Purpose
Use modeling to resolve the question that controls the next decision.
A process model should do more than reproduce a flowsheet. It should expose the assumptions, interactions, sensitivities, and data gaps that determine whether a process can meet its technical and commercial objectives.
ONB Engineering develops fit-for-purpose models ranging from early feasibility calculations to integrated steady-state flowsheets, reactor models, digital twins, and targeted CFD or CPFD studies. Model complexity is matched to the decision and the quality of available data.
When this service is useful
Evaluate yield, purity, conversion, throughput, energy use, and operating constraints.
Separate critical variables from secondary variables through sensitivity and scenario analysis.
Identify the parameters and experiments that most reduce uncertainty before scale-up.
Locate capacity, separation, utility, heat-integration, and reactor-performance constraints.
Scope and capabilities
Integrated process simulation
Process model flowsheets (Aspen Plus, Aspen HYSYS or other), thermodynamic-method selection, recycles, utilities, and separation systems.
Reactor and kinetics models
Reaction networks, rate expressions, parameter estimation, residence-time effects, and reactor-performance calculations.
Sensitivity and uncertainty
Operating windows, scenario analysis, parameter ranges, uncertainty propagation, and decision-relevant tradeoffs.
Digital twins and model reduction
Fit-for-purpose models for design studies, monitoring, optimization, or integration with broader decision tools.
CFD and CPFD studies
Study definition and analysis for fluid flow, heat and mass transfer, multiphase behavior, and reactor hydrodynamics.
Model review and validation
Independent audit of assumptions, inputs, convergence, calibration, validation evidence, and intended model use.
Typical deliverables
- Documented model files and calculation basis
- Thermodynamic and reaction-method rationale
- Mass and energy balances
- Key assumptions and data-quality assessment
- Sensitivity and scenario results
- Operating-window or bottleneck analysis
- Validation comparison and residual gaps
- Recommended tests or next modeling steps
A model is only as useful as its assumptions.
ONB Engineering documents where inputs come from, which assumptions control the result, what has been validated, and where the model should not be relied upon. This makes the analysis reviewable and useful for engineering, management, investors, vendors, or future project teams.
Representative applications
Frequently asked questions
Does every project require a full Process model (e.g. Aspen Model)?
No. The appropriate model may be a structured calculation, reactor model, spreadsheet, process modeling flowsheet, CFD study, or combination. The model should be no more complex than the decision requires.
Can ONB Engineering work with incomplete laboratory data?
Yes, provided the uncertainty is made explicit. Early-stage work often uses bounded assumptions and sensitivity analysis to identify which missing data materially affect the decision.
Can an existing model be reviewed instead of rebuilt?
Yes. ONB Engineering can audit an existing model’s inputs, thermodynamics, reaction basis, convergence, validation, and suitability for its intended use.
Will the client receive the model files?
Model ownership and file transfer can be defined in the project scope. ONB Engineering’s standard approach is to make deliverables usable and traceable for the client.