How to simulate batch campaign: a batch step inside a continuous flowsheet

Fine chemicals and pharma run batches, but a flowsheet is written in mol/s. These two unit ops reconcile that: they integrate the real batch physics over the batch, then report the products as the RATE that campaign delivers, so a batch step sits inside a continuous flowsheet the way a plant actually runs one. The **batch reactor** esterifies ethanol with acetic acid to ethyl acetate and water. It reaches **63.2% conversion** and stops, and that number is not a specification — it is the equilibrium. The reaction is reversible with an equilibrium constant of 4 (the forward and reverse pre-exponentials are given as 5.0e4 and 1.25e4), and solving `K = x(0.10+x)/(0.45-x)^2 = 4` for an equimolar charge carrying 10% water gives an extent of 0.285, which is 63.3% of the acid. Fischer esterification really does plateau there; a model that ran to completion would be describing a different reaction. **Turnaround time costs throughput exactly as reaction time does.** Two hours of reaction plus one hour of turnaround is a **3-hour cycle** and **2922 batches a year**, and the reactor is only reacting for **67%** of the time it is occupied. That fraction is the number that decides whether you need a second reactor, and it is invisible to a steady-state model. The **batch still** then takes the crude and recovers the ethyl acetate — the distillate comes off essentially pure, from a pot that started at 28.5 mol% ester — on its own longer 4-hour cycle, so the two units run at genuinely different campaign rates. **Bounded:** the flowsheet sees each unit's CYCLE AVERAGE, not the transient. A real plant has a surge tank between these two smoothing the pulses, and neither the concentration profile during the batch nor the still's changing overhead composition is visible downstream.

Frequently asked questions

What does the Batch campaign: a batch step inside a continuous flowsheet model simulate?

Fine chemicals and pharma run batches, but a flowsheet is written in mol/s. These two unit ops reconcile that: they integrate the real batch physics over the batch, then report the products as the RATE that campaign delivers, so a batch step sits inside a continuous flowsheet the way a plant actually runs one. The **batch reactor** esterifies ethanol with acetic acid to ethyl acetate and water. It reaches **63.2% conversion** and stops, and that number is not a specification — it is the equilibrium. The reaction is reversible with an equilibrium constant of 4 (the forward and reverse pre-exponentials are given as 5.0e4 and 1.25e4), and solving `K = x(0.10+x)/(0.45-x)^2 = 4` for an equimolar charge carrying 10% water gives an extent of 0.285, which is 63.3% of the acid. Fischer esterification really does plateau there; a model that ran to completion would be describing a different reaction. **Turnaround time costs throughput exactly as reaction time does.** Two hours of reaction plus one hour of turnaround is a **3-hour cycle** and **2922 batches a year**, and the reactor is only reacting for **67%** of the time it is occupied. That fraction is the number that decides whether you need a second reactor, and it is invisible to a steady-state model. The **batch still** then takes the crude and recovers the ethyl acetate — the distillate comes off essentially pure, from a pot that started at 28.5 mol% ester — on its own longer 4-hour cycle, so the two units run at genuinely different campaign rates. **Bounded:** the flowsheet sees each unit's CYCLE AVERAGE, not the transient. A real plant has a surge tank between these two smoothing the pulses, and neither the concentration profile during the batch nor the still's changing overhead composition is visible downstream.

Which thermodynamic method does it use?

The NRTL property package, over ethanol, acetic_acid, ethyl_acetate, water — already selected. You can switch the method on the canvas before running.

Which unit operations are in the flowsheet?

It chains RX, Still. Every block is a real, solvable unit operation you can reconfigure, add to, or remove.

Do I need to install software or buy a license?

No. Batch campaign: a batch step inside a continuous flowsheet runs entirely in your browser on MaximaLabs — free, no install, no license. Open the model to load it live and run the deterministic solver.