Adding Process Equipment to the DPSIM Flowsheet

Our project now contains a defined material feed.

We know:

• how much solid enters the process;
• how much water enters;
• the particle size distribution;
• the solid components;
• the composition of each particle size class.

The next step is to define what happens to that material.

In DPSIM, process operations are represented by equipment objects placed on the flowsheet. Each equipment object is associated with a mathematical model that determines how its incoming material streams are transformed into its output streams.

In this tutorial, we will explore the DPSIM process model library and add our first process equipment to the flowsheet.

In this tutorial you will learn how to:

• understand the DPSIM equipment categories;
• distinguish the graphical equipment object from its process model;
• select a model from the toolbar;
• add equipment to the flowsheet;
• understand equipment input and output ports;
• organize and identify process units;
• choose an appropriate model for the objective of the simulation.

Figure 1. DPSIM toolbar with the main equipment categories highlighted.

The DPSIM process model library

The DPSIM Static Module organizes available models into six main categories:

Feed

Comminution

Classification

Concentration

Dewatering

Auxiliary

Figure 2. Toolbar showing Feed, Comminution, Classification, Concentration, Dewatering and Auxiliary.

Each category is divided into smaller groups according to the type of process operation.

For example, Comminution includes groups such as:

• Crushers;
• Mills;
• HPGR;
• Product size;
• Energy.

Classification includes:

• Screens;
• Hydrocyclones;
• Partition curves.

Concentration includes models for operations such as:

• Flotation;
• Separators;
• Gravity separation and other concentration methods, depending on the installed model set.

Dewatering includes operations such as:

• Thickeners;
• Filters.

And Auxiliary contains operations that support the construction of the flowsheet, including:

• Mixers;
• Splitters;
• Buffers;
• material handling models;
• other auxiliary functions.

Figure 3. Examples of two or three expanded equipment categories.

This organization makes it easier to find models according to their process function rather than searching through a single long list.

Equipment and mathematical models

An important concept in DPSIM is the relationship between the equipment shown on the flowsheet and the mathematical model behind it.

Consider a crusher.

On the flowsheet, the crusher appears as a graphical process unit:

Crusher icon

But the icon alone does not determine how the crusher behaves.

Its behavior comes from the mathematical model associated with that equipment instance.

For example, the DPSIM comminution library contains different crusher modeling approaches.

These models may use different parameters, assumptions and equations to predict the resulting product size distribution.

Figure 4. Two crusher model entries with similar process function but different model names.

Therefore:

Process equipment = graphical unit + mathematical model + parameters + ports

When you select a model from the DPSIM toolbar, DPSIM creates an equipment instance already associated with that model.

The model is not simply a visual label.

It is the calculation method that will be executed when the flowsheet is simulated.

Why more than one model may exist for the same process

There is rarely one universal mathematical model that is ideal for every mineral processing study.

Consider crushing.

One study may have detailed equipment and ore parameters available.

Another may only have a known product size distribution.

A preliminary study may require a relatively simple empirical representation, while a calibrated plant simulation may justify a more detailed model.

For this reason, DPSIM can contain several modeling approaches for the same general operation.

The same principle applies to:

• screens;
• hydrocyclones;
• grinding mills;
• flotation;
• separation;
• dewatering.

Figure 5. One process operation pointing to several possible mathematical models.

Engineering note

The most complex model is not automatically the best model.

A model should be selected according to:

the objective of the study

the available data

the required prediction

and

the validity range of the model

A sophisticated model with poorly estimated parameters may produce a less useful simulation than a simpler model supported by reliable data.

Exploring the Comminution category

Open:

Comminution

The available models are grouped by subcategory.

Figure 6. Comminution menu model groups.

Figure 6A. Comminution category opened from the DPSIM toolbar.

For example, the current DPSIM model library includes crusher models, simplified grinding mill models, an HPGR model and models based on specified product size or energy conditions.

The crusher group includes different modeling approaches rather than a single generic crusher.

The mill group likewise contains models for different grinding equipment.

At this stage, we do not need to understand the equations behind each model.

Individual model families will be covered later in this tutorial series.

For now, the important concept is:

selecting a library entry also selects the mathematical representation that DPSIM will use for that process unit.

Adding equipment to the flowsheet

Before selecting a model, click approximately where you want the equipment to appear on the flowsheet canvas.

Then open the appropriate equipment category and select the desired model.

For example:

Comminution → Crushers → [selected crusher model]

DPSIM creates the equipment at the selected location on the flowsheet.

Figure 7. Blank DPSIM canvas before placing process equipment.

Figure 8. Feed and crusher positioned in sequence before adding a material stream.

The new object is now part of the simulation project.

You can move it around the canvas to organize the flowsheet.

For the example we have been building throughout this series, position the crusher to the right of the feed:

Editable Feed → Crusher

Do not connect them yet.

We will create the material stream connections in the next tutorial.

Figure 9. Editable Feed and Crusher positioned beside each other but not connected.

Understanding equipment ports

When equipment is added to the flowsheet, it contains ports.

Ports define where material streams can enter or leave the equipment.

A simple unit may contain:

Feed port

and:

Product port

Figure 10. Simple equipment icon with Feed and Product ports identified.

An equipment model that produces two products may contain ports such as:

Feed

Oversize

Undersize

or:

Feed

Concentrate

Tail

depending on the operation.

Figure 11. Screen with Feed, Oversize and Undersize ports.

The names of the ports are important because they represent the physical meaning of each material connection.

A screen, for example, does not simply produce two anonymous output streams.

One output represents the coarse product and the other the fine product.

Likewise, a flotation model may distinguish concentrate and tailings.

These port definitions become important when constructing more complex flowsheets.

One input does not always mean one stream

Some equipment can receive material from more than one upstream source.

A mixer is an obvious example.

Several incoming streams can be combined into a single output stream.

Conceptually:

Stream A + Stream B → Mixer → Combined Stream

Figure 12. Mixer with multiple incoming streams and one output.

Other units may have multiple output ports.

For example:

Feed → Screen → Oversize + Undersize

or:

Feed → Separator → Concentrate + Tail

Figure 13. Examples of one-input/one-output and one-input/two-output equipment.

The process model defines what happens to the material between these ports.

Exploring the Classification category

Open:

Classification

The model library contains groups including:

Screens

Hydrocyclones

and:

Partition curves

Figure 14. Classification menu model groups.

Figure 14A. Classification category opened from the DPSIM toolbar.

The current library includes, among others, screen models such as Karra Screen and King Screen, as well as hydrocyclone and generic partition-curve approaches.

These models perform similar broad process functions — separating a particle population — but they do not necessarily calculate that separation in the same way.

A screen model may use equipment geometry and operating conditions.

A generic partition model may instead directly describe the probability of each particle size reporting to one product.

This illustrates why the model name matters.

Two icons representing classification equipment can correspond to fundamentally different mathematical assumptions.

Exploring Concentration and Dewatering

The Concentration category contains models that redistribute solid components between product streams.

Examples include flotation and component-recovery separators.

Figure 15. Concentration menu expanded.

These models can change not only total mass distribution but also the composition of the resulting products.

For example:

Feed → Separation → Concentrate + Tailings

The valuable component may preferentially report to the concentrate while gangue preferentially reports to the tailings.

The Dewatering category contains models such as thickeners and filters.

Figure 16. Dewatering menu expanded.

These operations primarily redistribute solids and water between their products.

For example:

Thickener Feed → Underflow + Overflow

or:

Filter Feed → Cake + Filtrate

The same component and size representation that we defined earlier continues through these operations.

Auxiliary equipment

Not every object in a process flowsheet represents a major mineral processing transformation.

Flowsheets also require operations such as:

• mixing streams;
• dividing streams;
• representing intermediate storage;
• transporting material;
• applying simplified process constraints.

These functions are available under:

Auxiliary

Figure 17. Auxiliary menu model groups.

Figure 17A. Auxiliary category opened from the DPSIM toolbar.

For example, a Mixer can combine several streams.

A Splitter can divide a stream between different process paths.

These units become particularly useful when constructing recycle circuits and more complex plant configurations.

Equipment icons are not the process model

The graphical icon helps communicate the flowsheet.

However, the icon should not be used to identify the model mathematically.

Two models may represent the same equipment family and therefore use similar or even identical graphical symbols.

Figure 18. Similar equipment icons with different model names underneath.

When reviewing a simulation, always consider:

What equipment is this?

and separately:

Which model is calculating its behavior?

This distinction becomes especially important when comparing different modeling approaches for the same plant.

For example, two simulation cases could have visually identical crusher flowsheets while using different crusher models.

Their predicted results may therefore be different.

Naming equipment clearly

As the flowsheet grows, clear equipment labels become increasingly important.

A flowsheet containing labels such as:

Crusher 1

Crusher 2

Screen 1

may be sufficient for a tutorial.

For an engineering project, more descriptive identifiers are usually preferable.

Examples:

Primary Crusher

Secondary Screen

Ball Mill

Rougher Flotation

or project equipment tags such as:

CR-001

SC-001

BM-001

Figure 19. Several units with clear equipment labels.

Good naming makes it easier to:

• read the flowsheet;
• identify equipment in results;
• compare simulation cases;
• export engineering data;
• communicate the model to other engineers.

The graphical flowsheet should remain understandable even to someone who did not build it.

Selecting a model is an engineering decision

Adding equipment to the canvas is easy.

Choosing the correct model requires more thought.

Before selecting a model, consider what information you actually have.

For example, suppose you need to simulate a crusher.

You may have:

• only a known product PSD;
• CSS and general operating information;
• detailed plant survey data;
• equipment-specific information;
• calibrated breakage parameters.

These different data sets may justify different modeling approaches.

Figure 20. Data Available → Appropriate Model Complexity.

This principle applies throughout the DPSIM library.

Model selection should therefore follow the engineering question rather than the desire to use the most detailed model available.

Model parameters come next

Once an equipment model has been added, it normally requires parameters before its behavior is fully defined.

Depending on the selected model, these parameters might include quantities such as:

• equipment dimensions;
• operating settings;
• partition parameters;
• water split;
• recovery;
• residence time;
• specific energy;
• power;
• material-dependent parameters.

We will explore the equipment editing interface in detail later.

For now, leave the newly added equipment with its default parameters.

Our immediate objective is to construct the flowsheet topology first.

Building the first process sequence

Using the material feed created in the previous tutorial, add one process equipment item beside it.

For example:

Editable Feed

followed by:

Crusher

The canvas should now contain two separate objects:

Editable Feed Crusher

Figure 21. Feed and crusher positioned in sequence without a material stream.

Figure 21A. Feed and process equipment positioned on the DPSIM flowsheet.

At this point, they are only positioned next to each other.

There is still no material connection between them.

DPSIM does not infer process connectivity from the graphical position of equipment.

Placing a crusher beside a feed does not mean that the crusher receives that feed.

The units must be explicitly connected through a stream.

This distinction is fundamental:

Position defines the drawing.

Streams define the process connectivity.

What we have established

The project now contains:

Material definition

Components, size classes, flowrates, PSD and composition.

And:

Process equipment

A model-backed unit placed on the flowsheet.

The next step is to connect these elements so that material can move through the process model.

In the next tutorial, we will create material streams, connect equipment ports and begin building the actual flowsheet network.

We will also see how DPSIM distinguishes the origin and destination of each stream and why connection direction matters.

Figure 22. Preview showing Feed connected to Crusher by a stream.