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Problem Statement: Most distributed control systems use the ISA Standard Form with the PID having specific tuning settings units where the controller gain has an associated dimensionless term. However, the HYSYS PID Controller algorithm does not allow the user to alter the structure of the PID. Furthermore, the HYSYS C... | Solution: addresses a main deficiency that occurs with using the HYSYS PID Controller Algorithm. The Process Variable (PV) is below the Setpoint (SP) set by the user. The user expects the final control element to take action once the PV is above the SP. However with PID sends signal to the final control element before ... |
Problem Statement: How to execute a macro at run-time during an Aspen HYSYS Dynamics run. | Solution: Some actions or complex routines can not be achievde just by using the event scheduler. In those occasions where further customization is required we can use a WinWrap macro. The macro execution cannot be directly selected as an action in the event scheduler, but we can change the value of a variable as an ac... |
Problem Statement: Example of a gas turbine dynamic simulation. | Solution: A gas turbine simulation has been configured using the following components:
- Two stage air compressor
- Gibbs reactor to represent the combustion chamber
- An expander to generate power
The hot flue gas temperature from the combustor is controlled by air to fuel ratio and a ratio controller has been used fo... |
Problem Statement: In our company there are two possible scenarios for transferring intermediate products between refineries:
1. Loaded transport shipped from Plant B to Plant A and loaded transport returning to Plant B
or
2. Loaded transport shipped from Plant B to Plant A and empty transport returning to Plant B
How ... | Solution: This type of modeling can be done with use of Mixed Integer Programming (MIP).
Please refer to the example below using MPIMS sample model.
* TABLE
TRANSFER
Table of Contents
*
Inter-Plant Transfers
TEXT
MIN
MAX
COST
!Product
!Source
!Destination
!Mode
*
FCXBAP
FCC ... |
Problem Statement: Using Aspen Simulation Workbook with Aspen Plus to model the UNIPOL polymer process for LLDPE/HDPE | Solution: It is possible to use Aspen Simulation Workbook and Aspen Polymers to model a UNIPOL process for the formation of polyethylene. The process is flexible, being applicable for both linear low density polyethylene (LLDPE) and high density polyethylene (HDPE). The example illustrates how to monitor the quality (... |
Problem Statement: How doI simulate hydrate inhibition? How to find inhibitor flowrate? | Solution: Hydrate inhibition simulation is quite simple. Add an inhibitor stream to your gas stream using a mixer. Then use a three phase separator to take out any liquid. Study the hydrate formation temperature at the outlet gas stream using a hydrate formation utility. You can use an adjust to vary inhibitor flowrate... |
Problem Statement: How can I create and use my own equation based control model? | Solution: We have quite a few Controller models which can be used for developing custom control models for the user. If you need to customize the controller models or you want to create your own controller , here is the work flow:
1) Please Select Custom modeling by going to Tools || Custom Modeling
2) Click on Add m... |
Problem Statement: There are some example scripts (declarations) in the Aspen Custom Modeler (ACM) Online Help of how to implement the ART (Aspen Reactions Toolkit) in a model, however there are not any ACM example files that illustrate this process. This | Solution: provides a simple example of a reactor model that uses ART.Solution
Aspen Custom Modeler provides the majority of the example scripts to use ART under: Help | Aspen Custom Modeler Contents | ART | Pre-packed Sub-models in ART. However, it does not provide some example files using this tool.
Attached is a simp... |
Problem Statement: This | Solution: provides examples on creating CSV files with different formats using an Aspen SQLplus query. CSV files are used to move information from Aspen InfoPlus.21 into other applications able to read this format.Solution
The following query creates space delimited output:
Basic CSV file conversion can be done with a ... |
Problem Statement: I have written a macro in Excel and I would like to retrieve data from my ACM simulation at the communication interval. However I have a task running changing the values with greater frequency and that causes the data to be retrieved whenever the task changes the value rather than at the communicatio... | Solution: It is not possible to override the frequency imposed by the task so the way to force the data to be retrieved only at a fixed interval defined by the user is to code that in the ACM simulation and in the macro. Attached is an example that shows how this is done. This example is a modified version of the FiveT... |
Problem Statement: Since both reactive distillation using RadFrac and RCSTR reactions assume equilibrium is reached, can an RCSTR be used to model one tray of a reactive RadFrac block? | Solution: Assuming that the reaction kinetics are identical, an RCSTR block will give results identical to one tray in a reactive RadFrac block.
The same rate expression should be used for the RCSTR and the RadFrac. The holdup in the column should match the reaction phase volume in the reactor.
The simplest way to veri... |
Problem Statement: If the tag naming convention within Aspen InfoPlus.21 needs to change (for example, to match the name of an OPC/DCS/PLC tag) and if you have calculations binded to these tag names within Aspen Calc, the calculation must be updated so that it can continues to give a valid result. This | Solution: provides an example to update the tag names in all the calculations using a SQLplus query.Solution
NOTE: Make sure to backup the ATC files associated with the calculations before executing the query.
Having a calculation like:
where values binding are defined as follow:
The following SQLplus query example wi... |
Problem Statement: Pure SQL allows to input values at runtime in the form of substitution variables. This | Solution: provides examples on how to use substitution variables on Aspen SQLplus.
Solution
Having an example query like:
Select ip_input_value, ip_input_time From ip_analogdef
where Name = 'ATCAI';
Substitution variables can be used as follow:
1) Substitution over WHERE Statement
Local TagName;
TagName = 'ATCAI'... |
Problem Statement: How to calculate the cool down temperature of a pipe segment after a shutdown downstream? | Solution: This case is set up to simulate a pipe cool down when closing the outlet valve.
Insulation details, ambient medium and ambient temperature (10 C) were specified in the Heat Transfer options for the detail model when the case was in steady state.
To test the model, please follow the steps below.
1. Close t... |
Problem Statement: How is an expander modeled in HYSYS Dynamics? | Solution: The attached document discusses the modeling of expander in HYSYS Dynamics, and the improvement of expander modeling in 2006.
In the attached HYSYS model the compressor is driven by the expander. For the expander, the Mafi Trench method is implemented in spreadsheet unit.
Keywords: Expander
References: None |
Problem Statement: Compressor Modeling in Aspen HYSYS Dynamics | Solution: Aspen HYSYS Dynamics can be used to view the response of compressors to conditions that vary from steady-state. Proper dynamic modeling of compressors can help prevent catastrophic equipment occurrences, such as compressor surge or flow reversal.
Please see the attached files.
Keywords: Compressor, surge
Ref... |
Problem Statement: How can you simulate an air cooled exchanger in Aspen HYSYS with fan speed to control the process side outlet temperature? | Solution: In Aspen HYSYS you can control the process side fluid temperature with fan speed control. However, the fan speed can not be connected directly with the PID controller output. The workflow would to link the demand speed in a cell inside a spreadsheet. This can be done by the drag and drop method.
The cell link... |
Problem Statement: An example for TEG dehydration in Aspen HYSYS dynamics | Solution: There are requests from Aspen HYSYS users for an example case of TEG dehydration simulation in dynamic mode. A generic TEG dehydration dynamic is provided with thisSolution. The users can download this file and make appropriate modification to represent a specific operation.
Note that converting a steady stat... |
Problem Statement: Is it possible to fit binary surface tension data? | Solution: None of the mixture surface tension models have binary parameters; however, the exponent of the mixing rule can be adjusted to better fit the data.
The mixture surface tension model is calculated using a general weighted average expression (R.C. Reid, J.M. Prausnitz, and B.E. Poling, The Properties of Gases a... |
Problem Statement: How to model electricity generation from coal using steam in Aspen Plus? | Solution: In order to model electricity generation from coal you will need to have data to specify the composition of inlet and outlet stream and properties of coal (for example laboratory analysis results).
Steps:
1. Create a new simulation
2. Define coal and ash as non-conventional components, carbon as solid... |
Problem Statement: How do you regress PC-SAFT parameters? | Solution: The SAFT (Statistical Associating Fluid Theory) EOS is a rigorous thermodynamic model based on perturbation theory. PC-SAFT (Perturbed-Chain Statistical Association Fluid Theory) EOS is an improved version of the very successful SAFT EOS, with some modifications on the expressions for dispersion forces. SeeSo... |
Problem Statement: Automation in Aspen Plus: how to add new entries within a two-dimensional node. | Solution: ThisSolution provides an example code in VBA that illustrates how to add new entries in a two-dimensional node. In this example we want to specify efficiencies for individual components in a RadFrac column. Basically, we are trying here to add new sub-nodes within a two dimensional node, so we will need to us... |
Problem Statement: Is it possible to model a dryer with nonconventional component defined by GENANAL? How do you define the moisture in the particle? | Solution: To model a dryer you need to define a moisture component on the Solids | Solid Characterization sheet. This is used by Conventional Solid Components. For Nonconventional components, the moisture is defined in the Proximate Analysis (PROXANAL). There is no way to define trapped moisture for a nonconventional c... |
Problem Statement: I have a vessel with level sensors located at fixed discrete heights within the tank. Is there a way to set up a digital input into a PID controller which takes into account of sensors located at discretized heights within the vessel? | Solution: It is possible to get HYSYS to report discretized integer values for the liquid percentage level inside the vessel. In the attached simulation, the liquid level of the vessel is exported into the spreadsheet labeled level sensor. Inside the spreadsheet this liquid level value is modified through a spreadsheet... |
Problem Statement: I have a contract engineering firm doing the engineering on my project, and I would like their costs to appear in a new, separate code of account (COA); how do I do this? | Solution: There are four basic steps you can do to have do this:
1. Create (Define) the new COA.
2. Allocate the new COA.
3. In Library Mode, create a new Unit Cost Library (UCL) item to add the actual costs.
4. Use the new UCL inside the project to get the costs in the project.
Keywords: Contract, Engineering, COA, Co... |
Problem Statement: I am using Aspen In-Plant Cost Estimator (AIPCE) and get the following error message: ?ERROR> 'CD - 1' ENTER EITHER COST OR PERCENT - PERCENT ENTRY IGNORED?. What does it mean and how do I fix it? | Solution: This is a project level error related to contract definition. In the contract definition form, either absolute value or percentage can be specified for contactor indirect, but not both. In the attached project, when opened with Aspen Capital Cost Estimator (ACCE), it can be seen that both cost in USD and perc... |
Problem Statement: Do you have some extensive example library of unit operation models to be used for dynamic simulation? | Solution: The attached file provides a complete package contributed by Alan Carlson, an experienced dynamic model developer.
Please note this is distributed as an example only, and we will not provide technical support. It can be used with version 2004.1 and higher.
The physical properties for the models are provided b... |
Problem Statement: Where are the user subroutines for RateSep located, and are they interchangeable with RateFrac user subroutines? | Solution: 1) Is this a typo? Should it say RateSep instead of RateFrac?
This is NOT a typo. These subroutines are for RateFrac only, not RateSep.
2) In general, are RateSep and RateFrac user subroutines interchangeable?
No. They are not interchangeable.
3) More specifically, would the above 4 subroutines work with ... |
Problem Statement: The RCSTR model is based on the perfect mixing assumption i.e., the reactor contents have the same properties and composition as the outlet stream. For example, if the contents of the vessel are partly vapor and partly liquid, the outlet stream will have both phases, too. Individual phases cannot be ... | Solution: This configuration could be applied in situations where a reaction is conducted in the liquid phase, but only a vapor product should be withdrawn. To separate the phases of the reactor contents, the stream leaving the RCSTR is introduced to a Flash2 block and the liquid outlet of the flash block (i.e., the li... |
Problem Statement: How to calculate the volume averages of distributions in cylindrical coordinate system? | Solution: The volume average of distributions in cylindrical coordinate is defined as:
In the example file attached, use is made of double integral (idxdy) option for distributions. In this model the temperature distribution is defined over the r and z domains.
The sum of the values of the temperature distribution is c... |
Problem Statement: I have a stream that is routed to two process units but with preference to be routed to the first unit, is there a way I can maximize the stream flowing to the first unit and send the excess to the second unit?
For example, as per below configuration, I want stream ABC which is produced from SABC to ... | Solution: In Table SYYY, add a Epenrow with a negative entry under the feed column ABC, the negative value simply mean it is a penalty cost $/unit of feed, in this way, PIMS will always try to feed ABC to SXXX up to the maximum capacity of SXXX, then only feed ABC to SYYY.
Note: You may refer to matrix file MPSBCD fo... |
Problem Statement: This case is set up to simulate an Emergency Shutdown System (ESD) when a certain pressure is reached and after waiting few minutes using the Event Scheduler.
The first event will close the vapour valve (PCV-001) after 30 seconds when the integrator is running. The controller (PIC-102) mode will be... | Solution: 1. Start Sequence A in the Event Scheduler.
2. Start the integrator.
3. Observe how the blue line (PCV-001 percentage open) goes down after 30 seconds of running the integrator. This is when the PCV-001 closes.
4. When the vessel pressure reaches 9.8bar, the event scheduler will wait 4 minutes before shutting... |
Problem Statement: Example of using query editor to see value of datasheet field | Solution: Please refer to attached query file.
Attached is a query that will show you a value of attribute ?Air Inlet Temperature? for AirCooledExchanger equipment type in Deg F unit.
To run a query and see the value of this attribute please follow the steps below.
1. Download the attached query file.
2. ... |
Problem Statement: How do I configure Citrix Server and Client? | Solution: Please refer to attached configuration document which shows step by step direction about Prerequisite, Installation & configuration of Citrix Licensing server, Installation & Configuration of Citrix server and Client.
Keywords: None
References: None |
Problem Statement: How can I create a submodel with yields based on component distributions? | Solution: In this example the submodel has one feed stream (consisting of four components) and three product streams. It is required that:
- 100% of component 1 and 75% of component 2 go into product 1
- 25% of component 2 and 80% of component 3 go into product 2
- 20% of component 3 and 100% of component 4 go into pro... |
Problem Statement: This | Solution: provides a step by step guide on how to create and use an Aspen Process Explorer trend plot on a form in Microsoft Excel VBA that can be loaded from a button on a spreadsheet. TheSolution also provide examples on how to programmatically add tags and scooter objects to the trend plot. Additional Tag and Scoote... |
Problem Statement: How do I model a multi-chamber fluidized bed dryer in Aspen Plus? | Solution: The attached Aspen Plus V8.2 demo will show you how Aspen Plus can be used to model a multi-chamber fluidized bed dryer and how entrainment of fine particles from the dryer can be described. There is an associated PDF to guide you through the steps.
This example will cover
· Basic description of the... |
Problem Statement: How do you calculate a required value to satisfy a design specification? | Solution: Attached is an example of calculating a required value to satisfy a design specification.
You can use a Balance block to calculate heat and material balances around an envelope of one or more unit operation blocks. The Balance block updates stream variables entering or leaving the envelope with the calculated... |
Problem Statement: How can I setup a depressuring utility for duty increasing or decreasing with time? | Solution: The users can use the Applied Duty mode in the Heat Flux parameters to configure duty for the depressuring study to be increasing or decreasing with time. The screenshot below shows that input heat duty can be set as
Q = C1 + C2 * Time
The coefficient C2, here only takes a positive value. If it is required... |
Problem Statement: Is it possible to use the NRTL-SAC model with electrolytes?
1.) Can a PH calculation be done using the NRTL-SAC model?
2.) Is there a simple example anywhere of the NRTL-SAC model being used for electrolytes so that we can see exactly what it looks like and how it is done? | Solution: Aspen Properties Excel Add-in does support electrolytes but it must use the apparent approach.
NRTL-SAC can be used for electrolytes in Aspen Plus, Aspen Properties, and Aspen Properties Excel Add-in. However, Aspen Solubility Modeler does not support electrolytes.
Two files are attached as examples:
1. ... |
Problem Statement: How to model siphon effect in Aspen Plus Dynamics | Solution: Refer to the attached steady state and dynamic model. In this dynamic model, you would see all the outlet valves were closed. Downstream tank were set to be empty.
If you run the simulation, you would see liquid is flowing from one tank to another. Look at the results while running the model.
Keywords: dyna... |
Problem Statement: Different alternatives to analyze utilities usage and minimize costs in Aspen Plus. | Solution: The attached examples illustrate three different alternatives in Aspen Plus that we can use to analyze utilities usage and minimize operating costs: Fortran sensitivity analysis, sequential modular (SM) optimization and equation oriented (EO) optimization. The last one is more robust for complex optimization ... |
Problem Statement: How do I configure signal bias in the PID controller In Aspen HYSYS? | Solution: The PV Conditioning page in the PID controller allows to handle the bias of the controller input signal (PV).
When the Bias radio button is selected the PV Sampling failure group appears. The signal bias can be specified in the “Bias The Signal By� field. This value can be in the PV unit or Percent PV ran... |
Problem Statement: I would like to set up the structure that equalizes the average quality between two groups of gasoline sales streams. How can I model such structure in PIMS? | Solution: Please refer to below example:
The goal is to equalize the average RON of ABC+BCD and CDE+DEF streams.
In T.ROWS E-rows are used to drive activities from sales vectors:
* TABLE
ROWS
SELLABC
SELLCDE
SELLBCD
SELLDEF
EDRVABC
-1.00000
EDRVCDE
-1.00000
EDRVBCD
-1.00000
EDRVDEF
-1.0... |
Problem Statement: If Aspen Plus does not accurately predict viscosity for a caustic (or other electrolyte) | Solution: , is there a way to improve those calculations?
Solution
Yes - obtain viscosity / temperature / composition data for the electrolyte mixture. If the case of NaOH, you would only need to regress the IONMUB-1 paramter (found under DATA | PROPERTIES | PURE COMPONENTS click on miscellaneous and then IONMUB-1). Si... |
Problem Statement: I would like to model this scenario: I have a FCC unit, there are 3 feedstocks like vacuum gas oil (VG1 and VG2) and Atmospheric Residue(AR1). Because of coke burning capacity limit, AR1 feedrate is dependent on total feedrate. Maximum total feedrate is 53MB. The relationship between AR1 feedrate and... | Solution: I create a simple LP model (this is not a full refinery model) as attached, to model this scenario, T. MIP (Mixed Integer Programming) is needed. Note that T. SABC is representing the FCC unit.
1. AAA, BBB, CCC are feeds entering SABC (Here, AAA and BBB representing VG1 and VG2 respectively, CCC represe... |
Problem Statement: How do you model the melting of a metal such as Copper? How do the results compare to data? | Solution: It is possible to use an RGibbs or an RStoic block to model the melting process. Two components are used: one for the liquid phase and one for the solid. For metals and other organic components, it is generally best to specify that the Inorganic data with parameters from Barin is searched first (on the Compon... |
Problem Statement: Can I write equations that contain variables from different blocks or streams on my flowsheet and display them on a plot? | Solution: Yes, this is possible. In Aspen Dynamics, you can use Flowsheet Constraint to write any equations that contain variables from different blocks/streams on your flowsheet. All variables defined in the Flowsheet Constraint will be displayed on the Local Variables table, you can then drag and drop these variable ... |
Problem Statement: How can I setup a template that will report a summary of the purchases and sales for each local model after an MPIMS run? | Solution: Attached is an example template. This template reports each local model on an individual worksheet. Purchases are listed followed by sales which are sorted by market.
To setup the template:
1) Run an MPIMS model
2) Place the template and the MPIMS results.mdb database in the same directory location or upd... |
Problem Statement: How do I estimate model parameters in Aspen Plus using measured particle size distributions? | Solution: The attached Aspen Plus V8.2 demo shows how to use the Aspen Plus data fit functionality to determine model parameters based on measured data. There is an associated PDF to guide you through the steps.
This example will cover
· Setting up a flowsheet that separates fine particles from coarse particl... |
Problem Statement: How do I model the pneumatic conveying of solids in Aspen Plus? | Solution: The attached Aspen Plus V8.2 demo shows how dilute and dense phase conveying systems can be modeled in Aspen Plus V8 using single pipes or pipeline networks. There is an associated PDF to guide you through the steps.
This example will cover
· Simulation of a dilute phase conveying in pressure mode
·... |
Problem Statement: How do you model bursting relief scenario in Aspen Plus Dynamics? | Solution: The Bursting Disk model in Aspen Plus dynamics is used for simulating pressure relief systems. It uses the same basic approach as that of an orifice plate.
The following points summarize the Bursting Disk model and its equations:
The model supports reverse flow
Adiabatic heat transfer is assumed.
Subcritical ... |
Problem Statement: How can a pipe network with multiple lines to a manifold be modeled in Aspen Plus? The outlet pressure of the manifold is specified. | Solution: In the attached Aspen Plus model, we demonstrate how to model a pipe network with multiple pipes merging at a manifold. In the example, 4 lines go into a mixer. The 4 lines should have the same pressure coming into the junction.
An important note is that this scheme works even when a significant number of lin... |
Problem Statement: Do you have an example of a feed forward control in Aspen Dynamics? Can you explain how to configure one using the blocks in the Aspen Dynamics control library? | Solution: The Aspen Dynamics control library includes a FeedForward model for a feed forward controller.
Typically you make the PV something like a feed flow to a column and the OP go to the manipulated variable e.g. a Reboiler duty or reflux flowrate. The Bias input connection can be connected to the output from a fee... |
Problem Statement: How to create a User Variable to use it inside an Adjust block? | Solution: In the attached example file there is one stream that goes into two different compressors in series.
The objective is to change the stream flow rate in order to achieve a specific value for the sum of both compressor's duty (total power).
The User Variables are defined in the first compressor (K-100), and the... |
Problem Statement: How do I configure delayed blowdown for a relief valve using the depressurization utility in Aspen HYSYS? | Solution: Knowledge baseSolution 138148 documents how a delayed blowdown can be simulated for Supersonic, Subsonic, Masoneilan and General Equations. ThisSolution addresses how the delayed blowdown can be simulated when user selects the Relief Vapor Flow Equation.
The user can modify the calculations in the spreadshe... |
Problem Statement: Why does the Liquid level in my vessel increase after depressuring? | Solution: It is expected that the liquid level should decrease after the dynamic depressurizing time is completed, however due to liquid swell the opposite might be the case.
An increase in the liquid level might mean that the final liquid density is lower than the initial liquid density, thus the final liquid inventor... |
Problem Statement: How can I simulate a cooling tower in Aspen Plus? | Solution: In order to simulate a cooling tower in Aspen Plus, you can use a RadFrac column model which is very versatile in terms of being deployed for multiple purposes.
In the attached example model file, you can find the following settings:
1. Under the properties environment the following conventional components ... |
Problem Statement: How to model a car coolant system in Aspen HYSYS? | Solution: An engine coolant is a heat transfer fluid that is designed to remove excess heat from the internal combustion engine. The majority of the heat goes out via the exhaust, however there is a need of a coolant to absorb part of engine heat and transport it to the radiator and dissipate it into the environment.
A... |
Problem Statement: When we want to access to a Stream-Vector, we can use many tools such as Sensitivity Analysis. When accessing to a Stream-Vector, we normally obtain all the arrays that are included (NCC+ 9). However, we may need only one of them in order to make some calculations to be studied in a Sensitivity Analy... | Solution: , we are going to focus on how to obtain the mole flow of each component in our simulation by varying another variable, for example, the temperature. We can obtain the mole flow for each component in every stream at different temperatures.
Solution
The simulation file attached to thisSolution is based on one ... |
Problem Statement: How is it possible to use Darcy's correlation for the calculation of pressure drop in a tubular reactor that is modeled with RPlug?
The following correlation gives the pressure drop over a differential length:
dP/dz = -2 * ff * rho * vel**2 / Diam
for turbulent flow (Re > 3000):
ff... | Solution: RPlug supports a user subroutine for the calculation of pressure or pressure drop. The attached files give an example and the source code of the subroutine that can be used. The fortran code contains many comments to explain how this works. The friction factor is calculated using Churchill's correlation.
Beca... |
Problem Statement: Do you have any depressurization example in Aspen Plus Dynamics? | Solution: Please find an attach example case that demonstrate vessel depressurization in Aspen Plus dynamics.Vessel initial pressure was around 49 psi and undergoes depressurization. Model simulate how long it takes to depressurize the vessel. A Task is created to close the feed valve and set boundary pressure to atm... |
Problem Statement: How do you write a user activity coefficient model? | Solution: This example demonstrates the development of a user activity-coefficient model and its implementation in Aspen properties/Aspen Plus.
The following activity-coefficient model is used:
ln(gamma) = Pi ( 1 - xi )**2
where,
i
-
refers to component i
gamma
-
activity coefficient
x
-
mole fraction
P
-
model paramet... |
Problem Statement: How accurate are the properties of Aqueous Nitric Acid? How can the Excel add-in for Aspen Properties be used to evaluate properties? | Solution: This package presents and evaluates the Aspen Properties physical-property model for the aqueous nitric-acid system. This application demonstrates the accurate and reliable physical properties that Aspen Properties provides for this important system and shows how they can be evaluated and studied through the ... |
Problem Statement: How do I model a fluidized bed agglomerator in Aspen Plus? | Solution: The attached Aspen Plus V8.2 demo will show you how a fludized bed agglomerator can be simulated in Aspen Plus V8. This demo uses the flux number approach to determine the pre-kernel so that the particle growth within the agglomerator depends on the operating conditions. There is an associated PDF to guide yo... |
Problem Statement: Can I have an example of conversion reactor with steps in Aspen HYSYS? | Solution: The partial oxidation method relies on the reaction of the fuel with Air in order to produce carbon monoxide and hydrogen as per the following reaction:
In this example fuel is considered as “methane” and Air is considered as “oxygen”.
Guidelines to build Simulation:
Properties Environment:
· ... |
Problem Statement: Can Aspen Plus show retrograde condensation? | Solution: Retrograde condensation can occur for some systems, particularly petroleum gases containing heavy hydrocarbons, found as single-phase fluids in deep reservoirs at high pressure and temperature (gas condensate fluids). If the pressure is reduced at constant temperature, it is possible to hit the dew-point curv... |
Problem Statement: Natural gas water content results comparison between Aspen HYSYS Peng-Robinson EOS with Bukacek correlations. | Solution: The attached HYSYS file demonstrates the use the Aspen HYSYS spreadsheet operation in conjunction with case study tool for validating the Natural gas water content results with Bukacek correlations.
Keywords: Bukacek, Water content
References: s: GPA 2002, please see the attached. |
Problem Statement: When to consider side exchanger in column targeting? | Solution: In this series of knowledgebaseSolutions, we demonstrate column targeting using the tools available in AspenPlus. The background on column targeting can be found in the work of V. R. Dhole and B. Linnhoff [2]. We use the LNG fractionation unit considered in the research of H. E. Alfadala, B. M. Ahmad, A. F. W... |
Problem Statement: Nylon6 production - Polymerization of caprolactam to Nylon 6 with step growth kinetics | Solution: This model is based upon the same Aspen Polymers Plus steady state model and the detail descriptions please see Aspen Polymers Plus manual. Briefly, caprolactum is polymerized in the presence of water to form Nylon6. This multi-stage model uses Polymers Plus to capture the polymer characterization, the polyme... |
Problem Statement: CDI can be used to generate the state space decomposition of a dynamic simulation. Is there an example of how one can write a state space model in Aspen Custom Modeler? | Solution: Attached is an example. There are two versions: one is working with the dense matrices and the other is working with sparse matrices.
The example is using Aspen Dynamics, with a RADFRAC block. The simulation has been linearized at steady state to generate the matrices in the files cdi_A.dat, cdi_B.dat, cdi_C.... |
Problem Statement: In the Fire Semi-Dynamic Flash calculation method in safety analysis why is the flash table showing two vapor mass flow peaks? | Solution: The Fire Semi-Dynamic Flash table can exhibit bi-modal peaks for the vapor mass flow rate. To demonstrate this point, in the attached simulation a Fire Semi Dynamics case is setup for a crude liquid stream. This crude liquid stream is a mixture of water and oil. The following screen shot shows the two peaks f... |
Problem Statement: In the Wetted (API) calculation method within safety analysis how is the temperature at the inlet of the relieving device calculated? | Solution: The relieving temperature highlighted under the scenario reference stream section is a calculated variable. A screen shot showing this calculated inside the safety analysis section is shown below:
The relieving temperature is determined as the bubble point temperature of the liquid portion of the referen... |
Problem Statement: How to use Data Fit tool in Aspen HYSYS. | Solution: The new Data Fit tool allows least square fit of model to one or more sets of plant data. Calibrate models in a few easy steps using the battle tested Aspen Data Fit algorithm to fit model to plant. The help page contains details on how to use this tool. The user can use F1 on Data Fit in the Navigation Pane ... |
Problem Statement: Example of Excel VBA to access performance curve for a Cooler in Aspen HYSYS | Solution: The performance curves for a cooler cannot be accessed with any standard automation method because this has not been fully wrapped for automation access. It is possible to obtain most of the tabular curves using the backdoor monikers. The monikers can be found by copying the value from Aspen HYSYS to Excel as... |
Problem Statement: Acid Gas Cleaning using a Physical Solvent (DEPG) | Solution: Example file published in Aspen HYSYS V8.6 that contains a typical flow sheet for the modeling of gas treating using DEPG. Acid Gas Cleaning is a feature of Aspen HYSYS that was first added in V8.3 and DEPG support has been added in V8.6.
Keywords: HYSYS, Acid Gas Cleaning, Sour Gas, H2S, CO2, DEPG, Selexol, ... |
Problem Statement: How do I model and optimize a belt dryer in Aspen Plus? | Solution: The attached Aspen Plus V8.2 demo will show you how an industrial belt dryer with multiple drying and cooling stages can be modeled in Aspen Plus and how such dryer can be optimized to reduce its energy demand. There is an associated PDF to guide you through the steps.
This example will cover
· Basi... |
Problem Statement: How do you regress aqueous heat of | Solution: data for an electrolyte system?Solution
For electrolyte systems, there are three major types of data that are commonly used for determining parameters of activity coefficient models:
1. Mean activity coefficient data in aqueousSolutions
2. VLE data
3. Heat of aqueousSolution data
Aspen Plus... |
Problem Statement: In a 'normal' specification of a stream, two state variables (e.g. pressure and temperature) and the component flowrates (or composition and total flow) are required user inputs. However, it is sometimes necessary to specify a stream with 'unconventional' or non-typical user inputs. In the below exam... | Solution: CALCULATION PHILOSOPHY / METHODOLOGY
As the stream composition is unknown, we cannot fully specify the stream by conventional means. Adjust operation(s) must be used to manipulate the composition (indirectly) to obtain the desired properties. As these Adjust operations will affect each other, the Adjust Manag... |
Problem Statement: It is possible to use Aspen Simulation Workbook (ASW) in Excel as a front-end for a Batch Dryer in Aspen Plus? | Solution: Attached is an ASW enabled Excel file that gives an example of an interface for a Batch Dryer Model. In this case, a sensitivity study in Aspen Plus was used to simulate the dynamic behavior of the Batch Dryer over time.
1. The attached zip file contains the model used and instructions on how to use the ... |
Problem Statement: Therminols are often used heat transfer fluids. Depending upon the version of Aspen Plus you are using, there may be limited or no data available in the databanks. Typically, data sheets for the various therminols may be obtained, but the user then needs to get this data into their Aspen Plus simulat... | Solution: The attached example can be opened in version 2006.5 and higher. It is an example of entering Therminol59 (a heat transfer fluid by Solutia) data. The data is attached as a PDF. The data is first entered as data regression file, and then after the regression is successfully completed, the Run Type is changed ... |
Problem Statement: How to model dry ice (CO2) cooling? | Solution: It is possible to model dry ice cooling using a heat exchanger (HeatX) where the solid/vapor phase transition is modeled using electrolyte chemistry. The CO2 needs to be defined as two components, one for the vapor and one for the solid. A salt type reaction is used to model the sublimation. The equilibrium b... |
Problem Statement: How do I model an Air Separation process? | Solution: To separate air into its components it has to be liquefied, and a gas can only be transformed into liquid state at temperature and pressure conditions below of those of its critical point.
The critical point of air is around Tc = -140.7 C and Pc = 37.7 bar. You have to keep in mind that for gas mixtures such ... |
Problem Statement: What is stream segmenting? Provide an example of how to do it. | Solution: Stream segmenting is splitting up a stream from its initial temperature to its final temperature into intermediate temperature sections. It is useful for streams that undergo phase change or have non-linear variations in enthalpy as temperature changes. A practical example is the crude pre-heat train in which... |
Problem Statement: How do you regress enthalpy, heat capacity and VLE data for an electrolyte system? | Solution: The ElecNRTL property package has the capability to correlate data from VLE (TPXY), enthalpy (HLMX), and heat capacity (CPLMX) together for electrolyte systems. The example file libr_h2o_drs.bkp is attached.
This example demonstrates that ElecNRTL can be used to correlate data from VLE (TPXY), enthalpy (HLM... |
Problem Statement: How do I model a circulating fluidized bed in Aspen Plus? | Solution: The attached Aspen Plus V8.2 demo shows a model of a circulating fluidized bed and demonstrates how the process can be optimized with regard to energy demand. There is an associated PDF to guide you through the steps.
This example will cover
· Basic description of the fluidized bed model
· S... |
Problem Statement: Sensitivity Analysis is a tool that one can find in both SM (sequential modular) and EO (equation oriented) | Solution: modes, but the type of results they give are completely different.
SM executes all the blocks for every possible value of the varied variables, and tabulates the results of the desired ones. On the other hand, EO evaluates the Jacobian matrix: the partial derivatives of each dependent variable with respect to... |
Problem Statement: Example to access the performance table results of a LNG exchanger through Automation. | Solution: The variables used in the performance table of an LNG exchanger have not been exposed as automation interfaces in Aspen HYSYS, and users cannot access to them directly using standard Automation procedures. However, the backdoor method can be used with the monikers of those variables for this purpose.
Property... |
Problem Statement: An Example of Styrene Production from Ethylbenzene. | Solution: Attached is an example of this process. This example will run in Aspen Plus v7.1.2 and higher
Process Description:
Figure 1 shows the process flowsheet of a typical styrene production process consisting of two adiabatic packed bed reactors with interheating, where dehydrogenation of ethylbenzene (EB) take... |
Problem Statement: When modeling solid polymer processes, typically there is potential for savings in the drying section. Savings can be generated by reducing the energy demand in drying, which can reduce the overall net operating costs. | Solution: The attached Aspen Plus V8.8 example will show how to model a solid polymer process in Aspen Plus and display how to optimize the process to reduce the net operating cost.
The example will cover:
· Setting up a solid polymer model
· Basic description and simulation of batch reactors, centri... |
Problem Statement: How can I run my VB / VBA program asynchronously with respect to the solver, and continue to use the application until Aspen HYSYS finishes calculations? | Solution: When accessing Aspen HYSYS through Automation it is important to note that by default Aspen HYSYS does not allow communication while it is solving. If information is sent to Aspen HYSYS from a client application, Aspen HYSYS does not return control to the calling program until calculations are complete. This ... |
Problem Statement: Is it possible to model the extraction of essential oils from wood pulp? | Solution: Wood pulp can be modeled as a nonconventional component; however, nonconventional components carry moisture as a single element of the component attributes. The moisture must be aqueous water. This means that we can’t really use that approach to simulate extraction of non-aqueous moisture components.
Instead ... |
Problem Statement: Where can I find an example file of Liquid - Liquid Extraction in Aspen Plus? | Solution: In the attached Aspen Plus V7.3 backup file a simple liquid-liquid extraction process is modelled. A liquid stream FEED containing 60 mol% water and 40 mol% acetone entering at 25 C, 1 atm will be extracted with a pure MIBK stream SOLVENT at the same exact conditions as the feed.
Point to Remember:
The 2nd Li... |
Problem Statement: How to rigorously model a kettle reboiler in Aspen Plus V8.8? | Solution: In Aspen Plus V8.8, the HeatX block was redesigned to include shortcuts to interactively design some designs on Shell & Tube Exchangers, such as kettle reboileers. In the file attached, there is an example file on a reboiler for a water-methanol service using steam as the heating fluid.
The steps to design a ... |
Problem Statement: The solubility user subroutine for the crystallizer does not seem to provide the input argument values as documented. | Solution: See the attached file for an updated version of the documentation. This will be included in the documentation for a future version of Aspen Plus. The attached subroutine also prints to the history file the value of the input arguments and demonstrates how you can get the concentration of the components.
Keywo... |
Problem Statement: How to convert a stream from the true component approach to the apparent component approach? | Solution: You can use the property sets to convert the stream composition from one approach to another, however if a block is set up to use the apparent component approach, no ions or salt may be present in the feed. Otherwise an error message will be issued:
Block: B2 Model: HEATER
*** SEVERE ERROR
... |
Problem Statement: How do I model a single effect absorption chiller in Aspen Plus? | Solution: Attached is an example of a single effect absorption chiller that user a Lithium bromide (LiBr)-WaterSolution as the working fluid.
Absorption chillers use a refrigerant-adsorbent pair as a working fluid. The two most common combinations of working fluid are Water/Lithium Bromide (LiBr) and ammonia/water.
P... |
Problem Statement: About the output arguments for a rate-based mass transfer coefficient subroutine: explanation, units and a practical example. | Solution: In Aspen Rate-Based Distillation, users can implement their own correlations to calculate the binary mass transfer coefficients (MTC) for the rate-based method. In order to reduce the size of the Jacobian matrix, the mass transfer coefficients in the user subroutine are expressed in the form:
where  is a fun... |
Problem Statement: How to create an ACM model ready to work with solids in Aspen Plus. | Solution: The interface between an equation oriented model (such as ACM) and Aspen Plus stream classes should be a port compatible with MOLE-FRAC specification, which basically means that for a MIXED substream connected to your model the following variables should be transferred: in mole basis F (total flow rate), T, P... |
Problem Statement: Why is my calculator block not taking into account imported/exported variables and not showing any results after I run simulation, even if it is specified correctly? | Solution: When you specify a calculator block, it is important to remember to include in the calculation the variables which are in Active streams and blocks. If you deactivate the blocks or streams (and variables within the block) which are included in calculator block Input specification, then Aspen Plus will not tak... |
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