Distinctive Hydrodynamics of a Micro Fluidized Bed and Its Application to Gas–Solid Reaction Analysis

Abstract

The measurement and analysis of reaction behavior, kinetics quantification, and mechanism clarification for gas–solid reactions are essential to the research and development of process technologies in fields of chemical engineering, energy production, mineral processing, etc. By far, different approaches and instruments have been applied for gas–solid reaction analysis and measurement, but a recent development appears distinctive because of its use of a micro fluidized bed (MFB) in implementing the so-called isothermal differential analysis of gas–solid reactions at the Institute of Process Engineering, Chinese Academy of Sciences (CAS). Systematic work has been reported on hydrodynamic studies in MFBs and the standardized development as well as its utilization of the so-called micro fluidized bed reaction analyzer (MFBRA) for investigating various particle-involved reactions, such as pyrolysis, combustion, gasification, reduction, catalysis, absorption, etc. The obtained results well demonstrated the distinctiveness of MFBs from the common large-size fluidized beds and the obvious advantages of the MFBRA for reaction analysis in aspects of rapid heating of the reactant sample, minimization of diffusion limitation to the reaction, real-time online capture of isothermal product formation characteristics, etc. It was shown that MFBRA is particularly capable of analyzing rapid complex reactions and providing some exceptional functions, such as steam atmosphere, online particle sampling, and decoupling of complex reactions in series. A series of applications well verified that the MFBRA provides actually a fundamental approach and the kind of instruments that are complementary to those of thermogravimetric analysis (TGA) for gas–solid reaction measurement and analysis.

Kinetic Study on Continuous Sampling of Coal Char from a Micro Fluidized Bed

“… 30 , 31 Xu et al used an MFB to measure several kinds of gas–solid reactions. 32 , 33 All these studies show very good reliability of the MFB for investigating gas–solid reactions.…”

Solid Circulating Velocity Measurement in a Liquid–Solid Micro-Circulating Fluidised Bed

“…Micro-fluidised beds refer to fluidised bed with the bed inner diameter or cross-section at the millimetre scale [5][6][7][8] and find possible applications in a microfluidics and micro-technology context [9][10][11]. These types of bed are considered to be a promising way of achieving high quality fluid and solid mixing and process intensification of heat and mass transfer under a laminar flow regime and could potentially offer novel process opportunities [11][12][13].…”

Experimental methods in chemical engineering: Reactors—fluidized beds

“…Most of the work in fluidized beds is dedicated to pyrolysis, combustion, gasification, and reduction, which require adding solids to the bed as it operates . Transporting solids between the reaction and regeneration zones—circulating fluidized beds—is a common configuration to identify process conditions for scale up for coal combustion and to examine emissions, for example .…”