Solids Process Modeling in Aspen Plus

8/9/2019 Solids Process Modeling in Aspen Plus

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2014 Aspen Technology, Inc. AspenTech, aspenONE, the Aspen leaf logo, the aspenONE logo, and OPTIMIZE are trademarks of Aspen Technology, Inc. All rights reserved.11-4823-0414

Jump Start: Solids Process Modeling in Aspen Plus

A Brief Tutorial (and supplement to training and online documentation)

Jennifer Dyment, Product Marketing, Aspen Technology, Inc.

Claus Reimers, Product Management, Aspen Technology, Inc.

Ajay Lakshmanan, Product Management, Aspen Technology, Inc.

Matthias Pogodda, Software Development, Aspen Technology, Inc.

Wilfried Mofor, Product Management, Aspen Technology, Inc.


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Jump Start: Solids Process Modeling in Aspen Plus V8

Table of Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

The Aspen Plus User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

First Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Solids Flow sheet Templates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Specifying Global Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Specifying Solid Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Specifying Property Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Specifying Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Specifying Stream Class. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Particle Size Distribution Meshes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Streams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Unit Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

The Model Palette. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Dryer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Spray Dryer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Crystallizer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Granulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Crusher. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Fluidized Bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Conveying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Results Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Plots. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Activated Economics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23


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IntroductionSolids process modeling with Aspen Plus provides an integrated solution for simulating processes containing solids. With

the tools provided, it is easy to characterize and model these components and obtain reliable results based on the worlds

most comprehensive property database and proven simulation technology. This functionality bridges the gap between

process engineering and particle science by providing the tools to seamlessly integrate rigorous models for solid streams

and unit operations with typical fluid process models. Now users can simulate processes that contain both fluids and

solids in the same simulation environment, allowing accelerated production of consistent, conceptual designs.

This document serves as a simple getting started guide for users who are inexperienced in Aspen Plus modeling. We

will take you through the most common progression of how a process designer creates a simulation and implements solid

components and unit operations. This is not meant to be used as a stand-alone reference document. We recommend that

a range of other resources be called upon to give the new user a comprehensive view of how to use solids modeling in

Aspen Plus. These may include:

AspenTech support website (support.aspentech.com) contains a wide range of knowledge base items and provides

answers to frequently asked questions AspenTech self-guided examples are also available on aspenONE Exchange or can be accessed by going here:

http://www.aspentech.com/October_2013_solids_modeling_demo_AT/

AspenTech courseware available in on-line and in-person versions provides formal training on process modeling

AspenTech business consultants

This document covers solids modeling in Aspen Plus. This guide assumes that the user has Aspen Plus V8.4 or higher

installed on their computer. Most features were introduced with V8.0, such as particle size distribution characterization

and a majority of the unit operations. See Table 1 below for more information.

The Aspen Plus User InterfaceWelcome to the Aspen Plus user interface. There are a few main components that you need to be familiar with in order to

follow this guide. Table 1 labels each of these.

Table 1: Solids Related features highlighted for the Aspen V8.0, V8.2, and V8.4 releases

Version Date of Release Features

Aspen Plus V8.0 December 2012

Integration of 25 SolidSim unit operations

PSD characterization

Solids-related results representation

Aspen Plus V8.2 May 2013

Economics for solids processing (Activated Economics)

Total of 38 SolidSim unit operations integrated

Enhanced PSD definition and results representation

Aspen Plus V8.4 November 2013

Conceptual models

Spray dryer unit model

Reactions in fluidized bed unit model
http://www.aspentech.com/October_2013_solids_modeling_demo_AT/http://www.aspentech.com/October_2013_solids_modeling_demo_AT/


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Figure 1: Main components of the Aspen Plus user interface

First StepsThis section talks about the first steps you must take to include solid components in your model. It does not cover every

step in creating a flow sheet. In order to be certain you do not skip important steps, click the green arrow (the Next

button) in the Run group on the Home tab, after each action to move on to the next mandatory step (Figure 2).

Figure 2: The Next button

Solids Flow Sheet Templates

When you create a new model, you have the option to select a template. On the Start Page, click New in the upper left

hand corner. In the pane that appears, you will notice that there are a variety of installed templates listed in the left

sidebar. Select the Solids category. You will have the choice to use a solids template with either English or Metric units

(Figure 3). This will automatically specify the global units, set the stream class to MIXCIPSD, and set the flow basis to

mass.


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Figure 3: Solids templates

Specifying Global Units

If you do not use a template, you must specify the global units manually. The global units dictate what unit set is

automatically applied to all quantitative variables in the model. There are two ways to specify global units. You can either

select the desired unit set from the dropdown in the Units group on the Home tab, or you can open the Setup

Specifications form the Navigation Pane and select it there (Figure 4). Global units can be changed mid-way through the

design process.

Figure 4: Specify global units


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Figure 6: Specify a stream as solid

Specifying Property Method

The next step in creating a flow sheet is to select the property method that will be used for all of the internal flow sheet

computations. On the Methods Specifications form, choose the desired property method from the Method name

dropdown list (Figure 7). You should decide which method to use based on the type of components that you are modeling.

For most cases with only solid components, the IDEAL method is likely sufficient.

Figure 7: Select property method


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Specifying Properties

Since the properties for solids are different than the conventional properties for fluids, it might be necessary to manually

manage those that apply to your process. In the Navigation Pane, select the Methods folder, then Parameters. Then

Click New and select the type of parameter in the pane that follows (Figure 8).

Figure 8: New property specification

Next fill in the matrix of parameters and components as desired. Hover over any of the parameters in the dropdown list to

see what the variables stand for (Figure 9).

Figure 9: Specify properties for desired compounds


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Specifying Stream Class

Once you complete all of the property specifications, you can move on to flow sheet specifications in the Simulation

Environment. In the Setup Specifications form you must select an appropriate stream class. To determine which is

best, hover over the different choices on the dropdown menu to see suggestions (Figure 10). Typically, MIXCIPSD is a

good choice when conventional solids are present with a particle size distribution.

Figure 10: Specify stream class

Particle Size Distribution MeshesSolids process modeling in Aspen Plus allows users to track the particle size distribution of different solids species for

each stream in your process. In order to do so, you must create a PSD mesh. In the Navigation Pane, go to the Setup

folder, then Solids, and select PSD. In order to define the PSD mesh, you either select a pre-defined mesh type (e.g.equidistant, geometric, or logarithmic) and enter the necessary parameters or you define your mesh manually (e.g. user

selection) as tabular data. For the later option, users can copy and paste data from spreadsheet tools (e.g. MS Excel). Fill

out the required inputs and select Create PSD Mesh (Figure 11). While the first mesh you define (named PSD by

default) is used for the simulation, additional meshes can be created for streams that have different particle size

distributions. To create additional meshes, go to Solids and select the PSD Mesh tab. Then choose New (Figure 12).

It is also possible to create new meshes on the stream data input (see streams)..

Tips and Tricks: You can always manually specify properties for components. This is especially

helpful when working with compounds that are not well documented (such as different grades

of coal).


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Figure 11: Create PSD mesh

Figure 12: Create additional PSD meshes

StreamsEvery stream that you produce has its own input form in Aspen Plus. If a stream has only solid components, it is important

to only fill out the CI Solid tab within this form and leave the Mixed tab blank. If a stream is only partly solid, you must fill

out both.

The CI Solid (which stands for conventional inert solid) tab has three sections: Specifications, Component Attribute, and

Particle Size Distribution. You must fill out both the Specifications and Particle Size Distribution sections at a minimum. By

default, only the Specifications section is initially visible, so click the arrow next to Particle Size Distribution to reveal it

(Figure 13).


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Figure 15: Use a distribution function to populate the PSD for a specific stream

Unit OperationsTable 2 shows a list of all of the solids unit operations available in Aspen Plus. This section only focuses on getting started

with five of the most common blocks. To find more detail on any of these or to learn about the unit operations not

discussed here, check out the Computer Based Training Courses available on the AspenTech support website.

Table 2: Solids unit operations in Aspen Plus

Unit Operation Block Name Tab

Classifier Classifier Solids

Crusher Crusher Solids

Crystallizer Crystallizer Solids

Convective Dryer and Spray Dryer Dryer Solids

Granulator/Agglomerator Granulator Solids

Multi-stage Solids Waster andCounter Current Decanter

CCD Solids

Screen Screen Solids

Single Stage Solids Washer Swash Solids

Centrifuge Cfuge Solids Separators

Cyclone Cyclone Solids Separators

Electrostatic Precipitator ESP Solids Separators

Fabric Filter FabFl Solids Separators

Filter Filter Solids Separators

Hydrocyclone HyCyc Solids Separators

Venturi Scrubber Vscrub Solids Separators

Fluidized Bed FluidBed Solids

Solids Conveying Pipe & Pipeline Pressure Changers


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The Model PaletteTo open the Model Palette, click the Model Palette button in the Show group on the View tab (Figure 16). There

are two tabs on the Model Palette that contain solid unit operations, the Solids tab and the Solids Separators tab

(Figure 17).

Figure 16: The Model Palette button

Figure 17: The solids model palettes Solids (top), Solids Separators (middle), and Pressure Changers (bottom)

Dryer

There are two ways to model a dryer in Aspen Plus: shortcut dryer and convective dryer. There is also an option

to model a Spray Dryer in Aspen Plus. Please see the section below. In order to switch types, use the dropdown menu on

the Specifications tab for the dryer (Figure 18). The shortcut dryer allows you to model the unit operation with a minimum

of information and can be used for any type of dryer. The convective model requires additional material streams for inputand output of a drying gas (Figure 19) and requires more information. This is the more rigorous model.

Figure 18: Select dryer type


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Figure 19: Material streams for convective dryer model - red indicates a required stream, while blue indicates an optional stream

There are a number of self-guided examples pertaining to modeling dryers in Aspen Plus available on aspenONE

Exchange. Examples include a belt dryer, fluidized bed dryer, mill dryer, flash dryer, and a batch dryer.

Spray Dryer

The Spray Dryer model is found in the Dryer block and allows you to model a wide range of industrial spray

dryers. The model is based on single droplet drying kinetics and does not consider the coalescence of droplets or the

agglomeration of particles. The model considers multiple aspects of the spray dryer including atomization, droplet

movement, drying, and particle formulation.

Under the atomization tab, users have the ability to specify the type of model used for the droplet size distribution,

including a built-in atomization model.

Figure 20: Atomization can be specified with the atomization tab of the Spray Dryer unit operation

The droplet movement is considered as downward fall and the equation of motion is derived from a force balance with

ignores lift. The model considers the first (constant drying rate) and the second (falling drying rate) period. The second

drying rate is described by use of a normalized drying curve. The normalized drying curve can be defined as tabular data or

by use of a drying curve function. Particle formulation starts after the moisture content of the particle reaches the critical

moisture content. Particle formulation can either be described with a solid particle model or with a porous particle model.


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Wet ParticleDroplet

Solid Particle

Porous Particle

Const

Diameter

IdealShrinkage

IdealS

hrink

age

1st Drying Stage 2nd Drying Stage

Xcrit

Figure 21: After critical moisture is met, the particle can either shrink in diameter to a solid particle or maintain a constant diameter and become a

porous particle

There is a self-guided example pertaining to modeling a spray dryer in Aspen Plus available on aspenONE Exchange.

Crystallizer

The crystallization block allows you to model steady-state crystallization. To do so, you can choose between

three different calculation methods: solubility, chemistry, and user subroutine (Figure 20).

Figure 22: The crystallizer form: input calculation method and operating mode

Each method requires a different set of input parameters, so you can choose how to calculate based on available propertyand operating information.

Granulator

The granulator block allows you to model the growth of particles by either granulation or agglomeration. In

addition to this, the block has a short cut model that allows you to define the outlet PSD (conceptual/short-cut model).

Table 3 summarizes the minimum stream requirements for each of these options. If you include a gas stream, the model

assumes a fluidized bed granulator or agglomerator and you cannot use either of the shortcut methods.


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Table 3: Granulator methods and their associated stream requirements

If you select particle growth by granulation, there are two available calculation models: mixed and plug flow. In mixed, all

parameters are independent of position, whereas in plug flow, size is dependent on position. Both models assume:

Steady state process

All particles are spherical

The suspension and particles are homogeneous

In the case of a fluidized bed granulator, solids may be elutriated or entrained by the fluidizing gas. To consider this, you

must add a fluidization gas stream to the block and specify the cross-sectional area of the granulator and the separation

sharpness (Figure 21).

Figure 23: Specify elutriation parameters for a fluidized bed granulator

There are self-guided examples for modeling granulation and agglomeration in Aspen Plus available on aspenONE

Exchange.


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Crusher

You can model a variety of crushers and mills with the crusher block. Aspen Plus provides three methods to

determine the outlet PSD:

Use an equipment model (e.g. hammer mill)

Determine outlet PSD from a power and distribution function

Define outlet PSD by use of a distribution function or tabular data

If you want to use an equipment model, you must choose the equipment type and provide the necessary geometry and

operating parameters. (Figure 22).

Figure 24: Specify crusher type

For a first estimate, it might be sufficient to specify the outlet size distribution or determine it based on the comminution

power. If you wish to use a comminution power, you must provide a Bond work index on the Grindability tab and specify if

you wish to use Bonds, Rittingers, or Kicks law to calculate it (Figure 23). Table 4 summarizes the appropriate situations

for each law.

Table 4: Determine the appropriate comminution law


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Figure 25: Specify comminution law and bond work index for a crusher

You can define the outlet PSD by using either distribution functions or by using tabular data.

Figure 26: Specify outlet PSD using tabular data for a crusher

There is a self-guided example for modeling crushing and screen potassium chloride in Aspen Plus available on aspenONE

Exchange.


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Additionally, you can filter what type of data is shown in the stream results by selecting a category from the Format

dropdown menu (next to the Display dropdown). To view the particle size distribution of each screen in tabular form,

select SOLIDS.

Plots

There are a variety of plots that you can create to visually analyze your data (PSD, Separation Efficiency, etc.). To generate

a plot, open the form for a unit operation or material stream and select the appropriate button from the Plot group on the

Home Tab. Note that you may have to scroll down to reach the desired button. You can also view all the available plot

types by clicking the down arrow below the scroll bar (Figure 30). To determine what type of information is displayed on

each plot, hover over the button.

Figure 35: Select the desired type of plot

Bear in mind, different types of unit operations and material streams are conducive to generating different kinds of plots.

For example, you cannot generate PSD plots unless solids are present.

Tips and Tricks: Data from the matrices provided by the model and stream summaries can

easily be highlighted and then copied and pasted directly into Microsoft Excel.

Note: You can only generate plots if you have run the simulation and obtained results.


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Activated Economics

While developing a design, you can utilize activated economics to explore different configurations and options to choose

the most cost effective design. With activate analysis, you can explore priliminary cost analysis with the click of a bottom

and explore the costs associated with each step by hovering over the unit after running activated economics.

Figure 36: Economic Analysis was done for the crushing section of this process to determine a first estimate of the cost of the project


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Additional ResourcesFor further information on solids process modeling with Aspen Plus please consult:

Public Website:http://www.aspentech.com/

Support Website:

The support website provides an extensive and growing knowledge base as well as Computer Based Training (CBT)

Courses

http://support.aspentech.com/webteamasp/My/FrameDef.asp?/webteamasp/My/product.asp?id1=4&id2=''&id3=all

Example Files:

Click the Examples button on the Get Started tab when you open Aspen Plus to see some out of the box simulations.

Using aspenONE Exchange or the support website, you can also access Self Guided Examples, which include both anexample simulation and a step-by-step guide to work through the example. These self-guided examples can also be

accessed here:http://www.aspentech.com/October_2013_solids_modeling_demo_AT/
http://www.aspentech.com/October_2013_solids_modeling_demo_AT/http://www.aspentech.com/October_2013_solids_modeling_demo_AT/http://www.aspentech.com/October_2013_solids_modeling_demo_AT/


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About AspenTech

AspenTech is a leading supplier of software that optimizes process manufacturingfor energy, chemicals,

engineering and construction, and other industries that manufacture and produce products from a

chemical process. With integrated aspenONE solutions, process manufacturers can implement best

practices for optimizing their engineering, manufacturing, and supply chain operations. As a result,AspenTech customers are better able to increase capacity, improve margins, reduce costs, and become

more energy efficient. To see how the worlds leading process manufacturers rely on AspenTech to

achieve their operational excellence goals, visit www.aspentech.com.
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Solids Process Modeling in Aspen Plus