Free, browser-based process simulation
A real process simulator.
In your browser. Free to learn.
Build and converge industrial flowsheets with a built-in AI tutor. Get the rigour of professional simulation software without license fees or installs.
Then publish on LensaSim Connect, where employers and the public can open, fork, and run the flowsheets you build.
No installs No credit card Transparent, inspectable methods
A real simulator, not a toy
The same workflow you would learn on industry tools — seven linked environments from Properties and Simulation through Energy, Economics, Safety and Dynamics, with sequential-modular solving, property packages and design-grade methods.
Flowsheeting canvas
Drag-and-drop equipment with real PFD symbols, connect streams, and solve — 33 unit operations from pumps and exchangers to rigorous distillation, absorbers, kinetic reactors, a full solids line and extractive-metallurgy cells.
Thermodynamic engines
Ideal, Peng-Robinson and SRK packages free for everyone; NRTL activity coefficients on Pro. A 3,400+ component databank — fluids and minerals — built from validated, openly licensed data.
Recycle convergence
Automatic tear-stream selection with Wegstein acceleration, a live convergence monitor, and user-selectable tear streams — learn how real solvers actually work.
Design-grade unit models
Fenske-Underwood-Gilliland shortcut distillation and a rigorous Wang-Henke MESH column, kinetic reactors with real reaction heat, isentropic compressors and counter-current exchangers with LMTD/UA.
Solids engine
Crushers (Bond's law), screens, cyclones, filters, dryers and kilns with particle-size distributions — model a calcination or ore line, not just vapor and liquid.
Dynamics
Take the converged steady state into time: size the vessels, add PID controllers and disturbances, and integrate a stiff DAE system with a real implicit solver. Every block on the palette carries into dynamics, and the ones that cannot say why.
Energy & Safety
Pinch analysis with composite curves, ΔTmin targeting and named heat-recovery opportunities — plus stream flammability and toxicity, relief sizing and a HAZOP worksheet.
AI process assistant (Pro)
Claude-powered guidance: interpret results, debug convergence, choose property packages, and estimate missing property data with clearly-labeled methods and uncertainty.
Techno-economic analysis (Pro)
A full Economics environment: equipment sizing from the converged balance, CAPEX with industry-standard module costing, utility-based OPEX, NPV/IRR profitability with sensitivity — and a printable TEA report.
LensaSim Connect
Anyone can say they can model a column
You can hand someone the flowsheet and let them press Run. Publish a design to Connect and it becomes a working artefact — openable, forkable, and re-solvable by a hiring manager, a lecturer or your own boss, on any browser, with no software to install.
Proof of work, not a claim
Every published design carries its own flowsheet. Fork & run opens it in a live simulator and solves it again from scratch — the reviewer sees the converged result, not a screenshot of one.
A profile that is a portfolio
A public page at your own handle: what you build, what people asked about it, and who follows your work. One link on a CV, an application or a performance review.
Competencies, evidenced
Skills on your profile say where they came from — demonstrated in published work, or self-declared and labelled as such. Nothing is quietly upgraded into a credential it did not earn.
Verifiable certifications
Server-graded credentials, each with a public verification link a recruiter can check without taking your word for it — or ours.
Review in the open
Threaded discussion under every design. Real engineers point out the property package that will not hold for your mixture, or the stage count worth changing — before a marker or an interviewer does.
Found by people hiring
Mark yourself open to work and appear in the talent directory, where employers search by the competencies your published work actually shows.
Learn it, then teach it
A tutor-style learning layer for secondary school, university and corporate training — and the tools for instructors to run a whole class on it.
Guided lessons
Bite-size lessons that explain a concept, ask you to predict, have you build it in the real simulator, then reflect — levelled for secondary, university and corporate learners.
Progress & certifications
Track lessons, keep a daily streak and earn badges as you complete each level — then earn a verifiable, server-graded certification when you're ready for a credential.
Classrooms & auto-grading
Instructors create a class, share a join code, and set assignments with weighted checks and concept quizzes that the server grades by re-solving the real flowsheet. Gradebook, analytics and feedback included.
Why LensaSim exists
Commercial process simulators are extraordinary tools — and extraordinarily expensive. For too many universities, license fees put them out of reach, so students graduate without ever touching the software their profession runs on.
LensaSim is built to close that gap: a serious, browser-based simulator that is free at the point of learning, with transparent methods students can inspect, guided lessons that teach, and AI assistance where proprietary databanks would otherwise be the barrier.
And access alone was never the whole gap. An engineer who has learned the work still has to show it. Connect is the other half of that: somewhere the thing you built is public, runnable and attributable to you — so the evidence travels with the skill.
Students & self-learners
Learn flowsheeting, thermodynamics and separations on the free tier — genuinely, not as a crippled demo.
Universities & instructors
Run whole cohorts through auto-graded assignments, a gradebook and shared flowsheets with campus licensing.
Corporate training
Onboard graduate engineers with guided, realistic exercises and verifiable certifications before they touch production tools.
Early-career engineers
Graduate without a portfolio and you compete on adjectives. Publish the work instead, and let it be opened and run.
Researchers
Rapid conceptual studies, screening calculations and teaching demos with exportable results.
Free where it teaches. Paid where it costs.
The simulation engine runs in your browser, so simulating is free — forever. Paid plans fund the AI assistance, storage and support that keep LensaSim sustainable.
Student (Free)
A real process simulator, free forever.
$0
- ›A daily taste of the AI Process Assistant (5 messages/day)
- ›Full flowsheeting canvas with up to 15 unit operations
- ›All 33 unit operations incl. rigorous & shortcut distillation, absorbers, kinetic reactors, a solids line and extractive-metallurgy cells
- ›Ideal (Raoult), Peng-Robinson and SRK property packages
Campus & Enterprise
Seat-based licensing for schools, universities and training teams.
Custom
- ›Everything in Pro, for every seat
- ›Separate teacher and student seat pools, sized to your cohort
- ›Members join automatically with your verified email domains — or an invite allowlist for personal addresses
- ›Admin dashboard: manage members, watch seat usage, promote teachers
Ready to build your first flowsheet?
No installs, no license fees — open the simulator and run a real process in minutes, or start with a guided lesson.