Case study · HPHT reactors & cells
High-pressure rotating reactor for mechanochemistry
For a public research lab in materials chemistry, IRIAN Mecatronics designed and built a high-pressure rotating reactor for mechanochemistry studies in supercritical CO2. This custom equipment performs ball milling operations at up to 250 bar (3,625 psi) and 100°C (212°F), ensuring a perfect seal during continuous rotation.
At a glance
- Client
- Public research laboratory in materials chemistry
- Field
- Materials Chemistry
- Technique
- Mechanochemistry in supercritical CO2
01 — The research question
How to seal and stabilize a multi-liter reactor that rotates under high pressure and temperature?
Many synthesis and testing processes in chemistry, geoscience, and materials science require vigorous agitation to ensure mass transfer between phases or to provide mechanical energy. When these processes must be conducted under high pressure and/or high temperature, rotating the entire reactor is often the most effective solution, but it poses a major technical challenge in sealing the moving shaft. This project aimed to perform ball milling operations in supercritical CO2 at 250 bar (3,625 psi) and 100°C (212°F). Such an operation is impossible with standard equipment: commercial mills are not designed to hold pressure, and standard high-pressure reactors are typically static, with internal stirring that is unsuitable for ball milling.
The technical challenge was to maintain a perfect dynamic seal on a large-diameter rotating shaft subjected to 250 bar (3,625 psi) and 100°C (212°F), while withstanding the chemical environment of supercritical CO2 and the mechanical stresses of rotation.
02 — Our approach
Designing a high-pressure rotating reactor: key decisions
Ensuring a dynamic seal at 250 bar
Supercritical CO2 is an aggressive solvent for polymers, and the combination of pressure and rotational speed (400 rpm) creates extreme stress. We selected a multi-barrier sealing system with specific materials and hardened contact surfaces, ruling out single-seal solutions. The benefit is total safety and the ability to run long-duration experiments without leaks.
Instrumenting and heating the rotating vessel
Measuring internal pressure and temperature and powering a heating jacket without tangled cables is a classic challenge in rotating systems. The chosen solution is a slip ring, which provides a reliable and continuous electrical connection. This gives the operator real-time control and monitoring of key reaction parameters, which is essential for data quality and safety. A similar principle is used in our multi-mode reactors for geochemistry.
Securing operation at physical limits
the pressure × Velocity (PV) product has a physical limit beyond which the seal is no longer guaranteed. Rather than a simple alarm that relies on the operator, we implemented an active safety feature: the control system automatically reduces the speed if the pressure increases, to always stay below the safety threshold. The equipment is intrinsically safe across its entire operating range.
03 — Technical specifications
| Operating pressure | 250 bar (3,625 psi) |
|---|---|
| Internal volume | 2 L |
| Operating temperature | Ambient to 100°C (212°F) |
| Maximum rotational speed | 400 rpm |
| Total cell mass | 19 kg |
| Total mass (bench + cell) | 120 kg |
| Overall dimensions (W x D x H) | 1324 x 714 x 1935 mm |
| Cell positioning | Horizontal or vertical, with locking system |
04 — Other applications
Does your process require intense agitation under high pressure?
Pharmaceuticals / fine chemicals
This principle applies to slurry hydrogenation reactions under high-pressure hydrogen. The concept of a rotating reactor, dynamic sealing, and control system would remain, but the materials would need to be certified as H2-compatible, and the entire system would require ATEX certification.
Geosciences
To study fluid-rock interactions under reservoir conditions, a rotating reactor can simulate flow using centrifugal force. The principle of a sealed HPHT rotating vessel and a slip ring would be retained.
Waste Treatment
Wet air oxidation or hydrothermal liquefaction processes for biomass treat slurries under pressure and temperature. The robust rotating reactor concept is ideal for managing these multiple phases. The materials, volume, and loading systems would need to be adapted.
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