Peter Wypych

• Professor at University of Wollongong

Predicting the performance of finely atomized sprays used for airborne dust suppression is an important aspect in ensuring workers are properly protected from harmful dust emissions in the industries that rely on bulk materials handling and processing. It is well known that finely atomized sprays are effective for airborne dust capture, however the...

Dust generation and dispersion continue to be a major concern for many in the industries that rely on bulk materials handling, and the ability to predict dust generation and dispersion remains challenging. This study looks at the use of computational fluid dynamics (CFD) and discrete element method (DEM) as a means of predicting dust generation and...

The over-arching objective for this project was to develop 'dustless' mining operations in the key areas of the longwall and the development face. To achieve this, the project was split into two phases; The first phase focusing on the longwall and the second phase looking at the development face. The project relied on the application and investigat...

Dust emissions in the industries that rely on bulk handling are very common, from mines to port terminals and also within plants and factories. They are generally harmful to human health, can affect production and also cause material waste. In the past, many techniques have been applied to control dust emissions, including water spraying systems, w...

The re-emergence of coal workers pneumoconiosis since 2015 has prompted the coal industry to reassess current measures for the monitoring and control of dust in their operations. A recent project funded by the Australian coal industry (ACARP) has focused on quantifying, modelling, and controlling (through suppression) typical dust generating events...

Fluidized dense-phase pneumatic conveying of powders has a number of benefits in various industries such as coal-fired thermal power plants, chemical, cement, pharmaceutical, petrochemical plants, etc. However, reliable designing of fluidized dense phase pneumatic conveying system is significantly difficult due to the complex and turbulent nature o...

The coal industry faces significant challenges in the control of dust to meet emissions regulations and goals as well as ensuring sustainable operations. This paper describes some of the different techniques and innovative technologies that are being developed and implemented to improve the suppression of airborne dust, specifically through the use...

Currently there is very little information available on how variables such as crosswind can affect the performance of dust suppression sprays. This paper outlines work completed on measuring, characterising and predicting the performance of high-energy micro-mist sprays under crosswind conditions. Overall results show reasonable agreement between t...

Respirable dust exposure has long been known to be a serious health threat. In Australia, the threat of Coal Workers Pneumoconiosis (CWP) was thought to be eradicated from the industry, however, in the period 2015-2017 there were over 30 confirmed cases. The re-emergence of CWP has prompted industry wide investigations into improving dust control t...

Fluidized dense-phase pneumatic conveying of powders is gaining popularity in several industries, such as power, chemical, cement, refinery, alumina, pharmaceutical, limestone, because of reduced gas flow rate and power consumption, decreased conveying velocities, improved product quality control, reduced pipeline sizing and wear rate, increased wo...

The coal industry faces significant challenges in the control of dust to meet emissions regulations and goals as well as ensuring sustainable operations. This paper describes some of the different techniques and innovative technologies that are being developed and implemented to improve the suppression of airborne dust, specifically through the use...

An Experimental Investigation into the flowability of Pharmaceutical Powders.

Dust generation occurs in many bulk material handling processes, including; during free fall, transport hubs of handling of bulk materials, granular material loading or unloading and impact on conveyor transfers or other materials. Dust can pose an air pollution problem in; communities, the environment, industry equipment and be hazardous to health...

Pneumatic transport of fine powders in fluidized dense-phase mode is becoming increasingly popular in various industries, such as power, chemical, cement, refinery, alumina, pharmaceutical, limestone, to list a few, because of the reasons of reduced gas flow rate and power consumption, decreased conveying velocities, improved product quality contro...

Dust generation during bulk material handling, free fall and impact on conveyor transfers can pose an effect on human health, communities, environment, industry equipment and is also an air pollutant. Dustiness testers are one method which can be used to quantify dust generation. This paper investigates the two computational techniques available to...

Dust generation forms a large part of the challenges that bulk materials handling engineers face throughout the life of their career. Dust generation can lead to health problems, explosion risks, material segregation and environment pollution [1-5]. These conditions are typical of run of mine dump hoppers, grain silos, coal train dump stations and...

The bulk materials handling industry faces significant challenges in the control of dust to ensure continued sustainable operation and to meet emissions regulations and goals. With Australia's industry emissions of particulate matter below 10 μm increasing from 530 million kilograms in 2009/2010 to 920 million kilograms in 2013/2014 [1] the problem...

Dustiness testers are used to quantify the level of dust within a bulk material. The generation of dust can occur as a result of many bulk materials handling activities, including; filling or discharge from storage bins, during free-fall, material impact on conveyor transfers or impact with other materials. Dust generation can have a serious impact...

Results are presented of an ongoing investigation into modeling friction in fluidized dense-phase pneumatic transport of bulk solids. Many popular modeling methods of the solids friction use the dimen-sionless solids loading ratio and Froude number. When evaluated under proper scale-up conditions of pipe diameter and length, many of these models ha...

Fluidized dense-phase pneumatic conveying of powders is becoming increasingly popular in various industries, such as power, chemical, cement, refinery, alumina, pharmaceutical, limestone, to list a few, due to the reasons of reduced gas flows and power consumption, improved product quality control, reduced pipeline sizing and wear rate, increased w...

An accurate estimation of the total pressure drop of a pipeline is important to the reliable design of a pneumatic conveying system. The present paper presents results from an investigation into the modelling of the pressure drop at a bend in the pneumatic conveying of fly ash. Seven existing bend models were used (in conjunction with solids fricti...

The generation of dust occurs in many bulk materials handling applications, including during free-fall, material impact on conveyor transfers, or impact with other materials. Dust has potentially serious consequences to the surrounding environment as well as workers and nearby communities. Companies need to identify and quantify the dust being gene...

This paper presents results of an ongoing investigation into the flow mechanism for the pneumatic conveying of fine powders conveyed from fluidized dense phase mode to dilute-phase. Three different techniques of signal analysis (i.e. rescaled range analysis, phase space method and technique of Shannon entropy) have been applied to the pressure fluc...

For the reliable design of fluidized dense-phase pneumatic conveying systems, it is of paramount importance to accurately estimate blockage conditions or the minimum transport boundary. Existing empirical models for the fluidized dense-phase conveying of fine powders are either based on a limited number of products and pipelines or have not been te...

Pneumatic conveying is the process of transportation of dry bulk materials through pipelines with the help of air or other non-reacting gases. Under-prediction of minimum transport boundary (i.e. minimum conveying air requirement) would result in either reduced throughput or line blockage. An accurate estimation of the total pipeline pressure drop...

Abstract This paper presents results from an investigation into the changes in flow mechanism of pneumatic conveying of fine powders from dilute to fluidized dense-phase. Pressure fluctuations have been analyzed using power spectral density, Hilbert-Huang transformation and wavelet transformation. Pressure fluctuations were obtained from conveying...

Abstract This paper presents results from an investigation into the changes in flow mechanism of pneumatic conveying of fine powders from dilute to fluidized dense-phase. Pressure fluctuations have been analyzed using power spectral density, Hilbert-Huang transformation and wavelet transformation. Pressure fluctuations were obtained from conveying...

The aim of this paper is to investigate into flow mechanism with the help of pressure signal fluctuations analysis and modeling solids friction in case of solids–gas flows for fluidized-dense-phase pneumatic conveying of fine powders. Materials conveyed include fly ash (median particle diameter 30 µm; particle density 2300 kg m−3; loose-poured bulk...

This paper presents the results of an ongoing investigation into the fluctuations of pressure signals due to solids-gas flows for dense-phase pneumatic conveying of fine powders. Pressure signals were obtained from pressure transducers installed along different locations of a pipeline for the fluidized dense-phase pneumatic conveying of fly ash (me...

Fig. Predicted versus experimental PCC, fly ash, 69 mm I.D. × 168 m pipe, ms = 19 t/h.

This paper presents results of an ongoing investigation into modelling fluidized dense-phase pneumatic conveying of powders. For the reliable design of dense-phase pneumatic conveying systems, an accurate estimation of the blockage boundary condition or the minimum transport velocity requirement is of significant importance. The existing empirical...

This article presents results from an investigation into the pneumatic conveying characteristics (PCC) for horizontal straight-pipe sections for fluidized dense-phase pneumatic conveying of powders. Two fine powders (median particle diameter: 30 and 55 µm; particle density: 2300 and 1600 kg m−3; loose-poured bulk density: 700 and 620 kg m−3) were c...

Dust generation is a common result of many bulk handling and mining applications and has potentially serious consequences to the surrounding environment as well as workers and nearby community. Companies need to know how much and what type of dust is being generated so they can find ways to reduce this dust. Dustiness testers can be used for this p...

Modelling the interaction between particles and boundaries is of great interest and importance in many Discrete Element Method (DEM) applications where boundary failure conditions dictate the flow behaviour and velocity gradients of a bulk material. Bulk wall friction angles in DEM models are dependent on the mechanical properties of the particles...

The reliable design and operation of bulk materials handling and processing plants can be difficult when dealing with complex geometries and difficult-to-handle materials, such as wet and sticky ore. Often a lack of detailed analysis of bulk material flow and process boundary interactions can lead to costly mistakes which can typically be identifie...

This paper presents results of an investigation into the modeling of pressure drop in horizontal straight pipe section for fluidized dense-phase pneumatic conveying of powders. “Suspension density” and superficial air velocity have been used to model pressure drop for two-phase solids-gas flow. Two applicable models formats (developed by other rese...

Discrete element method (DEM) is a popular numerical method used to understand the discontinuous flow of granular materials and optimise the design and operation of equipment. The impingement of granular material on to flat surfaces can involve complex flow dynamics and can be difficult to model using analytical techniques. There are a vast number...

This article presents results of an ongoing effort toward improving the modeling and scale-up procedures for the dense-phase pneumatic conveying of fine powders through pipes. Two new approaches are employed in this study. One approach, derived by modifying an existing reliable dilute-phase model to make it suitable for the dense-phase, has resulte...

Conveyor transfer stations play a key role in many industries that handle bulk materials. Transfer stations can be rather sensitive to changes in material properties and can lead to relentless problems regarding reliability, wear, bottlenecking and blockages. Wet and sticky ores are typically difficult to handle materials due to their obnoxious abi...

Purpose - The purpose of this paper is to examine several calibration techniques that have been developed to determine the discrete element method (DEM) parameters for slow and rapid unconfined flow of granular conical pile formation. This paper also aims to discuss some of the methods currently employed to scale particle properties to reduce compu...

Discrete element method (DEM) is proving to be a reliable and increasingly used tool to study and predict the behaviour of granular materials. Numerous particle-scale mechanisms influence the bulk behaviour and flow of bulk materials. It is important that the relevant measurable input parameters for discrete element models be measured by laboratory...

A critical factor in the design of hood-spoon type conveyor transfers is to match the exit velocity of the material through a conveyor transfer to that of the conveyor belt receiving the material. If particle velocity increases too much issues such as particle attrition, dust generation, chute and belt wear and excessive noise can arise, whereas if...

Seven belt conveyor trajectory methods, C.E.M.A., M.H.E.A., Booth, Golka, Korzen, Goodyear, and Dunlop, are presented with their differences explained. Each method uses equations to determine the X and Y coordinates of the trajectory profile. Some methods also use graphical approaches, which allow a quicker determination of the trajectory. Methods...

This article presents results from an ongoing research effort aimed towards developing a validated scaleup procedure for pressure drop for the dense-phase pneumatic conveying of powders. Two existing/popular forms of the “system” approach for scaling up of diameter were evaluated. The validity of the current technique for length scaleup using a “sy...

This article presents results from an investigation into the modeling of solids friction factor for fluidized dense-phase pneumatic conveying of powders. A fundamental design approach was pursued by employing “straight pipe” and “back calculation” techniques for modeling and using two types of power function formats. The “straight pipe” models were...

A conveyor transfer research facility has been commissioned at the University of Wollongong to investigate particle flow mechanisms through conveyor transfers. As part of this research, investigations into conveyor trajectories have been undertaken at varying belt speeds and using two granular free-flowing materials. Numerous numerical methods exis...

This article results from an ongoing investigation aimed at developing a new validated test-design procedure for the accurate prediction of pressure drop for dense-phase pneumatic conveying of powders. Models for combined pressure drop coefficient (“K”) for solids-gas mixture were derived using the concept of “suspension density” by using the stead...

For the reliable design of pneumatic conveying systems, an accurate estimation of the minimum transport boundary is of significant importance. This paper presents results from an effort to establish a unified criterion for scaling-up the unstable boundary for the dense-phase pneumatic conveying of powders. An existing method of representing minimum...

A new theoretical air leakage model was developed for both conventional and high-pressure rotary valves. Different sizes of rotary valves (D = 250 and 300 mm) and a single-slit apparatus were tested over a wide range of conditions (N = 0 to 30 rpm; Δp v = 0 to 300 kPa; c = 0.10 to 0.25 mm). All the model predictions were found to be within ±6% of t...

Is this the year you'll install a new pneumatic conveying system in your plant? This article explains how a professional startup technician can supervise the system startup, ensure that the system runs smoothly, and train employees to run and troubleshoot the system with confidence.

This article presents three sensing methods developed for the nonintrusive monitoring of important flow parameters in dense-phase pneumatic conveying. With the optical measurement system, images of the flow are acquired and an image analysis is used to determine the sequence, length, and velocity of slugs for given materials and operating condition...

This article summarizes a research and development project that was undertaken to develop, design, and implement new pneumatic conveying technology for the safe and reliable handling of highly explosive metal powders. Some of the challenging process requirements and safety design principles that had to be adopted for this project also are described...

Researchers at the University of Wollongong conducted a study to provide industry with a validated modeling procedure for the accurate prediction of pressure drop and optimal operating conditions for fluidized dense-phase pneumatic conveying systems. Power function based models for solids were generated on a wide-range of steady-state straight pipe...

Powders and granulated solids are widely used in industrial bulk solids storage, handling, and transportation systems. Such bulk materials handling operations frequently involve a falling stream of material. During such a process, the surrounding air is induced to flow with the falling particle stream, forming a particle-driven plume. Herein, exper...

Capacitive measurement principles offer a non-invasive approach to determine particle velocity as well as particle concentration in pneumatic conveying. In order to assess the quality of a reconstruction method, it is mandatory to know the prevailing velocity and concentration profiles. For particulate bulk solids transportation, accurate reference...

This paper presents seven material discharge trajectory methods and explains the differences between them. Most of these methods involve a series of equations to determine first whether low-speed or high-speed conveying condition apply, then the material discharge angle for low-speed conditions and finally the X and Y coordinates of the trajectory...

This paper presents a review of the various methods available to predict the discharge angle of material as it leaves the head pulley of a conveyor belt. This discharge angle prediction is a vital component in the overall determination of the discharge trajectory of material and as a result will dictate the design of a transfer chute to adequately...

This paper presents results from an investigation into the modelling of solids friction factor for fluidised dense-phase pneumatic conveying of powders. A model generated by the authors (based on straight pipe data) and three other popular/applicable models (developed by other researchers) were initially evaluated to predict the total pipeline pres...

This paper is aimed at demonstrating the requirement of selecting a proper bend model for accurately estimating the total system pressure loss for the dilute and fluidised dense-phase pneumatic conveying of powders. Three popular/applicable bend models were used to predict the total pipeline pressure drop for pneumatically transporting power statio...

Industry widely uses rotary valves and blow tanks for the pneumatic conveying of products, each having their pros and cons depending on the specific application. This article shows the differing results obtained when low-velocity conveying a product through a common pipeline using both a drop-through rotary valve and a bottom-discharge blow tank fe...

This paper presents results from an investigation into power-function modelling of solids friction factor for the dilute-phase and fluidised dense-phase (FDP) conveying of powders. Three different diameters/lengths of pipeline were used to generate a wide range of steady-state data and also explore important scale-up issues. The effect of pressure...

The guidelines for handling bulk solid such as powders, pellets, and granules are presented. The materials that initially have uniform composition may change during handling, such as if segregation occurs, the material may demonstrate different bulk properties. The product may also change with time, temperature, attrition, or through natural degrad...

This paper presents results from investigations into quantifying and modelling the dust generation and air entrainment mechanisms that occur during free-falling streams of material. Emphasis is placed on the effects of drop height and product temperature. This information is important for the efficient design and operation of dust control systems,...

This paper describes a study of free falling streams of particles or "particle plumes". Experiments in air were carried out to determine the volumetric flow rate of entrained air as a function of drop height, mass flow rate and particle properties. Flow visualisation observations of the particle plumes are presented that show how the stream of part...

In dense-phase pneumatic conveying, particles are transported along a pipeline at relatively low conveying speeds. Due to the relatively gentle handling characteristics of this mode of flow, it is suitable for conveying fragile and brittle bulk materials used in the food and chemical industries. The simulation of the stress field within a slug aims...

Successful pneumatic conveying of granular materials can be achieved only when: the air mass flow rate is controlled within a certain range; the pipe size is selected appropriately; and the operating boundaries are well assessed. This paper presents results from investigations into the capacity limitation of low-velocity slug-flow pneumatic conveyi...

The minimum transport or capacity limitation boundary for low-velocity slug-flow pneumatic conveying affects the design and operation of conveying systems. Unfortunately, the relevant mechanisms involved with this boundary still lack full understanding and assessment. Investigations have been carried out to model the capacity limitation for the low...

Many designers, operators, and even researchers often take the dilute-phase mode of transport for granted and overlook some of its unique characteristics and problems. This chapter describes some of these situations and also presents results that have been obtained in seeking appropriate solutions to particular problems. Dilute-phase pneumatic conv...

Most powders and dusts found in industry can explode when mixed with the right amount of oxidant. For a dust cloud to explode: dust must be explosible and airborne; dust cloud must be present in an atmosphere capable of supporting combustion and in contact with an ignition source of sufficient energy; size distribution of airborne particles must be...