Case study · Geoscience & subsurface studies

Studying six-month reaction kinetics in corrosive media: a custom six-reactor HPHT bench

For a major geoscience research center, IRIAN Mecatronics designed and built a test bench with six independent HPHT reactors. The system simulates long-term biogeochemical processes by maintaining stable, extreme conditions: 150 bar (2175 psi) pressure, 150°C (302°F) temperature, and a corrosive environment with brine and H₂S.

Client: A major geoscience research center
Field: Geochemistry
Technique: Kinetic study in a three-phase environment

01 — The research question

How to study reaction kinetics over several months without equipment contaminating the sample?

Studying very slow reaction kinetics, such as fluid-rock interactions in geological storage, requires keeping a sample under stable conditions for weeks or months. In a corrosive environment, the equipment itself becomes a source of contamination: even minor ion leaching or wall effects can skew the analyses and invalidate a time-consuming test.

The challenge for this project was to combine several requirements that are rarely met at once: extreme corrosion resistance (high-salinity brine + H₂S), stable HPHT conditions for six months, effective mixing for a three-phase system (solid, liquid, gas), and near-zero dead volume for valid sampling. No off-the-shelf custom HPHT reactor could meet all these requirements simultaneously across six parallel units.

Ensuring a sample remains uncontaminated and representative over a very long period in an extremely corrosive HPHT environment that degrades equipment and skews measurements.

02 — Our approach

The design approach: four choices to ensure measurement reliability

To meet the project's specifications, our engineering team focused on four key areas. Each decision was made to ensure the measured data reflects only the sample's chemistry, not the limitations of the instrumentation.

Ensuring absolute chemical inertness

Over six months, even high-grade stainless steel would have suffered from pitting corrosion in the presence of brine and H₂S, contaminating the test. We therefore manufactured all wetted parts from Hastelloy C276. Using a single alloy eliminates any risk of galvanic corrosion and ensures complete chemical inertness.
Ensuring representative sampling

For a kinetic study, any fluid stagnating in a sampling line (dead volume) skews the analysis. Instead of using remote sensors and valves, we integrated all measurement and sampling functions as close as possible to the reaction volume, directly on the reactor head, thereby eliminating dead volumes.
Homogenizing a three-phase system (solid-liquid-gas)

The reactions being studied depended on the interfaces between phases. It was crucial to keep the rock particles in suspension and maximize gas-liquid mass transfer. A powerful, custom-designed mechanical stirring system was developed to ensure the medium's homogeneity and to confirm that the measured kinetics were driven by chemistry, not by physical limitations.
Facilitating parallel operation of six reactors

Managing six long-term tests is demanding. To optimize experimental throughput and safety, we mounted all six reactors on a single frame. This design centralizes control and monitoring on a single interface while facilitating individual access, assembly, and cleaning for each unit.

03 — Beyond this project

Does your project have similar requirements?

Fine chemicals / catalysis

For studying long-duration reactions (e.g., hydrogenation, synthesis) with a solid catalyst where purity is critical, the principle of a stirred, inert HPHT reactor with low dead volume remains the same. The material (Inconel, Titanium) and certification (ATEX) would change depending on the reactants.

Energy / CO₂ Capture

For testing material aging or solvent efficiency in prolonged contact with supercritical CO₂, a common challenge in custom CCUS reactor systems, and acid gases (H₂S), the need for multiple parallel HPHT vessels, acid corrosion resistance, and stable long-term conditions are directly transferable requirements.

New materials / biomimicry

For synthesizing materials via hydrothermal routes (e.g., zeolites, ceramics), precursors must be kept in suspension at high pressure and temperature. The need for stirred reactors that can withstand extreme pH levels and provide precise thermal control to manage crystallization presents a very similar challenge.

04 — Specifications

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

Show specifications · 6, independently controlled · up to 150 bar (2175 psi) · up to 150°C (302°F)

Technical specifications — Studying six-month reaction kinetics in corrosive media: a custom six-reactor HPHT bench
Number of reactors	6, independently controlled
Operating pressure	up to 150 bar (2175 psi)
Operating temperature	up to 150°C (302°F)
Wetted material	Hastelloy C276
Typical test duration	up to 6 months
Liquid medium	Brines with salinity up to 360 g/L

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 reactor be used for studies with pressurized hydrogen?

Yes, the principle of a multi-reactor bench for long-term testing is transferable to hydrogen applications. The main adaptation would be the material selection to prevent hydrogen embrittlement. The entire project would also be designed to comply with ATEX regulations, which dictates specific choices for instrumentation, ventilation, and overall safety, as seen in our bench for flammable gases.

Is it possible to design a similar system for higher pressures, for example, 500 bar?

Yes, designing equipment for pressures up to several thousand bar is part of our core expertise. The design principles (chemical inertness, stirring, ergonomics) would remain valid. Moving to 500 bar would require a complete mechanical redesign (wall thickness, sealing technology, types of valves and fittings) in accordance with the Pressure Equipment Directive (PED) to ensure safety.

Is a single, larger-volume reactor an option instead of six small ones?

Absolutely. The choice between multiple small reactors and a single larger one depends on the objective. A multi-reactor setup is ideal for parallel parameter screening. A single, larger-volume reactor is relevant for scale-up studies or pilot batch production. The overall architecture, particularly the stirring and thermal management systems, would be adapted to ensure homogeneity on a larger scale.

Can this reactor bench operate in continuous mode instead of batch?

This system was designed for batch experiments, optimized for very long residence times. Switching to continuous flow operation (CSTR-type) is a different project that fundamentally changes the design. It requires adding continuous injection and withdrawal systems and a different approach to homogenization. We also design custom continuous flow reactors for this type of need.

Is your research limited by corrosion, contamination, or the stability of your current reactor?

Describe the reaction you want to study and the conditions that cause your standard equipment to fail. Our engineering team will analyze your project's feasibility and get back to you with a proposal for a custom solution.

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