DEM Modelling of Vibratory Screens
Doktorsavhandling, 2021

In Sweden, about 100 million tons of aggregate is used for road, railway, and concrete every year. Crushing is the main process for producing aggregate material in different fractions. The production process is divided into two sub-processes: comminution or size reduction and classification. The vibratory screen is one of the separation machines used to make a final separation to produce the products based on a grade or a size range. In an industry where logistics plays an important role, the transport of unnecessary materials can be costly and it is therefore critical to screen these materials before transporting them. Industrial vibratory screens are costly and also have a substantial effect on the quality of the final product. Therefore, selecting the correct vibratory screen for the crushing plant at the outset results in a better return on investment and better quality products.

The main aim of this research is to understand the screening process in different conditions such as different particle size distribution (PSD) and different feed rates. The first step towards achieving the screening model is to understand the influence of different machine parameters and material properties in the screening performance. Some of these parameters have been studied in this research, such as the motion type, the material of the screen media, and the aperture shape. The Discrete Element Method (DEM) has been used to study these parameters with the idea that by using DEM simulation the particle-to-particle and particle-to-geometry interaction can be studied in a way that is impossible to achieve by real experiments.

The study results show that some of the factors have a greater influence on screening, such as the effect of the motion type for the different slope of the deck. Elliptical motion is more efficient compared to linear motion. Also, the aperture shape in different parts of the screen deck has a different effect when using a single-layer or multi-layer material in the feeding point. The result of this research needs further investigation to study the effect of the interaction between different factors before achieving the complete screen model. Another achievement of this research work is to investigate the validation of DEM modelling in screening performance by using a laboratory-scale vibratory screen.

Validation

Modelling

Screen efficiency

DEM simulation

Virtual Development Laboratory (VDL), Hörsalsvägen 7A, 412 58, Göteborg and Via Zoom (Password: 586970)
Opponent: Dr. Peter Radziszewski

Författare

Ali Davoodi

Chalmers, Industri- och materialvetenskap, Produktutveckling

What is trending today? Of course, it is sustainability in society concerning the resources we consume as humans. One such resource is aggregates and minerals products, which is the foundation of infrastructure development. Looking at the statistics, the consumption of aggregates in Sweden is about 100 million tons every year, consisting of approximately 90% crushed rock.

To produce aggregates, the rock material needs to be crushed and screened in different stages, which are often high energy-consuming processes. One way to minimize energy consumption is to improve production efficiency. This can be done by analyzing data from the operation and using different simulation platforms to improve equipment utilization.

One of the main classification processes applied in the industry is screening with vibratory screens. A vibratory screen’s main functionality is particle separation, which is a function of gravity, the properties of the granular material, equipment geometry, and the screen’s relative motion. Discrete Element Method (DEM) has been used to study particle behaviour and it is a suitable tool for studying the screening performance. The particle-to-particle and particle-to-geometry interaction can be studied using DEM in a way that is impossible to achieve with physical experiments.

By using DEM simulation, the fundamental understanding of how to improve screening efficiency can be expanded. The advantage of using simulations instead of experiments to improve screening performance is minimizing cost and energy consumption which is one step toward sustainability. Another advantage is that DEM simulations provide practical feedback when designing the vibratory screen. This allows the designer to determine the correctness and efficiency of a design before the screen is constructed.

Ämneskategorier

Maskinteknik

Drivkrafter

Hållbar utveckling

Styrkeområden

Produktion

ISBN

978-91-7905-451-9

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4918

Utgivare

Chalmers tekniska högskola

Virtual Development Laboratory (VDL), Hörsalsvägen 7A, 412 58, Göteborg and Via Zoom (Password: 586970)

Online

Opponent: Dr. Peter Radziszewski

Mer information

Senast uppdaterat

2021-02-25