Octane and vapour pressure do not blend linearly, component properties drift and analysers report only every half hour, so recipes are set conservatively and grades are over delivered on every blend. Physics informed property models and a recipe agent take out the giveaway while holding every grade specification.
All case studies
blend components combined and balanced at the header, from reformate and alkylate to butane and ethanol
octane prediction error of the property models against the plant analysers, so recipes are tested in software first
to recompute a full on spec recipe online as component qualities move and grades are switched
Gasoline blending is nonlinear. Octane and vapour pressure do not blend linearly by volume, so a finished property cannot be read off from a simple weighted average of the components. Component properties also drift as upstream units move and feedstocks change, and analysers report only every half hour. Because the true blend behaviour is hard to predict, recipes are set conservatively and grades are over delivered on octane and on vapour pressure. That margin is value given away on every blend. When a recipe still lands off spec, as when a component is switched, the blend has to be corrected or reblended, which consumes capacity and raises cost further.
| Blend number | Conventional | Optimised |
|---|---|---|
| 1 | 96.3 | 95.3 |
| 2 | 96.2 | 95.3 |
| 3 | 96.5 | 95.4 |
| 4 | 96.3 | 95.4 |
| 5 | 96.4 | 95.3 |
| 6 | 96.4 | 95.3 |
| 7 | 96.4 | 95.4 |
| 8 | 96.2 | 95.3 |
| 9 | 96.3 | 95.4 |
| 10 | 96.3 | 95.4 |
| 11 | 96.3 | 95.3 |
| 12 | 96.5 | 95.4 |
| 13 | 96.3 | 95.4 |
| 14 | 96.1 | 95.3 |
| Grade spec | 95 |
EntroMetrix builds physics informed property models of the nonlinear blend behaviour, combining simulations and mechanistic blend models with the plant's own measurements and analyser records to capture how octane and the other quality properties respond to each component. A reinforcement learning agent then proposes component recipes online, moving the recipe in small mass balanced steps that hold every grade specification while lowering cost and shrinking giveaway. Because it learns the blend mechanism from data, a component switch or a shift in component quality no longer forces an octane overshoot or a spec breach, and the specifications are held as constraints by a safe reinforcement learning layer that keeps the policy inside grade, tank and component limits. The system is retrospective and offline first, scored against the plant's past blends before any live use.
| Blend cost (index) | Blends on spec first time (%) | |
|---|---|---|
| Conventional practice | 1.10 | 95.6 |
| Chosen recipe | 0.89 | 97.6 |
The models are built from data the plant already holds. Component and product analyser records, tank movements and the blend history are enough to learn how octane and the other properties respond to each component, and the grade specifications together with the tank and line limits are set with the blending team. Assumptions are documented and reviewed before any recipe is proposed.
The method has been demonstrated on nonlinear gasoline blending. A property model of the kind used here predicts octane from the component recipe to within a few tenths of a research octane number, and against that model the agent recomputes a full on spec recipe in seconds. Where a conventional linear recipe overshoots octane and breaches a component limit after a feed change, the learned policy holds every specification through the same change, which is where the giveaway and reblends come out.
| Baseline | Optimised | |
|---|---|---|
| Octane giveaway | 100 | 90.7 |
| Blend cost | 100 | 97.4 |
| On spec first time | 100 | 106.8 |
| Reblends | 100 | 91.6 |
Validation is retrospective and blind. Recipes are scored against the plant's own past blends before any live use, and the policy is constrained to stay inside grade, tank and component limits, so proposed moves remain within ranges the blender already accepts. The system runs offline, isolated from control systems, and proposes recipes for the blender to approve rather than acting on the plant, with the cost, giveaway and on spec position of each recipe shown.
| Blend number | Conventional | Optimised |
|---|---|---|
| 1 | 1.2 | 0.3 |
| 2 | 1.4 | 0.3 |
| 3 | 1.3 | 0.3 |
| 4 | 1.2 | 0.3 |
| 5 | 1.2 | 0.4 |
| 6 | 1.2 | 0.4 |
| 7 | 1.3 | 0.3 |
| 8 | 1.5 | 0.3 |
| 9 | 1.3 | 0.4 |
| 10 | 1.5 | 0.3 |
| 11 | 1.5 | 0.2 |
| 12 | 1.4 | 0.4 |
| Grade spec | 0 |
The optimised policy stays just on the safe side of the grade specification, taking out the margin that is otherwise given away.
At equal quality the optimised recipe draws less on the high value components and costs less per tonne.
Learning the blend mechanism lifts the on spec share and takes out reblends.
| High value components | Other components | |
|---|---|---|
| Conventional | 60 | 40 |
| Optimised | 57 | 40.4 |
| Baseline | Optimised | |
|---|---|---|
| On spec first time | 85 | 91 |
| Reblends | 15 | 7 |
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