(572c) Dilute Phase Riser Dynamics – a Comparison of Scale

2019 AIChE Annual Meeting

Topic/Group: Fluidization and Fluid-Particle Systems

Tentative Session: Circulating
Fluidized Beds

Title: Dilute
Phase Riser Dynamics – A Comparison of Scale

Authors:

Ronald W. Breault:          Ronald.Breault@netl.doe.gov

Steven L. Rowan:              Steven.Rowan@netl.doe.gov

Jingsi Yang:                         Jingi.Yang@netl.doe.gov

Justin Weber:                    Justin.Weber@netl.doe.gov

Key Words:
Fluidization, Circulating Fluidized Bed, Scaling, Cold Flow, Energy

Abstract:

Risers in gas-solids circulating
systems are used extensively in the petrochemical and energy industries as well
as being proposed for advanced technologies from chemical looping
combustion/gasification. The performance of these units has been linked to the
meso-scale and the dynamic behavior of the flow field.  To examine the effects of riser scale on
these dynamic behaviors, experimental data collected in a 0.1 m diameter riser
with a 5.3 m height is compared to data collected under similar operating
conditions in a 0.3m diameter riser with a 16m height. Experiments were
conducted primarily in the dilute upflow regime prior
to core-annular flow, with Gs/Gs* ratios between 0.2 and 0.3, and superficial
gas velocities ranging between 5.5 – 6.0 m/s. Comparisons between riser
pressure, solids fraction, voidage, and particle
velocity profiles are considered for a range of bed materials, including 750 µm
high density polyethylene (HDPE) and 180 µm glass beads.    Additionally, where available, three-dimensional
measurements of the solids volume fraction obtained via a Tech4Image Electrical
Capacitance Volume Tomography (ECVT) system are discussed.  The effect of system scale is analyzed and
discussed.