순환유동층 재순환부 내 고체흐름 특성에 대한 시스템 압력의 영향

김성원; 김상돈; Sung Won Kim; Sang Done Kim

Korean Chemical Engineering Research, Vol.48, No.2, 198-204, April, 2010

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순환유동층 재순환부 내 고체흐름 특성에 대한 시스템 압력의 영향

Effect of Pressure on Solids Flow Characteristics in Recycle System of a Circulating Fluidized Bed

김성원^†, 김상돈

한국과학기술원 생명화학공학과, 305-701 대전시 유성구 구성동 373-1

Sung Won Kim^†, and Sang Done Kim

Department of Chemical & Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea

E-mail:

초록

가압순환유동층 적용을 위해 루프씰(loop-seal: 내경 0.10 m)을 갖는 고체재순환부(직경 0.10 m, 높이 2.25 m)에서 층 물질로 silica sand 입자(dp=240 μm, ρs=2582 kg/m3)를 사용하여 시스템 압력 변화(0.10~0.71 MPa)에 따른 고체흐름 특성을 연구하였다. 루프씰을 통한 고체질량플럭스는 공기주입량이 증가할수록 선형적으로 증가하였고, 동일한 공기주입속도에 대해 시스템 압력이 증가할수록 증가하였다. downcomer 내 압력변이는 시스템 압력이 증가할수록 동일한 공기주입속도에 대해 증가하였고, 흐름 내 고체속도 및 기체 속도 또한 증가하였다. 고체질량플럭스로부터 downcomer에서의 압력변이를 예측할 수 있는 상관관계식을 Transportation number와 Pressure drop number를 이용하여 제안하였다. 루프씰에서의 압력강하는 시스템 압력에 관계없이 고체질량플럭스가 증가할수록 증가하였다. 각각의 시스템 압력에서 공기주입속도 변화에 따른 고체질량플럭스 및 Transportation number를 예측할 수 있는 상관관계식을 제안하였다.

Solids flow characteristics have been determined in a pressurized solids recycle systems of silica sand particles for the application in a pressurized CFB(PCFB). The solids recycle system is composed of a downcomer(0.10 m i.d. 2.25 m high) and a loop-seal(0.10 m i.d.). The silica sand(dp=240 μm, ρs=2,582 kg/m3) particles were transported at room temperature and system pressure(Psys) up to 0.71 MPa using air. Solids mass flux(Gs) increases with increasing system pressure at constant aeration rate. Pressure gradient, solids velocity and actual gas velocity increase with increasing Psys at constant aeration rate. The Pressure drop number(Φ) on pressure gradient in downcomer has been correlated with Transportation number(Tr). Pressure drop across the loop-seal increases with increasing of Gs irrespective of variation of Psys. The obtained Gs and Transportation number(Tr) have been correlated with the experimental variables.

Keywords:Circulating Fluidized Bed;Solids Recycle System;Loop-Seal;System Pressure

[References]

Lee SH, Lee JM, Kim JS, Chol JH, Kim SD, HWAHAK KONGHAK, 38(4), 516 (2000)
Mann MD, Knutson RZ, Erjavec J, Jacobsen JP, Fuel, 83, 1643 (2004)
Knowlton TM, “Pressure and Temperature Effects in Fluid-Particle Systems,” Fluidization VII, eds. by Potter OE, Nicklin DJ, Engineering Foundation, New York, 27-46 (1992)
Beer JM, Prog. Energy Combust. Sci., 33, 107 (2007)
Kim SW, Namkung W, Kim SD, Chem. Eng. Technol., 24(8), 843 (2001)
Lee YY, Circulating Fluidized Beds, eds. by Grace JR, Avidan AA, Knowlton TM, Blackie Academic and Professional, London, UK, 417-440 (1997)
Kim SW, “Solids Recycle and Heat Transfer Characteristics in a Pressurized Circulating fluidized bed System,” PhD Disseration, KAIST (2002)
Merrow E, Chemical Engineering Processing, May, 14-22 (1985)
Cheng LM, Basu P, Powder Technol., 103(3), 203 (1999)
Geldart D, Powder Technol., 7, 285 (1973)
Wen CY, Yu YH, AIChE J., 12, 610 (1966)
Li J, Kuipers JAM, “Effect of Pressure on Flow Behaviors in Dense Gas-Fluidized Beds: A Discrete Particle Simulation Study,” Fluidization X, eds. by Kwauk M, Li J, Yang W, United Engineering Foundation, New York, 389-396 (2001)
Kim SW, Kim SD, Powder Technol., 124, 76 (2001)
Kim SW, Namkung W, Kim SD, Korean J. Chem. Eng., 16(1), 82 (1999)
Knowlton TM, AIChE Symp. Series, 93, 1 (1997)
Geldart D, Jones P, Powder Technol., 67, 163 (1991)
Wirth KE, “Fluid Mechanics of the Downcomer in Circulating Fluidized Beds,” Fluidization VIII, eds. by Large J, Laguerie C, Engineering Foundation, New York, 105-112 (1996)

[Related Articles]

[1] Lee SH, Lee JM, Kim JS, Chol JH, Kim SD, HWAHAK KONGHAK, 38(4), 516 (2000)

[2] Mann MD, Knutson RZ, Erjavec J, Jacobsen JP, Fuel, 83, 1643 (2004)

[3] Knowlton TM, “Pressure and Temperature Effects in Fluid-Particle Systems,” Fluidization VII, eds. by Potter OE, Nicklin DJ, Engineering Foundation, New York, 27-46 (1992)

[4] Beer JM, Prog. Energy Combust. Sci., 33, 107 (2007)

[5] Kim SW, Namkung W, Kim SD, Chem. Eng. Technol., 24(8), 843 (2001)

[6] Lee YY, Circulating Fluidized Beds, eds. by Grace JR, Avidan AA, Knowlton TM, Blackie Academic and Professional, London, UK, 417-440 (1997)

[7] Kim SW, “Solids Recycle and Heat Transfer Characteristics in a Pressurized Circulating fluidized bed System,” PhD Disseration, KAIST (2002)

[8] Merrow E, Chemical Engineering Processing, May, 14-22 (1985)

[9] Cheng LM, Basu P, Powder Technol., 103(3), 203 (1999)

[10] Geldart D, Powder Technol., 7, 285 (1973)

[11] Wen CY, Yu YH, AIChE J., 12, 610 (1966)

[12] Li J, Kuipers JAM, “Effect of Pressure on Flow Behaviors in Dense Gas-Fluidized Beds: A Discrete Particle Simulation Study,” Fluidization X, eds. by Kwauk M, Li J, Yang W, United Engineering Foundation, New York, 389-396 (2001)

[13] Kim SW, Kim SD, Powder Technol., 124, 76 (2001)

[14] Kim SW, Namkung W, Kim SD, Korean J. Chem. Eng., 16(1), 82 (1999)

[15] Knowlton TM, AIChE Symp. Series, 93, 1 (1997)

[16] Geldart D, Jones P, Powder Technol., 67, 163 (1991)

[17] Wirth KE, “Fluid Mechanics of the Downcomer in Circulating Fluidized Beds,” Fluidization VIII, eds. by Large J, Laguerie C, Engineering Foundation, New York, 105-112 (1996)