Chemical & Materials
Mass Balance Lab
Recycle loops are where mass balances get hard: you can't compute the streams left-to-right because the recycle feeds back into the start, so every flow has to be solved at once. Drag the feed and the two split fractions and the whole flowsheet re-solves (through a real linear solver). Turn the recycle up and the internal flow balloons far above the fresh feed — yet the two product streams always still add up to the feed. That's conservation of mass, and the 'does it close?' check every chemical engineer runs.
153.8
Internal flow S1
53.8
Recycle
100.0
Products out
✓ yes
Balance closes
The recycle couples the whole flowsheet — you can't just compute streams left to right, you have to solve them together. Crank the recycle up and the internal flow S1 balloons far above the feed, yet the products S2 + S4 always still sum to F. That's conservation of mass, and the "does it close?" check you run on every balance.
How to use this simulation
Recycle loops are where mass balances get hard: you can't compute the streams left-to-right because the recycle feeds back into the start, so every flow has to be solved at once. Drag the feed and the two split fractions and the whole flowsheet re-solves (through a real linear solver). Turn the recycle up and the internal flow balloons far above the fresh feed — yet the two product streams always still add up to the feed. That's conservation of mass, and the 'does it close?' check every chemical engineer runs.
Everything runs in your browser — no sign-up, no download. Change a value and the result updates instantly, so you can build a feel for how each input shapes the outcome. It pairs with Crameleon's practice exams and step sheets when you want to go from intuition to working the problems.