Introduction
What is the Reactor?
Hydroprocessing reactors play a pivotal role in the oil and gas industry, serving as crucial units in refining processes that improve the quality of hydrocarbon products by removing contaminants.
These reactors operate under stringent high pressure and temperature conditions to catalyze the desired chemical reactions. The operation of these reactors requires precise control, especially during the heat-up and cool-down processes, to maintain safety and efficiency.
Figure 1: Reactor Asset
How do we simulate it for the engineering analysis with Akselos Integra?
During the heating and cooling processes in hydroprocessing reactors, a variety of technical challenges related to temperature and pressure can emerge, necessitating precise control to prevent operational disruptions and ensure safety.
These problems can include Differential Thermal Expansion. Thermal Shock, Pressure Imbalance, or Embrittlement Risks
- Monitor Reactor status in operational condition: Under the heat-up and cool-down procedure, simulate and capture the behaviors of Reactor by Digital Twin solution.
- Modifying operational procedure to optimize asset up time.
In this article
Below are the two available journeys that a new user can take to familiarize themselves with the MPT Assessment on a Reactor model.
- Journey 1: Explore via Sample Collection
This process utilizes a pre-made collection by Akselos to help speed up the process of learning the inner working of the model.
- Journey 2: Build Model from Scratch
This process allows users to start from scratch and is intended for users with more time to learn the ins and out of the simulation and model building process using Akselos Modeler.
Figure 2: Akselos simulation workflow
In this article, we will highlight the path taken when a Sample Collection is used. And for more information about how a complete model is built within Akselos Modeler, you can check out the available materials linked below.
This article serves as a walkthrough for the Reactor model, focusing on utilizing a sample collection to streamline the learning process (Journey 1).
Before we start
This article targets individuals with a foundational understanding of the Akselos Modeler and access to the Akselos Customer Dashboard. If you're unfamiliar with these, the following articles may be beneficial:
- Using Akselos account
- Download and install our simulation software
- How to use Akselos Modeler
We've assembled a sample collection of a Reactor model for your use. Import it via the following link:
How to import a collection on Akselos Modeler?
Please note: To access any sample collections within our Library on the Akselos Dashboard, please reach out to our support team at [email protected].
Below is an overview of how the Akselos Modeler UI is laid out. These terms will serve as future references for describing these areas as well.
Figure 3. Akselos Modeler UI overview
Reactor model in Akselos Modeler
The Reactor asset is equipped with thermal sensors, there is one at each nozzle and a pair at each elevation level of the vessel shell.
Overview
Reactor model summary
As mentioned above, the sensor data and environmental condition of the Reactor will be recorded and used as input data and initial conditions for the simulation. The data is converted into the following parameters:
- Material: This is based on the material used in the Reactor asset, Thermal-Elastic material is used and the parameters are modified to best represent it.
- Boundary Conditions: The Reactor is sit on solid ground and is bolted down, this will be represented as a fixed boundary condition on the bottom surface.
- Loads: The loads are modeled based on the input temperature and pressure sensor data and physical properties of the Reactor such as material density.
Further details on how to setup it up and why it is needed will be given in the following sections.
Reactor Model Configurations
Materials
Material selection is a crucial part in any engineering project, as it must endure the harsh environmental conditions, and withstand countless operational cycles. Therefore, this structure is constructed using specialized alloys to fit its unique operational requirements. This causes the material to exhibit unique qualities, which must be replicated in Akselos Modeler for the engineering assessment to be valid.
This is why Thermal-Elastic material is used when modeling this asset in Akselos Modeler, this allows the material properties to be customized so it closely mimics the behavior of the real allow.
Figure 4: Material Properties in Akselos Modeler
The Material parameters can also be represented with a graph on the Table and Charts Tab. This is very useful for temperature dependent materials such as the case here.
Figure 5: Closer look at Material Properties in the Property Tree
To check this, expand the Components tab and select a component. Then, choose Subdomain, and the Property Tree will populate with information about the material of the selected component.
Boundary Conditions
A boundary condition defines how the system can interact with its surroundings, specifying things like fixed positions, applied forces, or heat transfer rates. By setting these boundaries, engineers create a realistic environment within the simulation, allowing them to predict how the system will behave under different conditions.
In this case, the structure is laid on a solid foundation and bolted down. So there will be a Dirichlet Boundary condition on the bottom surface of the Reactor Model to reflect this.
Figure 6: Dirichlet Boundary Condition representation in Akselos Modeler
In Akselos Modeler, a Dirichlet Boundary condition is represented with a black sphere, along with the axis that it is restrained in. In this case, it is all three axes.
Figure 7: Turning on Boundary Condition visualization in Akselos Modeler
If it is not already being displayed, you can turn it on by clicking the eye icon on the Graphic Window. This will drop down a visualization settings menu. Check the Boundary Condition box to turn on the visualization.
Loads
During the operation cycle of a Reactor, there are factors such as Internal Pressure, the Weight of the structure, the Thermal Expansion when temperature changes and the Hydrostatic Load of the liquids contained inside the Reactor.
Those operational loads will be represented in Akselos Modeler with the load elements below:
- Internal Pressure: This load represents the pressurized vessel under an operation cycle. This value will be based on the sensor data input and will be mapped on to the interior walls of the Reactor. This will be updated every interval as new sensor data is uploaded.
- Self-Weight: This load represents the structure’s mass affecting it. This value will be based on the Material Density value set earlier and the specified g value. This will stay constant through out the assessment period.
- Thermal Expansion: This load represents the forces induced by the material expanding and shrinking during a heating cycle. This value will be based on the Material Properties defined above. This will be updated every interval as new sensor data is uploaded.
- Hydrostatic Pressure: This load represents the forces induced by the liquid contents inside the reactor. This will stay constant through out the assessment period.
To check the parameters associated with the loads, follow the steps below:
First, take a look at the Left Panel and drop down the Load Cases tab. This will present all the loads currently on the model. Clicking said load will update the Graphic Window with a visual representation of the load on the model. While the Property Tree will be updated with parameters associated with said load, such as magnitude, direction vectors, and target.
Figure 8: Load visualization in Akselos Modeler
Solution examinations
After a successful solving request, the result will be automatically downloaded from Akselos's servers. Akselos offers a selection of tools to help with examining the simulation result, we will introduce you to a few that can be utilized to extract more information from this simulation result.
Figure 9: Solution Tab UI Layout
Submit a solve command
Akselos Solver is put on the Cloud, and connected with Akselos Modeler through an account
Before submitting a solve request, you should have a final check on the model configuration and make sure your credentials to access the Akselos Cloud are still valid.
First to check your credentials ensuring an established connection to Akselos Cloud to submit a solve request, follow these steps:
Figure 10: Authentication tab
Figure 11: Checking credential status
Next, we can start the solve process.
Now, navigate to the Solution tab to initiate a Solve Request, but first recheck that the correct Solve List and Solve Scenario is selected. Click the Solve button on the left panel, this will send a Solve Request to Akselos Cloud with the current parameters setup and begin the solving process.
Figure 12: Solve page interface
If the request was successful, you will be able to see a new Solution Scenario pop up on the Solution List, located on the Left Panel. Here you can also check the overall progress of the simulation, in addition to the stage that the simulation is in. If more information is needed, on the right panel is a Job ID which is also a link which will direct you to the Akselos Dashboard Job Page, which will include every detail about the current simulation.
Figure 13: Solution Progress
Solution examination
After a successful solving request, the result will be automatically downloaded from Akselos's servers. Akselos offers a selection of tools to help with examining the simulation result, we will introduce you to a few that can be utilized to extract more information from this simulation result.
Figure 14: Downloaded Solution Page
Summary Tab
This tab shows the user the general information regarding the simulation results, such as the degree of freedom, run time, and simulation type. This can provide details at a glance for the users. If more information is required, there are more tools which will be introduced below to be utilized.
Figure 16: Simulation summary
Inspect Tab
On the inspect tab, more details about specific nodes can be viewed. Users can select a specific node, or can use the function to locate the Maximum and Minimum value, it will automatically jump to the appropriate timestep.
Figure 17: Node details
Figure 18: Node details
Here is an example when inspecting a node on the model. User can also select the node they wish to inspect, then the information will be updated on the Right Panel.
Usage of Clip planes
Clip planes can be used to more closely inspect the cross-section of the result. Multiple clip plane can be active at once to give an extra perspective.
Figure 19: Clip planes
As you can see from the figure above, the clip plane provides a whole new perspective to inspect problematic or hidden areas which otherwise could be overlooked.
Saving a Solution
You also have the option to download the solution to your computer, users will have the option to save this solution set for later reference or any other purposes. Follow the steps below to do this.
Figure 15: Saving a Solution
First, identify the solution set you wish to download from the Solution List. Right clicking on the desired solution will materialize a menu with multiple action available. Click Save As from this menu and specify the location on Windows Explorer.
Now, when you check the folder, you should see an extra file with a .asl extension. This is your saved solution.
Conclusion
This is the processes involved in solving a Reactor model for an engineering analysis on Akselos Modeler. The stress distribution and temperature will be used to evaluate the Utilization Factor of each components on the model, ensuring the asset is under a safe working condition. These assessment result can be uploaded and displayed on Akselos Dashboard. Continue with this article to learn more about that process. To see how a Dashboard work, check out the article below.
Read more
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