Open Tools · Chemical, reaction engineering
Ratelab: free online reaction kinetics workbench
Ratelab is a free, browser-based workbench for chemical reaction kinetics and ideal reactor design. Write a reaction network as equations, choose mass-action or power-law rate laws with Arrhenius temperature dependence, and simulate supported batch, CSTR, PFR and semibatch workflows with stiff implicit integrators, including adiabatic and heat-exchange operation. Gas-phase transient simulation is unsupported; gas CSTR analysis uses the steady-state path.
Beyond simulation it searches for steady states of a nonisothermal CSTR and reports their stability when resolved, sizes reactors and series arrangements from Levenspiel plots, fits rate laws to concentration data with confidence intervals, estimates shared parameters from several experiments, runs local and variance-based sensitivity analysis and a residual bootstrap, and reports yield, selectivity and residence-time distributions. Documents stay on your device. Unavailable laboratory validation stays PENDING SOURCE.
What Ratelab can do
- Reaction networks with mass-action, power-law and reversible rate laws
- Stiff implicit integration with analytic Jacobians for supported reactor workflows
- Nonisothermal CSTR steady states and resolved linear stability
- Levenspiel sizing, reactors in series and CSTR-PFR combinations
- Rate-law fitting and joint multi-experiment kinetic fitting
- Residual bootstrap, sensitivity, yield, selectivity and residence-time distributions
- CSV and Markdown exports with open project files
How we verify Ratelab
Ratelab is checked against 217 independent reference cases. Where a reference answer exists you can run every check yourself on the Verify page, and the Ratelab user guide documents every feature and limitation.
The Verify view runs the tool's own reference suite in your browser, case by case, with progress, and shows for each case what is checked, the reference with its citation, the computed value, the difference, the tolerance and PASS or FAIL. Some comparisons recompute the same formula and check transcription only; separate independent tests are documented in docs/RIGOR_REGISTER.md. The same cases (engine/verification/cases.ts) are run by the automated test suite, so what you see is what CI checks.
Ratelab is part of Open Tools, the free engineering tools that run in your browser.
Professional use. Results are for education and preliminary design. They must be checked by a qualified professional, and they are not a substitute for code-compliant design or licensed engineering judgement.