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Schema Reference

The Standard Flowsheet Format (SFF) is a JSON document strictly adhering to our JSON schema structure. This page breaks down the core sections of the SFF schema in human-readable terms to help developers quickly understand its structure.

Core Properties

Every valid SFF JSON object contains four essential properties at its root:

  1. metadata: Contextual data about the process simulation.
  2. units: The unit operations (nodes).
  3. streams: Process streams connecting the units (edges).
  4. utilities: Global heating, cooling, and power utilities used by the process.
  5. chemicals: A list of pure chemical components involved.

Metadata

The metadata object provides high-level information about the process flowsheet, versions, and economic settings.

  • sff_version: The version of SFF used (e.g., "1.0"). (Required)
  • TEA_currency: The currency used in the techno-economic analysis, typically "USD".
  • TEA_year: The baseline year used for calculating costs. (Required)
  • source_doi: A digital object identifier pointing to the publication where the process was introduced.
  • process_title: Title of the process flowsheet.
  • product_name: Primary product being manufactured.
  • organism: Organism used for bioproduction, if applicable.
  • flowsheet_designers: Authors who designed the simulation.

Chemicals

The chemicals array defines the chemical species available in the simulation. Each chemical must have: - id: A unique string identifier. - registry_id: A standard chemical identifier, like a CAS number or SMILES string.

Utilities

The utilities object is broken down into three main categories of global utilities:

  • heat_utilities: Heating and cooling utility types (e.g., "high-pressure steam"). Each details its temperature, pressure, regeneration and heat transfer prices, composition, and results unit.
  • power_utilities: Electrical utility types (e.g., "marginal electricity"), listing their electricity price.
  • other_utilities: Alternative utilities (e.g., combustion-based like "natural gas") with parameters similar to heat utilities.

Units (Nodes)

The units array contains all operational nodes of the process graph (e.g., reactors, distillation columns). Each unit object includes:

  • id: A unique string identifying this particular unit. (Required)
  • unit_type: A description indicating the kind of operation (e.g., "Distillation"). (Required)
  • design_input_specs: Essential design specifications needed to simulate this unit.
  • design_simulation_method: The analytical or computational methodology applied to simulate the unit (e.g., "McCabe-Thiele").
  • thermo_property_package: Defines how thermodynamic parameters (mixture, gamma, phi, PCF) were estimated.
  • reactions: Detailed definitions for chemical or biological reactions taking place inside the unit, indicating parallel indices, conversions, and target reactants.
  • design_results: Generated metrics for the operation of this unit.
  • purchase_costs & installed_costs: Itemized economic data detailing the cost of this particular unit operation.
  • utility_consumption_results & utility_production_results: Realized consumption and generation of power/heat per utility type (linking back to the IDs declared in utilities).

Streams (Edges)

The streams array maps out the connectivity of the flowsheet, defining how materials flow from one unit to another.

  • id: A unique string identifying the stream. (Required)
  • source_unit_id: The ID of the originating unit operation. (Required)
  • sink_unit_id: The ID of the receiving unit operation. (Required)
  • stream_description: A qualitative description (e.g., "Make-up solvent").
  • price: Cost per quantity of the stream material (e.g., $/kg).
  • stream_properties: A detailed block containing strictly required state information:
    • total_mass_flow
    • total_volumetric_flow
    • temperature
    • pressure
    • total_molar_flow (optional)
    • composition: An array defining the phase, component name (linking to the chemicals array IDs), and exact mol fraction.