In order to modify the properties of non-conventional components (such as biomass in your case) within a Fortran subroutine while using Aspen Plus, you need to make sure you are accessing the correct data structures for your non-conventional components.

From your description, it seems like you are running into an issue with accessing properties of non-conventional components (like biomass) within the stream structure. Here are a few things to keep in mind to help resolve this issue:

1. Check Stream Structure for Non-Conventional Components

The stream structure in Aspen Plus contains information about components, their flows, and physical properties. For non-conventional components like biomass, the data is stored in a specific section of the stream structure. You may need to access these components in a slightly different manner than conventional ones.

• Array Layout for Stream Components:In Aspen Plus, the stream structure typically stores component data in an array format, with each component represented in a single column in the array. For non-conventional components (such as solids), the data may be placed in separate arrays, which could be why you're not seeing it directly in the conventional stream array.Conventional components often occupy the first part of the array. Non-conventional components such as biomass or solid materials (e.g., CISOLID) may require accessing a different segment of the array or using a specific API or function call to retrieve or modify their properties.

2. Use Specific Commands for Non-Conventional Components

To access and modify the properties of non-conventional components, you may need to include additional commands or calls specific to handling these types of components.

• For example, you could try using ASPEN_INTERFACE functions to access component data more explicitly. These functions allow you to retrieve properties of both conventional and non-conventional components.
• Use ASPREP or similar functions for input-output operations if you're working with solid components in a non-conventional form.

3. Review the API for Solid and Non-Conventional Components

Aspen Plus provides specific APIs for handling different types of components:

• For solid components (like biomass), you may need to access the data via the "Solid Component" library (CISOLID) or other non-conventional structures.
• Ensure that your subroutine is specifically handling the biomass or solid components through the correct API function (e.g., SSSOLID for solids).

Check Aspen's help documentation for detailed instructions on accessing and manipulating solid (CISOLID) components.

4. Additional Command to Access Non-Conventional Component Data

You might need to use an additional GetCompData or similar function that handles non-conventional components. This function will allow you to fetch the component data explicitly for solid and non-conventional components.

Example of how to access component data:

CALL GetCompData(stream, 'CISOLID', componentIndex, flow, properties)

In this example:

• stream refers to the stream object you're working with.
• 'CISOLID' specifies the solid component type (biomass, in your case).
• componentIndex corresponds to the index of the biomass or solid component in the array.
• flow and properties are the variables used to store the fetched data.

5. Subroutine Modifications

To implement the improved kinetics for tar formation (as per the Abdelouahed (2012) kinetics), you will need to modify your subroutine so that it can handle biomass as a non-conventional component properly. Here’s a basic structure of what to look for in your subroutine:

• Identify biomass as a solid (non-conventional) component and treat it separately in the subroutine.
• Modify kinetics based on the biomass flow and properties accessed from the correct part of the stream.
• Implement logic to calculate the tar formation using the new kinetics and update the biomass flow accordingly.

Example structure:

! Fetch biomass data CALL GetCompData(stream, 'CISOLID', biomassIndex, biomassFlow, biomassProps) ! Update biomass properties based on Abdelouahed (2012) kinetics biomassFlow = biomassFlow * newKineticsFactor ! Update stream data with modified biomass flow and properties CALL SetCompData(stream, 'CISOLID', biomassIndex, biomassFlow, biomassProps)

Conclusion:

To solve your issue, ensure you are accessing the biomass properties correctly by referring to the specific section in the stream structure that handles non-conventional components. Additionally, modify your subroutine to work with solid and biomass components through the appropriate API functions in Aspen Plus.

I hope this helps! Let me know if you need further clarification or examples.

Hello Raghad Mouhamad,

unfortunately, your ChatGPT answer is not helping. Would you mind giving precise help instead of simply copying an AI answer?

Greetings,

Marc

I finally found the solution for my problem. The stream structure is as described in the Aspen Plus User Models Handbook. So, the structure is:

(MIXED flow rates;

MIXED attributes;

CISOLID flow rates;

CISOLID attributes;

NC flow rates;

NC attributes).

However, there is a deviation from how I expected the structure to be causing my problem:

Each substream lists every component (MIXED+CISOLID+NC) in the flow rate section. However, only for components belonging to the substream, the actual flow rates are listed (e.g. Flow rate of a NC-component in the MIXED-substream is zero, but there is a line reserved for the NC component).

I recommend to implement a command in the Fortran-subroutine to write the input and output stream (and maybe also interim results) in a .txt to get a better understanding for the simulation. A disadvantage of writing to a .txt is the subroutine takes longer to run.