고속유동층에서의 기체혼합특성

남궁원; 김상돈

HWAHAK KONGHAK, Vol.36, No.5, 797-803, October, 1998

Export Citation

고속유동층에서의 기체혼합특성

Gas Mixing Characteristics in a Fast Fluidized Bed

남궁원, 김상돈

초록

고속유동층 반응기(직경 0.1m, 높이 5.3m)에서 층물질로 silica sand 입자를 사용하여 기상유속과 고체순환속도가 기체의 반경방향혼합 및 기체역혼합특성에 미치는 영향을 연구하였다. 반경방향의 기체분산계수(D_r)는 고체체류량이 증가할수록 증가하였다. 반경방향의 분산계수(D_r)에 대한 상관식을 Froude number와 무차원군을 사용하여 제시하였다. 벽면 근처에서는 입자의 하강흐름으로 인하여 상당한 양의 기체역혼합이 관찰되었지만, 중심영역에서는 기-고의 높은 상승흐름으로 인하여 기체의역혼합은 크게 감소하였다. Peclet number의 항으로 기체역혼합계수에 대한 상관식을 무차원군을 사용하여 제시하였다

The effects of gas velocity and solid circulation rate on the radial gas mixing and backmixing characteristics have been determined in a fast fluidized bed(0.1m- I.D.X5.3m-high). Radial gas mixing coefficient(D_r) increases with increasing solid holdup. Radial gas mixing coefficient has been correlated with the Froude number and the pertinent dimensionless groups. The considerable amount of backmixed tracer gas near the wall region is observed due to the downflow of solids. However, at the center region of the bed, gas backmixing is negligibly small due to high upward flow of gas-solid mixture. Gas backmixing coefficient in terms of Peclet number has been correlated with the dimensionless groups.

Keywords:Fast Fluidized Bed;Radial Gas Mixing;Gas Backmixing

[References]

Li Y, Wu P, "Circulating Fluidized Bed Technol. III," eds. by Basu, P., Horio, M. and Hasatani, M., Pergamon Press, 581 (1991)
Cankurt NT, Yerushalmi J, "Fluidization," eds. by Davidson, J.F. and Keairns, D.L., Cambridge Univ. Press, 387 (1978)
Brereton CMH, Grace JR, Yu J, "Circulating Fluidized Bed Technol. II," eds. by Basu, P. and Large, J.F., Pergamon Press, 307 (1988)
Li J, Weinstein H, Chem. Eng. Sci., 44, 1697 (1989)
Werther J, Hartge EU, Kruse M, Powder Technol., 70, 293 (1992)
Amos G, Rhodes MJ, Mineo H, Chem. Eng. Sci., 48, 943 (1993)
Namkung W, Kim SD, "Circulating Fluidized Bed Technol. V," eds. by Kwauk, M. and Li, J., Science Press, Beijing, 134 (1997)
Yang G, Zhe H, Zhao L, "Fluidization IV," eds. by Kunii, D. and Toei, R., Engineering Foundation, 145 (1984)
Adams CK, "Circulating Fluidized Bed Technol. II," eds. by Basu, P. and Large, J.F., Pergamon Press, 299 (1988)
Martin MP, Turlior P, Bernard JR, Wild G, Powder Technol., 70, 249 (1992)
Namkung W, Cho YJ, Kim SD, HWAHAK KONGHAK, 32(2), 241 (1994)
Kim SW, Namkung W, Kim SD, Proc. of 10th Symposium on Chem. Eng. Taejon/Chungnam-Kyushu, 149 (1997)
Klinkenberg A, Krajenbrink HJ, Lauwerier HA, Ind. Eng. Chem., 45, 1202 (1953)
Tsuji Y, Morikawa Y, Shiomi H, J. Fluid Mech., 139, 417 (1984)
Gayan P, Dediego LF, Adanez J, Powder Technol., 94(2), 163 (1997)
Zheng Q, Wei X, Fei L, "Fluidization VII," eds. by Potter, O.E. and Nicklin, D.J., Engineering Foundation, 285 (1992)
Wei F, Jin Y, Yu ZQ, Liu JZ, Chem. Eng. Technol., 18(1), 59 (1995)
Bader R, Findlay J, Knowlton TM, "Circulating Fluidized Bed Technol. II," eds. by Basu, P. and Large, J.F., Pergamon Press, 123 (1988)
Nguyen HV, Potter OE, Dent DC, Whitehead AB, AIChE J., 27, 509 (1981)
Namkung W, Kim SD, Powder Technol., in press (1998)
Hetsroni G, Int. J. Multiph. Flow, 15, 735 (1989)
Kagawa H, Mineo H, Yamazaki K, Yoshida K, "Circulating Fluidized Bed Technol. III," eds. by Basu, P., Horio, M. and Hasatani, M. 551 (1991)
Rhodes MJ, Wang XC, Cheng H, Hirama T, Gibbs BM, Chem. Eng. Sci., 47, 1635 (1992)
Schgerl K, Proc. of the Int. Symp. on Fluidization, eds. by Drinkenburg, A.A.M., 782 (1967)
Lee JS, Kim SD, HWAHAK KONGHAK, 20(3), 207 (1982)
Lee GS, Kim SD, Chem. Eng. Commun., 86, 91 (1989)

[Referenced By]

[1] Li Y, Wu P, "Circulating Fluidized Bed Technol. III," eds. by Basu, P., Horio, M. and Hasatani, M., Pergamon Press, 581 (1991)

[2] Cankurt NT, Yerushalmi J, "Fluidization," eds. by Davidson, J.F. and Keairns, D.L., Cambridge Univ. Press, 387 (1978)

[3] Brereton CMH, Grace JR, Yu J, "Circulating Fluidized Bed Technol. II," eds. by Basu, P. and Large, J.F., Pergamon Press, 307 (1988)

[4] Li J, Weinstein H, Chem. Eng. Sci., 44, 1697 (1989)

[5] Werther J, Hartge EU, Kruse M, Powder Technol., 70, 293 (1992)

[6] Amos G, Rhodes MJ, Mineo H, Chem. Eng. Sci., 48, 943 (1993)

[7] Namkung W, Kim SD, "Circulating Fluidized Bed Technol. V," eds. by Kwauk, M. and Li, J., Science Press, Beijing, 134 (1997)

[8] Yang G, Zhe H, Zhao L, "Fluidization IV," eds. by Kunii, D. and Toei, R., Engineering Foundation, 145 (1984)

[9] Adams CK, "Circulating Fluidized Bed Technol. II," eds. by Basu, P. and Large, J.F., Pergamon Press, 299 (1988)

[10] Martin MP, Turlior P, Bernard JR, Wild G, Powder Technol., 70, 249 (1992)

[11] Namkung W, Cho YJ, Kim SD, HWAHAK KONGHAK, 32(2), 241 (1994)

[12] Kim SW, Namkung W, Kim SD, Proc. of 10th Symposium on Chem. Eng. Taejon/Chungnam-Kyushu, 149 (1997)

[13] Klinkenberg A, Krajenbrink HJ, Lauwerier HA, Ind. Eng. Chem., 45, 1202 (1953)

[14] Tsuji Y, Morikawa Y, Shiomi H, J. Fluid Mech., 139, 417 (1984)

[15] Gayan P, Dediego LF, Adanez J, Powder Technol., 94(2), 163 (1997)

[16] Zheng Q, Wei X, Fei L, "Fluidization VII," eds. by Potter, O.E. and Nicklin, D.J., Engineering Foundation, 285 (1992)

[17] Wei F, Jin Y, Yu ZQ, Liu JZ, Chem. Eng. Technol., 18(1), 59 (1995)

[18] Bader R, Findlay J, Knowlton TM, "Circulating Fluidized Bed Technol. II," eds. by Basu, P. and Large, J.F., Pergamon Press, 123 (1988)

[19] Nguyen HV, Potter OE, Dent DC, Whitehead AB, AIChE J., 27, 509 (1981)

[20] Namkung W, Kim SD, Powder Technol., in press (1998)

[21] Hetsroni G, Int. J. Multiph. Flow, 15, 735 (1989)

[22] Kagawa H, Mineo H, Yamazaki K, Yoshida K, "Circulating Fluidized Bed Technol. III," eds. by Basu, P., Horio, M. and Hasatani, M. 551 (1991)

[23] Rhodes MJ, Wang XC, Cheng H, Hirama T, Gibbs BM, Chem. Eng. Sci., 47, 1635 (1992)

[24] Schgerl K, Proc. of the Int. Symp. on Fluidization, eds. by Drinkenburg, A.A.M., 782 (1967)

[25] Lee JS, Kim SD, HWAHAK KONGHAK, 20(3), 207 (1982)

[26] Lee GS, Kim SD, Chem. Eng. Commun., 86, 91 (1989)