3 research outputs found

    ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๋‹ˆ์ผˆ ๊ธฐ๋ฐ˜ ์ด‰๋งค์ƒ์—์„œ์˜ LNG ์ˆ˜์ฆ๊ธฐ ๊ฐœ์งˆ๋ฐ˜์‘์„ ํ†ตํ•œ ์ˆ˜์†Œ ์ƒ์‚ฐ ์—ฐ๊ตฌ

    No full text
    ํ•™์œ„๋…ผ๋ฌธ(๋ฐ•์‚ฌ)--์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› :๊ณต๊ณผ๋Œ€ํ•™ ํ™”ํ•™์ƒ๋ฌผ๊ณตํ•™๋ถ€,2020. 2. ๊น€๋„ํฌ.์‹ ์žฌ์ƒ์—๋„ˆ์ง€๋Š” ํ™˜๊ฒฝ์— ์˜ํ–ฅ์„ ์ตœ์†Œํ•œ์œผ๋กœ ๋ผ์น˜๋Š” ์ฒญ์ • ์—๋„ˆ์ง€ ์›์œผ๋กœ ๊ฐ„์ฃผ๋œ๋‹ค. ๊ทธ ์ค‘์—์„œ๋„ ์ˆ˜์†Œ ์—๋„ˆ์ง€์›์€ ์—ฐ์†Œ ์ค‘์— NOx ๋ฐ SOx์™€ ๊ฐ™์€ ์˜ค์—ผ ๋ฌผ์งˆ์„ ๋ฐฉ์ถœํ•˜์ง€ ์•Š๊ธฐ ๋•Œ๋ฌธ์— ๊ฐ€์žฅ ์œ ๋งํ•œ ์ฒญ์ •์—๋„ˆ์ง€ ์šด๋ฐ˜์ฒด๋กœ ๋งŽ์€ ๊ด€์‹ฌ์„ ๋ฐ›๊ณ  ์žˆ๋‹ค. ๋˜ํ•œ, ์ˆ˜์†Œ์˜ ๋†’์€ ์—๋„ˆ์ง€ ๋ฐ€๋„๋Š” ์ˆ˜์†Œ์˜ ๋˜ ๋‹ค๋ฅธ ํฐ ์ด์ ์ด๋‹ค. ์ด๋Ÿฌํ•œ ํŠน์„ฑ๋“ค ๋•Œ๋ฌธ์— ์ˆ˜์†Œ ์ž๋™์ฐจ, ์ˆ˜์†Œ ์—ฐ์†Œ ์—”์ง„ ๋ฐ ์—ฐ๋ฃŒ ์ „์ง€์™€ ๊ฐ™์€ ์ˆ˜์†Œ ํ™œ์šฉ ๋ถ„์•ผ์˜ ํ™œ๋ฐœํ•œ ์—ฐ๊ตฌ๋กœ ์ด์–ด์กŒ๋‹ค. ์ด๋ฅผ ์œ„ํ•ด ์ˆ˜์†Œ ์ƒ์‚ฐ์„ ์œ„ํ•œ ํƒ„ํ™”์ˆ˜์†Œ๋ฅผ ์ด์šฉํ•œ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘, ๋ถ€๋ถ„์‚ฐํ™”๋ฐ˜์‘, ์ž์—ด๊ฐœ์งˆ๋ฐ˜์‘, ๊ทธ๋ฆฌ๊ณ  ๊ฑด์กฐ๊ฐœ์งˆ๋ฐ˜์‘๊ณผ ๊ฐ™์€ ์ด‰๋งค๊ฐœ์งˆ๊ณต์ •์ด ๊ด‘๋ฒ”์œ„ํ•˜๊ฒŒ ์—ฐ๊ตฌ๋˜๊ณ  ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ฐœ์งˆ ๊ณต์ • ์ค‘, ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์€ ๋†’์€ ๊ฒฝ์ œ์  ์ด์ ์œผ๋กœ ์ธํ•ด ์ˆ˜์†Œ ์ƒ์‚ฐ์— ๋„๋ฆฌ ์‚ฌ์šฉ๋˜์–ด์™”๋‹ค. ๋˜ํ•œ, ์ฃผ๋กœ ํ’๋ถ€ํ•œ ์–‘์˜ ๋ฉ”ํƒ„์œผ๋กœ ๊ตฌ์„ฑ๋œ ์•กํ™”์ฒœ์—ฐ๊ฐ€์Šค (LNG)๋Š” ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์— ์˜ํ•œ ์ˆ˜์†Œ ์ƒ์‚ฐ์˜ ์ฃผ์š” ๊ณต๊ธ‰์›์œผ๋กœ ์‚ฌ์šฉ๋  ์ˆ˜ ์žˆ๋‹ค. ํ˜„๋Œ€ ๋„์‹œ์—์„œ LNG ํŒŒ์ดํ”„ ๋ผ์ธ์ด ๋„๋ฆฌ ๋ณด๊ธ‰๋˜์–ด์žˆ๊ธฐ ๋•Œ๋ฌธ์— LNG๋Š” ์—ฐ๋ฃŒ์ „์ง€์‹œ์Šคํ…œ์˜ ์ค‘์š”ํ•œ ์ˆ˜์†Œ ๊ณต๊ธ‰์›์œผ๋กœ์จ ํฐ ๊ฐ€๋Šฅ์„ฑ์ด ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ๊ด€์ ์—์„œ ๊ณ ํšจ์œจ๊ณต์ •์„ ์œ„ํ•œ LNG ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘ ์ด‰๋งค๊ฐœ๋ฐœ์ด ํ•„์š”ํ•˜๋‹ค. ๋‹ˆ์ผˆ๊ณ„ ์ด‰๋งค๋Š” ๋ฐ˜์‘ํ™œ์„ฑ์ด ๋†’๊ณ  ๊ฐ€๊ฒฉ์ด ์‹ธ๊ธฐ ๋•Œ๋ฌธ์— ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์— ๊ฐ€์žฅ ์ ํ•ฉํ•œ ์ด‰๋งค๊ณ„๋กœ ์—ฌ๊ฒจ์ง„๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ ๋‹ˆ์ผˆ์˜ ์ตœ๋Œ€ ์ด‰๋งค ์„ฑ๋Šฅ์„ ๋‹ฌ์„ฑํ•˜๊ธฐ ์œ„ํ•ด ์ข…๋ž˜์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์€ ๋†’์€ ๋ฐ˜์‘ ์˜จ๋„ (> 800 oC), ๋†’์€ ๋ฐ˜์‘ ์••๋ ฅ (> 20 bar) ๋ฐ ๋†’์€ ์ˆ˜์ฆ๊ธฐ ๋Œ€ ํƒ„์†Œ ๋น„ (์ˆ˜์ฆ๊ธฐ/ํƒ„์†Œ> 2)์—์„œ ์ˆ˜ํ–‰๋œ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜, ์ด๋Ÿฌํ•œ ๋ฐ˜์‘ ์กฐ๊ฑด์€ ๋‚ฎ์€ ๋‚ด๊ตฌ์„ฑ ๋ฌธ์ œ๋กœ ์ธํ•ด ๋ฐ”๋žŒ์งํ•˜์ง€ ์•Š๋‹ค. ์ด๋Ÿฌํ•œ ์ด์œ ๋กœ, ์ ๋‹นํ•œ ๋ฐ˜์‘ ์กฐ๊ฑด์—์„œ ๋†’์€ ์ด‰๋งค ํ™œ์„ฑ ๋ฐ ๋‚ด๊ตฌ์„ฑ์„ ๊ฐ–๋Š” ํšจ์œจ์ ์ธ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์šฉ ์ด‰๋งค๋ฅผ ๊ฐœ๋ฐœํ•˜๋Š” ๊ฒƒ์ด ๋งค์šฐ ์ค‘์š”ํ•˜๋‹ค. ์ž˜ ๋ฐœ๋‹ฌ๋œ ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๊ตฌ์กฐ์˜ ๋‹ˆ์ผˆ-์•Œ๋ฃจ๋ฏธ๋‚˜ ์ด‰๋งค๋Š” ์•Œ๋ฃจ๋ฏธ๋‚˜ ๋‹ด์ฒด ์ƒ์˜ ๋‹ˆ์ผˆ์˜ ๋ถ„์‚ฐ๋„๋ฅผ ํ–ฅ์ƒ์‹œํ‚ฌ ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ์ด‰๋งค๋ฅผ ํ†ตํ•œ ์—ด ๋ฐ ๋ฌผ์งˆ ์ „๋‹ฌ์„ ์ด‰์ง„์‹œ์ผœ ์ด‰๋งค ์„ฑ๋Šฅ์„ ๋†’์ธ๋‹ค๊ณ  ๋ณด๊ณ ๋˜์—ˆ๋‹ค. ๋”ฐ๋ผ์„œ, ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๋‹ˆ์ผˆ-์•Œ๋ฃจ๋ฏธ๋‚˜ ์ด‰๋งค๋Š” ๊ฐœ์งˆ ๋ฐ˜์‘์—์„œ ์ด‰๋งค ํ™œ์„ฑ ๋ฐ ์•ˆ์ •์„ฑ ๋ชจ๋‘๋ฅผ ๊ฐœ์„  ์‹œํ‚ค๋Š”๋ฐ ๋งŽ์€ ๊ด€์‹ฌ์„ ๋ฐ›๊ณ  ์žˆ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ LNG์˜ ์ด‰๋งค ์ฆ๊ธฐ ๊ฐœ์งˆ์—์„œ ๋†’์€ ์ˆ˜์†Œ ์ˆ˜์œจ์„ ์–ป๊ธฐ ์œ„ํ•ด ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๋‹ˆ์ผˆ-์•Œ๋ฃจ๋ฏธ๋‚˜ ์ด‰๋งค๋ฅผ ์—ํญ์‚ฌ์ด๋“œ ๊ธฐ๋ฐ˜ ์กธ-๊ฒ”๋ฒ• ๋ฐ ์ดˆ์ž„๊ณ„ CO2 ๊ฑด์กฐ๋ฒ•์„ ํฌํ•จํ•œ ๋‹ค์–‘ํ•œ ์ œ์กฐ๋ฒ•์œผ๋กœ ๋†’์€ ๋ฌผ๋ฆฌํ™”ํ•™์  ํŠน์„ฑ์„ ๊ฐ€์ง€๋Š” ์ด‰๋งค๋ฅผ ์ œ์กฐํ–ˆ๋‹ค. ๋˜ํ•œ ๋‹ˆ์ผˆ-์•Œ๋ฃจ๋ฏธ๋‚˜ ์ด‰๋งค๋ฅผ ์ฒ  ๋˜๋Š” ๋ถ•์†Œ ์กฐ์ด‰๋งค๋ฅผ ๋„์ž…ํ•˜์—ฌ ์ด‰๋งค์˜ ๋ฌผ๋ฆฌํ™”ํ•™์ ํŠน์„ฑ์„ ์ฆ์ง„์‹œํ‚ค๊ณ ์ž ํ–ˆ๋‹ค. ์ฒ  ํ•จ๋Ÿ‰ (x = 0-10wt%)์„ ๊ฐ–๋Š” ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๋‹ˆ์ผˆ-์ฒ -์•Œ๋ฃจ๋ฏธ๋‚˜ ์ œ๋กœ์ ค ์ด‰๋งค๊ตฐ (20NixFeAl๋กœ ํ‘œ์‹œ๋จ)์„ ์—ํญ์‚ฌ์ด๋“œ ๊ธฐ๋ฐ˜ ์กธ-๊ฒ”๋ฒ•์œผ๋กœ ์ œ์กฐํ•˜์˜€๋‹ค. ์•กํ™”์ฒœ์—ฐ๊ฐ€์Šค์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์—์„œ ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๋‹ˆ์ผˆ-์ฒ -์•Œ๋ฃจ๋ฏธ๋‚˜ ์ œ๋กœ์ ค ์ด‰๋งค์˜ ๋ฌผ๋ฆฌ ํ™”ํ•™์  ํŠน์„ฑ ๋ฐ ์ด‰๋งค ํ™œ์„ฑ์— ๋Œ€ํ•œ ์ฒ  ํ•จ๋Ÿ‰์— ๋”ฐ๋ฅธ ์˜ํ–ฅ์„ ์กฐ์‚ฌํ•˜์˜€๋‹ค. ๋ชจ๋“  20NixFeAl ์ด‰๋งค๋Š” ์ž˜ ๋ฐœ๋‹ฌ๋œ ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๊ตฌ์กฐ๋ฅผ ๋‚˜ํƒ€๋‚ด๊ณ  ๋‹ˆ์ผˆ๊ณผ ์ฒ ์ด ๊ณ ๋ถ„์‚ฐ๋œ ๊ฒƒ์„ ํ™•์ธํ–ˆ๋‹ค. ์†Œ์„ฑ๋œ 20NixFeAl ์ด‰๋งค์˜ ํ™˜์›์„ฑ์€ ์ฒ  ์กฐ์ด‰๋งค ์ฒจ๊ฐ€๋กœ ํŒ”๋ฉด์ฒด ๋ฐฐ์œ„๋œ ๋‹ˆ์ผˆ์˜ ์ฆ๊ฐ€๋กœ ์ธํ•ด ํ–ฅ์ƒ๋˜์—ˆ๋‹ค. H2-TPD ๋ฐ XPS ๊ฒฐ๊ณผ๋กœ๋ถ€ํ„ฐ, 20NixFeAl ์ด‰๋งค์˜ ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์ด ์ฒ  ํ•จ๋Ÿ‰๊ณผ ๊ด€๋ จํ•˜์—ฌ ํ™”์‚ฐํ˜• ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์ด ๊ฒฐ๊ณผ๋Š” ํ™˜์›๋œ 20NixFeAl ์ด‰๋งค์ƒ์—์„œ ๋‹ˆ์ผˆ์˜ ๊ณ ๋ถ„์‚ฐ์„ ์œ„ํ•ด ์ตœ์ ์˜ ์ฒ ์˜ ๋„์ž…์ด ํ•„์š”ํ•จ์„ ์˜๋ฏธํ•œ๋‹ค. LNG์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์—์„œ, ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์ด ๊ฐ€์žฅ ๋†’์€ 20Ni4FeAl ์ด‰๋งค๋Š” LNG ์ „ํ™˜์œจ ๋ฐ ์ˆ˜์†Œ ์ˆ˜์œจ ์ธก๋ฉด์—์„œ ์ตœ๊ณ ์˜ ์ด‰๋งค ์„ฑ๋Šฅ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ๋”ฐ๋ผ์„œ ์ด‰๋งค์˜ ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์€ LNG์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์—์„œ ์ด‰๋งค ์„ฑ๋Šฅ์„ ๊ฒฐ์ •ํ•˜๋Š” ๋ฐ ์ค‘์š”ํ•œ ์—ญํ• ์„ ํ–ˆ์Œ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค. ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๋‹ˆ์ผˆ-์ฒ -์•Œ๋ฃจ๋ฏธ๋‚˜ ์—์–ด๋กœ์ ค (NFA๋กœ ํ‘œ์‹œ) ์ด‰๋งค๋Š” ๋‹จ์ผ๋‹จ๊ณ„ ์—ํญ์‚ฌ์ด๋“œ๊ธฐ๋ฐ˜ ์กธ-๊ฒ”๋ฒ• ๋ฐ ์ดˆ์ž„๊ณ„ CO2 ๊ฑด์กฐ ๋ฐฉ๋ฒ•์— ์˜ํ•ด ์ œ์กฐ๋˜์—ˆ๋‹ค. ๋น„๊ต๋ฅผ ์œ„ํ•ด, ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๋‹ˆ์ผˆ-์ฒ -์•Œ๋ฃจ๋ฏธ๋‚˜ ์ œ๋กœ์ ค (NFX๋กœ ํ‘œ์‹œ๋จ) ์ด‰๋งค๋Š” ๋˜ํ•œ ๋‹จ์ผ๋‹จ๊ณ„ ์—ํญ์‚ฌ์ด๋“œ๊ธฐ๋ฐ˜ ์กธ-๊ฒ” ๋ฒ• ๋ฐ ์ผ๋ฐ˜ ๊ฑด์กฐ ๋ฐฉ๋ฒ•์— ์˜ํ•ด ์ œ์กฐ๋˜์—ˆ๋‹ค. ๋‘ ์ด‰๋งค ๋ชจ๋‘ ์ˆ˜์†Œ ์ƒ์‚ฐ์„ ์œ„ํ•œ ์•กํ™”์ฒœ์—ฐ๊ฐ€์Šค์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์— ์ ์šฉ๋˜์—ˆ๋‹ค. ์ด‰๋งค์˜ ๋ฌผ๋ฆฌํ™”ํ•™์  ํŠน์„ฑ ๋ฐ ๋ฐ˜์‘ํ™œ์„ฑ์— ๋Œ€ํ•œ ๊ฑด์กฐ๋ฐฉ์‹์˜ ์˜ํ–ฅ์„ ์กฐ์‚ฌํ•˜์˜€๋‹ค. ์ดˆ์ž„๊ณ„ CO2 ๊ฑด์กฐ ๋ฐฉ๋ฒ•์ด NFA ์ด‰๋งค์˜ ๋ฌผ๋ฆฌ์ ํŠน์„ฑ์„ ํ–ฅ์ƒ์‹œํ‚ค๋Š” ๋ฐ ํšจ๊ณผ์ ์ด๋ผ๋Š” ๊ฒƒ์ด ๋ฐํ˜€์กŒ๋‹ค. XRD ๋ฐ TPR ๊ฒฐ๊ณผ๋Š” ๋‘ ์ด‰๋งค ๋ชจ๋‘ ๋‹ˆ์ผˆ, ์ฒ  ๋ฐ ์•Œ๋ฃจ๋ฏธ๋Š„ ์Šคํ”ผ๋„ฌ ๊ตฌ์กฐ๋ฅผ ๊ฐ€์ง์„ ๋ณด์—ฌ ์ฃผ์—ˆ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜, NFA ์ด‰๋งค๋Š” NFX ์ด‰๋งค๋ณด๋‹ค ๋‚ฎ์€ ํ™˜์›์„ฑ์„ ๋ณด์˜€๋‹ค. ํ™˜์›๋œ NFA ์ด‰๋งค๋Š” ํ™˜์›๋œ NFX ์ด‰๋งค๋ณด๋‹ค ๋” ๋†’์€ ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์„ ๊ฐ€์ง„๋‹ค. ์•กํ™”์ฒœ์—ฐ๊ฐ€์Šค์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์—์„œ ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์ด ๋” ๋†’์€ NFA ์ด‰๋งค๋Š” NFX ์ด‰๋งค๋ณด๋‹ค ์šฐ์ˆ˜ํ•œ ๋ฐ˜์‘ํ™œ์„ฑ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ์ƒ์ดํ•œ ๋ถ•์†Œ/๋‹ˆ์ผˆ ๋ชฐ๋น„ (x = 0-1)๋ฅผ ๊ฐ–๋Š” ์ผ๋ จ์˜ ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ ๋‹ˆ์ผˆ-๋ถ•์†Œ-์•Œ๋ฃจ๋ฏธ๋‚˜ ์ œ๋กœ์ ค (x-NBA) ์ด‰๋งค๋ฅผ ์—ํญ์‚ฌ์ด๋“œ๊ธฐ๋ฐ˜ ์กธ-๊ฒ”๋ฒ•์œผ๋กœ ์ œ์กฐํ•˜์˜€๋‹ค. ๋‹ˆ์ผˆ-๋ถ•์†Œ-์•Œ๋ฃจ๋ฏธ๋‚˜ ์ œ๋กœ์ ค ์ด‰๋งค์˜ ๋ฐ˜์‘ํ™œ์„ฑ ๋ฐ ๋ฌผ๋ฆฌํ™”ํ•™์ ํŠน์„ฑ์— ๋Œ€ํ•œ ๋ถ•์†Œ/๋‹ˆ์ผˆ ๋ชฐ๋น„์— ๋”ฐ๋ฅธ ์˜ํ–ฅ์„ ์กฐ์‚ฌํ–ˆ๋‹ค. ๋ชจ๋“  ์ค‘ํ˜•๊ธฐ๊ณต์„ฑ x-NBA ์ด‰๋งค๋Š” ์œ ์‚ฌํ•œ ํ‘œ๋ฉด์ ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ๋ถ•์†Œ์˜ ๋„์ž…์€ ๋‹ˆ์ผˆ๊ณผ ๋‹ด์ฒด ์‚ฌ์ด์˜ ์ƒํ˜ธ ์ž‘์šฉ์„ ์ฆ๊ฐ€์‹œ์ผฐ๋‹ค. ๋˜ํ•œ, x-NBA ์ด‰๋งค์—์„œ ๋ถ•์†Œ์˜ ๋„์ž…์€ ๋ฉ”ํƒ„ ํ™œ์„ฑํ™” ์—๋„ˆ์ง€๋ฅผ ๊ฐ์†Œ์‹œํ‚ค๊ณ  ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์„ ์ฆ๊ฐ€์‹œํ‚ค๋Š” ๊ฒƒ์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ๋ถ•์†Œ ์กฐ์ด‰๋งค๋กœ ์ธํ•ด ๋ฉ”ํƒ„ ํก์ฐฉ๋Ÿ‰ ์ฆ๊ฐ€ ๋ฐ ๋‹ˆ์ผˆํ‘œ๋ฉด์ ์˜ ์ฆ๊ฐ€๋กœ ์ธํ•ด ์ด‰๋งค ํ™œ์„ฑ์— ๊ธ์ •์ ์ธ ์˜ํ–ฅ์„ ๋ฏธ์ณค๋‹ค. ๋ฉ”ํƒ„ ํก์ฐฉ๋Ÿ‰ ๋ฐ ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์˜ ์–‘์€ ๋ถ•์†Œ/๋‹ˆ์ผˆ ๋ชฐ๋น„์— ๋Œ€ํ•œ ํ™”์‚ฐํ˜• ๊ฒฝํ–ฅ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ๋ฉ”ํƒ„ ํก์ฐฉ๋Ÿ‰์ด ์ฆ๊ฐ€ํ•˜๊ณ  ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ LNG ์ „ํ™˜์œจ ๋ฐ ์ˆ˜์†Œ ์ˆ˜์œจ์€ ์„ ํ˜•์ ์œผ๋กœ ์ฆ๊ฐ€ํ–ˆ๋‹ค. ์ด‰๋งค ์ค‘์—์„œ ๊ฐ€์žฅ ๋งŽ์€ ์–‘์˜ ๋ฉ”ํƒ„ ํก์ฐฉ๋Ÿ‰๊ณผ ๊ฐ€์žฅ ๋†’์€ ๋‹ˆ์ผˆ ํ‘œ๋ฉด์ ์„ ๊ฐ€์ง„ 0.3-NBA๊ฐ€ ์ตœ๊ณ ์˜ ์ด‰๋งค ์„ฑ๋Šฅ์„ ๋ณด์—ฌ์ฃผ์—ˆ๋‹ค. ๋˜ํ•œ x-NBA ์ด‰๋งค๋Š” ์ฆ๊ธฐ ๊ฐœ์งˆ ๋ฐ˜์‘ ๋™์•ˆ ๊ฐ•ํ•œ ํƒ„์†Œ ์ €ํ•ญ์„ฑ์„ ๋‚˜ํƒ€๋ƒˆ๋‹ค. ์š”์•ฝํ•˜์ž๋ฉด, ๋‹ค์–‘ํ•œ ๋ฐฉ์‹์œผ๋กœ ๋ฌผ๋ฆฌํ™”ํ•™์ ์œผ๋กœ ๊ฐœ์„ ๋œ ๋‹ˆ์ผˆ-์•Œ๋ฃจ๋ฏธ๋‚˜ ์ด‰๋งค๋ฅผ ์ œ์กฐํ–ˆ์œผ๋ฉฐ LNG์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์— ์ ์šฉ๋˜์—ˆ๋‹ค. LNG์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์—์„œ ์ œ์กฐ๋œ ์ด‰๋งค์˜ ์ด‰๋งค ์„ฑ๋Šฅ์„ ์„ค๋ช…ํ•˜๊ธฐ ์œ„ํ•ด N2 ํกํƒˆ์ฐฉ๋ถ„์„, XRD, TPR, TEM, H2-TPD ๋ฐ CH4-TPD ๋ถ„์„๊ณผ ๊ฐ™์€ ๋ช‡ ๊ฐ€์ง€ ํŠน์„ฑ๋ถ„์„์„ ์ˆ˜ํ–‰ํ–ˆ๋‹ค. ์ด‰๋งค์˜ ๋‹ˆ์ผˆ๋ถ„์‚ฐ๋„ ๋ฐ ๋ฐ˜์‘๋ฌผ ์นœํ™”๋„๋Š” LNG์˜ ์ˆ˜์ฆ๊ธฐ๊ฐœ์งˆ๋ฐ˜์‘์— ์žˆ์–ด์„œ ์ด‰๋งค ์„ฑ๋Šฅ์„ ๊ฒฐ์ •ํ•˜๋Š” ์ค‘์š”ํ•œ ์š”์†Œ๋กœ ์ž‘์šฉํ•œ๋‹ค๊ณ  ๊ฒฐ๋ก ์ง€์„ ์ˆ˜ ์žˆ๋‹ค.Renewable energies are considered as clean energy sources, and optimal use of these resources minimizes environmental impact. Hydrogen has attracted much attention as the most promising energy carrier because it is clean and does not emit any pollutants such as NOx and SOx during the combustion. High energy density of hydrogen is another advantage of hydrogen utilization. These characteristics of hydrogen lead to a development of several hydrogen-related products such as hydrogen vehicle, combustion engine, and fuel cell. Several catalytic reforming processes for commercial hydrogen production from hydrocarbons have been extensively investigated, including steam reforming, partial oxidation, auto-thermal reforming, and dry reforming. Among these reforming processes, steam reforming has been widely employed for hydrogen production due to its high economical advantage. Moreover, liquefied natural gas (LNG), which is abundant and mainly composed of methane, can be used as a primary source for hydrogen production by steam reforming reaction. As LNG pipelines are more widespread in the modern cities, therefore, LNG will become an important hydrogen source for fuel cell system equipped with fuel processing unit. In this respect, it is necessary to research the high efficient chemical process of steam reforming of LNG. Nickel-based catalyst has been considered as the most feasible catalyst for steam reforming reactions due to its high intrinsic activity and low price. Conventional steam reforming reaction has been carried out at high reaction temperature (> 800 oC), high reaction pressure (> 20 bar), and high steam to carbon ratio (steam/carbon > 2) in order to achieve a maximum catalytic performance of nickel-based catalyst. However, such severe reaction conditions are not favorable for on-site hydrogen production due to safety problems. For this reason, developing an efficient steam reforming catalyst with high catalytic activity and durability at moderate reaction conditions is of great importance. It has been reported that well-developed mesoporous structure of nickel-alumina catalyst not only enhanced the dispersion of active nickel site on the alumina support, but also facilitated the heat/mass transfer over the catalyst, resulting in a high catalytic performance. Thus, mesoporous nickel-alumina catalysts have received much attention for improving both catalytic activity and stability in the reforming reactions. In this work, in order to derive high hydrogen production efficiency in the catalytic steam reforming of LNG, mesoporous nickel-alumina catalysts were physicochemically modified by various preparation methods, including epoxide-driven sol-gel method, supercritical CO2 drying method. Also nickel-alumina catalysts were promoted with iron or boron. First of all, a set of mesoporous nickel-iron-alumina xerogel catalysts (denoted as 20NixFeAl) with different iron loading (x = 0-10) were prepared by an epoxide-driven sol-gel method. The effect of iron loading on the physicochemical properties and catalytic activities of mesoporous nickel-iron-alumina xerogel catalysts in the steam reforming of liquefied natural gas was investigated. It was found that all the calcined 20NixFeAl catalysts showed a well-developed mesoporous structure and retained finely dispersed nickel and iron species. Reducibility of calcined 20NixFeAl catalysts was enhanced by iron addition due to the increased amount of octa-coordinated nickel species. From H2-TPD and XPS results, it was revealed that nickel surface area of reduced 20NixFeAl catalysts showed a volcano-shaped trend with respect to iron loading. This result indicates that an optimal iron addition was required for fine dispersion of nickel species in the reduced 20NixFeAl catalysts. In the steam reforming of LNG, 20Ni4FeAl catalyst with the highest nickel surface area showed the best catalytic performance in terms of LNG conversion and hydrogen yield. Thus, nickel surface area of 20NixFeAl catalysts played a key role in determining the catalytic performance in the steam reforming of LNG. A mesoporous nickel-iron-alumina aerogel (denoted as NFA) catalyst was prepared by a single-step epoxide-driven sol-gel method and a subsequent supercritical CO2 drying method. For comparison, a mesoporous nickel-iron-alumina xerogel (denoted as NFX) catalyst was also prepared by a single-step epoxide-driven sol-gel method and a subsequent evaporative drying method. Both catalysts were applied to the steam reforming of liquefied natural gas for hydrogen production. The effect of drying method on the physicochemical properties and catalytic activities of the catalysts was investigated. It was revealed that supercritical CO2 drying method was effective for enhancing textural properties of NFA catalyst. XRD and TPR results showed that both catalysts had nickel, iron, and aluminum spinel structures. However, NFA catalyst retained stronger metal-support interaction than NFX catalyst. It was also observed that the reduced NFA catalyst exhibited higher nickel surface area than the reduced NFX catalyst. In the hydrogen production by steam reforming of liquefied natural gas, NFA catalyst with higher nickel surface area showed a better catalytic performance than NFX catalyst. A series of mesoporous nickel-boron-alumina xerogel (x-NBA) catalysts with different boron/nickel molar ratio (x = 0-1) were prepared by an epoxide-driven sol-gel method. The effect of boron/nickel molar ratio on the catalytic activities and physicochemical properties of nickel-boron-alumina xerogel catalysts was investigated in the steam reforming of liquefied natural gas. All the mesoporous x-NBA catalysts showed similar surface area. Introduction of boron increased interaction between nickel and support. In addition, introduction of boron into x-NBA catalysts reduced methane activation energy and increased nickel surface area. Promotion of boron had a positive effect on the catalytic activity due to the increase of adsorbed methane and nickel surface area. The amount of adsorbed methane and nickel surface area exhibited volcano-shaped trends with respect to boron/nickel molar ratio. LNG conversion and hydrogen yield increased with increasing the amount of adsorbed methane and with increasing nickel surface area. Among the catalysts, 0.3-NBA, which retained the largest amount of adsorbed methane and the highest nickel surface area, showed the best catalytic performance. It was also revealed that x-NBA catalysts showed strong coke resistance during the steam reforming reaction. In summary, various physicochemically-improved nickel-alumina catalysts were prepared and they were applied to the hydrogen production by steam reforming of LNG in this study. In order to explain catalytic performance of the prepared catalysts in the steam reforming of LNG, several characterizations such as N2 adsorption-desorption, XRD, TPR, TEM, H2-TPD, and CH4-TPD analyses were carried out. It was concluded that nickel dispersion and reactant affinity of the catalysts played as an important factors determining the catalytic performance in the hydrogen production by steam reforming of LNG.Chapter 1. Introduction 1 1.1. Hydrogen production and utilization 1 1.2. Steam reforming reaction 9 1.3. Objective 14 Chapter 2. Experimental 17 2.1. Preparation of catalysts 17 2.1.1. Preparation of mesoporous nickel-iron-alumina xerogel catalyst by a single-step epoxide-driven sol-gel method 17 2.1.2. Preparation of mesoporous nickel-iron-alumina aerogel catalyst by a supercritical CO2 drying method 19 2.1.3. Preparation of mesoporous nickel-boron-alumina xerogel catalyst by a single-step epoxide-driven sol-gel method 21 2.2. Characterization 22 2.2.1. Physicochemical properties 22 2.2.2. Crystalline structure 22 2.2.3. Chemical states of elements 23 2.2.4. Reducibility 23 2.2.5. Morphological feature 23 2.2.6. H2 and CH4 adsorption studies on reduced catalysts 24 2.2.7. Carbon deposition on used catalysts 25 2.3. Hydrogen production by steam reforming of LNG 26 Chapter 3. Results and Discussion 29 3.1. Mesoporous nickel-iron-alumina xerogel catalyst prepared by a single-step epoxide-driven sol-gel method 29 3.1.1. Textural properties of calcined catalysts 29 3.1.2. Crystalline structures of calcined catalysts 32 3.1.3. Reducibility of calcined catalysts 34 3.1.4. Characterization of reduced catalysts 37 3.1.5. Catalytic performance in the steam reforming of LNG 44 3.2. Mesoporous nickel-iron-alumina aerogel catalyst prepared by a supercritical CO2 drying method 50 3.2.1. Physicochemical properties of catalysts 50 3.2.2. Characterization of calcined catalysts 53 3.2.3. Characterization of reduced catalysts 57 3.2.4. Catalytic performance in the steam reforming of LNG 65 3.3. Mesoporous nickel-boron-alumina xerogel catalyst prepared by a single-step epoxide-driven sol-gel method 67 3.3.1. Physicochemical properties of calcined catalysts 67 3.3.2. Crystalline structures of calcined catalysts 70 3.3.3. Reducibility of calcined catalysts 72 3.3.4. Methane adsorption capacity of reduced catalysts 74 3.3.5. Nickel surface area of reduced catalysts 78 3.3.6. Catalytic performance in the steam reforming of LNG 82 3.3.7. Characterization of used catalysts 86 Chapter 4. Conclusions 89 Bibliography 93 ์ดˆ ๋ก 102Docto
    corecore