How to simulate yield reactor: modelling a reaction nobody has kinetics for

Pyrolysis, gasification and cracking share a problem: the feed is not a set of molecules with a stoichiometry, it is biomass or coal or a heavy residue, and there is no reaction network to write down. What you have instead is a measured product slate from a pilot run. The **yield reactor** (Aspen's RYield) is the unit op for exactly that case — you give it the slate, it gives you a stream. Here 100 mol/s of feed goes to 823 K and comes out as 112 mol/s of gas at a specified mass yield (31% CO₂, 28% water, 22% methane, 14% ethane, 5% hydrogen), for a **3.66 MW** heating duty. The mole count rises and the **mass does not**: the yields are normalised so the product mass equals the feed mass exactly, which is the entire contract of a yield reactor and the one thing it will not let you get wrong. **Be honest about what this is.** It has no kinetics, no equilibrium, no residence time and no temperature dependence of the slate — change the outlet temperature and the products do not shift, only the duty does. It is a way to carry a measured yield through a heat and material balance so the rest of the flowsheet is right; it predicts nothing about the reaction itself. If you have a rate law, use `kinetic_reactor`; if the system reaches equilibrium, use `gibbs_reactor`. Reach for this one when you have neither, which for solid-feed conversion is most of the time.

Frequently asked questions

What does the Yield reactor: modelling a reaction nobody has kinetics for model simulate?

Pyrolysis, gasification and cracking share a problem: the feed is not a set of molecules with a stoichiometry, it is biomass or coal or a heavy residue, and there is no reaction network to write down. What you have instead is a measured product slate from a pilot run. The **yield reactor** (Aspen's RYield) is the unit op for exactly that case — you give it the slate, it gives you a stream. Here 100 mol/s of feed goes to 823 K and comes out as 112 mol/s of gas at a specified mass yield (31% CO₂, 28% water, 22% methane, 14% ethane, 5% hydrogen), for a **3.66 MW** heating duty. The mole count rises and the **mass does not**: the yields are normalised so the product mass equals the feed mass exactly, which is the entire contract of a yield reactor and the one thing it will not let you get wrong. **Be honest about what this is.** It has no kinetics, no equilibrium, no residence time and no temperature dependence of the slate — change the outlet temperature and the products do not shift, only the duty does. It is a way to carry a measured yield through a heat and material balance so the rest of the flowsheet is right; it predicts nothing about the reaction itself. If you have a rate law, use `kinetic_reactor`; if the system reaches equilibrium, use `gibbs_reactor`. Reach for this one when you have neither, which for solid-feed conversion is most of the time.

Which thermodynamic method does it use?

The PENG-ROBINSON property package, over methane, co2, water, hydrogen, ethane — already selected. You can switch the method on the canvas before running.

Which unit operations are in the flowsheet?

It chains PYRO. 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. Yield reactor: modelling a reaction nobody has kinetics for runs entirely in your browser on MaximaLabs — free, no install, no license. Open the model to load it live and run the deterministic solver.