Compare · HYSYS alternative · process simulation
WorkSync FlowSync vs. Aspen HYSYS: which process simulator fits the work that fills your day?
Aspen HYSYS is the long-running gold standard for process simulation in oil and gas, especially on greenfield design and complex thermodynamics. The trade-off is fit: a $40K-per-seat HYSYS license is overkill for the daily revamp, debottleneck, and troubleshooting work that makes up most of operator engineering. WorkSync FlowSync Process Simulator is built for that 80%. HYSYS stays the right tool for the remaining 20%, and we feed it from the same Model Builder output FlowSync runs on.
WorkSync vs Aspen HYSYS: the honest comparison.
| Capability | Aspen HYSYS | WorkSync FlowSync Process Simulator |
|---|---|---|
| Greenfield design with deep thermodynamic libraries | Industry standard. Decades of refinement on hydrocarbon thermodynamics. | Not the target use case. HYSYS remains the right tool for full greenfield process design. |
| Day-to-day revamp / debottleneck / troubleshooting | Capable but heavyweight; engineers often spin up a full file for a 30-minute question | Built for it. Right-sized engine for daily questions. |
| Gas processing (sweetening, dehydration, compression, separation) | Full coverage | Full coverage for the daily-driver work; ships with right-sized engines for the same unit operations |
| Equipment sizing (separators, compressors, heat exchangers, dehy units, amine systems) | Yes | Yes |
| Time-to-answer for a typical sensitivity | Hours-to-day (build the file, run, interpret) | Minutes (model already built; sensitivity runs in-place) |
| Live operating data integration | Manual data load | Connected to the WorkSync Data Hub; sims see current SCADA conditions |
| AI engineer agent (cited answers, MOC drafting, sensitivity runs) | Not native | Yes — Taylor reads every drawing and cites every answer |
| Pricing model | Per-seat, typically $40K+ per engineer per year | Per-module annual license. Below VP signing authority. |
| Co-exist with each other? | , | Yes — many customers run HYSYS for greenfields, FlowSync for the daily work |
Because your evaluation deserves it.
Aspen HYSYS is the right call in some situations. WorkSync is the right call in others. Here’s the real-world split.
01When Aspen HYSYS wins
You are designing a greenfield process facility
Full greenfield design with deep thermodynamic packages, complex column rating, multi-phase equilibrium across non-standard chemistries — HYSYS earned its position. WorkSync does not aim to replace it for that work.
You need the deepest specialty packages (acid gas, refining, polymers)
Aspen's ecosystem of specialty thermodynamic packages and reactor models is broad. For non-standard chemistries or specialty refining work, HYSYS is the call.
Your team has years of HYSYS muscle memory
If your engineers think in HYSYS, the change-management cost of moving day-to-day work into a different simulator may not pencil out. Co-exist is the better path: HYSYS for the deep work, FlowSync for the daily questions and live-data simulations.
02When WorkSync wins
Most of your engineering work is the 80% that does not need HYSYS
Revamps. Debottlenecks. Troubleshooting a separator that started carrying-over after a new well came online. Setting an amine reboiler duty for the next month's gas composition. These are the questions that fill an engineer's day, and they do not need a full $40K HYSYS license per seat.
You want the answer in minutes, not hours
FlowSync's Process Simulator runs against the same Model Builder output that drives Flow Simulator. The model is already built. The sensitivity is a minute, not a day. If your engineering team has a queue of "quick" questions waiting for someone with a HYSYS seat, FlowSync clears the queue.
You want simulations on live operating data
HYSYS runs whatever you load. FlowSync runs against the Data Hub, so the inlet composition, the operating pressure, and the duty are current. Daily-driver process work is accurate without manual data refresh.
You want an AI engineer agent on tap
Taylor reads every drawing in your project folder, every MOC from the last decade, every API/ASME/AGA code your team references. She cites the source. Cuts the bottleneck of the senior engineer who is in a meeting without replacing the simulator your team already uses.
HYSYS for the 20%. FlowSync for the 80%. Same model.
The cleanest pattern: FlowSync handles the daily-driver work (revamps, debottlenecks, sensitivity studies, equipment sizing for everyday changes). HYSYS stays the system of record for greenfield design and the deep thermodynamic work specialty packages exist for. Both run on the same Model Builder output, so your asset spec is one source of truth, not two.
Net effect: same HYSYS seats for the engineers who need them, but the rest of the team gets a right-sized tool for the work they actually do every day. Engineering throughput goes up without anyone losing the depth they relied on.
“We had three HYSYS seats and a queue of process questions a mile long. Most of them did not need HYSYS at all. With FlowSync the queue cleared in a week. We still keep the HYSYS seats for the work that needs them.”
Process engineering leadership · Mid-tier producer · Multi-basin
Common questions
Will FlowSync replace Aspen HYSYS entirely?
For most teams, no. HYSYS is the right call for greenfield design and the deepest thermodynamic work. The recommendation is co-existence: HYSYS for the 20% that needs it, FlowSync for the 80% that does not. Both run on the same Model Builder output.
What unit operations does FlowSync Process Simulator cover?
Gas processing, dehydration, sweetening, compression, separation, and small-facility design. Equipment sizing for separators, compressors, heat exchangers, dehy units, and amine systems. Sized for the daily-driver work, not the once-a-decade greenfield.
Can FlowSync export to HYSYS?
The canonical asset model FlowSync builds is the same input HYSYS expects for the unit operations both cover. The handoff keeps your existing HYSYS workflow intact while removing the manual model-build step.
How does pricing compare to HYSYS?
HYSYS is per-engineer-seat, typically $40K+ per year per seat. FlowSync Process Simulator is per-module annual license, below VP signing authority. Operators commonly keep two or three HYSYS seats for the deep work and run FlowSync as the daily-driver simulator for the broader engineering team.
Does FlowSync handle non-standard chemistries (specialty solvents, acid gas blends)?
Standard hydrocarbon thermodynamics, gas processing, and amine systems are in. Specialty packages where Aspen has decades of refinement remain HYSYS territory, and we will tell you honestly when the work belongs there.
See WorkSync on your data, alongside your existing stack.
Request a free trial. Qualified operators get a 4-week proof of value at no license cost. Integration in under 1 week; full standup in 2.