고정층과 순환유동층에서 CaSO_4의 환원반응에 대한 온도와 CO농도의 영향

배달희,류호정,박재현,이창근,선도원,이동규 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.1

순환유동층 석탄연소로에서 석회석에 의한 찰황반응에 영향을 미치는 CaSO_4의 환원반응에 의한 SO-2 재배출을 실험적으로 확인하고 SO_2의 재배출에 미치는 온도와 CO 농도의 영향에대해 상용 순환유동층에 적용할 수 있는 기초자료를 확보하기 위해 고정층과 순환유동층에서 층물질로 석회석과 상용 순롼 유동층 하부회를 이용하여 환원실험을 수행하였으며 CaSO_4의 환원반응에 미치는 온도와 CO의 영향을 측정 및 해석하였다. 고온조건에서 CO가 환원제로 작용하여 C_aSO_4로부터 SO_2가 재배출되는 현상을 확인하였으며 CaSO_4로부터 SO_2의 재배출은 온도와 CO농도가 증가함에 따라 증가하였다. 본 실험의 결과에 의해 온도가 증가함에 따라 석회석에 의한 탈황율이 감소하는 현상을 환원이론으로 설명할 수 있다는 것이 확인되었다. For qualitative understanding of the sulphur capture process in a circulating fluidized bed fumace, the effects of temperature and CO concentration on the reactivity of partially sulfated CaO were experimentally examined. The tests were performed in a fixed bed reactor and lab-scale circulating fluidized bed reactor. The materials used were partially sulfated domestic limestone and bottom ash drained from commercial circulating fluidized bed furnaces. The re-emission of SO_2 from partially sulfated limestone and bottom ash increases with temperature as well as with concentration of the reducing agent CO. From the results of this study, the temperature dependence of sulfation could be explained by reduction theory.

고온건식탈황 유동층 반응기에서 아연계 탈황제의 재생반응에 미치는 산소농도의 영향

조성호,이봉희,진경태,이창근 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.6

Zinc titanate 탈황제를 사용하여 내경 4.5㎝인 소형유동층 반응기에서 재생반응특성을 연구하였다. 산소농도를 5%에서 21%까지 변화시키면서 재생실험을 수행하였다. 산소의 농도변화에 따라 배출되는 SO_2의 최대농도는 양론적으로 이론치와 일치하였다. 발열반응으로 인한 재생반응기의 온도상승은 산소농도가 증가함에 따라 증가하였다. 2차 황화반응 초기에 SO_2가 발생되지 않는 것으로 보아 sulfate가 형성되지 않았다는 것을 확인할 수 있었다. 재생반응 후 시료의 물리-화학적 특성 분석결과 zinc titanate 탈황제는 부반응 및 물성변화가 없는 것으로 판단할 수 있었다. 이와 같은 실험으로 분무 건조법으로 성형된 zinc titanate 탈황제는 유동층 반응기에서 산소농도 21%의 공기로 재생 가능성을 보여 주었다. The regeneration characteristics of spray-dried zinc titanate sorbent in a fluidized bed reactor were examined at temperatures of 650℃ and 700℃ with the regenerated gas of the oxygen concentrations from 5% to 21%. The outlet SO_2 peak concentrations were coincided with the theoretical values depending on inlet O_2 concentration. As the oxygen concentration was increased, the temperature rise in the regeneration reactor was increased due to the heat of exothermic reaction. During the initial stage of the second sulfidation reaction, SO_2 was not detected in the outlet gases. It was an indirect indication that zinc sulfate had not been formed during the first regeneration reaction. The various analysis results showed little differences in physical and chemical properties between fresh and regenerated sorbent.

Poster Session:PS 1203 ; Cardiology : Predictive Factors of Reversibility in Patients with Severe Tricuspid Regurgitation

( Jae Yeong Cho ),( Kye Hun Kim ),( Kyung Jin Lee ),( Yi Rang Yim ),( Sung Soo Kim ),( Hae Chang Jeong ),( Ki Hong Lee ),( Keun Ho Park ),( Doo Sun Sim ),( Hyun Ju Yoon ),( Nam Sik Yun ),( Young Joon 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background:Since severe tricuspid regurgitation (TR) is an uncommon fi nding which develops in various conditions, the present study aimed to investigate etiology, clinical characteristics, and predictors of reversibility in patients with severe TR. Methods:A total of 232 patients (67. 4±14. 1 years, 80 males) who were diagnosed with severe TR by echocardiography were enrolled. Severe TR was defi ned as vena contracta width greater than 0. 7 cm and systolic fi ow reversal in hepatic veins according to the current guideline of American Society of Echocardiography (ASE). Improvement of TR to moderate or less degree on follow up echocardiography was considered as reversible TR in the present study. Primary end points were adverse events at long-term follow-up. Adverse events were defi ned as all-cause death and operation due to severe TR. Results: Reversible TR was observed in 35 out of 153 patients (23. 0%). Sixty-one patients showed clinical improvement, but the degree of TR was not changed. Forty-nine patients (32%) who did not show clinical improvement despite of medical therapy eventually underwent surgical correction of TR, and 7 patients died. In addition, 17 patients died without operation, so 24 deaths (16%) were observed in total. finally, total adverse events developed in 66 patients (41%) during 2 years of follow-up period. Logistic regression analysis revealed prosthetic mitral valve was the only independent predictors of future adverse events (OR 2. 47, 95%CI 1. 05-5. 77, p=0. 038). Independent predictors of improved TR turned out to be the use of RAAS blockade (HR 3. 02, 95%CI 1. 12-8. 17, p=0. 030) and the use of spironolactone (HR 3. 39, 95%CI 1. 05-10. 90, p=0. 041). Low ejection fraction (LVEF <50%) also had a trend toward the reversibility (HR 2. 82, 95%CI 0. 94-8. 40). Conclusions:Considering results above, reversible severe TR mainly associated with left heart failure and medical treatment should be given before considering surgery for severe TR.

공기재생용 고온건식탈황제의 가압유동층 반응기에서의 사이클 성능실험

조성호,이봉희,이중범,류청걸,진경태,이창근 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.2

고온고압 기포유동층 반응기에서 분무건조기로 성형제조한 아연계 탈황제(ZAC C)에 대하여 총 6회 황화-재생 반복실험을 500℃, 5atm 조건에서 수행하였다. 1% H_2S를 포함한 석탄모사가스를 반응기에 주입하여 황화반응을 시킨 결과 배출가스 중 H_2S 농도는 10ppmv 이하로 유지되었다. ZAC C의 황흡수력은 6회 황화반응 동안 각각 11.1, 10.9, 11.1, 11.1, 10.9, 10.5g S/100g sorbent으로 유지되어 초기 황흡수력을 유지하였다. 공기를 이용한 500℃ 재생반응에서 배출되는 SO_2의 최대농도는 양론적으로 이론값과 일치하였다. 재생반응에서 탈황제 층의 온도는 발열반응에 의해 500℃에서 최대 750℃까지 상승하였다. 연속 70시간 동안 유동층 반응기내에서 실시된 ZAC C 탈황제의 비산되어 유출된 양은 1.07%이고, 실험 후 탈황제의 크기와 조직특성의 변화도 적었다. 고온고압반응기 multi-cyclone 실험결과 ZAC C 탈황제는 이론 황흡수력의 50% 이상을 유지하였고, 공기를 사용한 500℃의 재생반응이 원활하고 완전히 이루어졌고, 황산염생성과 같은 부반응이 없었다. Two desulfurization-regeneration experiments for a spray-dried zinc-based sorbent(ZAC C) were performed at 500℃ and 5 atm in a fluidized-bed reactor(ID 0.097㎜) facility. The H_S concentration after each desulfurization run was maintained below 10 ppmv from a simulated coal gas of 1% H_2S. The estimated sulfur absorption capacities of ZAC C sorbent were 11.1, 10.9, 11.1, 11.1, 10.9, 10.5 g S/100g sorbent, and the sorption capacity of sorbent was maintained in spite of six times sorption experiments. The maximum SO_2 concentration in regeneration effluent gas agreed with a stoichiometric value of 500℃(ca. 14vol%). In regeneration run, the peak temperature of sorbent bed in the reactor reached up to 750 due to the vigorous exothermicity of regeneration reaction with neat air. While entrainment rate for 70h continuous run in fluidized-bed reactor is 1.07%, the size and the textural properties of ZAC C sorbent also show a little change. Multi-cycle tests in fluidized-bed show that ZAC C sorbent maintains over 50% of its theoretical sorption capacity during 70h run and regeneration reaction undergoes smoothly and completely without side reactions such as sulfate formation.

AXIAL VOIDAGE PROFILE IN A COLD MODEL CIRCULATING FLUIDIZED BED

Yi, Chang Keun,Choi, Jeong Hoo,Son, Jae Ek 한국화학공학회 1990 Korean Journal of Chemical Engineering Vol.7 No.4

The axial voidage profile was measured in a cold model circulating fluidized bed (0.38 m in diameter and 9.1 m in height) of sand particles as bed materials. Voidage in the riser column increases along the height above the distributor plate with increasing the gas velocity. However, it decreases with an increase in solid circulation rate in the bed. Model correlations to predict the solid circulation rate and the axial voidage profile in the bed are proposed.

BIOLOGY OF A Cronartium BLISTER RUST ON Pinus densiflora

Chang Keun Yi,Hyun Joong Kim,Yong Joon La 한국산림과학회 1985 한국산림과학회지 Vol.71 No.1

Among the genus Cronartium, C. ribicola and C. quercuum have been recorded as the only species in Korea. In 1978, we discovered a Japanese red pine (Pious densiflora S. et Z.) infected with a stem rust in a pine plantation in Taebaeg-shi, Kangweon-do. Again in spring of 1985, a Japanese red pine tree with typical blister symptom was discovered in a P, densiflora plantation in Youngduk-gun, Gyeongsangbuk-do. Accordingly studies were carried out on its morphology and etiology to identify this rust. Aeciospores on the Japanese red pine and urediniospores on its alternate hosts, i.e., Paeonia spp., were indistinguishable from the aeciospores and urediniospores of the white pine blister rust in morphology when observed by the optical microscope and the scanning electron microscope. When the aeciospores of C. flaccidum were inoculated on some suspected alternate hosts in a growth cabinet, a large number of uredia appeared on undersurface of the leaves of Paeonia spp. and Pedicularis resupinata after 20 and 30 days, respectively following inoculation. In germination test, more than one percent of the aeciospotes of both C. ribicola and C. flaccidum remained viable for 90 days when they were stored in dark at 5℃. But regardless of the light condition,aeciospores of both species failed to germinate when stored at 20℃ for 30 days. The germination rate of the urediniospores of C. flaccidum from the Paeonia albiflora was about 1.5% when they were maintained at 21℃ with 100% relative humidity for 24 hours. C. ribicola having white pine as host and C. flaccidum having Japanese red pine as host were found to infect Pedicularis resupinata also.

Spatial and Seasonal Variations of Surface PM10 Concentration and MODIS Aerosol Optical Depth over China

Chang-Keun Song,Chang-Hoi Ho,Rokjin J. Park,Yong-Sang Choi,Jhoon Kim,Dao-Yi Gong,Yun-Bok Lee 한국기상학회 2009 Asia-Pacific Journal of Atmospheric Sciences Vol.45 No.1

가열처리에 따른 구기자 추출물의 성분변화

이상덕(Sang Duck Yi),이미현(Mi Hyun Lee),손현주(Hyun Ju Son),복진영(Jin Young Bock),성창근(Chang Keun Sung),오만근(Man Jin Oh),김찬조(Chan Jo Kim) 한국응용생명화학회 1996 Applied Biological Chemistry (Appl Biol Chem) Vol.39 No.4

Fundamental data for new type of product development from Lycii fructus was experimentally determined. The chemical composition, and Hunter value changes, optimum extraction, volatile components of extract under different extraction conditions and heat treatment were mainly studied. Results are summarized as follows. The proximate compositions of dried Lycii fructus were water 21.8%, total sugar 27.6%, reducing sugar 15.29%, crude protein 14.29%, crude fat 5.65%, crude fiber 7.48%, and ash 7.98% in percent scale, respectively. Extracted yield on the basic of solid extract was getting increased when more solvent was used for extraction. The most recommendable extraction was 1 to 10 part of sample to solvent ratio. When water was employed as extraction solvent, the highest amount of solid extract was obtained. Extract of Lycii fructus in terms of yields and color was most acceptable when raw sample was treated 8 minute roasting at 180℃ and 60 minute heating at 120℃, respectively. Major volatile components of fresh Lycii fructus were to hexadecanoic acid, methyl linoleate, benzyl alcohol, dimetane benzene by GC/MS. By she roasting of raw sample, the compounds of 2-methyl-2buthenal, 1,4-dimethyl benzene, and benzyl alcohol were reduced. Whereas, methyl thiopropanol, benzene acetaldehyde and ethyl linoleate were slightly increased.

NEW PLANT DEMONSTRATING CO₂ CAPTURE FROM REAL COAL-FIRED POWER PLANT BY DRY SORBENT

Chang-Keun YI,Sung-Ho JO,Young Cheol PARK,Hang-Dae JO,Dae-Hyun KYUNG,Jae-Young KIM 한국신재생에너지학회 2014 AFORE Vol.2014 No.-

Invitation Ⅱ

Chang-Keun Yi 한국신재생에너지학회 2022 AFORE Vol.2022 No.9