JLB, in order to examining the oxygen transfer characteristic, the circulation flowrate and oxygen flowrate were controlled with 7~10 L/min(1.5 L/min interval) and 0.2~0.5 L/min (0.1 L/min interval) and we experimented according to the each condition. As a result, Oxygen uptake rate(OUR) and oxygen transfer rate could be maximized than the oxygen flowrate to increase the circulation flowrate. In addition, it determined that JLR using the pure oxygen which can obtain the greatest oxygen transfer rate as it was the high-concentration organic wastewater like the food waste leachate through the continuous experiment was appropriate.

Advanced Treatment of Food Waste Leachate Using the Aeration Reactor with High Efficiency Pure Oxygen

이상혁,고재춘 한국도시환경학회 2010 한국도시환경학회지 Vol.10 No.2

Using aeration reactor of high efficiency pure oxygen to remove the high concentration wastewater generated by the solution separated from food waste, the results got from a pilot test are summarized as follows. 1. The process composition to remove the high concentrated organic matter and the nitrogen of wastewater is the facilities to control the primary high liquid separation and the second biological control process is composed of the anoxic tank and the high pure oxygen aeration reactor and the separation membrane tank, and the advanced control is composed of the ozone and activated carbon treatment facility. 2. As the average concentration of 200,000 mg/L is separated into high liquid to mix with excess sludge, the water separated from high liquid is able to get the average of 32,000 mg/L, and when the load of about 20 kgCODCr/m3·d removes by the reactor of the pure oxygen aeration with high efficiency, it has been removed over the 98.7% to an outflow with average 422 mg/L. 3. As the BOD flows into the raw wastewater with 90,000 mg/L, an average concentration shows 32,000 mg/L after a primary high liquid separation and is able to get the effluent water under below 10 mg/L to remove 99.9% by the aeration reactor of high efficiency pure oxygen. 4. T-N represents average 1,520 mg/L when the raw wastewater with about 3,500 mg/L is separated from high liquid, and it is removed to the efficiency of 94.1% or more when it is controlled to inflow in the aeration reactor of high efficiency pure oxygen. 5. The T-P concentration of the separated liquid is average 723 mg/L and approximately 75% are removed by high liquid separation after a primary dewatering.

Global and local strain rate sensitivity of commercially pure titanium

Lee, Min-Su,Hyun, Yong-Taek,Jun, Tea-Sung Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.803 No.-

<P><B>Abstract</B></P> <P>We have performed macroscopic tensile and nanoindentation tests to investigate the effect of oxygen content on the global and local strain rate sensitivity of grades 1, 2 and 4 commercially pure titanium (CP–Ti). Electron backscatter diffraction (EBSD) was used to characterise the crystallographic texture of target samples and orientation of target grains. Slip activities were anticipated by Schmid factor analysis, indicating the relative incidence of <a> type prismatic and basal slips in the macroscopic region, and similarity of potential local deformation between comparative grain orientations. Further slip trace analysis around the residual impressions showed similar slip activity in equivalent orientations regardless of oxygen content. Global and local strain rate sensitivity were evaluated with respect to the influence of texture and grain orientations, respectively. Significant oxygen-dependent rate sensitivity is observed such that the rate sensitivity is inverse to the oxygen content and this effect is agreed on at both macro- and microscopic levels. These findings are potentially important for understanding the influence of oxygen content on the dwell fatigue of Ti alloys and correlating the intrinsic mechanism at the microscopic level to the macroscopic deformation behaviours.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Macroscopic tensile CSR and nanoindentation jump test were performed on CP-Ti. </LI> <LI> Global texture and target grain orientation was characterised by EBSD measurement. </LI> <LI> Slip activities on textures and grain orientations were anticipated by Schmid law. </LI> <LI> Texture and grain orientation dependent rate sensitivity are observed in CP-Ti. </LI> <LI> Rate sensitivity was decreased with an increase of oxygen solutes in multi-scale. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

순산소 연소용 축열시스템 내에서의 열 유동 수치해석

강관구(K. Kang),홍성국(S.K. Hong),노동순(D.S. Noh),유홍선(H.S. Ryou) 한국전산유체공학회 2013 한국전산유체공학회지 Vol.18 No.3

A pure oxygen combustion technology is crucial in Carbon Capture and Storage (CCS) technology especially in capturing of CO₂, where CCS will reduce 9 GtCO₂ by 2050, which is 19% of the total CO₂ reduction amount. To make pure oxygen combustion feasible, a regenerative system is required to enhance the efficiency of pure oxygen combustion system. However, an existing air combustion technology is not directly applicable due to the absence of nitrogen that occupies the 78% of air. This study, therefore, investigates the heat and fluid flow in a regenerative system for pure oxygen combustion by using commercial CFD software, FLUENT. Our regenerative system is composed of aluminium packed spheres. The effect of the amount of packed spheres in regenerator and the effect of presence or absence of a bypass of exhaust gas are investigated. The more thermal mass in regenerator makes the steady-state time longer and temperature variation between heating and regenerating cycle smaller. In the case of absence of bypass, the regenerator saturates because of enthalpy imbalance between exhaust gas and oxygen. We find that 40% of exhaust gas is to be bypassed to prevent the saturation of regenerator.

순산소와 Vortex Aerator를 이용한 도심하천의 수질 및 악취 관리

윤다인(Yoon, Dain),최미정(Choi, Mijeong),박성혁(Park, Sunghyuk) 대한토목학회 2021 대한토목학회논문집 Vol.41 No.5

와류에 의해 물과 산소의 충돌을 반복적으로 일으켜 산소를 용존시키는 Multistage Vortex Aerator를 하천 정화에 적용하였다. 본 연구의 대상 현장인 괴정천은 부산시 사하구 도심을 흘러 낙동강 하구로 연결되는데, 우천 시에는 비점 오염물질이 유입되고 평시에도 하수 슬러지가 일부 유입되어 퇴적을 반복함에 따라 하천수의 용존산소 농도가 혐기성 상태에 가까웠다. 산소농도가 최소 0.1 ppm인 하천수를 흡입하여 22 ppm 이상으로 산소를 용존시켜 분당 1 m³을 순환시켰을 때, 하천에 나타나는 수질과 악취 변화를 2개월간 모니터링하였다. 운영 결과, 용존산소가 하천 전체적으로 약간 나쁨(4)~나쁨(5)에서, 좋음(1b)~보통(3) 등급으로 개선되었고, 총인 농도는 평균 76 % 감소되었다. 복합악취는, 하천 전체가 혐기화된 측정일에 최대 84.5 % 저감을 관찰할 수 있었다. The target site, Goejeongcheon flows through downtown of Saha-gu, Busan and it connects to the Nakdong-gang estuary. But non-point pollutants and sewage sludge are partially flowing into the stream and deposited. As a result, dissolved oxygen concentrations of the stream were observed close to the anaerobic condition. Multistage Vortex Aerator was applied for restoring this urban stream. It dissolves oxygen by repeatedly causing collisions between water and oxygen by vortex flow. The changes in water quality and odor were monitored for 2 months while circulating 1 ㎥/min of water with 22 ppm dissolved oxygen. As a result of the operation, the dissolved oxygen was improved from slightly Bad (4)~Bad (5) to Good (1b)~Normal (3) grade, and the total phosphorus concentration was decreased by 76 % on average. In the case of complex odor, a maximum reduction of 84.5 % was observed on the day the entire river was anaerobic. Through this study, we evaluated the feasibility of applying pure oxygen and Vortex Aerator for the the stream restoration. It is expected that the results of this study can be used for full-scale design.

음료 농축액 및 퓨레의 항산화 활성

김단비(Dan Bi Kim),신기해(Gi Hae Shin),조주현(Ju Hyun Cho),백순옥(Soon Ok Baik),이옥환(Ok-Hawn Lee) 한국식품영양과학회 2013 한국식품영양과학회지 Vol.42 No.7

본 연구에서는 음료 농축액 및 퓨레로 사용되는 석류 농축액, 블루베리 농축액, 양파추출 농축액, 도라지추출 농축액, 흑마늘 농축액, 홍삼 농축액, 아사이베리 퓨레, 새싹유채 퓨레의 이화학적 특성, 총 페놀 함량, 항산화 효능(DPPH radical scavenging, ORAC) 및 아질산염 소거능을 분석하였다. pH는 석류 농축액이 2.81로 가장 낮았으며 양파추출 농축액이 5.12로 가장 높은 수치를 나타냈다. Brix는 홍삼 농축액이 70.30으로 가장 높았고 새싹유채 퓨레가 1.70으로 가장 낮았다. 총 페놀 함량은 아사이베리 퓨레에서 182.71 mg GAE/mL로 다른 시료에 비하여 높은 수치를 나타냈고 양파추출 농축액이 8.80 mg GAE/mL로 가장 낮았다. DPPH 라디칼 소거능 측정은 총 페놀 함량과 마찬가지로 아사이베리 퓨레에서 69.88%로 가장 높은 활성을 나타내었다. ORAC 지수는 블루베리 농축액에서 27,514 μMTE/mL로 가장 높게 나타났으며 아질산염 소거능도 아사이베리 퓨레에서 28.19%로 유의적으로 높은 활성을 보였다. 이상의 연구 결과로부터 천연물 유래 농축액 및 퓨레는 다양한 항산화 평가모델에서 항산화 활성을 나타내었으며 이들 농축액 및 퓨레를 이용한 항산화 활성을 갖는 건강음료의 원료로서 활용이 가능할 것으로 사료된다. This study investigated the physicochemical properties (pH, Brix), total phenol content, antioxidant activities (DPPH radical scavenging activity and oxygen radical absorbance capacity (ORAC)), and nitrite scavenging activity of beverage concentrates and purees. All concentrates and purees were produced from natural materials and have been used as the main ingredients in health-related beverages. Our results show that the pH values and Brix of all concentrates and purees ranged from 2.81 to 5.12 and 1.70 to 70.30 Brix, respectively. The highest total phenol content (182.71 mg GAE/mL), DPPH radical scavenging activity (69.88%) and nitrite scavenging activity (28.19%) were obtained from acai berry puree. The concentrate from wild blueberry had the highest ORAC value (27,514 μM TE/mL). Among the correlation coefficient data, the total phenol content exhibited a high correlation coefficient (r=0.9099) and DPPH radical scavenging activity. These results suggest that concentrates and purees from natural materials contribute to antioxidant activities in healthy beverages.

Variation of work hardening rate by oxygen contents in pure titanium alloy

Kang, D.s.,Lee, K.j.,Kwon, E.p.,Tsuchiyama, T.,Takaki, S. Elsevier Sequoia 2015 Materials science & engineering. properties, micro Vol.632 No.-

Pure titanium-oxygen alloys with different oxygen contents were tensile-tested to investigate the effect of oxygen on work hardening rate and deformation behavior. Yield and ultimate tensile strengths markedly increased with increasing oxygen contents, although the elongations were decreased. Work hardening rate was also enhanced with increasing oxygen contents resulting in increase in the uniform elongation. The improved work hardening rate was ascribed to transition of primary deformation mode from twin deformation to dislocation slip by oxygen addition. When twin deformation is suppressed by oxygen addition, however, the <c+a> dislocation must function as a substitute for twinning to permit the homogeneous plastic deformation. It contributed that the improved work hardening rate without deformation twinning is thought to be a restriction of dislocation slips to a certain special plane by oxygen addition.

A Comparative Analysis of Two Different Wastewater Treatment Processes in Actual Wastewater Treatment Plants

Hun-Kyun Bae 계명대학교 자연과학연구소 2018 Quantitative Bio-Science Vol.37 No.1

In this study, two different wastewater treatment systems, a conventional activated sludge process and pure oxygen activated sludge process, used at a municipal wastewater treatment facility in California were investigated. Their BOD and NH₃ removal efficiencies, sludge productions, and economic efficiencies were compared. The BOD removal efficiency of the conventional activated sludge process (92.4~95.4%) is similar to that of the pure oxygen activated sludge process (91.9~96.2%). Further, both processes showed poor NH₃ removal efficiencies; 9~18% for the conventional activated sludge process and 0~11.1% for the pure oxygen activated sludge process. Such poor NH₃ removal efficiencies are probably because these processes are optimized for BOD removal. The pure oxygen activated sludge process produced 2~3 times more sludge than the conventional activated sludge process. The pure oxygen activated sludge process was slightly more economically efficient than the conventional activated sludge process (saved about 0.3 million $/yr).

A Comparative Analysis of Two Different Wastewater Treatment Processes in Actual Wastewater Treatment Plants

배헌균 계명대학교 자연과학연구소 2018 Quantitative Bio-Science Vol.37 No.1

In this study, two different wastewater treatment systems, a conventional activated sludge process and pure oxygen activated sludge process, used at a municipal wastewater treatment facility in California were investigated. Their BOD and NH3 removal efficiencies, sludge productions, and economic efficiencies were compared. The BOD removal efficiency of the conventional activated sludge process (92.4~95.4%) is similar to that of the pure oxygen activated sludge process (91.9~96.2%). Further, both processes showed poor NH3 removal efficiencies; 9~18% for the conventional activated sludge process and 0~11.1% for the pure oxygen activated sludge process. Such poor NH3 removal efficiencies are probably because these processes are optimized for BOD removal. The pure oxygen activated sludge process produced 2~3 times more sludge than the conventional activated sludge process. The pure oxygen activated sludge process was slightly more economically efficient than the conventional activated sludge process (saved about 0.3 million $/yr).

압력 및 용존산소량이 증류수 과냉각 해소에 미치는 영향

박세창(SeChang Park),정수진(Su-Jin Jeong),박천완(ChunWan Park),이동규(DongGyu Lee),강채동(Chaedong Kang) 대한설비공학회 2013 대한설비공학회 학술발표대회논문집 Vol.2013 No.6

It is proposed that the dissolved air in pure water has been related to the release of supercooling. In this study, a supercooling experiment is performed to test tubes of pure water with three fixed initial dissolved oxygen(DO=4.1, 7.5, and 12.6 mg/L), i.e. dissolved air. The initial DO in each test tube is maintained to constant during supercooling, as possible. And the pressure effect on supercooling release of pure water is observed to supercooling degree and visualization of bubbles enclosed to the ice after full crystallization of the pure water. At results, the distribution and maximum of supercooling degree in each initial DO relate to the initial DO in pure water. Moreover, the supercooling degree of pure water relates to the pressure of the pure water. And the distribution of bubble in ice proves the effect of the initial DO and the pressure of supercooled water.