Case study · Fluid dynamics & phase behavior

Visualizing gas hydrate formation: a modular high-pressure sapphire reactor

For a global energy leader, IRIAN Mecatronics designed and manufactured a custom high-pressure reactor to visualize gas hydrate formation. The equipment is used to study the phenomenon at 120 bar (1740 psi) in a corrosive environment, featuring two interchangeable experimental configurations: a static porous medium and a stirred medium.

Client: A global energy leader
Field: Oil & Gas, geosciences
Technique: Phase change visualization, crystallization kinetics

01 — The research question

How to visualize and quantify crystallization under pressure with varying flow conditions?

Studying the formation and dissolution of crystals (hydrates, salts, polymers) under pressure is crucial for process control in chemistry, geosciences, and energy. The phenomenon is highly dependent on local conditions such as temperature, pressure, and flow. Observing the process across a representative volume, rather than through a small viewport, is essential for understanding its kinetics and validating simulation models. This is a key challenge in Fluid Dynamics & phase behavior.

Our client needed to understand CO2 hydrate formation in two scenarios: one simulating a reservoir (static porous medium) and the other a pipeline (agitated medium). Standard reactors do not offer full-column visualization, and existing sapphire cells were too small to accommodate the required complex, interchangeable instrumentation. An off-the-shelf solution combining full visibility, high pressure, corrosion resistance, and this level of modularity did not exist.

To enable direct visual observation over the full height of a 120 bar (1740 psi) column, accommodate two radically different and interchangeable internal experimental setups, and withstand a corrosive environment.

02 — Our approach

A modular design for a dual experimental challenge

To meet this need, our engineering team designed the equipment based on four principles: total and undistorted visibility, maximum experimental modularity, material compatibility with corrosive fluids, and safe handling.

Ensuring full visualization at 120 bar

To observe the location and kinetics of crystallization over a 200 mm height, a metal cell with viewports would have offered a discontinuous view. We therefore built the reactor around a monolithic sapphire tube, which serves as the cell body. This approach ensures a complete and continuous view without optical distortion.
Enabling two test scenarios in a single rig

Rather than building two separate test rigs, we designed a modular system. The cell body is constant, but two different top assemblies ('heads') are easily interchangeable. Each head integrates specific instrumentation and actuators: one for an instrumented sand pack, the other for a stirrer with torque measurement. This design maximizes the value of the investment.
Ensuring chemical compatibility and thermal control

To withstand the corrosivity of saltwater and CO2, all wetted parts were machined from Titanium Ta6V and Hastelloy. To regulate the temperature from -10°C to +80°C (14°F to 176°F) without obstructing the view, an external double jacket was integrated, ensuring homogeneous and reliable thermal control.
Facilitating handling and maintenance

Changing configurations and cleaning the system require frequent disassembly. To make these operations simple and safe, the entire column assembly is mounted on a pivoting, lockable stand. This allows the operator to tilt the equipment effortlessly for draining, filling, or maintenance.

03 — Beyond this project

Does your project have similar requirements?

Fine chemicals / pharmaceuticals

A common challenge is visualizing crystallization or polymerization kinetics to optimize a process. The core design—a jacketed sapphire column, modularity, and torque measurement for viscosity tracking—can be adapted for these applications. See our page on custom HPHT reactors & cells.

Geosciences / geological CO2 storage

This involves studying fluid-rock interactions under reservoir conditions. The HP cell with full visualization and the instrumented sand pack setup would be retained, with materials and pressure ranges adapted to accommodate rock core samples.

Food & beverage / supercritical extraction

To observe the effect of supercritical CO2 extraction on a solid matrix, the visualization cell and precise P/T control would be key features. Materials would be adapted to meet sanitary standards (e.g., 316L stainless steel, PEEK), and the design would be optimized for easy cleaning.

04 — Specifications

The values for this project. Every system is custom-built, so they adapt to your requirements.

Show specifications · 120 bar (1740 psi) · -10°C to 80°C (14°F to 176°F) · 63 cm³

Technical specifications — Visualizing gas hydrate formation: a modular high-pressure sapphire reactor
Operating Pressure	120 bar (1740 psi)
Operating Temperature	-10°C to 80°C (14°F to 176°F)
Usable column volume	63 cm³
Sapphire tube dimensions	Ø 20 mm x 200 mm
Maximum stirring speed	1500 rpm
Wetted Materials	Titanium Ta6V, Hastelloy X (probes)
Instrumentation (sand pack setup)	Up to 4 thermocouples
Instrumentation (stirred setup)	Real-time torque measurement, integrated thermocouple

IRIAN Mecatronics designs and builds custom high-pressure, high-temperature equipment for research laboratories, technical centres and industry.

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05 — FAQ

Frequently asked questions

Can this type of sapphire reactor be used with more corrosive fluids like hydrogen sulfide (H2S)?

Yes, the sapphire cell design can be adapted. The main modification would involve selecting different wetted metallic materials, such as switching from titanium to superalloys like Hastelloy C276 or Inconel 718, which are known for their resistance to H2S. Sealing solutions and certifications (e.g., ATEX for explosive atmospheres) would also be specifically reviewed for the application.

Is it possible to adapt this modular reactor for much higher pressures, such as 500 bar?

Reaching 500 bar (7250 psi) with a monolithic sapphire tube of this size becomes technically complex and costly. For such pressures, the design approach would change: we would likely opt for a titanium or superalloy metal cell fitted with one or more smaller-diameter sapphire windows to preserve visualization.

Can your modular design accommodate other types of internals, like a circulation loop or sampling ports?

Absolutely. Modularity is at the core of this design. The interchangeable 'head' system is specifically engineered to integrate a wide variety of functions. For example, a custom head could include ports for an external recirculation loop, sampling capillaries at different heights, or optical probes (e.g., Raman, spectroscopy).

How is the reliability of temperature and torque measurements ensured in a system with interchangeable parts?

Reliability is ensured through rigorous design and qualification procedures. Each interchangeable head is a complete, instrumented assembly, tested and calibrated in our workshop during the Factory Acceptance Test (FAT). Connectors are robust and precisely positioned to guarantee measurement repeatability. Direct visualization also allows operators to correlate sensor data (like a torque spike) with an observed physical event (like solidification).

Need to visualize a high-pressure phenomenon not covered by standard equipment?

Describe your challenge, no matter how specific. Our in-house engineering team will analyze your project's feasibility and get back to you with a detailed technical proposal.

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