Transient hydrogen and CO₂ pipeline modelling, in your browser

The numbers that pipeline engineers don't question.

FlowTran-X is built on SIROGAS — the calculation engine with over 50 years of validated use in gas and liquid pipeline simulation, now running on AWS with modern multi-user access, no local install, and results you can interrogate the moment a calculation completes.

50+
Years of validated pipeline physics
SIROGAS
The calculation engine behind FlowTran-X
AWS
Cloud compute — no network size limits
Capabilities

Purpose-built for serious pipeline problems.

Steady state & transient in one model

Model valve closures, compressor trips, pipe breaks, and linepack tracking with the same engine that handles routine design.

Multiple fluid compositions

Gas, liquid, dense phase, hydrogen blending, liquid CO₂. Composition variations per supply point, per timestep.

No network size limits

AWS removes the local-machine constraint. The only boundary is available cloud memory.

The engine

SIROGAS. The calculation standard for 50 years.

First written in 1974 for nuclear reactor cooling (the NAIAD program). Extended for natural gas transmission at CSIRO from 1982, with The Pipeline Authority, and renamed SIROGAS.

Analytic thermodynamic derivatives — not numerical approximation. University courses in Canada, the Netherlands, Italy, and the UK were built around it. Pipeline operators across Australia, South Korea, China, and Sri Lanka relied on it.

FlowTran-X puts this engine in a browser. No dongle. No local-machine constraint. No CSV export. No single engineer carrying all the knowledge.

Engine specification
  • BWRS EOS (Starling 1973), 15 component gases
  • BWRS-HCO for hydrogen blending
  • Linear Liquid EOS
  • NIST REFPROP EOS (15 natural-gas components)
  • Dense phase / supercritical CO₂
  • Direct solver (standard networks)
  • Analytic thermodynamic derivatives
  • Automatic timestep control
  • Restart from prior simulation state
Fluid support

Single-phase. Every relevant fluid.

Gas

Natural gas, methane, ethane, propane and 15 standard BWRS component gases. Wobbe Index, calorific value, Dutton interchangeability.

Liquid & Dense Phase

BWRS liquid and dense phase above critical pressure. LiqCO₂.eqs for carbon dioxide transport modelling.

Hydrogen

BwrsHCO.eqs adds hydrogen and carbon monoxide as perfect gases. Blending per supply point with full composition tracking.

Multi-fluid blending

Multiple fluid mixtures per model. Variable composition over time. Each supply point specifies its own blend.

FlowTran-X is purpose-built for single-phase simulation. If you need two-phase or multiphase modelling, we will tell you directly.

“The same trusted engine. Without the dongle, the Excel dependency, or the one engineer who knows how it works.”

FlowTran 2.0 required a local machine, a hardware dongle, and deep familiarity with a non-intuitive interface. FlowTran-X runs in a browser. Multiple engineers can work on the same model simultaneously. Results are visible immediately — no CSV export, no Excel pivot. Your existing models import directly. The engine is unchanged; everything around it has been rebuilt.

The engine hasn't changed. The access has.

FlowTran-X is backward compatible with all existing FlowTran 2.0 models. Your existing work imports directly.