We Solve Powder Flow Problems Mechanisms of Segregation Brought to you by: Material Flow Solutions, Inc. 7010 NW 23 rd Way, Suite A Gainesville, FL 32653

We Solve Powder Flow Problems

Mechanismsof Segregation

Brought to you by:

Material Flow Solutions, Inc.7010 NW 23rd Way, Suite A

Gainesville, FL 32653

An Interactive Learning Experience

www.matflowsol.com (352) 379-8879© Material Flow Solutions

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With over 30 years experience solving bulk powder and granule handling problems,Dr. Kerry Johanson is the industry leader and acknowledged world expert on segregation

Introducing Your Instructor

Dr. Kerry Johanson began his career in powder flow and material handling as a summer lab technician with Jenike & Johanson in Billerica, Massachusetts during his high school and undergraduate years. After receiving his BS in 1985, he spent 14 years with JR Johanson, Inc. in San Luis Obispo California, finally serving as their Chief Technical Officer. He received his Ph.D. in chemical engineering from Brigham Young University in 1994 and in 2000, he branched out and moved to Florida, where he divides his time researching at the University of Florida Particle Engineering Research Center and serving as the Chief Operations Officer for Material Flow Solutions, Inc., the consulting firm he founded in 2001. He has authored 40+ technical papers which have been published in numerous technical journals internationally. He has developed a course for teaching powder flow and technology to graduate students and mentored five doctoral graduates at the University of Florida. Dr. Johanson has presented numerous industry seminars on the topic of powder flow in industrial


applications. Married for 31 years, he is the father of six children, and a grandfather to four. He holds the rank of Eagle Scout with the Boy Scouts of America, and continues to serve as a Scout leader in his community. Dr. Johanson holds PE licenses in both Florida and Utah and is an active member of AAPS, AIChE, ASME, and ASTM.

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A Brief Introduction to SegregationIn its simplest form, Segregation is defined as the separation of various components in a mixture. The Segregation Potential of a bulk material is a measured value of the specific material’s tendency to separate under a set of specific conditions. Predicting a material’s potential for segregation is directly correlated to measuring the flow properties of the mixture as a whole, as well as the key flow properties of individual mixture components.


Steak Seasoning – note the bands of material that indicate segregation

materials separate, or segregate, during the manufacturing process, product quality is compromised. The net result is wasted product as well as significant plant down-time while the segregation issues are resolved.

Bird Seed Mix – note the separation of differently sized seeds in the pile

Virtually every manufactured product you have ever purchased or consumed has depended on proper mixing or blending of various raw materials during the manufacturing process. When the raw

Segregation, or separation, of granular and powder materials is one of the three main causes of process failure with systems that handle powder materials. It is a global problem, affecting all industries, and conservative estimates suggest that 30% of all unscheduled downtimes are due to segregation and the resultant quality issues.

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A Brief Introduction to SegregationMost manufactured products today are mixtures of several components. Generally, the individual ingredients in a mixture separate (segregate) during the manufacturing process, resulting in inconsistent final product.


To address and solve mixture segregation issues, it is critical to identify the root cause of the segregation problem. Segregating materials prevent otherwise viable products from coming to market and/or lower customer acceptance so products already in the market place become undesirable.

The Bottom Line: Lost Revenue

?No matter the root cause of segregation problems in industrial processes, the end result is often a box of Lucky Charms® with too many (or too few) marsh-mallow hearts – an Advil® caplet with too much (or too little) ibuprofen content – a box of Tide® with too much (or not enough) color-safe bleach particles. Each results in customer dissatisfaction and loss of company revenue.

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Pink Lemonade in the process hopper


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Impact Fluidization Segregation

Air Entrainment Segregation

Angle of Repose

Segregation

Sifting Segregation


A Brief Introduction to SegregationIn this interactive Power Point presentation, we will discuss the four most prominent mechanisms (or causes) of material segregation and the most effective method of measuring for segregation potential. These segregation mechanisms are:



? ? ?Coarse

Fines

?


PLAY

Sifting SegregationActual Product

The first mechanism of segregation is sifting. With SIFTING SEGREGATION, fine particles sift down through a matrix or grid of coarse particles causing separation of components in the mix. This produces a net increase in concentration of fine particles near the center of the pile. Sifting can result from any process that produces piles during filling or creates inter-particle motion, provided the particle size difference of the ingredients, or components, in the mixture is great enough. Sifting may also occur with any material that has a 3 to 1 difference in particle size and is free-flowing.


Schematic:Sifting Segregation


Coarse

Fines


PLAY

Angle of Repose SegregationActual Product

in repose angle and is moderately free-flowing. Angle of repose is the slope of the pile formed when that pile of material is at rest. More angularly shaped particles have a steeper angle of repose and fall (concentrate) near the center of the pile. More spherically shaped particles, with a flatter angle of repose, roll toward the edges of the pile or wall of the hopper. With angle of repose segregation, particles of different shapes and sizes form piles of different slopes during filling or emptying of process equipment. The material with the lower repose angle forms a flatter pile and occupies the region at the base of a pile, while the more frictional material concentrates near the center or top of the pile.

The individual angle of repose of each ingredient in a mixture has the potential to become a contributing factor in product segregation. ANGLE of REPOSE SEGREGATION can happen in any system that produces piles during filling or discharge. This segregation mechanism may occur with any material that has differences


Schematic:Angle of Repose

Segregation



Air Entrainment Segregation

PLAY

Actual ProductFor AIR ENTRAINMENT SEGREGATION to occur, there must be a source of air as the material enters process equipment. With air entrainment segregation, air is entrained (caught up) with the falling stream of particles. This air dislodges fine particles from the particle stream as it impacts the free surface of material and flows down the inverted conical slope formed by the particles in the process equipment. The increasing area of the flow path causes the air velocity to decrease, allowing fine particles to settle out of the entrained air flow and deposit on the pile, usually near the edge. Although air in a process system is generally caused by material free fall, pneumatic conveying systems can also produce air. When the aerated material stream impacts on a surface, the material consolidates and forces any entrained air out of the voids between particles, creating a net air flow down the pile. This air flow carries fine particles to the outer edges of the bin or process vessel.


Schematic:Air Entrainment

Segregation



Impact Fluidization Segregation

PLAY

Actual Product

IMPACT FLUIDIZATION SEGREGATION occurs when the material in the process equipment is in a semi-fluidized state and coarse, heavy particles impact on the surface of this fluffy material, penetrating the fluidized layer and resulting in layered segregation patterns. The local fluidization at the top material surface may be due to an air source in the process equipment or just the air escaping from the material during the filling process.


Schematic:Impact Fluidization

Segregation



Good BlendSegregation

Checking Your Understanding

Is this mixture of fine and coarse ingredients a good blend, or does it show segregation?


TRY AGAIN


This material is obviously segregating. The pattern formed by heavy concentration of fine particles down the center of the pile and coarser particles along the hopper wall is a classic example of sifting segregation.

Correct Answer: Segregation







Is this detergent mixture a good blend, or does it show segregation?

TRY AGAIN


Correct Answer: Good Blend

This sample is well-blended. The concentration of small blue particles is fairly uniform throughout.







Is this mixture of fine and coarse ingredients a good blend, or does it show segregation?

TRY AGAIN


This material is also very obviously segregating. The pattern formed by heavy concentration of finer particles at the bottom of the pile and coarser particles near the top of the pile, with very little blending, is a good example of impact fluidization segregation.








Is this mixture of fine white and coarse blue particles a good blend, or does it show segregation?

TRY AGAIN

We Solve Powder Flow Problemswww.matflowsol.com (352) 379-8879© Material Flow Solutions


Again, this material is very obviously segregating. The sample is a cross-cut segment of a larger pile. The pattern formed by heavy concentration of finer white particles down the center of the pile and coarser blue particles along the hopper wall is another example of sifting segregation.






Is this mixture of several fine, white pharmaceutical ingredients a good blend, or does it show segregation?

TRY AGAIN



When multiple ingredients of similar color are combined to form a mixture, it is difficult to tell simply through visual observation if segregation is occurring. In this instance, a methodology besides simple visual observation is required to accurately predict segregation potential.






Is this mixture of red and blue particles a good blend, or does it show segregation?

TRY AGAIN



When two ingredients of significantly different concentration levels are combined to form a mixture, it is difficult to tell simply through visual observation if segregation is occurring. Again, in this instance, a methodology besides simple visual observation is required to accurately predict segregation potential.






Is this steak seasoning mixture of multiple spices of varying shapes and sizes a good blend, or does it show segregation?

TRY AGAIN


Correct Answer: Good Blend

You may be surprised to find that this material is a good blend. At first glance, this does not appear to be the case. This is because, as we have previously discovered, visual observation is NOT a reliable method of measuring segregation. Let’s take a closer look at the last two samples.



Segregation Measurement Relies on Sample Size


Note the white circles marking various locations in these mixtures. Each circle represents a sample of the same size.


Over-all, the mixture of red and blue particles appears to be fairly well blended. However, from sample to sample taken from this mixture, the relative concentration of red particles to blue particles differs significantly, indicating undesirable segregation within the mixture.

Sample one contains significantly more red particles than does

Sample two

A Closer Look at the Make-up of Material Samples


2

1

Click to enlarge


In this next material, a spice blend, note that the white circles represent samples similar in volume, compared to quantity of the overall mixture, to those from the red and blue material. In this spice blend, the concentration of each ingredient is consistent from sample to sample.

A Closer Look at the Make-up of Material Samples

Both samples contain similar concentrations of each

ingredient in the mixture 1

2


Click to enlarge

1 21

2



Segregation Measurement Relies on Sample Size

Samples are collected either at strategic locations through the process or at a single pro-cess location, but at time intervals throughout a material run. Previously, industry had two methods of acquiring segregation data from material samples.

?The second method: Outsourcing testing to busy laboratories. This process generally entails waiting two, four, or more weeks for results. The gathered data is then manually analyzed and extrapolated by the engineers.

The first method: In house, they can send the sample to a testing lab that will hand-sift through a series of sieves collecting the variously sized particles and counting them. More sophisticated labs may have a mechanical sieve. Either method requires multiple samples that take hours each to analyze.

?LOST TIME = MONEY LOST


Visual Observation is Not a Reliable Method of Measuring Segregation. The Only Truly Reliable Method of Quantifying Product Segregation is Direct Measurement of the Mixture.

#1 Rule of Measuring Segregation

Laboratory chemical analysis and traditional – time consuming – sieving analysis takes hours, days or WEEKS

to acquire sufficient data Click the button to proceed

The Bottom Line: Lost RevenueREMEMBER:



Fastest – Most Accurate Tool for Measuring Segregation

Just as every individual carries a unique thumbprint, every particle emits a unique light spectra reflectance signature. The spectrometer inside the SPECTester measures the individual light reflectance spectra signature of each component or ingredient in the mixture. It then reads the light spectra signature of the entire mixture sample, identifying the presence, pattern and concentration of the individual components throughout the mixture. The presence of various components in unexpected locations or amounts within the mixture identifies the problem: SEGREGATION. The pattern created by the various mixture ingredients as the pile is formed in the tester identifies thecause, or mechanism, of that segregation. The concen-tration of the various components in specific locations within the pile identifies the magnitude of that segregation – how badly each ingredient separates from the mixture as a whole. The SPECTester reports these results in the form of tables, graphs and unit-less intensity numbers for both individual component segregation potential and overall product uniformity. All data produced can be saved and/or downloaded in Excel-ready format.

How Does it Work?



Fastest – Most Accurate Tool for Measuring Segregation

User-friendly data entry Identifies the unique spectral print of each ingredient

Graphically reports segregation profile of each ingredient

Numerically reports segregation intensity of each ingredient


FAST – 10 to 30 minutes to run an analysis. Measures a mixture of up to 6 unique components Identifies primary segregation mechanism out of 4

specific mechanisms Identifies segregation by particle size, sifting,

fluidization, angle of repose, chemical component, and air entrainment

Provides data about component concentration, particle size differences, product uniformity

Identifies process design parameters and quality control issues

Results scalable to process conditions – mimics actual process conditions

50 segregation points measured within a sample Fully automated, reports how much as well as why

the material mixture is segregating Provides uniformity index for sample, and

segregation variance data Data can be exported in Excel-ready format Certified CE Compliant


The SPECTester

Features


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Interactive PowerPoint Informative and Useful

Email: [email protected] Phone Line: 352-379-8879Direct to instructor: 352-303-9123

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We Solve Powder Flow Problems Mechanisms of Segregation Brought to you by: Material Flow Solutions, Inc. 7010 NW 23 rd Way, Suite A Gainesville, FL 32653