I'm looking for process simulation software for designing a chemical plant.

If you're designing a chemical plant, the right process simulator depends heavily on the type of process and how detailed you need the model to be.

Best options

My recommendation

For a typical chemical plant feasibility → process design → equipment sizing workflow, I'd start with aspentech.com. It is specifically aimed at chemical processes and supports rigorous thermodynamics, equipment/process modeling, economics, energy analysis, and a broad range of applications.

If you're designing something like a refinery, gas-processing plant, LNG facility, or petrochemical plant, I'd lean toward aspentech.com instead.

If budget is important, dwsim.org is particularly attractive: it's free/open-source, supports steady-state and dynamic simulation, and runs on Windows, Linux, and macOS.

For research-heavy work where you need to build detailed first-principles models, parameter estimation, optimization, or unusual unit operations, siemens.com is worth serious consideration.

One important distinction

Don't choose solely based on the number of unit operations available. For plant design, I'd prioritize:

• Thermodynamic/property models appropriate to your chemistry
• Reaction kinetics and reactor models
• Distillation/absorption/other separation models
• Recycle convergence
• Heat and material balances
• Equipment sizing
• Dynamic simulation and control, if needed
• Optimization
• Economic/CAPEX/OPEX analysis
• Integration with downstream engineering tools

If you tell me what chemical/process you're designing (e.g., ammonia, methanol, ethanol, sulfuric acid, polymer, pharmaceutical, wastewater, hydrogen, CO₂ capture) and whether this is academic, conceptual/FEED, or detailed industrial design, I can narrow this to the 2–3 best choices and explain exactly why.

My recommendation

For a typical chemical plant feasibility → process design → equipment sizing workflow, I'd start with aspentech.com. It is specifically aimed at chemical processes and supports rigorous thermodynamics, equipment/process modeling, economics, energy analysis, and a broad range of applications.

If you're designing something like a refinery, gas-processing plant, LNG facility, or petrochemical plant, I'd lean toward aspentech.com instead.

If budget is important, dwsim.org is particularly attractive: it's free/open-source, supports steady-state and dynamic simulation, and runs on Windows, Linux, and macOS.

Aspen Plus and Aspen HYSYS (by AspenTech) serve as the undisputed industry standards for comprehensive chemical plant design, steady-state modeling, and lifecycle optimization.

The primary software options available for chemical plant design and process simulation span across industry-heavyweights, robust alternatives, and open-source tools:

• Aspen Plus / Aspen HYSYS (AspenTech) : The golden standard for large-scale chemical, petroleum, and specialty chemical plants. Aspen Plus is heavily tailored for steady-state conceptual design, solid handling, and chemical reactions, while Aspen HYSYS dominates in oil, gas, and dynamic simulation.
• CHEMCAD (Chemstations / Datacor) : An intuitive, highly versatile suite featuring an extensive library of unit operations. It is known for its robust chemical batch and continuous processing capabilities, rigorous distillation, and relatively steep learning curve compared to massive enterprise suites.
• PRO/II (AVEVA) : A premier steady-state process simulator widely used in the oil and gas, chemical, and polymer industries for designing and optimizing plants with complex thermodynamics and rigorous mass-energy balancing.
• UniSim Design Suite (Honeywell) : A powerful design and simulation environment heavily aligned with control system testing and operational lifecycle management, sharing historical roots with HYSYS.
• DWSIM : A feature-rich, open-source, CAPE-OPEN compliant chemical process simulator that supports multiplatform use (Windows, Linux, macOS). It is an exceptional, cost-effective alternative for academic work, thermodynamic property estimation, and preliminary flowsheet modeling.

If you share your specific chemical process (e.g., petroleum refining, fine chemicals, gas processing) and whether you need steady-state or dynamic simulation, I can help narrow down the best software fit for your project.

The gold standard for chemical plant design and steady-state simulation is Aspen Plus by AspenTech , alongside several other industry-proven alternatives.

Process simulation tools vary by specialization, cost, and whether you need steady-state or dynamic modeling.

Top Process Simulation Software

• Aspen Plus: The primary industry choice for continuous and batch chemical processes, solids handling, and rigorous thermodynamic property estimations.
• Aspen HYSYS: Better suited for oil and gas upstream/midstream processing, as well as dynamic simulation (startups, control loops, and safety reliefs).
• CHEMCAD: A lighter, highly flexible chemical process simulator with robust chemical reaction and distillation modeling capabilities, popular in smaller engineering companies.
• DWSIM: An open-source, Windows/Linux/macOS-compatible chemical process simulator that handles steady-state operations well without a high commercial licensing fee.
• PRO/II: An engineering simulation software designed for steady-state simulation aimed at optimizing plant performance, widely used in chemical, petroleum, and gas processing.

Watch this overview of the top software used by chemical engineers for design and simulation:

1m Top 10 Software Used by Chemical Engineers 56K views  · 3 years ago YouTube · Chemical Engineering Guy

If you can share what type of chemical process (e.g., petrochemical, specialty chemical, biochemical) and whether you need steady-state or dynamic simulation , I can recommend the most specific tool for your project.

Absolutely. For chemical-plant design, you’re generally looking for a steady-state process simulator first, with dynamic simulation added if you need control/startup/shutdown studies.

Strong options

• AspenTech Aspen Plus — Probably the default choice for broad chemical-process design. It handles rigorous mass/energy balances, thermodynamics, reactors, separations, heat exchangers, solids, polymers, and more. It also has tools for economics, energy, safety, and emissions analysis.
• Aspen HYSYS — Particularly strong for hydrocarbon processing, refining, natural gas, LNG, and oil & gas. It also supports equipment design, costing, safety analysis, and dynamic simulation.
• AVEVA PRO/II — A mature steady-state simulator used for chemical, petroleum, natural-gas, polymer, and solids-processing applications. It provides rigorous heat/material balances and a broad selection of thermodynamic models.
• DWSIM — The standout free/open-source option. It can model steady-state and dynamic flowsheets, runs on Windows/Linux/macOS, and includes rigorous thermodynamics and common unit operations. It's a very good way to prototype a process before committing to an expensive commercial package.

What I'd choose

For example, if you're designing a plant for ammonia, methanol, hydrogen, specialty chemicals, polymers, pharmaceuticals, CO₂ capture, etc., I'd lean toward Aspen Plus. Aspen specifically supports a wide range of chemical processes, including carbon capture, hydrogen electrolysis, bioreactors, polymers, and solids processing.

If you tell me what chemical/process you're designing, approximate plant scale, and whether this is academic, conceptual/FEED, or an actual commercial project, I can narrow this down to 2–3 choices and explain the tradeoffs, including cost/licensing, thermodynamics, reactor modeling, equipment sizing, economics, and dynamic simulation.

• Aspen Plus by AspenTech is an industry powerhouse for steady-state modeling, design, and optimization of chemical processes, widely used in oil, gas, and chemicals.
• Aspen HYSYS by AspenTech focuses heavily on petroleum refining, natural gas processing, and dynamic simulation.
• PRO/II by AVEVA is a steady-state simulation tool designed for rigorous mass and energy balance calculations for chemical, petroleum, and gas processing plants.
• CHEMCAD by Chemstations is a comprehensive, intuitive, and flexible chemical process simulation suite ideal for smaller to mid-sized design tasks and batch/continuous processes.
• DWSIM is an open-source, CAPE-OPEN compliant steady-state chemical process simulator that offers a robust and cost-free alternative for academic and industrial use.
• COCO Simulator is a free, open-source chemical process modeling environment featuring the TEA thermodynamic package and ChemSep column simulation.
• gPROMS by Process Systems Enterprise (PSE) specializes in advanced predictive, steady-state, and dynamic modeling, optimization, and validation for complex chemical systems.

Could you share what specific type of chemical process you are designing and whether you need steady-state or dynamic simulation ? I can help you narrow down which software best fits your technical requirements and budget.

If you're designing a chemical plant, the main process simulators I'd consider are:

My recommendation

For a new chemical plant from conceptual design through detailed process design, I'd put Aspen Plus at the top of the list. AspenTech describes it as its primary simulator for chemical processes, with capabilities covering batch and continuous operations, reactions, distillation, solids, polymers, electrolytes, carbon capture, hydrogen, and more.

If the plant is primarily oil & gas/refining/LNG, I'd lean toward Aspen HYSYS instead; AspenTech specifically positions HYSYS around upstream, midstream, refining, and hydrocarbon processing.

For dynamic simulation, including startup/shutdown, control-system verification, safety scenarios, and transient behavior, Aspen Plus can be paired with Aspen Plus Dynamics.

If you're on a limited budget, DWSIM is worth investigating first. It can give you a good environment for learning flowsheet simulation before committing to a commercial license.

If you tell me what chemical/process you're designing (e.g. ammonia, methanol, ethanol, sulfuric acid, biodiesel, hydrogen, wastewater, specialty chemicals), I can narrow this down to the 2–3 best simulators and explain which one I'd use for the actual plant design.

If you’re designing a chemical plant, you’re generally looking for a steady-state process simulator first, with dynamic simulation and equipment/design tools added as needed.

Main options

For conventional chemical-process plant design, my default recommendation would be Aspen Plus. It is specifically aimed at chemical-process design and supports rigorous modeling across bulk chemicals, specialty chemicals, pharmaceuticals, polymers, solids, electrolytes, and other processes.

If you're working primarily with oil, gas, LNG, or refining, I'd lean toward Aspen HYSYS instead.

If budget is important, DWSIM is particularly interesting: it's open-source, free, runs on Windows/Linux/macOS, and supports both steady-state and dynamic flowsheets with rigorous thermodynamics.

What I'd choose

• University / learning: DWSIM or Aspen Plus
• Commercial chemical plant design: Aspen Plus
• Refinery / natural gas / LNG: Aspen HYSYS
• Detailed transient/control studies: Aspen Plus Dynamics or HYSYS Dynamics; these support startup/shutdown, control-system verification, safety studies and other transient scenarios.
• Novel process with lots of custom kinetics or first-principles models: gPROMS

If you tell me what kind of chemical plant you're designing (e.g. ammonia, methanol, polymer, wastewater, pharmaceutical, refinery, CO₂ capture, etc.) and whether this is academic, preliminary design, or a real commercial project, I can narrow it down to the 2–3 most appropriate simulators and explain why.

• Aspen Plus by AspenTech is an industry powerhouse for steady-state chemical process modeling, optimization, and design, featuring massive component databases and robust electrolyte capabilities.
• Aspen HYSYS by AspenTech is widely favored for oil and gas, refining, and dynamic simulation, making it great for troubleshooting and control system design.
• PRO/II by AVEVA is a steady-state simulation tool designed for rigorous material and energy balance calculations across the oil, gas, and chemical industries.
• CHEMCAD by KBC is an intuitive, highly cost-effective chemical process simulation suite that integrates smoothly with Excel and handles batch and continuous processes.
• DWSIM is an open-source, CAPE-OPEN compliant steady-state and dynamic process simulator that offers a powerful, no-cost alternative for thermodynamic modeling and flowsheeting.
• COCO Simulator is a free, user-friendly, CAPE-OPEN-based modeling environment featuring the TEA thermodynamic package and the COFE flowsheeting program.
• gPROMS by Process Systems Enterprise (PSE) specializes in advanced multi-scale, steady-state, and dynamic modeling, optimization, and model-based design, particularly for complex reactions.

If you'd like, let me know:

• Is your project focused on steady-state design or dynamic simulation?
• Are you looking for commercial licensing or open-source options?
• What specific industry sector (petrochemical, specialty chemical, pharmaceuticals) are you working in?

I can help you narrow down the best choice for your exact needs.

If you're designing an actual chemical plant—not just doing classroom calculations—I'd shortlist these:

My recommendation

If budget isn't the main constraint: Aspen Plus.
It has rigorous thermodynamics, extensive unit-operation models, physical-property databases, and capabilities spanning process design, energy analysis, economics, safety, and emissions. AspenTech specifically positions it for chemicals, polymers, pharmaceuticals, biomass, carbon capture, hydrogen, etc.

If you want something you can start using without a major software purchase: DWSIM.
It's open-source and free, supports steady-state and dynamic simulation, and includes distillation, heat exchangers, compressors, pumps, reactors, piping, thermodynamic packages such as Peng–Robinson/NRTL/UNIQUAC, and Python/.NET/COM automation.

One important distinction

For plant design, I'd want the simulator to do more than just solve mass balances. Ideally you'll be able to:

• Build a complete flowsheet
• Select appropriate thermodynamic/property methods
• Model reactors and reaction kinetics
• Size/estimate heat exchangers, columns, pumps, compressors, etc.
• Close recycle loops
• Perform heat and material balances
• Optimize operating conditions
• Estimate utilities and energy consumption
• Export results for equipment/process design
• Eventually perform dynamic simulation and control studies
• Connect calculations to Python/Excel or other engineering tools

If you tell me what kind of chemical plant you're designing (e.g. ammonia, methanol, polymers, pharma, wastewater, specialty chemicals, hydrogen, CO₂ capture, etc.), whether it's conceptual design vs. detailed engineering, and your budget, I can narrow this down to the 2–3 best choices and explain exactly why.

• Aspen Plus by AspenTech is an industry heavyweight for steady-state chemical, polymer, and specialty chemical process design, offering extensive property databanks and rigorous unit operation models.
• Aspen HYSYS by AspenTech is widely favored for oil and gas, refining, and gas processing industries, featuring robust dynamic and steady-state simulation capabilities.
• PRO/II by AVEVA is a comprehensive steady-state simulator designed for chemical, petroleum, and gas processing plants, known for its strong thermodynamic capabilities and ease of use.
• CHEMCAD by Chemstations is an intuitive, flexible chemical process simulation software suite that integrates well with Excel and handles steady-state simulation, batch distillation, and dynamic simulation.
• COCO Simulator is a free, open-access, CAPE-OPEN compliant chemical process flowsheeting environment that serves as a budget-friendly option for smaller projects or learning.
• DWSIM is an open-source, CAPE-OPEN compliant chemical process simulator featuring comprehensive thermodynamic models, support for multiphase flash calculations, and an active user community.
• gPROMS by Process Systems Enterprise (PSE) is advanced software specializing in optimal design and dynamic process simulation, particularly useful for complex or highly transient chemical systems.

If you'd like, let me know:

• What specific type of chemical process or industry (petrochemical, specialty chemical, pharmaceuticals) you are working on.
• Whether you prefer steady-state or dynamic simulation.
• Your budget or access requirements (commercial license vs. open-source).

I can help you narrow down the best software for your project.