Growth of gas jet at the distributor plate of a fluidized bed

Conference · Fri May 01 04:00:00 EDT 1981

OSTI ID:5766167

Li, C T

Characterization of the gas jetting phenomenon at the distributor region is important to the design of a fluidized-bed reactor. A new gas-jet-growing model has been proposed based on a material balance of gas flowing through a jet. The model predicts the length of gas jets, the frequency of formation of jets (or initial bubbles), as well as several other jet characteristics. To develop the new gas jet growing model the following assumptions were made: (1) The flame like jet formed at the distributor consists geometrically of a reversed cone at the bottom and a paraboloidal cap at the top. The shape of a typical gas jet is shown in Figure 1. (2) The velocity of gas leaking through the gas jet-dense phase boundary is equal to U/sub f/ or U/sub mf/epsilon/sub mf. (3) When there is no significant pulsating motion of particles around the orifice, gas jet grows from zero to a maximum stable size. At the maximum all the gas supplied to the jet through the orifice is equal to the amount which leaks from the jet to the dense phase. (4) In a bubbling fluidized bed, gas jets detach from the distributor before they reach their maximum size. The premature detachment of jets is due to the instable condition created by the churning and pulsating motions of particles around the orifice. (5) The volume of the initial bubble formed above the distributor is equal to that of the gas jet detached from the distributor.

• Research Organization: Pacific Northwest Lab., Richland, WA (USA)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 5766167
• Report Number(s): PNL-SA-9568; CONF-810581-4; ON: DE83014637
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000* -- Coal
Lignite
& Peat-- Combustion
BUBBLES
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
COAL
COMBUSTION
COMBUSTORS
DESIGN
ENERGY SOURCES
FLUIDIZED-BED COMBUSTION
FLUIDIZED-BED COMBUSTORS
FOSSIL FUELS
FUELS
JETS
MATERIALS
MATHEMATICAL MODELS
OXIDATION
PULSATIONS
THERMOCHEMICAL PROCESSES