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Oh, Gunung,Ra, Ho Won,Yoon, Sung Min,Mun, Tae Young,Seo, Myung Won,Lee, Jae Goo,Yoon, Sang Jun Elsevier 2018 Applied thermal engineering Vol.129 No.-
<P><B>Abstract</B></P> <P>Entrained-flow gasifiers used in commercial integrated gasification combined cycles are usually oxygen-blown. However, oxygen-blown gasification system is expensive to install and operate due to the equipment involved in oxygen purification and supply. To resolve this issue, this study mixed air and oxygen to perform coal gasification. An entrained-flow gasifier of 1 T/D scale was used with the coal water mixture as feedstock. Gasification was carried out at a temperature range of 970–1220 °C, an equivalence ratio of 0.25–0.62, and an air/O<SUB>2</SUB> ratio of 2.17–9.0. With an increasing gasification temperature, the amount of CO in the syngas increased while CO<SUB>2</SUB> and CH<SUB>4</SUB> decreased. Carbon conversion and cold gas efficiency continued to increase with the gasification temperature. In the equivalence ratio test, cold gas efficiency reached 52.1% at around 0.53 before decreasing under a fixed air flow rate of 90 N m<SUP>3</SUP>/h. By performing gasification with a varying air/O<SUB>2</SUB> ratio after fixing the flow rate, the influence of the equivalence ratio was examined. In addition, the influence of the flow rate was observed through changes in the air/O<SUB>2</SUB> ratio of the gasification agent with fixing the equivalence ratio. The maximum carbon conversion and cold gas efficiency were 90.7 and 57.7%, respectively, and the optimal air/O<SUB>2</SUB> ratio fell in the range of 2.86–3.1.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of air and oxygen mixing ratio in an entrained-flow coal gasification is studied. </LI> <LI> Gasification efficiency was affected by feed flow rate of gasification agent. </LI> <LI> Equivalence ratio shows a significant effect on gasification than the feed flow rate. </LI> <LI> Optimal equivalence ratio and air/O<SUB>2</SUB> ratio condition were founded. </LI> </UL> </P>
Ni/Ru-X/Al₂O₃ (X=K or Mn) 촉매를 이용한 바이오매스 가스화 타르의 수증기개질
오건웅(Gunung Oh),박서윤(Seo Yoon Park),이재구(Jae-Goo Lee),김용구(Yong Ku Kim),라호원(Ho Won Ra),서명원(Myung Won Seo),윤상준(Sang Jun Yoon) 한국청정기술학회 2016 청정기술 Vol.22 No.1
바이오매스 가스화 시 발생하는 타르의 개질 연구가 다양한 Ni 촉매를 이용하여 수행되었다. 바이오매스 타르의 주요 성분인 톨루엔을 이용하여 실험실 규모의 수증기개질을 수행하였다. 고정층 형태의 개질기를 이용하였고 반응온도 범위는 400-800 ℃로 변화시켰다. Ni 촉매에 증진제로 Ru (0.6 wt%)와 Mn 또는 K (1 wt%)를 적용하였다. Ni/Ru-K/Al₂O₃ 촉매가 Ni/Ru-Mn/Al₂O₃ 촉매보다 전반적으로 높은 톨루엔 개질 전환 성능을 보였으며, X-선 회절분석과 열중량분석을 통해 촉매의 안정성을 확인하였다. 실험실 규모 연구 결과를 바탕으로 모노리스와 펠렛 형태의 촉매를 제작하고 1 톤/일 규모의 바이오매스 가스화 시스템에 적용하였다. 모노리스 촉매의 경우 Ni/Ru-K/Al₂O₃ 촉매가 고온에서 특히 우수한 성능을 보였으며, Ni/Ru-Mn/Al₂O₃ 촉매는 운전 시간 경과에 의한 활성저하가 관찰되었다. 펠렛 촉매의 경우 Ni/Ru-K/Al₂O₃ 는 587 ℃에서 66.7%의 타르 전환율을 보였으며, 사용된 촉매의 재생 후 타르 개질 성능을 비교하였다. 본 연구에서 사용된 촉매 중 Ni/Ru-K/Al₂O₃ 펠렛 촉매가 가장 우수한 촉매 활성과 안정성을 보였다. Steam reforming of tar produced from biomass gasification was conducted using several Ni-based catalysts. In labscale, the catalytic steam reforming of toluene which is a major component of biomass tar was studied. A fixed bed reactor was used at various temperatures of 400-800 ℃. Ru (0.6 wt%) and Mn or K (1 wt%) were applied as a promoter in Ni based catalysts. Generally, Ni/Ru-K/Al₂O₃ catalyst shows higher performance on steam reforming of toluene than Ni/Ru-Mn/Al₂O₃ catalyst. Used catalysts were analyzed by XRD and TGA to detect sintering and carbon deposition. Base on the lab-scale studies, the monolith and pellet type catalysts were tested in 1 ton/day scale biomass gasification system. Ni/Ru-K/Al₂O₃ monolith catalyst shows high tar reforming performance at high temperature. In addition, Ni/Ru-Mn/Al₂O₃ monolith catalyst was showed deactivation with operation time. Reforming performance of Ni/Ru-K/Al₂O₃ pellet catalyst which showed 66.7% tar conversion at 587 ℃ was compared to regenerated one. Overall, Ni/Ru-K/Al₂O₃ pellet catalyst shows higher stability and performance than other used catalysts.
Steam Reforming of Toluene Over Ni/Coal Ash Catalysts: Effect of Coal Ash Composition
( Jinyoung Jang ),( Gunung Oh ),( Ho Won Ra ),( Sung Min Yoon ),( Tae Young Mun ),( Myung Won Seo ),( Jihong Moon ),( Jae-goo Lee ),( Sang Jun Yoon ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.2
The development of a low cost catalyst with high performance and small amount of carbon deposition on catalyst from toluene steam reforming were investigated by using coal ash as a support material. Ni-loaded coal ash catalyst showed similar catalytic activity for toluene steam reforming compared with the Ni/Al<sub>2</sub>O<sub>3</sub>. At 800℃, the toluene conversion was 77% for Ni/TAL, 68% for Ni/KPU and 78% for Ni/Al<sub>2</sub>O<sub>3</sub>. Ni/TAL showed similar toluene conversion to Ni/Al<sub>2</sub>O<sub>3</sub>. However, Ni/KPU produced higher hydrogen yield at relatively lower toluene conversion. Ni/KPU catalyst showed a remarkable ability of suppressing the carbon deposition. The difference in coke deposition and hydrogen yield is due to the composition of KPU ash (Ca and Fe) which increase coke resistance and water gas shift reaction. This study suggests that coal ash catalysts have great potential for the application in the steam reforming of biomass tar.
Deactivation characteristics of Ni and Ru catalysts in tar steam reforming
Park, Seo Yun,Oh, Gunung,Kim, Kwangyul,Seo, Myung Won,Ra, Ho Won,Mun, Tae Young,Lee, Jae Goo,Yoon, Sang Jun Elsevier 2017 RENEWABLE ENERGY Vol.105 No.-
<P><B>Abstract</B></P> <P>Tar formation resulting during lignocellulosic biomass gasification is a major impediment to utilizing biomass energy sources, in that it blocks and fouls the processing equipment; as such, any tar present in the produced syngas much be effectively removed. This study analyzes the ability of commercially available Ni and Ru based CH<SUB>4</SUB> reforming catalysts to effect tar removal and compares deactivation characteristics. Toluene was used as the model biomass tar at concentrations of 30 and 100 g/Nm<SUP>3</SUP>. Several additional parameters were also tested, including reaction temperatures (400–800 °C), space velocities (5000–30,000 h<SUP>−1</SUP>), and the steam/toluene ratios (2–20). The variation of toluene conversion and product gas composition with reaction conditions was analyzed. Overall, H<SUB>2</SUB> and CO production were favored by the Ru catalyst and generally increased with temperature. Conversion also increased with temperature, with conversions higher than 90% obtained at 800 °C.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ru-containing RUA and Ni-containing FCR-4 were tested as tar reforming catalysts. </LI> <LI> Toluene was used as the model tar at both standard and high concentrations. </LI> <LI> Both catalysts effected over 90% conversion at 800 °C for standard toluene loading. </LI> <LI> Conversion increased with steam content and decreased as space velocity increased. </LI> <LI> FCR-4 showed significantly greater coke deposition, accounting for deactivation. </LI> </UL> </P>