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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>
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>