Here is a TimeLine of the PSRI History.


June 4, 2019

Dispersion Model Used to Capture Hydrodynamics in a Fluidized Bed with Internals

PSRI has quantify gas backmixing behavior in fluidized beds with and without bed internals using Helium gas tracer using an advection-diffusion transport equations. The presence of the tube bundles reduced the amount of lateral mixing resulting in a more plug flow behavior and an increase in the Peclet number or number of CSTRs. As an example, for a first order reactions the fluidized bed with the tube bundle resulted in a 18% higher reaction rate than the fluidized bed without the tube bundles.\n
February 4, 2019

Population Balance Model Developed to Predict and Troubleshoot Attrition Issues

PSRI has developed a population balance model (PBM) for attrition prediction in fluidized beds. The model tracks the shrinkage via diameter reduction of the particles due to rates of abrasion and fragmentation. The fragmentation is also a function of the breakage model and is integrated for that particles size to all smaller particle sizes.
September 25, 2018

PSRI Develops an Operators Training Program for Fluidized Beds and Circulating Fluidized Beds

PSRI has developed a new training course and workshop focusing on operating and problem solving fluidized beds and circulating fluidized beds. This three-day course includes training on large cold-flow equipment.

PSRI Demonstrates How Submerging a Trickle Valve Can Reduce Gas Leakages

Immersing the cyclone into the fluidized bed several feet or one meter, resulted in decreasing the gas flowing up the dipleg by 50%. Presumably, the mechanism for this is the “viscosity” of the emulsion in the fluidized bed is high enough to limit the seepage of gas through the trickle valve when immersed in a fluidized bed.

PSRI Demonstrates How Vortex Stabilizers Mitigate Trickle Valve Gas Leakages

Trickle valves have the potential to have higher gas leakage up the dipleg, because the particles are at the bottom of the trickle valve and the gas is at the top. As a trickle valve erodes, which is usually at the top, gas from the freeboard can leak through the trickle valve unopposed by solids. Have a cyclone with a vortex stabilizer can significantly reduce this leakage.

Dr. Ben Freireich is PSRI's Technical Director

Dr. Ben Freireich joins as PSRI's Technical Director

Dr. S.B. Reddy Karri Advances to Consulting Director

Dr. Reddy Karri moved from his role as Technical Director at PSRI to Consulting Director. He will be responsible for expanding PSRI's consulting role with member companies ...

Role of Internals on Fluidized Bed Hydrodynamics

Fluidized bed internals can significantly lower the operating bed density as well as reduce the dynamic pressure on those internals. The presences of internals increases the bubble volume fraction as a result of higher bubble frequencies, smaller bubble sizes and slower bubble velocities.

Vortex Stabilizer Can Mitigate the Effects of Poor Trickle Valve Operations

PSRI discovers that a vortex stabilizer can re-introduce the upflow of solids from a leaky trickle valve back to the cyclone wall thereby mitigating the impact a poor trickle valve can have on cyclone operations.

Influence of Trickle Valve performance on Cyclone Efficiency

PSRI quantifies how leakage from a trickle valve can be the controlling factor on a cyclone's collection efficiency. A leaky trickle valve can impose upward gas flows in the dipleg of more than 3 to 4 ft/sec. This results in a significant injection of fines into the inner vortex of the cyclone which results in much lower collection efficiencies.

A New 3-ft (0.9-m)-Diameter Stripper

PSRI commissions a new 3-ft (0.9-m)-diameter by 25-ft (7.6-m) tall stripper fed with two risers to allow for solids fluxes of more than 25 lb/ft2-sec (125 kg/m2-sec).

Dynamic Force Sensors

PSRI develops dynamic force sensors for quantifying dynamic and static forces on fluidized bed internals such as stripper elements and cooling coils.

PSRI Moves to its New Office Complex

December 15, 2013 PSRI moves into its new office complex.

PSRI Purchases 5 Acres of Property

PSRI purchases 5 acres of property that contained its existing research facility plus additional facilities for future expansion.

Fluorescent Solids Tracer Technique

PSRI develops its second generation fluorescent solids tracer technique that provides a 10X increase in the signal to noise ratio which now makes it useful not only in fluidized beds but also in strippers and risers.

Method for Using Accelerometers

PSRI develops a method for using accelerometers on the outside of cyclones and strippers for detecting the onset of flooding.

Liquid Injection into Fluidized Beds

PSRI, along with Syncrude, uses high speed video to discern the mechanism for particle coating and agglomeration by using liquid injection into a fluidized bed.

Advancing Standpipe Designs

PSRI uses CFD to confirm earlier work where protrusions may help with standpipe pressure build.

Using Acoustic to Detect Flooding in a Stripper

PSRI used inexpensive accelerometers on a stripper to detect flooding.

Particle Segregation in Risers

Segregation in the particle distributions based on size and density were evaluated in a riser for small and large glass beads and large polyethylene powder.

Cyclone Erosion

PSRI demonstrates how vortex stabilizers can reduce cone erosion in secondary cyclones.

Quantifying Clusters in a Riser

Using fiber optic probes and wavelet decomposition, PSRI and the University of Colorado measured cluster appearance, duration, and frequency in all parts of a riser for smaller and larger Geldart Group B material.

Office of President and CEO

July 1, 2010 - Ray A. Cocco became the President and CEO of PSRI, Inc.

Clusters and Streamers in Risers

PSRI and NETL quantify cluster behavior using high speed video analysis for the hydrodynamics in a riser.

Less Intrusive Fiber Optic Probes

PSRI uses CFD to confirm that fiber optic probes can be intrusive and that a shield may mitigate this effect.

New Technical Director

Dr. S.B. Reddy Karri became the new technical director of PSRI. He is a third technical director in the history of PSRI.

Granular Temperature in a Riser

PSRI and NETL use high-speed video and a modified borescope to quantify the granular temperature in a riser with FCC catalyst powder.

Visualized Particle Clusters In and Above the Fluidized Bed

Using a custom boroscope and high speed video camera, particle clusters are captured in and above a fluidized bed of polyethylene and FCC powder.

PSRI Round Robin Reveals Deficiency in PSD Measurements

PSRI performs a round robin with seven other companies. Most diffraction techniques are incapable of providing fines results for bimodal distributions with the exception of Sympatec.

New Jet Cup Design for Measuring Particle Attrition

PSRI confirms that existing jet cup attrition testing is insufficient. PSRI redesigns the jet cup to provide quantitative ordering of material with respect to attrition rates in a fast fluidized bed unit.

Fine Particles May Lower Entrainment Rates

PSRI documents how the addition of fines could actually lower the entrainment rate for fluidized beds.

Gas Bypassing in Fluidized Beds

Gas bypassing is documented for deep fluidized beds of Geldart Group A powders.

Analysis of Cyclone Flow Patterns

Cyclone operation is examined with respect to riser termination and solids loadings.

Core-Annulus Profile with Upflow or Downflow at the Walls

Flow regime maps for riser performance including regions where upflow or downflow is at the walls.

Streaming or Ribbon Flow in Diplegs

Design and operating specifications to prevent streaming flow in cyclone diplegs are developed.

Dipleg Splash Plate Design and Operation

Design criteria for open area is needed for trouble free dipleg operations with splash plates.

Design and Operating Specs for Trickle Valves

Design and operating specifications for trickle valves on secondary cyclones are developed.

Second PSRI Challenge Problem

Similar to the first challenge problem, validation data from 8” ID x 72’ riser is made available to the modeling community.

PSRI Develops Optical Fiber Probe for Solids Concentration

PSRI notes the nonlinear behavior of commonly used optical fiber probes. Redesigns probe to minimize this nonlinearity.


PSRI joins the Multiphase Fluid Dynamics Consortium (MFDRC), a five year program designed to better develop CFD codes for granular-fluid systems.

Design Specs for Feeding Standpipes

Design procedures are developed for standpipe configurations and the feeding of those standpipes.

PSRI Presents First Challenge Problem

In an effort to provide the modeling community with validation data, PSRI provides data for an 8” ID x 72’ riser with an L-valve configuration.

Gas-Solid Jet Penetration Correlations Developed

Jet penetration correlations modified for systems where solid particles are in the gas jets.

Choking and Saltation Velocity Correlations

Flow regimes are mapped. Correlations of choking and saltation velocities in dilute phase conveying is developed.

Design and Operation Procedures for Standpipes

Design specification and operating procedures, including aeration requirements, are developed for smooth standpipe operations for Geldart Group A and B powders.

Entrainment and Critical Gas Correlation Developed

A new correlation for predicting the entrainment rate above TDH is developed. It is based on the coordinate system which was used to correlate the choking-velocity data in dilute-phase pneumatic conveying. A more accurate correlation to predict the critical velocity is also developed.

Jet Penetration Correlations Developed

Correlations for gas jets in a fluidized bed with a upward, downward or horizontal configuration is developed.

Design and Operating Criteria for Dense Phase Conveying

Design and operating criteria is developed for dense phase conveying. Correlations for capacity is developed.

Core-Annulus Profile in Risers Revealed

PSRI confirms reports that a core-annulus profile in a large-scale riser can exist.

PSRI Moves to Chicago

IGT and IIT provide experimental facilities for PSRI. Ted M. Knowlton becomes Technical Director.

Cyclone Attrition

Power law model for particle attrition in cyclones.

Particle Classifier Devlopment

Evaluation of Bahco Microparticle Classifier and subsequent development of PSRI classifier.

Pressure Drop in Cyclone Correlation Developed

Pressure drop correlation based on inlet, acceleration, barrel friction, and deceleration effects is developed.

Aeration Requirements for Dilute Phase Pneumatic Conveying

Design specification for aeration of a dilute phase conveying line with respect to feeding and elbows is developed.

Development of Gas Distribution Requirements

Design specifications for hole and pressure drop requirements to ensure good fluidization is developed.

Formation of PSRI

A consortium consisting of 9 companies is formed to address better understanding in particle technology. Fred Zenz is the Technical Director.