Sharing Process Models

This is the check list of want you have to prepare to share a model of a technology model in the IETS data base.

An industrial process is defined by a list of the activities needed to deliver products or services in a given geographically located place.

Each activity (figure Figure 1) is realised by what we name a processing unit that generates one or more services or products by using equipment (processing assets), material, energy and human resources and generating as weel waste and emissions to the environment. A process unit is therefore defined by mass and energy systems exchanges with the technosphere and the environment.

A process unit model aims at representing the process unit exchange interfaces that a given process unit that realises a given process operation activity in a production process.

Refering to the process and energy system integration dimension, the role of energy in the processing units will be characterized by the work, the eletricity and the heat transfer needs as heating and cooling requirement with their corresponding temperature levels.

Figure 1: Processing unit activity in a given industrial process

How to prepare your process and technology models for sharing

Issue

When integrating a process unit into a larger system, the challenge is to ensure seamless interactions between the unit and the rest of the system. This requires a standardized approach to define the process unit’s inputs, outputs, operational boundaries and system interfaces.

Challenge

Complexity: Process units often involve multiple mass and energy streams, each with specific conditions typicaly calculated with advanced models.
Compatibility: The model must align with system-level exchanges and constraints (e.g., energy and material flow rates, adapt to process location, use of system level key performance indicators).
Scalability: The model should be adaptable to different system configurations and optimization objectives: models will be used to define markets of technologies, to define possible decarbonisation roadmaps for for a given product or to calculat ethe inmpact at the national or international levels.

Model development strategy

We assume that the process model is characterized by its entering and leaving flows and by the description of the list of intereconnected equipments used to realise the mass and energy conversion.

Define the process function

The process is first defined by a list of meta data that defines the function of the production process. The process is defined by a specific purpose of activity provided as product in the technosphere. Define the reference product and the production capacity, the production profile and the sustainability market values in economical, environmental and social terms.

Process function definition

Name:
CAS reference:
Industrial sector: to be selected in a list of industrial sectors
Process production capacity [ton/hour]:
Process profile [hours/year]:
System integration:
- Industrial Heat Flow [MJ/kg]: typical heat needs per unit of product to be used in the calculation for the integration in the energy system. This is a typical statistical value used in energy system models
- Industrial Heat temperature [°C]: typicalthe production temperature of heat needs of the process. This value is used to identify under whoch process catagory the process is operating
- Electricity [MJe/kg]: Typical electricity consumption (+) or production (-) per unit of product as reported in statistical market analysis
- Market production [ton/year]: for a given market what is the amount produced in the market of today. The market production can be regionalised: [Market, Production] where Market refers to a specific region. Those values will be used in energy system models like ENERGYSCOPE.

Define the Process connections to the technosphere

Refering to figure Figure 1, the process interface consist in the definition of the exchanges a process unit operation will offer to the background system. The process interface follows a modular approach that aims at representing the necessary steps to realise a complete process based on a block flow diagram.

Connectivity of the process to the background system means representing the material and energy flows exchanged with markets as well as the emissions released to the environment.

Mass Streams:
- Inputs: \(\dot{m}^{+}_{m}\) Raw materials, auxiliary chemicals, and utilities (e.g., water, air).
- Outputs: \(\dot{m}^{-}_{p}\) Products, by-products, and waste streams.
- Flow Rates: Quantify mass flow for each stream (kg/s or kmol/s).
- Composition and thermodynamic state: to thermodynamically characterize the flow
Energy Streams:
- Work/Electricity \(\dot{E}^{+}_{energy}\): Specify power requirements (kW) for compressors, pumps, turbines or reactors.

Typically a process unit does not have a heat transfer interface.

The process interface needs to be as close as possible to the process especially for the energy requirements. when you define a process interface model, will will in particular define the energy needs in term of heat exchange requirement and not with the utilities that are used today. It means for example that you will define a stream to be heated and not the natural gas consumption in the boiler.

Defining the process connectors

The folllowing structure is used to define a mass or energy connector to the technosphere and the environment.

Name [string]: name of the connector
Description [string]: a decription of the connector with assumptions that allow a clear undestanding of the connector.
Reference Mass flow rate [kg/s]: The mass flow rate is the reference mass flow rate of the connector for the process. It is the mass that flows through the connector per unit of time.
Type: type of the connector, possible values are:
- Product: for raw materials, product and by products, i.e. the materials flows that have a value in a market and that are related to a supply chain in the technosphere
- Energy: for electrical power or fuel flows
- Waste: for raw materials that are considered as waste, i.e. any matrial flow that will need a treatment to be released in the environment
- Emissions: for the material flows released in the environment
Market specification: specify the quality of the flow for a market
- Supply Chain: defines the type of supply chain like road, pipes,…
- Storage: defines the storage conditions and volume
Thermodynamic specification:
- Location: define the location of the flow data in the process model data base. This will be used to automatically collect the thermodynamic characterisation of the flow. This is used if a cape-open sockets exists for the model calculation engine.
- Enthalpy (\(h\)) [kJ]: The enthalpy is the state variable of the flow that defines the energy associated with the mass flow rate.
- Entropy (\(s\)) [kJ/C]: The entropy is a state variable of the flow that defines the disorder of the flow.
- Exergy (\(k\)) [kJ]: The exergy is a state variable of the flow that defines the potential of the flow to do work by reversible transformation that exchange only with the environment. Exergy is calculated by \(k=(h-T_a \cdot s)-(h_{a}-T_a \cdot s_{a})\). Note that \(h_a\) and \(s_a\) are the enthalpy and entropy of reference in the environment including the enthalpy and the entropy of formation.
- Temperature [°C]: The temperature is a state variable of the flow that defines the thermal state of the flow.
- Pressure [bar]: The pressure is a state variable of the flow that defines the mechanical state of the flow.
- Composition : defines the set of compounds that are present in the flow.
- Name: the name of the compound, will be the same name as the name used in the model
- Mass Partial flow: The mass partial flow of the compound in the reference flow.
- Molar partial flow: The molar partial flow of the compound in the reference flow.
- Chemical formula: The chemical formula of the molecule. The chemical formula is formulated to have the atomic composition of the molecule (i.e. CH4,H2O,CO2, etc.)
- Phase: The phase is a state variable of the flow that defines the physical state of the flow.
- Model: The model refers to the method to be used to characterise the state of the flow. This information is used of the location in the model does not allow for calculation. It will access the equation of state of the flow that defines the relationship between the state variables of the flow, knowing that a state is perfectly known when N+2 state variables are known, where N is the number of components of the flow.
- State: defines the set of values used to calculate the state (e.g. T,P) or P,x or P,h
Environmental impact: defines a link to a life cycle inventory model that characerises the scope 3 elementary flows associated to the identified flow.
Properties: defines the set of additional properties that characterise the flow (quality).

Develop the Block Flow Diagram of the process

Identify the list of processing steps needed to realise the process conversion.

Create a block flow diagram to visualize the transformation of raw materials to products.
Highlight unit operations (e.g., compression, reaction, separation) and their interconnections.

Creating a block flow diagram

It is recommended to use the SVG format edited by drawio. It is also recommended to add flows and temperature levels in the drawing. The use of ipese display tool will allow you to add problem definition values on the svg drawing.

Identify Key Operating Parameters

Your model will generate Key Sustainability Performance indicators. Some generic models are used to represent the impact of the production, including the impact of the operation and the value or impact of the mobilised assets of the process. It covers the following aspects:

Economic: refers to the value in different markets of the flows of the process connectors and the economic value of the invesment required to mobilise the assets.
Environmental: refers to the environmental impact of the flows and assets using Life Cycle environmental impact assessment methodologies
Social: refers to impact like maturity of the technology, work load, etc…

Collect infromation about: - List controllable variables (e.g., temperature, pressure, flow rates) that influence conversion efficiency in the model. - Define performance metrics (e.g., yield, energy efficiency, waste generation). Those are typical formula resulting from the data generated by the process model.

Defining key operating input parameters

Each variable is defined by:

Name:
Min:
Max:
Default Value:
Physical Unit:
Description:
Short Name:

Model the Process Unit

The process unit model is a mathematical operator, it can be as simple as a constant value or as complex as a flowsheet simulation engine. each model will calculate output values as a function of the input parameters. Please characerize the following:

Input Parameters: Compile all variables required to simulate the unit (e.g., feed composition, energy inputs).
Calculated Values: Compile the calculated values that are of interest to calculate the process unit interface. This is realised by selecting in the list of calculated values by the models the one that are necessary to calculate the process unit interface for the systemic integration. Output values will chracterize the exchange flows : materials (with their thermodynamic state) and energy flows as heat, electrcity or work.
The calculation engine: The calculation engine is used to generate the process data by solving the model. Calculation engine can be as simple as a simple formula or complex as a flowsheeting tool like aspen, gProms or vali.
The model data base: process model data base includes the structured data using the prprietary format for the calcualtion engine. This is where you flowsheet will be read, your input parameters will be send and the output values will be extracted.
Model Validity constraints: Include operational limits (e.g., maximum temperature, pressure drop) that will be used to check that the numerical results generated by the model are valid to represent the processing operation.

Defining Process model input and output parameters

Each variable is defined by:

Name:
Type:
- “Input” for values to be set by the user of the model
- “Output” for values calculated by the process model and extracted from the process model data base.
Min: Min and max values will be used for consistency check when using the process model.
Max:
Default Value: Default values are given to allow the generic use of the model
Physical Unit:
Description:
Short Name:
Location: defines the location of the data in the process model data base. This will be used to automatically collect the value generated by the calculation engine.

Processing units heat transfer interface

A process unit is a sub-system in the process (figure Figure 2). Similarily to the process model, it will define a mass and energy exchange interface with the specificity that the role of the heat will be explicitely defined.

Figure 2: Processing unit operation in a given industrial process

Based on the results of the models define the list of exchanges inside the prcoessing system, for each process unit identified you will define in particular the heat transfer needs as temperature enthalpy profile of the heat trasnfer that is needed, the electricity and the work needs.

Internal Mass Streams:
- Inputs: \(\dot{m}^{+}_{m}\) Raw materials, auxiliary chemicals, and utilities (e.g., water, air).
- Outputs: \(\dot{m}^{-}_{p}\) Products, by-products, and waste streams.
- Flow Rates: Quantify mass flow for each stream (kg/s or kmol/s).
- Composition and thermodynamic state: to thermodynamically characterize the flow

Adding mass connection to a process unit

The folllowing structure is used to define a mass or energy connector interface: - Name [string]: name of the connector - Production [kg/s]: flow for the reference size of the unit - fmin [kg/s]: minimum flow - fmax [kg/s]: maximum flow - Reference Mass flow rate: The mass flow rate is the reference mass flow rate of the connector.it is the mass that flows through the connector per unit of time. - Stream Location: define the location of the flow data in the process model data base. This will be used to automatically collect the thermodynamic characterisation of the flow. - Enthalpy (\(h\)) [kJ]: The enthalpy is the state variable of the flow that defines the energy associated with the mass flow rate.

Entropy (\(s\)) [kJ/C]: The entropy is a state variable of the flow that defines the disorder of the flow.
Exergy (\(k\)) [kJ]: The exergy is a state variable of the flow that defines the potential of the flow to do work by reversible transformation that exchange only with the environment. Exergy is calculated by \(k=(h-T_a \cdot s)-(h_{a}-T_a \cdot s_{a})\). Note that \(h_a\) and \(s_a\) are the enthalpy and entropy of reference in the environment including the enthalpy and the entropy of formation.
Temperature [°C]: The temperature is a state variable of the flow that defines the thermal state of the flow.
Pressure [bar]: The pressure is a state variable of the flow that defines the mechanical state of the flow.
Compounds : defines the set of compounds that are present in the flow.
- Name: the name of the compound, will be the same name as the name used in the model
- Mass Partial flow: The mass partial flow of the compound in the reference flow.
- Molar partial flow: The molar partial flow of the compound in the reference flow.
- Chemical formula: The chemical formula of the molecule. The chemical formula is formulated to have the atomic composition of the molecule (i.e. CH4,H2O,CO2, etc.)
Phase: The phase is a state variable of the flow that defines the physical state of the flow.
Model: The model refers to the method to be used to characterise the state of the flow. It will access the equation of state of the flow that defines the relationship between the state variables of the flow, knowing that a state is perfectly known when N+2 state variables are known, where N is the number of components of the flow.
State: defines the set of values used to calculate the state (e.g. T,P) or P,x or P,h
Properties: defines the set of additional properties that characterise the flow (quality).

Energy Streams:
- Work/Electricity \(\dot{E}^{+}_{energy}\): Specify power requirements (kW) for compressors, pumps, turbines or reactors.
- Heat Transfer:\(\dot{Q}^{+}_{T^{+}}\) Identify hot and cold streams, including inlet and target temperatures (\(T^{+}\)) and with the type of heat transfer involved (e.g phase and flows).

Adding heat transfer to a process unit

The folllowing structure is used to define a heat tranfer interface: - Name [string]: name of the heat transfer interface - Source_T [°C]: Temperature at the entrance of the heat transfer operation - Target_T [°C]: Temperature to be reached after the heat transfer operation - Source_Enthalpy [kW]: Enthalpy at the entrance of the heat transfer operation - Target_Enthalpy [kW]: Enthalpy to be reached after the heat transfer operation - DTmin_2 [°C]: Minimum temperature difference between the hot and cold streams - heat film transfer: [kW/m2/K]film Heat transfer coefficient - Description [string]: description of the heat transfer interface

5. Specify Equipment Requirements

Each equipment in the process will need to be sized to allow for the cost estimation and the associated CAPEX and environmental impact assessment:

Sizing parameters: Determine equipment dimensions resulting from the process model (e.g., reactor volume, heat exchanger area) that will be used for equipment sizing. The sizing function is associated to the equipment selected to realise the process operation.
Cost Estimation: Link equipment size to capital and operational costs, including environmental impact (e.g., CO₂ footprint). The cost estimation is typically resulting from an observation of market conditions in a given year under specific (i.e. geographical) conditions.

Adding an equipment to a process unit

Prepare the following information to add an equipment to the process unit - Name: name of the equipment - Type: Type of the equipment identified in the equipment sizing data base - Sizing: sizing parameters - Parameter: sizing parameter of the equipment from the equipment sizing data base - Lifetime: expected lifetime of the equipment - Material: type of construction material used - description: description of the equipment

6. Prepare for System Integration

Although models can be really diverse and use different types of calculation engines, the resulting process unit interface needs to be statndardized to contribute to the system integration. The system integration model will consider that for given input paramters of the units, the level of usage (capacity factor) of the units will be calculated to satisfy the systems needs. Your data needs therfore to be prepared with:

Standardized Format: Ensure the model outputs (mass/energy flows) match the system’s input requirements.
Compatibility Checks: Validate that the unit’s operating range aligns with system constraints.
Optimization Readiness: Provide flexibility to adjust parameters for system-wide optimization (e.g., energy recovery, waste minimization).