Book contents
- Frontmatter
- Contents
- Contributors
- Preface
- Common nomenclature
- 1 Introduction
- 2 Initiation of spouting
- 3 Empirical and analytical hydrodynamics
- 4 Computational fluid dynamic modeling of spouted beds
- 5 Conical spouted beds
- 6 Hydrodynamics of spout-fluid beds
- 7 Spouted and spout-fluid beds with draft tubes
- 8 Particle mixing and segregation
- 9 Heat and mass transfer
- 10 Powder–particle spouted beds
- 11 Drying of particulate solids
- 12 Drying of solutions, slurries, and pastes
- 13 Granulation and particle coating
- 14 The Wurster coater
- 15 Gasification, pyrolysis, and combustion
- 16 Spouted bed electrochemical reactors
- 17 Scaleup, slot-rectangular, and multiple spouting
- 18 Mechanical spouting
- 19 Catalytic reactors and their modeling
- 20 Liquid and liquid–gas spouting of solids
- Index
- References
5 - Conical spouted beds
Published online by Cambridge University Press: 04 February 2011
- Frontmatter
- Contents
- Contributors
- Preface
- Common nomenclature
- 1 Introduction
- 2 Initiation of spouting
- 3 Empirical and analytical hydrodynamics
- 4 Computational fluid dynamic modeling of spouted beds
- 5 Conical spouted beds
- 6 Hydrodynamics of spout-fluid beds
- 7 Spouted and spout-fluid beds with draft tubes
- 8 Particle mixing and segregation
- 9 Heat and mass transfer
- 10 Powder–particle spouted beds
- 11 Drying of particulate solids
- 12 Drying of solutions, slurries, and pastes
- 13 Granulation and particle coating
- 14 The Wurster coater
- 15 Gasification, pyrolysis, and combustion
- 16 Spouted bed electrochemical reactors
- 17 Scaleup, slot-rectangular, and multiple spouting
- 18 Mechanical spouting
- 19 Catalytic reactors and their modeling
- 20 Liquid and liquid–gas spouting of solids
- Index
- References
Summary
Introduction
In spite of the versatility of spouted beds of conventional geometry (cylindrical with conical base), there are situations in which the gas–solid contact is not fully satisfactory. In these situations, the process conditioning factors are the physical characteristics of the solid and the residence time of the gas. Thus, conical spouted beds have been used for drying suspensions, solutions, and pasty materials. Chemical reaction applications, such as catalytic polymerization, coal gasification, and waste pyrolysis, have also been under research and development.
In fast reactions, such as ultrapyrolysis, selectivity is the factor that conditions the design, so the optimum residence time of the gaseous phase can be as short as a few milliseconds. The spouting in conical beds attains these gas residence times, which can be controlled within a narrow range. Nevertheless, until the 1990s, the literature on the principles and hydrodynamics of the flow regimes in conical spouted beds was very scarce, and its diffusion was very limited, partially owing to the scant dissemination in the past of the research on such beds carried out in Eastern Europe.
Conditions for stable operation and design geometric factors
Operating in conical contactors is sensitive to the geometry of the contactor and to particle diameter, so it is necessary to delimit the operating conditions that strictly correspond to the spouted bed regime and allow for the gas–solid contact to take place stably.
- Type
- Chapter
- Information
- Spouted and Spout-Fluid BedsFundamentals and Applications, pp. 82 - 104Publisher: Cambridge University PressPrint publication year: 2010
References
- 1
- Cited by