Sn-Zr계 촉매 상에서 CO와 H₂를 이용한 SO₂ 환원 반응특성

한기보,박노국,류시옥,이태진,Han, Gi Bo,Park, No-Kuk,Ryu, Si Ok,Lee, Tae Jin 한국화학공학회 2006 Korean Chemical Engineering Research(HWAHAK KONGHA Vol. No.

본 연구에서는 석탄가스화복합발전(integrated gas combined cycle, 이하 IGCC) 시스템의 석탄가스화기로부터 생산되는 석탄가스가 환원제로 이용되는 $SO_2$ 환원공정인 직접 황 회수 공정(direct sulfur recovery process, 이하 DSRP)에서 이용 가능한 Sn-Zr계 촉매 상에서의 $SO_2$ 환원반응특성을 조사하였다. Sn-Zr계 촉매는 0/1, 1/4, 1/1, 2/1, 3/1, 1/0의 Sn/Zr 몰비로 조절하여 침전법 및 공침법으로 제조되었다. 공간속도가 $10,000ml/g_{-cat.}{\cdot}h$, 반응물 몰비$([CO(or\;H_2)]/[SO_2])$가 2.0인 반응조건 하에서 Sn-Zr계 촉매를 이용하여 온도를 변화시킨 가운데 석탄가스에 포함되어 있는 $H_2$ 또는 CO를 환원제로 사용하여 $SO_2$ 환원에 대한 반응특성이 조사되었다. 실험 결과, 환원제의 종류에 상관없이 $SnO_2$와 $ZrO_2$보다 Sn-Zr계 촉매가 활성이 더 높았으며, 환원제의 종류에 대한 반응성 조사 결과, $H_2$보다 CO가 $SO_2$ 환원에 더 높은 반응성을 나타내었다. $H_2$가 환원제로 이용된 $SO_2$ 환원특성을 조사한 결과, Sn/Zr 비에 따라 제조된 Sn-Zr계 촉매의 종류에 상관없이 온도가 증가함에 따라 반응성이 증가하는 경향을 보이며 Sn/Zr 몰비가 1/4인 촉매를 사용한 경우 $550^{\circ}C$에서 $SO_2$전환율이 94.4%, 원소 황 수율이 66.4%로 높은 반응성을 나타내었다. 반면 CO를 환원제로 이용한 경우에는 Sn/Zr 몰비가 높은 촉매일수록 최적 반응온도가 감소되는 특이한 경향을 나타내었다. Sn-Zr계 촉매 중 Sn/Zr 몰비가 3/1인 $SnO_2-ZrO_2$ 촉매가 가장 낮은 최적 반응온도에서 높은 반응성을 나타내었는데, $325^{\circ}C$에서 $SO_2$전환율이 약 100%, 원소 황 수율이 약 99.5%로 가장 높은 반응성을 얻었다. 그리고 CO가 $H_2$보다 더 많이 포함되어 있는 석탄모사가스에 대하여 환원제로서의 이용가능성을 확인하고자 $CO/H_2$ 비를 달리한 각각의 합성가스에 대하여 $SO_2$ 환원반응실험을 수행하였다. Sn/Zr 몰비가 2/1인 Sn-Zr계 촉매 상에서 $SO_2$ 환원반응 실험 결과, CO 함량이 높은 합성가스일수록 효과적인 환원제임을 확인할 수 있었다. 따라서 Sn-Zr계 촉매가 적용된 DSRP에서 석탄모사가스가 환원제로 이용 가능하다는 것을 알 수 있었다. The $SO_2$ reduction using CO and $H_2$ over Sn-Zr based catalysts was performed in this study. Sn-Zr based catalysts with Sn/Zr molar ratio (0/1, 1/4, 1/1, 2/1, 3/1, 1/0) were prepared by the precipitation and co-precipitation method. The effect of the temperature on the reaction characteristics of the $SO_2$ reduction with a reducing agent such as $H_2$ and CO was investigated under the conditions of space velocity of $10,000ml/g_{-cat.}h$, $([CO(or\;H_2)]/[SO_2])$ of 2.0. As a result, the activity of Sn-Zr based catalysts were higher than $SnO_2$ and $ZrO_2$. The reactivity for the $SO_2$ reduction with CO was higher than that with $H_2$, and sulfur yield in the $SO_2$ reduction by $H_2$ was higher than that by CO. The reactivity for the $SO_2$ reduction with $H_2$ was increased with the reaction temperature regardless of Sn-Zr based catalyst with a Sn/Zr molar ratio. $SnO_2-ZrO_2$ (Sn/Zr=1/4) had highest activity at $550^{\circ}C$, in the $SO_2$ reduction with $H_2$ and $SO_2$ conversion of 94.4% and sulfur yield of 66.4% were obtained at $550^{\circ}C$. On the other hand, in the $SO_2$ reduction by CO, the reactivity was decreased with the increase over $325^{\circ}C$. At the optimal temperature of $325^{\circ}C$, $SO_2$ conversion and sulfur yield were about 100% and 99.5%, respectively, in the $SO_2$ reduction over $SnO_2-ZrO_2$ (Sn/Zr=3/1). Also, the $SO_2$ reduction using syngas with $CO/H_2$ ratio over $SnO_2-ZrO_2$ (Sn/Zr=2/1) was performed in order to investigate the application possibility of the simulated coal gas as the reductant in DSRP. As a result, the reactivity of the $SO_2$ reduction using syngas with $CO/H_2$ ratio was increased with increasing the CO content of syngas. Therefore, it could be known that DSRP using the simulated coal gas over Sn-Zr based catalyst is possible to be realized in IGCC system

석탄가스를 이용한 직접 황 회수공정을 위한 SnO₂-ZrO₂(Sn/Zr=2/1) 촉매 상에서의 CO에 의한 SO₂ 환원 반응: 반응조건 최적화 및 수분의 영향

한기보,신부영,이태진,Han, Gi Bo,Shin, Boo-Young,Lee, Tae Jin 한국공업화학회 2007 공업화학 Vol.18 No.2

본 연구에서는 $SnO_2-ZrO_2$(Sn/Zr = 2/1) 촉매 상에서의 CO에 의한 $SO_2$ 환원반응에 대한 반응온도, 공간속도, [CO]/[$SO_2$] 몰비 등의 반응조건의 최적화를 위한 반응특성을 조사하였다. $300{\sim}550^{\circ}C$의 반응온도, $5000{\sim}30000cm^3/g_{-cat}{\cdot}h$의 공간속도, 1.0~4.0 의 [CO]/[$SO_2$] 몰비 등 다양한 반응조건 범위에서 CO에 의한 $SO_2$ 환원반응에 대한 영향을 살펴본 결과, 최적 반응조건으로 반응온도, 공간속도, [CO]/[$SO_2$] 몰비는 각각 $325^{\circ}C$, $10000cm^3/[g_{-cat}{\cdot}h]$, 2.0이었다. 이 때 $SO_2$ 전환율은 약 99% 이상이었으며, 원소 황 선택도는 95% 이상이었다. 또한 CO에 의한 $SO_2$ 환원반응에서 수분에 대한 영향을 조사한 결과, 수분함량이 2.0~6.0 vol%인 범위에서 수분의 함량이 높을수록 $SO_2$ 전환율 및 원소 황 선택도가 감소됨과 동시에 반응성이 저하됨을 알 수 있었다. 2 vol%의 수분이 함유된 반응조건에서 반응온도와 [CO]/[$SO_2$] 몰비를 각각 $300{\sim}400^{\circ}C$ 및 1.0~3.0으로 변화시킨 결과, 반응온도와 [CO]/[$SO_2$] 몰비가 각각 $340^{\circ}C$와 2.0인 조건에서 가장 높은 반응성을 얻었다. 이 때 $SO_2$ 전환율이 약 90%였으며, 원소 황 선택도는 약 87%였다

SO₃ ²⁻/SO₄ ²⁻ functionalization-tailorable catalytic surface features of Sb-promoted Cu₃V₂O₈ on TiO₂ for selective catalytic reduction of NO_X

Kim, Jongsik,Lee, Somin,Kwon, Dong Wook,Lee, Kwan-Young,Ha, Heon Phil Elsevier 2019 Applied Catalysis A Vol.570 No.-

<P><B>Abstract</B></P> <P>SO<SUB>2</SUB> is notorious to poison the catalytic surface during the selective catalytic reduction of NO<SUB>X</SUB> with NH<SUB>3</SUB> (NH<SUB>3</SUB>-SCR). Nonetheless, the use of poisonous SO<SUB>2</SUB> and O<SUB>2</SUB> as surface modifiers to generate the surface metal-SO<SUB>Y</SUB> <SUP>2−</SUP> species (Y = 3 or 4) can be one of the viable ways for promoting catalytic NH<SUB>3</SUB>-SCR consequence. To develop a novel catalyst that is highly active in and selective to NH<SUB>3</SUB>-SCR, we previously explored four catalytic copper vanadates and determined the optimum active phase (i.e., Cu<SUB>3</SUB>V<SUB>2</SUB>O<SUB>8</SUB>, denoted as Cu<SUB>3</SUB>) that revealed the greatest NH<SUB>3</SUB>-SCR performance, when combining with a proper Sb quantity of 1.4 wt. %. While using anatase (TiO<SUB>2</SUB>) as a support, this study investigated the effect of SO<SUB>Y</SUB> <SUP>2−</SUP> functionalization temperature on the surface property of the optimum catalyst, Sb-promoted Cu<SUB>3</SUB>V<SUB>2</SUB>O<SUB>8</SUB> on TiO<SUB>2</SUB> (Cu<SUB>3</SUB>-Sb<SUB>1.4</SUB>/TiO<SUB>2</SUB>). Cu<SUB>3</SUB>-Sb<SUB>1.4</SUB>/TiO<SUB>2</SUB> was subjected to SO<SUB>Y</SUB> <SUP>2−</SUP> functionalization at 300, 400, and 500 °C, leading to the formation of S300, S400, and S500. Although the catalyst surface was not fully functionalized with the SO<SUB>Y</SUB> <SUP>2−</SUP> species in S300-S500, various metal sulfate or sulfite species appeared on the surfaces and showed distinct surface features. The SO<SUB>Y</SUB> <SUP>2−</SUP> functionalization of Cu<SUB>3</SUB>-Sb<SUB>1.4</SUB>/TiO<SUB>2</SUB> could not increase the quantity of Lewis acid sites. However, 400 °C was deemed as an adequate SO<SUB>Y</SUB> <SUP>2−</SUP> functionalization temperature for increasing the quantity of Brӧnsted acid sites and the redox behavior of the intact Cu<SUB>3</SUB>-Sb<SUB>1.4</SUB>/TiO<SUB>2</SUB>. This could result from the increase in the surface abundance of Cu(SO<SUB>4</SUB>) or from a proper combination of the metal-bound SO<SUB>Y</SUB> <SUP>2−</SUP> species with <I>mono</I>-dentate and <I>bi</I>-dentate binding configurations. Apart from exhibiting moderate tolerance to hydrothermal aging, S400 was also validated to improve its resistance to alkali-metal, H<SUB>2</SUB>O, SO<SUB>2</SUB>, (NH<SUB>4</SUB>)<SUB>2</SUB>SO<SUB>4</SUB>, or (NH<SUB>4</SUB>)HSO<SUB>4</SUB> in comparison to its SO<SUB>Y</SUB> <SUP>2−</SUP>-unfunctionalized counterpart, S300, and S500.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sb-promoted Cu<SUB>3</SUB>V<SUB>2</SUB>O<SUB>8</SUB> subjected to SO<SUB>Y</SUB> <SUP>2−</SUP>-functionalization at 300–500 °C to obtain S300-S500. </LI> <LI> S400 populated the metal-SO<SUB>Y</SUB> <SUP>2−</SUP> surface species, yet balanced the ionic and covalent features. </LI> <LI> S400 promoted NH<SUB>3</SUB>-SCR performance because of its enhanced quantity of acid sites and redox character. </LI> <LI> S400 exhibited moderate resistance to hydro-thermal aging during NH<SUB>3</SUB>-SCR. </LI> <LI> S400 revealed improved tolerance to alkali metal/SO<SUB>2</SUB>/H<SUB>2</SUB>O/AS/ABS species during NH<SUB>3</SUB>-SCR. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

석탄가스를 이용한 직접 황 회수공정을 위한 SnO2-ZrO2(Sn/Zr=2/1) 촉매 상에서의 CO에 의한 SO2 환원 반응: 반응조건 최적화 및 수분의 영향

한기보,이태진,신부영 한국공업화학회 2007 공업화학 Vol.18 No.2

본 연구에서는 SnO2-ZrO2(Sn/Zr = 2/1) 촉매 상에서의 CO에 의한 SO2 환원반응에 대한 반응온도, 공간속도, [CO]/[SO2] 몰비 등의 반응조건의 최적화를 위한 반응특성을 조사하였다. 300∼550 ℃의 반응온도, 5000∼30000 cm3/g-cat⋅h의 공 간속도, 1.0∼4.0 의 [CO]/[SO2] 몰비 등 다양한 반응조건 범위에서 CO에 의한 SO2 환원반응에 대한 영향을 살펴본 결과, 최적 반응조건으로 반응온도, 공간속도, [CO]/[SO2] 몰비는 각각 325 ℃, 10000 cm3/[g-cat⋅h], 2.0이었다. 이 때 SO2 전환율은 약 99% 이상이었으며, 원소 황 선택도는 95% 이상이었다. 또한 CO에 의한 SO2 환원반응에서 수분에 대한 영향을 조사한 결과, 수분함량이 2.0∼6.0 vol%인 범위에서 수분의 함량이 높을수록 SO2 전환율 및 원소 황 선택 도가 감소됨과 동시에 반응성이 저하됨을 알 수 있었다. 2 vol%의 수분이 함유된 반응조건에서 반응온도와 [CO]/[SO2] 몰비를 각각 300∼400 ℃ 및 1.0∼3.0으로 변화시킨 결과, 반응온도와 [CO]/[SO2] 몰비가 각각 340 ℃와 2.0인 조건에서 가장 높은 반응성을 얻었다. 이 때 SO2 전환율이 약 90%였으며, 원소 황 선택도는 약 87%였다.

직접 황 회수 공정으로 유입되는 재생가스에 함유된 미량산소의 촉매활성저하 원인 규명

최희영(Hee-Young Choi),박노국(No-Kuk Park),이태진(Tae Jin Lee) 한국청정기술학회 2014 청정기술 Vol.20 No.3

순산소 순환유동층에서 로내 탈황 및 탈질법 적용에 따른 오염물질 거동특성

최경구(Gyung-Goo Choi),나건수(Geon-Soo Na),신지훈(Ji-Hoon Shin),길상인(Sang-In Keel),이정규(Jung-Kyu Lee),허필우(Pil-Woo Heo),윤진한(Jin-Han Yun) 한국청정기술학회 2018 청정기술 Vol.24 No.3

Lamellar La2O2SO4:Eu3+ phosphor and its conversion to rice ear-like La2O2S:Eu3+ nanophosphor by a reduction step

Xing Li,Yudi Gao,Liying Zhang,Jingbao Lian 한양대학교 청정에너지연구소 2022 Journal of Ceramic Processing Research Vol.23 No.5

In this work, La2O2S:Eu3+ nanophosphor was successfully synthesized through a combination method of co-precipitation andfollowing reduction step, using commercial available lanthanum sulfate octahydrate, europium nitrate hexahydrate andammonia water as experimental raw materials. Fourier transform infrared spectroscopy (FTIR) results showed that theprecursor contains OH and SO42 groups. X-ray diffraction (XRD) exhibited that the composition of the precursor isLa2(OH)4SO4·2H2O. After calcination at 800 oC in muffle furnace for 2 h, the precursor was transformed into the La2O2SO4phase and then reduced to pure La2O2S phase at 800 oC for 1h under a reducing atmosphere. Differential scanningcalorimetry/thermogravimetry (DSC/TG) analysis further confirmed that the removal of crystal water and dehydroxylationprocess from La2(OH)4SO4·2H2O to La2O2SO4. Field-emission scanning electron microscopy (FESEM) observations displayedthat the morphologies of La2(OH)4SO4·2H2O and La2O2SO4 are lamellar structures, while after reduction treatment, theproduced La2O2S possesses a rice ear-like shape with particle size of 20-50 nm. Photoluminescence (PL) spectra revealed thatthe La2O2S:Eu3+ nanophosphor displays excellent photoluminescent properties, with the main emission peak at 624 nm afterphotoexcitation at 254 nm, a good CIE coordinate of (0.6669, 0.3214), a short lifetime of 1.60 ms and an appropriate CCT valueof 3951 K.

석탄가스의 초정밀 정제를 위한 변형된 활성탄의 흡착특성 연구

이유진(You Jin Lee),박노국(No-Kuk Park),이태진(Tae Jin Lee) 한국청정기술학회 2007 청정기술 Vol.13 No.4

V2O5-WO3/TiO2/SiC 촉매필터의 NO 환원에 SO2와 H2O가 미치는 영향

하지원 ( Ji Won Ha ),최주홍 ( Joo Hong Choi ) 한국화학공학회 2014 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.52 No.5

For investigating NO reduction activity of an catalytic filter, the catalytic performance was measured underthe presence of SO2 and H2O, respectively or simultaneously in the simulation gas composed of NO, NH3, and air. Thecatalytic filter was prepared by coating V2O5-WO3/TiO2 catalyst on the pore surface of SiC filter element of which thesuperior performance for the particulate removal was well known. At the temperature below 260 oC, the catalytic activitieswere enormously decreased under the presence of SO2 and H2O, respectively or simultaneously, compared withthose under the cases of the absence of SO2 and H2O. However, the presence of SO2 promoted the performance of thecatalytic filter above 320 oC with showing the NO conversion better than 99.8% for the NO inlet concentration of 500ppm and at the face velocity of 2 cm/s. In particular, the presence of water showed high NO conversion higher than 99%up to high temperature of 380 oC. This effect of water was explained by the reason that it retarded the ammonia oxidationwhich is the main step into the formation of N2O. The initial NO reduction activity of the catalytic filter maintainedfor the duration of 100 hours in the presence of SO2 and H2O. Therefore, it was concluded that the catalytic filter waspromisingly useful for the industrial NOx reduction catalyst in order to treat the particulate and NO simultaneously.

CaSO4 기반 산소전달입자의 환원과 분해특성

류호정,김하나,이동호,진경태,백점인 한국수소및신에너지학회 2015 한국수소 및 신에너지학회논문집 Vol.26 No.6

As a candidate for cheap oxygen carrier, CaSO4 based oxygen carriers have been developing. However, research on reaction characteristics and side reaction of CaSO4 based oxygen carrier is very limited. There are many possible reactions for main components of syngas from coal. In this study, we prepared three CaSO4 based oxygen carriers (CaSO4-Fe2O3/bentonite, CaSO4-K2CO3/bentonite, CaSO4-CaO/bentonite) and performed reduction tests by hydrogen. Cyclic reduction-oxidation tests up to 5 th cycle are also conducted using hydrogen as fuel. Reduction reactivity of those CaSO4 based oxygen carriers were compared with that of NiO based oxygen carrier (OCN703-1100). Real weight change fractions of CaSO4 based oxygen carriers were higher than theoretical oxyen transfer capacity and reactivity of these particles decreased with the number of cycle increased. To check possible side reaction of CaSO4 based oxygen carriers, CaSO4 decomposition tests were carried out and SO2 was detected even at 700°C. Consequently, we could conclude that CaSO4 based oxygen carriers decompose and release SO2 and this reaction lead reactivity decay of CaSO4 based oxygen carries.