Mass Balance Calculator

Waste Flow Rate comes from the overall mass balance -- total mass in (feed plus recycle) minus the product flow rate -- which is purely a matter of flow rates, not concentrations. Feed Concentration, Product Concentration, and Recycle Concentration only enter the separate component mass balance, which determines Waste Concentration, Conversion, and Overall Yield instead.

The overall mass balance tracks total mass regardless of composition: everything entering a unit (feed plus recycle) must equal everything leaving (product plus waste), since mass can't be created or destroyed. The component balance tracks just the key species you're interested in, using each stream's concentration to follow how much of that specific component ends up in the product versus the waste.

That combination is physically inconsistent -- a real process can't output more total mass than it takes in -- so this calculator floors Waste Flow Rate at zero instead of returning a negative figure. It does not separately warn you that the inputs are inconsistent, so if you see a zero Waste Flow Rate alongside a large Product Flow Rate, it's worth double-checking that your feed, recycle, and product numbers are actually consistent with each other.

Recycle Rate and Recycle Concentration add mass back into the process, effectively increasing the total material available (feed plus recycle) beyond the fresh feed alone. Setting Recycle Rate to zero removes the recycle loop entirely, reducing the calculation to a simple feed-in, product-and-waste-out balance with no material being returned to the process.

Both are measured against the same fresh-feed key component, but they account for the recycle stream differently. Overall Yield counts all of the key component that ends up in the product, regardless of whether it came from fresh feed or from material that was already recycled back through the process. Conversion nets out the portion of that product that's just recycled material passing through again, so it reflects only how much of the fresh feed was truly converted. With no recycle (Recycle Rate = 0), the two numbers are identical; as recycle increases, Overall Yield can look higher than Conversion because it's crediting recirculated material as if it were newly processed.