Experimental Study on Gas-Solid Mass Transfer in Circulating Fluidized Beds

Abstract

Abstract: This study is devoted to gas-solid mass transfer behavior in heterogeneous two-phase flow.
Experiments were carried out in a cold circulating fluidized bed of 3.0 m in height and 72
mm in diameter with naphthalene particles. Axial and radial distributions of sublimated
naphthalene concentration in air were measured with an online concentration monitoring
system HP GC-MS. Mass transfer coefficients were obtained under various operating
conditions, showing that heterogeneous flow structure strongly influences the axial and
radial profiles of mass transfer coefficients. In the bottom dense region, mass transfer
rate is high due to intensive dynamic behavior and higher relative slip velocity between
gas and clusters. In the middle transition region and the upper dilute region, as a result
of low mass transfer driving force and the influence of flow structure, mass transfer rate
distribution becomes non-uniform. In conclusion, among the operating parameters influencing
mass transfer coefficients, the superficial gas velocity is the most important factor and
the solid circulation rate should be also taken into account.

Key words: mass transfer, circulating fluidized bed, gas-solid heterogeneous flow

摘要： This study is devoted to gas-solid mass transfer behavior in heterogeneous two-phase flow.
Experiments were carried out in a cold circulating fluidized bed of 3.0 m in height and 72
mm in diameter with naphthalene particles. Axial and radial distributions of sublimated
naphthalene concentration in air were measured with an online concentration monitoring
system HP GC-MS. Mass transfer coefficients were obtained under various operating
conditions, showing that heterogeneous flow structure strongly influences the axial and
radial profiles of mass transfer coefficients. In the bottom dense region, mass transfer
rate is high due to intensive dynamic behavior and higher relative slip velocity between
gas and clusters. In the middle transition region and the upper dilute region, as a result
of low mass transfer driving force and the influence of flow structure, mass transfer rate
distribution becomes non-uniform. In conclusion, among the operating parameters influencing
mass transfer coefficients, the superficial gas velocity is the most important factor and
the solid circulation rate should be also taken into account.

关键词: mass transfer;circulating fluidized bed;gas-solid heterogeneous flow

WANG Linna, ZHANG Ling, JIN Dongjie, LI Jinghai. Experimental Study on Gas-Solid Mass Transfer in Circulating Fluidized Beds[J]. .

王琳娜, 张苓, 靳东杰, 李静海. 循环流化床气固传质实验研究[J]. CIESC Journal.

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