(563g) Advanced Optical Fiber Probe Technique to Measure Local Liquid Saturation and Velocity within Various Commercial Catalyst Shapes in Pilot Plant Trickle Bed Reactors (TBRs)

Advanced Two-Tip
Optical Fiber Probe Technique to Measure Local Gas and Liquid Saturations and
Velocities within Various Commercial Catalyst Shapes in Pilot Plant Trickle Bed
Reactors (TBRs).

Mohammed Al-Ani^a,
Muthanna H. Al-Dahhan^ab

a  Chemical and
Biochemical Engineering Department, Missouri University of Science and
Technology, Rolla MO 65409, USA

b
Mining and Nuclear Engineering Department, Missouri University of Science and
Technology, Rolla, MO 65409, USA

Email: aldahhanm@mat.edu

Trickle bed reactors (TBRs) have been widely used in
multiple commercial processes with different design and operation conditions
such as chemical industries (e.g., Petroleum petrochemical, chemical processes,
etc…). Trickle bed reactors are packed beds of catalyst particles with
concurrent downward of gas and liquid. Broadly, trickle bed reactors are used
in various industrial fields due to simplicity in operation under high
temperature and high-pressure conditions require for most industrial processes,
low energy consumption due to the solids are not suspended. However, the
disadvantages of trickle bed reactors are rapid deactivation and the
possibility for liquid maldistribution, which may be the reason for formation
hot spots and runaway the reactors due to excessive temperature and pressure in
the reactor.

Local liquid saturation investigation in multiphase
flow rectors can play a significant role on different critical parameters in
the reactor (pressure drop, a residence time of the liquid phase, axial
dispersion coefficient and heat transfer coefficient, etc.). Local liquid
saturation measuring and mapping at different bed height axially and
diametrical profile radially with varies operating conditions such as gas and
liquid flow rates, bed characteristics (shape and size), and physical
properties of fluids flow is essential for design and scale up and scale down
engineering to evaluate fundamental information in the reactor.

Advanced two-tip optical fiber probe
(OFP) technique was manufactured and developed in Multiphase Flow Reactor
Engineering and Application Laboratory (MFReal) in Missouri University of
Science and Technology. The main concept for OFP is based on the variation in
the light reflection that encountered at the probe tip by gas and liquid in the
reactor. Gases revealed higher reflection for the light than liquids. The
difference in the light reflection between the gas and liquid enables to measure
the local gas and liquid volume fraction locally. OFP has been implemented to
study important hydrodynamics in various multiphase flow reactors systems
successfully. Also, the high capability was revealed by measuring a diametrical
profile along bed height axially. The obtained data by OFP were validated with
the data obtained using x-ray digital industrial radiography (DIR) and syringe
pump techniques. The results have been indicated a high capability and
reliability for OFP to measure dynamic flow parameters (local gas and liquid
saturation and velocities).

Moreover, some other parameters such as local gas and
liquid velocities and evaluating channeling or bypassing locally along bed
height are also capable of being measured by processing different concepts. Successfully,
OFP used to study the effects of bed height, gas flow rate, liquid flow rate,
and catalyst shape (using different industrial catalyst shapes such as trilobe,
quadralobe, cylindrical, and spherical particles) on the liquid saturation and
local gas and liquid velocities diametrical profiles studied to evaluate
performance in the pilot plant trickle bed reactor.